Monday storm: 4-5 inches. Or 6 inches. Or 12...?
This much seems unavoidable: The Alberta Clipper steaming across the Plains will bring the mid-Atlantic states more snow on Monday into Tuesday. What remains unclear more than two days out is just how much we should expect from the fourth winter storm of the month.
UPDATE: The NWS now seems to be predicting a more northerly track for the storm. That would mean less snow for Baltimore, but more rain instead. And with all this snow still lingering on rooftops, and waiting to melt, more rain means more weight and a faster melt. Neither is good news.
If there is any good news, it is that we were spared more snow and misery from the Dixie snowstorm that has been tangling traffic and delighting kids across the Deep South in the last day or two. That one headed due east and failed to make the familiar left turn up the coast that so often brings us snow or wintry mixes in a season like this one. Small favors. At least these folks in Macon, Ga. enjoyed it.
The Clipper, however, seems destined to cross our path. The only good thing about it is that these storms are much drier than the Gulf Coast storms that throw so much Gulf and Atlantic moisture our way.
The chief worry is that, once it reaches the Atlantic, this Clipper will intensify and draw both energy and moisture from the Atlantic, sweeping that back in our direction, producing snow on the high end of today's estimates, rather than on the low end. With luck, the timing of that intensification will allow the worst of the storm to be visited on New England, and not us. We've had plenty of snow already, thank you very much. Let's share the wealth.
So here's the deal so far:
The National Weather Service is not predicting accumulations. It's too soon for them. But, in this morning's Forecast Discussion, the folks at Sterling are dropping some hints:
"AS WITH MOST CLIPPER LOWS...THIS SYSTEM WILL NOT HAVE A LOT
OF MOISTURE TO WORK WITH UNTIL IT TAPS INTO ATLANTIC MOISTURE AS IT
APPROACHES THE COAST. ALTHOUGH IT IS TOO FAR OUT TO FORECAST EXACT
SNOWFALL AMOUNTS...HIGH SNOW TO LIQUID RATIOS AND STRONG UPPER-LEVEL
DYNAMICS COULD BRING THE POTENTIAL FOR A HIGH-END ADVISORY OR
BORDERLINE WATCH/WARNING FOR PORTIONS OF THE AREA...ESPECIALLY WEST OF
THE BLUE RIDGE AND ACROSS NORTHERN MD. MIXING ACROSS LOWER SOUTHERN MD AND NORTHERN PIEDMONT IN CENTRAL VA COULD LIMIT SNOWFALL ACCUMULATIONS."
The hidden clue here is "high-end advisory or borderline watch/warning." That would translate into 4 or 5 inches of accumulation, since the NWS would issue a Winter Weather Advisory up to 4 inches, and a Winter Storm Watch with a forecast of 5 inches or more.
Okay. On to the other prognosticators. AccuWeather.com says we're in the crosshairs once again:
"Hard-hit Washington, D.C., Baltimore and Philadelphia have the potential to receive around half a foot of snow from this storm. New York City is also likely to get in on some of the heavier snow."
And here's Mr. Foot and his student forecasters:
"Our original analyses first published Thursday 2.11.2010 remain on track: 6 inches or more by Tuesday noon across much of the I-95 corridor from Washington to Philadelphia. Amounts may approach 12 inches in portions of northern Maryland, as well as the MD eastern shore and Delaware. The snow will arrive on radar by noon Monday, but due to cold surface and upper level temperatures, may not reach the ground until late afternoon. Honesty, we wish there were better news to warm your heart on this Valentine's weekend."
And finally, here is Eric the Red, a professional meteorologist from Baltimore:
"As it stands now, I think we should hold the line of a chance of snow Monday afternoon and Monday night, with a best guess of 3-6"... with locally more to the north of the low center. I am beginning to think this may be a bit high, but I've always preached (and tried to practice; sorta) sticking with your gut. If the low tracks farther north, then we would get much less (1-3" maybe), and if the low passes too far south we'd be left high and dry. Again, with a much smaller (but still strong) system, the room for error is much less."