108
FXUS63 KLSX 152039
AFDLSX

Area Forecast Discussion
National Weather Service Saint Louis MO
339 PM CDT Sun Sep 15 2024

.KEY MESSAGES...

- Scattered showers and thunderstorms will continue intermittently
  through Monday afternoon, mainly across the eastern Ozarks into
  east central Missouri and southwest Illinois.

- The remainder of the week is expected to be warm and dry.


&&

.SHORT TERM...  (Through Late Monday Night)
Issued at 335 PM CDT Sun Sep 15 2024

Easterly flow from high pressure centered off the coast of New
England continues to push low level dry air into the Mid-Mississippi
Valley. Meanwhile aloft, the remnant low from TC Francine
continues to weaken and lose identity as a closed circulation. With
that said, it`s still producing clouds and showers over the area.
All deterministic model guidance shows
nearly continuous weak to moderate 850mb moisture convergence
over southern Missouri and Illinois where the drier easterly
flow on the periphery of the ridge meets the more moist
southeast flow around the remnant low, with corresponding light QPF.
CAMs also produce intermittent showers in these areas, and
persistence would also support the idea of continuing isolated to
widely scattered convection until the low finally opens up
and is absorbed into the mean flow late Monday. Temperatures through
the period will be very dependent on clouds and precip, particularly
highs Monday afternoon, though persistence should be an excellent
forecast, but with temperatures a bit warmer across the eastern
Ozarks Monday afternoon due to fewer clouds and showers than today.

Carney

&&

.LONG TERM...  (Tuesday through Next Sunday)
Issued at 335 PM CDT Sun Sep 15 2024

The remainder of the week at least through Friday looks dry as a
very blocky pattern sets up with closed low pressure systems over
the eastern and western CONUS and a weak ridge in the middle over
the Plains and Midwest.  The surface ridge that was centered off
the New England coast gets stretched back to the west and ends up
back over the Great Lakes and Ohio Valley by mid-late week.  The
combination of low and upper level ridging should effectively
suppress convection.  Medium range deterministic guidance shows
850mb temps stay in the 16-18C range which mixes down to 84-88F for
highs.  This agrees well with NBM highs through the end of the week.
 The pattern shifts slowly eastward Saturday into Sunday which
brings the western long wave trough into the Plains, but the upper
ridge hangs tough over the Midwest until the end of the period.
Even the 75th percentile of the LREF is dry in our area through
Saturday and only show a small amount of precip on Sunday.  Will
keep the slight chance/low chance PoPs the NBM gave us for late
Saturday into Sunday for now, but they may need to be removed in
subsequent forecasts if the rest of the guidance remains dry.

Carney

&&

.AVIATION...  (For the 12z TAFs through 12z Monday Morning)
Issued at 552 AM CDT Sun Sep 15 2024

VFR conditions prevail this morning, outside of some patchy river
valley fog which will dissipate shortly after sunrise. Extensive
high clouds exist this morning, but we expect cumulus development
this afternoon with showers and thunderstorms popping up from mid
to late afternoon before dissipating near sunset. These
thunderstorms are most likely in central Missouri although they
could affect any TAF location. Valley fog is possible again
tonight depending on how extensive cloud cover is overnight.

Kimble

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&

$$

WFO LSX