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KEY MESSAGES

* Cooler temperatures are expected tonight, but milder air returns by Monday afternoon.

* Off and on chances for light rain showers are expected Monday afternoon through much of the week. Precipitation amounts are expected to be light.

* Unseasonably warm temperatures are likely around Christmas, with highs in the 60s to around 70 likely from Christmas Eve through Friday.

* Mild weather continues into the first part of the weekend, but will gradually trend cooler by Sunday with a series of reinforcing cold fronts. Off and on rain chances will also accompany these frontal passages.

SHORT TERM /THROUGH MONDAY/

Issued at 254 PM EST Sun Dec 21 2025

Quiet conditions continue across the area, with highs peaking around seasonally normal values of 45 to 50 degrees, maybe slightly above. Variable mid and upper sky cover will continue late afternoon through early evening, before mostly clear skies take hold tonight. The center of surface high pressure will slide just to our north this evening, and then center over the mid Appalachians spine by sunrise on Monday. Although light ESE winds will begin to take hold toward sunrise, many areas will remain decoupled, especially valleys. The end result will be a pretty good radiational cooling night with some cold lows in the 25 to 30 degree range for many. There will be much colder spots that are more typically decoupled in this scenario that will probably settle more around 20 degrees for a low. After all, dew points will be in the upper teens, so fully expect a colder KY Mesonet site or two to find values that low, especially across our eastern CWA.

As the surface high continues to shift east toward the mid Atlantic Coast on Monday, our pressure gradient tightens a bit with southerly flow taking hold by afternoon. We'll also see some modest isentropic lift begin to take hold across our western CWA as a low level jet slowly ramps up through the day. Will keep low chances for a measurable light rain along and west of I-65 from 20 to 00z Monday. Look for mild highs in the low and mid 50s.

LONG TERM /MONDAY NIGHT THROUGH SUNDAY/

Issued at 254 PM EST Sun Dec 21 2025

Monday Night - Tuesday Night...

Some pockets of light rain will likely already be ongoing along and west of I-65 by sunset Monday night. This light precipitation will then spread eastward through the night across the entire CWA as isentropic lift with good low level jetting provides the proper ingredients for at least some measurable rainfall for most, if not all. That being said, this would be considered a high POP, low QPF type of event where amounts look to remain a tenth of an inch or less. The best of the low level jet core will be in place overnight, however it is only slow to diminish through Tuesday, so will keep lingering chance pops in here mainly across southern and eastern portions of the CWA. Light rain chances will likely continue to linger into Tuesday night across the southern half of KY, where a cool frontal boundary looks to stall out parallel to the upper flow. Better confidence that southern IN and northern KY are on the dry side of the boundary by this time.

Temperatures in this early week portion of the forecast will be on the milder side as low in the mid 40s to low 50s look to be a reasonable bet each night. The current forecast calls for highs in the mid 50s to around 60, but given heavy cloud cover and lingering light rainfall, wondering if a 10 to 12 degree diurnal rise is a bit too aggressive?

Christmas Eve - Christmas Night...

We'll be keeping some light rainfall chances for Christmas eve across the area, possibly lingering into our NE on Christmas morning. The stalled frontal boundary from early week will begin to lift north as a warm front as weak surface low pressure develops over the central Plains and upper ridging builds over the south central CONUS. Low level jetting fires up again over top this poleward retreating warm front, and will allow for more pockets of light rainfall. Not expecting a washout or a lot of liquid. Likely more of a trace to a few hundredths of measurable rain. By later into Christmas Day and Christmas night, warm front should be lifting out of the NE CWA, with dry conditions more likely for the CWA. Shorts and flip flops might be a good last minute gift idea as highs on Christmas Day look to range in the 65 to around 70 degree range.

Friday - Sunday...

We'll keep small chances for rain in the forecast through the weekend, along with mild Friday and Saturday temperatures stepping down to more seasonally normal highs in the 40s by Sunday. This will occur thanks a series of passing cold fronts, the second of which looks to be more notable. Models have come into better agreement on the timing/placement of a system passing through the Great Lakes region Saturday night into Sunday, with the trailing cold front sparking some shower activity along and ahead of it over our region. The 21/12z ECMWF, which has occasionally shown a slower and more aggressive solution has come back on this particular run. In this scenario, a better chance for strong gusty winds and perhaps a line of stronger thunderstorms would come into play late Saturday night into Sunday morning. Something to continue keeping an eye on until better agreement in strength of that system becomes clearer. Clean passage should be complete during the day on Sunday with dry and colder conditions overtaking from W to E through the day.

AVIATION /00Z TAFS THROUGH 06Z TUESDAY/

Issued at 633 PM EST Sun Dec 21 2025

VFR conditions tonight with a light northeast wind veering from the east. VFR conditions are also likely to continue through 18Z Monday, with only some SCT-BKN high clouds spreading across Monday morning. Winds will continue to veer from the southeast Monday morning and increase through the mid to late morning hours.

Lower ceilings will develop across the region from the SW after 18Z Monday, with MVFR ceilings increasing likely at the three western terminals (HNB, BWG, SDF) by 21-00Z. Winds will continue to veer around from the south Monday afternoon. Spotty, light rain looks possible late in the TAF period, mainly after 21Z. However, the probability for rain (20%) is too low to include in the TAF at this time.

LMK WATCHES/WARNINGS/ADVISORIES

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