textproduct: Louisville

KEY MESSAGES

* Quiet weather is expected through tonight across the region, though patchy fog is possible (20% chance) early this morning.

* Shower and storm chances will return by late Thursday and continue through Saturday night. Excessive rainfall is likely across southern Indiana and portions of northern Kentucky. If current forecasts hold, flood watches will be need in subsequent forecasts.

* Early next week the upper level pattern will shift allowing summertime heat and humidity to build across the region. Temperatures will warm to above normal with oppressive humidity and heat indices approaching 100 degrees by Tuesday/Wednesday.

SHORT TERM /THROUGH TONIGHT/

Issued at 328 AM EDT Wed Jun 24 2026

Under the influence of surface high pressure, dry and mild conditions will continue another day across central KY and southern IN, with forecast highs in the low 80s and partly cloudy skies. As that high shifts east tonight, light and variable winds will switch to southerly to gradually advect a more seasonably humid airmass into the region. Even so, temperatures should drop off quickly during the evening to favor overnight lows in the low-mid 60s for most of the area.

Fog has yet to be observed at any central KY/southern IN observation site early this morning, though dew point depressions are quite shallow (2-4 degF) in rural and low-lying areas where light winds have allowed cool air to settle. While scattered cirrus should offset radiational losses through dawn, pockets of 10-20% HREF probabilities for sub 1/2 mile visibilities has led us to cautiously maintain a mention of patchy fog through 9am EDT/8am CDT.

LONG TERM /THURSDAY THROUGH TUESDAY/

Issued at 328 AM EDT Wed Jun 24 2026

Thursday through Sunday Night...

Fairly zonal flow aloft will be seen across the central and eastern US to start off this period of the forecast. A mid-level shortwave trough axis is forecast to push eastward across the Midwest and into the Great Lakes on Thursday. Associated surface front over the Great Lakes will drop southward and into central IL/IN/OH by late Thursday. The front will continue to drop southward and begin to stall out north of the Ohio River by Friday and into Saturday. This front will become a focus for additional convective development through the weekend.

Thursday will likely start off dry across the region. A southwest flow will bring increasing moisture and warmer air into the region. By Thursday night, we'll see PWAT values in the 1.9-2 inch range. Highs will push into the middle 80s (83-88) in the afternoon. During the heating of the day we could see some scattered afternoon convection fire across portions of southern IN and into the northern half of Kentucky. Southern KY looks to remain generally dry as a mid-level capping will likely supress convection. Some strong storms are possible on Thursday. However, overall confidence in severe risk is low given that the combination of higher shear and instability will be offset a bit. Model soundings would suggest that damaging winds would be the primary weather hazard. The low- level jet is expected to increase across western KY into southern IL/southwest IN Thursday night which leads us to believe that we'll see a gradual backbuilding of convection with time. The placement of this convection continues to vary within the models, however, the multi-model consensus/ensemble mean is more suggestive that this band may set up along/north of the I-64 corridor.

By Friday, a secondary shortwave trough axis will move from the Mid- MO valley through the Ohio Valley on Friday. This feature will bring another round of heavy rain producing convection to the region, targeting southern Indiana and portions of northern Kentucky. Severe potential on Friday will be conditional on how much instability can be generated. In systems like this, quite a bit of convective cloud debris may inhibit strong heating. The main threat on Friday continues to be heavy rainfall and training of convection over the same areas. WPC has highlighted areas along and north of the I-64 corridor in a slight risk of excessive precipitation here. High temperatures Friday will likely feature a gradient with upper 70s/lower 80s over southern IN and northern KY with mid-upper 80s across southern KY.

On Saturday, the quasi-stationary boundary may settle a bit more south into Kentucky as ridging starts to build out to our west. Current thinking is that the boundary may stall out along the WK/BG Parkway. With additional shortwave perturbations moving through in the zonal flow aloft, episodic bouts of convection with heavy rainfall will likely target much of central Kentucky through Saturday night. The WPC new day 4 will feature a slight risk of excessive rainfall across much of central and eastern KY. Highs on Saturday will be in the lower 80s with overnight lows in the upper 60s/lower 70s.

By Sunday, we'll start to see the upper level pattern shift a bit with stronger troughing developing across the western US. This expected shift in the pattern has been anticipated as the mid-June Pacific Jet extension quickly retreats back to the west. This will allow stronger troughing to develop across the western US while more significant ridging will attempt to build in the central US and perhaps more eastward into the Ohio Valley. Quasi-stationary boundary over KY will likely lift northward in response to the increasing height rises over the Mid-MS valley region. We'll likely some additional convection across the region on Sunday, but that activity should start to lift back to the north and east by late Sunday resulting in a drier pattern.

QPF for the Thursday through Sunday night period will likely be excessive across our region. Current forecasts would suggests widespread 3-4 inch rainfall amounts across southern Indiana and into portions of northern KY. Locally higher amounts will be possible where training of storms occur. As forecast confidence increases, a Flood Watch for southern Indiana and portions of northern KY will likely be needed for the late week and into the weekend.

Monday through Wednesday...

Moving into next week, significant troughing will continue over the western CONUS with downstream ridging over the mid-MS valley region. The ridge axis will be centered west of us on Monday and the ridge will likely build eastward into the Ohio Valley on Tuesday and Wednesday. This will bring a much drier pattern to the region along with increasing temperatures. Current temperature guidance is surging temperatures into the low-mid 90s early next week. This is likely too aggressive across southern Indiana and the northern half of Kentucky where excessive rainfall has fallen in the last two weeks. We're likely going to see the global model's soil moisture dry out too quick. Additionally, the above normal rainfall has left the area with lush/green vegetation which will likely limit higher heating until we can dry out a bit more. It's possible that the core of the heat may be centered down across southern KY where rainfall has been less over the last couple of weeks. Probably of more concern is that rather than a massive heat wave, we'll likely see a period of oppressive humidity along with slightly above normal temperatures. The combination of higher dewpoints and temperatures could allow us to approach heat advisory criteria over portions of southern KY by Tue/Wed, with little relief at night.

AVIATION /12Z TAFS THROUGH 18Z THURSDAY/

Issued at 650 AM EDT Wed Jun 24 2026

VFR conditions are expected to prevail throughout the forecast period at all terminals. Surface high pressure will shift east of the region this evening, causing generally light and fickle winds to return from the south.

LMK WATCHES/WARNINGS/ADVISORIES

KY...None. IN...None.