Snow on the horizon?

Sorry for the lack of posts over the past week or two, but since the weather took a big break after Sandy and the fluke snowstorm, I needed time to catch up on work. Here we are after Thanksgiving and outside of some nuisance cold fronts, the weather has been amazingly beautiful. Well. . .all good things come to an end and that will start tomorrow. Another cold front (the last in this series of colder outbreaks) will slip through the area tomorrow with a wave of low pressure forming on the front by late day. This wave will bring some rain, possibly changing to snow from areas north and west of DC through the Poconos and Catskills. Could it snow farther east? Yes, but this will become a nowcast issue as the precipitation will be falling during the day and the storm will be weak, therefore not enough cold air will get drawn into the system before the precipitation ends.

Snowfall forecast from the Mt. Holly, NJ National Weather Service office.

The map above shows the Mt. Holly NWS snowfall forecast for tomorrow. As you can see, most of the coastal areas of NJ should see little to nothing this time, while farther inland amounts could top out around 4″. If the cold air is deeper than currently forecasted, then snow may be the dominant precipitation, but things like this can be tricky to forecast correctly. My best guess for NJ is rain changing to snow with light amounts inland similar to the map above, but the coastal areas could pick up 1/2″-1″ tops if the cold air wins out by evening.

Snowfall forecast from the Baltimore/Washington National Weather Service.

The snowfall forecast from the Baltimore/Washington NWS above shows no snow accumulation in the 95 corridor, but some light amounts are possible north and west, especially near the MD/PA border. Now, this is where I think the forecast could be too light as I see how the cold air could get into the metro area in time to turn the rain over to snow with a light accumulation. As of now, I think it’s possible we could see up to 1″, especially near I-95, but this is a low-confidence forecast. The storm will be strengthening (slightly) as it passes the area which could draw in the cold air fast enough by evening. I could be off here, but the signal in the models has been consistent and it gets dark earlier now, so this is something to watch as it unfolds during the day.

18z NAM model snowfall forecast valid at 7 pm EST on 11/27/12.

The latest (18z) NAM snowfall forecast above shows the cutoff line for snow just north of Baltimore, but almost to the coast of NJ with higher amounts near and north-northwest of Philadelphia. This seems reasonable, but my worry is that it might be a bit too far north.

Tough forecast even with the event starting in the next 12 hours. This is what keeps me so interested in the weather. Thanks for reading!

Forecast confidence: low

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