Thursday, January 17, 2013

A Likely (Fantasy) D.C. Area Snow Event

Updated 12:52AM 1/18/2013: See below.

Sterling (LWX) CWA webpage showing advisories in effect as of midnight, January 17, 2013.

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For reasons that aren't clear, Sterling LWX is keeping a winter storm watch in place for the immediate D.C. area even though the models (in particular the sh!tty NAM, which was advertising a snowstorm here) have backed off on the earlier promise of 4 to 6 inches of snow here. The current graphical map has 2 to 4 inches for D.C., but that too is kinda unlikely -- and AS EVER with this damn map when it is used, the D.C. totals drop with each successive run until nothing remains. It has been like that for the 3 winters the map has been in use.

Here is the current graphical map of the LWX CWA updated at 10:11PM Jan. 16, 2013 showing the (UNLIKELY) forecasted amounts.

Again, I don't think this is going to come to pass for D.C., but we shall see. As it is, earlier on Wednesday when the winter storm watch was raised, I sent out a bunch of weather e-mails to people I know touting this possible snow event. Now I just look stupid. (This is why I could never have been an actual "weatherman" -- the getting it wrong part.)

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Here is the discussion from 9:57PM tonight:

"A STRONG SOUTHERN BRANCH SYSTEM WILL TREK ACROSS THE SOUTHEASTERN STATES TONIGHT BEFORE MOVING OFF THE MID ATLANTIC COAST BY LATE THURSDAY NIGHT. DIFFLUENCE ALOFT INCREASES AS THE SYSTEM MOVES BY TO THE SOUTH ON THURSDAY."

"THE OLD FRONTAL BOUNDARY MAY PROVIDE A FOCUS WHEN COUPLED WITH STRONG VERTICAL MOTION FOR A BAND OF HEAVY SNOW TO DEVELOP THURSDAY. THE BEST POTENTIAL FOR THIS TO OCCUR IS FROM HIGHLAND COUNTY TO CHARLOTTESVILLE. GIVEN THE DYNAMICS A PERIOD OF SNOWFALL RATES OF 2+ INCHES PER HR WOULD BE POSSIBLE IN THIS BAND."

"THE MAIN FORECAST PROBLEM IS HOW FAR NORTH AND EAST THE BAND WILL MOVE ... AND WHAT WILL BE THE IMPACT FOR THE DC AREA."

"THERE WILL BE A BIG DROP OFF OF SNOW ACCUMULATION NORTH OF THE BAND. THE NAM KEEPS IT FARTHEST SOUTH ... WITH LITTLE IMPACT FOR THE DC AREA. THE GFS WOULD SUPPORT A FEW INCHES OF SNOW FALLING IN THE METRO AREAS WHILE THE EC...UKMET AND ARW APPEAR TO BE COMPROMISE SOLUTIONS. THE 21Z SREF ALSO CAME IN SOMEWHERE IN-BETWEEN."

Above: The shitty 0Z 01/17/2013 NAM solution for 850mb temps, MSLP, and 6-hr precip. valid at hour 33 (09Z 1/18/2013) showing a Sue Palka fantasy world where all snowfall misses D.C.

"THERE IS CONCERN THAT TEMPERATURES WILL BE TOO WARM FOR SNOW TO ACCUMULATE RAPIDLY ON ROADWAYS ... BUT AN INCH OR TWO CAN NOT BE RULED OUT IN THE LATE AFTERNOON AND EARLY EVENING. THE CURRENT THINKING IS THAT AN ADVISORY TYPE EVENT REMAINS POSSIBLE ... SO THE WINTER STORM WATCHES WILL BE LEFT IN PLACE THOUGH PUSHED BACK A FEW HOURS. WARNINGS WILL REMAIN IN PLACE WHERE THEY HAVE BEEN ISSUED. PLEASE CONTINUE TO MONITOR OUR FCST AS THIS SCENARIO UNFOLDS."

In short, there is almost NO chance that this will be the big snowstorm I was hoping for. In any event, ext week it is forecasted to be genuinely wintry cold with sub-freezing highs (around 30F at KDCA) and lows in the teens although dry.

Oh, yes, also, there was a bit over 1" of rainfall in the past two days at the three regional airport climate stations (KDCA, KBWI, and KIAD), which was good.

OK, that wraps up this entry. I may not post another one until Friday night. I need to post a political-themed entry at some point since there are some topics I want to discuss.

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Updated 12:52AM 1/18/2013: OK, as expected, we got zilch in D.C. I started an entry about this but it's just too late to finish. I plan to post it tomorrow along with my regular Friday night musical interlude.

--Regulus

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