textproduct: Louisville

KEY MESSAGES

* Scattered showers and isolated thunderstorms are expected this morning mainly across south central KY. Isolated flooding chances are decreasing, but will still be possible through late morning. Precipitation chances should decrease from NE to SW this afternoon.

* Drier conditions are expected tonight into Sunday morning before another another chance of showers returns to mainly southern Kentucky again on Sunday and Monday.

* A much drier weather pattern will take shape across the region as we move into the middle of next week. Dry weather with seasonal temperatures and lower humidity are expected for much of the work week.

SHORT TERM /THROUGH SUNDAY NIGHT/

Issued at 214 AM EDT Sat May 30 2026

This Morning...

Over the past 12 hours, rich moisture over the TN Valley has been slowly creeping northward into western and south central KY. Latest KY Mesonet obs highlights the strong gradient between sfc dewpoints in the low 70s along the KY/TN border and dewpoints in the mid-to- upper 50s across northern KY. This moisture return has come about in part thanks to a subtle mid-level vort max moving across the mid-MS valley which is expected to drift southeastward over the next 12-18 hours. Along and south of the dewpoint gradient, mesoanalysis shows a pool of 600-1200 J/kg CAPE, indicating some fuel is available for showers and storms to develop. However, convective activity has remained fairly limited in our southern counties so far, possibly because the forcing is pretty weak and ill-defined.

With that being said, as the subtle mid-level disturbance crosses the TN valley later this morning, hi-res guidance suggests that increasing 925-700 mb southerly flow should result in scattered development of stronger showers and a few storms. As referenced in the previous discussion, deep warm cloud depths and weak cloud layer winds will lead to slow cell movement, and clusters of heavier rain could linger over the same areas for several hours. As a result, still think there is a threat for heavy rainfall amounts and localized flooding between now and late morning. 0Z HREF continues to show isolated swaths of 2-4" on 6 hr QPF LPMM plots, with the greatest chance for these heavier totals expected along and south of the Cumberland Parkway.

Across the northern half of the CWA (especially along and north of I- 64), dry conditions are likely to continue, with the main sensible weather phenomena being increased clouds and slightly muggier air. Morning low temperatures should range from the upper 50s in the northeastern CWA to the upper 60s to around 70 along the KY/TN border.

This Afternoon through Tonight...

The mid-level disturbance responsible for lifting moisture northward this morning should slide to the southeast by this afternoon. Behind this disturbance, increasing heights to the north of the region should help to push the boundary/moisture gradient over the area back to the south, with drier NE flow pushing into the region this afternoon. As a result, PoPs will steadily decrease from NE to SW this afternoon and evening, with isolated showers and storm chances mainly continuing across far southern and southwest KY.

Dry weather should continue over north central KY and southern IN, with scattered high clouds leading to filtered sunshine. Temperatures this afternoon should make it into the upper 70s and low 80s in most locations, with the main difference being the drier air to the northeast and the muggier air to the SW.

Continued E/NE flow this evening into tonight should accelerate the dry air surge farther to the SW, though this should slow by around sunrise Sunday. Dry weather is expected across the area, with less moisture in the air allowing temperatures to fall into the 50s in most locations outside of our southwestern most counties, which will likely be in the low 60s to start Sunday.

Sunday and Sunday Night...

During the day on Sunday, the mid-level ridge axis should spread back to the east and be centered over the area as troughing over the northeast US retreats slightly. This should cause the low-level NE flow bringing drier air into the region to weaken, allowing the moist air mass to the SW of the area to creep back to the north once again. Once again, large-scale forcing will be pretty weak on Sunday, and there should be a sharp gradient between more moisture in southern KY and less moisture in northern KY and southern IN. As a result, isolated to scattered shower and storm chances should mainly be confined to south central KY Sunday into Sunday night.

Temperatures Sunday should be fairly similar to Saturday, with highs in the upper 70s and low 80s across the area. More moisture in the column Sunday night should lead to milder low temperatures across the area ranging from the mid 50s in the northeast CWA to the mid 60s along the KY/TN border.

