Thursday, December 6, 2007

WEEKEND OUTLOOK: Unsettled and Continued Cold With Some Light Wintry Precip


A weak system now moving across the Ohio Valley this morning, will move east northeast and bring a period of Occ. Light snow and snowshowers mixed with Sleet and rain south of PHL, later this morning into this evening as a warm front moves through. Later tonight into Saturday morning some additional light wintry mix of sleet and Freezing rain, and some light rain will occur, as this system pushes offshore and it's associated cold front moves through. Later Saturday High pressure builds in to our north, allowing for some breaks in the clouds. This will be short lived, as more steady wintry precipitation and a cold rain, move in for Sunday and Sunday Night.

We're about experience a stretch of mainly cloudy weather with some bouts of wintry precipitation, and a cold rain, from Sunday into the middle of next week. A very complex and tricky forecasting period will be the rule from Sunday through Tuesday. A thermal boundary of very cold air and High Pressure will setup to our North and West. In addition a SE Ridge will produce a Southwest flow aloft, and set up much milder air to our south. This battle zone will likely setup shop over The Northern M/A States over the weekend, and continue into early next week. This spells a stalled out stationary front from near NJ/DE coast, through PA and into the lower Ohio Valley. Waves of low pressure will develop on this front, and move along the front, bringing some Snow, Sleet, Freezing Rain, and a cold rain to much of The Northern M/A States.

During the beginning of this period, for both Sunday and Monday, Strong High Pressure will be draped to our north, from the Great Lakes into Northern New England. Very cold air will be present with this High Pressure system, and areas north of this stationary front, will experience some Snow and Ice. This will likely be from The Northern Ohio Valley, into Northern PA, Northern NJ, and Southern NY State. Ice will be the primary concern as CAD and low level cold air are filtered in, and precipitation breaks out. Areas to the south of this region, will also have some wintry precip, Sunday into Monday, but mainly a cold Rain, from Southern PA into much of Central/Southern NJ and DE.

I'll have more on this setup during the weekend, probably Saturday with more details. This setup needs to be monitored very closely through this weekend and into early next week. Any slight shift south of this boundary, will cause big implications to the forecast, here in the Delaware Valley, as cold air and High Pressure will be close by to our north. Ice is my main concern, and threat for Sunday into Monday for the Lehigh Valley/NW NJ and Poconos regions.

For the Delaware Valley:

Mostly Cloudy and Cold with some Occ. Light Snow and snow shower developing this morning and continuing into early this evening. Precip mixed with Sleet and rain, South of PHL. Highs in the mid to Upper 30's. Little or no accumulation, mainly north of PHL.

M.Cloudy and cold with a light wintry mix late at night. Lows in the lower 30's.

Early morning wintry mix and light rain, then P.Cloudy in the afternoon. Highs in the low to mid 40's.

Cloudy and Cold with a wintry mix during the morning over all areas. Continued snow, sleet and Freezing rain, N and W of PHL during the afternoon. wintry mix or rain S & East. Highs in the low to mid 30's N & W, and Upper 30's S and E of PHL. Some Light snow and Ice Accumulations are possible, N & W of PHL.

A complete Forecast update, and discussion for later Saturday. More thoughts on The Ice threat and specifics of where it sets up, for Sunday into early next week.

Take Care,

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