From the ABC 7 Weather team

Frost Season: When Will Washington Have Its First One?

October 19, 2014 - 06:31 PM
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A Frost Advisory is posted when temperatures are expected to be 33 to 36 degrees on clear, calm nights during the growing season. An even colder night that brings temperatures to or below freezing requires the weather service to issue a Freeze Warning.

Both of these cold weather alerts are only posted until the end of the growing season. When defines the conclusion to the growing season? A widespread freeze (temperatures at or below freezing) that kills off outside vegetation left uncovered.

The Allegheny mountains far west of Washington are first to see the end of the growing season. As time goes on during the fall, the temperatures eventually get cold enough to end the growing season from the Allegheny Foothills to the Blue Ridge.

First Frost

The Washington area has its first frost usually around this time; mid-October. In an average fall then, by November 1, temperatures likely have dipped below freezing to end the entire Mid-Atlantic’s growing season.

Frost Advisories and Freeze Warnings cease to be posted then during the winter but are warranted when a late-spring freeze is expected to cause damage to plants and crops.

Below is a table that lists the typical first fall frost and last spring frost dates. If temperatures are expected to be near or below freezing after the typical last spring frost dates, Frost Advisories and/or Freeze Warnings will be posted.

First Frost

Stay with ABC7 and WTOP for the latest forecasts and cold weather alerts as Autumn continues.

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Weak El Nino? What could that mean for D.C. Winter - Comparing the past

October 17, 2014 - 03:15 PM
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Now that we have established that in the D.C. region, the summer of 2014 wasn’t quite as cool as we had perceived it to be, we can now move on to the winter of 2014-2015. Does a cool summer mean a harsh winter? I have been getting this question a lot, especially as we head into the end of October.

I decided to go back to ALL of the harsh winter’s Washington D.C. has recorded since 1899 and tried to find exactly what the summer preceding that harsh winter was exactly like and if we were experiencing a La Nina year, an El Nino year or a neutral year since that gives us an idea of our winter long range forecast. Again, these are all from Washington, D.C. National Weather Service forecast office (it had moved a couple times throughout this history but was always within the District of Columbia). 

1899: The Great Eastern Blizzard of ’99.
The Winter: This storm moved into the Washington D.C. region on Valentine’s Day, a Tuesday in 1899. Snow was reported as far south as Florida with around 21.0” of snow falling on the Washington D.C. and Baltimore area and up to 16.0” as far as New York. Pretty gusty winds that accompanied the Blizzard caused serious snow drifts that blocked transportation lines into Washington D.C causing a coal shortage. The Washington area had a snow depth of 34.0”. This was also the winter of The Great Arctic Outbreak in winch temperatures were so cold all across a good portion of the United States that the National Weather Service reports that ice flowed from the Mississippi River into the Gulf of Mexico.

The Summer of 1898:  With an average summer temperature of 75.0 degrees and an observed temperature of 76.0 degrees, the meteorological summer of 1898 (June – August) was 1.0 degrees WARMER than average.

January 28, 1922 “Knickerbocker Storm”:

The Winter: This storm was a crushing blow to the Washington D.C. area. A heavy snow of 28.0” was measured in Washington D.C. with higher amounts around the regions. This was the infamous “Knickerbocker Storm” where around 100 people were crushed to death as the roof at the Knickerbocker Theater on 18th and Columbia in NW Washington succumbed to heavy snow.

Summer of 1921: The summer preceding the “Knickerbocker Storm” was 0.83 degrees WARMER than average, but just by a very thin margin. The average temperature was 74.6 degrees for the summer and the summer of 1921.

April 1st, 1924 “Aprils Fools Day Storm”:

While this storm was mild in comparison with other storms of the past, this was the latest snowfall of the season of this amount. (This was considered a major snow storm because it accumulated more than 4.00”). Actually 5.00” of snow fell on the Washington area (a trace of snow fell on May 10th, 1906 but again, this was the most snow recorded this late in the season). Baltimore received 9.00” of snow with this storm.

The summer of 1923 was once again just a touch on the warmer side with the average temperature for the summer at 74.6 degrees and an observed temperature for the three summer months was 75.2 degrees. This means that D.C. was 0.63 degrees WARMER the summer before the April’s Fools Day Storm.

February 7th, 1936:

While this storm does not have a name, the Spring following this Winter helped set up for “The Great Spring Flood of March 1936” which was recorded as one of the worst floods for the Potomac River and Washington D.C. More than 14.0” of snow fall around Washington D.C. with more amounts through the Eastern Shore, Southern Maryland and south. All that snow helped lend to the massive flooding of the Potomac River through the spring.

Temperatures for the summer of 1935 were at 74.6 degrees for an average. The summer was very warm with temperatures topping out at 1.95 degrees ABOVE the normal temperature!

March 29th-30th 1942

This was a big storm that is actually still spoken about to this day! The “Palm Sunday Snowstorm” was a late bloomer, moving in at the end of March. However, it was a big snow producer dropping a foot of snow on Washington D.C. That was a minimal total compared to Baltimore, which received the greatest snow accumulated with one storm in 20 years! Baltimore recorded 22.0” of snow and Hagerstown measured 22.0” of snow as well in about 24 hours!

Chalk it up as another warm summer around Washington D.C. with temperatures 1.0 degrees WARMER than average. The average temperature for the summer of 1941 was 74.6 degrees with the observed temperature at 75.6 degrees.

January 30th-31st 1966

Strong El Nino Year. A pretty bad winter was upon the D.C. region during 1965-1966. With already snow on the ground, a blizzard came whisking through the region dropping one to two feet of snow through Virginia and Maryland. Washington D.C. recorded 14.0” of snow while Baltimore received just around a foot. There of course were some higher totals through Fredericksburg and Manassas.

The summer leading up to the fairly bad winter was almost near normal. The average temperature for the summer of 1965 was 76.3 with a recorded temperature of 76.0 degrees. That means the summer of 1965 was 0.3 degrees BELOW average, slightly just still below.

January of 1977 “The Bicentennial Winter”

Weak El Nino Year: This was a harsh one to say the least. This was one of the coldest winters recorded on the East Coast. The average temperature in Washington for January was 25.4 degrees which was the coldest since 1856 when the average temperature was 21.4 degrees (the normal temperature for January was 34.6 degrees)! The Carter Administration was getting settled into Washington and starting on January 4th, snow kept falling every few days. It was just a few inches here and a few inches there. Believe it or not, the Tidal Potomac (which is salt water) was frozen solid with the cold temperatures! People could actually skate across it to the Memorial Bridge! This winter was terrible for everybody – in fact, snow was even seen in Miami, Florida on January 19th. (Courtesy of NWS-Sterling)

Looking back at the summer of 1976, the average temperature was just slightly above normal for the meteorological summer, only 0.8 degrees warmer. The average temperature for those months was 76.8 degrees and the D.C. area measured a summer with an average temperatures of 77.6 degrees.

