From the ABC 7 Weather team

Archive for April 2012

Red Flag Warning - what does that mean?

March 13, 2014 - 04:30 AM

A Red Flag Warning has been issued for the areas south and west of D.C including Fairfax, Loudoun, Prince William and Stafford counties to name a few and that may have some of you scratching your heads!


What the heck does this mean? A Red Flag Warning is a forecast warning issued by the National Weather Service to inform area firefighting and land management agencies that conditions are ideal for wild land fire ignition and propagation. Still wondering?


Here is the bottom line: there is an elevated risk for explosive fire growth. A combination of factors including extremely dry air (humidity levels are at levels typical for the Sonoran Desert in Arizona) and gusty winds (big-time bad hair day) and something called low fuel moisture (details here) all combined are a recipe for big-time problems.

Just over two years ago today, the Prince George's County Fire/EMS Department experienced the busiest brush fire day in the history of the department. Mark E. Brady, Chief Spokesperson of PGCFEMS has provided some important safety tips to help curb the fire potential:

• Dispose of smoking materials in an appropriate container and ensure they are completely extinguished. Do not discard these items into any open area as they may start a fire that will spread rapidly. Do not dispose of smoking materials out of your vehicle when traveling.

• Business owners and property managers should have appropriate disposable containers in areas where smoking occurs outside.

• Do not burn brush or trash ever without appropriate approval.

• We request that you not use outside grills or cooking equipment during these times. If you must, ensure you have some type of extinguishing agent nearby (water hose, bucket of sand, fire extinguisher, etc.)

• If you have fireplace ashes; you must put them into a sealed metal container placed on a concrete surface away from any structures. If possible - wait to clean your fireplace until this weather event is over.

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The F-4 La Plata Tornado; 11 Years Later (Photos, Video)

April 28, 2013 - 02:03 PM

On April 28, 2002, a "Moderate Risk" for severe weather was placed over the D.C. area by the Storm Prediction Center. Hours later, the region would be struck by one of the strongest tornadoes ever recorded in the Mid Atlantic and the strongest since another F-4 tornado struck Frostburg, MD just 4 years earlier. The tornado carved a 64-mile path through 4 Maryland Counties and was moving at an astounding 58 miles per hour which is nearly a mile per minute giving residents little time to prepare.

The event occurred on a Sunday, which ended up being lucky as one school was destroyed. As strong as it was, only 3 people perished that day. Another 122 people were injured and 344 homes or businesses were destroyed. Only 6 tornadoes at F-4 strength have been recorded further north and east of La Plata, MD. Keep in mind I am calling them F-4 tornadoes and not EF-4 tornadoes as the Enhanced Fujita scale was not used at the time.

What atmospheric conditions helped it form?

April 28 featured all of the ingredients needed for strong rotating thunderstorms. A strong jet stream existed over the northeast with winds in the upper-atmosphere around 90 mph while an additional 110+ mph jet existed to our west. As the D.C. area sat in the middle of these two jet streams we were in the prime place for rising motion giving a "coupled-jet structure". A cold front lied to the west of D.C. ensuring more vertical motion for thunderstorm initiation and skies cleared in the morning hours leading up to the event which allowed for maximum heating throughout the day.

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New tornado warning wording: 'Mass devastation likely'

April 30, 2012 - 05:00 AM

Even though the average lead (advance) time for tornado warnings has increased in recent years there are still instances, such as the Joplin, Missouri, tornado that occurred last May when 161 people were killed.

The average lead-time for the Joplin tornado was 20 minutes, but unfortunately because residents there experience tornado warnings so frequently they had become desensitized to them and didn’t take the appropriate action to be safe. This is common problem across the plains and the southeast (and concern for forecasters) where tornados happen frequently and residents almost tune out the warnings and sirens.

To combat this problem the National Weather Service (NWS) offices in Kansas and Missouri have begun an experiment testing new tornado warnings that are more specific and more descriptive, and the language more dramatic, as to the potential effects of the storms.

This experiment, called “Impact Based Warning,” is meant to grab the attention people who live in Tornado Alley and to “better convey the threat and elevate the warning over a more typical warning,” according to Dan Hawblitzel of the Pleasant Hill, Missouri NWS office.

The new warnings will include language like “mass devastation is highly likely, making the area unrecognizable to survivors” and “unsurvivable if shelter not sought below ground.”

The new warnings will be tested through November 30 and were first applied last weekend during a tornado outbreak that spanned  Kansas, Oklahoma, Nebraska, and Iowa.

The Kansas National Weather Service warnings that day included wording like “You could be killed if not underground or in a tornado shelter. Many well-built homes and businesses will be completely swept from their foundations.”

