textproduct: Louisville

KEY MESSAGES

* Waves of showers and thunderstorms are expected this evening into Wednesday, bringing widespread beneficial rainfall to the area. Widespread rain totals of 1-2" are likely, with localized heavier totals possibly leading to a few instances of high water or minor flooding.

* High temperatures look to warm back into the 70s this weekend, ahead of a cold front on Sunday. Showers and some strong storms will be possible on Sunday.

SHORT TERM /THROUGH WEDNESDAY NIGHT/

Issued at 354 PM EDT Tue May 5 2026

The MCV that was mentioned in the previous forecast discussion is currently draped over the northern portions of our CWA, slowly departing to the northeast. With little instability over our area, the system has weakened to one of light-to-moderate rain showers with a very isolated rumble of thunder.

Looking ahead to this evening, the frontal boundary over central Indiana and southern Illinois is slowly beginning to move southward towards our area. As the front moves in, a mid-level shortwave enters from the west, with a 40-50 kt low-level jet forming beneath it across our CWA. The combination of this, along with deep moisture transport and hi-res guidance depicting a developing surface low near our area along the boundary will help support multiple rounds of showers and isolated-to-scattered thunderstorms this afternoon through tonight. Guidance continues so show between 1-2" of rainfall from this event, with some locally higher totals if training storms along the front take place.

HREF guidance continues to keep our area in limited instability (< 250 J/kg MLCAPE) that will quickly decrease after sunset this evening. This should help limit the potential for strong-to-severe storms to develop, which is helpful given the impressive overall wind shear profile over our area tonight. Plenty of speed and directional shear will be present, with HREF guidance showing a peak 0-3 km SRH > 650 m2/s2 shortly after midnight. The elevated nature of this setup does show up in the ESRH, with values less than 60 m2/s2 depicted throughout the event. The SPC continues to have our far western counties under a marginal risk for severe weather, with the primary threat being damaging winds. An area of interest early this evening will be in the SW portions of the CWA once showers and storms begin to develop. Dew point depressions of 15-20 degrees F and dry near-surface conditions could create an inverted V profile at the low-levels, and with the formation of a strong low-level jet this evening, gustier winds could be experienced by some of those showers and storms.

By Wednesday, the front slowly departs to the southeast, becoming nearly stationary over northern Tennessee. With multiple perturbations riding the front, rounds of rain showers will be possible (35-50%) over our southern counties, with accumulations less than 0.75" forecast. For the rest of the area, expect dry and cool conditions, with highs in the low 60s. By Wednesday night, surface high pressure will begin to build in, helping push the near- stationary front away from the region and ushering in a period of calmer weather.

LONG TERM /THURSDAY THROUGH TUESDAY/

Issued at 354 PM EDT Tue May 5 2026

===Dry and Cool Thursday and Friday===

Broad troughing and surface high pressure will keep conditions dry and cool through the end of the week. Looking to see highs in the mid-upper 60s and lows in the upper 30s and low 40s on Friday morning. Some areas in the far northeastern Bluegrass may see mid 30s, where some frost development will be possible.

===More Active Weather This Weekend===

Late Friday night and into Saturday morning, a shortwave trough will amplify as it swings through the Upper Mississippi Valley and into the Ohio Valley. This feature will allow a surface low pressure to develop and move through the Great Lakes, dragging a cold front southeast through the lower Ohio Valley. Southwesterly flow out ahead of the cold front will allow for moisture and temperatures to increase. A line of showers is expected along the front and some embedded thunder will be possible, given weak elevated instability.

Behind this front, showers will quickly dissipate as surface high pressure builds in behind. We won't see much of a dip in temperatures, since southerly flow will return quickly on Saturday afternoon. Looking to see temperatures in the mid-upper 70s for Saturday.

On Sunday, a shortwave ejecting out of the desert southwest will move through the Tennessee Valley. This feature will develop a surface low pressure system. At the same time, broad troughing over the Great Lakes will try to bring another wave through the Ohio Valley. These two features may phase, but for now thinking the southern stream shortwave will precede the northern stream wave. Numerous showers and some storms are expected for Sunday. Looks like we will see 1000-1500J/kg of SBCAPE, but weaker shear (30kts of 0- 6km Bulk Shear). Will continue to monitor Sunday for severe storms potential.

===Drier Early Next Week===

High pressure will follow the cold front on Sunday night, bringing drier and cooler air to the start of next week.

AVIATION /18Z TAFS THROUGH 00Z THURSDAY/

Issued at 228 PM EDT Tue May 5 2026

An area of rain showers has entered the northwest portions of the area, currently over HNB and near SDF and BWG. This area of rain showers is paired with a cold front that will slowly move to the southeast this evening and overnight. Widespread rain showers are expected across the terminals through at least midnight, with LEX and RGA maintaining showers into the morning hours on Wednesday. Scattered thunderstorms are also possible during this event, but confidence is not high enough to include as a prevailing condition.

As the front moves over the terminals tonight, winds will shift from the SW to the NNE, with gusts ending behind the frontal passage. Brief periods of LLWS are possible tonight, especially towards the SE portions of the area, but confidence was too low to include in the TAF. As the front moves through, especially after midnight, ceilings will drop to low MVFR/IFR, persisting until around midday Wednesday when ceilings slowly start to improve.

LMK WATCHES/WARNINGS/ADVISORIES

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