Jan 16, 2011: Forecast For Tuesday’s Storm


***This post is from 2011. Please visit the MAIN PAGE to see the latest forecasts for January 2012.

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Today brought mostly to partly sunny skies to the area with high temperatures generally in the lower to mid 30s across the area. A cold air mass is currently over the area, which will lead to a brief yet intense cold spell, with what may be the coldest night of the winter tonight. Tomorrow will be a very cold day, with high temperatures struggling into the 20s, however another storm that will move in will bring a wintry mix for the area on Tuesday, with potentially significant amounts of freezing rain inland.

Tonight’s Forecast: With mostly clear skies tonight and a high pressure nearby, temperatures will steadily drop tonight, reaching their coldest point yet in most of the area. Low temperatures are expected to be between -5 and 4 degrees inland, in the lower to upper 0s for the north/west suburbs of NYC and southern Connecticut, mid 0s to lower 10s for Long Island, and lower to mid 10s in NYC.

Tomorrow’s Outlook:

As the high pressure will be near the area, a generally light and variable wind is expected. The cold air mass will still be in place, leading to high temperatures being at their coldest so far this winter, in the upper 10s to lower 20s inland and in the lower to mid 20s for the rest of the area.

Note that the interior areas, the warmer spots near/south of NYC and parts of Long Island may be slightly warmer than the map is showing.

Monday Night – Tuesday: Wintry Mix To Rain

A coastal low that will start to take shape late tomorrow off the Southeast coast will affect the area by the overnight hours. Most of the models seem to be in general agreement with the storm track with some minor differences, however it does appear that at least some snow falls over most of the area, with a cold air damming scenario leading to freezing rain further inland. The NAM was an outlier today, showing a much further east and weaker solution with barely 0.25″ QPF in NYC, however it seems to have corrected itself in its latest 00z run and trended wetter, a little faster, stronger and colder at the same time. While its solution may be a bit too extreme, it also highlights the potential for snow to accumulate in the start of the storm, with more significant freezing rain inland.

Forecast for the area: Light snow is expected to begin across most of the area around 12 AM, a little later in places further north/east, and will quickly change over to rain near the coast by the morning with less than 1/2 inch of snow expected. The rain may be heavy at times, with 1 to 1.5 inch of rain expected.

In the immediate NYC area, snow will likely persist until the morning hours, when a brief period of freezing rain is expected before changing over to rain. Snow accumulations up to or near 1 inch are expected for NYC, with near 1-2 inches and less than 0.1 inch of freezing rain in the north/west suburbs. The rain may also be heavy at times in the afternoon and evening, with rain totals between 0.75 and 1.25 inch possible.

Towards western Bergen, western Passaic, Rockland, Morris counties and further northwest, however, it will be a different story. The snow may become moderate at times by the morning, with at least 2 to 4 inches of snow expected. 850 mb temperatures will rise above freezing, however the cold will remain trapped near the surface, resulting in freezing rain becoming the main precipitation type by the late morning. Parts of the interior areas will change over to rain, however it is possible that parts of the interior areas may continue to see freezing rain with no changeover to rain. As a result, I issued a Freezing Rain Alert for the interior parts of the area, highlighting the potential for freezing rain amounts to reach 0.25 inch.

My preliminary scenario map for this storm was posted in the top left. There is still some slight uncertainty with the storm, and it is possible that slight changes could be made by the time that the final discussion and map will be posted tomorrow night, including potentially raising the expected snow amounts further inland. Stay tuned for more updates on this storm tomorrow.

Longer Range: Uncertainty Increases

Behind the storm, except for Wednesday which will bring even warmer temperatures into the lower 40 for parts of the area, it is expected to get colder again, with high temperatures once again returning into the 20s by Thursday, however there is more uncertainty for Friday regarding a storm that may affect the region. The ECMWF was the highlight of today’s models, twice showing a big snowstorm for the area around Sunday, but even though there is not much support for the ECMWF’s solution at this time, it will continue to be watched until there is better agreement with the models.

It appears that we will see a wave of low pressure on Friday, however what happens with it on Friday and afterwards is a question. Most of the models are suppressed with this, keeping most of the snow to the south of the area with only light snow in the immediate NYC area, however some solutions are further north, and the ECMWF have a different scenario, showing the main storm on Sunday, not Friday. There is still a lot of uncertainty at this time with this time frame, so stay tuned for more information on this potential storm over the next few days.

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