textproduct: Louisville

KEY MESSAGES

* Winter storm to bring significant snow accumulations to southern Indiana and north-central Kentucky tonight, with 3-5 inches expected. Snow accumulations of 1-3 inches expected for central Kentucky. Travel impacts are likely for the region tonight and for the Friday morning commute.

* Another quick-hitting clipper system is expected to bring an additional 1-3 inches of snow for areas north of I-64 during Saturday afternoon into Saturday night.

* Very cold airmass will move into the region on Sunday through Monday, as lows will be in the single digits and highs on Sunday in the teens and low 20s. Minimum wind chills may bottom out in the 10 below to 10 above zero range.

* Temperatures will steadily warm Monday afternoon through mid next week.

SHORT TERM /THROUGH FRIDAY/

Issued at 400 PM EST Thu Dec 11 2025

=== Winter Storm Warning for Portion of Forecast Area ===

The Winter Weather Advisory has been upgraded to a Winter Storm Warning for the northern portion of the forecast area, including most of our southern Indiana counties, and north-central Kentucky. The Winter Weather Advisory has also been expanded southward by a row of counties.

A quick-hitting clipper system is currently to our northwest this afternoon, but is expected to arrive by this evening, bringing significant snowfall to areas highlighted by the winter headlines. Deep moisture will overspread our region around or after sunset, leading to an initial onset of mixed p-types as sfc temps could be hovering around the freezing mark. However, will expect a quick change over to all snow shortly after onset as wet bulbing helps us drop below freezing.

We'll see the sfc low move across Missouri this evening, extending a warm front to the east and across the TN Valley. This wave will bring a good amount of forcing overhead, with model guidance showing healthy mid-level frontogenesis band moving across the area in a well- saturated profile. Wind profiles indicate speeds increasing and weak directional veering with height, and combined with the vicinity of the warm front just to our southwest, will support CSI and stronger EPV. With this in mind, combined with deep saturation through the DGZ, we will likely see some heavy snow bands set up across the area, potentially seeing snow rates of 0.5-0.75 in/hour, with perhaps a few bands overachieving and closer to dumping 1 in/hr, especially for our counties in the warning.

After the clipper departs our area tomorrow morning, expect a drier trend for the rest of Friday and into Friday night.

===== Snow Amounts Tonight =====

Forecast snowfall amounts were increased slightly with the afternoon package, with a widespread 3-5 inches expected within the warning area. This area will also have the longest residence time for snowfall, which further adds to the confidence of significant snow amounts in our northeast. In the advisory zone, generally 1-3 inches are forecast, though the southern edge of the headline features the lowest confidence.

Still expect to see a very sharp gradient on the southern end with the warm front cutting into our southwestern CWA. This poses a bust scenario for some of those counties on the edge of the advisory, such as Hardin (KY) or Perry (IN), which could see a dusting to 2" spread south to north across the county. We have to draw the line somewhere, and regardless of where that is, there will be some folks that are under the advisory but will likely end up with little to no snow. In other words, some southern locations could get left out of snow, while the northern part of the county sees an inch or two.

Snow ratios will likely range between 12:1 to 15:1, with the colder temps to our northeast resulting in the higher ratios.

===== Probabilistic Snow Amounts =====

Location Chance of >1" Chance of >2" Chance of >4"

Louisville 94% 77% 35%

Lexington 96% 87% 50%

Frankfort 96% 85% 51%

Madison, IN 98% 95% 64%

Salem, IN 97% 93% 67%

Jasper, IN 92% 72% 55%

Of our population centers, Salem and Madison, IN have the best chance in our CWA of exceeding 6 inches, with roughly a 30% chance.

===== Potential Impacts =====

Majority of the snow is expected to fall overnight, which will help some with limiting overall impacts. However, we will see lingering snow through the morning for the Bluegrass region as the clipper pulls away. We'll still likely see at least some minor impacts, per the WPC WSSI, with some travel impacts and inconveniences expected for the Friday morning commute as road crews work diligently to clear their routes.

LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/

Issued at 400 PM EST Thu Dec 11 2025

===== Friday Night - Weekend =====

Dry weather is expected for the beginning of the long term period, though it will be short-lived as we await another quick-hitting clipper system to drop more snow across our northern CWA. We start out dry for Saturday as well, with considerable temp spreads north to south across the area. Our southern IN and north-central KY counties are forecast to remain below freezing, perhaps some in the upper 20s, while our Lake Cumberland area could see mid to upper- 40s.

As we head into the afternoon and evening time frame, another quick- hitting clipper system looks to put down another swath of snow across our northern forecast area. Model guidance continues to indicate a similar track to the first clipper system, with PoPs ramping up for Saturday afternoon and peaking during the evening hours. The clipper is expected to quickly exit our area by early Sunday morning.

Best chances for advisory level snowfall will be north of I-64, with potential for 1-3 inches. It is also worth mentioning that we won't see much melting between clipper systems, as mentioned in the previous discussion, so we could end up with some considerable snow depths when combining the snowpack of two systems by Sunday morning.

Arctic high pressure will build across the Midwest and Ohio Valley on Sunday, bringing the coldest air of the season so far and amplified by the fresh snowpack. Sunday morning lows are currently forecast to crash hard into the single digits for areas north of the KY Pkwys, with southern IN counties the best chance for 0F temps. These temps, combined with NW sfc winds around 10 mph will allow wind chills to drop to subzero for a large portion, with perhaps 10 below zero wind chills across southern IN. These values would support a Cold Weather Advisory for at least some, if not all of our CWA Sunday morning.

After highs mostly in the teens on Sunday, Sunday night into Monday low may even be colder with high pressure settling near or over top of us. Looking for most lows in the 0 to 10 above range, with perhaps some negative values across our north. The good news is that winds will be lighter with the surface high near or over us. Still, may need to keep a Cold Weather Advisory going through Monday morning as well.

===== Monday Night - Wednesday =====

Dry conditions continue through early week with the arctic high pressure losing hold by mid week. Temps will begin to slowly moderate during this time, but conditions will stay dry at least through Tuesday night. By Wednesday, some cold rain showers could return by overall confidence is low by this time period. Looking for highs in the 35 to 45 degree range on Tuesday, and more solidly in the 40s by Wednesday.

AVIATION /18Z TAFS THROUGH 00Z SATURDAY/

Issued at 1211 PM EST Thu Dec 11 2025

Low stratus deck over the region is moving across the area, though some improvement to cigs is expected for this afternoon. However, VFR will only last a few hours, with lowering cigs and deteriorating conditions for this evening as a clipper system brings accumulating snow for most of the terminals overnight. BWG is expected to be the least impacted, with wintry precip chances unlikely, and cigs expected to remain VFR through the period. However, impacts to flight ops are expected for SDF, LEX, HNB, and RGA tonight. We'll see -SN spread east after 23-00z this evening, with bands of briefly heavy snow capable of dropping vis down to 1-2SM overnight. Cigs could also drop to IFR or MVFR for an extended period of time. Snow will gradually taper off from west to east through the morning, with lingering IFR/MVFR through the rest of the forecast period.

LMK WATCHES/WARNINGS/ADVISORIES

KY...Winter Storm Warning from 7 PM this evening to 10 AM EST Friday for KYZ031>037-040>043-048-049. Winter Weather Advisory from 7 PM this evening to 10 AM EST Friday for KYZ025-028>030-038-039-045>047-053>057-066-067. IN...Winter Storm Warning from 7 PM this evening to 10 AM EST Friday for INZ076>079-091-092. Winter Weather Advisory from 7 PM EST /6 PM CST/ this evening to 10 AM EST /9 AM CST/ Friday for INZ083-084-089-090.