140
FXUS63 KLMK 041127
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
627 AM EST Wed Nov 4 2026

.KEY MESSAGES...

* Widespread rainfall tonight into Wednesday will benefit the
  ongoing drought. Amounts of 1 to 2 inches will be most common,
  though a few locations (10% chance) may see totals surpass 3
  inches. The risk of flooding is low but nonzero.

* The risk for severe weather is also low, though sporadic and
  localized gusty winds exceeding 40 mph may (20-30% chance)
  accompany heavier showers today.

&&

.DISCUSSION...
Issued at 253 AM EST Wed Nov 4 2026

At 245am EST Wednesday morning, a large upper level trough was
spinning over the Midwest, with its associated 1000mb surface low
positioned along the IA/MN border. Ahead of this low, deep southerly
flow is pulling rich Gulf moisture northward across the Ohio Valley
and Great Lakes Regions, with PW values of 1.5-1.8 inches along and
west of the I-65 corridor in Kentucky and southern Indiana. As this
low lifts north into the Upper Midwest today, its attendant cold
front will gradually traverse the local area. Ahead of this front,
gusty winds and heavy rainfall are concerns; behind it, winds will
ease and rain come to an end, though clouds will linger the
remainder of the day.

*** GUSTY WIND POTENTIAL ***

Scattered showers were percolating across the area as a low level
jet (LLJ) promotes isentropic upglide. A somewhat stable planetary
boundary layer (PBL) should in general limit the transfer of
momentum from the 50-55 kt winds clocked on KLVX`s vad at 1km (~3200
ft) AGL, though sporadic gusts to 30+ mph (recently observed at SDF)
may continue through dawn. Thereafter, various REFS members suggest
a heavier band of showers will develop along the eastward-meandering
cold front. REFS ensemble mean brings gusts to 30-40 mph with this
wave of rain, and even gives 15-30% (highest south) chances for
gusts over 40 mph between roughly the I-65 and I-75 corridors in
Kentucky during the 8am to noon EST timeframe. It would make
meteorological sense that this would be our best opportunity for
those stronger wind gusts, as (1) winds aloft will remain strong
during this time and (2) these heavier showers will feature the
strongest downdrafts. Still, given widespread clouds and rain
showers, low levels are forecast to remain somewhat stable, limiting
mixing on the whole and keeping the coverage and duration of those
stronger gusts low.

*** HEAVY RAIN POTENTIAL ***

In addition to gusty winds, widespread rainfall ahead of the front
today should benefit the ongoing drought. The near-record PW values
approaching 1.8 inches coupled with a 10-12 kft deep warm cloud
layer suggests showers ahead of the front will be efficient rain
producers with hourly rates approaching an inch at times. In
addition, the orientation of mean cloud layer winds nearly parallel
to the (slow-moving) cold front suggests training of heavier
showers, which could allow some locations to see 3+ inches of
rainfall in just a 6 hour period. REFS LPMM suggests this is most
likely along and west of roughly the I-65 corridor, especially south
of E-town where NBM maintains 10-30% probabilities (for 3+ inches).
This would imply a nonzero (but still low) risk for flooding in
urban and poor drainage areas, especially if any leaves clog storm
drains. However, most locations are expected to see between 1 and 2
inches of rainfall, which is much needed.

The cold front will bring an end to the rain and gusty winds from
west to east today, reaching I-65 around 1-2pm and the I-75 corridor
around 5-6pm EST. Behind it, however, we`ll hang onto clouds and may
even see some patchy drizzle this evening into tonight.

*** EXTENDED PERIOD ***

Conditions will turn drier on Thursday and we may even see some
breaks of sunshine during the afternoon ahead of the next shortwave
trough which will pass through the Lower Great Lakes on Friday. The
LREF suggests a 40-70% probability 850mb temps drop to sub 0 degC
near and north of an Owensboro to Richmond line Friday into
Saturday, which indicates our area will be cool to kick off the
weekend. In fact, forecast highs are in the mid 50s for Saturday -
much more seasonable for early November. Clouds Friday night should
keep lows from falling too far, but Saturday night we may see some
frost or even localized freezing conditions (particularly over the
Bluegrass) as clear skies and light winds make for efficient
radiational cooling. Continued northwest flow will maintain dry and
seasonably cool conditions into early Monday, with a gradual warming
trend next work week.

&&

.AVIATION /12Z TAFS THROUGH 18Z THURSDAY/...
Issued at 626 AM EST Wed Nov 4 2026

Scattered showers will continue over the area the next several
hours, bringing occasional ceiling and especially visibility drops
into the low MVFR or IFR category. Meanwhile, a wave of heavier
rain, locally gusty winds to 30 kt, and perhaps (10-20% chance)
a lightning strike or two will work through the area from west
to east during the 14-19z timeframe. Even outside of these
gustier showers during the late morning-early afternoon, winds
will be gusting over 20 kt at times from the south. Once the
showers clear the area during the afternoon, winds will switch
around to the southwest and drop off dramatically. We may have
some patchy drizzle behind this front as MVFR ceilings linger
into the evening, especially at LEX/RGA.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.

&&

$$

DISCUSSION...JRB
AVIATION...JRB