Saturday, February 24, 2007

SOME SNOW & ICE FOR SUNDAY INTO MONDAY MORNING FOR THE DELAWARE VALLEY REGION




SUNDAY: 2/25/07
ISSUED: 7:00 AM
MY FINAL CALL: FOR THE DEL. VALLEY

DISCUSSION:

Once again the Delaware Valley Region is on target for a Snow and Ice event, for Sunday into Monday morning. Most areas will see mixed precipitation, starting out as Snow and Sleet between 10:00 AM and 2:00 PM on Sunday. This precipitation will then change to Freezing Rain and Sleet later Sunday afternoon and night, over SE PA, Northern DE, Interior Southern NJ and into Central NJ.

This could cause so big problems with Moderate Icing. LNS, PHL, ILG, and TTN, have the best chance for this threat. Snow and Sleet accumulations of 1"-3" are likely at the onset of the precipitation, with moderate Icing to follow Sunday night, before changing back to a period of snow before precipitation ends during Monday. Coastal sections of Central/Southern NJ into Central and Southern DE, will be mainly Rain, but could start as a brief Mix of snow and Sleet at the onset (<>

The reason for all this mess is a low pressure system moving into the Midwest Tonight and tomorrow, Precipitation will break out well ahead of the storm and move into our areas on Sunday. A cold High Pressure system in Hudson's Bay will continue to nose down into the Northeast. This will setup a CAD signature of low level cold air, similar to the Valentine's Day Storm, setting the stage for Sleet and Freezing Rain on Sunday Night. The Midwest storm will weaken on Sunday but will also bring in milder air aloft from the SW, this will allow an overrunning situation as low level cold air is filtered southward from our High to the North and Milder air is forced over the top from the 850 mb and surface Low in the Midwest.

A weak secondary Low pressure system will develop Sunday night into Monday Morning off the Delmarva coast, as the energy from our weakening western system transfers to the coast. This will also aid in holding the low level cold air in place as NE winds prevail. Temperature in the upper 20's and lower 30's on Sunday night will be just cold enough to allow for moderate Icing on trees and power lines, and roads will become Icy in some areas. So problems will begin Sunday Night into Monday morning as Ice accumulates on surfaces. All this may end as a period of Light snow or Sleet later Sunday Night into Early Monday, as the storm moves Northeastward and off the NJ coast. This may cool the layers aloft just enough to change the precip. back to snow as it exits. Some additional accumulations are likely from PHL south & East, Also further North into ABE and Northern NJ, some additional accumulations likely.

Take Care,
Ruggie

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