Area Forecast Discussion (AFD)
Issued by Huntsville, AL (HUN)
301 FXUS64 KHUN 212057 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 257 PM CST Tue Nov 21 2017 .NEAR TERM...(Tonight) Issued at 257 PM CST Tue Nov 21 2017 Lower altitude clouds associated with a surge of moisture moving NNE from the Gulf coast continued along and east of the AL/GA border. They earlier produced lower ceilings (mostly MVFR) reductions at Ft Payne and Scottsboro. Those clouds were generally moving NNE while the "line" of clouds drifted slowly to the east. More higher altitude clouds otherwise were moving across the Tennessee Valley from the west; part of a trough extending south of Hudson Bay located upper system swinging by. Despite the scattered to broken deck of high clouds, some warm air advection and what of the sun's long wave radiation to make it to the ground, highs across the area have risen into the upper 50s and lower 60s. A few mid 60s may be realized over the next hour or so, before the usual evening cooling commences. A strong but dry cold front will be moving across the Valley during the night time. This front, now moving across areas from NW Ohio, to near the Missouri Bootheel and SE Oklahoma was being pushed southward by a chilly Canadian high moving to the southeast from Saskatchewan the the MT/ND border. The front should reach far NW Alabama around 8-9PM, greater Huntsville area before midnight, and SE of Ft Payne by 2AM. SW winds will become northerly behind the front. With little moisture before/after the front, no rain is expected. Colder air behind the front will take a bit to arrive, but will make for a cold predawn of Wednesday, with lows falling into the lower and mid 30s. .SHORT TERM...(Wednesday through Friday night) Issued at 257 PM CST Tue Nov 21 2017 The busiest travel day of the year will feature mostly sunny skies but colder conditions in the wake of the frontal passage. After mild conditions today, highs on Wednesday will barely reach the lower 50s. NW winds will increase into the 5-15 mph range, making for almost "brisk" conditions in comparison to today. With colder air more entrenched, another cold night Wednesday night with lows in the upper 20s and lower 30s. Thanksgiving 2017 will warm up a tad more Wed, with highs warming into the mid 50s. Normal high temperatures for reference on the 23rd are around 61 in Huntsville and 60 at Muscle Shoals. After a chilly Thursday night with lows around freezing, dry weather will continue for the Friday and Saturday time frame. Highs on Friday should rise near 60, and the lower 60s during Saturday. .LONG TERM...(Saturday through Monday) Issued at 257 PM CST Tue Nov 21 2017 This weekend, we can be thankful for the lingering dry and cool conditions, especially if traveling. Southerly flow at the sfc will help Saturday's high temps warm up towards 60 degrees. Northwesterly flow aloft will persist as a ridge remains anchored across much of the western half of the U.S and a broad trough across the eastern half. A shortwave will slide southeast out of the Northern Plains Friday night into Saturday as the sfc low stays north of the Great Lakes. The associated cold front will sweep into the area by Saturday afternoon. The front will bring an increase in cloud cover but no rainfall. Temps will fall into the mid 30s Saturday night with cold air advection and cloud cover moving back out. Broad sfc high pressure building into the region will tighten the pressure gradient to increase CAA on Sunday and with northwesterly flow aloft still in place, Sunday's high temps will be around 10 degrees cooler than Saturday. Look for highs in the lower 50s and overnight lows in the upper 20s/lower 30s. On Monday, southeasterly winds return as the sfc high and ridge shift a little eastward, but will not see a big improvement in temps. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) Issued at 1159 AM CST Tue Nov 21 2017 VFR conditions should continue across the TAF sites. An area of stratus moving northward from the Gulf across eastern Alabama should remain east of the KHSV terminal into the evening. Otherwise periods of high clouds will continue. A dry cold front arcing from north and central Indiana, to near St Louis and Amarillo will move to the southeast, moving across the region tonight. No weather of consequence is expected, except that S-SW winds will become NW after the front passes. Northwest winds should increase into the 10-20 kt by late Wednesday morning. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ NEAR TERM...RSB SHORT TERM...RSB LONG TERM...JMS AVIATION...RSB For more information please visit our website at weather.gov/huntsville.