textproduct: Louisville

KEY MESSAGES

* Multiple waves of thunderstorms and showers are expected to produce widespread rainfall amounts of 1-2 inches with localized pockets of 3-4+ inches resulting in an elevated risk for flash flooding to potentially significant flash flooding today through Saturday evening.

* Flood watch remains in effect for until Saturday evening.

* Some thunderstorms have the potential to be strong with an isolated severe threat tonight into Saturday morning.

* Could see seasonable summertime temperatures for Sunday into the first half of the week with daily afternoon and evening chances of scattered showers and thunderstorms.

SHORT TERM /THROUGH SATURDAY NIGHT/

Issued at 243 AM EDT Fri Jul 10 2026

The first wave of showers and thunderstorms from this evening that was associated with the severe threat have dissipated and are moving into eastern KY. Our attention turns to the second round currently moving over the IL-KY-MO Tripiont and associated with the leading edge of an increasing LLJ that is expected to work from western KY eastward along the KY/TN border into south central KY by daybreak this morning. This 850 jet continues to pump in rich tropical moisture with 2.4" PWAT values located over the Tripoint and spreading eastward where we have 2-2.2" PWAT values along and west of I-65. As this complex works eastward, so will the 2"+ values. Given that the current instability gradient current works stretches from the Missouri Bootheel southeast towards Memphis, TN current thinking is the bulk of this complex will dive south chasing the better instability but also expect some convection to develop with the approaching LLJ across southern KY with just scattered activity north across the OH River and northern KY. The heaviest precipitation likely just clips our far southwest corner of the CWA with an additional half inch to an inch, but any storm we get will have the potential to put down an inch or two in an hour due to our high PWAT values.

Once this second wave comes to an end and moves out of the area by late morning to around midday we should see another lull in activity outside of a few isolated to scattered showers and storms in the afternoon and evening. we then turn our attention to the third wave that will arrive overnight tonight into early Saturday morning. Another shortwave trough will work out of the central Plains Friday afternoon and work along a sfc boundary that will drop south and stall near the Ohio River later tonight into early Saturday morning. A strengthening LLJ will continue to feed moisture rich air into the area right along and south of the boundary with PWAT values once again climbing to between 2.2-2.4" this time across western and central KY late tonight into early Saturday morning. Probabilistic guidance was starting to show agreement of where the heaviest and highest amounts of rainfall could fall stretching from Evansville, IN to Bowling Green, KY or along the 165 corridor where the probability of receiving 2 inches or more of rainfall was around 40- 50 percent. This is generally the same location that saw heavy rainfall nearly 2 weeks ago around the end of June, so soils are still saturated and in some cases flooding is still ongoing. If we see these potentially high rainfall amounts of 3 to 4+ we could be looking at another significant flash flooding event early Saturday morning. While confidence is growing on location and timing of where the heaviest of rainfall could fall, there was still around a 10-20 percent probability of over 2 inches to fall for the rest of the CWA.

Current timing is the storms and heavy rain early Saturday morning will be out of the area by late morning or midday Saturday. As the sfc boundary starts to push south as the shortwave trough moves off to the east, scattered showers and thunderstorms could form in the late afternoon and evening on Saturday with the strongest activity moving south into TN along with the sfc boundary.

While flash flooding remains the main threat for today into the start of the weekend. There is a marginal risk for severe storms later today into tonight with gusty locally damaging winds the main threat. Unlike last night's storm threat, this activity will be arriving late at night and early Saturday morning limiting the amount of energy available. But with a strong LLJ and water loading due to the high 2"+ PWAT values this makes sense and agree with SPC placement of the marginal.

LONG TERM /SUNDAY THROUGH THURSDAY/

Issued at 243 AM EDT Fri Jul 10 2026

The end of the weekend into the start of next week is not looking as dry as it was just 24 hours ago. Strong ridging will increase over the central US extending as far north as the Dakotas on Sunday. A cutoff low is expected to retrograde back to the west and undercut the ridging as the top of the ridge builds and pushes eastward over the Upper Midwest and Great Lakes. The cutoff low will slowly track westward over KY and TN Monday and Tuesday before working over the Central Plains and Rockies on Wednesday. Ridging will then reamplify over the SE CONUS and tilt back towards the northwest and across the Ohio Valley towards the end of the week.

What this could mean for our forecast is unsettled weather with daily afternoon shower and thunderstorm chances with this activity producing heavy rainfall as PWAT values linger close to 2". It will really depend on how far south the stall sfc boundary from over the weekend gets Sunday and Monday. Current forecast trends is this boundary stalls somewhere over TN and becomes more of an inverted sfc trough as the cut off low moves over the region Monday and Tuesday. If it goes further south our forecast could turn out drier.

Once the cutoff low moves to the west and the upper ridging reasserts itself from the SE the boundary will become a warm front allow for typical summer heat and humidity with highs in the upper 80s to near 90 and dew points in the low/mid 70s. Confidence right now is not very high and will continue to have to update as we start to see more agreement and possibly how the different waves of convection today and Saturday impact the sfc boundary placement.

AVIATION /12Z TAFS THROUGH 18Z SATURDAY/

Issued at 721 AM EDT Fri Jul 10 2026

We will see rain start to dissipate but hold on to MVFR flight categories for part of the morning. Should see a break with VFR flight categories returning and even a break from the showers and storms. It is very likely we stay mainly dry through the day and potentially into the evening. The issue is timing the next wave or potentially multiple waves overnight into Saturday morning. Confidence in the forecast really drops after 00z as there are too many timing issues with the next couple waves of showers and storms.

LMK WATCHES/WARNINGS/ADVISORIES

KY...Flood Watch through late Saturday night for KYZ023>043-045>049- 053>057-061>067-070>078-081-082. IN...Flood Watch through late Saturday night for INZ076>079-083-084- 089>092.