Feb 24, 2012 Storm Updates

11:40 AM: Reviewing Last Night; Strong Winds Tonight


Following what was perhaps the most difficult forecast of the year due to a lack of consistency in the short range, the storm last night did end up producing a last minute snow/sleet accumulation for parts of the area as expected last night; the original expectation from most of the models as of Wednesday night for last night was still for rain with perhaps light snow/sleet mixing inland. The changes made yesterday did end up generally accurate in terms of the accumulation amounts, as a narrow zone did report 1-3 to locally 4 inch accumulations, but that band ended up not too far south of last night’s map; Sussex county to SE New York, into coastal southern Connecticut and further inland observed widespread 2-4 inch amounts last night, with light snow/sleet making it towards the I-80 corridor in NJ and parts of NYC and Long Island; one town in Suffolk county even reported half of an inch of snow/sleet. My forecast from last night was not completely accurate, and it would’ve also been very difficult to make a spot on forecast given all of the lack of agreement from the models in the short range and the dependence on the radar and other short range forecasting tools, but considering all of the uncertainty, the forecast was not completely off, as the zones ended up approximately 30 miles or so south of where I had them in my map last night.

Either late this weekend or sometime next week, I plan to post a review of the forecasting for this storm, along with its impacts in the area. The model guidance did not have a good handle on the storm, even in the short range, and only 12-24 hours before the storm places that were modeled to have the most amount of snow, from east central New York into Massachusetts, barely had any snow as most of it stayed to their south. In fact, just 3 days before the storm the potential was there for temperatures to reach 55-60 degrees in parts of the area. That boundary of temperatures is now well to the south of the area, and temperatures are expected to struggle reaching 40 degrees today, failing to pass that mark in parts of the area.

Forecast For Tonight: The southern Mid Atlantic is currently under a Moderate Risk of severe weather by the SPC (Storm Prediction Center), an appearance that is not common during the winter months, especially in this part of the United States. With the temperature boundary well to the south of the area, temperatures will surge into the upper 70s and even 80 degrees in parts of Virginia today as severe thunderstorms begin to form and intensify later this afternoon. Severe weather parameters are favorable for severe activity and perhaps some tornadoes, with LI down to -5/-6, CAPE up to 1250, and bulk shear up to 60-70 knots. A secondary low pressure should form along the warm front later today when the severe thunderstorms form in the Mid Atlantic, and begin to move up the coast as it intensifies and becomes the main low pressure. As the low moves up the coast, the storms from the Mid Atlantic will become more widespread, forming a larger area of rain along with the coastal low. Some of the storms in the Mid Atlantic, although non severe, should reach New Jersey later today, and parts of the area may see briefly heavy rain this evening. The rain will then move to the north/east of the area by tonight with clearing skies expected.

The biggest concern for the area, however, is the winds from the storm. Although the warm front will not cross the area, there is a tight pressure gradient setting up just behind the storm, and the models are showing a strong signal for strong wind gusts today, stronger than the rest of the wind events of the season so far. While it will not be very windy all the time, the potential is there for widespread gusts in the 45-55 mph range across the area tonight as the coastal low exits, with gusts perhaps up to 60 mph, locally above 60 mph, in parts of Long Island and southern Connecticut. In an update I will make to the Weather Alerts page shortly, I will also issue a High Wind Watch for the eastern half of the area, which may be upgraded to a warning later today depending on any changes in the storm. Windy conditions will continue tonight with gusts still reaching the 40 mph range at times, with windy conditions returning again tomorrow with winds gusting again up to 45-50 mph, locally up to 55-60 mph especially towards Long Island.

The next update will be posted on Saturday, 2/25, with an update on the rain storm and possible warmth for late next week.

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