From the ABC 7 Weather team

Archive for September 2012

September 11: Weather almost the same 11 years later

September 11, 2012 - 04:15 PM
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Here in Washington, in New York, and much of the country for that matter, woke up to a beautiful, cloud-free, blue sky this morning.  We also woke up remembering the great national tragedy of 11 years ago and you may have thought how eerie it was to have almost the same weather. The weather pattern is almost a duplicate of the weather 11 years ago today. Here is the national weather map from an article in Weatherwise magazine by meteorologist Sean Potter. 

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Here is the national weather map today. 

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And look at the satellite view from the GOES satellite 22,000 miles above us. 

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And this afternoon's satellite image of the DC region from the NASA AQUA satellite 400 miles up. 

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Yes, a bit eerie, but maybe fitting that the weather itself causes us to pause once again, to remember that terrible day, reflect, and think of so many who lost their lives on September 11.  It's also important to look back at the days, weeks, and years that followed and thank the men and women who help give us the freedoms and lives we have today, to enjoy a beautiful day such as today.  

 

 

 

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Saturday Severe Storms: Were You Informed?

September 11, 2012 - 05:00 AM
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What a beautiful Saturday morning and early afternoon, it was. It was hot and humid, but it was quite breezy and it was mostly sunny. If you hadn't listened to the entire weather forecast for Saturday, you may just assume it was going to be a sunny and hot day. Well, as we all know now, that wasn't the case!

ABC7 reported the potential for severe weather for Saturday afternoon earlier in the week. Thursday and Friday ABC7 meteorologists Bob Ryan, Doug Hill, and Adam Caskey showed this severe threat graphic (below).

Severe Storm Risk Graphic

Did you see it?  How helpful was it in preparing you for what was to come on Saturday afternoon?  The sunny, breezy, and hot weather at 1pm Saturday in D.C. turned to dark, stormy, and gusty by 3pm.  Winds gusted upwards of 70mph and a few tornado warnings were issued by the National Weather Service (even though no tornado was confirmed). 

Take another look at the above graphic.  What does it tell you?  Does it give you an idea of the greatest threats of the storms?  The yellow wind bar is the highest, since damaging wind gusts were anticipated.  The hail and flood bars were relatively low with a slightly higher risk of a tornado.  That is what ABC7 meteorologists were trying to convey with this graphic.

Emphasis on communication of the weather forecast between the meteorologist and the viewer is critical... what decision will you make based on the information you're given? 

Meteorologist Bryan Norcross wrote a blog recently linking the "mangled message" individuals receive after watching/listening to a weather forecast and what decisions they make based on the weather forecast.   

So how informed were you for Saturday's storms?  Give us some feedback in the comment section below.  Is there something we could have done differently?  We want to hear from YOU!

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Wow, a quiet D.C. weather pattern coming up?

September 9, 2012 - 06:42 PM
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What a busy summer weather pattern! The derecho, record heat, bursts of downpours and severe storms that have caused quite a ruckus in the D.C. Metro area. Guess what is in store now for the next week or so? An unusual change we’re not acclimated to…. a quiet weather pattern.

The constant barrage of rain and storms has also chipped away at the rainfall deficit. In the latest report issued by the weather service, the yearly rainfall deficit as of Sunday was down to 6.25 inches after being up to 8.44 inches just a month ago. Two inches of rain has been made up for in the last month from showers and storms at Reagan National Airport.

The cold front that plowed through Saturday evening has made sweeping changes in our weather. Temperatures, and more importantly, dew points have dropped to very comfortable levels.

The strong high pressure that is building in late this weekend will have a ripple effect well into the next work week. As a matter of fact, it should remain firmly in control across the Northeast and Mid-Atlantic through early next weekend! This will spell bright, sunny days and clear, cool nights with no rain or storms!

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    Here are some fun weather facts to share with your friends:
    •The last time the District had a stretch of 4 days with low temperatures between 58 and 60 degrees (the forecast for the next several nights) was June 5-8th. 
    •The last stretch of 7 days without measurable rain (not even a trace) was November 1-9, 2011 (forecast is for bone dry weather through next Saturday!)
    •Fall is arriving quickly. We lose 14 minutes of daylight through next Saturday, Sept. 15th and 1 hour and 14 minutes of daylight in the next month.

Be sure to get the latest forecast on ABC7 and WTOP Radio. Enjoy the fine spell of weather that we really deserve!

