St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

829
FXUS63 KEAX 201058
AFDEAX

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

...Updated 12z Aviation...

.KEY MESSAGES...

- Additional Rain Shower Activity Today, More Possible Monday

- Cooler Temperatures This Week

&&

.DISCUSSION...
Issued at 122 AM CDT Sun Sep 20 2026

As of 07z this morning the surface cold front is located from near
Manhattan KS to southeast Iowa. The main convective complex became
outflow dominant, but additional mid-level height falls and
strengthening low-level jet has allowed more thunderstorm to
activity to develop on both sides of the cold front. A few strong
cores are still possible with elevated CAPE present, the strong
outflow boundary from late Saturday Night has greatly worked the
environment over and has helped to stabilize much of the boundary
layer. While main H5 wave moves through, cyclonic vorticity
advection will continue to provide broadscale lift across much of
the lower Missouri River through most of Sunday, maintaining rain
shower chances through most of the day. The main synoptic cold front
should push through during the middle of Sunday morning, perhaps
still producing stronger convergence in our southern and
southeastern zones through the middle of the afternoon.
Redevelopment of stronger thunderstorms may be possible from Bates
County MO to Pettis and perhaps even Cooper Counties. But most of
the stronger activity should then push toward the Interstate 44
corridor and Ozarks Region, while general shower activity continues
into Central Missouri and eastern Kansas. So far rainfall rates have
been fairly light, and should remain this way thus limiting hydro
and areal flooding issues. We will still continue to monitor river
levels and fast responding streams particularly in the KC metro.

By Monday, the surface cyclone and cold front will have cleared the
forecast area, leaving seasonable temperatures for the afternoon.
Deterministic guidance still depicts a closed mid-level mainly over
the upper-Midwest, but some lift may still be possible into the
lower Missouri River Valley. Ensemble suites continue to point to 30-
40 percent probabilities for light rainfall, especially through
Monday late morning and early afternoon. Amongst ensemble members
though, there is larger spread in how expansive the lift is
associated with the feature over the Midwest, and as a result may be
causing higher probabilities over too large of an area. This lift
should move eastward by Monday Night, where conditions will finally
dry out. Through the middle of the week, H5 ridge develops over the
western CONUS and provides northwesterly flow, which will help keep
high temperatures in the upper 60s to lower 70s. Current forecast
remains dry through Wednesday, with the next feature that breaks
down the mid-level ridge progged to move in Thursday when our next
mentionable precipitation chances return to the forecast.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 556 AM CDT Sun Sep 20 2026

This morning will feature IFR ceilings as scattered showers and
mist settles in across the area. Expecting conditions to bounce
between IFR and MVFR for much of the afternoon. We may see
steadier shower development during the middle of the afternoon,
but lack of organization makes timing very difficult to
pinpoint. After sunset this evening, IFR ceilings are likely to
return. Overall aviation conditions will be rough Sunday due to
ceilings and visibilities.

&&

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

&&

$$

DISCUSSION...Krull
AVIATION...Krull