LMK issues Area Forecast Discussion (AFD) at Jul 1, 7:50 PM EDT851
FXUS63 KLMK 012350
AFDLMK
Area Forecast Discussion
National Weather Service Louisville KY
750 PM EDT Wed Jul 1 2026
.KEY MESSAGES...
* Hot and humid conditions continue through the end of the week and
into the Independence Day holiday. Afternoon temperatures warming
the low-to-mid 90s and heat indices between 100-115 combined with
limited nighttime cooling will lead to adverse heat-related
impacts if precautions are not taken.
* We will see the increase of afternoon storm chances as we head
into the holiday weekend bringing localized flash flooding and
gusty winds in some areas.
* Humidity remains high into next week with slight heat relief from
a weakening ridge and afternoon rain through midweek.
&&
.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 227 PM EDT Wed Jul 1 2026
We remain locked in under a strong upper level ridge through the
short term period with very hot and humid conditions continuing into
tomorrow. Temperatures this afternoon are a few degrees warmer than
they were at the same time yesterday. Dew points are in the
mid/upper 70s and the heat index values were between 100-105.
Excessive Heat Warning remains in effect through tomorrow and into
the end of the week. The forecast will remains relatively unchanged
as we go into tomorrow. The only noticeable change to the forecast
grids was to remove the chance of isolated convection tomorrow
afternoon keeping us dry and hot.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 227 PM EDT Wed Jul 1 2026
===== Friday - Mid Week =====
The overall synoptic pattern slowly shifts by the end of the week as
the upper level ridge begins to break down moving east over the Mid-
Atlantic. As this happens, the positioning along the west side of
the departing high will allow a surge of PWATs ranging 1.7-1.9" to
move in from SW flow. This will also allow any discrete small waves
or disturbance to move over KY, bringing in the chance for diurnally
driven storms to return.
Confidence remains low with storm chances in the afternoon, keeping
PoPs low. However, any sort of lift is all that is needed to
initiate storms in such a convective environment. HREF ensemble mean
SBCAPE values range well above 3,500 J/kg, though shear values are
expected to remain weak in the afternoon with the lack of any large
scale disturbances nearby. That being said, if anything causes
parcels to break the already weakening cap as the ridge axis moves
east, precipitation will likely come in the form of heavy, slow-
moving downpours from storms. This remains an isolated risk of flash
flooding and gusty winds, though with the latest flooding event KY
has went through, this is a trend to monitor. It is worth noting
that 50th percentile of rainfall from now until Saturday morning
remains <0.1", though other ensemble solutions are right-skewed
towards more than 0.5" in our far S/SW communities.
With high humidity in the air and elevated temperatures in the mid
90s, the Excessive Heat Warning will remain at least through
Saturday morning, though may be extended dependent on rain chances
for Saturday. Heat indices remain high on Friday in the 100-110
range still.
By Friday night, any lingering storms would likely rain themselves
out and most communities begin dry by Saturday morning ahead of an
incoming trough. Lows in the morning are still warm in the low to
mid 70s. To our north, the jet stream will be moving quick bursts of
disturbances over the Great Lakes. The greatest deal of uncertainty
with this weekend's forecast, especially for Independence Day, is
determining when it may rain. Should the ridge clear sooner and the
jet stream sink a little further south, then KY will be closer to
these fast moving shortwaves and multiple rounds of showers and
storms are possible. The opposite is true if the jet trends further
north. For now, scattered storms during the afternoon are possible,
bringing lightning, general gusty winds, and heavy downpours. A
Marginal Risk for excessive rainfall has been issued for our whole
area, indicating the risk of flash flooding should repeated rounds
of scattered storms occur. This set up does not support repeated
training storms as what occurred last weekend, though PWATs will
remain high so any downpour still poses a risk for flash flooding.
Highs on Saturday will depend on the coverage of afternoon storms
but will be in the low to mid 90 with heat index temperatures in the
afternoon in the upper 90s to mid 100s.
Heading into Sunday, we move into a more zonal pattern, which allows
for continued subtle shortwaves to move over the KY/southern IN
area. Daily rain chances from storms will linger through Tuesday as
our hot and muggy air mass won't change significantly. In fact,
synoptic winds will remain rather weak over central/southern CONUS.
Long range guidance is suggesting a cut off low at the surface will
meander its way across the Plains, keeping a weak moist southerly
flow in place. Daily rain chances will continue as long as the
location of the low nearby. Temperatures remain warm albeit with a
slight cooling trend by midweek.
&&
.AVIATION /00Z TAFS THROUGH 06Z FRIDAY/...
Issued at 748 PM EDT Wed Jul 1 2026
High pressure will foster continued light winds and predominantly
VFR conditions throughout the forecast period. The one exception
will be during the 08-12z timeframe when there is a low chance for
fog at BWG, LEX, and HNB; a tempo group has been added to account
for this.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...Extreme Heat Warning until 9 PM EDT /8 PM CDT/ Friday for
KYZ023>043-045>049-053>057-061>067-070>078-081-082.
IN...Extreme Heat Warning until 9 PM EDT /8 PM CDT/ Friday for
INZ076>079-083-084-089>092.
&&
$$
SHORT TERM...BTN
LONG TERM...BKF
AVIATION...JRB
Source:
LMK issues Area Forecast Discussion (AFD) at Jul 1, 7:50 PM EDT---------------
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