textproduct: Louisville

KEY MESSAGES

* Flood Watch: Numerous to scattered areas of showers and thunderstorms along and north of the I-64 corridor over to the I- 65 corridor could produce another 1.5 to 2.5" of additional rainfall resulting in localized flash flooding.

* Dense Fog Potential: Clearing skies combined with recent rain and saturated ground could lead to the potential development of dense fog early Thursday morning.

* Below normal temperatures through the weekend into early next week as there remains high forecast uncertainty on precipitation chances for the end of the week and into the weekend.

SHORT TERM /THROUGH TONIGHT/

Issued at 629 AM EDT Wed May 27 2026

Flood Watch is in effect from 8am this until late tonight for locations along and north of the I-64 corridor and along and east of the I-65 corridor. Many places inside the watch received an inch to 2.5 inches of rainfall, if not more, on Tuesday. Additional showers and thunderstorm development later this afternoon and evening could potentially add an additional 1" to 2" inches of rainfall over already saturated ground.

While we may see a few isolated showers to a rumble of thunder and patchy drizzle through the remaining overnight and early morning hours, most will start the day dry and overcast. Sfc boundary will continue to slowly lift northward and is expected to stall out just north of our CWA along and south of I-70 over to I-74 across central IN into southwestern OH. South southwesterly flow will keep deep moisture in place over central KY and southern IN with PWAT values ranging 1.5" to 1.7" with the highest values of 1.8" to 2.0" right along the boundary and dewpoints once again in the upper 60s to near 70. Hi-res models appear to be in fairly good agreement setting up another deformation band of moderate to heavy showers and thunderstorms to our north stretching from about Vincennes, IN to Bloomington, IN over to Cincinnati OH along and south of the boundary tomorrow afternoon. We expect to see some breaks in the clouds as we go into the afternoon and evening. How much and how quickly these clouds break will determine a couple things. First, just how warm we will get in the afternoon and second, if we do get to warm up we will see an increase in available instability. This could allow for some isolated to a few scattered showers and storms to develop south of the main band of showers and storms to our north. While the threat of severe is much lower today than it was yesterday, these storms will have plenty of moisture for heavy to moderate rainfall. Eventually the main line of convection and rain will start to drift back to the south-southeast late this afternoon and evening. Depending on speed, how well this activity holds together and duration over a particular area some areas could pick up locally 1 to 2 inches of rainfall, potentially higher. WPC continues to maintain a Slight Risk for Excessive Rainfall over the Flood Watch area. Like today, it is possible we could see a couple of Flood Advisories as well as Flash Flood Warnings.

As we lose daytime heating and the boundary starts to move southward, the activity will diminish in the evening as drier air behind the boundary starts to move in from the north. Clouds are expected to clear and given all the rain we've had over the last several days there is a growing signal in the models that some dense fog is possible Thursday morning. This will need to be watched with each new run of the models as well as how much we are able to clear through the evening and overnight.

LONG TERM /THURSDAY THROUGH TUESDAY/

Issued at 629 AM EDT Wed May 27 2026

Thursday - Early Next Week...

A region of high pressure over the Great Lakes region will start to dip down into the Ohio Valley region on Thursday. This will bring a drier airmass and NE flow to the region. A moisture gradient will be centered through KY, with the highest concentration of moisture along the KY/TN border.

Calm winds and partial clearing on Thursday morning could bring patchy fog, especially given the surface moisture from this week's rain. If cloud cover remains persistent then fog could be limited to localized areas and valleys. As the frontal boundary pushes out of the area, lingering showers will be possible Thursday evening into Friday in the southern CWA with the remaining moisture aloft. Any showers that move through are expected to be light with QPF value around 0.25" over the several days. For the weekend, the high pressure settles in and brings clearing skies and dry weather. High temperatures for the weekend are expected to be in the upper 70s. A weak surface low with a boundary could pass through central KY on Monday, possibility bringing rain showers. However, there is low confidence in this due to the lack of agreement in guidance.

AVIATION /12Z TAFS THROUGH 18Z THURSDAY/

Issued at 731 AM EDT Wed May 27 2026

Main impacts today will be morning stratus producing periods of MVFR and even IFR with a few isolated showers but most if not all TAF sites should remain mostly dry. Clouds will mix and break towards the afternoon for VFR flight categories. A band of showers and thunderstorms are expected to form north of the area then start to drift back south-southeast late this afternoon and evening. This could bring a period of heavy rain and thunderstorms to the area especially for SDF and LEX. The other main concern could be the potential for dense fog development tomorrow morning.

LMK WATCHES/WARNINGS/ADVISORIES

KY...Flood Watch through late tonight for KYZ030>043-048-049-057. IN...Flood Watch through late tonight for INZ078-079-092.