NWS: Chance Of Christmas Snow Here – 50/50

 

December 21, 2010

Well, we sure can’t say we haven’t had a white Christmas in ages. Our Dec. 18-19 blizzard last year left plenty of snow on the ground to make the place look like Santa’s North Pole workshop. But there weren’t any flakes in the air. And that’s what all the ads have taught us to expect. Right?

(Actually, we had rain, more than and inch-and-three-quarters on the 25th and 26th.)

So that’s what makes the current forecast so encouraging. The NWS forecast office in Sterling, Va. has posted chances for snow right through the weekend – 30 percent Christmas Eve, and 50 percent Christmas Day and Christmas night, and 40 percent on Sunday.

That’s no guarantee, of course. Although the storm that they’re watching is already making landfall on the West Coast with a ton of rain and snow for those people, its precise track remains up for debate amongst the computer models. Some runs bring us a major storm. Others bring us … well, sunshine.

Here’s the NWS discussion:

MEDIUM-RANGE GUIDANCE STILL IN GENERAL AGREEMENT WITH A COASTAL LOW
PRESSURE MOVING UP THE EASTERN SEABOARD FOR THE CHRISTMAS WEEKEND.
HOWEVER…EXACT EVOLUTION INCLUDING TIMING AND TRACK DETAILS OF THE
STORM SYSTEM ARE UNCERTAIN AT THIS TIME.

“LATEST MODELS ARE TRENDING TOWARD AN OVERALL SLOWER SOLUTION. HAVE ACCORDINGLY TRENDED SLOWER WITH ONSET OF [PRECIPITATION] FRIDAY NIGHT. THE FASTER GFS AND ENSEMBLE SOLUTIONS HAVE THE MAIN IMPACTS FROM THE COASTAL LOW ON CHRISTMAS DAY WHILE THE SLOWER ECMWF/CANADIAN HOLD THE BULK OF THE SNOW OFF UNTIL SAT
NGT INTO SUN.

“ALSO…ANY SHIFTS IN THE TRACK OF THE COASTAL LOW WILL PRODUCE SIGNIFICANT CHANGES TO POTENTIAL SNOWFALL AMOUNTS. AT THE MOMENT,  IT APPEARS THAT THE LOW WILL TRACK CLOSE ENOUGH TO THE REGION THAT PEOPLE SHOULD CONTINUE TO MONITOR THE LATEST FORECASTS AS DETAILS BECOME MORE CLEAR CLOSER TO THE EVENT…ESPECIALLY BECAUSE THIS COULD IMPACT THE HOLIDAY WEEKEND TRAVEL.”

Eric the Red has checked in this morning. The Baltimore meteorologist sees the uncertainty in the model runs, and persistence in our cold, dry pattern. So he’s being cautious:

Until I see a high building over New England, I’m gonna lean away from a Christmas snow storm… but obviously, it is still several days away.  If there’s one thing the snow camp has going for it, it is that the storm more or less already exists off the US west coast… so it’s not like we’re waiting for something to form.  It will be very trackable, which in turn should help me get a clue as the week unfolds.”

AccuWeather.com says:

The roadblock from last weekend’s storm in the Northeast may still be in place. If the block holds, snow could be avoided in Detroit, Scranton and New York City.  Meaning that Pittsburgh, Philadelphia, Wilmington, Baltimore and New York City may be on the “bubble” for this snowstorm right out of the box.

“The storm is forecast to be over the Rockies and Intermountain West Wednesday, the Plains Thursday, the Midwest Friday, and along the mid-Atlantic coast on Christmas Day. For portions of the Ohio Valley and central and southern Appalachians, this could transpire to deliver an old-fashioned classic Christmas Eve snowfall.”

And here’s Foot’s Forecast’s Forecaster Ryan: “The stage is beginning to be set folks. The chips are beginning to fall more and more, and the likelihood of a Christmas snowstorm is getting higher with each passing day (as I said on MPT last night.) The things we can tell at the moment are that it is highly likely that Baltimore will receive some snow, and as for the potentially for a significant storm (4″+), odds are around 60%.

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