The initial results are encouraging, as a tornado did touch down and tore through a mobile-home park during the nighttime hours, but there were no fatalities.

After the experiment concludes in November it will be evaluated and possibly considered for more widespread use nationwide.

Chris Strong, the warning coordination meteorologist at our local National Weather Service office in Silver Spring, Md., said “Anything that adds detail or clarity to a warning is good. The more we can quickly relay specifics, and the level of danger, the more any given person will react with the proper response to any given threat.”

“We do in our area have the flexibility to change our warnings too when something hi-end occurs here. In fact, we can use things like 'tornado emergency,' 'large and devastating tornado has been confirmed,' several other ready to go phrases, or even freehand additional known details for more impactful warnings.”

“In the future, the NWS will be trying more and more of this (trying to delineate the level of danger in a dangerous situation). During the spring severe weather workshop, which other broadcast meteorologists and I attended in late March, we learned of other wording changes that are being made to our local severe thunderstorm and tornado warnings. These wording changes will be more subtle and will focus on removing unnecessary wording, clarity, and detail. Both of these changes are being made with the same goal to clearly communicate threat so that residents can take the appropriate action to be safe," he said.

Here’s an example of a standard Tornado Warning…
1023 PM CST SUN NOV 10 2002







Now here is an example of the experimental impact-based warning issued by the NWS in Wichita, Kan., a few weeks ago:

1041 PM CDT SAT APR 14 2012














I am interested to see what you guys think. Is this a good idea? Would these changes and the new wording get your attention? Would you be more likely to seek shelter or take the necessary actions if you saw the new wording? Let me know your thoughts.

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Bob and the Myth Busters

April 28, 2012 - 05:35 PM

Still some showers coming our way, but so what?

This is a great weekend to go to the 2nd Science and Engineering Festival at the D.C. Convention center.  You've still got some time to get out and check out the festival on Sunday. Here is what you'll have to look forward to:

I was there at 1PM Saturday with the "Myth Busters" on the main area. Here is a link with all the information

And make sure to bring your parents Sunday if you didn't get there today, the festival runs through Sunday.


Here I am at the main hall Saturday afternoon with Adam Savage and Jamie Hyneman the really inventive fellows who created and host Myth Busters.  We had about 1,000 young people (and parents) there today.  Lots of great questions for Adam and Jamie and lots of fun.  They ended with a video of some of their favorite explosions. 

It must be fun to have a show where you do get to blow things up.  But they sure made the point "Don't try this at home."  Here we are afterward when they're probably thinking, "He would look better with a duct tape hat"


I loved science and math when I was in school and to see how a nerdy kid grows up to be a meteorologist on TV, here I am next to my 9th grade science fair projects.


My project was future rockets. . .and this was before the launch of the first earth satellite "Sputnik".  Science is fun.  Some others you might see are Bill Nye The Science guy here with Adam:


and the storm chasers with this Doppler on Wheels. 


No tornadoes allowed this weekend.  Have fun and see you there!

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See astonishing photos of nature

April 27, 2012 - 01:06 PM

It doesn't look real, does it. But a Maryland photographer captures stunning images of nature - and more. See all the pics here.

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A Happy Cloud Weighs How Much?

April 25, 2012 - 10:17 PM

Ok, I know this is a trick.  Well, not really.  A fair weather cumulus cloud such as we saw yesterday . . . those "happy" clouds.... weigh about 100 thousand tons!! 

Cumulus Clouds

Even a big bull elephant weighs "only" about 5 tons or 10,000 pounds.  So what keeps all those elephants in the sky?  As you've guessed, a cloud is not quite as dense as an elephant.  An elephant, just like us, is primarily water and a cubic foot of elephant is about 60 pounds. 

Elephant.... This Is How Much A Cumulus Cloud Weighs???

But a cubic foot of cloud is mainly just air, but contains millions of microscopic droplets of water weighing only a few millionths of a pound.  The sun warms the earth and, as the day progresses such as yesterday, rising bubbles of air, even with just a little moisture, form those fluffy cumulus clouds.  The sunlight reflected or scattered off those microscopic droplets gives the clouds the white color and a bit gray on the bottoms, or bases, where the sun doesn't really shine so to speak. 

You can't really see those rising bubbles of air, but you can see large soaring birds, like hawks and vultures, slowly circling and rising in the bubbles or "thermals".   




  (A) Cumulus(1) warm surface  (2) rising thermal (3) sinking cool air

 Now imagine if an elephant could have the wingspan of one of those soaring birds . . .maybe elephants could fly.  Today, heavy clouds with the rain coming our way, but if the forecast works out, look for those 20,000 elephant versions back with us on Friday.




