From the ABC 7 Weather team

Archive for May 2012

Washington, DC weather forecast and rain video

May 15, 2012 - 12:33 PM

It was a very soggy start to our Tuesday, but the sun eventually appeared and we caught it all on our rooftop camera.  Here's another great timelapse of the sky over Washington, D.C. from this morning:

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Washington DC rainfall totals

May 15, 2012 - 09:18 AM

Washington D.C. remains in a  precipitation deficit of more than four inches since January 1st, but we put a nice dent in that deficit with the recent rain.  I'm a happy gardener today!  Here's a breakdown of the highest rainfall totals per county from Monday morning through 9 a.m. Tuesday:

 Washington, D.C.:
• Children’s Hospital: 1.24”
• Lafayette ES: 1.07”

Arlington, VA:
• Washington-Lee HS: 0.90”
• Campbell ES: 0.88”

Fairfax County, VA:
• Centreville: 1.48”
• Oakton: 1.27”
• Fairfax: 1.18”
• Burke: 1.16”

Loudoun County, VA:
• Aldie: 1.30”
• Chantilly: 1.18”
• Leesburg: 0.98”
• Ashburn: 0.97”

Prince William County, VA:
• Dale City: 1.52”
• Manassas: 1.40”
• Woodbridge: 0.95”
• Quantico: 0.87”

Montgomery County, MD:
• Olney: 1.82”
• Gaithersburg: 1.54”
• Germantown: 1.43”
• Rockville: 1.39”

Prince Georges County, MD:
• Adelphi: 1.41”
• District Heights: 1.27”
• Suitland: 1.15”
• Oxon Hill: 1.05”

Charles County, MD:
• Indian Head: 1.16”
• Waldorf (Westlake HS): 0.83”
• Waldorf (Wade ES): 0.56”

Frederick County, MD:
• Myersville: 1.34”
• Monrovia: 1.20”
• Frederick: 1.11”
• New Market: 1.09”


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Weather Text Alerts: A New Service

May 14, 2012 - 10:40 PM

Ring, Ring -- this was the main use of telephones and cell phones in the beginning, but in today's day in age it's all about mobile apps, GPS, gaming, email, text messaging, video chats, and much, much more!  To be honest, I can hardly keep up with it. 


Now I will say, I do like to keep up with the latest weather apps, since I always like to know what's going on with the weather.  Obviously I'm bias, but I think the StormWatch 7 app for iPhone and Andorid is a great go-to (sorry, had to plug!).  Whether you download weather apps or not, you'll soon start receiving text alerts when severe weather warnings are issued.  

Wireless Emergency Alerts (WEA) are emergency messages sent by authorized government alerting authorities through your mobile carrier.  WEA is a partnership between FEMA, the Federal Communications Commission (FCC), and wireless carriers, to enhance public safety.

Anytime a life threatening weather warning is issued you'll receive a text message.  The National Weather Service will send out alerts such as, tsunami warnings, tornado and flash flood warnings, hurricane, blizzard and a few warnings.  This alert system will also be utilized to send Presidential alerts and Amber alerts.

Now, don't worry - your phone won't start alerting you when there is a tornado warning in Oklahoma, but it will text you if you are in the geographic area with an active warning.   How does your phone know?  An alert will be sent through the nearest cellular broadcast towers, so it is not utilizing GPS and therefore does not know your exact location.  Any WEA-capable phone in that particular area on a participating network will receive the alert.  The text alerts won't cost you anything either. 

The goals is to have these push text messages sent within the next few months.  Some areas have already undergone test text alerts.  You can find out more information here.  

With such highly sophisticated "smart" phones, I think this is a "smart" and effective way of reaching the public and alerting them to pertinent information.  It could help save your life. 

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Washington DC rainfall totals forecast

May 14, 2012 - 08:07 AM

The D.C area is abnormally dry, and part of the region is facing a drought with a precipitation deficit of more than five inches since January 1st (DCA: 5.21" below normal since 1/1/12).  We need rain, and we're getting it, but will it put a dent in the deficit?  Here's a video indicating the latest prediction from our own computer model (06Z Microcast). 