February 18th-19th 1979


Neutral Year: “The President’s Day Storm” was a one that a lot of people around the region remember as well considering it was thought to be the worst storm to hit the Washington, D.C. region in 57 years. Snow was recorded as falling 2”-3” per hour during the storm! One of the most interesting facts about this storm is that there was a protest on the National Mall with tractor trailers and other large farm machinery to protest for higher agricultural pricing. The protestors on the mall ended up using their equipment to help people dig out of the depths of snow that were around 2 feet!


With another bad winter upon the D.C. area in 1979, the summer of 1978 was a hot one. Temperatures were 2.1 degrees ABOVE normal! The average summer temperature for that summer was 78.7 degrees and the Washington D.C. area observed a warm average temperature of 78.9 degrees.

February 11th-12th 1983


Strong El Nino Year: Up to this point in history, the February storm of 1983 was the 2nd greatest snowfall on record for the Washington D.C. region as 24-hour snowfall records were set in some of the surrounding areas and D.C. received 17.0” of snow with this storm. There was more snow if you traveled outside the city, snowfall totals were up to 2 feet in some areas. Not only was the region dealing with large snowfall totals but gusty winds also caused large snow drifts around the Mid Atlantic.


The summer preceding the snowstorm that beat out the President’s Day Snowstorm was actually slightly cooler than average. The average temperature for the summer of 1982 was 76.8 degrees and D.C. observed a temperature of 76.2 degrees. That means D.C was 0.6 degrees BELOW normal for that summer.

November 11th, 1987 “The Veteran’s Day Storm”


Moderate transitioning into Strong El Nino Year:
Who can remember this storm? I actually do because my mom had to learn how to drive stick in a snowstorm to get me to an emergency dentist for a screaming 5 year old-oh memories. The snow came down fast a furious and right and took people by surprise considering these were the days before Doppler radar. By the time the snow moved through Fredericksburg, dropping heavy amounts, it was too late and meteorologists didn’t even really grasp what was happening until snow reached the forecast office in Camp Springs. Around a foot of snow fell across the region as motorists were still out and about. Stranded cars decorated area roadways.


This was actually a very warm summer in 1987 and an early massive snowstorm that followed. Temperatures in the summertime were 2.2 degrees ABOVE normal. The average temperature for that summer was 77.0 degrees and D.C. topped out at 79.2 degrees!

March 13th – 14th 1993 “The Superstorm of March ‘93”

Coming out of Moderate El Nino this was a Neutral Year: Yet another memory because I was pretty sure, growing up in Winchester, VA, I was never going back to school after this one (which was fine by me at that point in my life). This was a massive storm, with the lowest pressure ever recorded at the storm’s center, that affected the entire east coast. Not only did it cause huge storm surge through the Florida panhandle and several tornadoes (several deaths resulted in those weather events as well), it dropped more than a foot of snow across multiple states. Although this was an incredible storm, D.C. has seen worse. D.C. recorded 13.0” of snow with almost a foot right outside the city; in the suburbs and in extreme southwest VA some totals were around 40.0”. There were plenty of strong winds accompanying the storm as well as this was a true blizzard. Snow drifts were over 12 feet, the National Guard was called in and there were several deaths not only from hypothermia and collapsed roofs but more commonly from overexertion leading to heart attacks while shoveling snow.

I wouldn’t exactly call the summer of 1992 a warm summer as temperatures in the Washington D.C. area were 1.9 degrees BELOW average. The average temperature for that summer was 77.0 degrees and D.C. measured a temperature of only 75.1. June and August were particularly cooler.

The Winter of 1994

Neutral Year: Several ice storms pelleted the D.C. area early in 1994 and temperatures plummeted below zero several mornings. This is thought to be the iciest winter on record for the D.C. area. During January and February, there were multiple storms that not only dropped sleet but snow a freezing rain as well. One storm in particular on February 10th left a coating of ice that was 1.00” to 3.00” thick across the region! Due to the thick coating of ice, there were several power outages as falling trees and power lines due to heavy ice were to blame. There was a disaster declaration given in our area and several injuries as a direct result of the heavy ice coatings.

The summer of 1993 was a warm one with temperatures 1.3 degrees ABOVE average. The average temperature was 78.0 degrees with the D.C. area observed a warm temperature of 79.3 degrees.

January 7-13, 1996: The Blizzard of '96

Weak La Nina Year: Another one for the record books, another one in recent memory. If you were north and west of the District, you were dealing with almost 40.0” of snow in some areas while D.C. was climbing out of around 20.0” of snow. Just as the roads started to clear, an infamous “Alberta Clipper” came diving into our area out of the northwest bringing another shot of several inches of fresh snowfall. And then, just when we thought it was over, a third storm moved into the area piling on another 4.0” to 6.0” of snow in the District with more north and west of D.C. All in all, around 2 to 3 feet of snow accumulated after these series of storms.

Another warm summer preceded a nasty and snowy winter with temperatures in the summer of 1995 1.1 degrees above normal. The average temperature was 78.03 degrees and we measure a temperature of 79.13 degrees bringing us a summer that was 1.1 degrees ABOVE average.


February 15-17, 2003
Moderate El Nino Year: Moving into the 21st century, another strong storm was moving up the eastern seaboard in mid-February while temperatures were measuring in the teens. As this Nor’easter was developing, heavy snow began to fall into the overnight and early morning hours on February 16th. The snow continued through Presidents Day morning, February 17th with totals in D.C. topping out at 26.8” of accumulation.

Another very warm summer on tap for the region as temperatures were 2.3 degrees ABOVE normal for the meteorological summer! The average temperature for that summer was 77.03 degrees in D.C. while temperatures warmed up to 79.36 degrees!

