St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

814
FXUS63 KEAX 131116
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
616 AM CDT Mon Apr 13 2026

.KEY MESSAGES...

* Active weather pattern continues with multiple chances for strong
  to severe thunderstorms.

  - Best chance for strong to severe storms Tuesday evening/night,
    Wednesday afternoon/evening, and Friday afternoon/evening.

* Generally seasonally warm and humid through the work week.
  Cooler and drier (less humid) into the weekend.

  - Highs upper 70s to 80s through Friday, then mid-50s to 60s
    into the weekend.

&&

.DISCUSSION...
Issued at 403 AM CDT Mon Apr 13 2026

SW large scale flow/pattern is well established through the central
CONUS as a western trough continues to down the California coast and
toward the SW CONUS. Closer to the immediate area surface pressure
continues to build and glide off the Colorado Front Range in
response to shortwave moving through the mean flow. This has worked
to increase surface/near surface flow locally (gusting into 20s kts
currently), and effectively surging additional WAA/moisture up into
and through the Southern and Central Plains. While potent ~19-20 deg
C cap/EML is being advected into the area currently, a few elevated
showers/general thunderstorms will be possible this morning on the
nose of a 40-50+kt LLJ and steep lapse rates above the cap/EML. This
activity/potential has been seen on GOES Nighttime Microphysics
products (convective clouds above the stratus) and most recently
with budding returns on local WSR-88D. Nothing to see here given the
highly elevated nature and limited instability with which to work
with. A few flashes of lightning and rumbles of thunder. This
activity drifts NE through the morning, with some potential uptick
in coverage as it exits the forecast area into SE Iowa and far NE
Missouri.

For the remainder of the day, if you just looked at the parameter
space there would be concern for some robust convection. Fortunately
though, the well advertised strong capping/EML will be in place.
There are some indications the cap weakens and in some cases nearly
erodes by around 00z, but without a clear mechanism for lift it
remains unlikely for any surface based convection to be achieved.
Through the day, it is possible to see a few elevated showers with
depictions of near dry adiabatic lapse rates atop the cap/EML and
ongoing WAA/moisture advection through at least the lower levels. In
the unlikely event that something surface based is able to be
achieved (strong enough differential heating if prolonged pockets of
sunshine are achieved? sun angle too low?), environment will would
be supportive of organized and robust convection. Through the day,
conditions too will be quite windy and have upped winds over
baseline NBM, coming more in line with recent CAM runs/guidance.
Current expectation for sustained winds 15-20+ mph and gusts 25-35
mph. Into the overnight surface winds remain up, and a few elevated
showers remain possible as LLJ picks up.

Instead, Tuesday continues to be the better of the immediate days
for strong to severe potential over the area. As the larger SW Conus
trough continues to work into the Intermountain West, it will eject
another shortwave into the flow and trigger another round of Lee
Cyclogenesis. This surface low will move off the Front Range further
south than the Monday iteration, building into/tracking over C/NE
Kansas. While EML will initially be of similar strength/magnitude,
ongoing WAA and typical diurnal mixing will help yield a notably
weaker CAP. Surface temps to be a handful degrees warmer than
Monday, into the mid 80s. Parameter space wise, hi-res/CAM guidance
in fair agreement on >1500-2000 J/kg SB/MLCAPE and >35-40 kts deep
shear. Now, will we be able to break the CAP locally and achieve
discrete convection... that is the question. There remains a lack of
substantial lift locally. And while the dry line moves toward
eastern Kansas, guidance is not excited about initiation immediately
to our west. Instead,CAM runs remain quite consistent in the CAP
breaking over N Oklahoma and S Kansas by around mid-afternoon and
that activity moving NE with the mean flow. Should this solution
prevail, our severe threat most likely revolves around a wind and
hail threat. The northward extent of activity may also be dependent
on the evolution of the surface low and how far E/NE the drier air
is able to move, and that is of course depicted near the KC Metro in
some cases. So we will continue to keep an eye on that. The Slight
Risk within the new SPC Day 2 Outlook is very reasonable given the
parameter space and the uncertainties at hand.

Activity may continue into overnight Tuesday into Wednesday with
persistent strong WAA/moisture advection and increasing LLJ, but
with more limited severe potential. The strong to severe potential
Wednesday hinges largely on how the atmosphere is or is not able to
recover/destabilize as overnight activity and cloud cover may/likely
continue into the daytime Wednesday. The most likely area of concern
may be back near/along the approaching dry line/front and as the
western CONUS trough moves out into the Plains and provides more
robust lift and deep shear. The SPC Day 3 Slight over much of the
area too is reasonable.

Quieter, but still warm, conditions prevail Thursday as trough
departs eastward and mid-upper ridging moves in behind. But, the
hits keep on rolling though as the overall active pattern continues
as storms return Friday. Whether it be activity lifting out of the
Southern Plains or along/ahead of an approaching cold front. Quick
peek at conditions does suggest another at least semi-favorable
parameter space and is reflected in the SPC Day 5 15% risk.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 612 AM CDT Mon Apr 13 2026

Low-MVFR to IFR conditions will kick off the TAF period as
WAA/moisture advection continues to overspread stratus into the
area. These ceilings will lift through the morning, eventually
yielding a return to VFR ceilings by late morning to early
afternoon. Overall cloud cover will tend to continue into the
afternoon/evening, but on the order of 20kft or so. Winds will
remain pretty unidirectional through the day, out of the SSW/SW,
and gusty. Sustained winds upwards of 20kts and gusts into the
low 30s kts through the daytime, and only marginally easing into
the Monday overnight time frame. A few widely scattered
showers/isolated thunder may be possible during the period, but
confidence and coverage well below any threshold to put in a
prevailing mention.


&&

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

&&

$$

DISCUSSION...Curtis
AVIATION...Curtis