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Washington DC hourly weekend forecast for Mother's Day

May 11, 2012 - 08:14 AM

Overall, the weekend looks great especially on Saturday. Expect total sunshine and highs near 80° on Saturday with low humidity.  Some upper-level energy should develop clouds on Mother's Day, but temperature are still expected to spike near 80° in the afternoon.  It's worth noting that an few sprinkles are possible over the higher terrain of West Virginia and Western Maryland by Sunday evening, and there's a slight chance a few drops could fall over the Shenandoah Valley late Sunday evening.  Happy Mother's Day to all the moms! 






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D.C. Drought

May 11, 2012 - 06:00 AM

Finally enought pitter patter to amount to something!!  The rain earlier this week certainly put a dent in our rainfall deficit, but we're still far below the yearly rainfall average.  Take a look at the radar at 7PM on Wednesday, May 9th. 

Super Dopple 7 at 7PM, Wednesday, May 9th

This is exactly what we needed -- a large, uniform, swath of moisture for a few hours.  Right here in D.C. we received a little over a half inch.  Folks on the Eastern Shore got some of the heaviest rain with rainfall totals over two inches in some spots!  The rain is certainly much needed, as many areas across the region remain under a moderate to severe drought.  Here's the most recent drought index.

Drought Monitor

Now, you might be wondering why the Eastern shore is still under a severe drought with over two inches of rain Wednesday.  The drought index is issued every Thursday morning, but the data is only recorded through Tuesday.  Since the bulk of the rain fell on Tuesday and Wednesday, this map doesn't show how the drought is affected by that rain.  We'll have a better idea next Thursday on how the impact of this weeks rain on the drought. 

Here's a list of some rainfall totals across our region from our WeatherBug locations.

WeatherBug rainfall totals from Tuesday and Wednesday

You're seeing that right with over two and a half inches of rain in Ocean City, MD.  On the other side of the Bay, rainfall totals weren't quite as impressive, comparatively, with about a quarter to a half inch on average.  As mentioned, it's wonderful to receive the rain, no how much we get when it's particulary dry.  We do still need a few more good soakings to catch up to the yearly averages. 

Yearly Rainfall & Departures

Before the rain on Tuesday, D.C. only had 3.23" (as of May 6th) of rain since March 1st.  There have only been 5 other years we've had less than 3.25" of rain from March 1st through May 6th.  That gives you an idea of how dry this spring has been, so far. 

No significant rain is in the forecast through the weekend, but late Sunday through early next week we could see the chance for a few showers.  The rain dances continue. 

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The Top 15 Weather Related Movies

May 10, 2012 - 05:40 PM

Here's my list with the help of some of my co-workers on our favorite weather related movies. Be sure to let us know if we missed your favorite movie or if you think the list should be re-ordered on our facebook page! There are definitely a few I have left out so be sure to let us know. I hope you enjoy this list. It will at least occupy some time if you get bored at work!

15. White Squall (1996)

I can't remember what this movie was about at all besides a boat and the fact that lightning was striking everywhere around it, but I remeber it being awesome.

14. Water World (1995)

Good bye Ocean City, Bethany and Rehoboth. This is what's going to happen once the polar ice caps melt for good. For now though, all I have to say is, "Dry land is not a myth. I've seen it!"

 13. Fargo (1996)

I didn't actually see this movie until last year, but I remember hearing it from the other room as my dad watched it when I was younger. Talk about violent! Not for the kids, but man does Fargo look brutal in the winter. I think Adam Caskey would just have to say uufda to that!

Because of the violence, I'm not even going to embed a video of it in the blog, but you can see one or many here if you like. Turns out it was Siskel and Ebert's favorite movie of 1996.

12. Alive (1993)

This was about the Uruguayan Rugby Team that crashed in the Andes Mountains. Fantastic movie if you haven't seen it. Don't watch this if you're flying over the mountains anytime soon.

11. The Shining (1980)

This of course deals with weather because they can't leave. All snowed in... It also just happens to be one of the greatest horror flicks of all-time.

