St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

398
FXUS63 KEAX 122337
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
637 PM CDT Sat Sep 12 2026

.KEY MESSAGES...

- Strong to severe storms are possible tonight across eastern Kansas
and western Missouri with large hail and damaging winds the main
threats. In addition. heavy rainfall is expected which  could lead
to localized flooding.

- Numerous rounds of showers and storms, particularly for
  northern Missouri, appear possible next week, with widespread
  cumulative heavy rain possible.

- Well above normal temperatures look likely again Monday and
  Tuesday with highs in the low to mid 90s and heat index values
  in the 100-105 range generally south of the Missouri River.

&&

.DISCUSSION...
Issued at 151 PM CDT Sat Sep 12 2026

Morning showers and thunderstorms have made for a tricky
forecast as to how afternoon/evening convection will unfold.
Outflow from this morning`s storms which has become the
effective boundary has pushed south of the area. This will be
where the best chance for more organized severe storms will be
however, the actual surface front is currently bisecting the
area and may be the focus for additional storm development this
afternoon/evening. Hi-res guidance suggests storm development
may be forced by a mid-level shortwave moving through the area
on zonal flow aloft. However, model guidance does differ on
timing and intensity of this shortwave feature. Storms are
expect to develop in an area of 1500-2000J/Kg of MUCAPE and
40-45kts of effective shear. This will be sufficient for strong
to isolated severe storms capable of producing large hail up to
ping pong ball size and gusty to damaging winds to 60mph. Storm
coverage is expected to increase in coverage and perhaps
intensity (after a brief diurnal weakening trend) around
midnight as a nocturnal 35-40kt southwesterly LLJ noses into
the area. These storms will be very efficient with PWAT values
around 2 inches so, if even brief training occurs localized
flooding would be a concern. Storms will persist through the
overnight into Sunday morning until the LLJ weakens and veers
off to the east. At this time Sunday afternoon looks mostly dry
although a few scattered showers (20-30%) may linger across the
eastern CWA. Highs Sunday afternoon will range from the lower
70s north to mid 80s south. By tomorrow night, the surface front
that moved through the area today will reside south of the CWA.
Again a nocturnal LLJ will develop and override this boundary
producing additional showers and thunderstorms across the area.
Severe potential looks low at this time however, heavy rain may
again be possible with PWATs remaining around 2.00 inches. This
may lead to additional flooding concerns. Showers may linger
into Monday morning as the frontal boundary lifts north across
the area as a warm front. This will set up the area for a very
warm day on Monday as strong WAA ushers in temperatures rising
into the mid 80s to mid 90s with heat index values over the
southern CWA rising to 100-105.

Monday night into Tuesday, a upper level trough will move from the
northern Plains into the northern Great Lakes. This will force a
weak trailing cold front into the area on Tuesday. The local area
will be on the periphery of a upper level ridge over the
southeastern CONUS. Models through the middle of next week bring
unsettled weather to the area...depicting several shortwaves
rounding the upper level ridge and bringing rounds of showers and
thunderstorms to the area with the stalled surface front over the
area being the focus for storm activity. while severe potential
looks low at this time, several rounds of storms are expected to
produce 2-4 inches of rain across northern Missouri which may lead
to flooding concerns. While the stagnant upper level pattern does
break down late next week it does come courtesy of an upper level
trough moving from the central Plains and through the local area
which would keep the pattern unsettled.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 630 PM CDT Sat Sep 12 2026

Dry air in the near surface layer may result in gusty winds from
showers and thunderstorms across eastern KS into western
Missouri in the next few hours. Additional storms are expected
to develop after dark tonight though gust potential should
gradually decrease throughout the night. Confidence in
precipitation not high enough to include at this point for STJ
terminal.

&&

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

&&

$$

DISCUSSION...73

AVIATION...BT