Old Jamestown, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

314
FXUS63 KLSX 151812
AFDLSX

Area Forecast Discussion
National Weather Service St Louis MO
112 PM CDT Thu Oct 15 2026

.KEY MESSAGES...

- A few strong/severe thunderstorms remain possible in southwest
  Illinois from early to mid afternoon, with damaging wind gusts
  and a brief tornado possible. For other areas, the threat of
  severe storms is low.

- A strong cold front will bring blustery northwest winds an a
  sharp cooldown overnight. Below average temperatures are
  expected through Saturday, with morning frost increasingly
  likely Saturday and Sunday mornings.

- A steady warmup is expected Sunday onward.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 106 PM CDT Thu Oct 15 2026

The focus of the short term period continues to be on the potential
for showers and thunderstorms early this afternoon, followed by the
passage of a fall-like cold front this evening and overnight. The
latter will bring blustery northwest winds and a sharp cooldown, and
it will feel a lot more like you`d expect for mid-October (or even
later).

As of early afternoon, a surface low was located across north-
central Missouri, with a warm front extending east-southeastward
into southwest Illinois, and a sharp cold front approaching the
Kansas City metro area. Meanwhile, a pre-frontal trough was also
noted across east-central and southeast Missouri, with locally
enhanced surface convergence along it. This pre-frontal trough has
been the focus for convection through the morning, and as of this
writing weak and largely elevated thunderstorms have moved across
the Mississippi River and into southwest Illinois. Ahead of these
storms and the pre-frontal trough, deeper moisture, slightly
enhanced instability (~1000J/kg MLCAPE), and backed (albeit weak)
surface winds have developed. While cloud cover is still abundant,
there has been at least some clearing, and this environment
appears to be the most favorable area for strengthening storms
over the next few hours. Wind shear is a bit weaker here than
further west, where stronger mid/upper level flow exists, but
there is just enough to support a low-topped supercell and a
brief tornado or two, mostly likely before 3 PM as most of this
activity should move east of the area by then. Overall though,
confidence is not high that storms will become severe until
after they exit the area.

West of the pre-frontal trough, while bulk wind shear is a bit
higher, veered surface winds and meager instability (in spite of
more ample clearing), and a lack of redevelopment in high-resolution
model guidance do not strongly suggest that more storms are likely
upstream any later in the afternoon. While we likely will see some
warm air advection showers, and also a few showers along the
advancing cold front, but the probability of strong or severe storms
in this area is low.

Late this evening, the previously mentioned cold front will surge
through the region, bringing strong cold air advection and blustery
surface winds. While we don`t expect Advisory-level wind speeds,
gusts to 30-35 mph will be well within reason, particularly during
the day tomorrow as mixing increases. Meanwhile, temperatures will
drop quickly, with morning lows dipping into the 40s in most areas
before warming only slightly into the 50s during the day thanks to
the persistent cold air advection. After reaching the 90s just two
days ago, temperatures Friday will be approximately 15 degrees below
average. Brisk winds will persist through the day, and weaken in the
evening and overnight, allowing for efficient cooling and low
temperatures dropping into the low 40s to mid 30s Saturday morning.
A few protected river valleys may even flirt with the freezing mark
as well, especially in northeast Missouri and the Ozarks, and it`s
increasingly likely that these wind-protected areas will see some
frost Saturday morning. In fact, NBM probabilities for minimum
temperatures of 32 degrees or less increase to nearly 50% in
northeast Missouri, and chances are likely similar in Ozark river
valleys where small-scale cool air drainage contribute
additional cooling.

&&

.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
Issued at 106 PM CDT Thu Oct 15 2026

From Saturday onward, a slow, steady warming trend is expected to
develop as an upper level ridge moves overhead, and south-
southwesterly low level flow becomes re-established. Surface high
pressure and a dry-continental airmass should also keep
precipitation chances minimal.

After a very chilly morning Saturday, temperatures are likely to
rebound only into the low 60s, with a slight increase from the day
before thanks largely to clear skies. Overnight, another very chilly
night is expected, as surface winds will remain very light and
radiative cooling is expected to be quite efficient. Current
deterministic forecasts suggest that morning lows in the mid to
upper 30s should be common area-wide, with another opportunity for a
brief freeze in Ozark river valleys in particular thanks to cool-air
drainage. Sunday morning should be the last opportunity for a
freeze, although some patchy frost will be in play again Monday
morning. From Sunday afternoon onward, southerly low level flow
becomes firmly established, and temperatures will steadily warm each
day through mid-week. Temperatures are expected to climb back to
near average by Sunday afternoon, with high confidence (90+%) in
above average temperatures Tuesday onward, and a reasonable chance
to exceed 80 degrees (40-60%) Wednesday onward. Meanwhile, little
additional precipitation is expected for the next week.

&&

.AVIATION /18Z TAFS THROUGH 00Z SATURDAY/...
Issued at 100 PM CDT Thu Oct 15 2026

Thunderstorm chances are decreasing at all local terminals, and
now attention turns to low ceilings and a sharp cold front with
gusty northwest winds. Some improvement to VFR ceilings is
expected for a few hours at all terminals this afternoon with
the possible exception of UIN. However, ceilings are expected to
dip back to MVFR and locally IFR levels along and behind a
passing cold front this evening and overnight. Winds will also
turn to the northwest and increase sharply, and remain elevated
through the end of the period. Ceilings are expected to improve
again briefly tomorrow morning, but MVFR low stratus will
likely return near the end of the period.

BRC

&&

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

&&

$$

SHORT TERM...BRC
LONG TERM...BRC
AVIATION...BRC