Old Jamestown, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

161
FXUS63 KLSX 292328
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
628 PM CDT Wed Apr 29 2026

.UPDATE...
Issued at 626 PM CDT Wed Apr 29 2026

We made a few minor adjustments to temperatures this evening.
Afternoon temperatures were running a few degrees cooler than
expected, and dewpoints had fallen into the mid 30s across
northern parts of the forecast area. With afternoon cumulus going
away tonight and high pressure bringing calm winds, we expect
pretty good radiational cooling across northern parts of the area
tonight. Thus temperatures will fall close to those afternoon
dewpoint levels. That should for the most part be above the point
where frost occurs, but a few areas of patchy frost can`t be ruled
out across northern MO into west central IL.

Kimble

&&

.KEY MESSAGES...

-Rain chances have increased into the 20-50% range late Thursday
 into Thursday night over parts of the area as a cold font moves
 through.

-Temperatures will continue to be below normal through Saturday
 before a warming trend starts on Sunday.


&&

.SHORT TERM...  (Through Late Thursday Night)
Issued at 223 PM CDT Wed Apr 29 2026

The latest surface analysis is showing a surface high centered over
the central Plains with yesterday`s cold front well off to our south
and east and a stationary front extending from western Wisconsin
into the Dakotas. The northwesterly winds were bringing in cooler
air keeping temperatures in the 50s and 60s early this afternoon.
The HREF is showing the surface highs moving across the area
tonight causing the winds to turn light and variable, but with the
high clouds streaming over us, this should keep lows in the upper
30s and lower 40s except in the urban core of the metro where
lows will likely stay in the mid 40s. As we go into Thursday, both
the GFS/NAM are showing a shortwave trough rotating southeast
around the upper low over the Hudson Bay. As it does it will bring
down the cold front by late tomorrow afternoon into Thursday
evening. There is slightly more QPF on the latest runs of the
GFS/NAM given the lift caused by the both the trough and the
surface front. This goes along with the increase in the NBM`s
PoPS, though the overall rainfall along and north of I-70 is
expected to stay below a tenth of an inch.

Temperatures are still expected to stay below normal with highs on
Thursday in the 60s and lows on Thursday night ranging from the mid
30s over northeast Missouri to the mid 40s from the St. Louis metro
and points to the east and south.

Britt

&&

.LONG TERM...  (Friday through Next Wednesday)
Issued at 223 PM CDT Wed Apr 29 2026

Mainly dry weather is expected Friday into Saturday night as model
consensus is showing a large surface high moving across Missouri and
Illinois and the LREF is only showing <10% of its members
producing any rainfall during this timeframe. There is agreement
between the global models that an additional trough and an attendant
front may move into the Midwest by late in the weekend with the
LREF showing the pattern becoming quasi-zonal over the area next
week. This is when LREF is showing more of its members producing
precipitation over the area each day, particularly on Sunday night
and Tuesday night.

The unseasonably cool temperatures will continue though late week
with highs in the 60s on Friday and Saturday and lows dipping down
into the upper 30s and 40s Thursday night through Saturday night.
The coolest morning still looks to be on Saturday when there will be
the greatest radiational cooling, with some lows dropping down into
the 35-37 degree range over parts of northeast Missouri/west central
Illinois and also in sheltered areas of the eastern Ozarks.  I can`t
rule out the potential for isolated late season frost in these
regions. Otherwise, should see a warm up by Sunday as the high moves
off the east and southwesterly flow sets up allowing highs to
climb back into the 70s by next week.

Britt

&&

.AVIATION...  (For the 00z TAFs through 00z Thursday Evening)
Issued at 626 PM CDT Wed Apr 29 2026

VFR conditions are expected tonight and tomorrow. Winds go light
tonight and turn southwesterly to westerly tomorrow. Some
afternoon cumulus is possible again, but conditions remain VFR.

Kimble

&&

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

$$

WFO LSX