Dec 19: Christmas Storm Potential

Reminder: The poll for the scenarios for the storm on December 24-26 remains open. Please vote your thoughts in the poll, which will close on Thursday.

The 5-Day Forecast was not updated tonight, but the forecast remains the same through Thursday.


Today was a mainly cloudy day across the area as a coastal storm that yesterday affected the Southeast stayed mainly offshore, but brought some light snow to parts of eastern Long Island. The storm is now moving into southeastern New England, bringing rain and snow to Cape Cod. Several days ago, the models showed the potential of this producing a snowstorm for the area, however there were several problems with this potential, which led to the storm being too far east for any snow to fall in NYC.

This coming week will bring generally steady temperatures in the 30s, with a few lower 40s on Wednesday, however another storm will then affect the region on Saturday, which needs to be kept an eye on as it may affect the area.

Tomorrow’s Outlook:

Tomorrow will bring clearing skies to the area with a breezy NW to NNW wind. High temperatures will be in the upper 20s to lower 30s inland, lower to mid 30s in the immediate NYC area, and in the mid to upper 30s for Long Island and southern Connecticut. A few readings above 35 degrees are possible in the warmer parts of the NYC area.

Tuesday – Thursday: Warming Up A Little

On Tuesday, the storm will continue to stay in the western Atlantic, meanwhile a weak low pressure will move ESE from the Midwest into the Great Lakes and towards the Mid Atlantic region, producing moderate to heavy snowfall into the Great Lakes. The clipper, however, will be unable to easily make it east of the Appalachians, and as a result the precipitation will significantly weaken, with only scattered rain showers making it east of the Appalachians as what’s left of the storm becomes absorbed into the larger storm offshore. As a result, scattered rain and snow showers are expected in the central Mid Atlantic, in places such as Washington DC, with perhaps some rain/snow showers affecting the area.

The cold air mass will temporarily weaken on Tuesday before another cold air mass will enter the region by Thursday, leading to slightly warmer temperatures, potentially reaching the lower 40s in the warmer spots in NYC and the eastern parts of the area on Wednesday. In terms of precipitation, I went with mostly cloudy skies with an isolated drizzle or flurry possible in the 5-day forecast, as any precipitation should be isolated and light. Note that the 5-day forecast was not updated tonight, but the forecast hasn’t changed for this time frame.

Thursday will bring colder temperatures to the area once again as another cold air mass returns into the region, but the attention then turns to the western United States, where a piece of energy entering California on Wednesday will start to move west to east through the United States, heading towards the area.

Friday – Sunday: Christmas Storm Potential – Mix, Snow Or Nothing?

Over the last 2 days, the potential for a storm to affect the area on Christmas Day has been mentioned as the models started showing a nor’easter affecting the area with near or over a foot of snow, especially on the GFS model. The ECMWF model has caught on to the GFS today, and while it was further east with the snow than the GFS, the exact precipitation area doesn’t matter considering this is almost a week out, and the model spread is unusually small with greater than normal consistency considering this is in the hour 144-168 range. There are still some models showing other solutions, such as the GGEM keeping snow to the south of NYC, and the 18z GFS is further west of the storm, bringing rain and some snow to the area, but normally in this time range there would be a bigger range.

At this time, the models are generally in agreement with showing a piece of energy moving into California on Wednesday, which will bring another round of heavy rain/snow there before a break in the precipitation takes place for 2-3 days. By Thursday, the storm should be located near Arkansas/Missouri, however where it goes from there is a question. It is possible that the storm intensifies early and moves NE further west, leading to the 3rd scenario shown above and rain/mix for the area. The central solution, the one that the ECM/GFS are favoring, would bring a large snowstorm, if not a blizzard to parts of the area, and the southern solution, supported by the NOGAPS/GGEM/UKMET models would keep snow to the south of the area.

At this time, the western solution is not too likely, and it seems to be either that the storm brings snow to the area or it’s too far south/east, but there is still time left until the storm’s energy moves inland, which is when the models will likely start to get a better idea of the scenario. Stay tuned for more details on this storm and how it may affect the area.

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