St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

511
FXUS63 KEAX 301941
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
241 PM CDT Wed Sep 30 2026

.KEY MESSAGES...

- Multiple Rounds of Rain Showers & Storms Through Friday

- Isolated Strong to Severe Storms Possible Tonight

- Flooding Expected, Especially Northwest Missouri

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 240 PM CDT Wed Sep 30 2026

Surface cyclone centered over the Panhandle Region continues to
deepen with deep troughing over the Four Corner Regions sending
plenty of dCVA into the southern Plains. From the Central Plains
into the lower Missouri River Valley, low-level flow has been
southerly transporting plenty of moisture, pushing a warm front into
northern Missouri. This warm front in northern Missouri has been the
focus for persistent rain shower activity for much today. So far, it
has mostly been stratiform forced primarily with isentropic upglide.
The surface cyclone will continue to push eastward through the
evening, with surface pressure falls expanding into eastern Kansas
and the far reaches of the northwest Missouri. Expansive cloud cover
has limited insolation today, but CAPE is arriving via strong theta-
e advection, especially with the extra moisture being pumped in from
tropical activity. Overall lapse rates are not overly impressive,
but without the usual EML in place, there is not a notable cap in
place. As convergence increases, we are expecting to see more shower
and storm development over central and eastern Kansas through later
this evening, eventually moving into northeastern Kansas and
northwest Missouri. Deeper updrafts will be achievable in this
airmass given the warm cloud depths and ample moisture through most
of column. Low-level jet development along with increasing mid-level
flow will provide more wind shear later this evening, allowing storm
activity to organize. The main question for our western and
northwestern zones is how long can activity remained organized. A
few strong to severe storms will be possible, capable of damaging
winds and maybe some low-end severe hail (around quarter size in
diameter). With very low LCLs and increasing low-level hodograph
curvature, storms may be capable of producing circulations that
could produce a tornado. Overall, the better environment for this
threat remains over Central Kansas closer to the center of the low
pressure system. Northeast Kansas and northwest Missouri are showing
more cross-wise low-level vorticity, which would make it more
difficult for stronger storms to produce a tornado. The window for
development will likely be narrow, and usually in these environments
if one is produced, will be brief and weak. The damaging wind gusts
are the more prominent threat with activity this evening. Continued
rainfall will also be a problem for flooding, both areal flash
flooding and increasing river/stream levels through the end of the
work week. Areas in northwest and northern Missouri have seen a
couple inches of rainfall already, and northwest Missouri especially
is in line to see another 1-2 to inches of rainfall. Some of the 12z
guidance, including the HRRR, brings heavier rainfall southward
toward the Interstate 70 corridor, including the KC Metro. However,
other model trends have been lighter on precipitation. For now, have
kept the flood watch as is, but if we continue see pockets of 3-4
inches possible southward, a southward expansion may be come
necessary. While northern Missouri and northeastern Kansas can see
flooding issues overnight, areas southward toward the Interstate 70
corridor likely will not see flooding issues until Thursday
afternoon.

Thursday afternoon, the cyclone will start to move east-southeast,
with the stationary front in northern Missouri becoming a cold
front. This is being caused by surface high pressure moving
southeastward out of the northern Plains. Continued lift will
provide rain shower activity for most of the day Thursday and into
the evening hours, with some potential for non-severe thunderstorms,
though true instability will be limited. This is when our central
Missouri and our southern zones in the forecast area will start to
see more efficient rainfall rates. By Friday afternoon, the front
should clear the forecast area with high pressure building in, and
most of the shower activity will exit.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 240 PM CDT Wed Sep 30 2026

For this weekend, we are expecting drier conditions, seasonable
temperatures, and overall, fall-like weather. This will be
contributed by zonal flow progressing across the northern CONUS,
surface high pressure systems to our north, and the development
of a 500mb high pressure system in the desert southwest. For
Saturday, a surface high pressure will be over the Great Lakes,
and will continue to progress eastward. We will still see its
influence with temperatures in the upper-60s to low-70s, cooler
overnight temperatures, and a southeasterly wind. On Sunday, a
500mb high pressure center will further develop and contribute
to height rises, resulting in a ridge to build over the western
part of the CONUS. Our area will be downstream of the ridge
axis, and with the addition of another surface high pressure
system over southern Canada, winds will shift to a northerly
direction, and help continue seasonable temperatures. Drier
conditions, and temperatures typical for this time of year are
expected to stick around into next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1222 PM CDT Wed Sep 30 2026

Rain shower activity will continue for the remainder of the
afternoon and evening. The KC Metro and portions of Central
Missouri may see a break this afternoon, but activity should
fill in again through the evening. Isolated thunderstorms are
possible this evening, and then again in the morning. Timing
of strongest showers are hard to pinpoint, but multiple round
are expected. IFR ceilings are forecast overnight and into the
early morning hours of Thursday. Rain activity continues on
Thursday.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...Flood Watch through late Thursday night for MOZ001>008-011>017-
     020.
KS...Flood Watch through late Thursday night for KSZ025-102.

&&

$$

SHORT TERM...Krull
LONG TERM...Bjork
AVIATION...Krull