Dec 4: Cold Week Ahead, Then Storm Potential

Today was a mostly cloudy day, and even some flurries were observed across parts of the area, with high temperatures in the mid 30s to lower 40s across the area.

The radar image to the left from 9 PM today shows dry conditions across most of the region except for light precipitation in SE Virginia and eastern North Carolina. This precipitation is falling in the form of a snow/rain mix, and even though the precipitation weakened through the afternoon, early in the afternoon these light rain/snow showers were an impressive early season clipper bringing a widespread area of moderate snowfall from the Ohio Valley into the Virginia/North Carolina border.

This clipper is now moving offshore, however it will not exit the picture, as it will return by Monday, striking Maine as a powerful 960 mb low pressure, bringing heavy snowfall for Maine, while setting up the pattern for the coming week.

Tomorrow’s Outlook:

**Note: There is a mistake with the high temperature label with the graphic below, it should say “33-39 degrees”.**

Tomorrow will be a partly cloudy day across the area, with colder temperatures expected. A NW wind is expected, with breezy conditions at times. High temperatures will be in the lower to mid 30s inland and in the mid to upper 30s for the rest of the area.

Low temperatures tomorrow night will be slightly warmer than those of tonight, but still cold, in the lower 20s inland, mid to upper 20s north and west of NYC and in Long Island/S CT, and in the lower 30s in NYC.

Monday – Thursday: Very Cold, Mainly Cloudy And Breezy

As previously mentioned, the clipper that brought light snowfall for the southern Mid Atlantic today will move offshore, then rapidly intensify while moving northwest towards Nova Scotia and Maine, hitting these areas as a 960 mb low pressure, the equivalent of a Category 2 hurricane. While the winds won’t be as strong, it will deliver heavy snowfall, some rain, and high winds to Maine on Monday, while it helps keep the cold air trapped over the East, leading to a large trough covering all of the eastern and central United States as shown in the scenario map yesterday.

This low pressure will be slow to leave, and as a result, will control the pattern through Wednesday. Monday and Tuesday are expected to have very similar conditions, with mostly cloudy skies, high temperatures in the lower to upper 30s, breezy conditions each day with winds gusting above 30 mph at times, and the potential of isolated snow showers.

On Wednesday, an arctic air mass stronger than the one present will move southeast out of Canada, but due to the pattern in place will be focused on the Northeast. While the core of this arctic air mass will be to the north of NYC, it will bring even colder conditions, and a high pressure moving in will allow for less cloud cover and less wind, therefore colder overnight temperatures. High temperatures for Wednesday and/or Thursday are expected to be in the upper 20s to mid 30s across the area, with low temperatures potentially as low as the mid 10s inland, upper 10s to lower 20s north and west of NYC and in S CT, lower to mid 20s in Long Island, and mid to upper 20s for NYC.

Friday – Sunday: Cold Relaxes, Clipper Brings Rain/Snow Potential

On Friday, after very cold morning temperatures, the cold air mass will begin to moderate as an Alberta Clipper approaches the Great Lakes, leading to slightly warmer temperatures returning to the area. There is still a lot of uncertainty with how this clipper behaves, ranging from a cold front on the ECMWF model to a snow band stalled over the immediate NYC area with 3-6 inches of snow on the GFS model, but as the cold will relax, the clipper will not be suppressed like today’s clipper was, and in fact may track north of the area, and due to the cold air in place, may lead to rain/snow affecting the area between Friday night and Sunday. More details on this potential will be posted over the next few days.

For the longer range, those who are following the long range of the GFS/ECMWF models have seen them showing another potential storm around Tuesday the 14th, followed by another arctic outbreak. The arctic air outbreak is a possibility, as the models have been in agreement and nicely consistent with showing another arctic air mass directed over the Great Lakes/Northeast by this time frame, but whether another storm is involved with this and how is still uncertain. Stay tuned for more details on this time frame.

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