From the ABC 7 Weather team

Archive for February 2013

Fun at school: Our newest WeatherBug school

February 28, 2013 - 03:37 AM

We now have over 400 schools in the Washington area that are part of the WeatherBug network. 


Schools with interactive weather stations and cameras. I started this network (in a previous life) as the "4-WINDS" program of weather stations in schools and using weather and weather stations in schools as a "window into science and math".  Wednesday I had fun at one of our news schools to join the network, St. Thomas Aquinas Regional School in Woodbridge.


I not only talked about how I became a meteorologist, but took lots of great questions.


Then a tour of the school that had a "weather theme" competition in the  school hallways.  Everything from sunshine, to wind, storms and a great tornado.


.... and a winter theme with a familiar mug dressed for winter.


and a pre-K group of penguins.  


Everyone was into weather and as you drive around your neightborhood, if you see something like this on the roof. 


It's one of our WeatherBug schools and may be the home of a future meteorologist.  Find out more about the program and how your school can join here.

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March weather averages, extremes and milestones for the D.C. area

February 27, 2013 - 01:44 PM

March is only two days away and meteorological winter is almost over, but that doesn't necessarily mean warmer temperatures are on the horizon for the near-future. Taking a look at the climate data for Reagan National (and Washington D.C. for earlier climo data) spanning back to 1872, I've highlighted some of the averages and extremes that might interest you.

Heading into March, the average high temperature is already 51 degrees, which is 8 degrees warmer than the lowest average high in January. By the end of the month, the average high is up to 61 degrees. There is typically a wide range of temperatures throughout the month, however, with records ranging from the coldest record low (4 degrees on the 4th in 1873) to the warmest record high (93 degrees on the 23rd in 1907). That's an 89 degree spread, which ranks as the 3rd most changeable month behind February (99 degree spread) and January (93 degree spread).

2012 was the warmest March on record

Last year was actually the warmest March on record for many states from the Mid Atlantic through the Midwest. This includes the warmest on record for D.C., with a +10 degree temperature departure for the month. One record high was recorded just last year on the 15th, when the temperature soared to 82 degrees. I wouldn't worry too much about reaching a record low, as the last one was recorded on the 15th in 1993, when the temperature fell to 15 degrees.

Precipitation is usually on the rise for the month of March, with an average of 0.09" on the 1st of the month, but up to 0.12" by the end. The month averages 3.48" on a whole. Snow still isn't out of the question either. In 2009, Reagan recorded 4.5 inches of snow on the 2nd, though that wasn't representative of other areas which had more than 11 inches in Southern Maryland as shown below. In 1999, 8.4 inches fell on the 9th. The big one for D.C. was in 1942 when the region was struck with 11.5 inches. And that happened on the 29th! I guess there is still hope for the snow lovers after all.

March 2, 2009 Snow (Courtesy: NWS Sterling)

Snow isn't the only weather feature through the month, as severe weather is also possible. Just two years ago, two tornadoes struck the region in Bealeton, VA and Chantilly, VA, so the threat for storms is on the rise as well.

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Full "Snow Moon" in the Nation's Capital

February 25, 2013 - 11:03 PM

Tonight's full moon is commonly referred to as the "snow moon" even though it's hardly been "snowy" this February in Washington.  I'm sure folks in the mid part of the country aren't saying the same.  Once again, another powerful winter storm is slamming the central U.S. 

Check out a great close up image of the full moon in our Daily Eye Wonder:

Naval Observatory

We captured a beautiful timelapse of the moon rising over the Nation's Capital.  Watch closely and see the moon's reflection rise on the Potomac.  What a brilliant, and bright, city we live in. 

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Snow storm hits Texas and Midwest, but it's rain again in D.C.

February 25, 2013 - 03:06 PM

A powerful storm brought blizzard conditions to Amarillo, Texas, but that storm will reform and bring rain to Washington Tuesday.

With the possibility of heavy rain for a time later Tuesday, the metro area is under a flood watch Tuesday afternoon through Tuesday evening.


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Heavy rain possible in the D.C. area tomorrow; Brief mix possible

February 25, 2013 - 11:21 AM

A strong winter storm is affecting the Central Plains once again with heavy snow and blizzard conditions stretching from northern Texas through western Oklahoma and southern Kansas. Up to a foot or more of snow is expected in those areas, along with wind gusts over 50 mph at times.

As I write this now, Amarillo, Texas is seeing blowing snow with sustained winds at 40 mph, gusts to 52 mph, with a foot of snow already on the ground. See the video here.

As this strong storm moves into the Midwest, another area of low pressure is expected to develop over the Carolinas Tuesday morning. This new area of low pressure will bring moderate to heavy rainfall to the D.C. area through the afternoon and evening hours.

