Expires:No;;148154 FXUS63 KLMK 040844 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 344 AM EST Wed Dec 4 2024 .KEY MESSAGES... * There is a very low chance for brief freezing sprinkles through 10 AM. Confidence in this remains low, and most should stay dry. * Windy conditions expected today with gusts of 35-40 mph possible. * Light precipitation tonight and a quick temperature drop may result in scattered slick spots on roads Thursday morning. * Cold wind chills in the single digits Thursday morning and teens in the afternoon. * Cold temperatures Thursday night, with the traditional cold spots dropping into the single digits by Friday morning. && .SHORT TERM /THROUGH TONIGHT/... Issued at 343 AM EST Wed Dec 4 2024 We are moving into a dynamic 24 hours of weather this morning. Sfc high pressure is now centered over the Southeast, while a deepening low pressure system is moving southeast over Ontario. A tightening pressure gradient between the two systems is resulting in strengthening low-level SW flow and WAA this morning. Skies are clear east of I-65 as of this writing, but a band of clouds on the leading edge of a 45 kt LLJ is quickly advancing eastward over the western half of KY. Temperatures were able to fall into the upper teens to mid 20s, but increasing cloud cover and WAA will result in gradually rising temperatures through daybreak. We look to remain largely dry through the morning hours. There is still a non-zero chance for brief, patchy freezing drizzle through the mid-morning hours. However, moisture depth is limited to 2-3 kft with cloud bases at 4-5 kft AGL. A noteworthy Sfc-900 mb dry layer should prevent hydrometeors from reaching the sfc, despite the presence of weak low-level isentropic ascent and the thin saturated warm layer aloft. Given the low confidence, any impact is unlikely. However, we will monitor radar trends closely through the morning. Beyond mid-morning, low-level wind fields continue to increase as the strong low pressure system rotates over Lake Superior and southern Ontario. As sfc temperatures climb under partly to mostly cloudy skies, low-level mixing looks sufficient to produce 30-40 mph wind gusts. Plan on highlighting the wind potential in a Special Weather Statement. Synoptic scale ascent and moisture depth increase late this afternoon into tonight. The potent mid-level vorticity maximum rotates over the Lower Great Lakes and Upper Ohio Valley as the strong cold front sweeps southeast through the area. Isolated showers will be possible 21-00Z this evening, with scattered showers most likely between 02-09Z tonight. During this window, the best chance (greater than 40% chance) will be northeast of a Salem IN to Campbellsville KY line. P-type looks mainly liquid through about Midnight, with a changeover to scattered snow showers for the 12-4 AM time frame. This is a very light QPF event, but any scattered snow showers tonight could produce a quick dusting. Temperatures plummet early Thursday morning with very strong CAA in the wake of the cold front. Temperatures are expected to drop into the teens to 20s by daybreak. Precipitation will likely diminish by the 09-12Z time frame. But given the light QPF overnight and quick temperature crash, some scattered slick spots will certainly be possible for the Thu AM commute. This concern is highest from southern IN southeast through north-central KY and the Bluegrass Region. In addition, NW winds will remain fairly breezy in the strong CAA regime. In short, expect a brutal Thursday morning with wind chills in the single digits to teens and possible slick spots on roads. Plan ahead and give yourself some extra time for the commute to work/school. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Issued at 343 AM EST Wed Dec 4 2024 Thursday... The low pressure center will be over the eastern Great Lakes by Thursday morning and the associated cold front will have pushed through the region. Thursday will feature strong CAA, a departing upper trough, and surface high pressure building into the region. In the morning, breezy northwest winds and temperatures in the teens and low 20s will lead to wind chills in the single digits. As the low pressure center progresses northeast, the pressure gradients and winds will relax over the Ohio Valley. Skies will quickly clear behind the front, however, strong CAA will suppress diurnal heating keeping high temperatures near cold max record for some climate sites and wind chills in the teens. Amongst ensembles, there is only a 20-25% chance of exceeding 29F at BWG and a 20-25% chance of exceeding 28F at SDF. Highs on Thursday are expected to be in the mid-upper 20s with a few spots in the southern tier of counties brushing 30 degrees. Thursday Night - Sunday Morning... High pressure will broaden and drift over the region through the end of the week and into the weekend. This will allow for sunny skies, dry conditions, and gradually warming temperatures each day. Sunday into Early Next Week... By Sunday, an upper level low stationed over the southwestern CONUS will begin to push eastward. This will lead to amplified upper ridging over the Ohio Valley and southwesterly flow in the low levels. We will likely see slightly above normal temperatures and returned moisture Sunday and Monday. At the same time, troughing over the northwest CONUS will begin to swing through the Rockies and Plains. Uncertainty with these systems is in their interaction and phasing beyond Monday. However, there is increasing confidence that Sunday and the early part of the week will feature above normal PWATs, a well saturated column, and widespread rain showers. The EFI is still showing a small signal for a heavy rainfall event. Ensemble probabilities show a 70% chance of exceeding 1.0 inches QPF and a 20% chance of exceeding 2.0 inches QPF. && .AVIATION /06Z TAFS THROUGH 12Z THURSDAY/... Issued at 1255 AM EST Wed Dec 4 2024 Impacts: * Marginal LLWS at HNB/SDF this morning. * Gusty winds from the SSW, especially after 15Z. Discussion: Mostly VFR conditions during this forecast period. The primary aviation impact will be wind. Southerly sfc winds will gradually increase through the early to mid-morning hours as a strengthening SW LLJ overspreads the area. This will produce brief marginal LLWS conditions mid-morning, but sfc winds will also be increasing out of the SW. SW winds are forecast to gust to 30+ kts between 15-21Z today ahead of a strong cold front. We will stay mainly dry during the daytime due to limited moisture depth. SCT showers are likely to develop late this evening and overnight as the cold front sweeps through the region. Highest confidence in prevailing SHRA is at LEX/RGA. A brief changeover to snow showers will also be possible late tonight near the end of this TAF period. && .CLIMATE... Issued at 343 AM EST Wed Dec 4 2024 ================== Near-Record Cold Max Thursday ================== Thursday 12/05/2024 Max T Fcst/Cold Max (Year) Louisville: 28/27 (1895) Bowling Green: 29/32 (2008) Lexington: 26/22 (1895) && .LMK WATCHES/WARNINGS/ADVISORIES... KY...None. IN...None. && $$ SHORT TERM...EBW LONG TERM...SRM AVIATION...EBW CLIMATE...SRM