Old Jamestown, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

361
FXUS63 KLSX 200005
AFDLSX

Area Forecast Discussion
National Weather Service St Louis MO
705 PM CDT Mon Oct 19 2026

.KEY MESSAGES...

- Above normal temperatures and dry weather will continue
  through the end of the week.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 244 PM CDT Mon Oct 19 2026

A relatively stagnant/blocky pattern will remain over the CONUS
this week with troughs over either coast and an upper ridge
between them. High pressure at the surface over much of the
eastern half of the CONUS completes the Fall pattern which will
keep the Mid Mississippi Valley dry with above normal
temperatures for the next several days. Persistence will rule
the forecast with the blocky pattern in place with temperatures
generally rising a degree or two on Tuesday and Wednesday,
mainly due to airmass modification. Overnight lows Tuesday and
Wednesday will dip into the 40s, which is a few degrees warmer
than this morning`s lows due to airmass modification.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 244 PM CDT Mon Oct 19 2026

The dry blocky pattern remains in place through the end of the week
with temperatures continuing to warm a degree or two each day.  The
upper ridge shifts east late in the week into the weekend which
brings the western long wave trough across the Rockies into the
Great Plains Saturday/Saturday night.  The GFS pushes a cold front
into the Midwest on Sunday, and generates some light rain across
northern Missouri into central Illinois.  The EC is slower with this
progression of the upper pattern and therefore with the cold front
as well.  The LREF mean appears to favor the slower and warmer
solution, with temperatures not really beginning to fall until
Monday.  However the cluster analysis shows a great deal of
uncertainty in both the speed and amplitude of the trough moving
through the Midwest.  Max T IQRs widen from 2-4 degrees in most
locations through Sunday, to as much as 15 degrees on Monday.  The
NBM does cool temperatures off a few degrees on Monday, although it
does not introduce any PoPs on this run.  Think this is a reasonable
start to what should be an inevitable cool down, although confidence
is low in the ultimate timing for this update.

&&

.AVIATION /00Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 702 PM CDT Mon Oct 19 2026

Light winds continue underneath a deck of high level cloudiness.
VFR conditions will continue for at least another few days. The
only potential exception will be if valley fog can develop
overnight. This has occurred the past couple of nights, and with
slightly greater moisture around today this would be a
possibility again tonight. However, high level cloudiness will
play a role in whether we can cool strongly enough to produce
valley fog. Clouds combined with a warmer start to the evening
than yesterday give us lower confidence in valley fog tonight,
so we have stepped back a bit on including this in the TAF for
now. However, if cloud cover trends downward over the next few
hours then this assessment may quickly change.

&&

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

&&

$$

SHORT TERM...Carney
LONG TERM...Carney
AVIATION...Kimble