 

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Severe thunderstorms in the D.C. area Saturday

September 8, 2012 - 01:45 PM
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Greatest Storm Risks today

A Severe Thunderstorm Watch is in effect until 10pm.

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5:22pm:  Severe weather has ended across the viewing area and now the cooler air settles in.  A few showers will still be possible early this evening, but the severe threat is over for the night and the next 7 days.  

4:49pm: Storms have moved across the Chesapeake Bay onto the Eastern Shore but some still remain through Southern Maryland. Heads up to residents in Charles, Calvert and St. Mary's Counties over the next 45 minutes.

4:34pm:  Tornado warning canceled for for Anne Arundel county.  Main threat is the torrential rain and damaging wind gusts up to 70 mph.  Hold off travel towards the Bay Bridge.  Much quieter in D.C. with temperatures now in the 60s.

Live Super Doppler

4:08pm:  New TORNADO WARNING until 4:30pm for Anne Arundel county.  Heads up if you're along Rt. 50 -- extremely dangerous wind gusts and possible rotation within this storm cell.  Wind gusts could exceed 70mph and power outages are likely.  

4:05pm:  Flash Flood Warning in effect for the District of Columbia until 6:30pm.  Torrential rain will cause flash flooding.  Storms still racing East and moving towards Eastern Prince Georges and Anne Arundel counties.

3:59pm: Tornado warning canceled for Montgomery county, but remains in effect through 4:30pm for Prince George's county. 

3:36pm:  Meteorologist Devon Lucie reports power out in Reston, VA with wind gusts to 70mph.  Very strong line extending through Fairfax county.  Tornado warning remains in effect through 4pm.  Head inside if you're in the path of this line of storms.

Live Super Doppler

3:27pm:   TORNADO WARNING FOR THE CITY OF FAIRFAX until 4pm.  Take cover now if you're in the path of this storm cell that is moving East at 45mph.

3:08pm:  Live Super Doppler at 3:05pm.  Storms starting to pick up in speed, as they move through Leesburg, Aldi, Marshall.  Expect wind gusts upwards of 60mph with torrential rain and some lightning.  More storms popping up now over Southern Frederick county.   The main line of storms extending through Fauquier county to Northern Prince William co. will continue to track East.  D.C. to expect storms within the next 2 hours. 

Live Doppler as of 3:05pm

2:47pm: Be sure to have all of these numbers handy later on in case there are power outages. A very dangerous line of storms is heading over the Blue Ridge as we speak.

2:38pm: Here's a look at the tornado warned line of storms. Watch out I-66 cooridor west of the Blue Ridge.

Strong storms west of the Blue Ridge

2:30pm: A Tornado Warning is in effect until 3:00pm for Shenandoah, Warren and Frederick Counties in VA. This storm appears to be headed towards Strasburg in VA near the I-81 and I-66 merge areas.

2:17pm: A Severe T-Storm Warning is in effect until 3:30pm for the Shenandoah Valley from Winchester to Rockingham County, VA.

2:15pm: Highest rainfall totals so far are 0.85" in Purcellville, VA, 0.81" in Myersville, MD and 0.78" in Martinsburg, WV.

2:06pm: Clear skies are allowing for sunshine out ahead of the thunderstorms leading to a bit more instability. This is not good for the afternoon forecast in D.C. A nice line is still forming out over the Shenandoah Valley heading to the D.C. Metro by 5pm.

2:00pm: A new Severe T-Storm Watch has been placed in effect south of the D.C. area including Richmond south through Raleigh and Charlotte, NC. Heads up if you're heading to the NASCAR race tonight under the lights. The watch goes until 10pm tonight. 

1:57pm: Numerous thunderstorms are beginning to fire and intensify west of I-81 in the Shenandoah Valley. They are expected to become severe as they push east towards the D.C. Metro. Damaging winds will continue to be the biggest threat in these new storms.

1:49pm: It looks like a tornado hit Queens, NY earlier today per SPC storm reports. I am not sure if the video below is legit, but thought I would throw it in there anyways. It appears like it may be real but feel free to comment if it's not as it's really hard to get verification from a youtube video.

View more videos at: http://nbcnewyork.com.

1:39pm: A line of storms continues to stretch from Carroll County in Maryland southwest to Northern Loudoun County in Virginia moving towards Point of Rocks. Damaging winds are still possible in this line of storms.

