Old Jamestown, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

262
FXUS63 KLSX 131057
AFDLSX

Area Forecast Discussion
National Weather Service St Louis MO
457 AM CST Fri Nov 13 2026

.KEY MESSAGES...

- A cold high pressure system will bring dry weather and below
  normal temperatures to the region through the weekend into
  early next week. Temperatures will slowly climb back to around
  seasonal normals by the middle of next week.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 327 AM CST Fri Nov 13 2026

A high amplitude blocky pattern is setting up across the CONUS with
a deep long wave trough over the eastern U.S., a ridge over the
Plains, and another trough west of that.  The eastern trough is
dragging a high pressure system southward from Canada into the
Mississippi Valley with what looks like the coldest temperatures so
far this season.  Upstream temperatures across Iowa and southern
Minnesota topped out in the upper 30s to mid 40s Thursday afternoon,
and this air is moving into the Mid Mississippi Valley today.
Guidance is giving us highs in the mid 40s today, and this looks
reasonable given the upstream temperatures, accounting for a bit of
airmass modification and somewhat stronger insolation with less
cloud cover today.

Winds will diminish tonight as the high continues building into the
Midwest, and the latest model guidance shows a mostly clear to clear
sky.  The light winds and lack of cloud cover will be ideal for
radiational cooling which will allow temperatures to drop into the
low to mid 20s across most of the area.  Wouldn`t be surprised to
see upper teens in some of our cold spots like Rosebud MO.  Temps
rebound into the 40s again Saturday afternoon under full sunshine
and light winds with the ridge axis overhead.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 327 AM CST Fri Nov 13 2026

The upper pattern translates slowly east Sunday into next week with
the upper level ridge moving across the Midwest into the Great Lakes
Region by midweek.  Meanwhile, the surface high drifts southeast
into the Ohio Valley by Monday, and then continues into the Mid
Atlantic Region by Wednesday and Thursday.  Temperatures across the
Mid Mississippi Valley will slowly warm back to near seasonal
normals in the mid 50s by Tuesday/Wednesday according to the NBM.
This is backed up by the LREF, which is showing very similar
temperatures through the period.  The interquartile range of
temperatures in the ensembles is also very tight through midweek, 2-
3 degrees through Tuesday, and only 3-5 degrees on Wednesday and
Thursday. This lends a high degree of confidence to the forecast
through the period.  There won`t be any chance for precip under the
influence of the surface high and upper level ridge through
Wednesday.  However, global deterministic guidance shows a short
wave trough moving through the Great Plains late Wednesday and into
the upper Midwest on Thursday.  The low level reflection of the
trough pushes another cold front into the Midwest with some modest
low level moisture return ahead of it.  The NBM paints 20-30 PoPs
over much of the area Thursday, and around 30% of the LREF members
have precip for our area as well, so the NBM`s PoPs seem reasonable.

&&

.AVIATION /06Z TAFS THROUGH 12Z SATURDAY/...
Issued at 454 AM CST Fri Nov 13 2026

VFR flight conditions and north-northwest flow are expected to
prevail through the period. Ceilings should scatter out later
this morning into early this afternoon, and a mostly clear sky
is expected thereafter. Winds will diminish this evening and
become light and variable by Saturday morning.

&&

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

&&

$$

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