textproduct: Louisville

KEY MESSAGES

* Upper 30s and low 40s temperatures are expected tonight. Patchy frost may be possible over the far eastern areas.

* Dry and milder to end the work week. Then, rounds of showers and storms on Friday night, and again on Sunday afternoon.

* Cooler and a return to drier conditions to start next week.

SHORT TERM /THROUGH SATURDAY/

Issued at 347 PM EDT Thu May 7 2026

High pressure will keep clear skies and light winds overnight, causing efficient radiational conditions. Looking to see low temperatures in the mid-upper 30s over our far eastern areas. These conditions may allow for some patchy frost development, especially in valley communities. Due to this marginal set-up and patchy extent, have opted to issue an SPS for these areas. This SPS runs through 12Z.

High pressure will steadily shift eastward on Friday. Southwesterly flow will allow temperatures to increase to slightly below normal in the upper 60s and low-mid 70s.

In the evening, a shortwave trough will amplify as it swing through the mid-Mississippi Valley and into the lower Ohio Valley. Ahead of this feature, a 40kt LLJ will help to increase lift over the region. Scattered to numerous showers and a few isolated storms will move through the northern half of the region. These showers and clouds will dissipate by mid morning as the shortwave pushes off to the northeast. Only expecting about a quarter of an inch of rainfall from this system over southern Indiana and northern Kentucky. The cold front associated with this system will stall in over the Ohio River. Therefore, temperatures will continue to warm into the mid 70s for Saturday.

LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/

Issued at 347 PM EDT Thu May 7 2026

Sunday - Sunday Night...

Broad troughing will overspread the eastern CONUS, with two distinct shortwaves moving towards that part of the country. The first shortwave, ejecting from the Rockies to the central Plains and mid- Mississippi Valley Saturday through Saturday night, will move over the Ohio Valley Sunday into Sunday night. The second shortwave, that is currently an upper-level low over the Baja, will move over the SE CONUS on Sunday. The northern periphery of the shortwave could clip our southern CWA, however most of that system will remain to our south. With us getting into the range of CAMs, as well as observing the trends of global model guidance, the phasing of the two shortwaves continues to be delayed and pushed further to the east, considerably limiting how strong the system would be over us.

Additionally, while there is some uncertainty of the exact timing, a cold front extending from Canada looks to move through the region sometime during the morning hours on Sunday. Limited instability and a disjointed shear profile ahead of the front will also limit the potential for stronger thunderstorms. LREF probabilities of SBCAPE > 500 J/kg have also trended down over the previous runs, with most places only having a 5-25% chance. While showers and some thunderstorms could take place (35-50% chance), the concern for strong to severe storms to develop right now is very low. As has been mentioned in previous discussions though, if things trend in the opposite direction and a more robust system develops prior to moving over us, the concern for a larger threat could increase.

Monday - Tuesday...

With the shortwaves departing off to the east, surface ridging will fill in, allowing for a cool and dry start to the workweek. Temperatures will remain below average on Monday and Tuesday, with afternoon highs ranging between 5-10 degrees below normal. Monday and Tuesday morning lows will be closer to 10-15 degrees below normal, with temperatures in the 40s currently forecast.

Tuesday Night - Thursday...

A shortwave and associated surface low will move towards the Great Lakes Region Tuesday evening. While guidance has not yet honed in on the placement/timing of this feature, it would provide another round of showers and some storms if it moves over us. Temperatures will also be colder than average, with morning lows in the 50s and highs in the mid 70s. With guidance uncertain on the progression of this feature, the outlook for Thursday is murky. Some surface ridging will fill in after the surface low departs, but another shortwave will trail quickly behind and bring another potential round of showers and storms. Some guidance has the system entering the region late Thursday, with other guidance waiting until Friday to have the system move in. As a result, chances for precipitation on Thursday are low (<20%).

AVIATION /00Z TAFS THROUGH 06Z SATURDAY/

Issued at 758 PM EDT Thu May 7 2026

Sfc high pressure currently centered over the Lower Mississippi Valley will keep flight categories VFR with mainly clear skies and light winds out of the south or nearly calm. This will last through the forecast period. The only potential impacts will be increased winds in the afternoon with some afternoon mixing and near the end of the period we could see increased clouds tomorrow night ahead of a system that will increase rain chances.

LMK WATCHES/WARNINGS/ADVISORIES

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