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More Spectacular Pictures, Like This One, In An Upcoming PHOTO GALLERY!

April 24, 2012 - 05:00 AM
Brett Noble Photography

You may remember this picture (above) we featured, as a Daily Eye Wonder, back in March.  Like it?  Well, there's more where that came from!  Stay tuned to our Storm Watch 7 Weather page, as we will feature a photo gallery from the photographer who captured this amazing image.  Brett Noble, a graphic artist, photographer, and weather enthusiast, tells us a little about himself. 

My name is Brett Daniel Noble, I was born in Lawrence, KS in 1973. I moved to Platte City, MO. in 1983 where I graduated high school in 1991.

Attended CMSU for a degree in graphic arts, which has been very rewarding. I really wished I would have gotten a degree in Meteorology, which is my ultimate passion. I do like to storm chase and always will.

I currently live in Rosedale, MD which is very close to downtown Baltimore. I am a freelance graphic artist and event photographer for MyWorks Photography. I specialize in weddings and events. Recently within the last 8 months, began photographing landscapes and nature. I find it more rewarding personally, maybe because it is new to me and I enjoy it more. Being a weather fanatic, it is really a lot of fun!

For my landscape photography I use a method known as HDR, better known as High Dynamic Range. I take anywhere from 3-30 images shot at different exposures to produce a more lifelike image. I use in camera bracketing that consists of 3 exposures generally shot at -2,0,+2 and repeat the process until I have enough exposures to merge into an interesting photograph. The more images the more animated the sky, water and colorful the landscape will look. I enjoy what I do and look forward to improving my landscape and nature photography. I do have my own style, but what photographer doesn't?

I also miss Kansas, mainly for the weather that occurs this time of year and of course family. I am pretty new to Baltimore so I am not sure what to expect. This has been quite the strange year for weather here, from what I understand. It can only get more interesting!

So, that is just a little about me and what I do. If you’re interested, you can friend me on Facebook. It’s always nice to meet new people in the area; I have also learned from the best photographers on Facebook, you know who you are.

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Rain for the World

April 23, 2012 - 05:46 PM

I did a quick (well a few minutes) calculation of how much rain the big East Coast storm produced.  How much rain water fell on just the land in the east (yes and some was sure snow) and how much fresh drinking water would that be.  Ready, here we go.  Look at the measurement from the NWS Advanced Hydrologic Prediction Service of the rain pattern for only 24 hours through Monday morning.  



To me looks it like 1.5" on average across the area from the Carolinas into New England.  That means that about 25 MILLION GALLONS of rain fell on every square mile of land.  I did a quick calulation that just the land area that got much needed rain in the east totaled about 300 THOUSAND square miles.  So if my math is correct that means that this one storm dumped 7.5 TRILLION (7,500,000,000,000) GALLONS of water on the east.  Look at the satellite picture I posted of this storm today and you can see the extent of the clouds and imagine how much water this one storm produced and much of it fell in the ocean.

 So how much is 7.5 trillion gallons?  Well (check my math again) it's enough to roughly give every man, woman and child on earth 8 big glasses of fresh water every day . . . for about 4 YEARS!!  Weather and nature pretty impressive don't you think.

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Snow at opposite ends of the season

April 22, 2012 - 05:02 PM

A low pressure off the Carolina Coast is moving north along the coast spreading rain across the District Sunday afternoon. The rain will amount to 1.00 to 1.50 inches by Monday morning. This will help chip away at the 5.14 inches deficit that started on New Year’s Day.

The biggest story with this storm system is the incredible heavy snow that will wallop the Allegheny Mountains/Laurel Highlands to start off the work week. As the low moves north, it will draw cold air in along its backside. Rain will change to snow from Interstate 80 south across western and central Pennsylvania and then into western Maryland.

While it’s difficult for snow to accumulate this time of the year, especially during the day as the sun angle often overcomes the cold air to keep the snow liquid form as it falls on grassy/street surfaces, this storm is rather unique.

The upper-level center of the storm will likely travel right up I-81 towards Hagerstown on Monday and then scoot north across the Pennsylvania Laurel Highlands during the evening and overnight. In the core of this upper-low, very cold air will be found just above the surface at 1,000 to 2,000 feet where temperatures will be in the lower 20s. While snow will mix with the rain in the valleys, at 1,000 feet, the Blue Ridge will likely pick up an inch in grassy spots while ultimately, the heaviest snow will likely fall nearest to the upper center as it crosses the colder elevations of the Allegheny Mountains Monday.

