307
FXUS63 KPAH 082322
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
622 PM CDT Sat Jun 8 2024

.KEY MESSAGES...

- A front will bring the risk for multiple rounds of showers and
  thunderstorms this evening through Sunday afternoon,
  especially over southeast Missouri and portions of southern
  Illinois and far western Kentucky.

- The risk for severe weather and flash flooding remains the
  greatest in southeast Missouri. Between 8PM to 2AM, storms
  will be capable of causing damaging winds and large hail
  around 1 inch. An isolated brief spin up tornado also cannot
  be ruled out. A Flood Watch remains in effect from this
  evening through Sunday afternoon as 1 to 3 inches of rain,
  with locally higher amounts is expected with additional rounds
  of storms.

- Next week will start off dry with slightly below normal
  temperatures in the upper 70s and lower 80s. A warming trend
  will eventually lead to above normal temperatures by the end
  of the week with high temperatures reaching the low 90s. Rain
  chances remain minimal through most of the week.

&&

.DISCUSSION...
Issued at 311 PM CDT Sat Jun 8 2024

A warm front is now approaching SW Indiana as sfc obs show
winds have veered to the SW with breaks of sun across the rest
of the FA. The increase in diurnal heating will allow for
destabilization, especially in SEMO as an influx of
theta-e/moisture will cause dewpoints to rise into the upper 60s
and lower 70s. This is where model soundings show pockets of
2000-3000 J/kg of MLCAPE, along with about 40 kts of effective
bulk shear setting up this evening. As a mid-level shortwave
approaches, modest ascent will cause scattered thunderstorms to
develop along the aformentioned boundary. Convection then grows
upscale into a MCS as storms push eastward towards the
Mississippi River later tonight.

There is the potential for a few strong to severe storms between
8PM to 2AM, especially in SEMO where SPC has a slight risk in
their D1 convective outlook. The greatest hazard of concern
looks to be damaging winds with bowing segments as DCAPE
initially will be 800-900 J/kg. Large hail around 1 inch is
also possible given 700-500 mb lapse rates between 6.5-7.0 C/km.
While the risk is low, a brief spin up tornado cannot be ruled
out given sfc-1 km shear of 15-20 kts, and STP values around 1.
While a few severe storms are possible, the risk looks to be
confined to mainly SEMO.

As for the flooding potential, recent runs of the CAMs have
shifted the axis of heavy rainfall more south. The 12z HREF PMM
shows a sharp gradient with locally 4 to 5 inches of rain over
Carter/Ripley counties while the rest of southeast Missouri and
portions of southern Illinois and far western Kentucky are
still looking at 1 to 3 inches. Given that the mean cloud layer
flow will be parallel to the frontal boundary orientated east-
west, there is concern for training convection, especially in
the Ozark Foothills that will lead to flooding. In fact, PWATs
in the 99th percentile will max out around 2.00 to 2.25 inches
where the ESATs also show mean specific humidity values above 13
g/kg at 850mb. Combined with thermal profiles showing skinny
CAPE early Sunday morning along with a warm depth cloud layer of
12-13 kft, rain rates will also likely contribute to flooding
problems with multiple rounds of storms through Sunday morning.
For this reason, a Flood Watch remains in effect 7PM this
evening through Sunday afternoon where WPC has a slight risk in
their D1 ERO.

By Sunday afternoon, a cold front will slowly sag more south
allowing for dry conditions to settle over the FA Sunday
evening as high pressure builds over the Ohio Valley. MaxTs will
be much cooler compared to today in the upper 70s and lower
80s. Radiational cooling Sunday night will allow for minTs to
fall into the mid to upper 50s.

The week will also start off cooler and dry as high pressure
remains in control; however, southerly return flow returns on
the backside by the middle of the week. Hotter and more humid
conditions are progged to return with maxTs eventually reaching
the lower 90s by Thursday with minTs in the upper 60s to near
70. While NBM has slight chance PoPs progged Wednesday/Thursday
across portions of the FA, think the better risk for isolated
diurnal convection holds off until next weekend as it will take
some time to overcome the low dewpoints in the 50s through the
first half of the week.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 618 PM CDT Sat Jun 8 2024

A complex of thunderstorms is developing over southwestern MO
and will be moving east this evening and overnight. KCGI is the
most likely to be affected by these storms with KPAH likely
seeing showers but some distant thunder. MVFR and IFR cigs are
expected to move in with these storms and MVFR visbys could be
possible under heavier downpours. VFR conditions are expected to
return by tomorrow afternoon.

Winds will be light and variable overnight for the most part and
then becoming westerly then northerly tomorrow with the passage
of a front.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...Flood Watch through Sunday afternoon for MOZ086-087-100-
     107>112-114.
IN...None.
KY...None.

&&

$$

DISCUSSION...DW
AVIATION...SHAWKEY