10. To Die For (1995)

Mr. Steve Rudin wanted me to add this one. You have to throw this in there for the mere fact that she is a meteorologist! I never saw it personally but as I was 13 when it came out I am pretty sure my mother wouldn't have let me see it.

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Dust storm video from Arizona

May 10, 2012 - 12:26 PM

Hottest Year Ever : Well Not Everywhere

May 9, 2012 - 02:38 PM

The headlines and quick national news stories all said about the same thing.  This year so far is the warmest on record in the United States and many major cities including Washington, DC.  




This data from the National Climatic Data Center.  Not only that but the last 12 months have been, "The warmest 12 month period on record"
 Sounds pretty ominous and here in Washington we have had temperatures for 12 of the last 13 months above average and the long term temperature trends in the country are rising 


  But while much of North America has been in this warm pattern, look at the temperature anomoly pattern around the globe for January-March, the latest period I could find. 


Folks in central Asia might take some of our warm pattern and it was a very cold winter in many parts of Europe where the Danube River iced over and snow fell in Venice. Actually for January to March the long term temperature anomoly around the globe was only +0.7° and was the coolest Jan.-March since 1996 according to the National Climatic Data Center where many of these graphs are from .


   What does this all mean?  Well it's important to read beyond the headlines.  The general long term global warming is still there as you can see above and many scientists think we may be in for a continuation of these large scale persistent patterns of unusual warmth and dryness in some parts of the world yet unusual cold and wetness or flooding in other parts.  Extremes becoming more probable?  Maybe so.  This coming summer in Washington?  



Right now I would not bet against this current trend.  The pattern may change, but right now I think it will be another long hot summer.  But that's another blog to come soon.  But remember with stories about global change and "record warmth" and yes, global warming . . .  read the entire story, as I've tried to give you above 


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Air-Mass vs. Supercell: A Weather Cage Match for Thunderstorms

May 8, 2012 - 07:40 PM

Well, it’s the time of the year where our weather attention turns to the possibility of severe weather… and that means possible thunderstorms and even tornadoes!

Did you know that most tornadoes emanate from a particular type of thunderstorm? Do you happen to know what the unique name of that thunderstorm is?

If you answered “A supercell thunderstorm”, then you know your weather!

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Washington DC timelapse of the morning sky and clouds

May 8, 2012 - 08:38 AM

We have about twelve hours of daylight today, and we had a few peeks of sun earlier this morning near sunrise (6:02 am), but rain is on the way for the afternoon. Enjoy this timelapse of the clouds this morning:

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'Dinosaur flatulence' and global warming: The gassy relationship

May 8, 2012 - 05:00 AM
How much did dinosaur gas have to do with early climate change? (Photo: Flickr/Son of Groucho)

Flatulence -- OK, so this is not a topic that I ever thought I would blog about, but in context, the whole story is pretty interesting.   It has to do with dinosaur gas and the climate.

In the Current Biology journal, an article posted by scientists finds dinosaur gas likely produced more methane than cows do today.  Methane is a greenhouse gas that is 20 times more powerful in trapping warmer air in the atmosphere than carbon dioxide.  Actually, cows release more methane by belching than flaculating (OK you know the common word ), but I guess we don't know if dinosaurs burped, or belched, as much as the study assumes they flaculated, but it's fun to think about.  Imagine that sound . . .from both ends.

The dinosaurs discussed in the study are Sauropods.  These are are four footed, vegetarian dinosaurs that lived during the Mesozoic age.  Since there were so many of these sauropods traveling in dense herds, during the time, the methane emissions added up.  The study determined there was about 575 million tons of methane emissions annually!  

Dinopark Münchehagen

Wondering how that compares to the methane from cows today?  Cows only emit about one fifth the amount of methane, as estimated by the sauropods.  The study concluded the methane gas emitted by the sauropods could have played a significant role in altering the climate during the Mesozoic time period.

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Next Super Moon in June?

