656 FXUS64 KHUN 120348 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 948 PM CST Tue Jan 11 2022 .NEAR TERM...(Rest of tonight) Issued at 948 PM CST Tue Jan 11 2022 The near term grids are in good condition this evening, with no significant changes made in this update. Models suggest that winds aloft will gradually back to the west-southwest and strengthen overnight, as a mid-level shortwave trough digs southeastward across the northern Plains. However, it appears as if high-level cloudiness associated with a weakening southern stream disturbance across eastern TX will remain to our south/west, resulting in a clear sky. Light/variable flow will continue in the boundary layer, as the region will remain within a ridge extending westward from a high centered across eastern NC, and this should provide a favorable environment for radiational cooling, once again. Lows will drop into the mid 30s near large bodies of water, and u20s-l30s elsewhere, with brief development of patchy freezing fog possible in a few of our deeper valleys between 9-13Z. .SHORT TERM...(Wednesday through Thursday) Issued at 310 PM CST Tue Jan 11 2022 A broad upper trough will swing through the TN Valley on Wednesday, with its axis moving to our east by early Thursday morning. Surface flow will remain from the south, filtering moisture northward and into the area. Despite some weak height falls, skies will remain clear during the day and combine with the southerly flow to send highs into the mid to upper 50s by Wednesday afternoon. Clouds will then increase during the evening hours, giving way to mostly cloudy skies and more mild overnight lows Wednesday night. With very little change in the pattern through much of Thursday, expect similar conditions with highs in the upper 50s. A trough will dig southward Thursday evening, and amplify to our east, while a weak frontal boundary moves through the region. Aside from an increase in cloud cover, this isn't expected to bring much impact to the sensible weather pattern over the TN Valley, with conditions remaining dry overnight. Temps will once again by mild, with overnight lows in the lower to mid 30s Thursday night. .LONG TERM...(Thursday night through Monday) Issued at 310 PM CST Tue Jan 11 2022 Upper ridging will build into the Plains on Friday, with strong north-northwesterly flow through the vertical column. CAA will persist through much of the day and temps will struggle to rise out of the mid to upper 40s on Friday. The ridge will dampen quite a bit as it slides eastward through the day, with flow aloft becoming zonal during the overnight hours on Friday. A fairly strong upper low will develop along the northern Rockies and then dig southeastward during the day on Saturday. Meanwhile, surface winds will shift to the south and increase, with moisture quickly returning to the area. Rain chances will increase from west to east on Saturday, with the higher PoPs during the afternoon and evening hours when the upper low moves into the Lower Mississippi Valley. Given the cloud cover and precip, temps on Saturday will only rise into the lower to mid 40s. Models have come into much better agreement with regards to the overall solution of this upper low. Where the 12/00Z ECWMF guidance kept the track of this low well to our south, the 12/12Z guidance keeps the low just to our south and almost in line with the 12/12Z GFS. As a result, precipitation is expected to continue into the overnight hours on Sunday and potentially through the morning hours. As is always the case with winter weather, the big question is how quickly temperatures fall as the as the cold front moves through and surface flow becomes northerly and whether moisture remains in place. Deterministic guidance keeps temps on the warm side, suggesting more of a cold rain. However, ensemble trends have continued to point towards temps dropping into the lower 30s as precip continues to fall Saturday night into Sunday. So the forecast was trended more towards the ensembles, with rain transitioning to snow by midnight and then snow continuing into the predawn hours. At this point, snowfall totals are expected to remain below one inch, given the light intensity and duration of snow. We should start to warm up on Sunday, with highs in the lower 40s and thus any accumulating snow will quickly melt during the day. We're still 4 to 5 days out so this is a pretty low confidence forecast. It'll be important to watch the trends over the next couple of models runs. A broad upper trough will generally dominate the eastern half of the CONUS on Monday and then quickly move off the east coast by Tuesday as ridging builds over the Plains once again. Little in the way of impacts are expected at the start of the new work week, with high in the upper 40s and lows in the upper 20s. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 631 PM CST Tue Jan 11 2022 VFR/SKC conditions will persist at the HSV/MSL terminals through the late morning hours, as high-lvl Ci associated with a weak southern stream disturbance moving southeastward across eastern TX should remain to our S/W. Although the combination of clear skies and lgt/vrbl winds may promote the development of patchy FZFG in local river valleys btwn 09-13Z, this should not impact the airports. Sct high clouds will return to the region late tomorrow morning, concurrent with the onset of light SSW flow in the low-levels that will occur as a ridge axis shifts further southward into the Gulf coast states. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ NEAR TERM...70/DD SHORT TERM...73 LONG TERM...73 AVIATION...70/DD For more information please visit our website at weather.gov/huntsville.