Winter of 2009-2010
Moderate El Nino Year: Here we go. The winter that never quit and the first time I had to get on air and say “yeah, we are going to see 30.0” - 35.0” of snow in spots (with only 2 years under my belt as a Chief Meteorologist at my first station, I was almost in tears to know that I could completely bust this forecast and never work again if this prediction didn’t come to fruition, fortunate for me, it did – unfortunately for everybody else, it did as well). This was one of many weekend storms we saw that winter with snow rates at 2.00” per hour at times. That was the first storm that came through on December 18th and 19th. By January, we had our fair show of “little” storms –dropping over 5.00” in spots at times and then came a blizzard on February 5th and 6th. That storm dropped 17.8” in D.C. with over 3 feet of snow north and west of town. Then just when we thought we had enough, we got another blizzard on February 9th and 10th. DC received an additional 10.8” of snow with up to 2 more feet recorded in areas. That winter, DC saw 56.1” of snow fall. That is the number one winter for snowfall in the Washington D.C. area as long as records have been kept (since the late 1800s)!

The summer of 2009 was pretty much on average. Yes, temperatures were just slightly cooler but only by 0.2 degrees. The average temperature for the summer of 2009 was 77.0 and we reached 76.8 degrees with a pretty warm August on tap to help close the deficit from a cooler than average June and July. Therefore, we were 0.2 degrees BELOW average for the summer of 2009.

Winter of 2013/2014

Neutral Year: And yes, another winter that never ended! I couldn’t believe that we were seeing St. Patrick’s Day snow. It was the middle of March and we had been dealing with minor snowstorms since December! We had a least 9 snow events last winter around the region where several inches of snow were reported. Eventually, DCA totaled 32.0” of snow for the season. 32.0” of snow does not even fall into the top 5 snowiest winters for D.C.

The summer last year was just slightly warmer than our average summer. The average summer temperature for June to August is 77.7 degrees and DC warmed up to 78.3 degrees for all three months combined. That is 0.6 degrees ABOVE average.

El Nino vs La Nina vs Neutral

 

 

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Wow. There is so much I can write on this subject. However, without turning into a very lengthy term paper with lots of graphics and images; let me just give you the short and skinny of it because these events strongly and often dictate the patterns of precip and temperatures globally. It is a very interesting meteorological phenomenon: the correlation between the sea surface temperatures and the atmosphere in the eastern Pacific. According to NASA’s definition of these events, “the development of El Niño events is linked to the trade winds. El Niño occurs when the trade winds are weaker than normal, and La Niña occurs when they are stronger than normal.”

El Niño: Unusually warm temperatures in the eastern Pacific when warm water builds up and migrates along the equator in the eastern Pacific. Of course, this warms the atmosphere creating thunder and rain storms.

 

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La Nina: Unusually cool temperatures in the eastern Pacific when cool water builds and migrates along the equator. This event cools the atmosphere and less water evaporates creating fewer rainstorms in response to the cooler and drier dense air.

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Neutral: This is the period (like we were in 2013-2014) when neither La Nina nor El Nino is present. This can be chalked up as a likely transition period to either a La Nina or El Nino event. Pretty much everything (ocean temps, tropical rainfall patterns and atmospheric winds) is right around average.

With that being said and according to the NWS, during El Nino years (and depending on the strength) “there appears to be some historical correlation between the strength of the El Nino and the warming in the Pacific Ocean and seasonable temperatures, precip and snowfall. Weak El Niño winters averaged below normal temperatures and precipitation, while strong El Niño episodes averaged above normal temperatures and precipitation. On average, the stronger the El Niño episode, the warmer and wetter the winters have been. These findings can partly be linked to a stronger than normal sub-tropical jet that typically occurs during moderate to strong El Niño winters, which would favor more active storm systems from the south that draw warm, moist air northward as opposed to the drier Alberta clippers from the northwest. Seasonal snowfall averaged above normal for weak, moderate and strong El Niño.” –credit www.erh.noaa.gov

 

 

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As for La Nina years (in the winter’s that I analyzed, I only recorded one – which was a weak La Nina from 1995-1996 and approximately 20 winters were influenced by La Nina episodes since 1950) and according to the NWS “there appears to be some historical correlation between the strength of the La Niña episode and seasonal temperatures locally at Washington D.C. and Baltimore: the stronger the La Niña, the warmer the temperatures averaged. Winter precipitation averaged slightly drier than normal during all La Niña intensities. Seasonal snowfall during La Niña winters averaged below normal during moderate and strong episodes. However, while almost all of the La Niña episodes are linked to near or below normal snowfall at Washington D.C. and Baltimore, the weak La Niña episode during the 1995-96 winter was an outlier in the dataset with well above normal snowfall for the season. In this case, the above normal snowfall was weighted heavily by the 6–8 January 1996 blizzard, when 17.1 (22.5) inches of snow fell at Washington D.C. (Baltimore). –credit www.erh.noaa.gov

 

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So what do we have in store for the end of 2013 through the spring of 2014 in terms of El Nino/La Nina?

The Climate Prediction Center has issued a statement that they expect (67% chance) of a WEAK El Nino to develop from October 2014 through December 2014 and continue through early 2015. Right now, observations in the Pacific are consistent with neutral conditions (same as last year) but there is a 67% chance of transitioning to most likely a weak El Nino event or a slight chance of a low-end moderate El Nino. Check our Alex Liggitt's blog for an in-depth look on the CPC's predition.

So there is the information and honestly we are just touching the surface as to what goes into a seasonal forecast: historic trends in both the winter and the summer, the Pacific Ocean temperature, wind movement, contrast and comparison. So if we happen to see a weak El Nino develop, maybe check back and see how that compares to the winter of 1977. Hopefully it WON’T be like that year.

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NOAA issues Winter Weather Outlook

October 16, 2014 - 03:44 PM
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NOAA issued its winter weather outlook today which features a temperature and precipitation outlook for the entire United States. The Mid Atlantic has typically been an extremely difficult place for seasonal forecasting, and last year was no different.

The outlook showed equal chances of above, below or near average conditions for both precipitation and temperatures for the 2013-14 winter. We all know that it was actually colder and wetter than average, with 32 inches of snow recorded at Reagan National Airport.

This winter, NOAA is predicting equal chances of near, above or below average temperatures.

NOAA Winter Temperature Outlook

They are also predicting a 30% chance of above average precipitation for the D.C. area and points east. The outlook did specifically state, "Last year’s winter was exceptionally cold and snowy across most of the United States, east of the Rockies. A repeat of this extreme pattern is unlikely this year, although the Outlook does favor below-average temperatures in the south-central and southeastern states."

NOAA Winter Precipitation Outlook

There is still a chance that El Nino will develop this winter, and the Climate Prediction Center has a 67% chance that it will develop by the end of the year. Strong El Nino patterns can affect the weather on a global scale.

Read much more about NOAA's Winter Outlook here.

