textproduct: Louisville

KEY MESSAGES

* Areas of frost are expected tonight, with freezing conditions possible (40-50% chance) in rural, low-lying areas in northern Kentucky and southern Indiana. A more widespread freeze is forecast tomorrow night.

* Overcast skies and patchy drizzle today will give way to dry but cool weather over the weekend. Temperatures will return to the 60s early next week.

DISCUSSION

Issued at 305 AM EST Fri Nov 6 2026

Early Friday morning, a cold front was draped from roughly St. Louis, Missouri to Muncie, Indiana. With and behind the front, low clouds and patchy drizzle have been observed, along with an uptick in winds which have sporadically gusted over 20 mph from the north- northwest.

*** CLOUDY WITH PATCHY DRIZZLE TODAY ***

The aforementioned front and its attendant gloomy weather will arrive early to mid morning from northwest to southeast, and linger into the evening across much of the area. This will keep daytime temperatures on the cool side; forecast highs range from the low 60s across the Lake Cumberland Region to the mid 50s north of I-64. Time heights suggest saturation is mainly above 1,000 ft which lowers confidence in any drizzle particularly during the afternoon, but certainly can't rule it out as the RAP shows some transient visibility reductions along with modest negative omega (rising motion) along the front.

*** FROST AND FREEZE THIS WEEKEND ***

Some uncertainty remains in when the back edge of the stratus will shift out of the local area, but the latest REFS probabilities for cloud cover drop quickly from north to south between 8pm and 2am EST. This will foster efficient radiational cooling tonight, particularly near and west of the I-65 corridor where winds should go calm as surface high pressure settles in. As a result, I elected not to deviate from NBM's forecast temperatures which are running on the low end of model guidance and depict Saturday morning lows anywhere from the upper 30s in the heart of the Louisville Metro to mid 30s over southern Kentucky to around 30 in rural, low-lying areas (1) west of I-65 and (2) in the northern Bluegrass. Given the uncertainty on when skies clear and winds go slack, didn't feel confident enough to issue a Freeze Warning for any part of our area for tonight, though again freezing temperatures are a distinct possibility in rural valleys. It's noteworthy that trying to quantify the probability is a bit tricky in this case, since virtually zero REFS members have temperatures < 33, while NBM's calibrated guidance suggests chances are as high as 70-80+% in spots; given REFS has been a few degrees too warm on overnight lows recently, we're going to lean towards NBM, but still think it's chances might be at least slightly overdone. Nonetheless, confidence is high (>80%) in frost nearly everywhere (save perhaps downtown Louisville, where the urban heat island may keep temps in the upper 30s); accordingly, we've issued a Frost Advisory, which is in effect from midnight to 9am EST tomorrow morning.

Confidence in a true freeze is higher (60-80%) tomorrow night into Sunday morning, as night-long clear skies and calm winds cause temperatures to sink like a rock. However, we elected to hold off on a Freeze Watch for now for simplicity sake.

Conditions will remain seasonably cool through the weekend, but temperatures should take a turn for the warmer early next work week as upper level ridging returns to yield highs solidly in the 60s Monday through Wednesday. Given the dry airmass, chilly, crisp mornings will continue with patchy frost possible each day, but after the widespread freeze Saturday night (and possibly again Sunday night over the Bluegrass) we don't think the corresponding headlines will be required again until spring.

Looking at EOF patterns for 500mb height in the LREF, uncertainty is high primarily in the east-west "zonal" position of a broad upper level trough expected to dive southeast out of Canada during the latter portion of the week. Two general scenarios have emerged from cluster analysis: outcome (a), favored by ~60% of guidance, would bring a few showers to the area Thursday-Friday followed by a cooldown next weekend; outcome (b) (40% chance) would keep us dry and mild, as the cooler air remains locked up across the Great Lakes and New England.

AVIATION /12Z TAFS THROUGH 18Z SATURDAY/

Issued at 621 AM EST Fri Nov 6 2026

An area of MVFR stratus, already at KHNB and SDF, continues to march east this morning, and should arrive at the remaining airfields by 14z. There is a low chance that brief IFR ceilings materialize alongside reduced visibilities in patchy drizzle, as sporadic upstream observations have had this morning. However, ceilings should be on rising trend once the sun comes up which suggests if it were to happen, it'd be most likely at HNB (30% chance) before 15z. Winds will blow from northwest around 8-10 kt with sporadic gusts to 15 kt during the afternoon. Stratus will gradually shift south behind the cold front this evening into tonight, bringing a return to predominant VFR conditions.

LMK WATCHES/WARNINGS/ADVISORIES

KY...Frost Advisory from midnight EST /11 PM CST/ tonight to 9 AM EST /8 AM CST/ Saturday for KYZ023>043-045>049-053>057- 061>067-070>074-076>078. IN...Frost Advisory from midnight EST /11 PM CST/ tonight to 9 AM EST /8 AM CST/ Saturday for INZ076>079-083-084-089>092.