textproduct: Louisville

KEY MESSAGES

* Precipitation, mostly in the form of rain, will arrive late Saturday afternoon, early evening with a few location across southern IN seeing a quick burst of snow or rain snow mix. Little to no impacts expected

* Another shot of cold air for Sunday with gusty winds making it feel rather blustery.

* Winter storm system Monday night into Tuesday will bring a wide spread of wintry weather types to the area ranging from impactful accumulating snow, wintry mix with some locations seeing only rain.

SHORT TERM /THROUGH TONIGHT/

Issued at 419 AM EST Sat Nov 29 2025

The main focus for the short term will be the arrival of a strong storm system coming out of the central plains moving through the Ohio Valley and into the Great Lakes by Sunday morning. Short range, hi-resolution guidance is doing a good job this morning with the main main precipitation shield that is currently stretches from IA through most of MO into western AR, with mainly snow falling north of a line from St. Louis to Kansas City.

As this system approaches during the morning, we will initially see high clouds as the main precipitation shield will be to our west through IL into MO and AR. A very strong 60-65kt LLJ behind the precipitation will continue to advect warm and moist air northward into the Ohio Valley. It appears the hi-res short range guidance is showing a much clearer picture on where this storm system is headed and where most of the precipitation will fall today into tonight. Current guidance takes the sfc low as well as the best overall dynamics and lift and keeps it to our west over IL and then northward through the northern half of Indiana. As warm and moist air advection increases ahead of this system during the day, dry air associated with the colder air at the surface will initially keep most if not all of the precipitation from reaching the ground. Model sounding show a good dry layer between 800-900mb and any snow that may try to form this morning or early afternoon will initially sublimate as it works through this dry layer. At best, we may see a few flurries or flakes across southern IN and parts of norther KY through the first half of the day.

Our best chance for precipitation arrives late afternoon into early evening as band of precipitation associated with leading edge of the LLJ will work along the Ohio River northward between 22z to 01z. There may be enough cold air north of the Ohio River that we could see an initial burst of snow or rain/snow mix but the trend in guidance seems to be that the warm layer wins out scouring out the near sfc cold air before the main precipitation arrives. While it is still possible that a few of our far northern southern IN counties could see a quick burst of accumulating snow, the likelihood of that happening have been dropping since yesterday as most of the forcing works north and the WAA wins out. Most will just see rain as the precipitation arrives later this afternoon and early evening.

Scattered light to moderate rain showers are expected through the evening and overnight Saturday into Sunday morning with temperatures holding fairly steady in the 40s to upper 30s. Wind gusts of 20-30 mph are expected as the LLJ pushes through the Ohio Valley this evening and a tight sfc gradient associated with the passing storm system.

Strong cold front works in from the west to the east quickly Sunday morning, with winds shifting from the south to the west behind the front. This will also be followed by strong reinforcing shot of cold air behind it. Temperatures will quickly drop into the mid 30s and then hold steady and slowly drop through the day. Sunday will be cold and blustery under mostly cloudy skies with winds still gusting to around 20-25 mph, making it feel like it is in the mid 20s.

LONG TERM /SUNDAY THROUGH FRIDAY/

Issued at 419 AM EST Sat Nov 29 2025

In the long term our attention turns to the next system that will impact the region late Monday into Tuesday. Shortwave trough working out of the Four Corners and through the southern Plains Monday night will interact with a developing sfc low coming out of the western Gulf. As the shortwave trough axis works across the OH and TN Valleys, the sfc low tracks across the southeast towards the Carolinas/Mid-Atlantic coast by Tuesday afternoon.

This will advect Gulf moisture Northwest into the Ohio Valley during the day Monday. The combination of isentropic lift associated with the warm and moist air advection and a mid level jet streak ahead of the mid-level trough axis, we will not be lacking for lift and forcing allowing for widespread moderate to potentially heavy precipitation to develop over the area Monday night into Tuesday.

As was mentioned in the previous forecast, while this would normally be a classic setup for a winter storm over the Ohio Valley, we will be lacking a strong deep cold airmass to keep the precipitation as mostly snow. While the deterministic guidance of the GFS and EURO ensembles agree that we will likely see a wide variety of p-types over the CWA, the confidence on where it will snow, where it it will be a wintry mix of snow, sleet and even freezing rain to even just plain rain remains the main challenge. We continue to see consensus in the models suggesting we will see a NE to SW snow/mix/rain line bisect the Common Wealth but where does this boundary sets up remains the main challenge in the forecast. The latest 00z run of the deterministic had the ECMWF keeping that line along the WK/BG Parkways while the GFS had shifted the warmer air further north the wintry mix line along the Ohio River. As we go through the weekend we will start to see the the guidance between the deterministic models to come together on a common solution helping us increase overall confidence. For now, to help with messaging of potential impacts, we will stay away from specific numbers and focus more on potential impacts and general placement for the various p-type associated with this system.

Once we get through this system on Tuesday, the rest of the week looks to be dry as our forecast will be dominated by sfc high pressure through the region. Temperatures will remain below normal with highs mainly in the mid/upper 30s with the possibility of some 40s. We could see the next potential system arrive by the start of next weekend.

AVIATION /06Z TAFS THROUGH 12Z SUNDAY/

Issued at 116 AM EST Sat Nov 29 2025

As the next system approaches from the west, high clouds will continue to increase over the area, for the most part, the forecast period will remain VFR but near the end is when we will start to see the impacts from the approaching system. As we go into the day winds will increase more out of the south-southeast as the system approaches. Clouds will start to lower as more moisture advects into the region. The main impacts will be a push of snow or snow/rain mix for around SDF between 20-00z. This push and potential burst of snow will arrive on the leading edge of a robust 60-65kt LLJ. Went ahead and added LLWS to SDF Taf after 00z.

LMK WATCHES/WARNINGS/ADVISORIES

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