From the ABC 7 Weather team

Archive for February 2012

Sunday's snow forecast still very unsettled

February 16, 2012 - 09:11 AM
Only two inches of snow have been measured so far this winter at Reagan National Airport. (Photo: Jay Westcott)

Update 12pm: Per 12z data, my Snow Excitement Factor has increased to a 3.5 out of 10.  Precipitation looks more likely (60%), but the type of precipitation is a big question mark. It's turning into a situation where we shift the focus from whether or not we get hit to what type, when, where and how much.  Model guidance has had more difficulty with P-type more than anything this winter.

Previous Discussion:

The likelihood of a weekend storm affecting D.C. has increased. Though let me know what you think of this as Sunday’s forecast: cloudy & breezy with a chance of rain and/or snow and/or sleet or no precipitation at all. I wish I could get more specific, but that’s the best we can do at this point. Model guidance has come a little closer together in their solutions for the Sunday event, but the guidance is still far from agreement.

I’d love a whopper snowstorm as much as any other snow enthusiast, but I’m still not confident in a big hit of snow just yet. I’d give it a Snow Excitement Factor of 2 out of 10 for now, which is hopeful but not optimistic. Sure, the predicted interactions in the atmosphere and possible storm tracks are more similar amongst the models than before, but there is still much uncertainty, so we need to wait and see a little longer.

Some of the individual models have flip-flopped, but at least there seems to be more of a trend and convergence in solutions compared to what we had to work with yesterday. However, it’s important to note that this does not mean the models will continue to trend together. I’ve seen it many times where they come close together then quickly diverge again.

Another important factor is what I mentioned yesterday, and that’s persistence. It’s fair to say that the models have had a rough time so far this winter, so I hold little stock in them for these dynamic situations. Also, it’s tough to get the necessary phasing of the northern energy along with the southern energy in these La Nina winters, but it’s not impossible and does happen.








As usual, the exact track of the storm will play a major role on the type and amount of precipitation we receive, and the path of uncertainty and various model suggestions for the storm track are shown in the posted graphics. Should the storm system take the more southerly track, it will have less of an impact on Washington, but a more northerly track would lead to bigger impacts and possibly a solid hit of snow.

This storm hasn’t even organized yet, and we’re trying to predict the outcome in a very unpredictable winter.  There have been winters where this was possible ('09-'10), but recent history has proven otherwise. 






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Why to get away from light pollution (Video)

February 15, 2012 - 05:58 PM

This spectacular video has already been watched around 130,000 times but I think we can push it up to at least 150,000. This is really cool, enjoy! Check out the website for more information on how he made this and other videos. You can also find them on Facebook and Twitter. If you think I am promoting him then I guess I am because this is really awesome!

Temporal Distortion from Randy Halverson on Vimeo.

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Adding to the chatter of a weekend snowstorm

February 15, 2012 - 07:22 AM
How likely is a wallop of snow this weekend? Adam Caskey isn't too optimistic. (Photo: ABC7)

Here we go again. All it took was a few long range model runs to start the buzz and get folks worried about a weekend nor’easter. Don’t get me wrong, I like the chatter about weather and enjoy a challenging forecast, however, it remains too early to have a good idea of what will happen.

Nevertheless, provide an adequate degree of certainty regarding the possibilities.

Let’s not forget history too as this scenario has been the story of our winter due to our given weather pattern. There have been several could-be snowstorms, and what do we have to show for it? Only a mere 2.0” at Reagan National Airport (DCA) and 3.7” at Dulles Airport (IAD) so far this winter.

I am an absolute snow lover, and I’d love to put snow in the forecast for the weekend, but I simply can’t do that yet because it’d just be a “wishcast,” which does no good. I do think snowfall is a slight possibility this weekend in the D.C. area, however, I currently believe it is unlikely.

It’s possible but not probable. As frustrating at it may be, it's too soon to tell. The ingredients are there, they just have to be perfectly mixed, which has proven difficult this winter. As a matter of fact, I think it’s irresponsible to start talking about the snow potential for Sunday as early as Monday or Tuesday in the given weather pattern this winter.

Our path of uncertainty given the current model tracks

That said, I still think it’s too early, but I’ve fielded too many inquiries to wait. Two years ago it was a different story as the prevailing pattern was more predictable and model guidance had a good track record over the course of the winter. Ah, the good old days! 

As WTOP/ABC7 meteorologist Chris Naille, put it, "There are more questions than answers at this time especially considering we are talking about a system that is over 4 days away.

