Saturday Evening Forecast Discussion – 7 p.m.
December 29, 2012 Leave a comment
An active pattern will continue with multiple upper level impulses traversing across the area bringing us at least a couple rounds of rain showers beginning early in the week. Therefore, cloudy/wet and cool will generally be the norm over the next 7 days here in Central Alabama.
Starting with today, residual low level moisture combined with lift provided by an upper level shortwave pushing east thru the Ohio Valley has helped produce some light drizzle/flurries across the northern half of Central Alabama. Sounding profiles show a very shallow moist layer below 900mb, with extremely dry air in the mid an upper levels. We could still see a few reports of light drizzle and/or flurries across the north thru the remainder of the evening before the shortwave exits the region. An expansive stratus deck has held tough across the state for much of the day, unlike what model guidance had suggested, as usual. Cloud cover should slowly decrease from southwest to northeast late this evening and overnight. Low temps tonight will depend on how fast skies can clear and wind speeds. Still expect wind speeds to remain near or above 5 mph thru the night. So even with clear skies, winds should keep true radiational cooling from taking place. Regardless, temps will still fall into the low/mid 20s. Winds should also help prevent fog formation.
Surface high pressure will build in from the west on Sunday bringing mostly sunny skies and dry conditions to the area. This could perhaps be our only fair weather day for a while, so if you have any outdoor chores Sunday would be the day to get those done. Afternoon highs will still be several degrees below normal, with low 40s north to low 50s south.
A broad upper trough will approach the Rockies on Monday and remain nearly stationary thru Wednesday. Several impulses rotating around the eastern side of the trough will bring rain chances to the Southeast on multiple days during the work week. The first round will come late Monday into Tuesday, with another late Wednesday into Thursday. Cirrus clouds should begin to stream into the are Sunday night in advance of the first impulse. Rain chances will increase from northwest to southeast Monday night and Tuesday as a surface low treks northeast across the state and drags a cold front into the area. This front is likely to stall somewhere across the area on Wednesday as the upper flow becomes zonal, with rain chances continuing south of the boundary. The models are now developing yet another low in the central Gulf late Wednesday and then pulling it northeast into northern Florida on Thursday. Overrunning precipitation should spread northward across the area during this time. The good news, depending on how you look at it, is that temps will remain too warm for wintry precipitation and there will be no instabilities to work with for severe weather. Temps for much of the week will be at or below normal.