St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

821
FXUS63 KEAX 291759
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
1259 PM CDT Tue Sep 29 2026

.KEY MESSAGES...

- Several rounds of showers and storms are expected (>95% chance
  for accumulating rainfall) across the forecast area today
  through Thursday night. Heavy rainfall and flooding will be
  possible.

&&

.DISCUSSION...
Issued at 243 AM CDT Tue Sep 29 2026

The main concern this forecast period will revolve around the
potential for several rounds of rain today through Thursday night
possibly leading to flooding. Today, an upper level ridge that has
built over the region will flatten out as a upper level shortwave
moves through the northern Plains into the Upper Midwest. At the
surface, a warm front will lift northward from the Red River Valley
into southeastern Kansas. While the surface feature will remain
south of the area a weak LLJ will over run the front and nose into
the area today bringing the chance (30-50%) of showers and isolated
thunderstorms to the western CWA. Highs today will range from the
upper 70s to mid 80s. Tonight, rain changes will increase across the
forecast area as the LLJ intensifies and becomes more focused over
the area. Best chances will be across the northwestern CWA where
PoPs will be in the 70-90+% range whereas precipitation  chances
south of Highway 50 are less than 15%. PWATs across the northern CWA
will range between 1.80"-2.20" which is around the 100th percentile
for early October. As such, heavy rain will possible, and
consequently a flood watch will go into effect after midnight across
northwest Missouri and extreme northeastern Kansas.

Wednesday into Thursday, a closed upper level trough over the desert
southwest will slowly move out into the Plains. Several lead
shortwave will eject out of the feature bringing the chance for
continued round of storms into the area. A persistent LLJ nosing
into the area will continue to provided added lift and moisture as
PWAT will remain between 1.80"-2.20" during this period. Late
Thursday into Thursday night the closed upper trough over the
central Plains will become an open wave and finally becomes more
progressive. The upper level trough will move through the area
Thursday night pushing a cold front through the area bringing one
last round of heavy rain to the area. All told, current forecast
precipitation amounts for this three day event range from 2-4+
inches for areas along and north of the Highway 36 corridor with 1-3
inches south. Antecedent conditions across northern Missouri after
this past weekend weather are wetter with 1-3" having had fallen and
with the heavier precipitation expected to be focused there the
flood watch that is out through Thursday night appears warranted.
Not as much precipitation fell further south over the weekend and
with lesser amounts forecast we will hold off on expanding the watch
although it may be necessary with further updates. Highs Wednesday
will be in the mid 70s to mid 80s with unsettled conditions keeping
highs in the upper 60s to upper 70s Thursday.

Conditions are expected to be mainly dry in the extended period
although a few left over showers will be possible across the
southern CWA on Friday. Much cooler conditions are expected Friday
as well with highs in the mid 60s to lower 70s. Surface high
pressure then looks to build into the area for the weekend into
early next week. This will aid in keeping highs in the mid 60s to
mid 70s.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1243 PM CDT Tue Sep 29 2026

VFR conditions are expected to remain throughout the evening
Tuesday. Overcast conditions are expected to begin in the early
to mid-afternoon hours, and chances for rainfall will increase,
especially after the 22z-23z timeframe. Rain is expected to be
persistent throughout the night, and are expected to be more
hit-or-miss in the morning. Expected rainfall will potentially
cause reduced visibility, which may lead to MVFR conditions at
times throughout the night. There is confidence that the STJ
area will have the longest duration of rainfall and reduced
visibility. Winds will consistently come out of the south at
5-10kts throughout the TAF period.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...Flood Watch from late tonight through late Thursday night for
     MOZ001>005-011-012.
KS...Flood Watch from late tonight through late Thursday night for
     KSZ102.

&&

$$

DISCUSSION...73
AVIATION...Bjork