With chilly morning temperatures and weak high pressure located to the north of D.C., a light wintry mix may be experienced at the onset of precipitation closer to noon, but it will be very short-lived.

4km NAM model forecast for Noon

Areas west of the Blue Ridge may experience a longer duration of a wintry mix of snow, sleet and freezing rain, but it should all change to rain by the afternoon. I even circled the area in the model above that shows temperatures at or below 32 degrees at noon.

This should be limited to the Shenandoah Valley and the sheltered valleys in the mountains west of Interstate 81. A Winter Storm Watch is in effect over the mountains of West Virginia for the threat of freezing rain, but no watches or advisories are posted for our viewing area.

HPC Precipitation Forecast for Tuesday

Heavy rainfall will be possible with this system as well, with up to an inch of rain possible through tomorrow night. The HPC graphic above for the precipitation forecast shows the potential for 0.75" to 1" of precipitation for the D.C. area.

This would be great as Reagan National is down 1.5 inches of precipitation since Jan. 1, while Dulles and BWI Marshall are down around a half an inch.

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D.C. Winter of 2013: Dry and Warm

February 24, 2013 - 06:52 PM

As the last few calendar days of February get flipped over, it also signifies the end of Meteorological Winter. Simply put, the three coldest months of the year define Meteorological Winter. So, meteorologists crunch the numbers for snowfall and temperatures from December 1-February 28 (or 29 if a leap year) to put in the books at the end of the season. How did this winter rank for Washington?

The all-important factor is snowfall. Didn’t see much this year, did we? Nope and it sure was a dry winter! Here are the numbers from each of the big airports in the region, plus Hagerstown.


The Washington-Baltimore metro areas didn’t see the snowy side of winter last year either.


Even though above average again this year, temperatures were TWICE as warm last year. Check out the numbers below from the official reporting station in Washington, Reagan National Airport.


The winter of 2011-2012 was the last time the winter was cooler than average. Please note the FINAL calculation will be done after the month ends and the Weather Service crunches the numbers.

As we close out the winter season, there’s a better chance of rain than snow by Tuesday followed by more seasonal temperatures and a few spits of rain, sleet or snow to close out the month. More than likely the temperatures through Thursday, February 28 will not have much of an impact on the outcome of the overall average winter temperature for the Washington area.

Cheers to spring!

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Northern Lights on the Kennedy Center

February 22, 2013 - 10:00 PM

Have you ever wanted to see the Northern Lights?  Well, if you live in D.C., there's a chance you'll get to see them over the next few weeks.  OK, it's not the real aurora borealis in the sky, but you can get a glimpse of the lights on the Kennedy Center!

WeatherBug camera

That's right.  The Kennedy Center will feature the "Nordic Cool" festival through March 17th.  Every night between 5:30pm and 11:00pm the four sides of the Kennedy Center will display the Northern Lights.

Denmark's most innovative lighting designer, Jesper Kongshaug, will bring the effects of the aurora borealis to Washington D.C. on the white marble walls of the Kennedy Center.  The "Nordic Cool" festival also showcases Northern European culture featuring music, theater and dance, as well as exhibitions, literature, film, and cuisine.

Here's a neat timelapse.


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Latest on today's sleet and snow in the D.C. area

February 22, 2013 - 12:12 PM

Areas of light snow, sleet and freezing rain have moved through parts of the D.C. area and will continue to do so through the afternoon hours. It appears the timing was spot on with a late morning to lunchtime arrival and precipitation amounts look light just as forecasted.

Winter Weather Advisory until 10am Saturday

The National Weather Service has extended the Winter Weather Advisory to other counties such as Loudoun in Virginia and Frederick in Maryland and points west.

The thought is that precipitation will continue through the afternoon with pockets of sleet and freezing rain before a lull in the precipitation for the evening commute. The NWS decided to keep the advisory through 10 a.m. tomorrow as light freezing rain and drizzle may be possible tonight, and a few slick spots will be possible on untreated roadways in those counties.

Closer to the D.C. metro area and points south and east, any frozen precipitation should change over to plain rain overnight. This rain will be very light through the overnight hours, but will pick up in intensity tomorrow as an area of low pressure skirts by along the coast.

The heaviest rainfall totals will be over the Eastern Shore, but even the D.C. metro could see up to 0.3 or 0.4 inches by the time the rain ends Saturday evening. Below is a look at the 4km NAM model forecast for late Saturday morning.

