St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

198
FXUS63 KEAX 300240
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
940 PM CDT Wed Jul 29 2026

.KEY MESSAGES...

- Showers and isolated thunderstorms are possible (30 to 50
  percent chance) Thursday morning, mainly west of U.S. Highway
  65.

- There is a good chance of thunderstorms Thursday night into
  Friday morning across the area. An isolated severe storm is
  possible, mainly in northwest Missouri and far northeast
  Kansas. Locally heavy rainfall is also possible.

- Cooler and less humid conditions are expected for the weekend.

&&

.UPDATE...
Issued at 929 PM CDT Wed Jul 29 2026

Storms have finally diminished this evening in northwest
Missouri and far eastern Kansas. The latest convection-allowing
models have remained consistent in bringing in decaying storms
from eastern Kansas Thursday morning (around/after daybreak),
mainly affecting areas west of U.S. Highway 65 (and possibly not
much farther east than the KC metro area). Have refined PoPs
through Thursday morning based on latest model trends.

It seems apparent from this evening`s CAMs that convection is
quite likely (better than 65% chance) across the forecast area
tomorrow night into Friday morning as a mesoscale convective
system moves southeastward into/through the region. Chances for
severe weather, while low, are not zero, as storm organization
upstream may allow for some severe wind gusts with the
progressive cold pool(s) moving into the region late in the
night. Heavy rainfall is also possible given the anomalous
moisture remaining across the region; however, the progressive
nature of the storms seems likely to mitigate the flooding
threat to some degree. Raised PoPs after midnight Thursday night
through Friday morning across the region based on reasonably
good consensus amongst the CAMs this evening.

Finally, isolated to scattered storms may redevelop Friday
afternoon as an attendant low moves through the central Plains.
Best chances for this appear to be east of U.S. Highway 65. The
environment would be favorable for severe weather, with damaging
winds and a tornado or two the most likely threats. However,
given the fairly progressive nature of the system, chances
appear higher to the east of the forecast area.

&&

.DISCUSSION...
Issued at 145 PM CDT Wed Jul 29 2026

For this afternoon, a weakening MCV, evident in the diminishing
radar returns, is slowly tracking to the southeast. This may
bring spotty showers and storms to eastern KS and western MO for
the remainder of the afternoon, but it seems likely that the
diminishing trend will continue with most areas staying dry to
only seeing a trace of precipitation. Otherwise, overnight and
into tomorrow morning, another area of showers and storms looks
possible as the overall setup is similar. In a very moist
atmosphere, with PWAT values near/just above 2" in eastern KS
and western MO, at the interface of the surface high to the
east, and weak mid-level flow aloft, an area of weak isentropic
ascent sets up. This should provide just enough ascent to lead
to precipitation development. This may be aided by any upstream
convection and potential MCV that isn`t readily apparent in any
model depiction yet, or even generated yet. The RAP does hint
at some of this potential with some internal PV noted from
600-400mb. Such is forecasting on the east side of the upper
ridge within weak/modest northwesterly flow.

A stronger shortwave trough will track across the northern edges of
the upper ridge Thursday evening and overnight. Forcing
associated with this shortwave should lead to an area of storms
developing to our northwest, that then tracks southeastward with
time, affecting the forecast area Thursday night to Friday
morning. Models show modest instability and shear into the area
through the overnight hours. Given this, and the propensity for
northwest flow convective systems to track further southeast
than anticipated, a few strong to marginally severe storms look
possible for northeastern KS and northwestern MO, in this
pattern.

In the wake of this system cooler and much drier air will settle
into the area. Dewpoints in the low to mid 60s Saturday and Sunday
will be a welcomed relief compared to the low to mid 80 degree
dewpoints we experienced last weekend.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 633 PM CDT Wed Jul 29 2026

Aside from storms near STJ early this evening, the TAF sites
should be mainly VFR with east to southeast winds 5 to 10 kt
through the overnight hours. Convection to the west will
approach the terminals after 10z Thursday, but should be in a
weakening state as precipitation approaches the TAF sites. For
now, have kept thunder mention out of the TAFs and kept VFR
showers from roughly 10z to 16z Thursday. During the afternoon,
any lingering precipitation should dissipate, with VFR and
southeast winds around 10 kt continuing. A better chance of
storms exists Thursday night into Friday morning.

&&

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

&&

$$

UPDATE...CMS
DISCUSSION...CDB
AVIATION...CMS