739 FXUS63 KLMK 111111 AFDLMKArea Forecast Discussion National Weather Service Louisville KY 711 AM EDT Thu Sep 11 2025
.KEY MESSAGES...
* Continued mostly dry and abnormally warm through the weekend into early next week. Highs in the upper 80s to low 90s.
* Potential for rapid onset drought and enhanced fire weather conditions continues to increase for mid-to-late September.
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.SHORT TERM /THROUGH TONIGHT/... Issued at 353 AM EDT Thu Sep 11 2025
Weak shortwave trough continues to slowly work through southern KY into TN during the early morning with an isolated cluster of showers along the TN/KY border. This activity will continue to push southeast and out of the area before sunrise. Clearing across southern IN and north central KY has allowed for some very patchy fog to develop which will mix out as we go through the morning.
Upper ridging building out of the southern plains expands northward during the day as the shortwave trough continues to work eastward. Weak inverted sfc trough will be located across western KY, southern IL into southwest IN. This may be enough forcing to help fire off isolated pop up showers in the afternoon. Decided to go with a 10 percent PoP for the southern half of our CWA later this afternoon. With sfc high pressure to our north over Hudson Bay, most of the CWA will likely remain dry. With increasing heights thanks to the expanding upper ridge, temperatures continue to be warmer with highs ranging from mid/upper 80s to near 90 across our southwest.
Any activity should start to diminish with the loss of daytime heating as we go into the evening hours, skies will be mostly clear, winds will be light and lows will be in the mid/upper 50s to near 60. Patchy valley fog could once again form across the region.
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.LONG TERM /FRIDAY THROUGH WEDNESDAY/... Issued at 353 AM EDT Thu Sep 11 2025
Upper ridging will continue to expand northeastward from TX into the Ohio Valley and Great Lakes through the weekend and into early next week. Locked into this pattern, temperatures will continue to warm from the mid/upper 80s to near 90 on Friday to low 90s into the weekend and early next week. Return flow out of the south will remain limited as dewpoints stay mainly in the 50s through the weekend. With the unseasonably warm temperatures and lower dewpoints, combined with abnormally dry to even moderate drought conditions across central KY and southern IN, we will continue to see elevated fire weather concerns. With surface winds staying light, the concern of spreading is limited. With the prolonged dry weather expected through the extended forecast, the fire weather parameters will need to be monitored.
As for our next chance of precipitation, upper ridging looks to hold firm over the Ohio Valley and into the Great Lakes into the first half of next week. While a weak backdoor cold front is expected to drop southward Sunday night into Monday, the trend in the deterministic models is for this boundary to be moisture starved with very low PoPs associated with it.
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.AVIATION /12Z TAFS THROUGH 18Z FRIDAY/... Issued at 710 AM EDT Thu Sep 11 2025
Latest surface analysis reveals expansive high pressure centered over Ontario and spreading southward into the OH Valley, while current satellite shows mostly clear skies with a few areas of patchy fog. Several observations across southern Indiana and central KY are reporting LIFR to MVFR vis in fog, and expect this to continue until shortly after sunrise, especially at LEX, RGA, and HNB. Otherwise, VFR conditions will prevail for most of this TAF cycle, with scattered clouds this afternoon and a light northerly wind. Light fog will likely present itself again Friday morning at the same aforementioned TAF sites.
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.LMK WATCHES/WARNINGS/ADVISORIES... KY...None. IN...None.
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SHORT TERM...BTN LONG TERM...BTN AVIATION...CG
NWS LMK Office Area Forecast Discussion