textproduct: Louisville

KEY MESSAGES

* Seasonably mild weather will kick off the week with highs generally in the 70s through Tuesday. Many locations will climb back into the 80s Wednesday through Saturday.

* Overnight low temperatures may fall into the upper 30s in low- lying rural areas Monday night, but the probability of frost is low.

* Mild-moderate drought conditions, worst over southern Kentucky, will worsen this week as dry weather prevails. The next (40-60%) chance for beneficial rainfall will arrive late Saturday into Sunday.

DISCUSSION

Issued at 127 PM EDT Sun Oct 4 2026

*** MILD START TO THE WEEK, PATCHY FROST(?) MONDAY NIGHT ***

In the wake of a shortwave trough pivoting from the Great Lakes into the Northeast, mild conditions continue across the local area with temperatures in the low to mid 70s early Sunday afternoon. We'll likely add another 1-3 degrees before cooling into the upper 40s to low 50s tonight. Surface high pressure will move from Illinois to Ohio tomorrow, settling over the Appalachians tomorrow night. While it's to our north during the day, we'll have enough of a gradient to favor a cool northerly breeze around 5-15 mph - confining temperatures to the low-mid 70s - but tomorrow night winds should ease, particularly over northeastern portions of the area (closer to the high pressure center). With few, if any, clouds around, conditions will be favorable for radiational cooling - allowing temperatures to fall into the the low 40s if not upper 30s in the typical cold-prone, low-lying rural areas. If winds really drop off, there may be a field or two that see frost, but NBM suggests temperatures cold enough for this to happen (usually <37 degF) are unlikely (less than a 5% chance) for most.

*** SLIGHTLY WARMER, REMAINING DRY INTO SATURDAY ***

With such a cool start to the day and continued weak easterly flow, Tuesday will be another seasonably cool day with afternoon highs generally in the mid 70s, though a few locations over southern Kentucky may approach 80. We remain south of the main jet stream the remainder of the work week, while the dry airmass allows for deep mixing each afternoon. As a result, temperatures will warm just a smidgen for Wednesday through Friday; forecast highs are in the low to mid 80s (warmest south), while overnight lows will range anywhere from the mid 40s to mid 50s each day. The only concern during this period will be worsening and expanding drought conditions across the state, with D1 (moderate drought) observed from Ohio to Monroe Counties and points southwest, and D0 (abnormally dry) covering much of the rest of the county warning area (CWA) on last weeks' update from the US Drought Monitor.

*** TROPICAL REMNANTS TO BRING BENEFICIAL RAIN(?) BY SUNDAY ***

Looking ahead to the coming weekend, our attention rests on a disturbance over the southwestern Gulf. The National Hurricane Center (NBC) has given this feature a 30% of development into a Tropical Cyclone (TC) over the next 7 days, suggesting confidence is low on what will happen. However, if the solution currently depicted by both the deterministic GFS and ECMWF (i.e., southwest flow over the Mississippi Valley lifts this feature north into our neck of the woods) materializes, we could see beneficial rainfall by the second half of the weekend. This is a low confidence scenario, given uncertainty about (a) the formation of a tropical system, (b) the movement of that system, and (c) how it interacts with an incoming trough from the west, the timing of which remains unclear per cluster analysis. Consequently, member low locations in both GEFS and EPS (European Ensemble) vary drastically in timing and track of this tropical feature. However, NBM probabilities for more than 1 (2) inches of rainfall for the 48-hour period ending at 8am Monday morning are currently sitting at 30-45% (15-20%) - suggesting beneficial rainfall could aid the developing drought. Stay tuned.

AVIATION /18Z TAFS THROUGH 00Z TUESDAY/

Issued at 127 PM EDT Sun Oct 4 2026

Surface high pressure will favor VFR conditions through the flight period, though patchy fog can't be entirely ruled out tonight at RGA (10-15% chance). Generally light winds will blow from the north- northeast through tonight, then increase to around 10 kt tomorrow afternoon.

LMK WATCHES/WARNINGS/ADVISORIES

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