textproduct: Louisville

KEY MESSAGES

* Additional round of showers and thunderstorms expected later this afternoon and this evening. Heavy rainfall and small hail are the primary threats. An isolated spin up over our far western and southwestern areas can't be ruled out.

* Active weather pattern will bring additional rainfall to the area Thursday through Saturday.

* The late weekend and into early next week will see drier conditions.

SHORT TERM /THROUGH TONIGHT/

Issued at 332 PM EST Tue Nov 18 2025

Surface analysis this afternoon shows a warm frontal boundary stretching along the I-64 corridor. This warm front is producing an impressive temperature gradient across Kentucky with lower 40s over the northern Bluegrass region and into northeast Kentucky, while areas along the KY/TN border are in the lower 70s...a 40+ degree temperature gradient. For much of the afternoon, we have been watching several band of showers and storms move east across the region. Much of this activity has been elevated in nature given a strong inversion seen on model soundings and ACARS soundings out of KSDF. Currently, an area of convection continues from Grayson county northeastward through the Lexington metro area. This activity is sub-severe and is not expected to strengthen as it continues eastward.

To our west, an area of surface low pressure was located just east of St. Louis. Aloft, a shortwave trough axis and small scale mid- level jet streak will push eastward into the middle Ohio Valley this afternoon and evening. This wave and jet max will weaken with time and this will also allow the surface low to gradually weaken as it moves eastward along/just north of the I-64 corridor. As the afternoon wears on, additional convection is likely to redevelop across portions of southern IL/SW IN/W KY in the pre-frontal trough axis. This activity should slide southeastward this evening while weakening. There remains the possibility that a narrow corridor of instability still could develop, but it looks increasingly likely that this corridor of instability will stay to our west and southwest. Most likely area of strong/severe storms is likely to be in the SE MO/far western KY area where sufficient clearing and destabilization has taken place. Further east across southern IN and central KY, ongoing cloud cover and continued convection is likely to keep the warm front nearly stationary with surface based instability remaining large limited. Most storms across our region are likely to remain elevated in nature and poise a threat of heavy rainfall and perhaps some small hail in the strongest cores. By 19/2-3Z much of the convection should be on the wane as large scale forcing diminishes and the boundary layer grows increasingly stable.

Surface cold front is forecast to push through during the overnight hours with winds shifting to the northwest. However, low-level inversion will remain and keep moisture trapped beneath, so plenty of low stratus and fog/mist/drizzle will linger into the overnight, resulting in reductions in visibility for Wednesday morning. Lows tonight will remain mild with readings in the lower 40s across the far north with lower-mid 50s elsewhere.

For Wednesday, mostly cloudy skies are expected as shortwave ridging builds into the region from the west. Highs look to warm into the 55-60 degree range over southern IN and the northern half of Kentucky. Highs in the lower-mid 60s are expected across southern Kentucky.

LONG TERM /WEDNESDAY THROUGH TUESDAY/

Issued at 332 PM EST Tue Nov 18 2025

Thursday through Saturday Night...

An unsettled weather pattern is expected through this portion of the forecast period as broad west-southwest confluent flow aloft sets up across the Plains and into the Ohio Valley. A large upper level low will be found across the southwest portion of the CONUS with smaller scale perturbations shearing off an moving east-northeast. A good flow of moisture will be advected northward into the region which will bring widespread rain showers to the region. Model soundings do not show much in the way of surface based instability here. Additionally, the wave aloft doesn't have much amplitude, so the risk of significant synoptic scale lift does not look supportive enough to generate deep convection. Nonetheless, steepening lapse rates aloft may provided enough instability to produce some rumbles of thunder across the region. Rainfall amounts of 1-2 inches continue to look reasonable here, though some locally higher amounts will be possible. Overall, the flood threat looks very minimal here.

Highs through the period will likely feature a gradient of sorts, with lower 60s across southern Indiana and much of the northern half of Kentucky. Across southern Kentucky, highs in the upper 60s look attainable. Overnight lows will generally be in the 50s, though they should cool a bit Saturday night into the upper 30s/lower 40s.

Sunday through Tuesday...

Moving into the late weekend, a split flow pattern looks to emerge aloft as there will be an upper level cut off low over the southwestern US with mainly zonal/confluent flow downstream across MO and into KY. This should result in a rather dry forecast for Sunday and Monday. By Tuesday, the upper level low will likely move into the Plains with warm advection type showers gradually overspreading the region. Generally seasonal temperatures are expected here with highs in the upper 50s to around 60 with overnight lows in the 40s.

Extended Forecast Discussion...

An interesting period of weather looks possible as we head toward the Thanksgiving holidays. A decent mid-latitude cyclone looks to pass to our west/northwest in the late Tuesday night and Wednesday time frame. Models show plentiful moisture and shear for widespread showers and perhaps some thunderstorms. However, the usual uncertainties on instability remain and will not be resolvable until early next week. The GFS/GEM are the quickest bringing this system through, while the Euro is slightly slower, by 12-18 hours. This system will then likely usher in a much colder airmass as we head into Thanksgiving Day.

Since our last extended discussion, several iterations of signal analysis has been completed. While earlier signal analysis had a weak signal centered around 11/28, the latest iterations have a much stronger signal for the same period. Taking into account the possibility of the upper pattern becoming a bit more amplified, this signal may pass through the region in the 11/28-11/30th time frame. All three dynamical models (GEM/Euro/GFS) are hinting at the emergence of a southern stream system in this time frame which could bring wintry weather to the region late Thursday and into Friday.

AVIATION /18Z TAFS THROUGH 00Z THURSDAY/

Issued at 1223 PM EST Tue Nov 18 2025

Surface warm front is along and just north of I-64 this afternoon. A SW-NE band of showers and embedded thunderstorms is working across central Kentucky at this time and will primarily affect LEX/RGA/BWG this afternoon. Gusty winds will be seen across southern KY including KBWG. Additional convective redevelopment is expected across SW IN and western KY this afternoon and will push eastward across the region late this afternoon and this evening. Surface cold front will then plow through the region ending showers/storms from NW to SE. Behind the front, IFR to LIFR cigs will build down across the region. A good signal of fog is showing for KLEX/KRGA later tonight, though we'll continue to watch for that fog signal in the BWG area as well.

LMK WATCHES/WARNINGS/ADVISORIES

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