After temperatures spike well into the 60s, if not near 70 on Monday along the Mid-Atlantic and Northeast I-95 corridor, a significant cold front sweeps through on Tuesday. This front sets the stage for a possible coastal storm on the Wednesday before Thanksgiving, which could bring substantial rain and/or snow.

Wednesday’s possible storm – which has a chance to develop into a legitimate Nor’easter – would form along the cold front stalled off the Southeast coast. The exact track of the storm will determine whether its effects are significant or not.

We should stress uncertainty in the forecast is high, and forecast confidence is low.

Current model simulations suggest 3 possible scenarios:

1) The storm is more out to sea, with just a glancing blow for the East Coast Wednesday (Canadian model, GFS parallel model, and GFS ensemble mean) – Low impact



Canadian model forecast for 7 p.m. Wednesday (WeatherBell.com)

2) The storm moves up the coast just offshore, with snow for coastal areas and sharp cutoff to precipitation farther inland (GFS operational model, European ensemble mean) – Moderate impact



GFS model forecast for 7 p.m. Wednesday (WeatherBell.com)

3) The storm hugs the coast, with heavy coastal rain and strong winds, and heavy inland snow (European operational model) – High impact



European model simulation at 7 p.m. Wednesday night. Dark blue line is 32F line – near and west of which accumulating snow would be most likely. (StormVistaWxModels.com)

Scenarios 2 and, especially, 3 would pose major headaches for travelers on the busiest travel day of the year from Florida to New England. It is too soon to say which of these three scenarios is most likely.

Wes Junker, Capital Weather Gang’s winter weather expert, weighs in for some specifics with respect to Washington, D.C.’s forecast:

The models are converging towards a solution offering a developing storm along the North Carolina coast on Wednesday. Today’s GFS model has shifted west with its low position joining recent runs of the operational European model in spreading precipitation across the area Wednesday. About half the European model’s larger group of simulations also were predicting precipitation sometime on Wednesday or Wednesday night. Some indicate that there could be accumulating snow for Washington, D.C.’s western suburbs. If the storm track is perfect and precipitation heavy enough, even the immediate D.C. area could get accumulating snow. Surface temperatures on both the European and GFS are marginal for snow as they keep the temperatures above freezing during the bulk of the precipitation. It’s too early to make any real call about the storm as the surface temperature forecasts this far in advance of a storm are tricky. If you are going to be traveling Wednesday pay close attention to the forecasts over the next couple of days.

The storm should be a fast mover, quickly exiting the Mid-Atlantic Wednesday night, and New England by early Thanksgiving day.

You may see forecasts and maps for snow amounts flying around the internet, but it is way too early to speculate about specifics given the uncertainty in the storm track.

A second, much weaker, disturbance could swing through the Mid-Atlantic and Northeast on Thanksgiving itself with scattered snow showers and/or flurries.