textproduct: Louisville

KEY MESSAGES

* Dry weather continues for the weekend and into next week. Temperatures begin to increase over the weekend and especially into next week, with low to mid-90s possible.

* Major Heat Risk possible next week due to the multi-day duration of hot temperatures and little overnight relief. Anyone without effective cooling or adequate hydration will be susceptible to heat illness.

* A few shower and storm chances may return by late week, but current confidence is low.

SHORT TERM /THROUGH TONIGHT/

Issued at 306 AM EDT Sat Aug 29 2026

Mostly clear morning with some valley fog showing up on satellite imagery. Any fog this morning will burn off shortly after sunrise. We'll have yet another dry and mostly sunny day as sfc high pressure over the eastern US expands back to the Midwest. Temps today will reach the upper 80s and lower 90s, with the best chance for those hotter temps across south-central KY. Dry weather continues tonight with clear skycover and temps in the upper 60s.

LONG TERM /SUNDAY THROUGH FRIDAY/

Issued at 306 AM EDT Sat Aug 29 2026

===== Heat Builds Next Week =====

The prolonged dry streak continues for Sunday and into early next week as sfc high pressure remains anchored over the mid-Atlantic region and upper ridging builds over the central US. The main focus for this time period will be the increasing heat by early next week, where there is growing confidence in daily high temps solidly in the 90s. Temps on Sunday are forecast to reach the upper 80s to low 90s, but each subsequent day could be slightly hotter by Wednesday with potential for mid to upper 90s. Dewpoints will mainly be in the upper 60s to lower 70s over this time, which fortunately will help keep our heat indices from becoming oppressive. While it will be muggy, heat index values are mainly expected to range from the upper 90s to low 100s. The 100-member LREF indicates that there is less than a 10% chance for max heat index values over 100 for Sunday and Monday, but those chances start to increase on Monday and Tuesday, and peak on Wednesday with roughly a 25-55% chance for most. In addition to the afternoon heat, there will likely be little relief during the nighttime hours, with overnight lows in the 70s each night.

Despite dewpoints not being very high, the combination of hot temperatures, little overnight relief, and the prolonged duration of heat will likely lead to major heat risk. Major heat risk means that anyone without effective cooling or hydration will be prone to heat illness. Probabilities vary by location, but there is roughly a 55% chance or higher for major heat risk by Tuesday of next week across the area. That probability increases to at least a 70% chance by Wednesday. Three or more consecutive days of major heat risk will trigger an extreme heat risk, which essentially means the entire population could be susceptible to heat illness if precautions are not taken, and there could be increased impact to health services. Based off our forecast temps, we have a generalized 25% chance of extreme heat risk by Wednesday, though the urban areas are closer to 50%.

While we may not reach criteria heat indices next week, the duration of this event and subsequent impacts should be considered in making any Heat Advisory decisions. No plans on this yet, but will need to consider in following forecast packages.

We remain dry through Wednesday, with our next precip chances not until Thursday. There is lower confidence toward the end of the week with temps and precip, but generally expect the 90 degree temps to continue through the end of next week.

AVIATION /12Z TAFS THROUGH 18Z SUNDAY/

Issued at 647 AM EDT Sat Aug 29 2026

Some patchy fog has developed across the region this morning, and has impacted vis at RGA and HNB so far. On and off reduced vis will continue for the start of the forecast period, but expect steady VFR conditions for the rest of the period once the morning fog burns off. Should see a mix of mid and high level clouds again today, with light winds from the east.

LMK WATCHES/WARNINGS/ADVISORIES

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