4km NAM Model Forecast for 11am Saturday

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Light wintry mix likely on Friday in the D.C. area

February 21, 2013 - 05:30 PM

A powerful winter storm has been wreaking havoc on much of the central United States, but as it moves east it will weaken. High pressure gave us a sunny and beautiful (though cold) day in the D.C. area ahead of this system. As the storm progresses to the east coast, clouds will enter the region overnight, and precipitation will enter the western suburbs by later tomorrow morning.

What you should expect:

At this time, our team thinks that precipitation will start in the form of some light snow around lunchtime tomorrow in the D.C. metro and a little earlier in areas to the west. This snow will quickly change over to light sleet and possibly even some light freezing rain and continue through the afternoon and evening. Below is a look at a model forecast for tomorrow around Noon. This may be a little overdone as far as precipitation but the type looks spot on with some snow, sleet and freezing rain in the area.

4km NAM Model for Noon Friday (WeatherBELL Models)

Even though this will be an event with a long duration, precipitation totals do not look very impressive. Current model guidance only depicts around a tenth of an inch of liquid equivalent for the D.C. area. With temperatures hoving around or just above freezing, the roadways should mainly just be wet. An isolated slick spot may still not be out of the question for the afternoon and evening commute.

As of now, there are no advisories posted for our area but they are currently up over West Virginia and southwestern Virginia along the I-81 cooridor. Precipitation should change to rain Friday night into Saturday morning, and more rain will be possible through the day on Saturday as a new low forms and moves off the east coast. The heaviest rainfall totals from this new low should be over the Eastern Shore.

ECMWF Forecast for early Saturday Afternoon (WeatherBELL Models)

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Wintry Mix Possible Friday. Slippery PM Commute?

February 20, 2013 - 08:14 PM

A powerful winter storm is taking shape in the Central U.S. and will impact us, in D.C., by weeks end.  The storm system is originating in the Desert Southwest and has already brought snow to parts of Arizona, including Tucson and Phoenix.  Much of the Plains and Midwest already under either winter storm warnings (pink), winter weather advisories (purple), or winter weather watches (blue). 

The center of the storm system will track North through the Plains and into the upper Midwest through Friday.  Notice, in the image below, the area of low pressure over Chicago.  Also, notice the warm front (red) through the Carolina's and the pink (ice) that extends North of that front.

As the warm front lifts North through the day, Friday, light precipitation will accompany the front, especially out ahead of the front.  I want to emphasize "light" since some of the latest trends are showing much less moisture associated with the warm front, which would be a good thing, especially since the precipitation could fall as the dreaded "wintry mix". 

Check out forecast temperatures at 4pm Friday.  I grabbed a wide shot to show the cold air over the MidAtlantic, but to also show the milder temperatures in Kentucky and Ohio.  Those will be areas south of the warm front by Friday afternoon.  Temperatures at 4pm around the metro area will be in the mid to upper 30s.

Penn State e-wall Hi-Res NAM 18z

Temperatures will be around freezing, but mainly above the freezing mark, so that would rule out freezing rain in D.C. with any precipitation around that time.  Temperatures aloft, or higher in the atmosphere, will be around or above freezing, so that's why there's the concern for freezing rain and/or sleet.  Here's a great link to help explain the process of snow, sleet, and freezing rain

As mentioned before, the amount of moisture associated with the warm front continues to be less and less with the newest guidance, but certainly something we'll want to monitor.  If the precipitation would fall around the evening commute, which it looks like the likely timing, as of now, then that could certainly cause some travel problems.  Temperatures through Friday night and very early Saturday morning will be close to freezing, so the ice concern will stick around through the period, especially with more moisture moving in overnight Friday.

By Saturday mid morning, temperatures will be above freezing throughout the atmospheric profile, so a chilly rain in store for Saturday.  Another area of low pressure will develop over the Southeast and become more organized, as it moves up the coast. 

18z GFS
A rainy Saturday for D.C., but maybe more snow for New England come Sunday, as the same low intensifies off the New England coast. 

As always, we'll watch the developing systems and keep you updated with any new information!

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Warmer but More Snow?: Does this make sense?

February 20, 2013 - 04:17 PM

A recent story by the Associated Press's Seith Borenstein about global warming causing more blizzards sure stirred up the blogosphere. But even if the trend here in D.C. is for decreasing winter snows as shown in this Capital Weather Gang story,  some areas are likely to see increasing winter snows in a warming climate.  Here's where and why.  Look at this satellite view of New York from two days ago. 


Lake Ontario is almost completely ice free.  The water temperture is 35°.  Here is how New York State looks today. 


The Lake Effect snow machine is really going with the cold arctic air sweeping across the lake and generating heavy snow in the Tug Hill area east of Lake Ontario.


