Jan 9, 2011: Discussion On Tues-Weds Storm

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



– The 5-Day Forecast was updated, but only through Thursday.

– Snow and Heavy Snow watches were issued for the appropriate parts of the area. Please refer to the “Weather Alerts” page for the latest alert in your area.

– A new poll has been opened in addition to the one that is currently active, about the potential snow amounts in NYC. The first poll has been extended through tomorrow afternoon, this new poll will close on Tuesday afternoon.


As the coastal low cleared the area this morning, mostly to partly sunny skies were observed today, with high temperatures in the upper 20s to lower 30s across the area with a few mid 30s. Currently, a large winter storm affecting the Southeast with widespread heavy snow and freezing rain, and this storm will start to move up the coast, bringing a major winter storm to the area.

Tuesday – Wednesday Storm Discussion: Major Winter Storm

Currently, a major winter storm is affecting the southern United States with widespread heavy snowfall and freezing rain. Meanwhile, there is also precipitation in the central United States. While the precipitation in the South will likely weaken tomorrow, we will see the storm move up the coast to bring a large snowstorm to the NYC area. The highlight of today’s model runs were the ECMWF and the 12z NAM, which brought over 10 inches of snow to parts of the area, and the 00z NAM which is currently running, also shows a huge snowstorm covering the central parts of the area. While some models are much lighter with the precipitation, it is possible that they may be underestimating the amount of precipitation that this storm brings to the area, therefore I am leaning with higher precipitation totals for my forecast.

Storm Set Up: As there are no significant changes with the expected set up, I used yesterday’s map to the left to show where the storm will track and when. I am leaning with track #2 but going slightly closer to the coast. We are still looking at a low pressure moving up the coast tomorrow through Tuesday with a primary low moving inland, both of them bringing light to moderate snowfall up to the central Mid Atlantic with mixing issues south of the Interstate 95 corridor.

From there, the coastal low pressure will take over as phasing takes place, and the storm will rapidly intensify off the New Jersey coast. This will lead to intensifying precipitation, with the heaviest precipitation potentially centered from the NYC area into southern New England. It appears that mixing with sleet and rain will be confined to eastern Long Island, however this can still change, and it is possible that there could be no mixing in the area, or the mixing could extend further west into New York City.

Thoughts For NYC Area: Light snow is expected to start for the area during the late afternoon or evening hours as the storm approaches from the south, gradually intensifying through the early overnight hours. The worst of the storm is expected to take place around early Wednesday morning, with potential impacts in the stronger storm scenario including snowfall rates potentially between 2 to 3 inches per hour, wind gusts near or potentially over 40 mph leading to near blizzard conditions at times, and thundersnow also cannot be ruled out if the stronger and snowier strm scenario verifies. The eastern parts of the area may see mixing with sleet and/or rain, however significant snowfall amounts are also expected there. The snow should start to weaken by the morning hours and will end by Wednesday afternoon.

At this time, there is the potential for at least 8 to 14 inches of snow for the immediate NYC area as well as western/central Long Island and southern Connecticut, but it is possible that I may have to lower or raise these amounts depending on the model trends and observations tomorrow. Note that there is still uncertainty on the exact storm track and where it intensifies, with possibilities including a further west track to bring more widespread mixing with sleet and rain south and east of NYC, a storm track further east that keeps the heaviest snowfall east of New York City, or the storm bringing more snow than currently expected, with the potential of up to 10-18 inches of snow in NYC in the most extreme scenario, shown by tonight’s 00z NAM run.

This has the potential to be a major snowstorm in the immediate NYC area, and should not be taken lightly. Stay tuned for more information on this storm over the next two days.

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