1:32pm: Check out the sky in Frederick County from one of our WeatherBug cameras. Pretty nasty looking out there!

1:28pm: Already one damaging wind report into the NWS with trees down in Washington County, MD

1:17pm: A line of severe thunderstorms is moving into Frederick County in Maryland, bringing with it the chance for damaging winds and heavy rainfall. A Severe Thunderstorm Warning is currently in effect until 2:15pm for Frederick, Washington and Carroll Counties in Maryland.

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Severe Weather: Now likely Saturday in D.C.

September 7, 2012 - 09:45 PM
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9:45 Update- from Bob Ryan- Alex's blog below still shows all the reasoning why we are now likely to be under severe watches and warnings Saturday afternoon.  There are watches out across parts of the Midwest until 3AM and likely will be more later tonight.  Look at the latest NASA GOES image 

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of the storms exploding across the Midwest.  One of the simulations of the weather we really look at is the ensemble of many "models" and that is also showing a line of strong storms coming through Saturday about 5PM

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">Courtesy PSU  Eyewall page

and we know the cold front coming will bring a dramatic change to the air.  So the combination of everything we are looking means there is a risk of severe storms Saturday, the highest risk in the DC area is 3-10PM 

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so stay informed and don't take any chances Saturday afternoon.  If you hear thunder, you are at risk of being struck by lightning.  Stay safe and we'll keep you posted

 

 

Let's get this out of the way first...this week has been downright brutal. With dew points in the 70s through the majority of the week, the humidity levels have been off the charts, and showers and precipitation have been common occurrances through the week. Now we end the week with 90 degree temperatures, but big changes are only 24 hours away.

A strong cold front is beginning to take shape over the Midwest, with a few severe thunderstorm warnings already out ahead of the front issued over Illinois and Indiana. That system will advance quickly through the day towards the Ohio Valley, where it should be located tomorrow morning. Below is the Storm Prediction Center's Moderate Risk for severe storms outlook. Our region is squarely in the risk area which extends from the NC-SC border north through the entire Northeast.

SPC Thunderstorm Outlook for Saturday

When to expect it? The timing for severe weather appears like it will be somewhere between 3 p.m. and 8 p.m. Saturday, though it should be even later east of town. With that being said, the beaches may not experience bad weather until the overnight hours, which would be good for beachgoers!

Simulated Reflectivity 5pm Saturday from the 4km NAM

What are the severe threats? As far as the type of severe weather, at this current time the thinking is for damaging winds as the primary threat. The thought is a line of thunderstorms will be ongoing during the morning over the Ohio Valley then cross the mountains and move into the D.C. area during the afternoon.

I do have to say that an isolated tornado may not be out of the question, as there is enough shear to support it. Though we are not anticipating an outbreak of tornadoes by any means, the chance for one or two is there. If a line of storms sets up, there is the chance for rotation within the line, but at this time I do not think there will be a huge threat of discreet supercells out ahead of the front. The best chance for supercells and potential tornadoes looks to be through eastern Pennsylvania, New Jersey and New York, which was why the risk outlook was upgraded to moderate.

Storms should push east through the late evening hours tomorrow, giving way to cooler temperatures, lower humidity and clear skies. The forecast for Sunday through early next week returns the D.C. area back to the 70s to near 80 degrees. get ready to get back outside!

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Rain Today : How Did That Happen?

September 6, 2012 - 05:39 PM
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OK I admit it.  My forecast late yesterday of a chance of a few showers was a bust.  Look at today's rains around the DC area.. The rain gauge at Ocean City is flooded and must be broken. 

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Yesterday there was a weak weather front near us and the air was super humid.  Look at the surface map from last evening. 
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What looked like just a little weak wave coming our way, got stronger overnight and the large area of rain spread in during the early morning hours and even led to some Flash Flodd warnings.  Not the greatest forecast I have ever made and here is a recap of what happened.

 

 

Promise to make today's forecast more accurate :>)

 

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90s in September?! How Long The High Heat Could Last

September 6, 2012 - 05:00 AM
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It was a hot summer!  July 2012 was the hottest month ever recorded since U.S. weather records began in 1895.  This July was also the second hottest month in D.C.  Reagan National, as of September 5th, has had 52 days with highs 90° or higher. 

90 Degree Days, So Far, In 2012

So, now we're into September - the start of meteorological autumn.  Now, if you're like me, you sometimes forget that with the flip of the calendar month, the temperature doesn't magically drop for it to instantly feel like fall.  I got the memo when I stepped outside on the first day of September and realized it was 95°!  