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Heavy rain, isolated severe storms in D.C. Wednesday

October 15, 2014 - 11:45 AM
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LIVE DOPPLER RADAR  |  HD CAMS  |  SEVERE WATCHES & WARNINGS

The highest recorded wind gust today was 57 mph at Belle Haven CC in Alexandria. A few locations received 2 inches of rain and many locations recorded over an inch, which is great given the fact the region has been below average over the past month and a half.

The latest radar imagery continues to show the strongest shower and thunderstorm activity east of D.C. over St. Mary's, Calvert and Anne Arundel Counties in MD. The Flood Watch continues east of D.C. until 8pm.

Flood Watch until 8pm

1:54pm:

1:35pm:

1:32pm: Heavy showers and storms along with the potential for severe weather will continue to exist through the afternoon hours along and east of I-95 especially for Southern Maryland.

12:47pm: The tornado warned storm has exited the D.C. metro area and the strongest line of storms will continue to push north and east into areas such as Howard and Prince Georges Counties as well as Southern Maryland.

Moderate rainfall will continue through the afternoon hours.

12:20pm: A strong storm is approaching the D.C. Metro from the south moving north-northeast around 45 mph. This will come up on the region very fast so be sure to take shelter if you are in the city! Dangerous lightning, gusty winds and heavy rain are possible in this storm.

Heavy rain, gusty winds and an isolated severe storm cannot be ruled out heading into the afternoon hours. Temperatures ahead of the cold front are near 80 degrees in the D.C. Metro area while they are back in the low 60s west of D.C.

Flood Watch until 8pm

A Flood Watch remains in effect through 8pm this evening for the majority of the D.C. area for the potential of multiple inches of rain. Remember, if you encounter high water, turn around, don't drown. Some areas will see very heavy rainfall in a short amount of time. Various locations across the D.C. area have already received over an inch of rain.

48-Hour Rainfall Totals

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Heavy rain and storms headed to the D.C. region on Wednesday

October 14, 2014 - 02:38 PM
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It seems we are throwing it back to summer today (Tuesday) with temperatures around the 80 degree mark and humidity seeping through mostly cloudy skies. Another factor that makes this feel more like a summertime forecast is the threat of some severe weather for your Wednesday.

A powerful storm continues to crawl across the southern tier of the United States lifting to the north through Tuesday. An area of low pressure is lifting towards the Ohio Valley while its attendant cold front continues to move slowly to the east-northeast. The cold front will eventually cross through the area Wednesday, making it into the Atlantic and east of the Chesapeake Bay by the early overnight hours on Thursday morning.

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This storm has a history of being severe unfortunately and while I do not foresee a completely widespread severe outbreak across the WJLA viewing area, I do believe that along with damaging winds in some cells, flooding will be the main concern across the region. 
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Ahead of the cold front, showers will begin in the afternoon and evening hours on Tuesday. Mainly the area of concern will be well south and west of the listening area but a few showers could sneak slightly to the north, along and west of the Blue Ridge Mountains and into the northern Shenandoah Valley.

This is also the area that the Storm Prediction Center outlined for a 5% chance of severe thunderstorm winds or wind gusts (58 mph or over) within 25 miles of a point on the map within the shaded area:

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However, the National Weather Service in Sterling has issued a wind advisory (areas shaded in brown) from 6p.m. on Tuesday evening until 6a.m. on Wednesday morning. With this advisory, winds could move out of the south from 20 to 30 mph with gusts up to 45 mph. This obviously will make driving slightly more difficult, especially with high profile vehicles. There is also a chance for some downed trees with the higher gusts.
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So we will keep the chance of occasional showers to the west of the D.C. metro area through the evening and overnight hours. There could even be a few isolated storms within the WJLA viewing area during the overnight hours.

Through Wednesday morning, the frontal system will continue to slide to the east bringing the rain with it. Showers and some isolated storms will increase in coverage through the early morning hours and the rain and storms will continue to spread to the east through the early afternoon.

Unfortunately, this looks like it could be a messy commute for both the morning (if you are traveling from the west) as well as the evening commute (for everybody). Some of the storms in the afternoon hours could bring some damaging winds. However, the main threat will be the rainfall that we receive.

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From Tuesday to early Thursday morning, the region could receive anywhere from 0.75” -1.50” of rainfall accumulation east of the Blue Ridge Mountains and up to possibly 3.00” of rainfall accumulation west of the Blue Ridge Mountains in the Shenandoah Valley.

Since this system is just crawling, rain will just continue to pound the region. We are expecting the rain to be heavy at times since this system is feeding of moisture from the Gulf of Mexico and the Atlantic. We will continue to monitor the issuance of a Flood Watch for the area from the National Weather Service in Sterling.

Good news is that we could use the rain now. For Washington D.C., we are about 0.53” below for the month of October and 3.14” below for rainfall since September 1st 2014. The U.S. Drought monitor has place some of the areas in Virginia and Maryland in the “abnormally dry” sector which means that there is a chance that the region outlined in yellow is headed into drought conditions: short-term dryness means slowing planting and slow growth of crops or pastures.

 

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By Thursday, the heavy rain will be off the coast as the frontal system will be east of the region. However, we are still looking at some spotty rain showers for Thursday with cloud cover as that area of low pressure will be moving through the Great Lakes region (again – its attached cold front will be east of D.C. – see first graphic in this article for surface features on 8 a.m. Thursday). Temperatures will drop back to just slightly above normal for this time of year, in the low 70s. Sunshine returns for Friday!

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Total Lunar Eclipse Wednesday Early Morning

October 6, 2014 - 03:30 PM
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Photo: NASA/JPL Kieth Burns

   Set your alarm clock and wake up the kids a little early on Wednesday. Sky gazers will be treated to a beautiful celestial display just before sunrise. The full Hunter’s Moon will be out in all of its glory and the earth will cast a shadow over it. The total lunar eclipse will be visible for all parts of the United States, including right here in Washington, D.C.

Eclipse Viewing- NASA


 If you want to catch the show, you can watch it directly. No special viewing goggles needed. Totality begins at 6:25a EDT and the full eclipse will be at 6:55a. By 7:24a it’s all over, but the sun will be up by then, so it’s best to catch the first half of it here. Just look in the Western sky.

