Turning Colder with Some Flurries & Windy Conditions for Wednesday. Mixed Precip & Wet Snow Possible On Friday with Coastal Storm.

Discussion: Tuesday AM 12/30/08
For The Delaware Valley.
Some Updated thoughts for Wednesday into Saturday.

Some interesting weather is coming up for the Delaware Valley over the next few days. The first system of interest is a fast moving Clipper system for Wednesday. The main effects will be a turn to sharply colder temps, and strong winds for Wednesday afternoon and night. This Clipper system will pass just to our north, and track across PA during Wednesday morning, and quickly move to the Southeast New England coast by early Wednesday Evening.

Much of the snow showers activity, and accumulating snow associated with this Clipper, will pass to our north from Northern PA, The Pocono's, into NW NJ, and then into New England. A general 1" to 3" of snow will fall in these areas, but 3" to 5" is possible over parts of SE NE into the Boston MA area. For Northern NJ into NYC and L.I. a general Coating to 1" can be expected for Wednesday.

For The Delaware Valley: Some flurries/Sprinkles are Possible Wednesday AM into the afternoon for The PHL area, and parts of Southern NJ. No accumulation, just some Flurry activity.

For Areas North and East of PHL: Flurries and Snow showers are more likely over "The Lehigh Valley" and Central NJ. A few spots in these locations could see a Coating to 1" with any heavier snow shower activity. Once again the Pocono's and NW NJ could see 1" to 3"

For the entire Delaware Valley Region: Winds will increase to 15-25 MPH and some gusts to near 40 MPH are likely during the afternoon and into Wednesday Night. Temps will drop through the 30's during the afternoon and we could see some Upper Teens and low 20's late at night.

For Thursday (New Year's Day) we can expect Cold and Breezy conditions with Mostly Sunny Skies. Highs will be in the Mid to Upper 30's. Clear and Very Cold at night with lows in the Upper teens to mid 20's.

Now comes the tricky part and tough forecasting for Friday into Friday night. This is really about the timing of two separate systems, and the location of some Upper level energy moving into the M/A and Northeast at about the same time. Let me sum this up to you guys in a nut shell, It's a hit or miss, all or nothing situation for our region. We could be looking at only some flurries & snow showers, or possibly several inches of wet snow from a coastal storm developing. Let's breakdown this scenario.

Thursday Night into Early Friday:

A Clipper system will be moving across the Upper Midwest and Great Lakes regions. Much Colder air, and some snow will accompany this Clipper for the Midwest and G/L's as it moves eastward. This is Feature # 1.

An Upper level trough and H5 (500mb) vort energy, will also barrel east across the Midwest during the same time. This feature will provide the energy necessary to spark a coastal storm on Friday and Friday Night. Also notice a developed 50/50 Newfoundland low in place, this is also a good sign for coastal development. This is Feature # 2

Now I'll talk about the coastal Storm, which is feature # 3. This is where things become very tricky in forecasting and timing is everything. A coastal storm could develop, just off the M/A coast and meet up and consolidate with the Clipper System off the new England coast, later Friday and Friday night.

If the coastal storm develops quick enough and phases just off the M/A coast, then areas of DE and NJ could see some accumulating snow during Friday and into the early evening hours. Temperatures during this part of the day will be critical as well. A mix of snow, sleet, and rain, changing to snow is the most likely chance here. At this time I'm going with a threat for some light accumulations over SE PA, Northern DE, and much of South and Central NJ with this event.

The QPF for Friday's event showing the heaviest precip over DE and NJ.
Here's where .10" to .25" amounts are possible. A 1" to 2" event is Possible over Southern and Central NJ.

Please check back on Thursday for my final thoughts on this possible snow event.

At this time I'm going with a chance of rain and snow showers for Friday and possible periods of snow in the afternoon and early evening, for Northern DE into PHL and much of NJ. Some light accumulations are possible over SE PA, NJ, and Northern DE. Highs in the mid to upper 30's. Friday evening, some flurries and snow showers, windy and turning much colder with lows near 20.

Take Care, Ruggie