"At this stage, no one can responsibly forecast this potential event beyond stating that Sunday looks to feature mostly cloudy skies, gusty winds and cooler temperatures."

I’ll try to give you a quick rundown of a few model trends without getting too complicated. First of all, the ECMWF (Euro) model was recently gung ho about a nor’easter hitting Washington over the weekend but has since laid off that solution as of the 12z Tue and 00z Wed model runs, which now keep the storm track and all precipitation to our south.

Typically this is a fairly reliable model, but has proven otherwise this winter. The 00z Wed GFS came into line with previous ECMWF runs by phasing two systems and slamming us with the storm, but this also had a big spread in the ensemble mean, which is fairly common this far out. Not to mention the GFS indicated a higher chance of rain than snow.

Now the latest (06z) GFS is trending farther south and looks less ominous. So far it seems as though the CMC (Canadian) has been the most consistent indicating a southerly storm track and just a glancing blow or a close call with little to no impact. Due to persistence, I’m not holding much stock in any individual solution at this time and have very little confidence in a snowstorm despite desperately wanting a whopper.

As of now, I’m keeping my weekend travel plans but also closely watching the trends.

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Heaviest snowfalls after Valentine's Day in D.C.

February 14, 2012 - 04:06 PM

A lot of weather weenies have been wishcasting a snow storm this weekend as some model guidance hints at the potential of a coastal low passing by on Sunday. I, for one, am one of the wishers! I mean, come on, 2 inches for the entire winter? Give me a break! Instead of blog about the possibilities of what could happen with such low confidence in the models this winter, I decided to check and see what big snowfalls occurred this late in the winter in the D.C. area.

Top 5 Heaviest Snowfalls after February 14th in Washington, D.C.

1) February 19th, 1979:  14.0 inches (also had 4.7 inches on the 18th for a whopping 18.7 inch storm)

2) February 16th, 2003:  13.3 inches

3) February 15th, 1958: 12.9 inches

4) March 29th, 1942:  11.5 inches

5) March 4th, 1909: 9.8 inches

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Some Snow This Weekend On A Historic Weather Anniversary

February 11, 2012 - 05:00 PM

It looks like we'll get a taste of some true winter weather this weekend.  A bit of snow and a cold blast will move into the region.  When I say a "cold blast" in our area, we'll experience temperatures, finally, below average.  Highs will be in the 30s with overnight lows falling into the 20s.  Couple the colder air with the gusty winds and wind chill values will be in the teens.


It will certainly feel cold, especially compared to the relatively mild winter we've experienced thus far.  Now, we won't break any records with this cold snap, and trust me, that's a good thing!  As I've been forecasting this week, I've noticed climate data indicating record low temperatures below 0°.  The high and low records for Feb. 9-12 all occured in 1899, during the Great Arcitc Outbreak.  Here's a map that shows the temperature and snowfall from February 10-11th (more on the blizzard below).

Barbara M. Watson

Right here in D.C., low temperatures fell to -15°, which remains the coldest temperature on record in D.C. to date.  Not only did D.C. get hit with intense cold, but so did much of the Eastern United States.  February 1899 startred off with a two week period of extremely cold weather.  All time record minimum temperatures were set in 12 states from the Central and Southern Plains, to the Southeast, and right here in D.C. 

The Arctic Outbreak culminated with a strong low pressure system that would go down in history as the Great Blizzard of 1899.   Here's a surface map from 1899 on February 12th. 

"Weather and Forecasting" - Kocin, Weiss, Wagner

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The past 14 years of weather seen in 33 minutes

February 10, 2012 - 03:38 PM

And away we go...

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Wintry mix to snow likely to start the weekend in D.C. (Video)

February 10, 2012 - 11:11 AM

A complex weather system will make its way east today through the Midwest and Ohio Valley bringing with it light snow and rain showers. I say this system is complex because it's not just one area of low pressure, but the combination of a strong polar cold front combining energy with a disturbance that has tracked east from the Plains. Energy will then transition to a coastal low off the Carolina coastline Saturday morning which should then rapidly intensify as it heads northeast over the Atlantic. Getting a little more complicated now? Here's our latest thoughts in our video update. 

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VIDEO: Great Timelapses Of Morning Sun & Melting Snow

February 9, 2012 - 09:00 PM

Take a look at a few timelapses from earlier today courtesy of our WeatherBug cameras from across the region.