The average high in the beginning of September is 84° in D.C.  By the end of the month, the average high is 74°.  Even though the 95° high Reagan National reached on September 1st is about 10 degrees warmer than average, it's not anything unusual.  Take a look back at the past 10 years. 

The latest we've had a high over 90° in September was back in 2010.  September 25th got to 93° - boy do I hope the 90s don't last through the end of September!  Can you tell I'm ready for fall?  Five out of the last ten years have had 90° highs in September.  On the flip side, look at 2010!  September 2010 had no 90° days and the last 90 degree day that year was on August 4th!

The 2012 90 degree day counter continues.  I think we're in for at least two more to round out the work week. 

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Isaac: Did it go away or might It become Nadine?

September 5, 2012 - 04:34 PM
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Isaac was a terribly destructive storm with flooding rains from the Gulf to the Midwest.  What was a cluster of thunderstorms on one of the bands of Isaac as it slowly broke up this weekend has now drifted south into the northern Gulf of Mexico.  Check out this loop from the University of Wisconsin  and this latest image of the cluster in the Gulf from NASA GOES project.

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Another loop from the folks at UM Space Science and Engineering Center shows the circulation at about a mile high in the atmosphere from Isaac's hit on Louisiana until today maintaining an identity. So I would say it's still a bit of the "ghost" of Isaac that has now moved into the Gulf.  The latest from the Tropical Prediction Center....

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 ....has this thing (maybe we should name it "Dracula" if it becomes a tropical storm again) with a 40% chance of being named.  If it becomes a tropical storm, it would become Nadine,  Chuck Berry would probably like that but sure not folks at any risk in the Gulf states where the water is still about 85° with plenty of energy for storm formation.

 

 

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Tropical Storm Leslie, Michael Path: Storms no threat to U.S.

September 5, 2012 - 04:01 PM
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With the remnants of Hurricane Isaac continuing to bring plenty of moisture and the threat of more heavy rainfall to the D.C. area, I wanted to try to put your mind at ease that the U.S. shouldn't see any other tropical systems soon. There are still two systems in the Atlantic with Tropical Storm Leslie and now Tropical Storm Michael, but they pose no threat to the United States. Not everyone will be as lucky however.

Forecast Track for Tropical Storm Leslie

Above is the forecast track for Tropical Storm Leslie from the National Hurricane Center. The track pushes the storm north towards Bermuda and intensifies it into a hurricane. If you or someone you know is headed to Bermuda later this week, your plans may be changing. This may even be a strong hurricane by the time it approaches Bermuda.

Forecast Track of Tropical Storm Michael

Next there is Tropical Storm Michael, which really poses no threat to land whatsoever and is expected to remain weak through it's lifespan. You have to like a storm like that!

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D.C. downpours halt city center

September 2, 2012 - 09:03 PM
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Photo credit: twitter@BoundaryStoneDC

The same weather pattern that brought heavy rain to the District Saturday, resulting in 1.64 inches at Reagan National Airport, the wettest day since December 7, 2011, produced slow-moving flooding downpours in the District again tonight resulting in flash flooding.

A shower first blossomed over the Northwest part of the city just after 7 p.m. then grew in intensity, producing rain rates of 2 to 3 inches per hour.

Parts of Rhode Island Avenue, Florida Avenue and 1st and 2nd Streets were under water while the downpours flooded parts of the Metro.

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(Photo credit: twitter@BoundaryStoneDC)

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Water flooding the Howard University stop on the Metro’s Green Line (Photo courtesy of @AnaSantosPhoto)

Just before the rain ended, totals were up to 3 inches in Northwest. Here are other top rainfall totals from WeatherBug Stations.

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Even though the rain is subsiding, runoff will continue as will the flood hazards. Keep in mind it only takes 6 inches of running water to stall out a vehicle and cause you to lose control on the roadway. A foot of water will float a car away. It’s even more difficult to spot flooded roadways at night, so drive with extra caution.

These showers are quite intense but far and few between and compact in size that you may not know a roadway is covered in water until you approach it. Additional showers and storms will redevelop through early next week as Isaac's remnant low slowly moves closer. This will keep the flash flooding threat high.

Stay with ABC7 and WTOP for the latest on the ongoing flash flooding potential.

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