St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

241
FXUS63 KEAX 150846
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
346 AM CDT Wed Apr 15 2026

.KEY MESSAGES...

* Active weather pattern continues with multiple additional chances
  for strong to severe thunderstorms, today/Wednesday and Friday.
  - Today/Wednesday: SPC Day 1 Slight Risk
  - Friday: SPC Day 3 Enhanced Risk

* Warm temperatures (upper 70s to low/mid 80s) are expected to
  persist through the work week, then cooler and drier
  conditions expected this weekend and into early next week.

&&

.DISCUSSION...
Issued at 344 AM CDT Wed Apr 15 2026

What looked to be a fairly potent setup for strong to severe storms
in the area yesterday evening and into the overnight tended to
struggle mightily. By the evening, moisture rapidly surged northward
toward and into portions of Nebraska and Iowa and the dryline rapidly
retreated westward. Further SW, convective initiation ended up quite
a bit further south (well into Oklahoma) than prior expectations.
With the otherwise overall lack of synoptic level support/lift, this
resulted in initial clusters of strong to severe storms over
Nebraska/Iowa that just clipped northern Missouri and little to no
precipitation into southern portions of the CWA with trajectories
keeping activity into Springfield`s area. This through about 3am. As
of this writing, elevated non-severe convection continues to drift
eastward across northern Missouri, with no expectation for anything
more. Additionally, elevated convection is now seen blossoming over
south-central to SE Kansas, along the nose of strong ~850mb moisture
advection and the general LLJ. Of note, HRRR runs have not tended to
handle this new KS convection well with all but the most recent run
or two holding off on anything budding until just NE of the KC Metro
around/after 10z. This leads to limited confidence in convective
trends to round out the overnight and into the morning/commute
hours. Conceptually, given what is transpiring and the environment
depicted on SPC Mesoanalysis, tend to expect this scattered elevated
convection to lift into the forecast area from SW and potentially
increase in general coverage as it does so. Fortunately, soundings
(ACARS and model) depict a reestablished cap which will help
drastically limit top end potential. If anything, these
thunderstorms may further prime some locations for possible local
flooding or river issues later today/tonight. This general activity
should drift NE through the morning and yield a mostly cloudy and
moist/humid day.

Normally morning convection and cloud cover would give rise to
recovery concerns, but persistent moderate to strong moist low level
flow should have no issue re-priming and mixing the area. Especially
with moderate to steep mid-level lapse rates remaining in place. So,
how do we fell about this afternoon and evening given what how
forecasts have gone the last couple of days? That is a fair
question. A notable difference today is that more
substantial/supportive synoptic lift approaches as well as a more
progressive frontal boundary as the western trough continues to kick
out into and across the Plains with its attendant surface low. So,
convective initiation is probably least of the uncertainties,
overall. Instead, questions tend to be more around when does
convection first fire off this afternoon, is any of it
discrete/ahead of the cold front, how quickly it may grow
upscale/cluster/linear, etc. Those timing and, more importantly,
storm mode answers will determine the most prevalent threats. As you
would imagine, discrete convection would carry an all hazards
threat, especially large hail and damaging winds. Right movers would
potentially yield very supportive low level inflow that could yield
the best opportunity for a tornado or two. Clustering or more linear
modes, including along frontal passage, would transition threats
more toward damaging winds and occasional hail. For reference,
broad set of guidance suggests >2000 J/kg MLCAPE, >40-45 kts deep
shear. If the cold front was less progressive, mean wind/deep shear
orientation would be more concerning for training storms/flooding
issues, fortunately that does not set up to be the case here.
Activity as early as around 1pm and up to around the evening commute
in the KC Metro and 9-10pm for eastern parts of the forecast area.

Brief break in activity Thursday as the upper trough moves east and
a bit drier air mass moves in, but temperatures remain seasonally
warm in the 80s with southerly flow quickly returning. This helps
set the table too for Friday which will be yet another chance, quite
possibly our best during this stretch, for severe thunderstorm
activity. By Friday, another western CONUS trough, currently moving
down the coast of British Columbia/approaching Washington/PNW, will
be pushing across the Intermountain West and induce rounds of Lee
Cyclogenesis along Wyoming and Colorado Front Ranges. Conceptually
this checks most the boxes as it is a pretty deep/sizable trough
that begins to pivot/take on a neutral to negative tilt across the
region. Robust/deep southerly flow ahead of this too will push
surface dew points back into the mid 60s and steep mid-level lapse
rates may push SB/MLCAPE values >2500-3000 J/kg. Wind profiles again
look favorable for an all hazards situation with discrete
convection. Synoptic scale lift support, frontal passage, and
potential jet position start to check of additional boxes as well.
Suffice it to say while you cannot necessarily hang your hat on the
details just yet, Friday is a day to pay attention to. Bolstered by
the previous Day 4 30% and the New Day 3 Enhanced by the SPC for
much/most of the area.

In the wake of this Friday system/threat, a period of quieter
weather and cooler/more seasonable temperatures looks to settle in
as NW mid-upper level flow and eventual height rises/ridging
dominates. This should be through the weekend and at least into
early next week before any notable precipitation chances attempt to
return.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1223 AM CDT Wed Apr 15 2026

TAFs continue to be somewhat messy and uncertain. MVFR ceilings
do look likely across the TAF sites late in the current
overnight, lingering into late morning/early afternoon before
they mix/lift back into VFR. The more uncertain and messy aspect
though continues to be convective trends and timing. It is
possible to see some budding scattered convection around/after
10z this morning, with genesis near to just E/NE of
KSTJ/KMCI. That has been accounted for with a VCTS mention for
that time period, and one can expect any activity in their
vicinity to pretty quickly drift E/NE. The afternoon/evening
convection potential is more certain, but timing remains a bit
in flux. With that part in mind, have opted for a TEMPO period
to indicate the current best window for storms ahead of and
along the frontal passage. VFR conditions return quickly
thereafter by around 00z.

&&

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

&&

$$

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