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FXUS63 KLMK 171555
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
1155 AM EDT Mon Jun 17 2024

.KEY MESSAGES...

*   Persistent early season heat wave expected, with highs well into
    the 90s each day.

*   Heat index values not expected to reach advisory levels, but
    societal impacts are likely.

*   Spotty coverage of afternoon thunderstorms today and Tuesday,
    then dry Wednesday through Saturday, with flash drought
    development possible.

&&

.UPDATE...
-- Changed Discussion --
Issued at 1154 AM EDT Mon Jun 17 2024

Very warm, humid conditions are in place this morning beneath
strengthening ridging aloft. A subtle upper level shortwave trough
will lift north over the MS River Valley today into the Lower OH
Valley. In addition, the rich low-level moisture in place will allow
us to easily reach convective temps in the lower 90s. Sparse
convection is still expected to develop during the afternoon and
evening hours. The environment will become moderately unstable with
> 2000 J/kg MLCAPE and strong DCAPE (> 1000 J/kg). A few individual
storms could grow tall enough to produce locally gusty winds and
brief torrential rainfall. But convection will remain very spotty,
and most of the day will be mainly dry and hot with peak heat
indices topping out near 100 degrees.
-- End Changed Discussion --

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 326 AM EDT Mon Jun 17 2024

Upper ridging remains over the eastern United States while a
surface high sits off the New England coast. High pressure ridging
extends from the high`s center towards the southwest into the
Carolinas. This is keeping southerly wind over the Lower Ohio
Valley. It continues to funnel Gulf of Mexico moisture up the
Mississippi Valley into the Ohio Valley.

Today should be a lot like yesterday, but now the moisture that
worked in yesterday is already here. Precipitable water values will
remain between 1.5-2" over most of the the CWA. Values could drop
just under 1.5" in parts of the Lake Cumberland and Bluegrass areas.
Farther to our west, over western Kentucky, PWATs climb over 2".
That`s a lot of moisture, but warm temperatures can hold a lot of
moisture. Looking at model soundings, the low levels look well
mixed, so even with good instability and moisture, believe the
showers and thunderstorms will be fairly limited today as mid-level
subsidence remains. Lots of sunshine and warm air advection will
lift temperatures back into the low to mid 90s. With dew points in
the upper 60s to low to mid 70s, heat indices will cross the 100
degree mark in some areas. Due to this, a Special Weather Statement
will be issued again today.

Tonight, southern winds will ease as precipitation chances decrease.
Skies will remain partly cloud. Lows are expected to drop into the
low to mid 70s.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 326 AM EDT Mon Jun 17 2024

Anomalous upper ridge will continue to strengthen along the East
Coast Tuesday, as it drifts north from the Carolinas into Virginia.
By Wednesday the ridge axis becomes oriented more east-to-west into
the Ohio Valley. As a result most of the week will be hot and dusty,
with precip chances barely touching 20 percent Tuesday afternoon and
dropping off from there.

Temps each day will climb well into the 90s, but with dewpoints only
just touching 70 on Tuesday and dropping off into the lower/mid 60s
later in the week, heat index values will be largely held in check.
Best chance for the heat index to touch 100 will be Tuesday, and
again Thu-Sat as air temperatures climb into the upper 90s. This
heat wave will be most notable for its persistence. No heat-related
headlines are planned at this time, but will ramp up messaging to
core partners as societal impacts are quite possible.

Small rain chances return on Sunday as the upper ridge breaks down
just enough for a cold front to approach the region. At this point
precip chances are no more than 30 percent, with minimal relief in
terms of temperatures.

&&

.AVIATION /12Z TAFS THROUGH 18Z TUESDAY/...
Issued at 707 AM EDT Mon Jun 17 2024

The forecast remains on track. VFR conditions are expected to last
through the forecast period. With the moist airmass overhead, a low
chance of precipitation remains through the period. The highest of
the low chances will be during the afternoon and evening hours.
There will likely be some isolated convection during the day, but
chances remain too low to include it in the TAFs. Continued
southerly winds are expected to be a little more gusty during the
afternoon hours.

&&

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

&&

$$

UPDATE...EBW
SHORT TERM...KDW
LONG TERM...RAS
AVIATION...KDW