Feb 20, 2011 Brief Updates

Throughout the day today, I will post a few brief updates on the coming storms for tonight and Monday night, discussing the latest expectations and any potential changes in the forecast. The final storm forecast along with snow and scenario maps will be posted tonight.

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10 PM: Lowering Snow Forecast

Since this afternoon, there have been changes in the outlook for this storm. Looking at the radar, the storm is drier than expected, and there is also difficulty for the snow to move into the area as there is dry air in place, resulting in virga, or snow that is not reaching the ground. With the latest model guidance and the observations, here is the final outlook for the storm:

– Southeastern Connecticut will see the least snow in the area, with 1 to 3 inches of snow expected.
– A general 2 to 4 inches of snow are expected in most of the area, with the highest amounts towards western New Jersey with 3 to 6 inches of snow expected.
– Precipitation type will stay as snow for the entire area, as the storm will likely stay cold enough for snow to fall except for a brief period of mixing at the end south of NYC.

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6 PM: Snow Warning, Heavy Snow Watch In Effect

With the rest of this afternoon’s models, the trend has been colder and snowier, with most of them now taking the heavy snow axis through northern New Jersey and southeastern New York with the heaviest snow located in Orange and Sussex counties, where the potential for as much as locally 6 to 7.5 inches of snow exists. While some sleet may mix in with the snow in NYC, the main precipitation type should be snow, with plain snow expected north of NYC.

The latest expectation is for a widespread 3 to 5 inches across the area, with 4 to 7 inches further west/northwest and 1.5 to 3.5 inches for eastern Connecticut. The next update will be posted later tonight along with a snow map and a scenario map.

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12 PM: More Snow Possible?

Last night, I mentioned in my discussion that the colder and southern solutions for the first wave were becoming more likely, with a moderate snowfall north of NYC. This south trend continued, with most models this morning showing a widespread moderate snow covering the area with only a little mixing in the south central parts of the area, bringing a widespread 3 to 6 inches across the area with the highest amounts towards Orange county, NY.

While I think that mixing with sleet will affect most, if not all of northern New Jersey by the late morning as the storm starts to end, with rain also possible in the southern parts of the area, the worst of the storm should fall as snow, with the potential for 2 to 4 inches of snow in NYC and 3 to 5 inches further northwest/north/northeast. As a result, I upgraded the Snow Watch to a Snow Warning and extended it a little further south than yesterday’s Watch in northern New Jersey. There is still some slight uncertainty about the mixing issues and exactly how much snow falls, which will be sorted out later today and tonight.

The latest models have trended further north with the second wave, with some models such as the SREF and 12z NAM bringing nearly 0.25 inch of precipitation to NYC, which combined with temperatures in the 10s, would make this a high ratio snowfall with perhaps 2 to 4 inches of snow. At this time, I am thinking that this solution is too far north, and while I will watch it as the day goes on in case it becomes a new trend, I am currently expecting some light snow across most of the area, with up to 1 inch for the southern parts of the area. Stay tuned for more information on the second wave and how it may affect the area, if it does.

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