612
FXUS63 KLSX 300350
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1050 PM CDT Sun Sep 29 2024

.KEY MESSAGES...

- Dry weather is expected for the work week.

- Roller coaster temperatures through the week. Expect above normal
temperatures Monday, with cooler temperatures Tuesday and Wednesday.
Then the remainder of the week will warm back up above normal.


&&

.SHORT TERM... (Through Tuesday)
Issued at 152 PM CDT Sun Sep 29 2024

The upper level low/remnants of TC Helene over eastern KY will
continue to weaken and shift eastward tonight. In the meantime,
moisture continues to advect into the region from the northeast with
isolated showers popping up from time to time over portions of
southern Illinois and southeastern Missouri. This activity will
diminish this evening with loss of daytime heating.

Otherwise, with weak ridging overhead winds will become light and
variable with mostly clear skies, especially over portions of
central and northeast Missouri tonight. Latest forecast soundings
indicate that patchy fog will develop over this area late tonight,
so kept mention in the grids for this time period. Further to the
east, stratus will develop once again and advect in from the east.
This will prevent any fog development over east central/southeast
Missouri and southwest/south central Illinois.

Gradual clearing on Monday with above normal temperatures in the
upper 70s to low 80s. In the meantime, as an upper level trough
slides east along the U.S./Canadian border, it will drag a cold
front into the region late Monday night. No precipitation is
expected with this boundary as moisture will be quite limited and
main energy will be well north of the forecast area. The front will
weaken and exit the forecast area by Tuesday afternoon. Colder air
will begin to filter in with highs only in the upper 60s to upper
70s on Tuesday.

Byrd
&&

.LONG TERM...  (Tuesday Night through Next Sunday)
Issued at 152 PM CDT Sun Sep 29 2024

Surface ridge will continue to build over the region Tuesday night,
eventually shifting southeast of the area by late in the day
Wednesday. So the cooler conditions will be rather brief, then as
south to southwest flow returns to the region once again,
temperatures will be above normal by Thursday. The latest
deterministic as well as ensembles continue to indicate another cold
front will move through the region by late in the work week and into
next weekend. However, the latest LREF cluster analysis indicate
that there is a lot of variation with the strength, timing and
location of the next system as it moves along the U.S./Canadian
border. At this time it should be a dry frontal passage with
temperatures a bit cooler next weekend.

Byrd

&&

.AVIATION...  (For the 06z TAFs through 06z Monday Night)
Issued at 1050 PM CDT Sun Sep 29 2024

Clear skies over central Missouri through northeast Missouri in
combination with light winds will favor the development of fog at
KJEF and KCOU overnight. Expect fog to cause MVFR visibilities with
a potential for periods of IFR visibilities at KJEF. Fog is also
possible at KSUS. Fog will dissipate shortly after sunrise.

Cloud cover over eastern Missouri and southern illinois will persist
through the overnight hours and ceilings are expected to lower to
MVFR status at KSTL, KSUS, and KCPS early Monday morning. Ceilings
should lift to VFR by mid-morning. Otherwise, surface high pressure
over the region will winds light through the TAF period.

MMG/Glass

&&

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

$$

WFO LSX