St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

628
FXUS63 KEAX 262316
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
616 PM CDT Sat Sep 26 2026

.KEY MESSAGES...

- Showers and occasional general thunderstorm chances continue
  into Sunday morning.

- Increasing confidence in a period of wet conditions from
  Tuesday through at least Friday. Rounds of heavy rain may
  yield an increasing river and areal flooding threat through
  the week.

&&

.DISCUSSION...
Issued at 239 PM CDT Sat Sep 26 2026

Sort of a tale of two days situation across the area so far today
with a couple of waves of showers/weak thunderstorm activity. The
first of which has already all but moved out of the area, and the
second more recently moving into western areas of the CWA. In
between, areas roughly east of US-65 are even enjoying some sunshine
peeking through. All of this activity is broadly associated with a
mid-level shortwave trough lifting NE through the region and smaller
embedded disturbances and will continue to linger periodic scattered
shower and weak thunderstorm activity into Sunday morning before
more substantial drying and mid-level height rises move in. While
initial hi-res guidance suggested relative drying or lesser activity
into this afternoon, showers and weak thunderstorm activity may end
up being more prevalent than initially thought across portions of
far eastern Kansas and into western/northwest Missouri. This due to
MCV-like depictions noted on radar throughout the day as activity
has lifted into/through Kansas. Coupled with the broader lift with
the mid-level wave, tend to suspect an uptick in weak
shower/thundershower activity and have begun to be seen on radar as
of 2pm in NW Missouri. Nothing of significance aside from a rumble
of thunder possible and brief heavy rain. And then overnight, LLJ
noses into the area and should again blossom at least scattered
shower/thundershower activity into the area. Currently, chances
overnight tend to be best south of Highway 36. Previously mentioned
mid-level height rises slide in Sunday, drying conditions out
through the day.

An interesting, likely quite impactful, pattern sets up across CONUS
during the work week. This being current nor`easter milling about, a
western CONUS trough/cutoff low moving in-land, the remnants of
Pacific hurricanes Polo and Odalys lifting northward across Baja
California into the increasingly SW flow pattern, and Gulf moisture
streaming northward through the Plains. At this point in time, there
is high confidence in the broad scale pattern evolution through at
least mid-week, if not the entire work-week. And in effect this
spells out a heavy rain/flooding threat that runs from the
central/southern Intermountain West and into the Southern to Central
Plains. For the immediate area, this potential tends to reside at
Days 4/5 (Tuesday/Wednesday) and beyond. For added confidence in the
potential, GFS/Euro ensembles (as well as their AI versions)
highlight and expansive/broad area of 2-4+ inch QPF through mid-late
week, which is impressive when you consider the washed out nature of
ensemble QPF. The potential is further highlighted by deterministic
solutions, including the 12z GFS, depicting PWats climbing toward
and above 2 inches (highly anomalous this time of the year) and
swaths/pockets 6-8+ inches QPF. But given the time horizon, there is
a good degree of uncertainty in the finer details, such as the exact
track of the mid-level cut-off low, its associated surface low, and
frontal positions so will stress that locations of peak amounts
remain uncertain. After an expansive (geographically) coordination
call with WPC today, broad Slight Risks exist on Days 4/5 for the
WPC Excessive Rainfall Outlook product, with likely upgrades as
finer details come into better focus. Lastly, the current best
potential tends to reside over the NW half of the CWA or so,
especially as you consider those areas have the most saturated soils
as well (via NASA SPoRT).

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 611 PM CDT Sat Sep 26 2026

Light rain showers are working east across the region leading to
drying conditions from west to east; however, additional shower
activity is expected to develop early Sunday morning. MVFR stratus
is expected to develop after 14Z Sunday morning along and north
of I-70 and looks to remain fairly consistent throughout the
day.

&&

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

&&

$$

DISCUSSION...Curtis
AVIATION...BT