Sunday Evening Forecast Discussion – Sunday 6:30 p.m.
September 16, 2012 Leave a comment
A surface ridge has shifted eastward since yesterday toward the Mid-Atlantic coast, with light and variable winds across Central Alabama. A couple of boundaries have moved northward today across the state and helped to spark off some showers and thunderstorms this afternoon across the area, as overall low level moisture from the gulf has increased over the region ahead of our approaching upper trough, currently over Texas. Southwest flow ahead of the trough will aide in pushing a series of shortwave impulses northeastward across Central Alabama tonight thru Monday night. Precipitable water has risen today with onshore flow at 1.53 on the 12z model run. Although satellite blended precipitable water showed values in the southwest counties as high as 1.8. No major changes in the overall forecast thinking for our front as still expecting it to push through on Tuesday. Before all is said and done anywhere from 2-4 inches of rainfall are possible between now and late Tuesday. An inverted surface trough over the northwestern gulf should continue to help increase our available moisture.
For Wednesday, on through the weekend in our extended forecast, models diverge some. The Euro looks similar to yesterday with significant and much cooler and drier air moving in late Tuesday into Wednesday with and good push from the upper level trough that digs across the great lakes and provides good northwestern flow through the end of the week trying to push a second cold front over next weekend. The GFS breaks off a piece of lower pressure over Florida from the front and rides it over the latter part of the week westward, increasing our moisture back rather quickly. In the Euro looks to be most likely for the extended forecast as the upper flow looks to bring significant drier air into the area, it should build the surface high over the air and prevent the GFS solution from coming to fruition which would equal a cooler drier latter half of next week.