761
FXUS63 KPAH 241737
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
1237 PM CDT Mon Jun 24 2024

.KEY MESSAGES...

- After a welcomed respite from the oppressive heat/humidity
  today, Heat indices threaten to approach or exceed 105 degree
  Advisory levels Tuesday.

- A cold front`s Tuesday night approach and Wednesday passage
  will bring a chance for strong to potentially severe storms
  with it.

- Another respite from the heat and humidity comes Thursday
  before temperatures and heat indices start to bump up again by
  week`s end.

&&

.DISCUSSION...
Issued at 240 AM CDT Mon Jun 24 2024

The recently passed frontal boundary is now to our south/east and it
has drawn down dew points and taken most/if not all the 70+ dews
with it. They may linger and hover over our southern and western CWA
borders today, but should not rise much/if any further, while in our
north, there may be yet another 2-3 degree drawndown into the mid
60s over the course of the day. This will improve the apparent
temperature for most with still toasty highs in the lower half 90s
today. The exception will be the Ozarks, where a few 100 degree Heat
Indices are not entirely out of reach.

Surface high pressure shifts eastward tonight and with the gradient
pivot, return flow south to southwesterlies will initiate and begin
to increase dew points and temperatures heading into and thru the
day Tuesday. That`ll end up being our warmest and most uncomfortable
day of the past several, with the models consistently hammering 22C
H8 temps and highs in the mid-upper 90s as dew points return to the
low-mid 70s over at least our western half of the CWA. That
translates to Heat Indices reaching into the triple digits over most
of the FA, with our western half seeing Advisory level 105s
approached or just exceeded. This too has been a consistent
signal so after collaboration, we`ll go ahead and issue a Heat
Advisory for Tuesday afternoon for all counties along and west
of the MS River.

The next cold front takes shape and approaches with its attendant
convection late Tuesday night, poised for a daytime Wednesday
passage. As height falls begin Tuesday night, and the front drops
this direction, an active/ongoing MCS to the north drops with it,
and spreads Pops but also its blow-off convective cloud shield into
our CWA. Bulk shear increases into the 25-30 kts range, but lapse
rates are challenged at about 5C/KM. All said, the anticipated
Marginal risk has materialized for our northern CWA counties, with
emphasis on marginal given its late night arrival. And
similarly, while the cloud shield`s lay-out may muddy up our
ability to destabilize with daytime heating Wednesday (modeled
MUCAPEs are detained AOB 2000 Joules for the most part), the
passage of the upper trof and reflected surface front should be
enough to overcome the still retardant lapse rates of 5-6C/KM
and cloud hampered surface heated instability to fire up
convective chances again, including what`s probably going to be
at least another Marginal risk translated with the front across
the remainder of our CWA as it makes its passage. High PW`s
support heavy rain potential as well, so we concur with WPC`s
continued Marginal risk of exceeding FFG until the front clears.

After fropa, CP high pressure from Canada draws in refreshingly
cooler and drier air for Thursday. Highs will be in the mid to upper
80s, but dew points will drop thru the 60s and the model trends for
50s dew points are increasing, at least for our northern counties.
The high shifts to the east Friday, but the 60s dew points hold
another day, even as temps return to near normal highs around 90.
This commences the week ending warmup, with low-mid 90s slated for
Saturday as 70 degree dew points reemerge at least in our south.
Another fropa over the weekend could limit that to just the first
half of the weekend, however, as we return closer to seasonal norms
again for day 7.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1237 PM CDT Mon Jun 24 2024

The TAFs are VFR. Southwest winds may gust 15-20kts at times in
the late morning at the northern sites.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Heat Advisory from noon to 8 PM CDT Tuesday for ILZ080-084-088-
     092-093.
MO...Heat Advisory from noon to 8 PM CDT Tuesday for MOZ076-086-087-
     100-107>112-114.
IN...None.
KY...Heat Advisory from noon to 8 PM CDT Tuesday for KYZ001>004.

&&

$$

DISCUSSION...SP
AVIATION...DRS