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Another chance for a wintry mix into the weekend (Video)

February 9, 2012 - 04:00 PM

Wednesday brought such piddly amounts of snow which got the twitter folk hashtagging #flurrygeddon. We think more of the same will be experienced Friday night into Saturday morning as we head into the weekend. This system will definitely pack a little more of a punch though as a very strong cold front dives into the region and a coastal low looks to intensify off the east coast. Here is a video update on the system-at-large which will visit us for the start of the weekend.

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Did You See Enough Snow Today? This May Make You Feel Better

February 8, 2012 - 10:30 PM

The whimpy system that moved over our area today didn't leave too much for snow lovers.  I have to say, I was a little disappointed we didn't see any flakes in DC.  Folks North and West of the metro area did get a bit of snow to, at least, satisfy the "winter wonderland" feeling.  Here's a picture from one of our WeatherBug cameras, earlier this afternoon, in Ijamsville, MD.

WeatherBug Camera

Snow totals were slim to none across the region.  Smithsburg, in Frederick County, MD, picked up a whopping two inches (can you sense a little sarcasm from the snow lover here?).  Most other spots, that saw snow, received anywhere from a trace to 1.5 inches.  Here are the latest snowfall reports from the National Weather Service.

I know some people were perfectly content with the little to no accumulations today.  Others were hoping for more.  Regardless of how you feel, let's take a quick trip back memory lane to two years ago, almost to the day, -- SNOWMAGEDON! 

The same areas in Frederick that saw between 1 and 2 inches of snow today were buried under 25 inches of snow two years ago today.  Here's a map of the total snowfall during this storm.


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Full Snow Moonrise over DC

February 8, 2012 - 03:13 PM

I recorded this last evening though our new HD camera looking over the National Mall and Washington.  It is the Full Snow Moon.  The moon rises with an orange glow due to scattering of the blue part of the light (that's the reason the sky is blue) and reddish light is transmitted.  As the moon gets higher it becomes a bright white and you can also watch again and see the reflection of the moon on the Potomac River.  Enjoy



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Live Blog: Snow in the D.C. area today

February 8, 2012 - 09:44 AM
Snow has begun to fall and it may affect tonight's commute (Photo: Ben Rice) (Photo: Brad Bell)


Final Update - Pretty much all of the rain/snow is wrapping up around the region.  Look for clearing skies overnight and falling temperatures.  Watch out for icy spots on the roads early tomorrow morning. 


Latest image of Snow Machine:  Temperatures still above freezing in the metro area.  Rain/Snow will wrap up within the next few hours.  Maybe a few wet snowflakes for DC, as the moisture tapers off and pushes East. 

Live Doppler: 5:20PM


Snowfall Reports

Thurmont, MD - 1.5 inches

Frostburg, MD - 1.2 inches

Martinsburg, WV - 0.3 inches on the grass

Waterford, VA (In Loudoun Co.) - 0.1 inches

Have a report? Let us know on Facebook or Twitter.


Since the snow hasn't been that much of a factor, temperatures are above freezing and this event should end in the next few hours, the Winter Weather Advisory has been cancelled for Montgomery, Loudoun and Fauquier Counties. It is still posted for Frederick County in MD and points west, the Panhandle of WV and Clarke and Frederick Counties in VA until 8pm.


Everything is beginning to changeover to snow in the 270 cooridor near Germantown and Gaithersburg and points west. Also, snow is beginning to mix in around Dulles Airport and points west into Loudoun County, VA. Temperatures are around the freezing mark north and west of D.C. and some light accumulations will be possible through the remainder of the afternoon in the grassy areas. A few slick spots will be possible on lesser traveled roadways so be careful out there as you make your way home. Snow should come to an end later this evening.


Video Blog time! Check out the latest cameras across the region as well as my latest thoughts on the snow... or lack thereof...


Keep an eye on the D.C. road temperatures this afternoon and evening closer to the evening rush. This could be worth a bookmark!

Some light rain will move into the D.C. Metro area over the next hour or two. We still think it will change over to some very light snow later this afternoon and evening before coming to an end. Light snow remains over the Winter Weather Advisory area but temperatures are still in the low to mid 30s. 


@MADUSWX has reported light snow in Gaithersburg with visibilities around 2 to 3 miles. 

@ArlingtonDES has reported the county has entered Phase 1 Alert and snow crews will handle the snow as it comes.

It may be a few hours before snow even hits the D.C. Metro area. Could even be closer to 4pm until D.C. sees its first flakes. North and west of town, light snow has been falling but only sticking in the grassy areas. Please tweet me at @alexliggitt if you happen to see anything sticking to the roadways. Send me some pictures too! Thanks for your help!


