Wednesday, December 07, 2005

Here Comes The Hype....doo doo doo doo

Round 2 of 'How Much Bread Can You Get At Your ACME In A Week'

For those who don't like technical stuff -- this is what matters: Very good chances of snow Friday but the best chances of a good hit will be I-95 and EAST. It will be a fast moving system -- in overnight Thursday/Friday, out before dinner time. Essentially expect traffic hell to break out all day.
I also felt the title was a Nice Beatles-esque quality to it. The problem is can we take a winter of it? Is it alright? I don't think I'll be able to make it to March before I want to launch the TV threw the window at the next live remote in North Delaware or the Wawa in Berlin, NJ to tell me it's flurrying. Sorry to pick on CBS 3 by throwing a still shot up there because it's not just you. 6, 10, 29, CN8, and I think a couple public access channels are guilty of said hype too. Oh I well I digress...

The slightly updated technical discussion is below. Enjoy...

We have a couple of features to worry about. A mid level (500 mb)low and an associated surface through are forecast to move east across the Central US along the Ohio Valley, spreading snow for places like Indianapolis, Cincinnati, and up towards Pittsburgh where there are Winter Storm Watches in place. While that strong mid-level system progs east, a coastal low will develop and move NE off of Cape Hatteras.

There are two schools of thought with this system and both give snow to Philly, but one drops more than the other. The ealry AM NAM model (an outlier) is progging a weak and VERY wet system to move through the area and I disagree with the solution it is kicking out. The NAM has had a notorious wet bias to it over the last few months. The NAM is kicking out about 5-6" for Philadelphia, which sounds reasonable, but much more N and W over the mountains and more along the coast. Sort of a snow shaft, but for the mountains I think the solution is being overdone at this point. The NAM is kicking that mid level feature more NE and to the north of the developing coastal low. This is preventing bomb out from occurring but also dumping more snow over North Central PA than I would prog for them (they're looking at 1 foot plus if you the NAM).


The other school of thought is where the GFS computer model, NOGAPS, Canadian, UKMET, and everyone else agree (Mid level system moves east and joins the developing and intensifying coastal low). The coastal bomb that doesn't move up the coast but ENE to NE along and out to sea. This event shapes up as better for places west but still gives the golden snow shovel to places in Jersey, Long Island, the immediate Southern New England Coast, and possibly Northern DE.

Concerns:

(1) Ice in Coastal Areas within 5 miles of DE and NJ Shoreline. Given that you guys will have snow cover through the next couple of days there is potential for an ice event when the flow off the ocean kicks in from that coastal low. The 45 degree water will be enough to warm the lower and mid layers of the atmosphere but given that there is snowpack there is potential for ice near the coast. Keep that in mind.

(2) The speed of the upper air pattern is tremendous. Over 150 kt jet will make this event FAST, QUICK, and hell for the AM commute. This is where I cannot buy the NAM solution because it is taking a mid level feature and shooting it further north than it should, given a flow that is WSW-ENE in orientation. There will be very little chance of a left turn out of the developing coastal low, and thus it will be forced to shoot ENE.


EARLY calls :

I-81 Corridor 2-5
Poconos 2-5
Lehigh Valley/Reading/Lancaster 3-5
Philadelphia 4-8
Jersey/DE 5-8/3-6 within 5 miles of the coast with rain or ice mix for S Jersey/DE.

(I will have a map up with these calls by 5 PM today and a final forecast call, if needed, by Thursday at 9 AM)

Timing, In between 2 AM S, 7 AM Far N, out within 8-10 hours of start time.