Jan 17, 2011: Snow And Ice Tomorrow

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


Today brought mostly sunny skies to the area in the morning, however cloud cover started increasing by the afternoon ahead of a low pressure that is currently bringing snow and sleet to the central Mid Atlantic. This storm will continue to spread northwards, bringing a wintry mix to the area tonight into tomorrow. This is not the end of the snow potentials, however, as by the late week yet another storm threatens to bring a significant snowstorm to parts of the region, potentially including parts of the NYC area.

Tonight Into Tomorrow: Snow/Sleet To Rain/Freezing Rain

We are currently seeing a widespread area of heavy precipitation in the eastern Mid Atlantic, spreading northwards into the exiting cold air mass. A cold air damming scenario is setting up, where despite the lack of cold air, the area will start out as snow, then change over to rain in the central and eastern parts of the area with freezing rain further inland.

Forecast For The Area: In Long Island, the storm will only bring a brief light snowfall, as the storm will quickly warm things up, changing the coast over to rain by the morning with up to 1 inch of snow expected. Further west though, into New York City, NE NJ and southern Connecticut, the snow is expected to last a little longer, with a wintry mix in the morning hours followed by rain in the late morning into the afternoon. At least 1 to 3 inches of snow are expected, with up to 0.1 inch of freezing rain north and west of NYC.

For the western parts of the area, the storm will start out as snow, which will become moderate at times, bringing a total of 3 to 5 inches of snow. By the late morning, a wintry mix is expected to fall, but as the temperatures may never get above freezing near the surface in some locations, parts of the area will continue to see freezing rain into the afternoon hours, leading to significant ice accumulations between 0.2 and 0.4 inch possible.

This has the potential to be a dangerous ice storm for the western parts of the area. There will not be an update posted tomorrow morning, instead the next update will be posted tomorrow afternoon.

Late Week Storm: Big Storm Potential

Yesterday’s models and even some of today’s models continued to show the potential for a weak storm on Friday affecting the area with light snow, however today’s runs took a turn to the other solution, now showing a big storm affecting the region. The GGEM and NAM models are the most extreme with this, with the NAM showing what would likely be a mix/rain event for the area, and the GGEM showing a heavy snow event with mixing for the central and eastern parts of the area. While it is still too early to determine which one is the most likely, both of these solutions cannot be ruled out at this time.

So far this winter, when we had potentials for big storms, most of the times they ended up verifying, and with the trends we are currently seeing with the models, it appears that this storm may not be an exception to that trend. On Thursday, we are looking at widespread snow from Oklahoma/Missouri into the Ohio Valley associated with a low pressure in the South, however the timing of the storm’s phasing will make the difference between a moderate snow event mostly to the south/east of NYC, to a significant/major storm for the area into New England, to a major snowstorm for interior areas with a wintry mix for the area.

The earlier that this storm phases, the more likely it is to be stronger early on and track further west, bringing more of a mix for the area, and the later the storm phases, the more likely it is to produce a significant snowstorm for the area. At this time, the 00z NAM has an early phase, and ends up taking the storm through the central Mid Atlantic, bringing a wintry mix for the area and rain further south. This is the westernmost scenario at this time. The GGEM model has phasing taking place a little later, bringing a major snowstorm for the area into New England. The GFS right now is more progressive and has a later phase, however it has been trending closer to a big storm with each run, and it is possible that it could continue with this trend through tomorrow.

Based on the set up, it does appear that at least some snow will fall across the region, and at this time I went with a 70% chance of precipitation in the area. If there are no major changes, I will likely raise this to a 100% chance with tomorrow’s update. At this time, I put snow in the 5-Day Forecast for the western/central parts of the area with a rain/snow mix further east, however this is subject to change, and it is possible that this storm could bring a rain/snow mix to most of the area, it could mainly stay to the south and east of the area with some light to moderate snow, or it could be a significant snow producer for the area. Stay tuned for more information on this storm and how it may affect the area.

Longer Range: Arctic Air Blast Moves In

The arctic air blast I have been tracking since early January remains on track for next weekend, as a very cold arctic air mass will follow behind the storm, then drop southeast to affect the region during the weekend. There is still some uncertainty on exactly how cold it gets, but the potential is there for low temperatures in the single digits for the area away from the coast with sub-zero lows inland for Saturday night, with high temperatures on Sunday potentially staying below 20 degrees for parts of, if not most of the area if the colder case scenario verifies. Stay tuned for more information on this time frame.

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