266
FXUS63 KPAH 232326
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
626 PM CDT Sun Jun 23 2024

.KEY MESSAGES...

- Less humid air works into the region tonight through Monday. Still
  hot on Monday (low 90s) but it won`t feel near as oppressive.

- Heat and humidity will increase Tuesday with heat index values of
  100 to 107.

- Shower and storm chances return Tuesday night through Wednesday as
  a cold front moves through. A few severe storms are possible.

- Thursday will offer a brief break from the heat and humidity
  before it returns Friday into Saturday.

&&

.UPDATE...
Issued at 626 PM CDT Sun Jun 23 2024

Updated aviation discussion for 00Z TAFs.

&&

.DISCUSSION...
Issued at 231 PM CDT Sun Jun 23 2024

A frontal boundary is pushing south through the area this afternoon.
Low level moisture is pooling along it, resulting in some of our
highest dewpoints so far this summer (mid to upper 70s). Have yet to
see much convection develop along the front, but there is certainly
plenty of instability (MLCAPE 2500-3000 j/kg) to ignite some
isolated activity across west KY before the boundary sinks south
into TN by early evening. Heat index readings have exceeded 100
across much of west KY and southeast MO, and a few locations are
even pushing 105.

Surface high pressure will descend across the area tonight through
Monday, resulting in a much drier airmass with dewpoints dropping
into the low to mid 60s. Plenty of sun will help boost highs
back into the low 90s on Monday, but with the lower humidity the
heat index will largely remain in the low to mid 90s. The
exception is the Ozark Foothills of Missouri which could sneak
closer to 100.

500mb heights rise slightly on Tuesday along with an uptick in 850mb
temps (around 22C). This will result in highs reaching the mid to
upper 90s. Southwest winds will also advect in higher moisture with
dewpoints reaching the lower 70s. This bumps are heat index
into the 100 to 107 range. A Heat Advisory may be needed for at
least a portion of the region on Tuesday.

Tuesday night into Wednesday continues to look rather unsettled as
another cold front makes passage across the Quad State. 0-6km bulk
shear looks to be at least 25-30 kts, and may even exceed 35 kts
according to the 12z GFS/Canadian. Could see an MCS dive into part
of the area Tuesday night into Wednesday morning, with additional
activity possibly firing during the heat of the day on Wednesday.
The overall parameter space could support some severe storms during
this time period. The CSU-MLP continue to depict some 5% severe
probs for us, while keeping the higher threat to our north through
Tuesday night and then further east on Wednesday.

The 12z model suite is even more pronounced with our cooler and
drier airmass on Thursday. Dewpoints likely will at least fall into
the lower 60s and may even dip into the 50s for some of our cwa.
Highs are only expected in the mid to upper 80s. Unfortunately this
cooler spell will be brief as 500mb heights rise again Friday into
Saturday resulting in highs returning to the 90s. Humidity levels
rise some on Friday but may not be too oppressive again until
Saturday. We could see a return of mid 70 dewpoints as moisture
pools ahead of another frontal boundary on Saturday.

Model guidance continues to advertise another front diving into
the region next weekend. Today`s model runs are faster with it,
which would favor Saturday into Saturday night being our main
chance for showers and storms as opposed to Sunday. The NBM is
slow to latch onto this, so our current forecast still has
higher PoPs on Sunday. Since its still 6-7 days out it could
very well slow down again so kept the NBM for now. Precipitable
water values look to exceed 2 inches, and may even approach 2.5"
if the ECMWF is to be believed. Certainly could have some
torrential rainfall during this time period.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 626 PM CDT Sun Jun 23 2024

VFR conditions should prevail over the next 24 hours with light
and variable winds and mainly clear skies. There`s still a small
chance of patchy fog overnight, especially in western Kentucky
near the Tennessee border. However, the drier air moving in
behind the front should largely prevent its formation.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.

&&

$$

UPDATE...RJP
DISCUSSION...SP
AVIATION...RJP