St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

595
FXUS63 KEAX 301133
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
633 AM CDT Sat May 30 2026

...12z Aviation Update...

.KEY MESSAGES...

- Warm and humid conditions through the weekend with highs near
  to above normal for this time of year.

  - Warmest Sunday/Monday, including possible heat index values
    into 90s for portions of the area.

- Periodic showers and storms continue through the weekend.
  Limited potential for strong to severe storms.

  - SPC Day 1 (Saturday) and Day 2 (Sunday) Marginal Risks for
    portions of the area.

&&

.DISCUSSION...
Issued at 410 AM CDT Sat May 30 2026

The existing Omega Block pattern across CONUS will continue to slowly
evolve over the next few days, and may not fully break down/progress
until mid work week. Given that, the forecast through the weekend
and into early portions of the work week remains fairly messy with
multiple shortwaves and weak mid-upper level flow limiting
confidence in some details. So, with that said, let us try and take
a look at some of the forecast and items to keep in mind.

Currently, a shortwave can be seen nicely on GOES water vapor
imagery moving through central and eastern Kansas. Ahead of this
shortwave, wings of warm air advection/isentropic lift have kicked
of elevated non-severe thunderstorms. SPC mesoanalysis and point
soundings suggest MUCAPE around 1000 J/kg across far western
Missouri, decreasing as you move eastward across the state. Given
the very weak deep shear environment and moist profile (little
DCAPE), risk for near-severe to severe storms is very low. The
strongest of updrafts may be able to briefly produce marginal hail
or a precip loaded down draft, but unlikely. HRRR runs overnight
have significantly backed off on the convection associated with the
core shortwave passage (currently eastern Kansas convection), but it
is of note that most recent runs appear to be under doing current
convection. Whereas the 00z HRRR and surrounding hours appears to be
handling current better. This would suggest clusters of thunderstorm
activity carrying into the KC Metro by around 12z. Again, non-severe
in nature by may be a wet and noisy start to Saturday.

Through the day, scattered non-severe storms may continue, namely
over eastern areas, but attention should actually turn back westward
as another (stronger) shortwave rounds the base of the trough. This
too will induce deeper Lee Cyclogenesis over the Front Range,
helping produce a highly unstable airmass from south-central
Nebraska through Kansas and into Oklahoma. While the immediate area
is not at risk of initial convection, hi-res guidance has shown
various depictions of this activity congealing and drifting eastward
into the area by Saturday evening and overnight. The severe risk
will remain quite limited with unsupportive shear profiles and less
instability. But with PWats >1.75 inches and weak mean winds
(potentially slow storm motions), some flooding/water issues may be
possible. This is also bolstered to a degree with extended hi-res
runs (HRRR/RRFS/NAMnest) depicting areas of >2-4 inches of QPF.
Unfortunately, no real consistency in area depicted at this time.
Suffice it to say it is something to casually keep an eye on. SPC
New Day 1 does have western areas in a Marginal Risk, which will
mainly be dependent on evolution of Kansas convection.

Sunday remains a bit interesting, including the potential for
additional storms. The environment will be more supportive of
strong/severe storm potential with moderate to strong instability
and increasing/supportive deep layer shear, but synoptic models
continue to depict some weak mid-level height rises (general
subsidence) and capping around the 750mb. Previous runs have
remained largely convection free within QPF depictions, but do note
that recent 00z runs of the Euro/NAM/Canadian now suggest convective
initiation after 00z within their QPF output, possibly latching onto
a subtle shortwave or modest dryline just to the NW of the area.
Otherwise may hinge also on cloud cover and/or any remnant
boundaries. Certainly conditional at this point in time. SPC
currently has a Day 2 Marginal Risk over the area and a Slight Risk
just NW into Nebraska. Heat may be of note by this point as well,
with increasing confidence in temperatures climbing toward the upper
80s for western and southern areas of the CWA. Coupled with dew
points in the upper 60s to low 70s, heat index values may pus the
mid-upper 90s. This is most notable for areas near and south of the
Missouri River.

Into the work week, mid-upper level ridging tends to prevail across
central to southern Plains and Mid-Mississippi and Missouri Valley
areas. Drier easterly winds remain forecast by Tuesday and into the
week, pushing bulk of shower/storm potential westward into Kansas.
Temperature conditions Monday potentially very similar to Sunday,
with highs into the mid-upper 80s and heat index values into the 90s
for areas primarily near and south of the Missouri River. After
Monday, relief in humidity as easterly winds advect in lower dew
points.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 629 AM CDT Sat May 30 2026

A messy TAF period for the sites, especially the early and
latter portions of. Currently, waves of showers/storms are
lifting E/NE through the area. An initial wave has already moved
through the sites, with a second wave currently on their
doorstep. Given the scattered nature, have opted for TEMPO -TSRA
vs prevailing, but may be splitting hairs in that regard. Some
lingering additional scattered storms behind this second line
may affect all TAF sites, but have tried to capture that too
with the aforementioned TEMPO. Quieter/dry period through much
of the daytime before expectation for convection to move out of
Kansas tonight. Greatest confidence is north of the KC Metro
sites, yielding PROB30 for the trio in the metro and TEMPO for
KSTJ. During periods of SHRA/TSRA ceilings may drop into MVFR
even IFR.

&&

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

&&

$$

DISCUSSION...Curtis
SHORT TERM...
LONG TERM...
AVIATION...Curtis