Feb 27, 2011: Heavy Rain And Storms Tomorrow

After a weak storm this morning brought snow for the area north of New York City, with light accumulations in southern Connecticut and SE New York, temperatures quickly warmed up this afternoon, reaching the mid to upper 40s in the western parts of the area, upper 40s to mid 50s in the immediate NYC area, and lower to upper 40s in Long Island and southern Connecticut.

Cloud cover is increasing again tonight as a storm is moving into the region, producing two rounds of rain, one in the morning with rain and some thunder, then a second round with rain and thunderstorms, producing locally heavy rainfall and gusty winds, which may result in up to 1-2 inches of rain. There has been a trend, however, to put the area in a dry spot, keeping the heaviest rain and strongest storms both south and north of the area with only 1/2 inch of rain for NYC, being why a Rain Watch is in effect for the area due to moderate confidence of over 1 inch of rain. Drier conditions will return by Tuesday and last through the week with variable temperatures, though the dry conditions won’t last much longer as yet another storm will affect the region next weekend, also bringing the potential for heavy rainfall.

Tonight Into Tomorrow: Heavy Rain, Strong Thunderstorms

Yesterday, I mentioned how there was uncertainty with the models as the NAM and GFS brought the storm in two separate waves, which was a possibility that needed to be watched. The models trended back to their original idea, with rain in the morning, a break in the afternoon, then rain and thunderstorms in the evening. Below, I will discuss the storm’s impact on the area and the region, including the severe weather potential.

Tonight: A severe weather outbreak is currently taking place in Missouri and is moving towards Illinois, associated with a low pressure near Oklahoma that will move towards the region by tomorrow, reaching northwestern Pennsylvania by tomorrow morning. Precipitation will move in from west to east tonight, and while some freezing rain will start north of the area, the area should start out with plain rain.

Tomorrow: The first part of the storm will move through in the morning and will clear most of the area by noon. This part of the storm, however, appears to stay mostly to the north of the area with the heaviest rain towards the Northeast, though some rain and thunderstorms are expected in the morning.

By the afternoon, there may be some breaks in the clouds with mostly cloudy skies, and as the area will be in the warm sector of the storm, temperatures will be able to rise into the 50s for most of the area, and 60s from NYC and further south/southwest.

The second part of the storm will then move towards the area by the evening, and will bring the main risk of severe thunderstorms to the Mid Atlantic. It appears that the highest severe weather risk will focus from West Virginia to the Washington DC area and towards southern New Jersey, where the storms may produce gusty winds and heavy rain, locally up to 2-3 inches, resulting in a 30% risk of severe weather. While there is some uncertainty with the northern end of this strong squall line, the heaviest storms appear to stay to the south of New York City from this round.

If the area gets hit by at least one of the rounds tomorrow, especially the second one, rain totals could easily range from 1 to 2 inches across most of the area, but if the storm does end up missing the area, rain totals could range from 1/4 inch to 3/4 inch, being why I have a moderate confidence Rain Watch in effect for the area. Stay tuned for storm updates that will be posted tomorrow afternoon.

Longer Range: Tomorrow night’s update will discuss the longer range in more details, along with a brief return to colder weather for Thursday and another potential heavy rain event for Sunday, March 6.

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