936 FXUS64 KHUN 100010 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 710 PM CDT Sat May 9 2020 .UPDATE... For 00Z TAFS. && .NEAR TERM...(Tonight) Issued at 123 PM CDT Sat May 9 2020 Northerly flow will diminish early this evening as the center of high pressure over northeast AR drifts east into TN this evening. The ridge then elongates into a west-east fashion across the region. This will provide good radiational cooling conditions tonight with light flow. A shallow radiation inversion will develop, with valleys dropping into the m30s with patchy to areas of frost likely, especially in southern middle TN and northeast AL. However, will keep the Frost Advisory areawide to cover patchy frost in other locations. The higher elevations may be spared above the shallow radiation inversion and near area lakes. .SHORT TERM...(Sunday through Monday night) Issued at 123 PM CDT Sat May 9 2020 A weak mid level trough axis noted at 8h and 5h will push through early Sunday morning. Only a few wispy high clouds may drift by and just a hint of cool advection aloft. A stronger upper shortwave/low will drop southeast through the lower Great Lakes through the day swinging another unseasonably strong cold front southeast through the OH and TN valleys later in the day. The front will likely move through dry, although the GFS hints at light showers in middle and eastern TN. For now, will keep the PoP a silent 5% in this area through Sunday night. After highs in the u60s-l70s Sunday afternoon due to deeper mixing and low level heating, cold advection will drop temps back into the u30s-l40s in southern TN and l-m40s in north AL. The frontal system and airmass will drop temps back a good 5-8 degrees from Sunday to Monday's highs, so only l-m60s in valleys Monday afternoon and u50s atop the higher Cumberland Plateau areas. Record low max temps appear to be safe that day (11th of May) with HSV being 54 in 1960 and MSL 53 in 1960. Warm advection/isentropic ascent in mid levels will stream mid/high clouds across TN and north MS/AL Monday night. This should keep temps a bit milder with lows in the l-m40s Tuesday morning. .LONG TERM...(Tuesday through Friday) Issued at 123 PM CDT Sat May 9 2020 Sfc high pressure will be centered over the region on Tuesday, keeping dry but cool conditions in place through much of the day. As flow becomes more easterly aloft, will see an increase in cloud cover throughout the day, which will help limit temperatures from rising above the mid-upper 60s. Models suggest a sfc front will stall near the Tennessee River by Tuesday evening, and if this comes to fruition we could see a few showers form along the boundary late Tuesday/early Wednesday. Will see a continued warming trend, as the sfc high moves northeast toward the Atlantic Coast, and winds become more southerly. Expect high temperatures to reach the 80s by Thursday, with continued warm air and moisture advection out ahead of a broad upper trough that could create an active period over the Great Plains. Will remain dry through Thursday, but chances for rain and thunder will return over the weekend as the aforementioned disturbance shifts closer to the Southeast. Expect high temperatures to remain in the 80s into the weekend, and lows in the 60s. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 710 PM CDT Sat May 9 2020 VFR conditions will continue overnight at both terminals, with a sct coverage of Ci expected to spread northeastward across the region from a broad trough of low pressure over the southern Gulf of Mexico. Regardless of the increasing presence of high-lvl clouds, some patchy fog will be possible in local river valleys, mainly btwn 04-13Z, but threat for occurrence at the terminals is not high enough to warrant vsby reductions in the forecast at this point. Sct high- based Cu and Ac will likely develop by 16Z as diurnal heating/mixing increase late tomorrow morning. Lgt/vrbl sfc flow associated with a ridge of high pressure across the region will assume a more pronounced WSW component by 16Z, as a cold front begins to drop southeastward into the Lower OH Valley. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...Frost Advisory from 1 AM to 8 AM CDT Sunday for ALZ001>010-016. TN...Frost Advisory from 1 AM to 8 AM CDT Sunday for TNZ076-096-097. && $$ NEAR TERM...17 SHORT TERM...17 LONG TERM...25 AVIATION...70/DD For more information please visit our website at weather.gov/huntsville.