612 FXUS63 KLMK 220539 AFDLMKArea Forecast Discussion National Weather Service Louisville KY 139 AM EDT Mon Sep 22 2025
...Updated Aviation Discussion...
.KEY MESSAGES...
* Expect additional showers and storms to develop in the early morning hours Monday
* Another chance of strong to severe storms are possible Monday afternoon and evening. Main impacts remain gusty winds, hail, and brief heavy rainfall.
* Active and unsettled weather patter sets up over the area for next week. Daily chances of showers and storms with some our heaviest rainfall occurring on Wednesday.
* Multi day rainfall amounts from Sunday night to Friday afternoon will range between 3 to 4 inches
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.UPDATE... Issued at 847 PM EDT Sun Sep 21 2025
Convective activity has died off from the afternoon storms we had across the area. Nice to see some rain again over the region! Expect that trend to continue over the next several days, as in the discussion below. Convective allowing models still are showing a ramp up in precip chances again later tonight, as a 20-30 kt low- level jet develops across western KY. Convergence along this flow as well as some weak broad-scale lift should allow for this development. Have adjusted pops a little to account for slight changes in the latest runs of those models. Updated forecast products out shortly.
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.SHORT TERM /THROUGH THIS AFTERNOON/... Issued at 403 PM EDT Sun Sep 21 2025
Atmosphere has started to recover from the earlier round of showers and thunderstorms from the morning. Low-level lapse rapes have begun to steepen while mid-level lapse rates remain weak. A linear cluster of showers/storms stretch from Henderson, KY southeast towards Franklin, KY. These showers have been firing along a weak sfc trough with a little help from a weak LLJ over the area. These storms have had history of producing gusty winds of 30-35 mph. Hi- res models have had a hard time picking up on the development but did notice it picked up on this boundary. Should see the activity in the Louisville area close to 630pm and near Lexington around 830pm if they managed to hold together as they move to the northeast. We remain in a marginal risk for severe weather through the afternoon and overnight.
Once this wave moves through later this evening, models indicate we could see a bit of a lull in the activity, but still want to keep an isolated to scattered chance of a possible shower/storm. LLJ is expected to increase during the early morning hours over the area just before sunrise, out ahead of the approaching upper trough axis. Shower/storm chances start to increase during this time, with higher morning chances along and north of the Ohio River. Trough axis arrives and works across the CWA during the day tomorrow. A large swath of showers and storms look to develop near and north of the Ohio River with more scattered showers and storms the further south you go. SPC has the CWA once again in a Marginal Outlook for severe weather (1 out of 5). Moderate instability will be in place during the afternoon and evening as the trough axis moves through. Like today, mid-level lapse rates will remain low but effective shear looks to range between 20-30kts, allowing for better organization of any convection that develops tomorrow afternoon. Main threat will be strong gusty winds, lightning with some possible hail.
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.LONG TERM /TONIGHT THROUGH SUNDAY/... Issued at 403 PM EDT Sun Sep 21 2025
Weather through the long term looks to be active and unsettled as a series of disturbances will work through the Ohio Valley. We may get a brief break on Tuesday as the trough axis from Monday will works off to our south and east by Tuesday afternoon. An upper low looks to take shape over the Central Plains on Tuesday and then develop a sfc low over the Ohio Valley on Wednesday. while the deterministic models agree on the development of the sfc low, they still differ on timing and location. Either way weather will remain unsettled and wet as we go through the middle and end of the week. Sfc low will slowly work over the Ohio Valley and into the eastern Great Lakes during the day Thursday before weakening and lifting off to the northeast. Closed low looks to open up into a trough lingering over the Ohio Valley Thursday into Friday.
Much needed rain is expected to fall during this time with total rainfall amounts from Sunday night to Friday afternoon ranging from 3 to 4 inches. WPC does have central KY and southern IN in a slight risk for excessive rainfall on Wednesday as the sfc low deepens and works to our north. Thankfully all of this rainfall is spread out over the long term and should bring some relief to current drought conditions.
Temperatures will also be turning colder through the long term, starting out near normal around the low/mid 80s on Tuesday then falling into the mid 70s through the end of the week.
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.AVIATION /06Z TAFS THROUGH 12Z TUESDAY/... Issued at 139 AM EDT Mon Sep 22 2025
A weak LLJ is developing over the region and has kept showers and storms over western Kentucky this morning. These showers and storms are expected to slowly move NE into central Kentucky and southern Indiana. Have some TEMPO groups in for terminals west of I-65 through sunrise. Once rain begins, we will see multiple rounds of showers and storms through the region, lasting most of the day and into the overnight. Have highlighted with tempo and prob30 groups the best timing for TSRA right now. In the mid-morning, guidance shows lower CIGs to MVFR conditions, have included this as well. In the overnight, showers and storms are expected to continue, especially over the northern terminals.
Some storms may become strong and gusty winds and small hail will be possible.
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.LMK WATCHES/WARNINGS/ADVISORIES... KY...None. IN...None.
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UPDATE...RJS SHORT TERM...BTN LONG TERM...BTN AVIATION...SRW
NWS LMK Office Area Forecast Discussion