St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

340
FXUS63 KEAX 251148
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
648 AM CDT Fri Sep 25 2026

.KEY MESSAGES...

- Showers make their way into the area, sticking around for the
  weekend with accumulations around 0.5-1.25 inches.

- Potential for non-severe isolated thunderstorms and locally
  heavy rainfall across the area.

- Short dry period early next week before another disturbance
  brings more rain into mid next week.

&&

.DISCUSSION...
Issued at 328 AM CDT Fri Sep 25 2026

Showers from western KS are continuing to develop as we start off
our rainy weekend. Throughout the day, 500mb heights will continue
to fall over our area as the shortwave makes its way east and
southerly flow at the surface will increase as high pressure moves
off to our NE and low pressure develops to our west. Synoptic scale
lift could support some isolated thunderstorms while moisture
transport could support locally heavy rainfall but storms should
remain sub-severe as low-level clouds and weak low-level lapse rates
will limit instability. These conditions will stick around for the
weekend as a blocking pattern develops at 500mb with high pressure
over the Great Lakes is sandwiched between the Nor`easter developing
off of the Atlantic coast and the mid-level trough over the Pacific
NW and Western Canada. As a result, we could see rain accumulations
this weekend of 0.5 inches along I-70 and increasing amounts of up
to 1.25 inches for NW MO. Deterministic guidance has showers
clearing out Sunday afternoon but how quickly showers clear out will
depend on how the blocking pattern develops. An upper-level ridge
tries to build back into our area Sunday but it will have to fight
the Nor`easter that looks to set up shop over the North Atlantic
Coast. As a result, showers could potentially stick around for a
little while longer.

As long as the ridge can progress east, as models currently suggest,
we should dry out briefly Monday before we see the potential for
more rain in the middle of next week. Monday night into Tuesday,
there is another 500mb trough that deepens along the California
coast and a tropical system moving towards the Baja California
Peninsula. Models show these two low pressure systems coming
together over the SW US sometime between Tuesday and Wednesday. The
systems then continues to progress east, bringing strong moisture
transport into our area with strong, moist southerly flow from the
Gulf at the surface and the tropical system brings moisture
transport aloft, making for a very moist atmospheric profile. As a
result, deterministic guidance currently has PWAT values around 2
inches over MO for Wednesday which is in the 99th percentile for
this time of year so we will continue to monitor how this system
progresses over the next couple of days.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 629 AM CDT Fri Sep 25 2026

Showers continue to move through the area but there is a 30-40%
chance ceilings drop to MVFR north of I-70 but it will depend
on how far south the heavier showers progress. Showers will
shut off this evening but there may still be some lingering
isolated showers. Rain will pick back up overnight around 4-6Z
but MVFR CIGS will stay contained to north of US-36. Winds will
remain light out of the ESE through the period.

&&

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

&&

$$

DISCUSSION...IPC
AVIATION...IPC