The fast downward momentum of the heavy snowfall rates near the upper-low will bring down those colder temperatures aloft, cooling bridges, overpasses, the grass and secondary road surfaces to allow for quick accumulation. In case you want to see snow here in the District, watch closely because a few snowflakes or ice pellets will likely mix in with the rain in the afternoon and evening as the upper-low makes its closest appearance!

The upper-level center will intensify the surface low, which will rotate inland across southern New England. The counterclockwise motion of air around the surface low will bring strong northwest winds across very warm Great Lakes, creating lake-effect snow. These snow bands will make it well into the Allegheny Mountains Monday afternoon into Tuesday. So, two mechanisms are at play for a significant mountain snow event…great upper-level forcing and the lake-effect machine.

Winter Storm Warnings and Winter Weather Advisories have been posted in much of western and central Pennsylvania into far western Maryland. Amounts will range from 1-2 inches in the hills outside of Cumberland, Md., to 3-5 inches in places like Frostburg and Westernport, Md., to a foot along the highest ridges of Garrett County, including Keyser’s Ridge and Backbone Mountain. Farther north, 9 to 15 inches will fall in places like Somerset and Johnstown, Pa., with up to 18 inches along I-80 in northern Pennsylvania.

Due to the heavy, wet nature of the snow falling on trees already well in bloom will cause widespread power outages and falling of limbs and branches. Those with plans to travel towards Pittsburgh or Morgantown should keep a close eye on the weather tomorrow and Tuesday. I-68 and the Pennsylvania Turnpike could turn treacherous with snowfall rates of 1-2 inches per hour causing whiteout conditions west of Cumberland, Md. Fallen branches could crowd secondary roads in rural spots.

The snow has been on the tail ends of the winter season. Record early-season snow hit the Laurels in October. Snow accumulated 1.2 inches in Philipsburg, Pa., 1.0 inches in Ebensburg, Pa., and 0.7 inches at Laurel Summit, Pa., on October 2nd. This was the earliest in the season accumulating snow has ever been recorded in the Pennsylvania Laurel Highlands! In the middle, the weather was mild and dry with above-average temperatures and below-average snowfall and now this early week whopper will put the icing on the cake!

Stay safe if your plans take you out to the mountains and check back to WTOP and ABC7 for the latest forecasts.


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Is the weather really more “extreme” these days?

April 21, 2012 - 05:00 AM

We can often forget those events that happened years ago unless they were epic, deadly or destructive. One thing stands out for sure though – it seems we are bombarded by records we hear on a day-to-day basis. Is there a reason for this?

Since the start of 2011 it seems we have been clobbered with weather statistics but for good reason….there were so many of them! A record 14 weather and climate disasters in 2011 each caused $1-billion or more in damages. What were these disasters? There were so many of them, including the Central U.S. tornado outbreaks in April, the historical Southern Plains drought and heat wave, record flooding along the Mississippi and two events that impacted the D.C. region; Hurricane Irene and Tropical Storm’s Lee remnant rainfall.


(Story Image: Hurriane Irene makes landfall in New York City. Courtesy of NOAA)

2012 is already in the record books for heat! The first quarter of the year was the warmest on record east of the Mississippi River, including right here in D.C., with more than 15,000 warm temperature records busted in March alone in the U.S.! In addition, the early March tornado outbreak in the Central U.S. was the year’s first billion dollar disaster.


“Subtle” records have gone unnoticed, however. Did you know it has been a record number of days since the last major landfalling hurricane along the U.S. Coast? Roger Pielke, Jr., professor of Environmental Studies at the Center for Science and Technology Policy Research at the University of Colorado at Boulder, Colo., noted in a blog late last year that as of December 14, 2011 there had been 2,232 days since a Category 3 or higher ranked hurricane made landfall in the U.S.


(Story Image Source:

With this in mind, we seem to find so many ways to “make” weather records. Given the wealth of weather data compiled at weather service offices and ability to store this information on computers, it’s easy to crank out weather statistics such as “the wettest January-March period” or “the number of consecutive days with temperatures at or above a certain degree.”

Therefore, while it appears we have so many extremes in our daily weather, we have more resources, more weather spotters and storm chasers to track severe weather and more efficient and faster ways of calculating records. It’s easy today to push the numbers through the computer and, for instance, find out the record number of consecutive days a city has gone without measureable rainfall for any given month or length of time (season, for instance) and identify it as a statistic to compare future dry periods!

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Coastal Storm Heading Our Way. How Much Rain This Weekend

April 20, 2012 - 10:30 PM

I feel like a broken record talking about how dry it's been, as of late.  Up until today, most of the area is about 5 inches below average for the year!

