378
FXUS63 KPAH 010830
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
330 AM CDT Mon Jul 1 2024

.KEY MESSAGES...

- Anomalously dry air will make for a very pleasant day today,

- The heat and humidity will build quickly Tuesday and
  Wednesday, and possibly linger into Thursday. Triple digit
  heat indices are expected on Wednesday and possibly Thursday.

- Chances of thunderstorms return Wednesday and continue through
  the weekend. The best chances will be Wednesday night through
  Friday. A few severe thunderstorms cannot be ruled out
  Wednesday and Thursday. Heavy rainfall will also be possible.

- There is potential for a dry and relatively pleasant weekend,
  but 4th of July celebrations Wednesday through Friday may be
  impacted by thunderstorms.

&&

.DISCUSSION...
Issued at 330 AM CDT Mon Jul 1 2024

The ECMWF ensembles have a 30 year return interval on dry air at
850mb today, but then have the same interval for moist air at
850mb and 925mb Thursday. So, today will be the pick day of the
work week, with very low humidity and high temperatures in the
lower 80s, which is around 8 degrees below normal. Enjoy it
because the heat and humidity will return quickly.

South winds will return Tuesday, as high pressure aloft builds
over the Quad State. Humidity will increase and temperatures
will climb up to near 90 which is just above normal levels. The
heat and humidity will be right back up to near last Saturday`s
levels on Wednesday, which will likely require another Heat
Advisory for all or a portion of the region. If some portion of
the region is not significantly impacted by convection on
Thursday, heat indices could reach triple digits and possibly
advisory-levels again.

A short wave trough moving eastward across Ontario on Wednesday
may drag a weak, convectively-aided, surface boundary into
northern portions of the Quad State late Wednesday into
Wednesday night. Given the rather extreme heat and humidity
expected ahead of it, convection is a reasonable expectation.
However, the ridge is rather stout and may continue to suppress
convection until Thursday when another stronger trough makes
its approach through the Plains. This system will bring a cold
front through the area Friday, which would presumably bring an
end to the convective threat and the extreme heat and humidity.

Given the very unstable surface air mass, at least isolated
severe storms with a damaging wind threat will be possible,
despite rather marginal shear. Severe storms would be most
likely in the afternoon and evening Wednesday and Thursday.
Precipitable water values near 2" will lead to torrential
rainfall and possibly some flooding issues in areas that see
multiple rounds of storms Wednesday through Friday.

Much of the 00Z guidance indicates a dry Saturday with near
normal temperatures and less humidity. Most models bring another
system into the Plains at some point Sunday into Monday. This
will allow south winds and slightly above normal temperatures to
return Sunday. Odds are that the Quad State will remain dry
Sunday and then see another chance of convection next Monday.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 532 PM CDT Sun Jun 30 2024

High pressure will be pushing drier air throughout the column
for a Visual Flight Rules forecast with little more than FEW-SCT
high level bases. North winds this evening veer slightly to
northeast tmrw as the center of the surface high moves eastward
across the Great Lakes.

&&

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

&&

$$

UPDATE...
DISCUSSION...DRS
AVIATION...JGG