The Lake Effect snows essentially stop when the Great Lakes freeze.  No moisture from frozen lakes to power the local snows.  But studies have shown that in a warmer climate, the Great Lakes, as now Lake Ontario, are less likely to freeze and areas downwind of the lakes are likely to receive increasing snows in the years ahead.  Snow lovers, you know where to move for more snow in the coming years.  Syracuse and Oswego.:>)


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D.C. pollen levels well above average so far this year

February 20, 2013 - 12:57 PM

The meteorologists in our department usually receive a daily "Pollen and Spore Report" from Susan Kosisky. Susan is the Chief Microbiologist at the US Army Centralized Allergan Extract Lab located in Silver Spring. She is also the Director of Aerobiological Reporting and Evaluation at the US Army Garrison-Forest Glen. Basically, she knows what she's talking about when it comes to pollen in the D.C. area.

Just last week, the tree pollen levels in the D.C. area were in the moderate range, which I thought was a little on the early side. I decided to ask her a couple questions about the season so far and what that might mean for the spring ahead of us.

I asked her about the warm weather we've had (at least in January, as well as a few spikes in February) and how that has attributed to the pollen levels.

Kosisky replied, "Indeed, like last year with the warmer winter weather, it looks like we are seeing some higher levels for our early pollinating trees (maple, elm, alder, cedar/cyp/juniper, birch) family pollen members. I have attached a graph which shows cumulative pollen totals for January 1998-2013. 2012 and 2013 levels for January are quite a bit above the average. The average January cumulative tree pollen total is around 16.6 grains/cubic meter for the month. In 2012, we were at 57.2 grains/cubic meter and in 2013 we had 58.8 grains/cubic meter."

Here's the graph below.

January Tree Pollen Levels 1998-2013

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Beautiful sunrise prior to the wintry mix this morning (Video)

February 19, 2013 - 12:10 PM

There was plenty of sunlight for a gorgeous timelapse this morning, leading to many nice pictures coming in to our station as well as a fantastic timelapse taken from our roof camera. Here is the movie that we put on Youtube in our ABC7Weather account.

Those nice colors were caught in a few photos as well. This one was sent in to us by A B Pan Photography, who often shares beautiful pictures from around the D.C. area.

Photo taken by A B Pan Photography

Here is another shot below from this morning in Leesburg, VA taken by Glynnis Morgan Dwelly. The colors were amazing.

Taken by Glynnis Morgan Dwelly

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Top of the World: Installing a weather station in the Himalayas

February 18, 2013 - 03:41 AM

The picture with this story might have gotten your interest.

The story below is about Michael Siemann, who is finishing his graduate work at the University of Maryland and also working with our partner WeatherBug. Michael recently traveled to Nepal to install one of the highest weather stations in the world.

Michael describes his trek here and also worked with  Dr. Mahabir Pun and his  organizations, Nepal Wireless  and, which are doing a lot of great things for the country of Nepal

They can always use more help. Read more about Michael's great trek and the weather observations to come from Nepal here.

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Meteor or Meteorite: What happened in Russia?

February 15, 2013 - 04:48 PM

A large meteor exploded in the morning sky over Russia.  It's been called a "meteorite" but so far nothing has been found on the ground.  The huge fireball and explosion was a "meteor" or large space rock crashing into the earth's atmosphere and traveling at a speed as high as 40 miles per second.  A large space rock such as this may enter the atmosphere once or twice a year, but since 3/4 of the Earth is water, most are not observed and certainly not felt in urban areas such as today's spectacular and damaging event in Russia. Here's a dramatic compilation of what was seen, as shown on Russian TV today. 

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Light snow possible tonight and this weekend in the D.C. area

February 15, 2013 - 04:20 PM

A potent cold front is moving into the region this evening with rain developing during the evening commute and a few snow showers are possible later tonight. After temperatures reached the 60 degree mark through much of the D.C. area, accumulations appear like they will be limited to grassy surfaces tonight. 

This cold front will push through the area tonight bringing with it much colder temperatures in the 30s by Saturday morning. Anything that falls may leave behind some wet roadways, and a few slick spots may be possible Saturday morning, a lot like Thursday morning. This will especially be the case on elevated surfaces such as bridges and overpasses, so be sure to take added precautions while out driving early tomorrow.

7AM Forecast Temperatures Saturday

Saturday will feature much colder temperatures with highs in the 30s and the chance for more scattered flurries and snow showers. An area of low pressure is expected to develop off the east coast Saturday and Saturday night which will bring that chance for snow. There is the potential for a dusting or possibly an inch east of D.C. mainly over the Eastern Shore, but there is the outside chance for an inch or so around Southern Maryland as well as that low moves up the east coast.  By Sunday, an additional round of light snow showers or flurries will be possible, but little to no additional accumulation is expected.