May 6, 2012 - 03:55 PM


Boy has last night's "Super Moon" gotten a lot of press and all sorts of pictures and attention.  But it has been "Super" before and will be again.  It's just that at the time the Full Moon coincides with it's closest position to earth (the Moon's orbit is not a perfect circle) it does appear about 15% bigger than when the Moon is farthest from earth.  But guess what?  You get another chance.  Saturday night was cloudy and if you couldn't see this "Super Moon" you get a chance in 4 weeks June 4 is the next Full Moon.  This Full Moon will only be about 1000 miles farther away from us than last night's moon.  That is 0.6% farther away and the diameter of this close second to "Super" about 0.6% "smaller".  Think you can notice the difference?  We'll have to wait until June 4 . . . and hope the skies are clearer than last night.  By the way the moon is actually about 4000 miles closer to us when it is high in the sky late at night than when it is rising at 9PM on June 4.  Why does it appear so huge when it is rising.  Most agree a trick of our brain and the way we view the sky.  More here.  Keep watching the sky, day and night and especially June 4.  Let me know if you can tell Super Moon #2 from Super Moon # 2.


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Timelapse of thunderstorms in D.C.

May 4, 2012 - 02:50 PM

Check out the timelapse of the heavy thunderstorm that moved through D.C. on Friday around Noon. There was heavier activity just south of D.C. from Alexandria to Dale City. It actually became severe once it reached eastern Prince Georges County and Anne Arundel County but weakened as soon as it reached the Bay.

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Hour-by-hour weekend forecast

May 4, 2012 - 09:12 AM

There's a lot riding on the weekend forecast including events ranging from the Virginia Gold Cup to Nationals games and the Avon Walk for Breast Cancer - to name a few. So, will the weather cooperate? For the most part, I think it will. Let's start with Friday's weather then we'll jump into the details for the weekend including hour-by-hour forecasts. 

Thunderstorms are likely Friday afternoon starting around 4 p.m., and some storms may be strong and severe with gusty winds and large hail being the primary threats. If you plan to attend the Nats vs. Phillies game, be prepared for a potential delay. The storms will pop-up randomly, but I think there's a moderate chance that Nationals Park will get hit. Also, a few storms may develop into the night, but they should be more widely seperated.

Temperatures on Friday will be warm, and you'll feel the humidity in the air as well.  I'm expecting afternoon highs well into the 80s then dropping into the 60s by Saturday morning. Here's the hourly forecast:




 As for Saturday, there is a slight chance (20%) of storms both before sunrise and in the late afternoon hours.  My confidence is slim in storms developing on Saturday, and if one particular computer model is right, then no storms will develop at all, but that model is an outlier, so it's worth mentioning a minor chance. In terms of temperatures, expect morning numbers in the 60s then afternoon highs in the lower 80s with a hint of humidity. 




 As of now, Sunday looks rather cloudy in the morning with patchy drizzle and fog possible.  However, the clouds should break with sunshine by midday and afternoon. Precisely timing the erosion of the morning clouds is very difficult, but as of now, I'm expecting sunshine by 10 a.m. It will be cooler and more comfortable with lower humidity on Sunday as highs approach the mid 70s. 








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Super Moon 2012

May 4, 2012 - 05:00 AM

You may have heard about the "Super Moon" that's happening tomorrow night, but do you really know what it's all about?  Will the moon really look that "super"?  And will this "super" full moon make people act even crazier, as the folklore says?

Well, I can't really answer the second question, but I can say, for sure, it will look bigger.  In fact, the moon tomorrow night will look the biggest and brightest it's been this year -  as much as 14% bigger and 30% brighter!


So why the brighter and bigger than normal moon?  It's actually because of the lunar "perigee" in combination with the full moon.  The moon follows an elliptical orbit around the Earth.  When the moon is closest to the Earth it is called the perigee and when it's the farthest from Earth it is termed apogee.

NASA diagram

The perigee is about 50,000 km closer than the apogee.   From the image below, you can tell that during the perigee, the moon appears much bigger since it's closer to Earth.  The perigee occurs at 11:34 PM tomorrow night and the full moon is a minute later. The near perfect timing brings us the bright and big super moon.

Anthony Ayiomamitis -

A super moon isn't all that uncommon with the full moon cycle coinciding the perigee.  Last year, on March 19, 2011, we had another super moon, although it was about 400 km closer to the earth than the one we'll see tomorrow night. 

