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KEY MESSAGES

* Weather systems will come together over the region Monday night into Tuesday morning, bringing mixed wintry precipitation in the forms of snow, sleet, freezing rain and rain as they come together over the Ohio Valley.

* Snow accumulations of 1 to 3 inches is likely across portions of the area, especially along and north of the WK/BG Parkways. Brief periods of freezing rain/sleet are possible, and a glaze of ice is possible before changing to snow.

* Impacts to travel conditions are likely Tuesday morning.

SHORT TERM /THROUGH TONIGHT/

Issued at 359 AM EST Mon Dec 1 2025

Main focus in the short-term is the impacts from the real first winter system of the season. Sfc high pressure will keep the first half of today quiet but also unseasonably cold. Temperatures already this morning were in the low/mid 20s with even a few isolated spots per the KYMeso in the upper teens. Sfc high will quickly push eastward during the day and be across over the NE US by this evening. A mid-level shortwave trough ejecting eastward out of the Rockies and through the central Plains later today will help to draw and advect warm Gulf moisture northward into the Ohio and Tennessee Valley forcing and lifting it over the colder layer near the surface. A developing weak sfc low will lift out of the western Gulf and across the SE United States late Monday night into early Tuesday morning. The interaction between these two system will result in widespread wintry precipitation over southern IN and central KY.

Light snow associated with the upper trough will work out of the Plains and spread into northern and central IL by Monday evening as precipitation associated with the WAA/moisture advection comes in from the south and across TN entering south central KY around the same time. By late Monday night and early Tuesday morning these two systems will come together over area with increased lift and forcing associated by the isentropic lift from the weak sfc low to the south and southeast and strong vorticity and from the approaching mid- level trough and being co-located with upper level divergence associated with the right entrance region of a 300mb jet streak.

Initial precipitation across southern KY should start off as rain, as it lifts northward into central and northern KY and southern IN, we will start to see a mix of snow, sleet and even a period of freezing rain as the warm air/moisture advection area works northward ahead of the upper trough axis. Current thinking remains that most of the wintry mix of sleet, snow and even some freezing rain falls along and north of the WK/BG parkways and to a certain extent, into parts of the Blue Grass along and north of I-64 and along and east of I-75. With mainly all snow falling along and north of the Ohio River into southern Indiana. At this time, we don't expect more than a light glaze of ice, especially on elevated and untreated surfaces as ground and sfc temperatures will be near or just above freezing. As the upper trough arrives, cold air aloft will advect in along with a strong mid-level vort max developing moderate to strong banding of snow over the area. Current forecast calls for snowfall amounts to range from 1 to 3 inches from the Parkways northward with potentially more associated with strong/heavier snow bands. Because of the potential snow amounts, along with a light glazing of ice, this being the first system to bring accumulating snow/ice of the season and that it will likely impact the Tuesday morning commute, went ahead and issued a Winter Weather Advisory for Monday night into Tuesday morning.

There are potential bust in this forecast with growing discrepancies between the hi-res short range models and the medium-long range deterministic models. Both the GFS and ECMWF have remain fairly consistent over the last couple of runs, with the more southern track of the sfc low and the phasing of the two system taking place over central KY with the main snow band setting up north of the parkways, consistent with our forecast over the past several days. On the other hand, the hi-res models of the NAM/HRRR delay the phasing of these two system ultimately pushing the main snow band further to the east and south. Potentially shift the main band of snow outside of the current Winter Weather Advisory. This would greatly reduce the snow amounts to the north and focus it more along and south of the WK/BG parkways than had been previously advertised over the past several days. There is also the challenge of the WAA advection and how far into do we get before the mid-level trough arrives across central KY and southern IN. This would also limit snow amounts as it would make the thermal profile too warm for all snow creating more rain and wintry mix instead reducing snow amounts. Either way, this system will bring minor winter weather associated impacts to the area, especially for the Tuesday morning commute.

LONG TERM /TUESDAY THROUGH SUNDAY/

Issued at 359 AM EST Mon Dec 1 2025

Weather turns quiet going into the middle of the week. Zonal flow aloft and sfc high pressure keeps the forecast mainly dry but also colder than normal with highs ranging from the mid/upper 30s to low 40s. A cold front is expected to move through between areas of sfc highs Wednesday night into Thursday morning but it will lack moisture outside of a few clouds.

Thursday night into Friday will feature a nearly identical setup to what we will see later tonight into tomorrow , as another shortwave upper trough ejects across the central CONUS, pulling a developing surface low northward out of the Gulf and into the TN/lower OH valleys. The cold air source ahead of this system does not appear to be as supportive of wintry weather as the one tonight, with the center of the sfc high shifting off the mid-Atlantic Coast. However, given the amount of lead time and potential shifts in the model guidance, we'll need to continue to monitor this system later this week for wintry weather potential. Forecast confidence decreases after Friday, though a general signal for additional disturbances swinging through the region later in the weekend is found in the medium-range guidance. A modest warming trend over the weekend should make it more likely that these systems end up being mostly/all rain. However, temperatures should remain below normal through next weekend.

AVIATION /12Z TAFS THROUGH 18Z TUESDAY/

Issued at 629 AM EST Mon Dec 1 2025

Stubborn stratus has started to build in from LEX to SDF and could see it push south towards RGA and HNB. Went more pessimistic for flight categories this morning. We will get a period late morning/early afternoon where we see high to mid clouds move in with VFR flight categories but that will be short lived as the next system will arrive later tonight. As rain and snow work in from the south and west CIGs will start to lower with mainly snow for HNB/SDF/LEX, mainly rain with a brief period of snow for BWG and rain to snow for RGA. Timing is very complicated as there remains some questions on where the heaviest snow band sets up overnight into early tomorrow morning

LMK WATCHES/WARNINGS/ADVISORIES

KY...Winter Weather Advisory from 10 PM EST /9 PM CST/ this evening to 9 AM EST /8 AM CST/ Tuesday for KYZ023>043-045>049-053- 061. IN...Winter Weather Advisory from 10 PM EST /9 PM CST/ this evening to 9 AM EST /8 AM CST/ Tuesday for INZ076>079-083-084- 089>092.