Photo- NASA


As the moon passes deep inside the shadow of the earth, a coppery glow appears. It's also known as the Blood Moon. According to NASA, sometimes you can see a turquoise color at the start of the eclipse. That’s ozone. The moon will appear larger in the sky than normal so it should make for some great photos.  Wednesday is two days past perigee, the point when the moon is closest to the earth giving it that larger appearance. Check out this neat animation of what it may look like from solarsystemscope.com

We’re keeping a close eye on cloud cover Tuesday night and Wednesday morning. Right now it looks like the showers and clouds will clear out just in time. Both the GFS and Euro clear us out ; but the NAM keeps some patchy clouds around. My confidence is high enough that I’d set my alarm early to catch a glimpse.

NAM Total Cloud Cover Wednesday Morning


This is the second of four total lunar eclipses in succession. Each separated by 6 lunar months. The series of total lunar eclipses is called a tetrad. The next one will be April 4th, 2015.

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Coldest Air in Months!

October 4, 2014 - 05:11 PM
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Hopefully you know where the sweatshirts and jackets are because you'll want them tonight and tomorrow!   After a gusty Saturday, winds will diminish overnight and, with clear skies, lows will tumble!   Check out these forecast lows for tonight.

The majority of the viewing area will remain above freezing; however, far western MD and the eastern panhandle of WV may see subfreezing temperatures.  Freeze warnings are in effect for these locations. 

We're not the only ones dealing with the big chill.  Look how many counties are under frost and freeze warnings and advisories across the Midwest.

The forecast low for Reagan National is 45°.  The last time the temperature fell below 50° at Reagan was on May 19th! 

After a cold start tomorrow morning, highs will only reach the upper 50s to low 60s!  Keep in mind, our average high this time of year is 72°.  The last time D.C. had a high of 62° was back on May 29th. 

Even though it will be quite chilly, we are not expecting to break any record low temperatures in the city.  The record low at Reagan is 37° set back in 1948.  The record low at Dulles is 32° from 1970 and 35° is the record low at BWI. 

Regardless, you'll want to bundle up tomorrow morning and you'll likely want the sweater or jacket throughout the day!  Here's to fall and the first weekend of October!

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2014 hurricane season winding down with only five named storms

October 4, 2014 - 06:00 AM
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With less than two months to go, the 2014 Atlantic hurricane season has been lackluster at best. Earlier this year, NOAA predicted near-normal to below-normal tropical season. One factor could be the development of El Niño along with cooler Atlantic water temperatures. The original forecast was for eight to 13 named storms, three to six becoming hurricanes and one or two becoming major hurricanes.

2014 Named Storms

NOAA was not the only organization to forecast less tropical activity this year. The Tropical Meteorology Project headed by Dr. William Gray and Dr. Philip Klotzbach predicted a season with only nine named storms, three becoming hurricanes and only one major hurricane.

2014 Named Storm Tracks (NOAA)

The official count this season: four hurricanes, one tropical storm and one tropical depression.  Don't let the slow season, so far, mislead you.  Hurricane season goes through November 30th.  Stay with the Stormwatch weather team for the latest tropical updates.

 

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Fun Fact Friday: Weather and Baseball

October 3, 2014 - 08:08 AM
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We like to have a little fun on Fridays during Good Morning Washington and today's theme is obvious with the Nationals playoff game.  I did some digging to find out how the weather might impact the game and came up with some fascinating information.

We all know weather can impact the players and their ability to handle the ball. Some of the obvious include rain and wind.  But, did you know that air pressure, temperature and humidity all affect how far the baseball can travel?

(Weather and Baseball)

Let's start with temperature. If we don't consider how the cold or heat makes the player feel, having hot weather can make for better action.  When the air is warm, the air expands and rises. This lowers the density of the air and allows the ball to go faster and farther. Temperatures during the game today will be in the mid to upper 70s and in the 60s on Saturday.

(Temperatures and Baseball)

Nationals Park is located in beautiful Washington, D.C. right along the Anacostia River.  Seems like a great central location, not to mention a pretty view. Here's a snapshot from Google Earth.

(Google Earth)

However, whoever decided to build the ballpark there probably didn't consult a meteorologist. Why, you ask? When considering atmospheric pressure, it's not ideal. The park sits at sea level where there is friction at the surface and pressure is higher. When air pressure is lower, a baseball can travel at a greater distance. A baseball hit at the exact same angle and speed at Coors Field in Denver, Co., (the mile high city) may travel 20 to 40 feet farther!

(Baseball and atmospheric pressure)

Considering the humid air today with milder temperatures and the colder, breezy day expected on Saturday evening, weather and physics tell me the Nationals are hitting some home runs today! For the updated forecast for both games, check out our other blog here. If you're interested in more information on weather and baseball there is a great interactive website here by NASA that is especially cool for kids.

 

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Nationals Game 1 and Game 2 weather forecast

October 2, 2014 - 02:32 PM
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With the Giants taking care of the Pirates last night, times have been decided for the Nationals first two home games. The first game is Friday at 3:07pm. Here in the weather center, we have been keeping a close eye on the forecast as a strong area of low pressure and associated cold front begins to take shape over the central part of the country. Luckily though, the forecast is still looking rather nice at this time.

Nationals Game 1 weather forecast

Friday looks to start much like the past few days, with morning fog and some sunshine by Noon. For the start of the game, expect comfortable temperatures in the mid 70s under partly sunny skies. Clouds may begin to stream in ahead of the cold front late in the game but conditions will still be comfortable and dry with temperatures falling into the lower 70s towards the end of the game. It may even be a little breezy at times with winds out of the southeast around 10 mph.

The frontal boundary should pass through the area Friday night into Saturday morning. At this point we think rain will become more likely closer to bedtime and continue to be possible through the predawn hours. Rainfall amounts around a quarter of an inch will be possible.

Nationals Game 2 weather forecast

Behind the cold front, Saturday will feature cooler temperatures and breezy winds. The game Saturday isn't until 5:37pm, so hopefully the winds will diminish some, but temperatures will be chilly regardless, starting in the mid 60s. By the middle of the game temperatures should be around 60 degrees and are expected to fall into the 50s by the end. Be sure to wear something warm! I'll tell you one thing, I am super excited to once again be experiencing baseball in October in D.C.  Go Nationals!

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Fall Fog

September 30, 2014 - 10:29 AM
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Photo: Sue Metzger
Photo: Sue Metzger

Visibility was poor in parts of the metro this morning as fog blanketed the region, mainly east of the blue ridge stretching up to the beltway.  Dulles Airport saw some of the worst of it as shown in this picture from Mike Ellis.

Photo: Mike Ellis

Temperatures cooled just enough overnight with light wind and moisture trapped at the surface underneath a weak area of high pressure.  It was a recipe to slow down the morning commute for many.

There were also some delays reported at Reagan National due to low ceilings. Here is a visible satellite image showing the fog wedging up against the mountains. 

