textproduct: Louisville

KEY MESSAGES

* Milder temperatures and intermittent light rain chances are expected during much of the upcoming week.

* Unseasonably warm temperatures are likely around Christmas, with temperatures expected to be 15-20 degrees above normal.

* Mild weather continues into the first part of the weekend, but will gradually trend cooler by Sunday with a series of reinforcing cold fronts. There is low, but increasing potential for a stronger system Saturday night into Sunday that could bring strong to severe storms.

SHORT TERM /THROUGH TONIGHT/

Issued at 319 AM EST Mon Dec 22 2025

Cool and dry conditions continue this morning as high pressure remains in control over the middle Appalachians. Upper-level cirrus clouds are streaming overhead this morning, with an expansive area of lower stratus noted from the Ozarks across the lower Mississippi Valley and into the Gulf states. While temperatures are seasonably cold in the 20s and 30s this morning, milder air will quickly return to the area later today. The sfc high will move east toward the mid- Atlantic coast this afternoon as low pressure deepens across the northern Plains, with low-level winds veering from easterly this morning to southerly by this afternoon. Warm advection will help temperatures to warm into the 50s this afternoon, with readings closer to 50 the farther north you go and closer to 60 the farther south you go.

In addition to drawing warmer air up from the Gulf, S/SW flow between the sfc and 800 mb will also increase low-level moisture across the Ohio Valley this afternoon and evening, with PW values increasing from around 0.3" to 0.9-1.0" over the next 18 hours. With 850 mb flow increasing to around 40-45 kt this evening, we should begin to see scattered light rain showers develop across the area by mid-to-late afternoon as this low-level SW flow will support moist isentropic ascent. Scattered light rain showers should continue into early Tuesday morning as the H85 jet should remain in place over the region. With moisture lacking in the mid- and upper-levels of the atmosphere and deep-layer forcing remaining well to the north of the region, precipitation amounts should remain light, with most areas only receiving a few hundredths to a tenth of an inch of rain through Tuesday morning.

While near-sfc stability should keep stronger winds aloft, 8-15 mph southerly breezes are expected to continue tonight into Tuesday morning. Thanks to this mild breeze and ample low-level moisture, temperatures will struggle to fall much tonight, with lows expected in the mid 40s to around 50 Tuesday morning.

LONG TERM /TUESDAY THROUGH SUNDAY/

Issued at 319 AM EST Mon Dec 22 2025

Tuesday through Christmas Eve...

By sunrise Tuesday, the low-level jet and isentropic ascent which will support scattered rain showers tonight will begin to weaken and push off to the east. At the same time, a sfc cold front will move into the Ohio Valley from the NW, but it is expected to stall out before making it through the region. While drier mid-level air will work into the region from the north during the day on Tuesday, stubborn moisture in the lowest 5 kft should keep low clouds overhead. While coverage of rain showers is expected to diminish during the day on Tuesday, soundings show there may be sufficient llvl moisture for patchy drizzle through the day. Regardless, any precipitation which does fall should be light and won't be particularly impactful.

Temperatures will be a bit tricky on Tuesday as ample low-level moisture would typically support a suppressed diurnal range, keeping highs down. For what it's worth, NBM guidance gets much of the area into the upper 50s and low 60s Tuesday afternoon, though there is a fairly wide spread between the upper and lower tails of the temperature guidance. Have nudged temps down a bit on Tuesday, but it should still end up a bit milder across the area compared to Monday.

Tuesday night into Wednesday morning, high pressure over the Great Lakes may try to nudge the sfc front toward the KY/TN border, bringing cooler temperatures and decreasing cloud cover toward our southern IN and northern KY counties. If we did clear out, it would be a fairly good setup for fog, but confidence in this is pretty low right now. Regardless, there should be a pretty strong north-south temperature gradient over the region Wednesday morning. There could also be a few lingering light showers across southern KY into Wednesday morning, but these shouldn't be too impactful.

Christmas Eve should be a mostly dry day as upper-level ridging starts to lift the stationary front over the region to the north. How far north the front progresses during the day will impact high temperatures, with the current forecast featuring highs near 60 north of I-64 and in the upper 60s along the KY/TN border. Rain chances will increase once again Christmas morning as a mid-level shortwave passes to the northeast of the area.

Christmas Day through Friday Night...

Above normal temperatures and intermittent rain chances are expected to continue for Christmas Day through Friday as additional shortwave disturbances progressively dig into the upper-level ridge over the south central US. There is still a bit of forecast uncertainty in exactly how mild high temperatures will be, as a more amplified upper ridge will lift a warm front farther to the NE of the area, making temperatures in the upper 60s to around 70 more likely. This time frame also shouldn't be a complete washout, as precip chances will ebb and flow as upper-level disturbances pass by the region. There is greater confidence that low temperatures will be near record warm values, as suppressed diurnal ranges in temperatures should continue through the end of the week.

Next Weekend...

While most of the systems over the next week should feature light precipitation and limited impacts, there is increasing potential in a more impactful system moving through the area Saturday night into Sunday. The synoptic trough which will be fairly static along the west coast this week will begin to eject out across the Rockies and into the Plains Saturday into Sunday. As it does so, it will attempt to phase with a polar stream trough moving across Canada. If this phasing is successful, as is more prevalent in the ECMWF/EPS solutions, this could bring an amplified upper trough and strong sfc cold front through the Ohio Valley Saturday night into Sunday. With extended range progs showing dewpoints in the low 60s ahead of this system, there would be favorable ingredients for strong to severe storms ahead of cold FROPA. If the two upper waves don't phase, as is more typical in the GFS/GEFS, then a more muted, weaker system would move through the region next weekend. Extended range AI/ML severe convection guidance hasn't yet converged on too concerning of a solution, but this is something that bears watching over the next several days.

Otherwise, temperatures should trend downward by the end of next weekend, with the stronger/more amplified solutions favoring at least a brief pattern reversal back to below normal temperatures. Drier weather is also favored early next week, though forecast confidence is still pretty low this far out.

AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 1223 PM EST Mon Dec 22 2025

VFR conditions continue this afternoon, though incoming lowering cigs and rain chances will impact flight categories by this evening. MVFR stratus deck and -SHRA are expect to spread throughout the area this evening. Sfc winds increase as a LLJ strengthens overhead, leading to southerly sfc winds gusting over 20kts after 00z, and LLWS during the overnight. Light rain should taper off by morning for most terminals, but the best chance for lingering precip tomorrow morning will be for BWG. Otherwise, MVFR cigs continue tomorrow, with HNB having the best chance of dropping to IFR before 12z.

LMK WATCHES/WARNINGS/ADVISORIES

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