110
FXUS63 KPAH 170545
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
1245 AM CDT Wed Jul 17 2024

.KEY MESSAGES...

- Scattered thunderstorms are expected this afternoon mainly to
  the south of a Poplar Bluff Missouri to Madisonville Kentucky
  line. A stray strong storm with gusty winds remains possible.

- Another round of showers and thunderstorms is expected to push
  eastward across the Quad State tonight. Heavy rainfall and
  flash flooding will be possible. The Flood Watch will continue
  as is through 7 AM Wednesday.

- A cooler and much less humid air mass will remain over the
  Quad State from Thursday through early next week.

- A small chance of thunderstorms returns Sunday and increases
  through next Tuesday. At this time, severe storms and
  widespread heavy rainfall are not anticipated.

&&

.UPDATE...
Issued at 1245 AM CDT Wed Jul 17 2024

Updated aviation discussion for 06Z TAFs.

UPDATE...Issued at 1125 PM CDT Tue Jul 16 2024

A band of showers and thunderstorms has recently developed over
the past hour in a zone centered from Perry County Missouri
across the Shawnee Hills of southern Illinois into the Pennyrile
region of western Kentucky. Low level convergence feeding into a
boundary slowly drifting southward will continue to support the
development of showers and thunderstorms overnight. With high
precipitable water values on the order of 2 to 2.25 inches,
thunderstorms will be very efficient rain makers, dropping as
much as 2 to 3 inches of rain per hour. And thunderstorms will
be slow moving given relatively weak flow aloft. As a result, we
have expanded the Flash Flood Watch east and south to include
much of southern Illinois, southeast Missouri, and a large part
of western Kentucky. Similar to last night, it`s possible that
some locations may receive as much as 4 to 6 inches of rain by
daybreak, which could lead to considerable flooding in localized
areas.

&&

.DISCUSSION...
Issued at 320 PM CDT Tue Jul 16 2024

The Quad State will be in weak cyclonic flow aloft in the base
of an upper trough over Ontario and the Great Lakes. Two MCVs
will impact the region through tonight. The first is responsible
for ongoing flash flooding in Jefferson and Perry counties in
southern Illinois. It will ride along I-64 through sunset and
force scattered showers and storms over southern portions of the
region, generally south of a Poplar Bluff Missouri to
Madisonville Kentucky line. The shear is weak and instability is
considerably lesser than expected due to the ample cloud cover.
A stray strong to severe storm with gusty winds cannot be ruled
out.

The second MCV is located over southeast Kansas and will ride
eastward across the Quad State later tonight. It will likely
generate an area of showers and thunderstorms with torrential
rainfall as it moves through the region. The exact zone of
heaviest rainfall is hard to call, but in general, still seems
to be across the north. To this point the flooding concern has
been contained within the existing Flood Watch and the 1-2"
additional QPF is mostly within it, so will leave it alone and
let it go to expiration at 7 AM.

The cold front will push southeast through the Quad State
Wednesday. Although clouds could once again hamper heating ahead
of it to some extent, a juicy air mass should remain and allow
for scattered to numerous showers and storms along and ahead of
the front. Shear will once again be limited, and instability may
be as well, so organized severe storms are not expected at this
time. Heavy rainfall will be more isolated and generally
southeast the heavy rainfall expected through tonight, so
flooding concerns will also be limited Wednesday.

For Thursday through the weekend, the Quad State will be under
the influence of a persistent trough aloft and dry high
pressure at the surface. This will keep the area dry and
downright pleasant through at least Saturday. Highs will be in
the lower half of the 80s with low humidity and lows will be
around 60.

Some PoPs return to the forecast Sunday as a short wave trough
settles over the central Plains and the air mass tries in vain
to modify. The PoPs then ramp up to likely levels by next
Tuesday afternoon, as southwest flow aloft increases over the
region. The prospects for rainfall before then are rather slim,
despite the NBM PoPs. Temperatures will remain below normal
through next Tuesday.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1245 AM CDT Wed Jul 17 2024

High atmospheric moisture paired with a low level convergence
zone along a boundary shifting slowly southward will result in
scattered to numerous showers and thunderstorms overnight,
especially across central and southern portions of the forecast
area. This affects mainly the KCGI, KPAH, and KOWB terminals.
MVFR conditions may be temporarily reduced to IFR in and near
thunderstorm activity. A period of MVFR ceilings is possible in
the morning as the precipitation activity becomes more sparse.
Isolated redevelopment is possible through the afternoon, but
confidence isn`t high enough to include in the TAFs at this
point. Light winds tonight will gradually become northwest at 5
to 10 knots by Wednesday afternoon.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Flood Watch until 7 AM CDT this morning for ILZ075-080-081-
     084>094.
MO...Flood Watch until 7 AM CDT this morning for MOZ076-086-087-100-
     107>111.
IN...None.
KY...Flood Watch until 7 AM CDT this morning for KYZ004-005-007-010-
     011-013>016-018>021.

&&

$$

UPDATE...RJP
DISCUSSION...DRS
AVIATION...RJP