Monday, February 16, 2015

Stopping By This Blog on a Snowy D.C. Evening -OR- The Little KDCA Snowboard That Probably Just Can't

The view from my Hampton Courts apartment overlooking my little section of Washington, D.C., on the start of a snowy night, 7:09PM February 16, 2015.

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So our D.C. area snow "event" has started in the form of a forecasted moderate snowfall on the order of 6 to 8 inches across the immediate Metro D.C. and Baltimore areas and possibly more to the south owing to the track of the low. It is quite cold with surface temps around 15F and 850mb temps also cold enough to support snow-to-liquid ratios of 15-to-1 and maybe even higher.

Expected snowfall for the Sterling (LWX) county warning area (CWA) from 12PM EST February 16, 2015 through 1PM EST February 17, 2015 in an image generated at 3:40PM EST February 16, 2015.

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A complex low pressure system presently over the Deep South (Louisiana / Mississippi) will track toward the North Caroline Outer Banks with a broad swath of snow and other wintry precipitation. There are widespread winter storm warnings from Kentucky and Tennessee to the Tidewater area and north into the D.C./Baltimore area as well as southern New Jersey.

A map showing National Weather Service advisories in effect as of 2302UTC (6:02PM EST) February 16, 2015.

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A close-up of the same map from above looking at the eastern U.S.

This image doesn't include the legend for the different colors. The hot pink (or it is magenta?) shading represents winter storm warnings and the purple-blue signifies winter weather advisories.

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This is one of those rare times when all of Maryland is under a winter storm warning EXCEPT Allegany and Garrett Counties (they have winter weather advisories). (Ditto the Boston area not being under any weather advisories, but in this case, that's a bit of mercy for those folks.)

Sterling (LWX) CWA advisories as of 5:49PM EST February 16, 2015.

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The Capital Weather Gang has a very good overview in this entry (link embedded): Snow arriving, sticking immediately and turning heavier tonight (UPDATES).

CWG really is an excellent resource in these situations. Jason Samenow, Wes Junker, and the others really do an incredible service in how they present this information to the public.

Capital Weather Gang snow forecast map for the region for the February 16 - 17, 2015 event.

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Oh, and of course, the National Weather Service -- including our very own Baltimore/Washington NWS Forecast Office ("LWX") in Sterling, Virginia -- is always the unsung hero of these situations.


Theirs is real weather forecasting, not Jim Cantore showboating, grandstanding, and acting like some jackass American version of Crocodile Dundee doing live shots outside the Shoney's off the interstate in between commercials for gold bullion, pharmaceuticals of all sorts, Toyota Tundra SUVs, and promos for unwatchable Weather Channel reality TV programming.

The intersection of V Street and New Hampshire Ave NW, Washington, D.C., 1:59PM Feb. 16, 2015.

I was walking to the gym when I took this. It had yet to snow and yet, oddly, the streets were all already "white" for reasons I can't quite determine. It has been quite cold the past few days and there was a sheen of ice and snow that is mostly gone and the streets are actually dry. I suppose it could be from all the toxic rock salt poured everywhere, but that doesn't explain the widespread uniformity of the whiteness.

If anyone has an explanation, please feel free to chime in.

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Here is the LWX discussion from 3:41PM EST this afternoon in terms of snow amounts. I've broken up the text with additional pictures.

MODELS HAVE BEEN DANCING AROUND THE TOTALS...WITH THE ECMWF/UKMET ON PREVIOUS RUNS HAVING THE HIGHER VALUES. TODAYS 12Z MODEL RUNS THOUGH COMING INTO BETTER AGREEMENT AND AS SUCH...CHOSE A BLEND OF THE WPC... GFS AND ECMWF TOTALS.

USING A 15:1 RATIO...THIS KEEP 7 INCHES AND MORE SOUTH OF THE DC TO ELKINS LINE...WITH BETWEEN 10 INCHES AND A FOOT EVEN ACROSS HIGHLAND COUNTY AND ST MARYS COUNTY. TO THE NORTH... AROUND 6 INCHES IN THE BALTIMORE METRO...AND 4-5 INCHES ALONG THE MASON-DIXON LINE. IF THE SLIGHTLY HIGHER RATIOS DO COME TO FRUITION TO THE NORTH... COULD SEE HIGHER AMTS...POSSIBLY ELEVATING THE ADVISORY TO A WARNING. WILL LET SUBSEQUENT SHIFTS MONITOR THE TREND AND MAKE THAT DETERMINATION.

NASA visible satellite image of the eastern U.S. showing the storm system in question, February 16, 2015.
 
I suspect this image is from NASA's Aqua satellite, although I'm unsure of the time.

As an aside, did you know that according to Teabaggers everywhere and those corporate oligarchs who troll them endlessly in their "natural home" of the GOP, it's a satanic and/or Socialist conspiracy when you take satellite pictures of the Earth??

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THERE WAS SOME UNCERTAINTY ON HOW QUICKLY THE PCPN WOULD MOVE IN BASED UPON A VERY DRY AIRMASS IN PLACE. HOWEVER...MANY SITES OVER CENTRAL VA WITH DEW PT DEPRESSIONS OVER 20 ARE REPORTING MEASURABLE SNOW. AS SUCH...THINKING ALL AREAS SHOULD BE REPORTING SNOW BY 00Z THIS EVENING. BEST FRONTOGENETIC FORCING ALIGNS ACROSS DC INTO NORTHERN VA AND SOUTH...GENERALLY BETWEEN 03-10Z...SO KEEPING THE MENTION OF MODERATE TO PERIODS OF HEAVY SNOW OVER THESE AREAS DURING THIS TIME.

