Important points for Monday night's potential winter storm
From James Spann - ABC 33/40 Weather Blog:
*TIMING: The main initial impact will come from 6:00 p.m. Monday through 12:00 p.m. Tuesday. There is some risk wintry precipitation could begin over far North and Northwest Alabama as early as 3:00 p.m. Monday. And, the far northern part of Alabama could have ice impacts through the afternoon Tuesday.
*IMPACT: Ice accumulation of 1/4 inch is possible along the I-20 corridor; this could lead to scattered power outages. Should the ice load be greater than forecast, outages could more widespread and last longer.
Travel will become difficult along and north of I-20. Initially, bridges and overpasses will become icy, road surfaces will become slick and dangerous later.
*PLACEMENT: Clearly the big issues will be along and north of I-20. The southern periphery of the ice zone is very hard to call. Some parts of Tuscaloosa, Birmingham, and Anniston could very well get away with a cold rain, while other parts of these cities could have enough ice for major travel impact. Snow is most likely along and north of U.S. 278 (Hamilton to Cullman to Gadsden).
*SECOND WAVE OF ICE? Concern is growing that a new wave down in the northern Gulf will bring potential for more freezing rain Tuesday night into Wednesday morning. Cold air damming (the wedge) will come into play, and the highest ice potential during time time frame could be over East-Central and Northeast Alabama. We will have much more on this Monday, but this second wave could make this a long duration winter weather event for some.
*CONFIDENCE: The overall confidence is high in the synoptic scale; the most difficult part of the forecast is the southern edge of the snow/ice zone near I-20. There is little skill in forecasting the ice/rain line this far in advance. And this line is very close to I-20.