078 FXUS64 KHUN 100802 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 302 AM CDT Mon Jun 10 2019 .NEAR TERM...(Today) Issued at 302 AM CDT Mon Jun 10 2019 Across the greater Huntsville forecast area, generally quiet weather prevailed. Local and regional radars indicated light showers oriented approximately north to south just east of the AL/GA border. Otherwise with skies ranging from mostly clear over NW Alabama to generally cloudy east of I-65, night time low temperatures ranged in the upper 60s to lower 70s with light winds. Of more concern is the development of low clouds and possibly fog before daybreak. The fog/low cloud (10.3 - 3.9 micron) satellite view nicely indicated the lower clouds forming near and east of I-65. The microphysics view also nicely depicted these lower clouds. Clouds that were forming had cloud bases below 1000 ft AGL, that could cause higher elevation terrain visibility reductions and aviation concerns. We already have reduced surface visibilities at the Vinemont airport just north of Cullman and in Albertville, both locations in more elevated terrain. Forecast trends for the rest of the night are challenging, but tend more towards low cloud than fog formation. In a few hours with the advent of daybreak, low clouds will again rise and/or dissipate with mixing and heating. A surface low pressure system that caused the unsettled weather as of late has shifted east of the region. An upper trough axis more associated with that low was exiting the region, as another trough to our NW amplifies to the south and east. This deepening troughing, and the approach of a cold front moving eastward over the Mid South, will sweep across the Tennessee Valley today. Lift provided by the front, along with heating of a still moist airmass will bring a chance of more showers and thunderstorms from the mid morning to late afternoon. Rainfall totals should not be as high like the past few days, as drier air filters in from the west. High temperatures later today should be little cooler than yesterday - in the lower 80s vs mid/upper 80s. .SHORT TERM...(Tonight through Wednesday) Issued at 302 AM CDT Mon Jun 10 2019 The cold front by the early evening should be east of the AL/GA state line, with notably cooler and drier air filtering in from the NW. Shower activity likewise should end in the early evening. Yes there is still very cool air to our north, and it will be felt by sunrise Tuesday with low temperatures ranging in the mid/upper 50s. The last time our low temps were below 60 was almost a month ago in the middle of May. Highs on Tue should only warm to around 80. Normal high/low readings then are around 87/65. As a troughing east/ridging west pattern sets up over the lower-48, a reinforcing cold front approaching from the NW, and moisture from a "tropical" looking area of low pressure over southern AL/GA, will bring isolated to scattered showers/thunderstorms on Wednesday. The higher rain chances will be over NE Alabama and adjacent Tennessee, where the strongest forcing and deeper moisture will be realized. High temperatures should rise a bit more over NW Alabama into the lower 80s, while they stay in the upper 70s over the more eastern areas due to more clouds and higher rain chances. .LONG TERM...(Wednesday night through Sunday) Issued at 302 AM CDT Mon Jun 10 2019 The 500 mb trough axis should progress through the TN Valley Wednesday night, effectively ending rain chances for the area through late next week. High pressure filtering in will reinforce the dry trend with limited moisture advection. Below average temperatures will continue with highs in the upper 70s Thursday. Calm winds and mostly clear skies will set up ideal radiational cooling, allowing Thursday night to be our coolest with expected lows in the 50s - roughly 10 degrees below average for this time of year. High temperatures will steadily increase to the mid 80s Friday and then upper 80s on Saturday as the flow aloft becomes more zonal. A series of shortwave troughs will progress through the zonal flow late next weekend, bringing our next chance for showers and thunderstorms late Saturday through early next week. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) Issued at 1247 AM CDT Mon Jun 10 2019 VFR weather should continue into the overnight over most of area. However, with generally clear skies, light winds, and residual moisture from recent rainfall, areas west of Huntsville could experience predawn fog development. Given uncertainties on timing and locations, did not include fog in the TAF this issuance. But the formation of MVFR cloud bases look more probable after 09Z over areas near and west of I-65. A return to VFR conditions is expected in the late morning, as low clouds break up and drier air gradually filters over the region from the west. Light winds tonight will become NW after daybreak, increasing to around 10kt by 15z. Winds should veer more to the north in the afternoon in the 10-15kt range. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ NEAR TERM...RSB SHORT TERM...RSB LONG TERM...30 AVIATION...RSB For more information please visit our website at weather.gov/huntsville.