St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

293
FXUS63 KEAX 231134
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
634 AM CDT Sun Aug 23 2026

.KEY MESSAGES...

- Cooler and slightly less humid today.

- Showers and thunderstorms possible to likely late tonight into
  Monday morning. Locally moderate to heavy rainfall may be
  possible.

- Warmer temperatures (but seasonal) expected to return Tuesday
  and continue through the remainder of the week.

&&

.DISCUSSION...
Issued at 329 AM CDT Sun Aug 23 2026

Northwesterly flow aloft remains entrenched over the region
between high amplitude ridging across the Rockies and western
CONUS and troughing across the Great Lakes and into Appalachia.
At the surface, high pressure remains in place over the region,
yielding nearly calm winds with some high clouds streaming north
to south overhead. All in all a very pleasant late August day is
expected today, with afternoon high temperatures only forecast
to reach the lower 80s for most locations. More importantly,
good mixing into a dry airmass should allow for dew points to
drop to the upper 50s to lower 60s this afternoon, making for
quite comfortable humidity levels. Quite a bit of mid to high
level cloud cover is likely to move in by late this morning,
with some isolated elevated showers possible by this afternoon
across eastern KS into far western MO. However, with relatively
dry low levels, quite a bit of evaporation is likely. As we
head into tonight, a shortwave trough is progged to translate
across the Dakotas into Iowa along the northeastern periphery of
the upper ridge. Meanwhile, a southeasterly oriented low level
jet will develop late tonight into early Monday morning. This
will usher in moisture return, with PWATs increasing
significantly from this afternoon into late tonight, primarily
across eastern KS into western MO. These features should also
help generate showers and thunderstorms across the region late
tonight into Monday morning, however, CAMs differ considerably
with respect to the exact evolution and intensity of these
showers and storms. The 06z HRRR is the least excited about any
flash flood potential, with total accumulations generally less
than half an inch. However, the 06z NAM Nest suggests the
potential for pockets of 1-2 (and perhaps more) inches, although
the NAM Nest PWATs are significantly higher than other models
and seem a bit unrealistic. The 06z RRFS is somewhere between
the HRRR and the NAM Nest. All that to say that there does seem
to be at least some low end potential for locally moderate to
heavy rainfall late tonight into Monday morning, and WPC has
maintained the marginal risk for excessive rainfall across
eastern KS into far western MO. Convection should dissipate/exit
south of the CWA by late Monday morning, with dry conditions
expected for the remainder of the day and afternoon high
temperatures ranging from the lower 80s across northern MO to
the mid 80s elsewhere.

As we head into Tuesday and the rest of the week, the western
ridge should remain in place, with northwesterly flow aloft
continuing over the CWA as troughing remains over Ontario/Quebec
and into the NE CONUS. This will result in afternoon highs in
the mid to upper 80s through the week and occasional low end
(20 to 30%) chances for showers/storms as disturbances and vort
maxes translate through the northwesterly flow on the
northeastern periphery of the mid/upper ridge.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 627 AM CDT Sun Aug 23 2026

Currently VFR at all terminals under some passing high level
clouds with light and variable winds. High level clouds will
increase in coverage by a bit later this morning, but VFR
conditions are expected through the period. Isolated to
scattered showers and perhaps some thunderstorms may develop
overnight tonight into early Monday morning, so have introduced
a PROB30 for -SHRA to handle this. Winds should remain light (6
knots or less) and variable through the period.

&&

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

&&

$$

DISCUSSION...BMW
AVIATION...BMW