LONG TERM /MONDAY THROUGH FRIDAY/

Issued at 214 AM EDT Sat May 30 2026

Monday and Monday Night...

At the beginning of the week, medium-range guidance remains relatively unchanged in showing a highly-amplified blocking pattern across North America. An upper high over central Canada and the north central CONUS will be surrounded by two upper lows, one over the northwest US with the other extending from the Canadian Maritimes down into the northeast US. This upper-level height pattern will support north-northwesterly flow across the Ohio Valley through much of the week, separating a cooler and drier air mass to the northeast from a warm and moist/unstable air mass to the southwest.

Monday, the gradient between the two air masses will still be close to central KY and southern IN, with more humid conditions and better rain chances the farther south and west you go (and vice versa). One persistent signal over the past few runs in the ECMWF guidance is some MCS-like features descending from the mid-MS valley Sunday night through Monday evening. The pattern, which features a sharp NE- SW gradient in CAPE and subtle disturbances within the upper ridge, is supportive of some more organized convective complexes. However, AI/ML severe hazards guidance and deterministic progs continue to show the highest likelihood of any MCSs remaining to the southwest of our area, though it will be close to areas along and west of the Natcher Parkway.

Monday evening into early Tuesday morning, a shortwave on the western edge of the upper low over the northeast US should cause mid- and upper-level heights to fall across the region, with sfc high pressure dropping south towards the Ohio Valley behind this wave. This should usher in drier NE flow, pushing the humid and unstable air mass well to the SW of the region.

Tuesday through Friday...

The omega block pattern will begin to break down during the middle of next week, with the upper high over Canada drifting to the southeast as northeast US troughing also begins to eject out into the north Atlantic. As this upper-level pattern shift takes place, sfc high pressure over Hudson Bay will sink into the Great Lakes, resulting in northeasterly low-level flow into the Ohio Valley with north and northwest flow aloft. Drier air is expected to sink into the region within this flow regime, with ensemble mean PWATs dropping to around the 10th percentile of climatology Tuesday into Wednesday. As a result, Tuesday through Thursday of next week looks to be dry across southern IN and all of central KY.

While the source region of the air mass moving into the area next week is quite cold (i.e., a cP air mass), it should undergo quite a bit of modification before it makes it to our area. As a result, temperatures should only be marginally cooler during the middle of next week, with highs in the upper 70s and low 80s and lows in the 50s and low 60s.

By the end of next week, the pattern should become more zonal and progressive across the lower 48, with the sfc high moving into the southeast US. This should allow for moist return flow out of the Gulf to resume by Friday, with sfc dewpoints and PWATs climbing. While ensembles show the potential for a decaying cold front coming down from the north, in general, late next week is expected to bring a return of garden-variety summertime showers and storms, with temperatures favored to gradually increase as well.

AVIATION /12Z TAFS THROUGH 18Z SUNDAY/

Issued at 702 AM EDT Sat May 30 2026

For the northern TAF sites of HNB/SDF/LEX/RGA, VFR conditions are expected through the upcoming TAF period. Will see some mid-high level clouds continue to stream southeast through the region. Winds will start off light this morning out of the northeast and then gradually pickup through the morning. Could see a few 15-20kts over at LEX and maybe SDF this afternoon. Look for winds to diminish toward sunset, but will remain out of the northeast overnight at 3- 8kts.

AT BWG, rich boundary layer moisture will remain in place with widespread rain showers continuing through the morning hours. Cigs will run down in the low end of the MVFR range with a few drops to IFR at times. Vsbys will be restricted by rain showers, with mainly MVFR vsbys, but a few drops into the IFR range are possible through 30/15Z. Expecting conditions to improve by mid-late morning with showers diminishing and cigs coming back up through the MVFR range. Current thinking is that we'll see a return to VFR cigs by early-mid afternoon. Surface winds will remain out of the northeast through the period.

LMK WATCHES/WARNINGS/ADVISORIES

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