Thursday, December 15, 2005

Final Call

Given that the temperatures for this event will be very close to freezing tonight, if temps are two or three degrees warmer than forecast, icing may not be a concern. Best to side with the cautious forecast than not say ice and get nailed. Here's the thinking I used this morning:

S & E of 295/NJ Turnpike, C & D Canal: 90% rain. May start as sleet or snow but will quickly change over. Not a big deal but you will get rained on to the tune of around an inch.

N & W of 295 - Suburban PA Counties/Trenton/NE Maryland: Snow start. The Quakertown-Pottstown-Coatesville corridor could get an inch or two at the start with Philadelphia getting a coating of snow. Snow will change to mix of sleet/freezing rain first in Philadelphia and the changeover will work its way NW. The ice will change to rain more slowly from SE to NW, with the areas closest to Quakertown-Pottstown-Coatesville getting some ice accumulation.

Lehigh Valley/Berks/Harrisburg: Snow start. 1-3" with the best chances of 3" being NW New Jersey down through Easton. Snow will change to ice from south to north with significant ice accumulations possible for Harrisburg up through the Lehigh Valley. Ice should change to rain very slowly across the area with the event ending as rain. Damage will be done though as many areas should get decent ice event.

Poconos/Blue Mountain Corridor: Snow start. 2-4" with the best chances of 4" being Scranton/Wilkes-Barre area. Mix with sleet and freezing rain. Changeover to ice in places but not everywhere.

Central PA (N & W of pink line): Mostly snow. Some mix at times with ice and sleet. 6"+ expected.

Timing: Starts in Philadelphia between 2-5 PM.

Other Forecasts for Philadelphia:

CBS3: Starts 3-4 PM, Coating of snow.
6ABC: Starts 4-7 PM, Coating of snow.
NBC10: Starts 4-6 PM, Coating to an inch.
FOX29: Starts 4-6 PM, Coating to an inch.
NWS PHL: Little or no snow accumulation.

Low pressure will be tracking NE to the east of the I-95 corridor but inland throughout the next 24 hours. This low is currently spreading ice, sleet, and snow for the Appalachians and Piedmont of the SE. Moisture from this storm will be spreading up the East Coast throughout the day today. The storm should end by early to mid morning on Friday. Temperatures will be near freezing Thursday night Lehigh Valley to 35-38 Philadelphia to 40-45 South Jersey.

Friday will be a day featuring windy conditions as the low passes by with winds switching to the west and then northwest. Temperatures may fall in the afternoon as cold air comes back into the area after an initial 3-5 degree spike in temps early in the day.