525
FXUS63 KLSX 231130
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
530 AM CST Mon Dec 23 2024

.KEY MESSAGES...

- Several rounds of rain are expected during the holiday week, with
the best chances (50-80%) Tuesday afternoon through evening, then
tapering off by midday on Christmas.

- Above normal temperatures are forecast for the entirety of the
holiday week, with the warmest temperatures forecast on Friday and
Saturday with highs well into the 50s each afternoon.


&&

.SHORT TERM... (Through Tonight)
Issued at 311 AM CST Mon Dec 23 2024

As the surface ridge continues to slide off to the east today,
the cold front associated with the next system will begin to move
into northwestern Missouri this morning. As it slowly sinks across
the region it will gradually wash out with little to no
convergence along it. In the meantime, weak low level moisture is
advecting northeastward ahead of the cold front with a stratus
deck spreading across the area per latest satellite loop. Also,
the latest forecast soundings continue to indicate dry air below
this cloud base, but enough lift to generate some light
rain/sprinkles beginning this morning. The latest CAMs concur with
this as well with some weak echoes across parts of the area
(mainly along and south of I-70) beneath this subtle, weak
forcing. Despite the increasing cloud cover, the south to
southwest winds will allow temperatures to warm up into the mid
40s to low 50s, especially west of the MS river, with the warmest
temperatures over central MO.

With the front weakening and stalling out across southern portions
of the forecast area tonight, light rain will persist with best
chances across portions of southeast Missouri. CAA will be fairly
weak behind this boundary with temperatures in the upper 20s to mid
30s north of I-70, while the south half of CWA will remain rather
mild with lows only in the upper 30s to low 40s, closer to daytime
highs this time of year.

Byrd
&&

.LONG TERM... (Tuesday through Sunday)
Issued at 311 AM CST Mon Dec 23 2024

On Tuesday, the next in a series of shortwaves will slide east along
the stalled boundary. So increasing chances of rain by Tuesday
afternoon/evening as the strongest mid/upper level forcing moves
through.

Still some differences among the latest LREF ensemble members,
especially on how far north the rain shield will be and when the
rain exits the region. For now the best chances of rain will be
along and south of I-70 with the rain tapering off during the day on
Christmas. Then a bit of break Wednesday night through Thursday.

In the meantime, the next system that will be over the Four Corners
region on Christmas Day, will begin to lift out towards the region.
Latest cluster analysis still indicating strength, location and
timing differences with the shortwave as it approaches the area by
Friday. For now kept with the latest NBM solution, which has the
best chances for rain late Thursday night through Friday morning.

Beyond that, active pattern persists will additional rounds of rain
through next weekend.

As for temperatures through the week, will remain rather mild
through Christmas, then as winds pickup from the south to southwest
ahead of the next system, temperatures will top out in the 50s
Friday through Sunday. Could even see some locations topping out
near 60 degrees.

Byrd
&&

.AVIATION...  (For the 12z TAFs through 12z Tuesday Morning)
Issued at 530 AM CST Mon Dec 23 2024

VFR stratus deck has spread northward across the forecast area
early this morning. Could see brief periods of MVFR ceilings,
especially at KUIN this morning. Otherwise, most TAF sites will
have south to southwest winds up to 15kts at times, while KUIN
could see gusts up to 20kts at times before winds become light and
variable across the region early this evening.

By later this evening, with increasing low level moisture and
light winds, will see patchy fog develop, so could see
MVFR visibilities at all locations after 04z-08z Tuesday. As for
any rain chances, best chances are beyond the forecast period.

Byrd
&&

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

$$
WFO LSX