Visible Satellite at 10a.m.

 

And check out this amazing photo from Karen Moorhouse from Interstate 64 this morning at Rockfish Gap near Charlottesville, VA.  You can't even see the city below.

Photo: Karen Moorhouse

The layer of clouds and fog is shallow and should break some midday and this afternoon.  An approaching cold front will mix the atmosphere to help this process.  However, it will also bring some stray showers in the mountains later today, while the rest of us could see a shower overnight or early Wednesday.  The morning commute will likely be foggy in spots again.  Plan ahead and set the alarm clock a little early.

 

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Stunning Sunrises and Sunsets

September 27, 2014 - 04:56 PM
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I don't know about you, but I have seen some unbelievably vibrant sunrises and sunsets this past month.  My Facebook and Twitter pages have been inundated with these spectacularly colorful skies.  Check out a few of them here:

Lori Martin Photography
Lauren Bevington - Fairfax, VA
Tosin Fakile

 

So what causes these brilliant colors in the morning and evening sky?  It all has to do with the low sun angle and how much atmosphere sunlight has to pass through.  A phenomenon called 'scattering' pretty much sums up the colors we see in the sky. 

The reason the sky is blue is because of Rayleigh scattering. See the graphic below.

Sky and Telescope

Notice the colors on the left (blue and violet) have a much higher percent of scattering compared to orange and red colors.  Sunlight is scattered among the molecules (oxygen, nitrogen, water vapor) in the air.  Since these molecules are very small, they scatter the shortest wavelength of blue.  This is why the sky is blue. 

University of Wisconsin, Madison.

At sunrise and sunset, the sun is lower in the sky and has to pass through more of the Earth's atmosphere (see image above).  If the path is long enough, the blue and violet light scatters out of sight allowing the longer wavelength colors to reach our line of sight.  This is why we see the rich reds, oranges, yellow, and pink hues during sunrise and sunset. 

Eileen Whelan

Fall and winter tend to have the most spectacular sunrises and sunsets because of the lower sun angle.  Also, much drier, less polluted air is overhead which allows more colors of the spectrum to make it to our eyes.

You've probably noticed that some of the most magnificent sunrises and sunsets have some clouds present.  Mid and high level clouds act to accentuate or enhance the colors.  Clouds also contain water molecules that further the scattering process. 

Jen Johnson

The StormWatch7 weather teams welcomes you to upload your sunrise and sunset photos to our Facebook page.  You can also tweet your photos or email them to us!  We love to share your photographs via social media and television. 

Enjoy nature's art in the sky over the next few months!

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Some Heavy Rain Moving into the Washington D.C. Area

September 24, 2014 - 01:38 PM
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Finally! As we edge towards the end of September (can you believe it?), we are finally seeing a good chance of rain headed towards the Washington D.C. area. It certainly looks like rain as those clouds hang thick for your Wednesday with temperatures only topping out in the upper 60s/lower 70s.
An area of low pressure will continue to travel up the eastern seaboard today and through the day tomorrow bring a good amount of rain with it. 

ZZZZZ

 With high pressure sitting to the north and low pressure inching its way up from the south, oceanic moisture will continue to stream in to the Mid Atlantic. This will also create a fairly persistent easterly wind through Wednesday afternoon and into the overnight hours moving northeast at 10-20 mph along I-95 and eastward . The winds will be responsible for some of the coastal water levels to rise around the area, resulting in some minor coastal flooding during high tide.

Most of your Wednesday afternoon will be dry, however, rain will build in from the south to the north after about 5p.m. I am just expecting light rain during the evening hours with the heaviest rain falling during the overnight hours and through the first part of tomorrow morning as that high pressure to the north breaks down and more moisture moves into the region-resulting in heavier rainfall.

ZZZZZ

 A flood watch has been issued for the Greater Washington D.C. Area from 6p.m tonight until 6 a.m. Thursday morning but the National Weather Service may have to extend and expand the flood watch as we get closer to the event.

Considering this is a coastal system, much of the heavy rain will be concentrated along I-95 and eastward but that does not mean that areas to the west are in the clear. We are still expecting some rain west of the D.C. area but the totals may be much less.

ZZZZZ
From the Blue Ridge Mountains moving east to the Bay, accumulated rain totals will gradually increase. Washington D.C. area could expect around 1.00” while just to the east could expect 2.00”+.

Good news is that we need the rain! Ronald Reagan National Airport is running about 2.38” below normal for the monthly rain rate in September. Baltimore-Washington Airport is just over 2.00” below normal for average rainfall in September and Dulles International Airport is 2.79” below normal for the month of September as well!

Dry conditions continue to expand through Virginia as well with a lot of our counties measuring “Abnormally Dry” via the U.S. Drought Monitor.

ZZZZZ

U.S. Drought Monitor shades areas in Yellow that are “abnormally dry” as of September 16th.


If you are headed out to Nats Park tonight for the game against the New York Mets, you might want to bring some rain gear. Again, I am just expecting light showers to spread into the region after 5 p .m. and through gametime. Good news is I am not expecting any thunder or lightning with this system so hopefully the game will go on, despite the showery forecast.

ZZZZZ

As far as Thursday Night Football goes at Fed Ex as the Redskins take on the Giants, things are looking dry after a wet start on Thursday. If that low slows down, we could have some rain last through the evening hours but as of now, I am keeping things dry for tomorrow evening. Temperatures will drop through the 60s during game time but if you are headed out there early for tailgating, just be prepared with some towels (to dry everything off) and maybe a light jacket that doubles as a rain coat. It will be a cool night at Fed Ex.

ZZZZZ


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Space capsule capture this morning means better forecasts on earth

September 23, 2014 - 07:45 AM
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If you watched Good Morning Washington on ABC 7 today, you saw it live when the International Space Station captured the SpaceX Dragon Capsule. Cool images, you might say, but this is its fourth trip to supply the ISS. What's new? Actually, a lot. 

(30 meters from ISS - NASA Photo)

It's not just supplies and new science experiments this time around. On board the space craft is a new instrument that can measure ocean surface wind speed and direction. It's called RapidScat and will help improve weather forecasts, monitor hurricanes, and help observe interactions between the atmosphere and ocean to better understand their influence on the Earth's climate.


(RapidScat - NASA)

There has been a lot of buzz this year about a possible El Niño developing this fall or winter. The RapidScat can detect changes in ocean winds which can help monitor large-scale patterns like El Niño and La Niña. 

