textproduct: Louisville

KEY MESSAGES

* Widespread rain and scattered storms expected Tuesday. A few stronger storms could produce small hail and a brief spin-up tornado.

* Active weather pattern will bring multiples chances for rainfall Thursday through Saturday.

* This weekend through early next week continues to trend drier.

UPDATE

Issued at 859 PM EST Mon Nov 17 2025

Regional radar mosaic shows a cluster of storms moving across LSX and ILX CWAs this evening, which is located on the nose of the 850mb jet core and WAA regime. The sfc low is located over northeastern Kansas for now, with the warm front extending to the southeast and the cold front trailing to the south. We'll see the warm front swing northward tonight into southeast MO, amplifying our isentropic lift across KY and IN, and resulting in radar echoes spreading out across our forecast area during the early morning hours. We should remain dry before midnight, and perhaps longer into the night as model soundings indicate rather dry air below 800mb.

Overall forecast remains in good shape, with only some tweaks to the grids to blend in the 00z guidance.

SHORT TERM /THROUGH TUESDAY NIGHT/

Issued at 305 PM EST Mon Nov 17 2025

A low pressure system will approach the region in the overnight hours. Ahead of the warm front, isentropic lift will allow for some light to moderate showers to push into northern Kentucky and southern Indiana after midnight. We will see some weak elevated instability develop in the early morning, which could bring some rumbles of thunder before sunrise. Otherwise, broken to overcast clouds will move into the region and WAA will help to keep temperatures above freezing tonight. Low temperatures are expected to be in the mid-upper 30s over the Bluegrass and upper 30s to low 40s over the rest of the region.

On Tuesday, the shortwave trough will swing through the Ohio Valley. In the upper levels, the Lower Ohio Valley will be located beneath the left exit region. A 40-45kt LLJ will also move over the region. These features will work together to provide plenty of lift to the region. Due to the location of the surface low, the lower Ohio Valley, is expected to be within the warm sector of the system, where WAA will increase PWATs to near the 90th percentile for this time of year. Forecast soundings show about 65kts of 0-6km shear and 35kts of 0-3km shear, so there is plenty of shear to support organization. The only factor that is lacking is the instability. Looks like we will have about 500 J/kg of MUCAPE and could see some weak SBCAPE over the southwestern portion of the region. Given these parameters and features, we will see scattered storms and some may become strong to severe. Main threats would be hail and a brief spin- up tornado. These storms are most expected along the cold front late Tuesday afternoon through the evening. Expecting storms to push east of the region by about midnight.

Tuesday night into Wednesday morning, clouds look to stay around as the lower level trough does not move out of the region and the front stalls in the lower Ohio Valley. Wednesday morning, we will likely see fog and low stratus over most of the region.

LONG TERM /WEDNESDAY THROUGH MONDAY/

Issued at 305 PM EST Mon Nov 17 2025

Wednesday - Wednesday Night...

Broad upper ridging will move east over the region on Wednesday. However, the stalled front will remain over the region, keeping clouds and moisture. Weak WAA will help to increase temperatures into the upper 60s and low 70s over southern Kentucky. Where north of the stalled boundary will see highs in the low to mid 60s.

Thursday - Sunday...

On Thursday, flow aloft will weaken and become more zonal. Vorticity shedding from troughing over the desert SW will stream over the region, bringing another round of showers. The troughing over the desert SW will then break off and move east into the Ohio Valley by late Friday into Saturday morning. Continuous moisture transport and vorticity lobes will keep rain chances in the region through Friday.

By Friday and early Saturday, the trough will develop a low pressure system that will track into the Ohio Valley. This will allow the stalled front to lift as a warm front, before the cold front of the system pushes through. This will bring another chance for storms.

Behind this front, high pressure builds into region bringing drier conditions for the weekend and into early next week.

AVIATION /00Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 634 PM EST Mon Nov 17 2025

VFR conditions continue across the region this evening, though clouds will be increasing ahead of our next weather system. Light rain will spread west to east across the area overnight and especially early tomorrow morning, first at HNB and last at LEX/RGA. There could be some very marginal LLWS overnight, but not expected to be enough to include mention in TAFs at this time. Scattered showers will persist through much of tomorrow morning, with chances for -TSRA by the afternoon. Could have some brief vis reductions with any TS, though HNB is the only terminal forecast to have cigs drop into MVFR by tomorrow afternoon. Despite plenty of rain chances in the forecast period, terminals are expected to remain mostly VFR.

LMK WATCHES/WARNINGS/ADVISORIES

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