Light snow is now being reported in Frederick, MD and west of the Blue Ridge from Hagerstown, MD to Winchester, VA along the I-81 cooridor. Light accumulations in the grass will be possible with temperatures still above freezing. Road temperatures are mainly in the 40s.


Did the snow moon foreshadow the light snow?


Snow is moving east into Loudoun and Frederick counties at this time. It should reach western Montgomery and Fairfax by Noon. This is light snow and should just make for some wet roadways. Temperatures are all still in the mid 30s. There will also be numerous breaks in the snow through the afternoon.


Here's the Winter Weather Advisory put out by the National Weather Service. It runs until 10pm tonight. This is where the highest likelihood for measureable (1-2") of snow is possible.

Timing seems to be shaping up for a start in the early afternoon in the D.C. Metro, a little earlier for Fairfax and Montgomery and later farther to the east.


From @WTOP, federal employees in the DC area have the option for unscheduled leave or telework.


The first flakes were just reported in Hagerstown from twitter user @JY_LMAWW. Please send me any pictures if you can to @alexliggitt on twitter or to Adam Caskey will also take pictures on his facebook page and display them on the Noon newscast! be sure to check out Live Super Doppler through the day to see where the snow is and check out some of the cameras to check out the local road conditions.


The official ABC 7 Weather Team's Snow Forecast



Here is the Stormscan as of 8:45am this morning

An area of light snow will move towards the region through the remainder of the day, bringing light snowfall accumulations later this afternoon. With temperatures currently in the upper 30s to near 40 degrees in the D.C. Metro, we are hopeful that much of the snow will melt on contact with the roadways but do expect some isolated slick spots or slushy areas to develop later this afternoon. The area with the biggest concern will be north and west of D.C. where the potential for 2 or more inches of snow exists. Check out the latest camera image from Frostburg, MD in our WeatherBug network where it has already begun to snow!


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What Will It Take For This Winter To Be The Warmest On Record?

February 7, 2012 - 03:00 PM

We're just a few days into February and still talking about the milder than average temperatures.  So far, all days in February have been above the 37° high/low average.  Take a look at how much warmer than average temperatures were across much of the Eastern U.S. on Monday.

Winter 2011/2012 (using the meteorological winter start date - Dec.1st), as of February 6th, has been above average.  Here's a chart that shows where temperatures stand. 

Keep in mind, this data is only through February 6th.  Through this date, Reagan National is 5.7° warmer than average.  What's the average?  An average winter in D.C. is 38.2°.   If February ended today, it would be the third warmest winter with an average of 43.9°.  The warmest winter in D.C. history was in 1932 with an average of 44.6°. 

Obviously, February is not close to being over, so we've still got some time to go before we know where this winter will fall in comparison to others.  But let's have some fun and see what it would take for this to be the warmest winter ever! 

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Light snow possible for the D.C. area

February 7, 2012 - 11:40 AM

Another weak system approaches the region in a winter that has featured 1.7 inches of snow. I would say that we may be able to double that number on Wednesday as the low moves through the region but I think that would be pushing it as no matter what the forecast says, the outcome has been less each and every time this winter. We are forecasting snow however, with up to an inch possible, mainly on grassy areas.

12Z Futurecast snowfall predictions

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Watch Out for the Snow Moon

February 7, 2012 - 05:03 AM

Moonrise is at 5:44 p.m. this evening.  A perfect time of the year (not too early . . .not too late) to see one of the great tricks there is. How big do you think the rising Full Moon is?  Why is it so huge when it rises tonight but then looks smaller high in the sky around midnight?  After all, the Full Moon is really 4000 miles closer to us (the earth's radius) at midnight than at moonrise.  Shouldn't it look larger overhead when it is closer than on the horizon?  Yes it is but no it doesn't.

OK enough of trickery by me.  A little explanation here.

Suppose it's a nice day with a deep blue sky and some fluffy clouds. Now look up at the sky. The sky and clouds above you appear to be closer than the clouds far away. And they are. Those fluffy clouds right overhead are about a mile away and the clouds on the horizon are about three miles away. We see the sky sort of flattened like a saucer, like this: 

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Relatively quiet week ahead for the D.C. area (Video)

February 6, 2012 - 03:29 PM

The month is already well above normal as far as temperatures are concerned and there is no real threat of that changing this week. With highs only in the mid 40s this weekend, temperatures have been on the rise in the D.C. area today, making it to the lower 50s through much of the area. This is where they should stay tomorrow before falling as a weak system passes through the area on Wednesday. Here's more in my latest afternoon analysis.