The successful capture of Dragon took place a bit ahead of schedule at 6:52 this morning. Here is a picture from SpaceX.

(Dragon Capture by ISS - SpaceX)

It took Dragon two days after lift off from Cape Canaveral to travel and dock to the ISS and will stay there until Mid-October.

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DC Fall Foliage Season Just Around The Corner

September 21, 2014 - 07:24 PM
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A wet September and October is ideal for bright fall colors. On the contrary, a drier than average late summer and early fall accelerates the leaf-changing process and the leaves tend to fall before the best color can be reached.

In Washington, while the year has been wetter than average, September has been mostly dry. Rainfall deficits are 2.0 to 2.50 inches inside the Capital Beltway. Central Virginia is also a bit drier than average with rainfall deficits around 2.50 inches as well. The Interstate 81 is in better shape with Hagerstown, Md., and Martinsburg, W.Va., in a 0.80 to 1.10 inch deficit.

Therefore, the dry trend does not bode well for an exquisite outbreak of luscious colors. Looking ahead, the upcoming pattern doesn’t favor rain until the end of the month.

What else helps to create deep oranges and yellows, etc., in the fall foliage? Warm, sunny days followed by crisp, cool nights with temperatures above freezing. Therefore, high temperatures in the 60s and 70s with lows in the middle 30s to around 50 degrees.

peak fall foliage

The sharp temperature changes keeps sugars from reaching the leaf’s root system so the sugars are converted into pigments that produce the brilliant colors.

The upcoming pattern, while dry, favors a nice swing in temperatures with highs in the 70s and lows in the 50s. This trend is also right on par with climatological averages in the nation’s capital. A biting frost or early hard freeze is not on the near horizon in the western suburbs, which will help bring out the wonderful colors.

Frequent rain and wind events in the fall will bring the leaves down before they reach peak color as well.

peak fall foliage

So, while the month will likely end drier than average, the soggy summer will hopefully pull through and the favorable temperature trend could be the icing on the cake to a picturesque fall!

Here’s a look at when fall colors typically peak in the region; the colors first appear in the Alleghenies by early October and then the foliage season migrates into the District by Halloween. The eastern shore is the last to see the best colors; here it’s usually a few weeks prior to Thanksgiving.

peak fall foliage

Want to know the full process of how the leaves change color? Check out this detailed fall foliage blog by Alex Liggitt on the transformation the leaves go through to become vibrant in the fall.

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Only A Few Days of Summer Left Before Autumn Begins

September 19, 2014 - 02:19 PM
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Enjoy this last weekend of summer - because it is going to feel more like summer here in the Washington D.C. area! Temperatures throughout this last week of summer have been running below normal giving us a little taste of Fall.  However, by the time we head into this weekend, temperatures will top out in the 80s for much of the region thanks to high pressure clearing out cloud cover and helping us boost into the 80s with a light southeasterly flow.

A cold front will cross the area Sunday which will give way to some clouds and about a 30% chance of showers in the afternoon and evening hours moving from west to east. This cold front will also sweep away any of the summer-like weather we have left and leave us with another spell of Autumn weather around the region.

This is happening right in time because the autumnal equinox arrives at 10:29 p.m. on Monday! People celebrate this moment across the world and really the precise moment is when the sun passes directly over the equator! This happens twice a year as you may recall (the "spring equinox" and the "autumnal equinox"). 

 

ZZZZZ

 

In latin, the word "equinox" means "equal night" --"equi" meaning "equal" and "nox" meaning "night". This signifies the equal parts of daylight and darkness.

However, this is not always so "matter-of-fact." The sunrise on Monday is 6:55 a.m. and the sunset is 7:07 p.m. This isn't exactly equal. In fact, we have to wait until Tuesday, the first full day of Autumn to get the full equal light-equal night. The sunrise on Tuesday is 6:56 a.m. and the sunset is 7:06 p.m.

My colleague Eileen Whelan summed it up correctly when she wrote:

"We have the atmosphere to thank for this oddity. Also, the definition of sunrise and sunset. Sunrise occurs the moment the tip of the sun can be seen on the horizon and sunset is the last minute the sun can be seen before it dips below the horizon. Also, keep in mind our atmosphere refracts, or bends, light, which makes it appear as if the sun is rising or setting earlier.

The true equinox occurs when the center of the sun's disk crosses the celestial equator and this occurs at 10:29 p.m. EDT on Monday, September 22. At the same time the equinox occurs in D.C., it occurs across the globe."

Either way, you won't notice a different from Monday to Tuesday, from Summer to Autumn. However, you will notice that the hours of daylight start getting shorter until the Winter Solstice which begins on December 21, 6:03 P.M. EST (which is also the darkest day of the year meaning the day with the least amount of daylight.

However, as we make the transition into Fall, it may seem a little cooler according the outlook by the Climate Prediction Center:

 

ZZZZZ

But, also according to the Climate Prediction Center for the 8-14 day outlook, temperatures may be a little on the warmer side!

 

ZZZZZ
So don't pack away those flip-flops yet for those boots. Fall is here to stay but bouts of summer may stick around until early October!

 

 

 

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Hurricane Isabel: 11 years later

September 19, 2014 - 05:00 AM
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Isabel made landfall along the Mid-Atlantic on Sept. 18, 2003. Photo: NOAA

Many of us remember enduring days - some weeks - without power. Flooding and downed trees and power lines were just some of the hardships faced after Isabel slammed into the East Coast on Sept. 18, 2004.

NOAA

Hurricane Isabel has gone into the record books as one of the most significant tropical cyclones to affect the Chesapeake Bay area since Hurricane Hazel in 1954 and the Chesapeake-Potomac hurricane of 1933.  Here are a images of Isabel's impact in our area.

Isabel Damage
Isabel Damage
Isabel Damage in Calvert County, MD

Isabel was the ninth named storm of the 2003 Atlantic hurricane season. It originated about 625 miles west of the Cape Verde Islands on Sept. 6, 2003. The storm tracked westward, gaining intensity and, at one point, reached Category 5 status with maximum estimated sustained winds around 165 mph. Check out Isabel's track:

NOAA

By the time Isabel made landfall near Drum Point, N.C. around midday Sept. 18, it was still a Category 2 hurricane with maximum sustained winds of 105 mph.

Isabel then tracked north-northwest, losing tropical characteristics, but still producing flooding rain and tropical storm force winds. Here's an image of the radar, as the center of Isabel tracked over North Carolina.

Wakefield, VA NWS

The copious amounts of rain, coupled with strong winds, tore down trees and power lines and even led to a few fatalities.

