Tuesday, November 13, 2007

A Very Active Pattern continues into early next week. Colder Air returns with a Coastal Storm threat for Mon/Tues.

Discussion and Forecast:
The Delaware Valley and M/A Region.

Let me start by saying we're entering into a phase of this pattern, that will offer a more stormy outcome, as we head into next week. Temps for the most part have been below normal for much of this month, as the Northern Branch has finally entered the picture. This will continue into next week, as another Strong Cold Front crosses the region Early Thursday, bringing a return to Below normal temps.

Skies will become Cloudy on Wednesday, as a SW flow of Milder air moves in ahead of this front. Temperatures on Wednesday will reach the low to mid 60's, Across much of the Delaware Valley. Showers will work there way in for Wednesday Evening, followed by a period of steady Rain and even a thunderstorm in a few locations, for later Wednesday Night into Thursday morning. I'm forecasting .25" to .75" Rainfall amounts with this frontal system. A few locations near any convective bands, could exceed 1.00".

On Thursday the Cold front crosses the area, and clears the coast by afternoon, A strong NW flow and CAA will follow for Thursday afternoon and continue into Friday. This will drop our temperature back to the low to mid 50's for Thursday and Upper 40's to lower 50's for Friday. Skies will be Partly to Mostly cloudy, along with a few scattered rain and or snow showers for Thursday Night and Friday morning. Temperatures will be in the mid 30's for Thursday Night.

The weekend looks to be breezy and Cold with mainly P.Cloudy skies both Saturday and Sunday. A weak disturbance could cause a few showers of rain or wet snow Saturday night, but these will be light and widely scattered. Highs both days will be in the mid 40's to near 50, and lows in the lower to mid 30's.

There are some indications now, that a coastal low will develop Monday night into Tuesday of next week, as another H5 low and trough move into the M/A and NE. This trough is progged to become NEG TILTED along the M/A Coast, and develop a rather strong surface Low near the Carolina's Monday Night. At the same time a very strong Cold High Pressure system will be setting up over SE Canada. This has the potential to funnel in enough cold air (CAD) that some frozen precipitation is possible on the NW fringe of this coastal storm.

The I-95 corridor from DCA to NYC could see there first Snow/Sleet event of the season, but I do expect rain and marginal temperatures to also be a big factor during this potential event for early next week. At this time I'd say it needs to be watched closely over the next few days, but trends over the past day or two, continue to show this threat on the models. I'll leave at that for now, with a more detailed forecast and call, this weekend. Key here is, this looks like our first real potential for wintry precipitation. Our best timing and hope for some snow and sleet, is for this event to occur Monday night into Tuesday morning, and the Coastal Low staying 200 to 350 miles offshore. The Big High in SE Canada must be in place as the models are showing, or IMO it's game over, for potential Snow or Ice along I-95 Corridor !

Take Care,

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