textproduct: Louisville

KEY MESSAGES

* Strong to severe storms are possible early Wednesday morning through Wednesday evening. Multiple waves of storms are possible, with all severe hazards possible. The magnitude of the severe storm threat remains uncertain, with several mitigating factors existing.

* Cooler and quieter weather expected Thursday through Saturday.

* Another chance for rain, and possibly storms, returns by late this weekend.

SHORT TERM /THROUGH WEDNESDAY NIGHT/

Issued at 345 PM EDT Tue Mar 10 2026

A mix of sun and clouds are over the area this afternoon, though a WAA regime has allowed temps to reach the low 70s so far. Still expect to see temps reach the mid 70s as we reach our peak diurnal time. A few isolated light showers remain possible this afternoon and evening due to the WAA pattern, but have kept chances low given the lack of forcing over the area for now. Precip chances increase after 06z tonight as better forcing arrives when a strengthening LLJ moves over the lower Ohio Valley.

There is rather good confidence in seeing strong to severe storms tomorrow, but confidence remains limited on timing. More details are provided below on those uncertainties and potential scenarios we could see play out.

Besides the shower and storm chances through the day, we'll also have gusty south-southwest winds in the warm sector out ahead of the front. HREF wind gust probs exceed 40-50% for gusts over 40mph through tomorrow, due to mixing down the LLJ and a tight sfc pressure gradient. This will also aid in boosting the WAA, with temps forecast into the 70s again, and dewpoints in the mid-60s as our moisture transport vector is maximized across the region.

As the cold front passes through the area late tomorrow, we'll see precip chances taper off from west to east, with only some lingering showers possible in our far east by the late evening hours. Currently think that the front could be passing the I-65 corridor by 22z Wed, and completely through our area by 00z Thu. This would ultimately put an end to our severe chances around or just before 00z. There is rather good confidence on end timing and FROPA passage, but as mentioned before, there is less confidence leading up to that.

===== Forecast Uncertainty and Changes =====

There remains considerable uncertainty around the timing and evolution of storm chances tomorrow, with some CAMs showing early morning rounds of showers and storms, and other CAMs keeping us mostly dry in the morning and resulting in more severe activity in the afternoon.

SPC maintains the Marginal Risk across southern IN in the Day 1 Convective Outlook, which is for Wednesday early AM for our area. The tornado outlook has been updated, and still includes the 2% risk, but now also includes a CIG1 intensity for southern IN. This indicates the potential for tornadoes up to EF2 strength before 12z Wednesday morning.

WPC updated their Excessive Rainfall Outlook, and expanded the Marginal Risk to now include southern IN. This is in line with thinking there will be multiple rounds of showers and storms moving across that area, which could result in some minor flooding issues. With strong moisture transport, PW values are expected to be near 1.5", which would be around the daily max for sounding climatology. So heavy rainfall will be expected, but combined with multiple rounds moving over the same area, we could see some flooding issues arise.

Greater uncertainty comes after 12z Wednesday, where we maintain the Slight risk and 2% tornado outlook, but have some doubts about severe potential through the afternoon as the cold front approaches. Considerably higher tornado risk is located across Ohio and northern Kentucky, where better forcing is expected to be through Wednesday.

*** Possible Scenario 1 ***

There is growing confidence on seeing morning thunderstorms, potentially strong to severe, move in a southwest to northeast trajectory mainly along and north of the Ohio River tomorrow morning. Some discrete cells or a cluster of storms would be possible, with some uncertainty on how much low-level stability could be present. If we are able to erode the cap, as the HRRR or other MPAS models suggest, 0-1km SRH values exceeding 200 m2/s2 will pose a tornado risk mainly across southern IN. This lines up quite well with the SPC tornado risk and CIG1 intensity mention.

In the event that we see possibly two or more rounds of strong to severe storms in the morning, it could certainly limit the severe probability for the afternoon and ahead of the approaching cold front. Morning showers and storms will likely inhibit recovery of instability across the area, resulting in a line of showers and embedded thunder to pass through the area during the afternoon time frame with a lower severe potential. This scenario would also provide a greater flooding risk with repeating rounds of heavy rain along and mostly north of the Ohio River.

*** Possible Scenario 2 ***

There is more uncertainty around this scenario, which features less precip coverage and/or more low-level capping during the morning hours. If we see less activity in the morning, as the NAM suggests, then that leaves the door open for better realization of instability through the afternoon, and higher chances for severe storms along or ahead of the cold front pushing through during the afternoon. All severe hazards would be on the table for the afternoon in this scenario, though damaging winds and a few tornadoes would be the primary threats. Heavy rainfall will also be expected given the high PWATs, though flooding may not be as much of a concern with less training and a more progressive line move through.

LONG TERM /THURSDAY THROUGH TUESDAY/

Issued at 345 PM EDT Tue Mar 10 2026

Thursday through Saturday...

As the cold front exits the region to the east, sfc high pressure and cooler air fills in over the CWA. Morning lows drop into the mid 30s, with afternoon highs barely getting above 50. For Friday, an upper shortwave and associated jet streak will move over the upper Midwest, bringing a compact sfc low with it. Its cold front will skirt over the northern edge of the CWA, though no precipitation is expected as it passes through. Ahead of the frontal passage Friday afternoon, SW wind gusts around 30-35 mph are possible, with temperatures rebounding into the low 60s. Saturday will be calm and warm, with elevated SW flow at the low-levels helping temperatures rise into the id-to-upper 60s.

Sunday through Tuesday...

The northern upper jet digs southward towards the Plains on Sunday, becoming a well-amplified upper trough. A robust sfc low develops ahead of the jet streak on the right side of the trough axis, moving over the Midwest and Ohio Valley Sunday afternoon through Monday morning. Strong SW flow will allow temperatures on Sunday to rise into the low 70s, as well as produce gusty winds around 25-30 mph. Showers and a few thunderstorms are possible ahead of the frontal passage, though the intensity of the storms is still uncertain. Model guidance is in decent agreement over the broad synoptic setup for the event, with the finer details such as the timing and mesoscale features not being as clear.

A strong surge of cold air will fill in after the frontal passage, with temperatures dropping into the upper 20s/low 30s Monday morning. Rain will transition to snow late SUnday night/early Monday, and strong NW flow will allow for some snow showers to develop during the day on Monday. As sfc high pressure continues to fill in over the region, gusty conditions will lessen by Monday evening, becoming calm for the day on Tuesday. Tuesday morning lows will be in the upper teens/low 20s, with afternoon highs only getting into the low-to-mid 40s.

AVIATION /00Z TAFS THROUGH 06Z THURSDAY/

Issued at 721 PM EDT Tue Mar 10 2026

Currently seeing VFR conditions and breezy S/SW winds around 9- 13kts. These conditions will continue through 6Z. MVFR CIGs will move in from the west ahead of some showers and storms. These showers and storms will mainly impact the northern half of the region through the morning hours. We may see a brief break in storm activity in the mid-morning, before another line forms along the cold front in the afternoon. The cold front and storms will push SE through the region in the afternoon and evening. Precip and convective activity will quickly cease following frontal passage. Winds will also shift from the SW to the NW.

LMK WATCHES/WARNINGS/ADVISORIES

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