706 FXUS64 KHUN 051000 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 500 AM CDT Thu May 5 2022 .NEAR TERM...(Today) Issued at 500 AM CDT Thu May 5 2022 Regional surface observations indicate that the local CWFA remains to the north of a stalled frontal boundary this morning, with very light northeast winds and a gentle gradient in both temps/dewpoints from NE-to-SW. The presence of high-level clouds has limited the coverage of fog thus far, but we would not be surprised to see a few reports of reduced visibility through sunrise. Over the course of the day, a mid/upper low currently positioned along the CO-KS border will gradually intensify as it shifts eastward across western KS. As this occurs, a developing surface low will lift northeastward from western OK into eastern KS/western MO, with a warm front expected to lift northeastward across our region. There are still indications that scattered thunderstorms may develop early this afternoon along a corridor from southern IL into Middle TN, which would be in the general vicinity of the warm front. It is unclear how much of this activity (if any) will impact our area, but we have maintained slightly higher POPs across the northeast to account for this reasoning. That said, as temperature warm into the m-u 80s, the combination of MLCAPE in the 2000-3000 J/kg range and 35-45 knots of deep-layer shear would support severe multicell clusters or perhaps even supercells, with an attendant risk for large hail and damaging winds. Warm frontal thunderstorm activity should progress northeastward and away from the region late this afternoon. .SHORT TERM...(Tonight through Saturday night) Issued at 500 AM CDT Thu May 5 2022 Attention this early evening will turn to the west, where a somewhat unorganized but severe QLCS will be crossing the Mid-South and Lower MS Valley regions, well ahead of the synoptic cyclone's surface cold front. Either the remnants of this squall line or perhaps the development of new convection along its outflow will likely begin to impact western portions of the forecast area by mid-evening. As the the mid/upper low over KS becomes negatively-tilted while spreading east-southeastward across the Ozarks overnight, the low-level jet will increase to 35-45 knots across the TN Valley, which could result in fairly rapid upscale growth of this convection across the local area late tonight, within a moist/unstable environment featuring dewpoints in the mid 60s. Storms will become increasingly organized with time as deep-layer shear increases to 45-55 knots, and several recent CAMs even show a small bow echo moving northeastward across our area around Midnight. Damaging winds and large hail will be the main threats with the storms, but given the magnitude of low- level flow, a couple of tornadoes will also be possible. At this point, it is still unclear how quickly this activity will move northeastward during the early morning hours, making coverage and intensity of storms along the actual cold front uncertain. Regardless, the front will likely cross the region between 14-20Z on Friday, and could be accompanied by another band of strong-severe thunderstorms with similar threats, given comparable values of instability and shear. Light-moderate west-northwesterly flow will advect a cooler and drier airmass southeastward into the region from late Friday afternoon through Saturday. Periods of broken low clouds and isolated-widely scattered showers will also help to keep temps cooler, with lows on Saturday morning in the mid 50s and daytime highs in the upper 60s- mid 70s. Clearing skies and diminishing winds will enhance radiational cooling on Saturday night, with lows on Sunday morning in the lower 50s. .LONG TERM...(Sunday through Wednesday) Issued at 500 AM CDT Thu May 5 2022 Consensus guidance from the latest suite of global models suggests that the mid/upper low discussed above will broaden and drift slowly southward off the Mid-Atlantic coast early next week. An amplified mid-level ridge will build northward into the Great Lakes region from a strong subtropical high over central Mexico, and this will lead to at least a brief period of warm/dry conditions through Tuesday, with highs in the u80s-l90s common for most valley locations. There are indications that the cyclone to our east may begin to retrograde on Tuesday night/Wednesday, perhaps forcing a backdoor cold front southwestward across our region on Wednesday. Although a few showers and thunderstorms would be possible if this was to occur, probabilities at this point appear too low to include in the forecast grids. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 1050 PM CDT Wed May 4 2022 VFR conditions will continue throughout the TAF cycle. There could be some patchy fog near daybreak with a stalled surface front just to the south but do not have enough confidence to include in the TAFs at this time. A warm front will lift northwards across the terminals later this morning with winds veering around to the south by 15z. These southerly winds could gust up to near 20 kts at times. Scattered afternoon showers and storms will develop in the warm sector. There is enough confidence now to include SHRA and VCTS in the TAFs after 00z with better model consistency. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ NEAR TERM...70/DD SHORT TERM...70/DD LONG TERM...70/DD AVIATION...MA For more information please visit our website at weather.gov/huntsville.