2012 D.C. Rainfall Deficits

Abnormally dry conditions persist across our area with parts of the Eastern Shore of Maryland under a severe drought.  Things are about to change, though.  The weather pattern is changing for this weekend and that means some significant rainfall for DC and many areas along the East coast.   Along with the beneficial rain will also come some much cooler temperatures, so get ready for a spring chill

Let me first explain what is going to happen this weekend.  A cold front will approach DC by mid-afternoon Saturday and will trigger afternoon showers and thunderstorms.  That's not the main reason we think it's going to be a wet weekend.  At the same time the cold front moves into the region, an area of low pressure will develop over the Gulf of Mexico and will intensify, as it moves up the East coast.  Here's a snapshot of the 18z GFS model at 2PM Sunday afternoon.

18z GFS

Notice the low sitting right off North Carolina and all of the precipitation around the Mid-Atlantic.  The low will continue to strengthen and move North (and eventually a bit farther West over New England), but will not only bring D.C. a steady rain on Sunday, but will also usher in some much cooler air.  In fact, temperatures on Sunday and Monday will only be in the 50s!  That's a bit of a change from the *near 90 degree temperatures we had on Monday

So back to the rain, just how much are we going to get?  Well, I think we could easily pick up an inch.  I wouldn't be surprised if some spots got closer to two inches.  The most rain will likely fall on the Eastern Shore of Maryland where conditions are even drier than right here in D.C.  Regardless, the bulk of the steady rain, associated with the coastal storm will fall throughout the day on Sunday and eventually taper off early Monday.  Here's the latest QPF from the HPC.


If you were hoping to get some yardwork done this weekend, well, my advice would be to get it done early Saturday morning.  Before the front arrives, we'll see a little sunshine, but it will be warm with temperatures in the 70s.  Then showers and storms will develop and then that coastal storm will bring us the rain, gusty winds, and cooler temperatures.  For all of you that did a raindance... it looks like it worked!

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Celestial Lights over the past 6 months (Featured Video)

April 20, 2012 - 04:30 AM

This video from Ole C. Salomonsen was made by filming many different solar storms which caused the auroras. Ole shot about 150,000 exposures in the past 7 months and used about 6,000 of them for this video using Canon DSLR's and wide-angle lenses. He also used a dolly and timing system from a company called Dynamic Perception to shoot these timelapses. Enough talk, check out his incredible video below.

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Goodnight, Irene

April 19, 2012 - 05:00 AM

Another hurricane name is added to the list of "retired names" -- Irene.  Irene becomes the 76th retired storm name.  You may remember Irene from last year, as it tore over parts of the Bahamas, the Dominican Republic, Haiti, and then traveled up the East coast.  The World Meteorological Organization's (WMO) hurricane committee will retire Irene from the list of tropical storm names in the Atlantic Basin due to the number of fatalities and cost of damage the storm caused.   Below is a satellite image of the hurricane over the Bahamas.


Tropical storm names are reused every six years unless, as in this case, the storm caused considerable damage and/or casualties.  As stated by NOAA, "Irene was directly responsible for 48 deaths: five in the Dominican Republic, three in Haiti, and 40 in the United States. For the United States, six deaths are attributed to storm surge/waves or rip currents,13 to wind, including falling trees, and 21 to rainfall-induced floods. Including flood losses, damage in the United States is estimated to be $15.8 billion".  


Damage From Hurricane Irene

Irene became the first named storm of the 2011 Atlantic Hurricane Season on August 20th and strengthened to a Category 3 hurricane by August 24th, as it passed Southeast of the Bahamas. Irene gradually weakened and made landfall in North Carolina, on August 27th,, as a Category 1 hurricane and continued to track North and East along the Delmarva Peninsula. On August 28th, Irene made landfall near Atlantic City, NJ and continued to bring heavy rain and strong gusty winds to New England.

NOAA - Hurricane Irene Track

Right here in D.C. we had to deal with a lot of rain and gusty winds.  Many people were without power for days and coastal flooding was a serious issue, as well. 

So you may be wondering, what name will replace Irene?  Well, the name is Irma.  That particular list of names won't be used again until 2017.  If you want to know if your name is on the list of tropical storm names for the 2012 Atlantic Hurricane season, here's the list:

Alberto      Florence     Kirk             Patty        
Beryl          Gordon       Leslie          Rafael
Chris         Helene       Michael        Sandy
Debby        Isaac          Nadine         Tony
Ernesto     Joyce          Oscar         Valerie

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FINALLY! An End to Our Dry Pattern? (VIDEO)

April 17, 2012 - 05:17 PM

We might get some showers on Wednesday, but meteorologist Devon Lucie shows how and why we might finally put a true end to the dry pattern this weekend!

