985
FXUS63 KLSX 272302
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
602 PM CDT Wed Aug 27 2025

.KEY MESSAGES...

- The forecast has trended drier for central and southeast
  Missouri on Thursday.

- Dry weather and relatively mild temperatures continue in the
  forecast into next week.


&&

.SHORT TERM...  (Through Late Thursday Night)
Issued at 233 PM CDT Wed Aug 27 2025

High pressure over the Ohio Valley will continue drifting east
through Thursday night.  Meanwhile, a shortwave which is moving into
the Northern Plains will move southeast into the Mid Mississippi
Valley on Thursday.  The low level jet increases ahead of the wave
across the southeast Plains producing moderate to strong moisture
convergence near the MO/KS/OK/AR border.  The model trends over the
last 24 hours have been for this area of moisture convergence to
move farther to the southwest bit by bit.  At this point, all
operational deterministic guidance keeps our area dry for the
duration of the short term as this system moves by.  Additionally,
only the 90th percentile and above of the latest ensemble guidance
(HREF/NBM/LREF) shows any precip in our forecast area. Have
therefore removed the remaining mentionable PoPs  on Thursday from
our central and southeast Missouri counties.  Otherwise, little
change in the temperature forecast with the slow warming trend into
the low to mid 80s in most locations, except where thicker cloud
cover will suppress highs across the Ozarks.

Carney- There is a chance (30-50%) of light rain over sections of
  central and southeast Missouri from morning to early afternoon
  Thursday.

- Aside from Thursday`s rain-cooled locations, temperatures will
  warm slightly, but remain roughly 5 degrees below normal through
  this weekend.


&&

.LONG TERM...  (Friday through Next Wednesday)
Issued at 233 PM CDT Wed Aug 27 2025

The long wave upper pattern doesn`t change much for Friday through
next Wednesday.  The ridge over the western half of North America
fractures over Canada on Friday and the closed anticyclone drifts
east along the U.S./Canada border through early next week.  This
briefly attenuates the long wave trough over eastern North America.
As the short wave ridge moves east of Hudson Bay, another short wave
trough digs in behind it and reamplifies the long wave.  The upshot
is the Mid Mississippi Valley remains in northwest flow aloft to a
greater or lesser degree into next week.  This will result in a
continuation of relatively mild temperatures, with highs within a
few degrees of normal for late August/early September.  While the
official forecast remains dry, there are some members of guidance
(most notably the GFS) that kick out some precip in the Sunday-
Tuesday time frame as the aforementioned short wave moves over the
Mississippi Valley.  There`s been run-to-run variability with how
the models handle these features over the past few days, so
confidence in any rain is very low.  Additionally, the majority of
the LREF members (70+ percent) show no precipitation during this
period.  The NBM is also dry until Wednesday when introduces slight
chance PoPs.  This seems reasonable as the amplifying pattern pushes
another cold front into the Midwest which will hopefully bring us
some much needed rain.

Carney

&&

.AVIATION...  (For the 00z TAFs through 00z Thursday Evening)
Issued at 559 PM CDT Wed Aug 27 2025

VFR conditions are expected at all sites through the 00Z TAF
cycle. High level cloud cover and slightly warmer temperatures
should limit fog formation overnight, although it won`t be
completely impossible to see a few patches of fog at SUS if skies
can stay clear and temperatures drop lower than expected. This is
very unlikely, though. Otherwise, light winds can be expected,
with some modest south to southwest breezes tomorrow afternoon.
While rain is expected to the southwest of our local terminals,
no precipitation is expected locally.

BRC

&&

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

$$

WFO LSX