Stormtalk

Friday,  26 February:  2:00 p.m. EST

Broken record!

NYC (Central Park) set an all time monthly snowfall record at noon today with 35.9 inches of snow this month.  This breaks the all time record for total snow in one month in Central Park set back in March of 1896 when 30.5 inches of snow fell that month.

Link to source:
http://forecast.weather.gov/product.php?site=NWS&issuedby=NYC&product=RER

I don’t think the snow is over for the season – not yet.  We are in a stormy weather pattern and computer models are showing yet another potentially big snowstorm for the Mid Atlantic/Northeast coast on Wednesday.   It’s the winter that won’t end!  I would say Spring is just around the corner, but then I’d just be messing your heads.  The never ending winter continues…..

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Friday, 26 February :  9 a.m. EST.

I knew there would be a dramatic difference in snow accumulation from NYC into southwestern Connecticut, but this is impressive.  Central Park measured 16.9 inches of snow at 7 a.m. this morning!  Areas further north across the lower Hudson Vally of New York have around two feet of snow!  Contrast those totals with the 1 inch measured at Bridgeport, CT at 7 a.m.  What a dramatic difference 40 miles has made.

But now the snow is coming down in earnest across southern/western Connecticut – finally.  The upper level low is nearly stationary for now and producing moderate snow across southwestern CT where very little snow fell earlier this morning.

Below is the radar loop from 8:45 a.m. EST.  Notice how the snow band has set itself up over western CT just north of the area of low pressure.  As long as the low doesn’t retrograde during the day, southwestern CT may actually end up getting 3-5 inches of snow from this despite being robbed from all the snow overnight.

Below is the latest National Weather Service snow forecast for the tri-state region through Saturday morning.  They are actually pretty bullish, forecasting 6-8 inches of snow across western and southern CT.  Of course eastern NY has pretty much already made their mark with 16-25 inches on ground.

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Thursday, February 25:  1:45 pm

Above is the surface chart for 1:33pm EST.  Notice how all the cold air is near and west/north of NYC.  Once you get too far east of NYC temperatures rise into the upper 30s and lower 40s.  This presents problems because even when the strong dynamic lift moves in this evening and tonight and cools temperatures, it’s going to take much longer to get temperatures close to freezing over southwestern/southern CT vs.  NYC.  Basically, there is going to be a dramatic decrease in snow accumulation from west to east starting near NYC or extreme southwestern CT.  Bridgeport/New Haven will be on the line between a few inches of snow and nothing.  What a tough call.  Not to mention that all this snow will be wet with slushy accumulations and melting rates under the snowpack.

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Thursday, February 25: 9:15 a.m.

Well I’ve been putting off talking about this setup.  Most of the delay is due to me just not having as much enthusiasm for snow right now.  We are in late winter and I’m looking forward to the storm chasing season…so please bare with me as I gather the strength this morning to write an analysis on this rain/snow event.

For starters the heavy snow snow (12+ inches) will fall west and north of NYC.  This storm is going to be big for the interior areas of the Northeast, namely the lower Hudson Valley up to Syracuse and upstate New York.  Today heavy rain will fall over most of New England, with a rain/snow line pretty much right over NYC, and heavy snow west and north of NYC.

By this evening (Thursday evening) the intense low pressure system off the coast of New England will track westward as the upper level low retrogrades.  This will bring intense large scale lift over southern New England/NYC region and cool the entire temperature profile.  This will result in rain changing to wet snow from west to east from the NYC region over to southern Connecticut tonight.  What makes this setup so bizarre is temperatures at the surface will be just above freezing, while temperatures above the surface will rapidly cool to well below freezing as the night wears on and the storm system raps up.  The end result will be heavy very wet snow late tonight/early tomorrow morning over the NYC region/southern CT.

I’m going with 4-8 inches of wet snow accumulation by late Friday morning in the NYC to Stamford/Fairfield areas.  My place in Shelton will probably be in that range too, but I’m worried I may be a bit too far east to be in the upper end of  the range.  If I had to pick a number I’d go with 5 for my place.

But this is an especially difficult and strange setup to forecast.  The ground is not cold and will remain above freezing throughout this entire event from NYC eastward.  The surface temperature will also likely remain just above freezing. So we have a situation where very wet snow will fall like mad for hours on top of a ground that’s above freezing.  So we have to take into account 1)wet snow has a lower ratio than dry snow, keeping snowfall totals down and more importantly 2) there will be a melting rate at the base of the snowpack throughout the event.

So while even if the WRF model is correct in forecasting 1.2 of liquid equivalent precipitation, and normally that would bring about a foot of snow, we can’t use that kind of calculation/interpretation with this setup.

As always I’ll take my five inches of snow and enjoy it.  Spring is just around the corner…..

- Jim