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ABC 7 Cherry Blossom Photo Contest Winner (Photos)

April 17, 2012 - 04:09 PM

The Cherry Blossom photo contest was awesome this year with fantastic submissions by everyone. The winning submission was sent in by Phil Anctil, who captured a beautiful picture of the Jefferson Memorial and its reflection on the tidal basin surrounded by the blossoms. Check it out.

Phil Anctil's Winning Picture

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So Close, But We Didn't Make It. The First 90 Degree Day Contest Rolls On.

April 17, 2012 - 05:00 AM

For those of you participating in the First 90 Degree Day Temperature Contest, those of you who guessed April 16th, or earlier, didn't quite make it.  I'm sure, if you're anything like me, you were watching the DC observations very closely yesterday!  It was close, but didn't happen!  D.C. made it to 89°.  If the contest were for Quantico, Petersburg, Winchester, or Cumberland, you could have won!  Here were the official highs.

Highs for April 16, 2012

So if we had actually made it to 90° yesterday, would it have been the earliest 90 degree day in Washington?  Not even close!  Here's a look at the first 90 degree day over the past five years.

Earliest 90 degree day over the past 5 years.

We would have been 10 days late -- 2 years ago, we hit 90° on April 6th.  The earliest 90° ever in D.C.?  March 22, 1907.  Keep in mind, the average high for that day is 57°.  That's 33° warmer than average!!! 

Just two years ago, in 2010, we had the most 90° days on record.  67 days were 90° or higher!  The years with the fewest 90° days were back in 1886 and 1905 when we only had 7 days at 90° or higher.

So the contest rolls on.  Stay tuned.

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Summer warmth heads our way Monday; Pollen count soars

April 15, 2012 - 09:33 PM

For the fifth time this year, the high surpassed 80 degrees Sunday! The high temperature at Reagan National was 83 degrees; this is 16 degrees above average and only 6 degrees shy of the record high. What’ll make Monday the hottest day since September 14th when the high reached 87 degrees is an increase in southwest winds (which compress and warm off the Blue Ridge mountains), mostly sunny skies and the recent dryness.

Precipitation is 4.78 inches below average since the start of the year. Being in an abnormally dry spell (near the Bay a moderate drought) and not having any appreciable rain in excess of 0.25 inch since March 2nd, the ground is dry and heats up much more effectively than a moist ground. All these factors will likely push the mercury to near 90 degrees in the District. The warm, breezy weather could trigger brush fires as well.

Highs should come within 5 degrees of the following record highs for Monday:

Reagan Nat’l: 92 in 2002
Dulles: 91 in 2002
BWI: 90 in 2002

Sunday’s pollen count was 11.7; Monday will be even higher, with the primary pollen being maple, oak and ash. The dry winds won’t help matters either. It could be more like a manic Monday for allergy sufferers, so be prepared!

Now, where’s the rain? The same front that triggered the dangerous Central U.S. storms this weekend will move in our direction and likely move through around Midnight Monday. The problem is the best upper-level support will move into Canada as the front moves east, so the front will lose its identity by the time it reaches the Appalachian Ridge. We should see a band of showers fall apart across the western Maryland highlands with just a wind shift to the Northwest in the District late Monday as the front pushes through.

What about later this week? There is growing potential that a stronger storm system will push into the Mid-Atlantic Friday/Saturday and then wrap up the coast, bringing the potential for at least one-half inch of rain followed by cooler temperatures.


Of course, stay with the ABC7 Weather Team and WTOP for the latest forecasts this week! Stay safe and for allergy sufferers, temperatures will cool into the 70s Tuesday and then 60s by Wednesday.


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Snow and Hail This Past Wednesday? Not so Fast my Friend!

April 13, 2012 - 08:24 PM

First off, my apologies to Lee Corso for stealing his phrase made famous through his appearances on Saturday College Gameday. Did you spot some hail mixed in with snow with our windy/cold spring day this past Wednesday? Don’t feel bad if you answer yes, because even meteorologists mistake what actually fell with the snow fairly often as well.

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Gorgeous morning timelapse of the sunrise over D.C. (VIDEO)

April 13, 2012 - 10:35 AM

The sunrise on this Friday the 13th was at 6:35am, and our WJLA roof cam captured the beautiful scene as mid level clouds passed through the crisp April air.  Daylight increases every passing day this time of year, and today we can enjoy 12 hour 10 minutes of daylight. 

