textproduct: Louisville

KEY MESSAGES

* Another round of showers and storms is possible late Sunday with an MCV moving through the region. Any storms that develop will have the capability of producing damaging winds and brief heavy rainfall.

* A reprieve from the hot and humid weather, as well as showers and storms, comes Monday evening once the cold front departs to the south. Showers and storms arrive again for the mid and late week time frame, however temperatures should be slightly below normal for this time of year.

SHORT TERM /THROUGH MONDAY NIGHT/

Issued at 229 PM EDT Sun Aug 16 2026

Currently, a MCV is tacking eastward from the Central Plains into southern Iowa and northern Missouri. This system is expected to continue eastward and move through southern IN bringing showers storms to the Ohio Valley late tonight. Additionally, a frontal boundary will continue to sink SE through today and move through the area tonight.

There is a slight chance (20-30%) of isolated storms to develop this evening ahead of the boundary, mainly in the northern half of the forecast area. There is ample amounts of instability for any storms to develop with an initiation trigger. Wind shear is marginal within central KY, however there is an axis of 30-40kt shear in southern IN due to a low level jet. With DCAPE near 1500 J/kg and PWAT values around 2", any storms that do develop could have the potential for severe winds and even microbursts.

Once the MCV moves into southern IN overnight, a cluster of storms will track through the northern part of the CWA. SPC severe weather outlook current has the area in a slight risk, specifically for damaging winds. Confidence in timing has been on the lower side, however HiRes models are finally somewhat in agreeance with the system moving through. Storms will move in from the east around 1AM EDT and makes its way to the Blue Grass between 4-6AM EDT. Instability will start to erode with sunset, however 1500J/kg of SBCAPE is still expected to hold on ahead of the system. The highest amounts of wind shear values seem to be behind the system as a shortwave disturbance moves into the region. The main threat with these storms will be strong to damaging winds, while a localized flash flooding threat is not out of the question.

The rain chances are done yet as there is a chances for some isolated to scattered showers and storms to develop Monday afternoon. At this time, there are no severe threats expected though a rumble of thunder could still be possible. Aside from rain chances, a relief in temperatures is expected starting Monday with highs in the in the mid to upper 80s. Dewpoints are expected to still be in the mid to low 70s, but will start to take a dip Monday evening for a much nicer Tuesday.

LONG TERM /TUESDAY THROUGH SATURDAY/

Issued at 229 PM EDT Sun Aug 16 2026

Tuesday - Wednesday Afternoon...

The upper pattern will feature more of a zonal flow look as we move into mid week, thanks to a flattened upper ridge over the southern CONUS. Overall, this upper flow pattern looks to be void of any notable shortwave activity, and with high pressure in place at the surface this should be a dry stretch for us. Should see a good amount of sunshine on Tuesday, however temperatures will be overall cooler from the recent pattern, generally ranging between 85 to 90 degrees. Lows will also feel more comfortable in the mid and upper 60s.

The bulk of daylight hours on Wednesday should be dry, however we'll have to focus on timing of some shower and storm chances approaching from the NW as a weak frontal boundary trailing from an eastern Canada system drags toward the Ohio River Valley. We'll continue to carry some shower/storm chances across southern IN by Wednesday afternoon to account for this. Ahead of any showers or storms, temps are expected to warm to the upper 80s and low 90s across central and southern KY. Southern IN and northern KY will likely be confined more to the mid and upper 80s.

Wednesday Evening - Saturday...

Could have a fairly interesting setup for later Wednesday evening into Thursday as the aforementioned front likely makes its way down, or close to our region. In addition, models generally agree this timing could be accompanied by the arrival of a shortwave embedded in the digging eastern CONUS trough. The two features could be the catalyst for fairly good coverage of showers and storms later Wednesday evening into Thursday. It does appear that some decent deep layer shear will be present thanks to the shortwave enhancement, especially across our northern CWA. Tough to tell whether it will overlap with the best instability, as placement of the surface front could push things too far south to line up with the best shear. Bottom line, there could be a chance for some stronger storms here, but too early to tell given uncertainty in exact placement of features.

Troughing across the eastern CONUS downstream of amplified upper ridging across the western CONUS will be the pattern going into the weekend. A couple of shortwaves embedded in the parent trough could continue to rotate through the region going through Friday and Saturday, potentially triggering additional showers and storms. This will also keep temps a bit below normal for this time of year in the low and mid 80s.

Saturday Night - Sunday...

Looks like the upper trough axis might push east by Sunday, leading to a drier pattern to end the weekend. Temps will likely continue to run just below normal in the low and mid 80s.

AVIATION /18Z TAFS THROUGH 00Z TUESDAY/

Issued at 112 PM EDT Sun Aug 16 2026

VFR conditions will continue through this afternoon before showers and storms move back into the area. Late this evening into the overnight hours a weakening MCV will track over southern IN. Strong to severe storms are expected between 04z-14z as it moves eastward. PROB30 groups have been added to all sites, except BWG, for possible storms with gusty winds. After the rain moves out, winds will primarily be WNW with ceilings hovering around 5kft. A brief period of MVFR ceiling could be possible tomorrow afternoon but confidence is lower in that occurring.

LMK WATCHES/WARNINGS/ADVISORIES

KY...Heat Advisory until 9 PM EDT /8 PM CDT/ this evening for KYZ023>031-034-038-039-045-046-053-054-061>065-070>078- 081-082. IN...Heat Advisory until 9 PM EDT /8 PM CDT/ this evening for INZ076>078-083-084-089>092.