Old Jamestown, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

969
FXUS63 KLSX 121725
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1125 AM CST Thu Feb 12 2026

.KEY MESSAGES...

- There is high confidence that rainfall will impact the region
  over the weekend. However, the wide range in projected mean
  rainfall totals (0.25-1.25" by early Sunday) persists, leaving
  uncertainty in specific amounts.

- Temperatures will begin to warm again late this weekend with
  widespread 60s and even a few 70s (20-25 degrees above normal).



&&

.SHORT TERM...  (Through Late Friday Afternoon)
Issued at 217 AM CST Thu Feb 12 2026

Regional analysis shows surface high pressure in command of the mid-
Mississippi Valley this morning. Surface ridging resides beneath an
upper-level trough extending from New England through the Ohio and
Tennessee Valleys, with a ridge extending northward through the
Plains and southern Rockies.

A weak shortwave will move across the Plains today and traverse the
mid-Mississippi Valley this afternoon. While this system originally
showed promise for light rainfall, the potential has trended toward
zero. The system is moisture-starved and lacks significant ascent,
with forcing focused along a modest warm air advection wing that
makes a weak attempt to shift eastward today into late tonight.

As this process plays out, a few sprinkles are possible from the tri-
state area (MO/IL/IA) southeast through central Illinois. While HREF
guidance shows some light precipitation developing this morning, it
remains northeast of the CWA; probabilities for measurable
precipitation are below 10% between Davenport, Peoria, and
Springfield (IL). A deep dry layer from the surface through 850MB
will likely prevent sensible impacts from rainfall with a simple
increase in cloud cover today. Highs will range from the 40s in
interior sections of Illinois to the mid-50s in central Missouri.
Lows tonight range from the upper 20s to mid-30s.

On Friday, mid-level ridging over the Gulf will pull moisture into
the Plains ahead of an approaching upper level low out of the
southwest CONUS. Temperatures will warm further, reaching the 50s
for much of the area and the low-to-mid 60s in central and southeast
Missouri.


Maples

&&

.LONG TERM...  (Friday Night through Wednesday)
Issued at 217 AM CST Thu Feb 12 2026

Water vapor imagery shows our next system rotating down the
California coast this morning. This system represents our best
chance for rain, though because it is cut off from the main flow,
refining forecast details remains difficult with a less predictable
path than systems embedded within the main flow. Forecast cycles in
recent days have trended south; this flip back to the north started
with the GFS yesterday and becomes more evident with the latest NAM
solution.

As the upper low moves into the central Plains, surface cyclogenesis
is expected near the OK/TX panhandles. The NAM differs from other
guidance by bringing moisture further north and depicting a double-
barreled mid-level low. While long-range deterministic guidance
keeps the system and associated moisture further south, the NAM
suggests a more eastward track. This would push the warm front
further north, bringing 1-1.25 PWATs as far as I-70.
Ensemble guidance suggests widespread rainfall on Saturday, though
the exact timing and amounts require further refinement. Current
consistency points to a mid-to-late Saturday morning start in
central/southeast Missouri, reaching the Mississippi River by noon
and moving into Illinois shortly after. Uncertainty remains high for
the northern portion of the CWA and along the I-44/I-70 corridor,
where a tight QPF gradient is expected. LREF ensembles indicate a
30% probability of 1 or more near I-70, increasing to 60% between
Rolla and Cape Girardeau. That being said, the IQR conveys a one
inch gap between the lower and upper quartiles, which leaves
adjustment likely through the next 48 hours. Medium range guidance
can use glean in on some of the trends as the system becomes better
sampled as it fully comes ashore through the day today.

Temperatures will be influenced by overcast skies and rainfall.
Where rain is persistent, temperatures will likely stagnate if not
fall slightly. Warm air advection should somewhat help offset some
of the effects. Highs in the mid-to-upper 40s are plausible, with
low 50s possible depending on the onset and intensity of the rain.

Conditions will improve Sunday afternoon as an upper ridge builds
across the Plains. While specific details become less certain mid-
week as NBM IQR spreads increase, the overall trend points to warmer
temperatures from Sunday through Wednesday. We may see widespread
60s and some 70s for several days, with minimal rainfall expected as
the active northern stream steers activity across the northern CONUS.


Maples

&&

.AVIATION...  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1122 AM CST Thu Feb 12 2026

VFR conditions are expected throughout the 18Z TAF period. Light
southeast winds will persist, with some occasional stronger gusts
likely from early to mid afternoon today. Mid and high level cloud
cover will also linger much of the day today, but coverage should
gradually diminish overnight and tomorrow morning.

BRC

&&

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

$$

WFO LSX