Very Cold & Some Snow Possible this Weekend: A Hit or Miss setup with Coastal Storm For Sunday/Sunday Night.

Saturday AM Update:
730 AM

My low temp, bottomed out at: -1.7 F @ 7:15 AM

Bad news ! Looks like we are cooked again here ! The coastal storm will be too far offshore and I only expect some flurries on Sunday with the northern Clipper system. A complete miss with the coastal storm !

My Final Forecast will be issued later today !

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Discussion:
1/16/09 Friday AM
For The Delaware Valley

The Cold Weather Continues:
Well, Well, where do I start with a very complex situation for this weekend. One thing's for sure, the very Cold weather will continue through the weekend, and continue into the middle of next week, with Much Below and Below normal temps. The Bitter and most intense cold will be with us today and tomorrow with Partly Sunny Skies, as Highs remain in the mid to upper Teens today, and only in the low 20's on Saturday. For Tonight temps will tank to near zero in many suburbs, with single digits in PHL.

Now let's talk about our complex setup for later this weekend. Once again, the Delaware Valley is facing a very close call between 2 separate storms, A Clipper to our north and a coastal Storm. This puts us in a sandwich between two slices of bread. Will there be Peanut butter and Jelly, or some lunch meat between the slices of bread, is the question to be answered.

The Clipper:
I'll start first with the Clipper system, as this will be the first chance for some light snow and snow showers Saturday Night into Sunday morning. This Clipper will move across the Midwest and to near Ohio, Saturday into Sunday AM. Some light snow and snow showers are likely across the entire region with areas North and West of PHL, having the best shot of some accumulating snow. My best estimate is for 1" to 3" north of PHL, and a Coating to 1" over DE and Southern NJ. Does this sound familiar ? You get the picture !

A Coastal Threat: Sunday PM
Now comes the tricky and complex part of this forecast. A transfer and secondary coastal storm is looking more likely to develop near the VA and Delmarva coast for Sunday and Sunday night. The Upper level pattern and trough axis will be critical in exactly where this storm forms. The latest computer models are showing a shift west and deeper amplification, which will allow this system to develop further south and closer to the coast. This is a very good trend for snow lovers in Delaware and NJ. With a huge ridge extending into Northwestern Canada, this would aid in amplifying the trough in the East. I should say help it too dig further south, and the associated Vortmax energy at the H5 levels, would help develop a Coastal Storm near the NC/VA coast. So overall I'm favoring a Coastal Storm to develop and give us our first big snowstorm late Sunday and Sunday night. Stay Tuned.

The latest 2 runs (00z and 06z) of the GFS are showing a coastal low just off the VA/Delmarva coast for later Sunday evening, as snow is falling from Eastern VA and north into DE and NJ. If this were to verify, much of DE and NJ would be looking at 3" to 6" of snow for Sunday night into early Monday AM. The QPF output is .25" to .50" for much of NJ and DE, so with 12:1 and 15:1 ratios, this would we a nice snow event. So this coastal needs to be watched closely, and could give areas south and east of PHL a nice snow event. I'll be watching this close during the weekend and give updates as needed. (Please see map below)

00z GFS Ensemble Members: For Sunday Night
7 of 12 members are showing a good hit for DE and NJ.
http://raleighwx.easternuswx.com/models/gfsensemble/members/00zf078.html

The Euro is showing a similar setup, but further east and just offshore where SE VA gets nailed with a 6" to 10" snowstorm and NJ is brushed with very little snow.

The latest NAM model is trending further south with the Clipper but is showing the transfer further north and offshore. This would be a nice hit for NYC and into Eastern New England, but a miss for the Delaware Valley. A classic Miller B, New England Bomb and snowstorm.

Please check back throughout the weekend, as I'll be tracking this possible snow event for Sunday and Sunday Night, and provide my forecast and more thoughts.

Take Care,
Ruggie