I hope this doesn't spoil the novelty of the supermoon, but it will surely be a neat sight  Try getting out to see the moon, as it rises.  Because of the "moon illusion" , the moon will look much bigger the closer it is to the horizon.  Moonrise is at 7:55 PM tomorrow night, so grab you're friends and head out for super moon gazing.  Skies should be mainly clear, which will make for a bright Saturday night! 

If you happen to miss the supermoon tomorrow night, here's when you can catch it through 2015.  Enjoy! - Dates of next full moon & perigee

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Weather Channel 30 Years Later

May 2, 2012 - 05:23 PM

It was about 1979.  Not the start of The Weather Channel, but a time when I was the meteorologist on NBC's Today Show and John Coleman was on ABC's "Good Morning America"  in addition he was also the forecaster at the ABC station in Chicago WLS-TV.  John and I met at a weather conference about the time I was moving from "Today" to join NBC here in Washington.  John teased me with this idea he was working on that he thought would really be something different and huge.  He also was working with securing funding and also working with the National Weather Service to distribute the NWS local forecasts through a system called Weather Star.  John was sure an original thinker and TWC was launched 30 years ago today.

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Gold Cup Forecast: Pastels and Pocket Squares Likely

May 2, 2012 - 03:50 PM

The 87th running of the Virginia Gold Cup races is this weekend and I'm sure many of you are wondering what the forecast holds. Temperatures appear like they will be quite warm with highs in the mid 80s by the early afternoon hours. Dew points will also be a bit of a bear though as they should lie right around the 60 degree mark making for humid conditions. Good thing you ladies will be wearing those big hats to keep the sun off and the guys will have plenty of pastels to reflect the sunlight.

Hourly forecast for Saturday

It's the afternoon hours that I am worried about. A cold front is expected to move through the region Saturday which should initiate showers and thunderstorms through the early afternoon. Storms are expected to be scattered in nature but I still worry as there is very little in the way of safe shelter at the event other than your car or the busses used to transport you there.

Be sure to check Live Super Doppler here the day of the event.

Be sure to check with the driver about where to go in the even of a storm. I would NOT plan on riding out a storm under one of those big tents that are supported by metal beams. Not only could they be struck by lightning but high winds could easily knock one of them over.

I would definitely recommend wearing some suntan lotion as I personally have been burned there every time I have gone..even once when it rained and was 60 degrees the entire time. Have fun and be safe!

You can download the ABC 7 Weather App here to help keep you on top of the forecast through the week and weekend.

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It's Already May?! Find Out How Many Months Have Been Above Average

May 1, 2012 - 07:30 PM

If you feel the temperature swings have been a little extreme lately, you're not alone!  We had a high of 50° about a week ago and today, we hit 84°!  8 out of the last 9 days of April had below average temperatures and then, the first day of May arrives with much warmer than average temperatures and the return of... humidity -- which only makes it feel that much hotter and stickier.  Look at how much warmer it was this afternoon compared to yesterday.

24 Hour Temperature Change

Despite some cooler than average temperature days to end the month of April, the month ended 1.5 degrees above average.  Now keep in mind, March ended a whopping 10° warmer than average!  The month of April was actually a little less than 2° warmer than March.  Typically March highs average 46° and April highs average close to 57°, so that means both March and April had similar average highs. 

April had 11 days below average.  Did you know that was the first time we had more than 10 days below average, since October 2011?  Another fun fact for you - with the month of April ending above average, now 12 out of the last 13 months have been above average.  That's pretty much a full year of above average temperatures!

Monthly Temperature departures

As for rain, it was pretty dry in April and has been for 2012.  April ended with a total 1.92" or rain, which was still 1.14" below average.  As for the year, well, we're still a little less than 5 inches below yearly rainfall. 

Since we didn't get as many April showers as we needed, we'll hope for more rain in May.  And after the well above average highs on this first day of May, maybe another month to add to the above-average- monthly- temperature- streak?  I think, after day one, it's a little early to start thinking about that. 

Happy May everyone! 

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