Old Jamestown, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

172
FXUS63 KLSX 301919
AFDLSX

Area Forecast Discussion
National Weather Service St Louis MO
219 PM CDT Fri Oct 30 2026

.KEY MESSAGES...

- Light showers are expected Saturday night through Sunday
  morning with mainly dry conditions this weekend otherwise.

- The next opportunity for widespread, beneficial rainfall will
  be in the Monday night-through-Wednesday morning timeframe.

- Above average temperatures will persist through at least early
  next week.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 217 PM CDT Fri Oct 30 2026

A warm front is currently draped along the I-70 corridor and is
expected to slowly advance northward into northeastern MO and west-
central IL tonight. Scattered showers will continue to lift
northward ahead of the front, but conditions overall will remain
largely dry through tonight.

The first in a pair of upper-level shortwave troughs will pass over
the CWA Saturday morning into afternoon providing at least
widespread clouds. Mainly dry conditions are anticipated to continue
on Saturday as saturation and forcing will be concentrated in the
mid-levels above a layer of easterly flow feeding dry air into the
area, making it difficult for more than sprinkles or a brief shower
to reach the surface. The second shortwave trough will arrive
sometime overnight Saturday night into Sunday morning, which 40 to
70 percent of HREF membership has producing light (measurable)
showers in that timeframe as low-level flow begins to more favorably
veer to southeasterly increasing moisture advection. The greatest
coverage and "heaviest" showers will be across southeastern
MO/southwestern IL where there are even 30 to 50 percent
probabilities of 0.25"+ in global ensemble model guidance. Forecast
soundings suggest that low-level clouds and patchy drizzle could
linger beyond the main round of showers in the morning. Persistent
cloud cover will limit the diurnal range of temperatures this
weekend, although still remaining above average with high
temperatures in the upper 60s to low-70s F on Saturday and then 60s
F on Sunday with thicker cloud cover and precipitation.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 217 PM CDT Fri Oct 30 2026

A potent upper-level trough will slowly propagate eastward across
the central CONUS Monday through Wednesday. Although there are
lingering differences across model guidance on the exact structure
and speed of the trough, there are still projections of anomalous,
deep meridional flow with anomalous PW around the 99th
climatological percentile and a slow-moving front all aligning to
provide an opportunity for widespread, beneficial rainfall across
the CWA. NBM probabilities of 1"+ of rainfall have been consistently
around 50 to 80 percent, highest in central and northeastern MO.
Ensemble model membership generally agrees on most of this rain
falling in the Monday evening-through-Wednesday morning timeframe.
The only impact from this system may just be beneficial rainfall
with present indications that instability will be limited enough to
preclude a clear heavy rainfall or severe weather threat with poor
mid-level lapse rates from widespread clouds and precipitation along
with occlusion tending to "pinch off" the unstable warm sector.
Still, strong deep-layer wind shear will likely be present, leaving
instability trends worth monitoring going forward. NBM interquartile
temperature ranges expand to around 10 F by next Thursday, spanning
between continued above average temperatures and cooler temperatures
near average. This spread is attributed to uncertainties in the
characteristics of the post-frontal airmass including the structure
of the trough impacting the airmass` origin.

&&

.AVIATION /12Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1152 AM CDT Fri Oct 30 2026

Predominantly dry and VFR flight conditions will persist through the
TAF period. Isolated showers are expected in northeastern MO/west-
central IL through early afternoon and then sprinkles or light
showers areawide on Saturday, but impacts are unlikely. Light,
mainly easterly winds will continue.

&&

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

&&

$$

SHORT TERM...Pfahler
LONG TERM...Pfahler
AVIATION...Pfahler