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UCACN Responds To Cliff Mass' Blog On U.S. Forecast Accuracy

April 13, 2012 - 05:00 AM

This guest blog is a response by the UCAR Community Advisory Committee to NCEP  to a recent blog by Dr. Cliff Mass on the state of numerical weather forecasting in the U.S.  There are important discussions going on within the meteorological community (both science and budgets) which impact the basic "superstructure" of  "NWP" the core of weather forecasting. I think this response is well worth reading- Bob Ryan.  The views expressed do not necessarily reflect those of ABC7 or NC8.

As noted in Prof. Cliff Mass’s blog postings on 18 March and 7 April 2012, the performance measures for global model-based guidance for U.S. weather forecasts show the National Centers for Environmental Prediction (NCEP) lagging behind the European Centre for Medium-range Weather Forecasts (ECMWF) and the Meteorological Office of the United Kingdom (UKMO). The blog provided a number of sharp criticisms of NCEP, the National Weather Service (NWS) and the National Oceanic and Atmospheric Administration (NOAA), and it noted that, “a blue ribbon panel did a review of NCEP in 2009 and came to similar conclusions.” We, the members of the UCAR Community Advisory Committee for NCEP (UCACN), have followed up on that review and we find, in contrast to the statements in the blog, that NCEP is a significantly different place than it was even a few years ago with considerable promise for the future. We are writing to comment on some of Dr. Mass’s main points.

An independent review committee was commissioned by NCEP in 2009, managed through the University Corporation for Atmospheric Research (UCAR), and charged with critically reviewing the nine Centers that compose NCEP as well as the office of the Director of NCEP. This blog provided a link to one of the ten reports (EMC; information about the review and the other 9 reports can be found here: The UCAR review committee found many gaps and weaknesses (as well as strengths) in various parts of the NCEP enterprise, as suggested in the blog, and it made over 260 specific recommendations to help NCEP improve its products and services. One of the major recommendations was to form an external advisory committee to receive more frequent and expert advice from stakeholders in the academic and business communities. NCEP has embraced that recommendation and sought help from UCAR, which formed the UCAR Community Advisory Committee for NCEP (UCACN). Fred Carr (University of Oklahoma) and Jim Kinter (Center for Ocean-Land-Atmosphere Studies – COLA and George Mason University - GMU) were asked to serve as founding co-chairs of UCACN.
The UCACN has met once (in October 2011) since being formed, and the report of that meeting is also on the above web site. Based on the 2009 NCEP Review and the findings of the UCACN committee, we have the following comments on the 5 major points raised in the March 18 blog entry, repeated for convenience here:

1. The U.S. has inadequate computer power available for numerical weather prediction.
This is more correctly stated as NCEP has far less computer power available for its short and medium-range (0-16 days) forecast products (single plus ensemble runs) than does the ECMWF (and other centers). As rightly noted in Part II of Prof. Mass’s blog, two reasons for this are that (1) the NCEP supercomputer has less power than its competitors, and (2) NCEP's mission is an order of magnitude broader than ECMWF's, encompassing the prediction of not only medium-range weather but also seasonal and annual climate, marine and aviation weather, ocean waves, currents and storm surges, space weather, severe storms, hurricanes, air quality, etc. with mandates for ecosystem and decadal forecasting in the future. NCEP is under-resourced for this broad mission, a finding that motivated the 2009 NCEP Review to recommend that the mission be adjusted to fit the resources or that more resources be found. However, it is impossible for NCEP to discontinue services mandated by higher authorities, and it is extremely difficult to increase resources when NWS and NOAA budgets are being cut. The blog is correct in pointing out that there is excellent justification for substantially higher computer capability for operational prediction; in fact, an increase by a factor of at least 10 was recommended in the 2009 NCEP Review.
To update the information provided in Part II of the blog on the topic of computer procurement, NOAA recently (Feb 2012) awarded a $500 million, 10-year contract for the next generation operational high performance computing (HPC) system to IBM. An IBM iDataPlex system, which is a 149 teraflops (TF) system with 7,168 cores, based on the Intel Sandy Bridge chip, is expected to be operational by the end of 2013. A larger and more capable system was originally proposed by NCEP/NWS and NOAA, but budget constraints at a higher level restricted the size and speed of the system purchased. While the new system is rated lower than the 150-TF system at the UKMO and the 182-TF system at ECMWF and will be considerably smaller than machines available to academic researchers in the U.S., it is a step up in capability and capacity for operational weather prediction.

