textproduct: Louisville

KEY MESSAGES

* Scattered showers and thunderstorms will move across the region from west to east this evening (4PM-12AM EST). There is a low chance (5%) that the strongest cells could produce locally gusty winds or small hail.

* Conditions will turn sharply cooler on Thursday, with high temperatures likely (>90% chance) staying under 50 by Friday. There is a low chance for the first flurries of the season Thursday night into Friday, especially for our eastern counties, but the warm ground should prevent anything from sticking.

* High pressure builds in by the weekend, setting up a dry stretch of weather that will last into early next week.

DISCUSSION

Issued at 326 AM EST Wed Nov 11 2026

Overview through Early Wednesday Afternoon...

Looking across the region early this morning, the surface high pressure that has been in place is pushing off to the east. Clear skies and relatively calm winds still remain, with most places currently in the upper 30s to mid 40s. The start of the day on Wednesday will be fairly calm ahead of our previously mentioned low pressure system swinging through the Ohio Valley later today.

Showers and Storms w/Possible Severe Potential late Wednesday...

Examining things at the synoptic scale, shortwave energy currently over the northern Plains is tracking southeastward at the nose of the polar jet. Additionally, weaker shortwave energy over Texas associated with the subtropical jet is moving east-northeastward towards the Tennessee Valley. The two features will interact and phase with each other as the day progresses, promoting cyclogenesis that will produce a deeper surface low over IL/IN/OH by Wednesday evening. While the low center will not move directly over our forecast area, the strong cold front associated with it will pass through during the late afternoon and evening hours.

Ahead of the low, decent southwesterly flow will bring in a brief push of warm air advection and low-level moisture. Highs today will be in the mid to upper 60s, with dew points in the 50s for the western half of the CWA. While not broadly encompassing, a narrow moisture axis develops ahead of the cold front, with about 0.8-0.9" of PW (80-85th percentile climatologically). From recent REFS guidance, this corridor will also have MLCAPE values of 400-600 J/kg by peak heating, as well as fairly steep low and mid-level lapse rates near 7.0 C. Wind shear will be mostly unidirectional aloft (westerly) but quite strong (30-40 kt of 0-6 km bulk shear).

With the impressive kinematics in place we do expect showers and scattered thunderstorms to develop late Wednesday afternoon, moving eastward across the region. The SPC does have a Marginal Risk for severe weather for places west of I-75 with this system, with the primary concerns being damaging winds and isolated small hail. The limiting factors in play with this includes the limited moisture return ahead of the low, as well as the timing of the system. Once we lose daytime heating and transition into the overnight, convective inhibition quickly increases and the thermodynamics involved with this system become less favorable for strong to severe storms.

While there is decent likelihood (50-70% chance) in rainfall for the area, the faster-moving nature of this system will keep accumulations rather low. REFS rainfall amounts from this system are in the 0.2-0.35" range, with LPMM outputting narrow swaths of 0.70- 0.85" of rain with the strongest showers/storms. The current timing of this event for the area is from 4 PM - 12 AM EST.

Return of Cold Weather Late Week and Beyond...

Once the front swings through the area late Wednesday, cold air (-4 to -6 C 850 mb temps from latest LREF) surges in behind it. Rapid pressure rises from the deepening surface low will result in blustery northwesterly winds into Thursday. Sustained winds will be in the 10- 15 mph range, with wind gusts as high as 30 mph. While winds will start to diminish some late Thursday, cold air will continue to be reinforced due to embedded shortwaves from an upper-level low over the northern Great Lakes region/southern Ontario swinging over us. Temperatures on Thursday will be in the upper 40s/low 50s, with highs struggling to get above 50 Friday-Sunday. Overnight temperatures will drop to the coldest we've felt so far this season. Lows on Friday morning will be in the low to mid 30s, with widespread lows in the 20s Saturday-Tuesday.

If enough wrap around moisture remains behind the low late Thursday through Friday, a few rain showers are possible in the eastern half of the CWA. With cold overnight temperatures, a few snowflakes cannot be ruled out. A few LREF members do pick up on this, so that will be something to monitor as this system develops. Surface high pressure builds in by the weekend, setting up a dry stretch of weather that lasts into early next week.

AVIATION /12Z TAFS THROUGH 18Z THURSDAY/

Issued at 641 AM EST Wed Nov 11 2026

VFR conditions will prevail through most of Wednesday before a cold front pushes through the region. The one exception is HNB that has experienced periods of fog and could continue to have patchy fog until 14z. Current light southeasterly winds will shift to the southwest and increase to around 10-12 kt sustained winds and 16-19 kt gusts by midday Wednesday. Cloud cover will increase as the day progresses, with ceilings remaining VFR. Chances for showers and thunderstorms will increase after 20Z continuing through about 06z. There could be brief reductions in visibilities and ceilings with any stronger showers and storms. Once the front moves through, winds will shift to the WNW, with 10-12 kt sustained winds and occasional gusts up to 17 kt. Ceilings will also begin to lower, with MVFR ceilings likely by 06-09z Thursday.

LMK WATCHES/WARNINGS/ADVISORIES

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