textproduct: Louisville

KEY MESSAGES

* The remnants of Hurricane Isaias will bring widespread rainfall and gusty winds over the weekend. Most areas will receive between 0.50" and 1" of rainfall, though localized areas of 1-3 inches will be possible, especially east of I-65. Wind gusts of 25-35 mph are likely Saturday afternoon and evening, with isolated 40 mph gusts possible.

* Dry and warm weather expected for early-to-mid next week.

DISCUSSION

Issued at 301 PM EDT Fri Oct 9 2026

===== This Afternoon through Tonight ====

Warm and dry conditions will continue this afternoon and evening, with temperatures topping out in the low-to-mid 80s. RH values are in the 20s in many areas, and this very dry air mass will take time to overcome as tropical moisture associated with Isaias starts to work its way into the region late tonight into Saturday morning. For this evening into tonight, light east winds and increasing cloud cover will keep temperatures milder, with lows Saturday morning only falling into the upper 50s and low-to-mid 60s.

===== Remnants of Isaias Move Through This Weekend =====

The main weather story from the Gulf Coast to the Ohio Valley this weekend will be Hurricane Isaias, which should make landfall in the FL panhandle this evening. Isaias is expected to lift fairly quickly to the north late tonight into Saturday before turning to the northeast and moving across the TN valley on Sunday. Deep moisture advection downshear from the TC center will overspread from south to north late tonight and through the day on Saturday. PW values are expected to rise from 0.6-0.7" this afternoon to over 1.50" by tomorrow evening, exceeding the 90th percentile of climatology. While the outermost bands of Isaias will likely end up as virga as the column saturates, rain should begin to reach the surface during the morning hours across southern KY, with the shield of rain likely becoming more broken/showery as it encounters the drier atmosphere. Scattered showers are expected to continue north, overspreading most of the area during the afternoon and evening hours.

Winds will increase through the day tomorrow as a 50 kt 850 mb jet moves into the region. While increasing saturation and cloud cover should limit momentum transfer later in the day, the strengthening pressure gradient should be sufficient for sustained easterly winds of 10-20 mph, with wind gusts of 25-35 mph likely. While there are low (10-40%) chances for occasional 40+ mph wind gusts, the expected coverage of such gusts should be low enough that a wind advisory is not needed. The strongest winds and gusts are expected from mid- afternoon through a few hours after sunset, when increasing stability and weakening of the pressure/height gradient associated with Isaias will support easing winds.

During the evening hours on Saturday into Saturday night, hi-res guidance suggests that a few bands of heavier showers and a few thunderstorms should set up across the eastern half of the CWA thanks to convergence along the leading edge of the LLJ as well as a plume of a few hundred joules of MUCAPE moving into the area from the southeast. In these bands, heavier rainfall totals would be expected, with 12Z REFS 6-hr LPMM amounts of 1-2" forecast east of I- 65. It should be noted that current 6-hr flash flood guidance is 3+" across the entire CWA, so these rainfall amounts would not be expected to cause flooding issues.

During the day on Sunday, the actual sfc low center is expected to pivot across southern KY and TN, with lingering low-level moisture supporting scattered showers and perhaps a few rumbles of thunder. Clearing should take place Sunday afternoon from west to east across the region as drier air wraps in. Overall, event total rainfall amounts have decreased since the previous forecast, with area totals generally on the order of 0.50-1". The highest rainfall amounts are now more likely along the I-75 corridor, where 24-hr LPMM amounts of 1-2+" are more widespread. These rainfall amounts should ameliorate, but probably will not remove, ongoing drought conditions.

===== Next Week =====

After the remnant low pressure associated with Isaias clears the region to the east, upper level ridging and sfc high pressure is expected to set up over the south central and southeast US for the first half of the week. Fairly amplified troughing will set up in the intermountain west, with individual shortwaves riding up and over the ridge across the central CONUS through the first two-thirds of next week. Current medium-range guidance has a strong enough ridge over the region to keep most rain chances associated with the shortwave disturbances north of the area through Wednesday morning, though a low (20% chance) PoP will return for Wednesday and later into the week. Temperatures are expected to be unseasonably warm early next week as SW flow pushes highs into the low-to-mid 80s.

For Wednesday into the latter half of next week, the main forecast uncertainty centers around how the trough in the western CONUS evolves as it begins to eject to the east. There is relatively good agreement that an upper level wave and an associated cold front will push through the Ohio Valley, with spread in ensemble members on timing and strength of the system.

AVIATION /18Z TAFS THROUGH 00Z SUNDAY/

Issued at 211 PM EDT Fri Oct 9 2026

This afternoon into the overnight hours should have mostly easterly winds with speeds around 5-10 kts. High cloud cover is in place over the southern portion of the CWA and should continue to move into the rest of the CWA, with the Southern IN counties in a BKN upper-level deck by 3z at the latest. 6z tomorrow is where things start to get interesting - BWG and SDF see winds start to increase through 12z - gusts of 15 possible, but gusts increasing in frequency and strength from 12-18z for all KY terminals. Max wind gusts expected tomorrow are in the 30-35kt range, mainly focused 15-20z. These should be mostly easterly. Rain begins in the 12z mark for BWG, increasing in intensity near the 18z mark. Rain begins for SDF/LEX/RGA around the 17z mark, and will likely increase in intensity in later TAF periods. An embedded rumble of thunder can't be ruled out for BWG/RGA/LEX in tomorrow's TAFs but confidence is low. Tomorrow between 14z through end of rainfall will likely include a LLWS line for most airports around 2000 ft; this is just due to the difference in strength and direction between sfc level winds and the 850mb jet carrying the TC Isaias remnants.

LMK WATCHES/WARNINGS/ADVISORIES

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