919
FXUS63 KPAH 082011
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
311 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 /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1238 PM CDT Sat Jun 8 2024

Lingering showers from this morning are now diminishing as a bit
of a lull is anticipated before a complex of thunderstorms
develops tonight. There is some uncertainty with timing, but
KCGI has the greatest risk of seeing TSRA around 04-06z as
model guidance has shifted a bit south. Brief MVFR vsbys are
also possible with heavier downpours. KPAH is more likely to see
SHRA with isolated TSRA not ruled out. Additional SHRA is
anticipated through Sunday morning; however, KMVN/KEVV/KOWB are
now only likely to see -SHRA if anything with the bulk of pcpn
now focused to the south.

The other concern will be for MVFR cigs across most terminals
after 06-09z with IFR cigs also possible at KCGI where the
column will be more saturated. A return to VFR conditions is
progged across all northern terminals by 14-16z as a front
slowly sags south while the low cigs likely remain in place across
the rest of the region.

Southerly winds between 5-10 kts turn light & variable tonight.
Westerly winds shift northerly between 5-10 kts Sunday morning
as a front moves through.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...Flood Watch from 7 PM CDT this evening through Sunday
     afternoon for MOZ086-087-100-107>112-114.
IN...None.
KY...None.

&&

$$

DISCUSSION...DW
AVIATION...DW