781
FXUS63 KPAH 302238
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
538 PM CDT Sun Jun 30 2024

.KEY MESSAGES...

- Less humid and more pleasant conditions are expected the rest
  of today and especially on Monday. Heat and humidity return
  by the middle of the week with heat index values over 100
  degrees Wednesday and Thursday.

- An unsettled pattern with daily chances of showers and storms
  begins on Wednesday and continues through Saturday. There is
  the potential for heavy rainfall and flash flooding. Although
  there is not a strong signal for severe thunderstorms, a few
  severe storms appear possible, particularly on Thursday and
  Friday.

- Afternoon and evening thunderstorms will be a concern for
  outdoor events July 3rd-5th.

&&

.UPDATE...
Issued at 532 PM CDT Sun Jun 30 2024

Updated Aviation discussion for 00Z TAF Issuance.
&&

.DISCUSSION...
Issued at 151 PM CDT Sun Jun 30 2024

Drier air is working into the area behind a "cold" front this
afternoon. Despite a dewpoints in the 70s across parts of the
area it is still quite a bit less humid than yesterday.
Dewpoints in the 50s over central Illinois and eastern Missouri
are aimed at the region and that airmass should keep pumping
into the area through the next 12-24 hours. Monday looks very
pleasant by July standards with highs in the low 80s. South
winds begin to bring increased humidity back on Tuesday but the
full effects of this will likely hold off until Wednesday.

By Wednesday afternoon we will be right back in the thick of it
with afternoon highs well above 90 and dewpoints back into the
middle 70s. A residual capping inversion looks to hold off
convection until the late afternoon Wednesday and afternoon
heat index values look like they may work back into the 105-112
range which is in advisory/warning threshold. Late Wednesday the
right rear exit region of a jet centered over the Great Lakes
helps initiate quite a bit of convection over the area,
although this feature is subtle enough it`d be reasonable to
expect changes. If convection can initiate the ~2.2" PWAT
airmass will produce very efficient rainfall rates. MLCAPE
values ~ 3000 J/kg with about 25 to 30 kts of deep-layer shear
may spring a severe thunderstorm threat as well - mainly in the
form of damaging winds.

A stronger shortwave then approaches Thursday into Friday. This
feature has reasonably good agreement between GFS/ECMWF members
in the 12z guidance suite and aids in keeping thunderstorms
going over the area. The upper level pattern gives us about 48
hours of steady subtle lift through Friday afternoon overtop of
a 2"+ PWAT airmass. Thoughts on this are:

1) It has been very consistent in EC/GFS guidance for several
days but depending on something as subtle as the position of a
jet max means that shifts are still something we should be
expecting.

2) If thunderstorms don`t get going we will be advisory/warning
level again for heat on Thursday and Friday with high 70s
dewpoints.

3) If thunderstorms do get going it will be hard to not have
some degree of flash flooding given the efficiency and
probable persistence of storms.

4) Fireworks displays and other outdoor events need to pay close
attention to the weather and prepare for disruptions as its hard
to picture a scenario where there isn`t at least the threat of
thunder Independence Day evening.

A front then tries to work through for the weekend by the trend
in the 12z guidance is for it to be a little slower to work
through and less effective at sweeping out heat and humidity
when it does. This checks out climatologically so will monitor
to see if it holds.

&&

.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.

&&

$$