Significant to Major Snowstorm, Likely Tuesday into Wednesday

Issued: Friday 2/9/07
Time: 6:00 PM

The First Significant/Major Snowstorm of the season to impact much of the Mid-Atlantic Region into portions of New England from late Monday into Wednesday.

The hardest Hit areas will be Central and Northern VA, much of MD, Eastern PA, NJ, and DE, and possibly into Eastern Portions of New England. These areas could be looking at 6" to 12" amounts with some areas receiving over 12". New England lesser amounts for now.

Technical Discussion:

All ingredients for a Significant to Major Winter Storm, are now coming together, for much of the M/A States and portions of New England, as we head into the early and middle part of next week.
The Upper Level pattern continues to support a trough over the Eastern US. As an East-West oriented or lobed P/V (Polar Vortex) positions itself north of the Great lakes into Quebec Canada (SE Canada). The P/V will continue to allow a cold West and NW flow of air over the M/A and NE Regions.

A very large and strong High Pressure system, will be draped across the Canadian/US border from the Upper Plains into the Great Lakes early next week, as high pressure slowly builds Southeastward from Central Canada over the weekend. The combination of this High pressure system to our NW, and a lobed P/V to our North in SE Canada, will allow a cold air supply too continue from The Northern Branch as we head into Next week.

The Southern Stream or Sub Tropical Jet (STJ) will begin to open up, and low pressure will develop near Texas on Monday. This southern stream will position itself from the Southern Plains, east to the M/A coast. It now appears the Northern and Southern Branches will phase in the east, as a shortwave Vortmax enters the picture, and slides eastward.

At the surface low pressure will begin developing near Texas on Monday then move eastward to the Tennessee Valley on Tuesday. Precipitation will develop out ahead of the system on Monday and snow will develop over the lower Ohio Valley into WV and VA Monday afternoon and night. As the S/W enters the picture, the surface low will move east to the Carolina coast on Tuesday, and begin to slowly intensify as it reaches the Coast. Snow will spread into the entire M/A region and could become heavy in much of VA. but later in the day, and during the evening towards DCA and PHL.

By Wednesday morning, the low should be off the NJ coast and begin Deepening quite rapidly as phasing is well underway. The New 12Z Euro is now suggesting the storm moves Northeastward up the coast and brings moderate to heavy snowfall for portions of Eastern New England. Other models such as the 12z GFS are moving the storm ENE and out to sea. This scenario would bring lighter snow only to SE New England. This is the biggest uncertainty at this time. Most models are in strong agreement that The Mid Atlantic States get the brunt of this storm. I'll be doing a final call and discussion with a detailed Snowfall map, Sunday night or Monday on this Storm.

For now here are "My Preliminary" 1st Call Snowfall Estimates for some selected Cities and Areas.

In Virginia:

LYH/ROA: 8"-12"
CHO/DCA: 8"-12"
RIC: 4"-8"

In MD/DE/NJ

BWI/ILG: 8"-12"
South Jersey and all of DE: 8"-12"

In PA:

PHL: 6"-10"
LNS: 4"-8"
RDG/ABE: 3"-6"

In NY and New England: (Very Questionable)

NYC: 3"-6"
Southeastern and East Central New England: 3"-6"
BOS: 2"-4"

Take Care,
Ruggie