St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

851
FXUS63 KEAX 211124
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
624 AM CDT Fri Aug 21 2026

.KEY MESSAGES...

- Seasonably hot today, with afternoon high temperatures in the
  upper 80s to lower 90s.

- Chance (30%) for showers and thunderstorms late this
  afternoon into this evening. If there are storms, they may be
  strong to severe, with damaging wind gusts being the primary
  hazard.

- Cooler temperatures are expected Saturday and especially
  Sunday.

- Rain chances (30 to 40%) return late Sunday night into Monday
  morning.

&&

.DISCUSSION...
Issued at 317 AM CDT Fri Aug 21 2026

Eastern Kansas and Western Missouri remain beneath northwesterly
flow aloft situated between a 598 dam H5 high centered over the
Four Corners with associated ridging across much of the western
CONUS and broad longwave troughing across the northeastern US.
At the surface, high pressure has yielded clear skies and nearly
calm winds. Some patchy fog may be possible this morning,
especially closer to sunrise. Higher mid level heights will move
in from the southwest today, helping push afternoon highs into
the upper 80s to lower 90s for most locations. A subtle
disturbance and vort max embedded within the northwesterly flow
aloft toward the northeasterly periphery of the ridge is
projected to translate northwest to southeast across Nebraska
this afternoon, which may initiate convection across eastern
Nebraska by mid afternoon. If this happens, this could
potentially grow upscale into an MCS and enter into NE Kansas
and NW Missouri by late afternoon/early evening, where CAMs suggest
over 2500 J/kg of ML CAPE along with around 35 knots of deep
layer bulk shear capable of sustaining robust convection
(although convective inhibition may be strong enough to choke
out the storms as they move toward/into the region). One
interesting thing to note is that the 6z HRRR suggests an MCS
developing across SE Nebraska, diving to the south southeast
into western portions of the CWA by late afternoon and into the
evening hours, with a relatively wide swath of strong winds.
This will be something to watch closely as we progress through
the remainder of the morning hours and into this afternoon. At
this time SPC has maintained a marginal risk for severe storms
across the entire CWA. Additional convection is possible
overnight tonight into early Saturday morning, but higher PoPs
should remain west of the CWA across eastern KS.

Higher amplitude troughing is progged to dig into the Great
Lakes and Ohio Valley on Saturday, helping send a cold front
north to south through the CWA. This will help cool temperatures
a bit, with Saturday afternoon highs forecast to reach the mid
80s for most locations. Even cooler temperatures are likely for
Sunday, as well as drier air filtering in from the north, with
dew points only in the lower to mid 60s. Rain chances return to
the region late Sunday night into Monday morning as a subtle
shortwave is projected to translate through the northwesterly
flow on the northeastern periphery of the upper ridge. Warmer
(but seasonal) temperatures and increased moisture returns for
Monday and into the middle of next week

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 619 AM CDT Fri Aug 21 2026

Light and variable winds at all terminals this morning, with VFR
conditions under clear skies at the KC metro terminals but MVFR
VIS at STJ due to fog. Fog should mix out by 14z this morning at
STJ, returning conditions to VFR. Otherwise, light and variable
winds and VFR conditions should continue at the terminals
through the vast majority of the period. There will be a chance
for showers and thunderstorms at the terminals this evening,
generally between 00z and 03z, so have introduced a PROB30 for
this. If storms do impact the terminals, there may be brief
reductions in VIS as well as brief periods of strong wind gusts.
Showers may be possible once again overnight tonight into early
Saturday morning, but for now confidence is too low to include
in the 12z TAF issuance.

&&

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

&&

$$

DISCUSSION...BMW
AVIATION...BMW