Sterling (LWX) NWS radar in enhanced base reflectivity mode, 6:09PM EST February 16, 2015.

The "smoothness" of the greens and blues are indicative of snowfall.

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IT ISNT OUT OF THE QUESTION THAT RATES OF ONE INCH AN HOUR COULD OCCUR DURING THIS TIME AS WELL. THE AXIS OF HEAVIEST PCPN WILL EXTEND WEST-EAST ACROSS DC FOR THE FIRST HALF OF THE NIGHT...THEN PIVOT AND ALIGNING MORE FROM BALTIMORE TO DC FOR THE LATTER HALF OF THE NIGHT.

The Sterling (LWX) NWS radar in enhanced composite mode, 6:27PM February 16, 2015.

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TUESDAY...
LOW PRESSURE PUSHES OFF THE CAROLINA COAST TUESDAY MORNING. LINGERING LIGHT SNOW REMAINS POSSIBLE DURING THE MORNING HOURS...MAINLY EAST OF THE I-95 CORRIDOR. SNOWFALL TOTALS AFTER DAYBREAK MAINLY LESS THAN AN INCH AS THE LOW PULLS AWAY...TAKING THE PCPN TO THE EAST. NW FLOW SETS UP BEHIND THE LOW...SO EXPECTING TO SEE INCREASING COVERAGE OF UPSLOPE SNOW SHOWERS ALONG THE ALLEGHENY FRONT. BY THE AFTN...DRY EVERYWHERE WITH THE EXCEPTION OF THE UPSLOPING SNOW SHOWERS. HIGHS EXPECTED TO PUSH INTO THE UPPER 20S TO LOWER 30S. ATTENTION WILL THEN TURN TO THE BITTERLY COLD TEMPERATURES MOVING IN FOR THE SECOND HALF OF THE WEEK.

The alley off the 1400 block of W Street NW Washington, D.C., 5:07PM February 16, 2015.

I was walking home from the gym when I took that picture. That is St. Augustine Catholic Church looming up nearby.

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Speaking of those bitterly cold temperatures, the LWX discussion includes this important tidbit for later in the week:

.CLIMATE...
A PROLONGED PERIOD OF EXCEPTIONAL COLD IS FORECAST LATER THIS WEEK. BELOW IS A LIST OF RECORD COLD TEMPERATURES FOR OUR THREE MAIN CLIMATE SITES FOR FEB 19 AND 20 /WHEN THE COLDEST IS CURRENTLY ANTICIPATED/.

FEB 19 REC LOW REC LOW MAX
DCA 4 (1903) 16 (1903)
BWI 5 (1903) 19 (1903)
IAD 7 (1979) 28 (1993)

FEB 20
DCA 8 (1896) 18 (1896)
BWI 4 (1979) 18 (1896)
IAD -2 (1979) 26 (1972/1966)

ADDITIONALLY...THE LAST TIME WASHINGTON DC /DCA/ WAS BELOW ZERO WAS ON JANUARY 19 1994 /-4 F/. THE LAST TIME BALTIMORE MD /BWI/ WAS BELOW ZERO WAS ON FEBRUARY 5 1996 /-1 F/. IT IS NOT OUT OF THE REALM OF POSSIBILITY FOR EITHER OF THESE SITES TO DROP BELOW ZERO THURSDAY NIGHT...AS SOME GUIDANCE SUGGESTS.

My own thoughts are that for crappy climate station KDCA to drop below 0F is quite incredible given that it's little micro-climate is more representative of Norfolk / Newport News.

A word to the wise: the Sue Palka-Cabra Creature is NOT HAPPY with this forecast.

There she is ...

ROAR!

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OK, that's all for now. I'm not sure what to do this evening. I could go to Larry's Lounge (again) or over to Jamie and Jenny's (they have some Monday night game night event). Or I could do both. I went to the gym already (as I had off today for the Washington's Birthday / President's Day Federal holiday) and had a good workout. Last night was fun with Nick, although too much drinking ensued, especially at Larry's Lounge where we eventually ended up and met Gary.

Snowy sidewalk view in the 2000 block of 15th Street NW, Washington, D.C., 5:09PM February 16, 2015.

I was walking home from the gym when I took this picture but detoured to the little Best DC Supermarket where I frequently shop. Its' not cheap but it's super convenient to my apartment, and it has some stuff I can't find elsewhere.

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Oh, yes, my radiator -- which, uncharacteristically, I've had to turn on the past few days -- was this morning spewing a fine mist of scalding water from its little outlet vent. This indicates that the pressure in the radiator is too high as a result of the building's boiler probably being cranked up too high. I had to turn the radiator off (courtesy the relatively new valve installed last year). It's on now and hissing away but not spewing anything. I'll turn it off before I leave the apartment.

OK, that really is all for now. I'll post the snowfall totals once the system is over. Anyone care to have a high-low bet with me on how shitty low is KDCA's snow total?

--Regulus

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