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This weekend marks two-year anniversary of “Snowmageddon”

February 4, 2012 - 01:07 AM

You often hear the expression, “What a difference a year makes!” Well, we can say this year, “What a difference two years makes!” In 2010 at this time, we were scrambling to find shovels and snow removal equipment for what would be a one-two winter punch that would plow through the record books and get termed "Snowmageddon."


It started out with a weak disturbance moving in from the Southwest and southern Rockies that became stronger once it moved into the Central U.S. A healthy 992 mb low pressure developed along its southern periphery on the Gulf Coast with enough lift to promote snowfall as far north as the D.C. region. As the upper energy and surface low transitioned to the Mid-Atlantic coast, snowfall rates increased overnight on the 5th into the 6th.

This storm sure found its way into the record books by the time it ended on February 6th.

February 5-6, 2010 Storm Snowfall Amount
Dulles International: 32.4 inches; two-day snowfall record
BWI Thurgood Marshall: 24.8 inches; two-day snowfall record
Reagan National Airport: 17.8 inches; second highest two-day snowfall record

The two-day total of 17.8 inches at Reagan National Airport was less than one inch away from the 18.7 inches from the February 18-19, 1979 storm and not far behind the infamous “Knickerbocker” storm that dropped 26 inches in two days from February 12-13, 1899. At Dulles International, 32.4 inches wiped out the previous two-day storm record of 23.2 inches on January 7-8, 1996 while 24.8 inches at BWI Marshal barely beat out the two-day storm record of 24.4 inches.

Mother Nature wasn’t done just yet! A strong storm came barreling out of the Mid-Mississippi Valley on February 9th before developing another impressive 992-mb low off the Mid-Atlantic Coast. Unlike the first storm just days ago, the winds were stronger with this storm (35 to 40 mph), making it more like a true blizzard for the region. The winners in this storm included Frederick, Baltimore, Howard and Carroll Counties where 22 to 26 inches combined with gusty winds to produce 6-foot drifts.

Here are the snowfall totals for the three major airports in our region:

February 9-10, 2010 Storm Snowfall Amount
BWI Marshal: 19.5 inches
Dulles International: 9.3 inches
Reagan National Airport: 7.1 inches

These two storms helped push the monthly snowfall total to 32.1 inches; 21 inches were on the ground at Reagan National at one point after the storms ended by February 11th. Dulles International had a starting 46.1 inches for the month while BWI Marshal recorded a whopping 50 inches and a snow depth to 34 inches right after the storm on the 11th.


(Heavy snow is piled up at the National Weather Service Office in Sterling, Va. Photo courtesy of the NWS Sterling office)

This by far puts to shame the winter we’ve had this year. The seasonal total so far is 1.7 inches, which is 9 inches behind par.

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Potential for snow in the weekend forecast

February 3, 2012 - 12:07 PM

Check out some of the huge snowfall totals coming out of the Denver Metro area this morning. There's even a live video feed coming out of Fox 31 in Denver.

Black Hawk, CO - 28.5 inches          Pinecliffe, CO - 34.5 inches

Denver, CO - 10.5 inches          Conifer, CO - 27 inches         

The snow will finally come to an end there by tomorrow morning and that same system will move across the Central Plains and into the Mississippi Valley region tonight. Ok, enough about Denver, I know you all want to know about our very own chances for snow closer to home.

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D.C. area quiet; Denver area blizzard (video)

February 2, 2012 - 02:50 PM

Yes, yes, it's not 70 degrees outside anymore but it's still hit the upper 50s! Showers moved through the region this morning dropping a quarter of an inch or more of rain in some areas but clouds have moved to the east to make for a nice afternoon. So what's up with the weather for the end of the week and into the weekend? High pressure will continue to slide into the region tonight and plenty of sunshine will experienced Friday. The weekend will bring changes, however, as an area of low pressure moves from the Rockies towards the Mid Atlantic.

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Winter scene from above and a lapse of storms in Florida (Video)

February 1, 2012 - 03:53 PM

Two good finds today on the interweb as a kid in the Seattle area used his remote controlled plane to film the winter storm a few weeks ago and our friend at WeatherBug steered me in the right direction to do a video timelapse of a cool looking storm moving through Pensacola, FL. As I like to attribute the people I find these things from, thanks to Morgan Palmer for tweeting the first video, also shown on Great story on the remote controlled plane too. The kid is a 17-year old still in high school in the Seattle area. Why didn't I think to do something cool like that when I was a kid???

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