Old Jamestown, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

522
FXUS63 KLSX 222350
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
650 PM CDT Sun Mar 22 2026

.KEY MESSAGES...

- After a brief cool down behind today`s front, expect another
  warm up to near record temperatures by Thursday.

- Another front on Thursday brings cooler temperatures this
  weekend with a light freeze possible.


&&

.SHORT TERM...  (Through Late Monday Night)
Issued at 136 PM CDT Sun Mar 22 2026

As of 1PM, a cold front was pushing south through the forecast area,
not quite to the I-70 corridor. Ahead of the front, it`s another
March scorcher with temperatures approaching 90 degrees. That`s
already broken the daily record at St Louis. Behind the front, winds
shift to the north with a modest fall in temperature considering the
time of day. Strong cold advection will lead to these northwest
winds gusting to 30 to 40 mph at times, with the cool down
accelerating as we lose daytime heating this evening. By morning,
most areas will be in the 30s, some 40 to 50 degrees colder than
this afternoon.

We do see instability increasing ahead of the front today, with hot
temperatures near 90 combining with dewpoints near 60 to produce
surface based CAPE of 1500 to 2000. However, strong capping exists
in the warm sector which is expected to prevent surface based storms
from forming on the front in this region. There is some evidence
that the cap weakens this evening in response to cooling/moistening
aloft, and a handful of high resolution guidance does begin to
produce storms on the front just as it`s exiting our far eastern
forecast area around 6PM or so. This represents our best opportunity
for severe weather today, and it remains low confidence. If these
storms form they will be capable of a hail and wind threat. The
greater chance for rain will be behind the front as moist advection
aloft continues for a ways before the frontal depth increases.

Winds decrease tonight and through the day Monday as surface high
pressure slides by to our north. This trajectory of high pressure
favors only a brief cool down as the core of the cold slides east
with the surface high and return flow begins a quick warm up. That
said, Monday will certainly be the coolest day of this air mass, and
some 30+ degrees cooler than today with highs only in the 50s
despite some sun. That`s a few degrees below normal for this time of
year.

Kimble

&&

.LONG TERM...  (Tuesday through Next Sunday)
Issued at 136 PM CDT Sun Mar 22 2026

To our west over the southwestern deserts a strong ridge has brought
record-breaking heat for the past week or more (and periodically
throughout the winter). After the brief cool down behind today`s
front, the ridge will gradually expand its influence eastward again
through the coming week. As surface flow turns southerly and
southwesterly with time, we`ll see temperatures rising back well
above normal values. Wednesday sees the sharpest warm up, back into
the 70s to low 80s, while Thursday is when this round of heat peaks
ahead of the next cold front. We`ll once again be pushing record
high territory in the upper 80s and low 90s. In fact, we could
challenge all time March high temperature records as most locations
to our west have already done in recent days. NBM probability of 90+
on Thursday is on the order of 20 to 60 percent across the forecast
area.

Thursday`s front is associated with a wave emanating out of a larger
low in the Gulf of Alaska. This pushes across the top of the ridge
on Wednesday and then digs southeast through the Plains and Great
Lakes on Thursday. By Thursday moisture will have increased across
the Mississippi Valley in advance of the front, with dewpoints
pushing back to near 60. It sets up a situation quite similar to
today where we see building instability beneath a cap of warm air
aloft. So this will be our next period to watch for the potential
for severe thunderstorms if that cap is able to erode before the
front arrives. However, once again, it looks like the best potential
for synoptically driven precipitation is behind the front Thursday
night into Friday. I do say precipitation because the incoming cold
air has the potential to switch rain to some snowflakes on Friday.

Speaking of that cold air, the source air mass up over Canada is
still quite cold, in fact one of the few land areas globally that is
below normal right now. With potentially record setting warmth ahead
of it, the next incoming cold front once again brings a very sharp
temperature drop. This time the cold side of the front is even
colder. NBM probability of temperatures falling below freezing is
about 40 to 70 percent area wide by Saturday morning.

Kimble

&&

.AVIATION...  (For the 00z TAFs through 00z Monday Evening)
Issued at 638 PM CDT Sun Mar 22 2026

Dry and VFR conditions are forecast at the regional terminals
through the TAF period. A cold front is now south of the TAF
sites, and in its wake strong 20-30kt northerly gusts are
impacting all terminals. These will continue through the evening
and gradually weaken overnight. There remains a small chance for
MVFR CIGs to advect south from Iowa and impact KUIN overnight, but
recent observations suggest that southward advection is stalling
and the lower clouds will stay away from the terminal.

MRB

&&

.CLIMATE...
Issued at 136 PM CDT Sun Mar 22 2026

Record High at STL for 3/22
       STL
3/22 88 (1907)

Record Highs on March 26:
St Louis   87 in 1991
Columbia   86 in 1910
Quincy     82 in 1991

All Time March High Temperature Record:
St Louis   92 on March 24, 1929
Columbia   92 on March 21, 1907
Quincy     88 on March 21, 1907


&&

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

$$

WFO LSX