St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

811
FXUS63 KEAX 202323
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
623 PM CDT Sun Sep 20 2026

.KEY MESSAGES...

- Drizzle to light rain / showers possible through tonight. Additional
  light rain possible N/NE Monday

- Much cooler, fall-like, temperatures settle in for the work
  week.

  - Highs 60s/70s, lows upper 40s to 50s

&&

.DISCUSSION...
Issued at 142 PM CDT Sun Sep 20 2026

Precipitation activity largely wound down by mid-morning, leaving
the area predominantly blanketed in broken to overcast skies near
and north of the cold front and more sunshine ahead / south of the
front. Do not expect much, if any, additional precipitation activity
through the early-mid afternoon for much of the area for a few
reasons... noted capping ahead of the front and limited remaining
time (before frontal passage) to mix it out, shallow frontal passage
yielding sizable inversion post-frontal, and limited synoptic scale
support (even weak subsidence) to produce any elevated activity.
Have noted some brief and transient drizzle may be possible with hi-
res sounding suggesting up to 1.5km stratus depth as stratus
continues to drop in from the north. Generally much ado about
nothing. Otherwise, the cooler temperatures are likely the main
story line for most, and more on that in a minute.

There remains a chance for a few renewed convective showers and
thunderstorms late afternoon into the evening, but with the main
cold front now south of the area and approaching the I-44 corridor,
the chances are waning quickly, locally. The HRRR has been adamant
of this southern solution since yesterday among its extended runs,
while synoptic solutions have tended to be further north. Other CAM
guidance, has tended to favor south as well, such as majority of the
12z HREF members. Have trended PoPs drier than NBM thusly.
Regardless, in the unlikely event a storm clips the southern CWA,
the primary risk would be for lightning.

Looking bigger picture, the pattern is a bit messy and yields some
lingering light precipitation chances through Monday. This as a
weak/unorganized low-level/850mb low lifts NE across the area
tonight and a mid-level/500mb open wave to weakly closed low drifts
eastward across Nebraska/Iowa. Neither will produce anything of
significance, but will linger at least lower-end (<35-40 percent)
PoPs over N to NE Missouri through Monday. Then by Tuesday and
through the middle of the week deterministic guidance suggests a
messy attempt at a Rex Block over the Great Lakes region. Late week
sees ridging move back into the central CONUS, but may be hindered
by the evolution of the aforementioned attempted Rex Block. At the
surface, all of this too tends to linger a sizable surface high
around the Great Lakes. This is notable as said surface high is the
source of current cold frontal passage and air mass. So, the main
takeaway/result from all of this for the work week ahead is much
welcome cooler, fall-like, temperatures. Expect highs in the 60s to
70s and lows predominantly in the 50s. Precipitation chances do try
to move back in late work week, but will be dependent on how just
how blocked up the eastern CONUS pattern will be.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 624 PM CDT Sun Sep 20 2026

There is currently a mix of low MVFR to VFR ceilings across the
area, with the lower ceilings situated mainly across northern KS
and MO. This area of lower ceilings will spread southward this
evening and overnight with all terminals expected to fall to IFR
between 03Z (northern sites) and 07Z (southern sites). Early
tomorrow morning, lower visibility will also occur as ceilings
drop into the 200 to 400 ft range. Conditions improve, generally
from south to north tomorrow however, northern MO will likely
remain with IFR ceilings. Winds will be light from the north
throughout the forecast.


&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...None.
KS...None.

&&

$$

DISCUSSION...Curtis
AVIATION...CDB