textproduct: Louisville

KEY MESSAGES

* Scattered showers and thunderstorms continue bringing threats of isolated flash flooding, lightning, and gusty winds this afternoon and evening, and again on Wednesday afternoon and evening.

* Rounds of showers and thunderstorms are expected late week through the weekend along a slow moving frontal boundary. Flash Flooding, including potential for significant flash flooding, could develop late week through the weekend with repeated rounds of heavy rain.

* Additional threats of gusty to damaging wind could develop with complexes of thunderstorms moving into the area. Overall confidence is low with regard to timing of these specific threats.

SHORT TERM /THROUGH WEDNESDAY NIGHT/

Issued at 257 PM EDT Tue Jul 7 2026

Cutoff low continues to meander near the Mississippi and Ohio River confluence, and the associated PWAT airmass is up around 2" through the column. Scattered showers and storms have developed in this moist and moderately unstable (2000 J/KG of ML CAPE) airmass, however there isn't a lot of deep layer shear as has been the case the past several days. The end result continues to be slow-moving heavy rain producers that develop on remnant outflow from previous storms, and the collapse rather quickly. Basin average QPF amounts won't be all that impressive, however localized amounts close to 2 inches are possible in fairly short periods of time. A few Flash Flood instances may arise, and scattered Flood Advisories seem probable through the diurnal peak late afternoon through the evening.

Convection is expected to diminish later this evening with a quiet overnight in store. There will likely be patchy fog development once again, especially in area that see swaths of heavier rain today. After highs in the mid to upper 80s today, mild low temps only in the upper 60s and low 70s are expected tonight.

The pesky closed upper low will start to get picked up by the prevailing westerlies tomorrow, and will likely transition to an open shortwave as it slowly slides through the area. The morning will likely start off quiet, however initiation of scattered showers and storms is expected by late morning into the afternoon once convective temps are reached. Another rinse/repeat day with diurnally driven slow-moving showers and storms capable of locally heavy rainfall. A few Flash Flood Warnings and/or a handful of Flood Advisories continue to be likely. Temps will be similar to today in the mid to upper 80s.

LONG TERM /THURSDAY THROUGH MONDAY/

Issued at 257 PM EDT Tue Jul 7 2026

Thursday - Sunday...

The closed upper low that had plagued the area through mid week will finally get picked up by the prevailing westerlies by Thursday. This feature will move east as an open wave, with more of a subsident airmass in place behind the departing trough axis. As a result, we have lower chances for showers and storms, along with lighter expected rainfall amounts through the day. This could be the one day we don't get a bunch of diurnally driven pulse storms in the afternoon and evening, and more just a few lingering showers earlier in the day. Will be looking for highs in the mid to upper 80s.

By Thursday night, focus will shift upstream as a shortwave embedded within the zonal flow aloft ejects toward our region. This feature is likely to trigger some sort of convective complex upstream during peak heating, and then work toward our area into the overnight. Depending on how much of a cold pool this gets going, and time of arrival it seems feasible that a wind threat could accompany any complex that survives into our area late Thursday night Friday morning. Overall, the deep layer shear profile isn't too impressive, and storms would likely be arriving during the diurnal minimum. However, all you need is a good cold pool pushing into some lingering MU CAPE, which we will likely have, and marginally sufficient deep layer shear contributing to MCS maintenance. Will carry pretty widespread pops in the late Thursday night/early Friday morning time frame. Could be some concern with localized flooding given wet antecedent conditions ahead of this wave, and PWATs potentially surging over 2" through the column with this wave. One thing that could mitigate the early flood threat, however, would be the likely progressive nature of the complex as it moves through the area. At this very least, this wave may set the stage for higher flooding concerns with the following waves expected into the weekend.

A concerning setup looks to continue into the weekend as progressive zonal flow aloft persists over our area, while a slow moving surface front sinks into our region and stalls. This W-E oriented boundary will be parallel to the upper flow, and with multiple moisture-laden shortwaves riding along it, we'll expected repeated rounds of shower and storms through Saturday night. The final wave sometime Saturday into early Sunday could be the most potent, and if we have already seen multiple rounds of showers and storms we could be set up for some more concerning flood potential by this time.

Ensemble plumes through the weekend show most clustering around 2-4" of rain for basin average amounts, however 07/00z deterministic runs show swaths of 4-6" across the area. Given the setup with moderate instability, periods of high PWATs near 2" through the column, and tall/skinny CAPE combined with high freezing levels (14-15K feet), think localized amounts could potentially be higher. Especially with the W-E training of multiple waves over the same area. Will be ramping up messaging today, and may have to start mentioning potential for significant localized flooding as a possibility through the weekend.

Will mention one scenario that could help us dodge a round or two through the weekend. If we can get one of the upstream MCS to really blast through our region, it could potentially set up the convectively reinforced boundary farther south. Of course, we would likely have to pay the price with a higher damaging wind threat if that did happen, so I guess it could be a "pick your poison" type of deal.

Sunday Night - Tuesday...

Interesting pattern change as we go into early next week. Strong upper riding characterized by H5 heights around 600 dam will build into the central CONUS, with eastern fringes of influence into our area. This should bring us into a drier/warmer pattern with the previous frontal boundary sinking well south. The setup transitions to a Rex Block pattern through at least mid week, and should give us some relief from the relentless rain for a little bit, however at the expense of increasing temps back toward the 90s. This will be a notable change after weekend temps more in the lower and mid 80s.

AVIATION /18Z TAFS THROUGH 00Z THURSDAY/

Issued at 151 PM EDT Tue Jul 7 2026

Things are VFR at the TAF sites for the moment, however we will run the risk of scattered showers and storm through the rest of the afternoon and evening, much like previous recent days. Brief heavy rainfall reducing vis to low MVFR or IFR is possible, along with some gusty winds. Outside of storms, surface winds will be light and variable this afternoon, and then could become erratic later this afternoon and evening once thunderstorm outflows get bouncing around. Low confidence on any wind forecast, at least through sunset.

Tonight, convection will diminish however we'll likely have favorable conditions for some fog development. Hinted at this with some reduced vis in the pre-dawn hours. Otherwise, look for Wednesday morning to start off dry with visibilities improving quickly after sunset.

LMK WATCHES/WARNINGS/ADVISORIES

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