textproduct: Louisville

KEY MESSAGES

* Showers and thunderstorms expected Saturday morning, mainly for southern IN and north-central KY. Additional scattered storms are possible across south-central KY Saturday afternoon. There is a Marginal Risk for severe weather, with hail and wind as the main threat for any strong to severe storms.

* Temperatures are expected to warm into the mid 80s to low 90s this weekend into the beginning of next week. Some daily max temperature records could be challenged. * Tuesday and Wednesday, more showers and thunderstorms ahead of a cold front, dropping temperatures back to near normal.

UPDATE

Issued at 1039 PM EDT Fri May 15 2026

This evening, moisture is beginning to move into the Ohio Valley from the west with nighttime microphysics satellite imagery showing a large mass of mid- and high-level clouds located along and west of the Mississippi River. A few showers are even being observed across southeast MO and southern IL. This moisture gradient is also reflected in regional obs at this hour as sfc dewpoints range from the mid 40s across east central KY to the upper 50s and low 60s across far western KY.

For the rest of this evening and overnight, a 40-45 kt 850 mb jet will begin to nose into the region from the west-southwest, supporting warm advection and increased moisture around 3-5k ft AGL. With a couple subtle mid-level shortwaves expected to approach the area early Saturday morning, the combination of low-level warm advection and neutral/slight negative upper-level height tendencies should lead to steepening mid-level lapse rates and increasing elevated instability. By around sunrise Saturday, hi-res progs show up to 2000-2500 J/kg MUCAPE moving into northwest KY and southwest IN. Initially, the increasing moisture should just support scattered light showers; however, 0Z HRRR continues to support the idea that combined lifting effects from the mid-level vort lobes and approaching outflow from overnight convection to our NW should support convective initiation across southern IN between 10-12Z Saturday. With cooler and drier air remaining near the sfc, this convection should remain elevated through much of the morning, pushing east later during the day on Saturday.

Otherwise, light southeast winds and increasing clouds are expected tonight, with lows ranging from the mid 50s east of I-75 to the mid 60s west of I-65. Most areas, especially south of the Ohio River, should remain dry through sunrise Saturday.

SHORT TERM /THROUGH SUNDAY/

Issued at 318 PM EDT Fri May 15 2026

Dry weather across the region this afternoon is expected to continue into tonight as mid-level ridging slides to the east. However, clouds will be on the increase through the overnight ahead of an upper shortwave moving across the region. A broad area of moisture transport will advect into the area overnight along an advancing warm front, with mid-level vorticity pivoting across and adding support for scattered to numerous showers by tomorrow morning. Model soundings continue indicate a healthy low level inversion, which will keep any storms elevated through the morning. However, there should be a large amount of CAPE, though the profile is rather saturated. Morning showers and storms will mostly be unorganized as shear will be marginal, though definitely could see some lightning strikes. PWAT values will also be quite high around 1.5", which is around the 90th percentile of sounding climatology.

The warm front will lift north of the area by the middle of the day, along with the mid-level vorticity, taking away the better forcing. We could end up with a lull of activity during the middle of the day, with outflow boundaries from the morning convection shifting south. This outflow boundary will be the focus area for additional convection development across south-central KY in a better destabilized environment. Model soundings across the south support steeper low level lapse rates and a slightly drier mid-level layer. Combined with strong instability up to 2000 J/kg, higher DCAPEs may result if we see drier mid-levels. As so, SPC has expanded the marginal risk in the D2 slightly more south for wind and hail risk for any convection that fires along remnant outflow boundaries. Most convection activity will decrease by tomorrow evening, but hold on to a chance for the I-64 corridor and north.

For Sunday, dry weather is expected again as ridging moves into the area. Sfc high pressure will be centered over the southeastern US, which will ramp up the WAA flow for the region. This will result in temperatures Sunday afternoon peaking in the upper 80s to low 90s. These high temps will be 10-15 degrees above normal, and could challenge some daily maxT records.

LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/

Issued at 318 PM EDT Fri May 15 2026

Sunday Night through Wednesday Night...

This period is expected to start dry across the region with overnight lows Sunday night in the upper 60s, though the urban areas will remain around 70 for lows.

Moving into Monday, the region will be in a southwest flow aloft and at the surface. A consistent signal of warm air advection will keep temperatures above normal here with afternoon readings warming into the upper 80s to the lower 90s. The warmest conditions will be down south of the Cumberland Parkway region. Looking at soundings across the region, shear profiles look to remain quite weak here and we'll likely see some afternoon mixing which will lower dewpoints into the mid-upper 50s in the east with lower 60 dewpoints out west of I-65. This could produce enough instability produce a few isolated- scattered storms across our far western areas that may linger into the evening hours. Overnight lows Monday night and Tuesday morning will be in the upper 60s to the lower 70s.

For Tuesday, the broad southwest flow will continue across the region with moisture pooling out ahead of an approaching upper trough and a surface boundary. Looking at soundings, with the ridge shifting off to the east, soundings do show a bit of higher level moisture moving into the region aloft, which suggests that we'll have a bit more cloud cover across the region. Insolation will not be as strong as Monday, but the overall synoptic pattern will support afternoon temperatures in the mid-upper 80s with a few 90s down across southern Kentucky. Shear profiles remain rather weak across the region. However, with temperatures in the mid-upper 80s and dewpoints in the 60s will yield enough instability for scattered showers/storms in the afternoon. Scattered showers/storms are likely to continue into Tuesday night as the front drifts closer to the region from the west with lows in the upper 60s.

Frontal boundary looks to bisect the region Wednesday morning and will push off to east during the day and into the evening. Plentiful cloud cover and scattered showers and perhaps a few storms will be possible as this boundary moves through. Temperatures swill cool off a bit as the front heads through, with highs in the upper 70s to the lower 80s. A drying trend will take place Wednesday night as temperatures cool back into the upper 50s/lower 60s.

Thursday and Friday...

Looking into the later week period, frontal boundary looks to slowly sag southward into the TN Valley on Thursday with the upper level flow taking more of a zonal flow aloft while an area of high pressure works across the Great Lakes states. Blended PoPs here look a bit too high and probably will trend downward in future forecasts. In the post frontal airmass, temperatures will be back to seasonal normals with highs in the mid-upper 70s with overnight lows in the mid 50s.

Zonal flow looks to hold into Friday with slightly drier air continuing to work into the region from the west/northwest. A slight moderation in temperatures is expected with highs warming into the upper 70s to the lower 80s.

AVIATION /00Z TAFS THROUGH 06Z SUNDAY/

Issued at 732 PM EDT Fri May 15 2026

This evening and tonight, VFR conditions are expected along with light S/SE winds. Between 06-12Z, a 35-40 kt LLJ will try to work in over HNB and SDF, which could lead to marginal LLWS conditions. During the day on Saturday, primary weather impacts should come from scattered showers and thunderstorms. Coverage and timing of showers and storms remains low confidence and variable between model guidance, but there is medium-to-high confidence that several sites (especially HNB, SDF, and LEX) will see at least a few showers or storms during the day. Lesser coverage is expected for BWG and RGA, but there should still be enough of a threat for a PROB30 mention. Any storms will bring gusty winds, IFR/MVFR VIS, and lower CIGs.

With this being said, prevailing conditions for most of the day on Saturday should be VFR with S/SW winds on the order of 8-15 kt.

LMK WATCHES/WARNINGS/ADVISORIES

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