Locally, the Shenandoah Valley received 6-12 inches of rain. Between two and six inches of rain fell in western Maryland and eastern West Virginia, and the Baltimore/Washington region received a total of one to three inches of rain.

At the height of the storm, Reagan National recorded a wind gust of 50 mph.

NOAA

Unusually high storm surge accompanied the storm with some watersheds between six and feet above normal. The storm surge in the Chesapeake Bay and Potomac River reached the highest levels since the Chesapeake/Potomac hurricane of 1933.

USGS - http://md.water.usgs.gov/publications/press_release/2003/2003-10/

From emergency management reports, estimates of about 6 million customers lost power at some point during the storm in North Carolina, Virginia, Delaware, West Virginia, Pennsylvania, and Washington, D.C.

The estimated total economic loss from Isabel was about $5 billion, according to the American Reinsurance Group. With so many people affected by the tropical cyclone, it took a long while to fully recover.

Even with the advanced warning of the hurricane, thousands of people were impacted by Isabel.

Further information about Isabel is available from the National Hurricane Center, National Centers for Environmental Prediction, United States Geological Survey and the National Weather Service.

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Dry start to September in the D.C. area, dry outlook ahead

September 16, 2014 - 12:06 PM
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Over the past few weeks, a few locations saw some moderate to heavy rainfall from storms but they were highly localized. Here are some of the locations that have seen decent rainfall this month on our WeatherBug Network.

Monthly Rain and temps as of Noon Tuesday on our WeatherBug Network

Other parts of the area haven't been quite as lucky as of late, with official reports at the local observation stations capturing relatively little rain for the month of September. Officially, precipitation totals so far this month are running anywhere from 1" to 1.5" below normal. Unfortunately, the current outlook isn't going to bring appreciable rainfall anytime soon.

Rainfall by the numbers this month and for the year

Above is a look at how the region is faring as far as precipitation this September. Dulles Airport is struggling the most, with only 0.21" of rain in the first 16 days. The observation station is running over an inch and a half below average for the month.

BWI Marshall has been the closest to average precipitation but is still running around an inch below for the month.

Maryland Drought Monitor

As far as the drought monitor is concerned, the region isn't even abnormally dry. This may change over the next week or two, but looking at the statistics for Virginia and Maryland, there aren't any regions with drought in Maryland and only a few abnormally dry spots south of D.C. in Virginia.

Virginia Drought Monitor

Much of this is due to the fact that the region has such a big surplus for the year and stayed around normal over the summer months. Precipitation is still running nearly 6 inches above average for the year at Reagan National and over 9 inches above average at BWI Marshall.

QPF today through next Tuesday morning from the WPC

The forecast looking ahead over the next few weeks doesn't look to good for rainfall chances in the D.C. area. The WPC forecast above only brings about a chance for light rain over the next week, and other modeling continues to depict dry conditions even through next week. A few showers may be possible with a cold front next Monday into Tuesday, but beyond that the region may not see decent rainfall until after the following weekend of the 27th and 28th. We'll of course keep you up to date with our latest 7-Day Forecast.

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Sunday Night "Mysterious Flash of Light" in the Sky

September 15, 2014 - 07:53 AM
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Many reports have been coming in of people in the D.C. region seeing a bright flash in the sky last night. It happened just before 11 p.m. Eastern Daylight Time. Most reports on the American Meteor Society website are described as a bright white or yellow flash that lasted around one second. Here is a map of all of the reports:

(Meteor Sightings via American Meteor Society)

So, what was it? Most likely, it was a meteor. Meteors are pieces of rock, ice and dust, usually from a comet, that explode and burn up as they enter the Earth's atmosphere. There are two meteor showers taking place in the month of September. First, the Southern Taurids, which are active for two months from Sept. 7-Nov. 19th. According to the American Meteor Society, they tend to produce few "shooting stars" but can be rich in fireballs and often responsible for an uptick in fireball reports to the society's website. In addition to the Southern Taurids, the less known Piscids will be near their peak in September and continue through October.  Check out this article from In-The-Sky.org. Let us know if you saw anything: Just go to our Stormwatch7 Facebook page and leave a note. 

Update:

This video was taken from Jesse Ferrell who works for Accuweather in State College, PA. You can see how the fireball completely lit up the night sky.

Here's another look at the meteor from Jeremy Settle, Assistant News Director at News 12 in New Jersey.

 

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Roller coaster temperatures this week, strong storms possible Thursday

September 9, 2014 - 08:46 AM
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The weather picture is rather complex this week and we've got a little bit of almost everything in the forecast, even SNOW! (Ok, the snow is for Canada, Montana and maybe the Western High Plains, but now I have your attention!)

Low pressure has been keeping us cloudy and cool in the Mid-Atlantic since Sunday night. The high in D.C. yesterday was 77 degrees and with mid-upper 70s again today, it will be the coolest stretch of temperatures since late May (thanks to Ryan Miller for that nugget). All of this is happening on the average last date of 90 degrees at Reagan National.

 

(This Afternoon)

 

As the low pressure system departs tonight, our focus turns to a potent cold front that is currently in the Midwest.  MUCH cooler air is coming in from Canada behind it where they have been seeing some snow!

 

(GFS Model showing possible snow in Western NE Thursday)

 

The cold front drops through the plains and spreads toward the east. Check out the chilly nights ahead for our friends to the north!

(Flirting with Freezing Thursday AM Midwest)

Notice on that forecast model that as the cool air invades the nation's mid-section, warm air will be drawn in ahead of that front it the east. It will be muggy in D.C. Wednesday as it warms up to around 80 and by Thursday we reach the top of the roller coaster with  highs back in the mid to upper 80s. Here's a look at highs from the North American Model.

 

(NAM Temperatures Thursday)

 

By the time it arrives in the D.C. area, this storm system will already have a history of producing severe weather. Today it will hit the Midwest and then the Great Lakes/Ohio Valley on Wednesday. By the time it reaches us, much of the energy will be to the north. However, with a strong jet in the upper levels of the atmosphere, the thunderstorms that develop over the D.C. region could produce damaging winds Thursday afternoon/evening. 

 

(Storm Prediction Center Severe Outlook Thursday)

 

This all should pass us overnight on Thursday and stall in the southeastern U.S. That puts us in the cool sector with 70s again for highs and overnight lows in the 50s even inside the beltway. The core of the cool air evades us, but it sure will feel like fall. In addition, a reinforcing cold front comes in on Saturday (bottom of roller coaster) with a few showers. Expect below average temperatures into next week.

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