267
FXUS63 KPAH 081717
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
1217 PM CDT Mon Jul 8 2024

.KEY MESSAGES...

- The remnants of Beryl will impact the region beginning late
  Monday through Wednesday night. Tropical rains will be heavy
  at times, especially across southeast Missouri and southern
  Illinois. This could lead to some flooding issues developing.

- A few severe storms will be possible as well late Monday and
  again Tuesday afternoon. Damaging winds and a few tornadoes
  will be the primary hazards.

- Drying out and warming up back to typical mid-summer heat and
  humidity for the end of the work week into next weekend.

&&

.UPDATE...
Issued at 1216 PM CDT Mon Jul 8 2024

Updated Aviation discussion for the 18z TAF issuance.

&&

.DISCUSSION...
Issued at 220 AM CDT Mon Jul 8 2024

Our two main weathermakers for the next few days are in clear
view this morning. A longwave upper trough to our northwest
stretching from south central Canada to northwestern Mexico and
Hurricane Beryl making its approach on the Texas Coastal Bend.
Mid 70s dewpoints over Arkansas also mark the end of our
relative humidity respite of the last few days. Dewpoints today
should work into the mid 70s by midday as overall column
moisture increases amid southerly sfc-300mb flow pulling from
the mid south and the richer moisture around the core of Beryl.

By this afternoon sufficient instability should have built in,
coupled with weak upper level ascent for showers and storms,
particularly over southeast Missouri. By this evening closer
proximity of the upper trough, the leading upper jet and the
remnants of Beryl significantly increase large scale ascent over
the region as the richer tropical moisture moves into the
region. A cold front to the northwest of the storm track looks
to also serve as a focusing mechanism for initial showers that
become more widespread through the night. With PWAT values 2.2
to 2.4 inches even fairly weak showers will be very efficient
and most guidance keeps some degree of precip over our southeast
Missouri counties in rainfall from 06z Tuesday through the
completion of the storms passage. Poor mid-level lapse rates
limit instability, but if sufficient surface based CAPE can
form over the southeastern part of the CWA there will be a risk
for tornadoes/damaging wind on Tuesday given the favorable
kinematics. Overall, meager convective instability may limit
the highest level precip values but the combo of strong jet
ascent, frontogenetic forcing and the column moisture of a
decaying tropical cyclone has the potential to produce higher-
end flood threat if everything comes together. In collaboration
with surrounding offices will be issuing a flood watch for about
the western 2/3rds of the CWA. Have a fair amount of
uncertainty about the eastern row or two of counties but it
serves as a reasonable buffer to the highest QPF forecast and
most likely area to see persistent heavy rain. The better chance
of deep convection and heavier instantaneous rates supports the
idea of including them with this issuance.

After Beryl moves through our conditions should dry out and
become a bit more pleasant. We will be at or slightly above
seasonal norms but may catch another reprieve from the higher
end humidity, for at least a few days before it oozes back into
the area by the upcoming weekend.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1216 PM CDT Mon Jul 8 2024

For the 18z TAFs, isolated convection will continue to develop
across southeast MO this afternoon into early this evening. Some
of this activity may reach the vicinity of CGI, PAH, and EVV at
times before coverage wanes overnight. However, widespread
showers with embedded convection associated the the remnants of
Beryl will spread from SW to NE across the area Tuesday morning.

Rain will reduce vsbys to MVFR levels with cigs lowering to
MVFR as well at CGI, PAH, and MVN. Briefly lower vsby and cig
restrictions are possible under heavier thunderstorm activity.

S to SW winds at 6-10 kts will become light and variable
overnight. Winds will shift to the NE at 5-10 kts at CGI and
PAH Tuesday morning, while remaining variable at MVN, EVV, and
OWB.


&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Flood Watch from late tonight through Wednesday morning for
     ILZ075>078-080>094.
MO...Flood Watch from late tonight through Wednesday morning for
     MOZ076-086-087-100-107>112-114.
IN...Flood Watch from late tonight through Wednesday morning for
     INZ081-085-086.
KY...Flood Watch from late tonight through Wednesday morning for
     KYZ001>008-010-014-018.

&&

$$

UPDATE...DWS
DISCUSSION...JGG
AVIATION...DWS