St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

917
FXUS63 KEAX 150448
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
1148 PM CDT Mon Sep 14 2026

.KEY MESSAGES...

- Multiple rounds of storms will bring a flooding risk,
  especially north of the Missouri River, through the middle to
  later part of the work week.

- Round 1 - Monday Afternoon - Evening: There is a Slight Risk
  in far northwestern Missouri. If storms develop/ move into far
  northwestern Missouri, large hail, damaging winds, and
  tornadoes are possible.

- Round 2 - Tuesday Afternoon - Overnight: There is a Marginal
  Risk for severe storms for Tuesday afternoon into the evening
  hours. Strong to damaging wind gusts and hail are the main
  hazards.

- A Flood Watch is in effect from 1 pm Tuesday through 1 pm
  Wednesday as storms become more widespread overnight with
  heavy rainfall likely across northern Missouri.

&&

.DISCUSSION...
Issued at 138 PM CDT Mon Sep 14 2026

The current upper-level pattern consists of a 500-hPa ridge
centered over roughly the Great Lakes region with a shortwave
moving across the Rockies along Canadian border. At the surface,
high pressure is situated over the Great Lakes and lee
cyclogenesis is ongoing in the Northern Plains. A warm front
extending from the surface cyclone is currently (as of 3 PM)
lifting through the KC Metro area and into northern MO. Ahead of
the front, temperatures are in the lower 80s, while temperatures
in the low-to-mid 90s are present behind the front. As such, a
gradient in high temperatures is expected from northeast to
southwest across the CWA today. The pressure gradient between
the high and low pressure centers will be enough to create some
gusty (30-35 mph) southerly winds this afternoon as well.

As the surface cyclone lifts into southern Canada this evening,
a cold front will drop across the Northern Plains towards the
Lower Missouri Valley. This front is progged to stall out across
northern MO and become the focus for multiple rounds of showers
and storms over the next 2-3 days.

The first opportunity for showers and storms comes late this
evening and into the overnight hours across NW MO. An observed
18Z sounding from Omaha depicts 1500 J/kg of MUCAPE, however, a
stout cap is in place over the lowest 1-km. Of note, however, is
that this sounding was taken north of the warm front, so surface
destabilization should occur as the front passes overhead. Model
soundings feature 2000-3000 J/kg of MLCAPE behind the front
with 30-40 kts of deep layer shear. This parameter space is
favorable for organized storm development, however, the best
forcing and shear for storm longevity is focused in eastern NE
and western IA beneath the upper-level shortwave. Aside from far
northwest MO, forcing and shear will be tougher to come by
across the area. As such, the best chances (50-70%) are confined
to areas along and north of US-136.

Within this area of potential storm development, steep mid-
level lapse rates (7-8 C/km) will favor large hail development.
Additionally, 0-1 km shear values of 25-30 kts and cyclonically
curved hodographs will lend to 0-1 km SRH values of 200-300
m2/s2, which point to a potential tornado threat with any storms
that develop. The one caveat here is that most RAP soundings
still show a cap in place, which would limit surface-based
convection and limit tornado potential. As such, uncertainty
remains as to the tornado potential across northwestern MO this
evening, but it is worth noting that the chances are non-zero,
particularly with a warm front in play. But as previous
mentioned, the best parameter space for severe weather looks to
be focused north of the CWA where the SPC Slight (Level 2 of 5)
Risk exists, with all hazards (large hail, damaging winds, and
tornadoes) in play.

Moving into Tuesday, the cold front will move into northern MO
and stall out somewhere around the Missouri River. Sustained
southwesterly flow and 1500-2500 J/kg of MUCAPE atop the front
will lead to storm formation (60-80%) tomorrow afternoon/evening
across northern MO. Deep layer shear will be marginally
favorable (20-30 kts) for storm organization, so the chances for
severe weather are low, but not zero. The bigger concern is for
flooding as the front will be a continued source of lift
through the evening and overnight hours. With PWATs of 2"+, the
current forecast calls for 1-3" of rain across northern MO
tomorrow night, with locally higher amounts possible. This, on
top of the 5"+ that many areas received this morning, will set
the stage for a potential flooding threat. To account for this,
a Flood Watch has been issued for areas along and north of US-36
and west of US-65 from 18Z tomorrow through 18Z on Wednesday.
It is not out of the question that the watch will need to be
expanded south, but have kept the KC Metro out for now.

Areas south of the cold front across central MO tomorrow will
see another seasonably hot day with temperatures climbing into
mid-to-upper 90s with heat indices approaching 105 degrees.
Given cloud cover and a front in play, have opted to hold off on
a Heat Advisory with this forecast cycle, but one may be needed
for tomorrow afternoon across the far southern portion of the
CWA.

The stalled front is expected to lift back to the north as a
warm front on Wednesday bringing highs in the upper 80s and
lower 90s back to northern MO over the next few days. Current
long range model guidance depicts another shortwave moving
across the Northern Plains towards the end of the week. A
surface cyclone will accompany this shortwave, which will push a
cold front across the Central Plains and bring cooler
temperatures (highs in the 70s) to the area. However, a good
amount of uncertainty remains with this forecast given
differences in the empirical models at this range.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1144 PM CDT Mon Sep 14 2026

Showers and thunderstorms are expected to increase across
northwest Missouri after 09Z this morning building southward
with time along a slow moving cold front. Storms are expected to
become more numerous after 21Z, potentially producing gusty
winds and heavy rainfall. Ceilings are expected to lower north
of the boundary across northern and western Missouri into the
MVFR range, with potential spot in the IFR category.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...Flood Watch from Tuesday afternoon through Wednesday afternoon
     for MOZ001>006-011>015-020>022.
KS...Flood Watch from Tuesday afternoon through Wednesday afternoon
     for KSZ025-102.

&&

$$

DISCUSSION...Carothers
AVIATION...BT