Supercomputer Data Center

It should be noted that HPC requirements are not limited to the supercomputer, but also include concomitant storage capacity, network bandwidth, information technology security, and reliability. The numerical guidance for forecasts has a 99.99% reliability requirement that demands a fully-redundant backup facility, removed from the main facility, with sub-second failover capability. As a result, Prof. Mass’s estimate of the cost of a 100,000-core system at $25 million neglects the total cost of operational, time-sensitive environmental prediction faced by NCEP. It is also noted, in response to the blog’s “not forward-leaning” comment, that NCEP’s current HPC system is the same (though with less capacity) as the ECMWF one, and the 2013 system will be the same (likewise with much less capacity) as that recently purchased by the National Center for Atmospheric Research (NCAR); all these systems are bid competitively, so any vendor can participate. 

2. The U.S. has used inferior data assimilation.
This statement is correct, and the ECMWF analysis is better. However, as an example that partially refutes reason #3 below, NCEP is partnering with NASA, a NOAA research lab and the Univ. of Oklahoma to develop ensemble-based hybrid (meaning combined with 3D- and 4DVAR) assimilation systems that should help them improve forecast skill. The new system being tested now significantly improves the Global Forecast System (GFS) results and will be implemented in May 2012.

3. The NWS numerical weather prediction effort has been isolated and has not taken advantage of the research community.
This is a frequent criticism that is only partially true. Many of NCEP’s modeling systems have come from other institutions, and over 70% of the modeling codes currently running in the NCEP Production Suite originated outside of NCEP. For example, EMC is partnering with the Developmental Testbed Center (DTC) at NCAR to facilitate transition of advances in mesoscale modeling into operation. Also, EMC and NCEP leadership have recently initiated many collaborative activities both in the US and abroad. In particular, NCEP has joined with the Canadian Meteorological Center (CMC) to create the North American Ensemble Forecast System, and the NCEP Climate Forecast System is included in the EuroSIP multi-model ensemble to improve seasonal predictions.

NAEFS Model - North American Ensemble Forecast System

This is evidence that NCEP is heeding the research community’s finding that multi-model ensembles are advantageous for both weather and climate prediction.
However, the ability to have an effective Visiting Scientist Program at NCEP has indeed been limited by lack of space and funds. The late summer 2012 move to the new NOAA Center for Weather and Climate Prediction (NCWCP), located in a research park in College Park, MD, will significantly improve opportunities for NCEP to interact with the external research community. Within the facility there are 40 spaces identified for visiting researchers, and the UCACN and NCEP are currently working with partners to obtain adequate resources to support visiting scientists.

4. The NWS approach to weather related research has been ineffective and divided.
As the blog later indicated, this statement is more correct if the word NOAA is substituted for NWS. The research components of NOAA and the operational weather and climate prediction component (NWS/NCEP) are bureaucratically separated and it requires orders from the NOAA Administrator to overcome barriers between them. The 2011 UCACN Annual Report recommended that interactions between NOAA research labs and NCEP need to be much more effective. Also, while NOAA has a limited external grants program for climate, it allocates even less funding for weather and NWP research, thus limiting academic scientists from receiving funding to support research that might directly benefit NCEP. In spite of all these barriers, NCEP has initiated and benefitted from collaborations with sister agencies, and is trying hard to start additional partnerships. The programs that NOAA funds to support weather and climate research should be expanded and better focused on numerical modeling to address this need more directly.

5. Lack of leadership.
This particular criticism is certainly not true about NCEP leadership. The UCACN can unequivocally state that NCEP leaders are a highly dedicated group who are not satisfied with the status quo, and who are working as best they can with the resources they have to improve the situation. We note that NCEP leadership is tracking all 263 of the 2009 Review recommendations to their completion, and many improvements have already been made. We know that the NWS Director had to make many painful budget cuts this year, but the NWS protected an important $10M increment for the new computer procurement, and did not cut NCEP’s funding. The UCACN has briefed NOAA officials about how to improve US NWP, but NOAA is dealing with its own budget cuts.
NCEP is doing its best within limited resources and disadvantageous federal personnel policies. Clearly the priorities for NCEP are not being set appropriately by NOAA, the Department of Commence or Congress. Many in Congress will not support funding increases for any cause, no matter how economically beneficial. Since NOAA/NWS/NCEP employees are forbidden from lobbying on their agency’s behalf, it is up to private citizens and the industries that rely on weather and seasonal forecasts to advance the cause for improved NWP.
As an aside, we note that NCEP has to resource and manage more than just computers and models. It also directs seven forecast centers, such as the National Hurricane Center, the Storm Prediction Center, etc., most of which are the best in the world in their respective missions. It is not sufficient to consider a single score of model forecast performance as indicative of the quality of the entire organization.
There are many challenges facing the U.S. weather prediction effort, and while there remain systemic impediments to making progress, the UCACN finds that NCEP is much more receptive to working with the external community. We expect significant improvement and accomplishment in the years to come.

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