Old Jamestown, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

869
FXUS63 KLSX 152326
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
526 PM CST Mon Dec 15 2025

.KEY MESSAGES...

- Above normal temperatures are expected through Wednesday night
  ahead of a cold front.

- Rain showers, and possibly a thunderstorm, are expected on
  Thursday with the cold frontal passage. Behind the front, a
  brief return to seasonably cold temperatures is expected.


&&

.SHORT TERM...  (Through Late Tuesday Afternoon)
Issued at 219 PM CST Mon Dec 15 2025

South/southwest winds will lighten up this evening as the surface
pressure gradient, but remain around 5-10 mph overnight. These
winds will help keep temperatures quite a bit warmer than we have
just experienced the past couple of days. Another factor that
could impact temperatures is upstream stratus across
southwest Missouri. This area of stratus so far has not scattered
out or dissipated. If it survives the next couple of hours, it
likely will impact at least portions of the region tonight. Once
the sun sets, another possibility would be for the stratus to
expand overnight (and lower). If this occurs, it may impact much
of the CWA. For now, do believe parts of east central and
southeast Missouri as well as southwest Illinois will have at
least a few hours of this low stratus. That should lead to
slightly warmer overnight lows in these areas. Lows in the mid to
upper 20s are forecast, but I would not be too surprised to see
some locations not get below the freezing mark if the stratus
stays long enough into the night.

Stratus may continue to be a concern into the day on Tuesday, but
there is more uncertainty the further out in time you go. This time
of year it is very difficult for stratus to easily lift/scatter out
as we are within a week of the winter solstice. In areas where
stratus is most likely to linger longest (southeast Missouri into
south-central Illinois), highs only in the mid 40s are forecast.
However, temperatures could be some 5-8 degrees colder than this
forecast if the stratus lingers into the mid afternoon. Further
west, low to mid 50s are expected where more sunshine is forecast.


Gosselin

&&

.LONG TERM...  (Tuesday Night through Next Monday)
Issued at 219 PM CST Mon Dec 15 2025

(Tuesday Night - Wednesday)

Mild and dry conditions are forecast through midweek. Lows Tuesday
night are expected to be in the upper 20s to mid 30s with highs on
Wednesday in the 40s/50s.


(Wednesday Night - Friday)

A strong midlevel shortwave trough is forecast to amplify across the
central Plains late Wednesday night into early Thursday, with a
surface low moving across the Upper Midwest into the Great Lakes. A
cold front is expected to be draped from north to south equatorward
from this surface low, and sweep from west to east across the bi-
state region Thursday morning. Widespread showers are expected with
this frontal passage due to increasing low-level moisture
convergence, diffluence ahead of the approaching trough, and upper-
level jet dynamics. A couple of rumbles of thunder are also
possible. The EPS has probabilities for at least 100 J/kg of MUCAPE
topping out in the 30-50% range Thursday morning across southeast
Missouri and southwest Illinois.

This does not look like a significant widespread rain maker, but at
least some light rain amounts are expected areawide. LREF
probabilities for at least 0.10" of rain range from 40-80% from west
to east, but drop to 10-50% for 0.25" or more of rain.

Behind the front, very strong low-level cold air advection is
expected. Non-diurnal temperatures are forecast, with readings
dropping from the 50s into the 30s by late afternoon/early evening.
That combined with gusty northwest winds, and it should feel at
least 10+ degrees colder than that too. Speaking of the winds, gusts
of 30-40+ are likely Thursday afternoon/evening. Winds at the top of
the mixed layer approach 50 knots on the GFS during this time,
which is an indicator for at least the possibility of advisory level
(45+ mph) gusts. The synoptic pattern also favors very strong
winds/gusts, so this is a period to keep an eye on.

A (brief) return to seasonably cold temperatures is forecast
Thursday night and Friday. Lows Thursday night in the 10s to low 20s
are expected, with highs topping out on Friday in the 30s to low 40s.


(Friday Night - Next Monday)

Mild and dry conditions are forecast for this upcoming weekend as
the mid/upper level flow goes zonal across the CONUS. This allows
for mild Pacific air to flood the continental US with mild
temperatures. There is still a signal for a cold frontal passage
sometime late this weekend, but uncertainty continues as to how far
south the boundary will get and how cold it gets behind the front.
The inter-quartile range on the NBM approaches 15 degrees with
respect to high temperatures on Sunday in many locations,
illustrating this uncertainty quite well.


Gosselin

&&

.AVIATION...  (For the 00z TAFs through 00z Tuesday Evening)
Issued at 526 PM CST Mon Dec 15 2025

A rather small bank of MVFR clouds between 1.5-2.5k feet in
elevation is moving across the Ozarks this evening. There was some
concern that cloud cover might expand in the cooler nighttime
environment and/or track northeast over the metro terminals.
Satellite trends currently show this is not materializing so far
with movement more east than north. Additionally, there is
reinforcement in the mid-level cold air with northerly flow
pushing from Iowa into Missouri/Illinois. This continue to be
watched, but should keep MVFR cloud south of the metro TAF sites.

VFR conditions are expected throughout the period.

Maples

&&

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

$$

WFO LSX