As the coastal low intensifies offshore, it will kick up the winds both Saturday and Sunday.  So, not only will it be much colder this weekend, but it will be blustery!  Northwest winds will gust between 25 and 35 mph, especially by Sunday, so it will feel like the teens and 20s this weekend.

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Rainwater, Sediment and the Bay: Visual example of runoff

February 15, 2013 - 03:31 AM

The last week several quick moving storms have dumped 1-3" of rain, and a bit of snow in the region we live in and that surrounds our beautiful Chesapeake Bay.  Here is a map from NOAA/NWS of the general rainfall this past week. 


 Some of the heavier rain (and some snow) fell  to the north and east of the D.C. area but also over the Susquehanna River drainage basin. For a time after one of the storms with moderate rain, more than 30 MILLION GALLONS of water was flowing down the Susquehanna.  Not only water but with generally bare soil in winter, also tons of soil.  The Susquehanna is the largest tributary to the Chesapeake Bay which is the largest estuary in the United States.  Here is a dramatic image Thursday from NASA's Aqua satellite (great images here)  


You can see the sediment (see the brown color in the Bay?)  from that rain and runoff flowing into the northern  Bay, and flowing down the Potomac River.  Is this all due to human impacts?  Of course not, but it is an example of how we do have to be aware of land use and "best practices" to assure that "our Bay" stays as healthy as possible.


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Asteroid Friday: NASA Live Stream found here

February 14, 2013 - 02:00 PM

An asteroid half the size of a football field, around 150 feet wide, will pass the earth tomorrow early afternoon. This is record-setting as it is the largest object that NASA has ever seen pass this close by to earth. The asteroid, named 2012 DA14 will be closest to the earth around 2:25pm EST tomorrow afternoon. When it passes by, it will be closer than weather satellites and GPS satellites in orbit. You can find NASA's live stream below which will be a half hour commentary from the Jet Propulsion Laboratory in Pasadena, CA starting at 2pm EST.


Depiction of Asteroid 2012 DA14's path

Near real-time imagery of the flyby from astronomers in Australia and Europe will be made available at Noon EST tomorrow and can be found below.


There will be a Ustream available starting at 9pm EST tomorrow which will run for 3 hours showing the feed from a telescope at the NASA Marshall Space Flight Center in Huntsville, AL.


To watch for other asteroids, be sure to check NASA's Asteroid Watch page and another good resource is the near-earth object program which is run from the JPL.

I wanted to give a big thank you to our colleague Joe Witte for forwarding along this information to us.

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Greenland Ice: More melting and an immense iceberg

February 14, 2013 - 10:02 AM

"Chasing Ice" is a incredible documentary film that has won numerous awards, but was not nominated for this year's academy award for documentary film. But it was nominated for best original song. 

The film documents some of the rapid changes taking place in the world of ice: the "Cryosphere". Some recent studies have shown increasing evidence of increasing melt rates of the immense ice pack covering Greenland. This past summer showed the longest duration of Greenland surface ice melt since satellite measurements began in 1978.


The long term trend from this same report also shows increasing areas and duration of melting Greenland ice in the summer. 

The impacts of  some of these changes are dramatically captured in "Chasing Ice" and this video showing the breaking up of glacier ice that "calved" an iceberg about the size of Manhattan. 
Enjoy the video and better yet watch the movie. . . and we'll all find out if the song wins an Oscar too.

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Daylight Saving Time 2013 is right around the corner

February 14, 2013 - 04:00 AM

Thursday's sunrise took place 7 a.m. and the sun will set at 5:45 p.m., giving the region 10 hours and 42 minutes of daylight. This is an hour more daylight than observed since the Winter Solstice (9 hours, 26 minutes). As far as Doug Hill and I am concerned, this is a great thing.

Did you know by the end of the month of February, the D.C. area will gain 36 minutes of daylight? The sunrise will go back to 6:42 a.m. and the sun will finally set at 6 p.m.

Daylight Saving Time begins on March 10,and everyone will apring forward an hour, with the sunrise once again after 7 p.m. but the sunset also continuing through 7 p.m.

This is great for those that leave work in the evening hours, but I'll tell you, our morning meteorologists aren't big fans of this as they typically go to bed around 6 p.m.!

It's amazing that another 53 minutes of daylight is gained between March 10 and March 31, and in another month through the end of April, another 1 hour and 12 minutes is gained. This comes to a whopping 3 hours and 7 minutes of daylight gained by April 30, when there will be 13 hours and 49 minutes of daylight for D.C.

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