St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

389
FXUS63 KEAX 211125
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
625 AM CDT Tue Apr 21 2026

.KEY MESSAGES...

- Above normal temperatures and breezy south southwesterly winds
  are expected today through Thursday.

- Shower and thunderstorm chances return Thursday afternoon into
  Friday as a cold front is projected to move through the
  region.

     - Strong to severe thunderstorms and locally moderate
       rainfall will be possible.

- Unsettled weather looks likely to continue into the weekend,
  with additional chances for showers and thunderstorms,
  especially Sunday afternoon into Monday morning.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 146 AM CDT Tue Apr 21 2026

Current H5 analysis shows ridging across much of the west
central CONUS, however a subtle shortwave with a weak lobe of
vorticity is currently translating within the northwesterly flow
aloft over the Dakotas. At the surface, a relatively shallow
surface low is analyzed over western Minnesota, with an
attendant cold front trailing to the west southwest. With a
tightening pressure gradient, enhanced south southwesterly
winds have continued into the overnight period, with sustained
winds on the order of around 15 mph and gusts up to 25 mph, and
this increased low level southerly flow has continued to advect
increased moisture into the region throughout the evening and
into the overnight hours. All of these factors have yielded much
warmer temperatures this morning compared to those of the
previous few mornings, with 3 AM temperatures ranging from the
mid 50s to around 60 degrees.

The aforementioned subtle shortwave will continue to translate
to the southeast through the day today, with the shortwave axis
extending from roughly Lake Superior into central Illinois by
this evening. This will push the cold front further south and
east toward our CWA, extending roughly west to east across south
central Iowa into northern Illinois by this evening, with an
axis of 1000 to 1500 J/kg of CAPE developing ahead of the front
across northern Missouri. This will yield about a 10% to 20%
chance for an isolated shower/thunderstorm this evening across
far NE Missouri. Aside from these low end PoPs across NE
Missouri, well above normal temperatures are expected today
(highs ranging from mid 80s across NW Missouri to the upper 70s
elsewhere) as well as 15 to 20 mph SW winds gusting up to 30
mph. Moisture return will continue throughout the day, with dew
points rising into the mid 50s by this afternoon.

The western mid/upper trough is projected to enter into the
western CONUS by late tonight, reaching the Intermountain West
by Wednesday afternoon with mid/upper ridging continuing over
our CWA downstream. Warm temperatures (although a few degrees
cooler than today) and breezy south southwesterly winds should
continue, with highs in the mid to upper 70s.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Issued at 146 AM CDT Tue Apr 21 2026

On Thursday, broad longwave troughing will remain anchored
across the western CONUS, with the initial shortwave lifting to
the northeast across the Northern Plains and into Canada.
Meanwhile, a lower amplitude wave is progged to cross the
Southern Rockies and move into the South Central High Plains by
Thursday evening. This will yield increased southwesterly deep
layer flow over the CWA by Thursday afternoon. At the surface, a
strong surface cyclone should develop over North Dakota by
Thursday morning, moving northeastward into southern Manitoba
throughout Thursday afternoon and evening, with an attendant
cold front extending southward into central Kansas, linking up
with a secondary surface low with a southward extending dryline
into western Oklahoma and the Texas Panhandle.

Strong southerly low level flow should develop out ahead of
these features across our CWA on Thursday afternoon, with gusts
up to 30 to 35 mph. Continued moisture advection should send
dew points into the lower 60s (perhaps even mid 60s across the
KC metro and points south and west), and with temperatures
reaching the upper 70s by mid afternoon, MU CAPE is projected to
range from around 1250 to 2000 J/kg Thursday afternoon into
Thursday evening. This will be paired with around 30 to 35 knots
of deep layer bulk shear, allowing for relatively well
organized updrafts capable of producing severe weather. Mid
level height falls along and ahead of the approaching cold front
should initiate storms sometime Thursday afternoon, likely west
of our CWA across SE Nebraska into eastern Kansas. Storm mode
may be initially discrete or semi discrete, but with mid level
flow mostly parallel to the front, storms will likely grow
upscale into one or more linear segments as they move eastward
toward our CWA. The new SPC Day 3 Convective Outlook places NW
Missouri and NE Kansas within the slight risk (basically along
and west of Interstate 35 from the Iowa border to KC and into
Linn County KS), with a marginal risk for the remainder of the
CWA.

In addition to the severe potential, models suggest a plume of
1.25 to 1.5" PWATs ahead of the front, which may promote locally
moderate rainfall. WPC continues to highlight the entire CWA
within a marginal risk for excessive rainfall. The most recent
NBM run gives around a 20 to 30% chance for rainfall to exceed
1" across NE KS into NW Missouri, with around a 50% chance
across the KC metro, peaking at around 60% southeast of the KC
metro. The cold front should move through the region from
northwest to southeast overnight Thursday night into Friday
morning, although some guidance is once again suggesting that
the front may not completely clear the CWA (such as the 00z
GFS), with continued shower and thunderstorm chances into Friday
afternoon.

As we head into the weekend, models suggest the potential for
yet another trough moving across the western CONUS and entering
into the Plains Sunday morning and ejecting across the central
CONUS Sunday afternoon into Sunday night. This would keep shower
and thunderstorm chances in the forecast, especially for Sunday
into Monday morning (peaking around 70% PoPs for 7 PM Sunday
through 7 AM Monday). Locally moderate rainfall may be possible
once again during this period. Near normal temperatures (highs
ranging from the mid 60s to lower 70s) are favored for Friday
through Monday.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 615 AM CDT Tue Apr 21 2026

Currently VFR at all terminals with only some passing high
clouds and 15 knot south southwesterly winds gusting up to 25 to
27 knots. These conditions should generally persist through the
daytime hours today, with winds and gusts decreasing just a bit
tonight into the overnight hours. Gusts should relax by around
9z to 10z Wednesday morning, with MVFR CIGs potentially
developing.

&&

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

&&

$$

SHORT TERM...BMW
LONG TERM...BMW
AVIATION...BMW