Area Forecast Discussion
Issued by NWS Louisville, KY
Issued by NWS Louisville, KY
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052 FXUS63 KLMK 171503 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 1103 AM EDT Wed Jul 17 2024 .KEY MESSAGES... * Periodic showers and storm continue through today, with a northwest to southeast drying trend expected tonight behind a cold front. * Cooler temps and lower dewpoints expected Thursday and Friday. * Gradual warm up this weekend with increasing mugginess by early next week. Shower and storm chances also return in that timeframe. && .UPDATE... Issued at 1103 AM EDT Wed Jul 17 2024 After a soggy morning with training showers and storms, we are in a lull of precip activity as the environment is somewhat worked over with MLCIN present and weaker moisture convergence. However, as we get into the afternoon hours, do expect to see CIN deteriorate as we get some daytime heating. With cloud cover lingering throughout the day, the question remains how much heating and destabilization we will realize. Do expect some isolated to scattered showers and storms to redevelop along and ahead of the front this afternoon, but knowing exactly where is challenging. Model soundings for this afternoon do show a decent amount of instability available, but weak shear will keep cells unorganized and messy. High PWATs will promote heavy rainfall rates with any shower or storm. Some increase in coverage may be possible this evening as the front passes just south of the Ohio River, but we`ll see PoPs taper off from north to south gradually through the night. Current forecast is on track and no changes are planned at this time. .UPDATE... Issued at 600 AM EDT Wed Jul 17 2024 Precipitation across the region has begun to transition to light/moderate in nature as instability wanes and the main lifting mechanism (outflow boundary) for convection has pushed south of the TN border. The flood threat going forward should be minimal, so the flood watch has been dropped a few hours early. && .SHORT TERM /THROUGH TONIGHT/... Issued at 309 AM EDT Wed Jul 17 2024 An east-west oriented band of showers and storms along a boundary continue this morning across the width of Kentucky. Storm motions have been generally been parallel to this boundary, which prompted the issuance of a flood watch. Outflow boundaries from the storms have aided in the development of new convection generally to the south where better environmental parameters exist, and this has helped to limit the overall storm training as the line propagates southward. These storms are very efficient rain producers, as evident of some recent obs... for example, the Marion County KY Mesonet site recorded an inch of rain in nearly 15 minutes! So, while the storm training threat has steadily decreased this morning, localized flooding issues are still possible. Shower/Storm activity should begin to taper down in coverage and intensity toward or shortly after dawn. Details regarding how the rest of the day will play out remain uncertain. It does appear likely we`ll see some sort of lull in precipitation after the current waves fizzles out, but models vary on when/where new showers and storms will develop as a slow moving frontal boundary sinks southward. Model performance over the last few days has been sub-par at best, particularly with the finer mesoscale features, so it`s hard to put confidence into a particular solution or outcome. Based on some of the mesoscale and weak synoptic forcing at play, have a general increase in PoPs as we go into the afternoon hours, with drying/partial clearing from northwest to southeast as the front slides through later today into tonight. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Issued at 309 AM EDT Wed Jul 17 2024 Much cooler/drier post-frontal conditions can be anticipated Thursday as northerly winds continue to pump in an air-mass with Canadian (albeit, highly modified) origins. The surface high will slowly track from the Midwest into the Great Lakes region Thursday and Friday, keeping us solidly in a northern flow regime. Highs both of these days will likely top out in the low/mid 80s with dewpoints ranging from mid 50s to low 60s. The upper level pattern will begin to shift going into the weekend and early next week as a baggy, nearly stationary trough takes shape over the Plains and Missouri Valley. Our region will be on the eastern periphery of the trough, and we`ll see a gradual uptick in low level moisture and mugginess going into next week. The increased moisture will also lead to increasing shower and storm chances during this timeframe. && .AVIATION /12Z TAFS THROUGH 18Z THURSDAY/... Issued at 600 AM EDT Wed Jul 17 2024 A narrow line of showers and thunderstorms that have formed along a boundary across western/central KY will continue for the next several hours and could eventually impact the BWG terminal as outflow boundaries develop new convection southward. Areas farther north could see showers/storms come close but think many of those will stay dry through the early morning hours. We should see a brief lull in activity after dawn but additional shower and storm development is likely this afternoon as a frontal boundary sinks into the region. Where and when these storms form remains quite uncertain, but plan on highlighting potential with VCSH for now. Additionally, just ahead of the front, cigs could drop to MVFR levels by mid morning for a few hours but should rise to VFR levels by early afternoon. Winds will gradually turn from south or southwest to northwest behind the front. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...None. IN...None. && $$ UPDATE...DM/CJP SHORT TERM...DM LONG TERM...DM AVIATION...DM