textproduct: Louisville

KEY MESSAGES

* Potential wintry system tonight into Monday that could bring a messy mix of precipitation types to portions of southern Indiana, north-central, and east-central Kentucky. Impacts to the Monday morning commute are possible.

* Additional systems bring rain and warmer temperatures on Tuesday and Wednesday, with steady rain favored in our northernmost counties.

* Highs remain well above normal through the end of the week along with daily rain chances.

SHORT TERM /THROUGH MONDAY/

Issued at 340 PM EST Sun Mar 1 2026

===== Rest of Today =====

Cold air advection pattern has moved into the region today as sfc high pressure builds across the Great Lakes. From the KY Mesonet, there is a temperature gradient north to south across the forecast area, with mid 40s to the north, and low 60s to the south. This is in part to the sfc boundary shifting south of the area today. For the rest of this afternoon and evening, expect to see continued dry weather, with increasing clouds, and winds from the northeast.

===== Messy Wintry Mix Possible Overnight =====

As we head into late tonight and early tomorrow morning, we will be located between the strengthening sfc high over the Great Lakes, the aforementioned sfc boundary to the south, and an approaching mid- level disturbance from the west. Our sfc winds will remain out of the northeast due to our proximity to the sfc high, continuing to provide a low level dry and cold advection flow, but the approaching shortwave will introduce an 850mb jet over western TN and KY, bringing some warm air advection over the cold sfc air in the form of isentropic lift. We'll end up seeing precipitation move in from the west after midnight, expanding in coverage across our area through the early morning hours, and lingering through much of the daytime hours tomorrow. This combination of low level WAA overrunning sfc CAA will support a warm nose aloft, leading to a messy mix of wintry precipitation types, especially along and north of the I-64 corridor. South of the WK/BG Parkways, sfc temps are expected to be slightly warmer, leading to good confidence in that area receiving just plain cold rain tomorrow morning.

There remains some considerable uncertainty in the short term with regards to several factors, including p-types, accumulations, and possible impacts. The best chances for wintry mix shifted just a tick north today, and roughly will be north of a line from Tell City to Bardstown over to Richmond. South of that line, temperatures will likely be warm enough for just plain cold rain. While there appears to be slightly better agreement on the strength of the warm nose, there remains some model divergence on the amount of low level cold, dry air that filters in from the northeast tonight. This is significant because it will play into wintry precip amounts by wetbulbing. If we end up with drier and colder air, stronger wetbulbing would take place and in turn result in higher snow and ice amounts. However, if sfc dewpoints do not get as low as the HRRR suggests, then precip amounts will be in line with the current forecast.

We'll certainly have some dry air in the low levels to work through initially, but once we do so, precip will likely fall as a wet, slushy snow across southern IN, with more of a mix of sleet and freezing rain along the I-64 corridor. Slushy snow accumulations of a coating are possible along/north of the I-64 corridor with some light icing possible. The chance for at least 0.01" of ice is generally 40-50% along I-64, and up to 70% near Madison, IN. The chance for at least 0.1" of ice falls off, with probabilities less than 20%. As for snow probs, the chance for a coating is similar, with 40-50% chance along and north of I-64.

===== Possible Impacts =====

Impacts to the morning commute will be possible across southern IN, but remains uncertain how far south we could see them. As mentioned earlier, any snow will be slushy and wet due to snow ratios around 5:1, but with some freezing rain potential too, could see some slick spots, particularly on bridges and overpasses. One factor working in our favor will be road temps, which are expected to be in the upper 30s and low 40s by tomorrow morning, which will help limit impacts in some regard. However, as mentioned in earlier discussions, any heavier precip rates could easily overcome those warmer sfc temps and cause issues. The biggest issue will be the timing, with the expected peak of wintry precip still between 4-10AM and surrounding the morning commuting hours. Additionally, any impacts seen in the morning will be rather brief as sfc temps warm above freezing by late morning. Given the amount of uncertainty around the forecast and potential brief impacts, decided to continue with the Special Weather Statement for this afternoon package and will continue to monitor closely. An impact-based Winter Weather Advisory is certainly not off the table, but confidence in impacts is just not high enough to issue at this time.

LONG TERM /MONDAY NIGHT THROUGH SUNDAY/

Issued at 340 PM EST Sun Mar 1 2026

===== Tuesday - Wednesday =====

The upper flow pattern will become more zonal by Tuesday, with a sfc boundary shifting north and potentially stalling again along the Ohio River. With strengthening low-level jetting out ahead of a sfc low over the central Plains, we'll see a good amount of isentropic ascent across our area, leading to additional chances for showers, especially north of the WK/BG Parkways. Breezy SSW winds through the day will add to the WAA regime, and could see temps climb well into the 60s, and perhaps some low 70s across our south. That sfc boundary will wobble across the lower Ohio Valley into Wednesday as well, so rain chances will continue for then too. Similar to Tuesday, the better rain chances will be primarily across our northern half of the forecast area. WAA will likely be stronger on Wednesday though, which will lead to a very mild start to the day with morning lows in the 50s, and sfc temps warming well into the 70s by the afternoon. This will also result in dewpoints rising into the upper 50s and near 60, so there's a chance we could realize some afternoon instability and see some thunderstorms develop in close proximity to the sfc boundary.

===== Thursday - Friday =====

The gradual warm up continues for the end of the week as the upper flow amplifies and takes on a western trough and eastern ridge split across the US. This pattern will provide a deep SW orientation of flow through the midwest, where additional shortwaves will ride through and provide additional warming and precip chances. Adding to this synoptic pattern will be the presence of the Bermuda high, which will provide broad return flow into the eastern US, adding a deeper moisture fetch off the Gulf and into the Midwest by late week. Thursday will start off with very mild morning temps in the upper 50s and low 60s, which could challenge some daily warm min temps, especially for SDF and LEX. Temps will warm into the 70s by the afternoon, with additional chances for showers and storms. Friday will be even warmer, with temps close to 80, though likely not warm enough to challenge any daily max temp records. On and off shower and storm chances will continue for the end of the week and into the weekend, though there remains some uncertainty on probabilities for severe chances.

AVIATION /18Z TAFS THROUGH 00Z TUESDAY/

Issued at 1223 PM EST Sun Mar 1 2026

VFR conditions are noted across the area this afternoon, with mainly some high level clouds moving across the region. VFR will continue through the rest of this afternoon and evening, though will see cigs increase in coverage and gradually lower by tonight. By the overnight period, precipitation will move into the region from the west, resulting in a messy mix of wintry p-types for all terminals except BWG. Rain, snow, sleet, and freezing rain are possible by tomorrow morning, but will gradually transition to plain rain by the mid to late morning. Additionally, cigs and vis will lower to MVFR after 11-12z, though could see IFR by the afternoon hours just beyond the forecast period.

LMK WATCHES/WARNINGS/ADVISORIES

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