619
FXUS63 KLMK 161101
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
701 AM EDT Sun Jun 16 2024

...Updated Aviation Discussion...

.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 through
    Tuesday, then dry from Wednesday into next weekend.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 330 AM EDT Sun Jun 16 2024

Today, an upper ridge remains over the eastern CONUS while a closed
upper high sits over the Southeast. At the surface, a surface high
will get pushed, by the upper ridge, through New England before
reaching the coast. This will cause easterly winds over the CWA to
veer towards the south before continuing to the southwest. This
southern component of the low level flow will really begin to funnel
Gulf of Mexico moisture into the Ohio Valley.

By midday, precipitable water values of over 1.5" will begin
entering the CWA from the southwest. This low level moisture is
expected to produce cumulus over the region this evening, and as
some disturbances work around the upper high, this could kick off a
few isolated to scattered thunderstorms, mainly across south central
Kentucky. Some subsidence in the mid-levels could limit thunderstorm
growth. Heavy rain, lightning, and gusty winds will be possible, but
most will just experience a hot sunny day as coverage will be
limited. The warm air advection will help mostly sunny skies lift
highs into the low to mid 90, and with dew points in the mid 60s to
around 70, heat indices will climb into the mid to upper 90s. A
couple sites could reach 100. The best chances will be across the
western half of the CWA.

Tonight, southern winds will ease as precipitation chances decrease.
Skies will remain partly cloud. Lows are expected to drop into the
upper 60s to mid 70s.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 330 AM EDT Sun Jun 16 2024

Hot temperatures are expected through the week as anomalously strong
upper ridging remains anchored over the eastern CONUS. Monday and
Tuesday will be more of our traditional Ohio Valley heat, as the
ridge is centered mainly over Virginia and the Carolinas. Deep
southerly flow into the Ohio Valley will keep dewpoints near 70, and
support mainly diurnal showers and storms, though coverage will only
be isolated to widely scattered. Will carry 20-30% POPs each
afternoon.  Temps will reach the lower-mid 90s, with heat index
values near 100.

Wednesday through Friday, the strengthening East Coast ridge takes
on more of an east-west orientation, resulting in height rises and
mid-level subsidence over the Ohio Valley. This will keep a lid on
convection, and allow temps to climb into the mid/upper 90s. Still
not going too crazy with the heat index, as the warming will be
offset by dewpoints dropping into the lower 60s by Thu-Fri. It`s
nothing you`ll mistake for the desert, but just enough to take the
edge off the heat.

Rain chances return to southern Indiana next weekend, as the ridging
starts to show weakness across the Great Lakes. POPs still only
around 20 percent, and even less across Kentucky, but we`ll keep an
eye on that for some break in the heat and potential developing
drought.

Confidence in reaching triple-digit heat indices is not high enough
for even a duration-based Heat Advisory. However, a prolonged period
of hot temperatures is very likely to cause societal impacts, so we
will ramp up messaging to core partners and be prepared to go with a
Heat Advisory if confidence in broader impacts increases.

&&

.AVIATION /12Z TAFS THROUGH 18Z MONDAY/...
Issued at 701 AM EDT Sun Jun 16 2024

VFR conditions are expected through the forecast period. Light winds
will continue veering towards the south to southwest this morning.
Skies will remain mostly clear until later this evening when cumulus
is expected to develop. A few isolated storms are possible. Chances
are low this will impact a forecasted TAF site, so this chance was
left out of the TAFs.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...Air Quality Alert until midnight EDT tonight for KYZ029>031.
IN...Air Quality Alert until midnight EDT /11 PM CDT/ tonight for
     INZ076>079-083-084-089>092.

&&

$$

SHORT TERM...KDW
LONG TERM...RAS
AVIATION...KDW