St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

490
FXUS63 KEAX 251134
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
634 AM CDT Sat Apr 25 2026

...Updated 12z Aviation...

.KEY MESSAGES...

- Scattered Storms Late Saturday Evening

- Severe Storms Forecast Late Sunday Evening into Early Monday

- Another Round of Strong to Severe Storms Forecast Monday

&&

.DISCUSSION...
Issued at 340 AM CDT Sat Apr 25 2026

Most of Saturday morning and afternoon will feature a surface high
pressure that will keep conditions quiet, with light east-southeast
to eventually southeasterly flow. Temperatures will reach the upper
70s by the afternoon, with some locations perhaps hitting the 80
degree mark south of U.S. Highway 50. The middle and upper portions
of the troposphere are featuring multiple perturbations that will
provide multiple days of thunderstorm activity through the weekend
and the start of the next work week.

There is a closed-low system up through 500mb centered over the
Prairie Provinces of Canada and stronger jet streak across the
Northern Plains. The aforementioned surface anticyclone has
developed on the anticyclonic side of this jet streak. A tight H5
height gradient is also present across the desert southwest and
portions of the southern Plains with several short-wave
perturbations. This prompted dCVA over the Rockies promoting surface
cyclogenesis that will force the surface anticyclone eastward, along
with a cold frontal boundary that is currently positioned across
Central Nebraska. The deepening of this surface low will continue
through Saturday afternoon, resulting in surface pressure falls
expanding across the eastern Plains into the lower Missouri River
Valley. This is expected to pull more moisture into the forecast
area through the evening. Convergence should increase after 00z
along with extra mid-level lift from an H5 short-wave trough that
will result in shower and storm activity, though more of it may be
closer to the location of the cold front by the time it arrives in
Central Kansas. CAMs continue to have a corridor of increased
instability into far western Missouri late this evening through the
overnight hours, with 00z HREF mean MUCAPE values between 1500 to
1750 J/kg. A few stronger storms could become possible as the LLJ
strength increases overnight, but the overall better forcing will
remain well west of the forecast area, which will limit the severe
threat, keeping the greater threat over Central Kansas into Sunday
morning. The SWODY1 outlook issued at 06z clips extreme western
Missouri and extreme eastern Kansas with a level 1 marginal risk.
Most of the CAMs dissipate any shower/storm activity east of
Interstate 35 after 09z into Sunday morning. The frontal boundary is
then set to stall across Central Kansas to east-central Nebraska
through Sunday afternoon.

Sunday, strong mid-level vort maxima develops near the Four Corners
region and quickly ejects across the Rockies and into the Plains,
providing stronger dCVA, deepening the surface cyclone in the TX/OK
Panhandle region, with a few localized pockets of extra lift into
the eastern Plains. This will drastically increase theta-e
transport, and transition lower-level flow south to southwesterly
through much of Sunday, and may push the thermal boundary of the
central Plains slightly northeastward through the day. Increased
flow will also increase deep layer shear across the warm sector for
much of the afternoon on Sunday. CAM solutions for Sunday afternoon
continue to show inconsistency with afternoon convective activity,
tied mainly to the timing of available forcing. The 06z HRRR has
developed convection along an area of a localized H5 vort maxima
that tracks from northeast Kansas into Northern Missouri between 19z-
22z Sunday afternoon. The presentation looks as if it may be
elevated along a corridor of isentropic ascent, but a peak at a few
model soundings ahead of this cluster of storms shows robust
boundary layer mixing and steep low-leve lapse rates which could
mean a few surface based storms would be possible. The main question
mark with afternoon peak heating convection though for our forecast
area will be available forcing, as the main thermal boundary will
still be positioned likely over Central Kansas. If afternoon
convection develops in this corridor as suggested by the 06z HRRR,
wind and hail would be the primary threat. Later in the evening, the
primary jet streak begins to move into High Plains, which will shift
the deepening surface cyclone eastward and push the cold front
eastward as well. Convergence will increase heading into the late
afternoon and early hours across the central and eastern Plains.
Across central Kansas, mixing should erode any CIN ahead of the
approaching front and allow for initiation of discrete storms.
Backed surface winds will allow for notable curvature in the low-
level hodographs across central and eastern Kansas, and long
hodographs from 3km and upward will provide sufficient growth for an
initial supercell storm mode. Now for our forecast area, while the
CAPE and shear parameters may be there, the main initiating boundary
will not be close enough, which would greatly limit the potential
for a supercell storm mode by the time the forcing is present in our
far western counties. Some guidance has suggested a few discrete
storms attempting to initiate in eastern Kansas and western
Missouri, but recent trends suggest this is more prevalent over
central Kansas. A more likely scenario will be upscale growth
heading late into Sunday evening, with strong MCS or a few bowing
segments to move through. This all depend on how far east deep
convection initiation occurs Sunday Night, thus uncertainty in the
exact timing for our area is still fairly high. With stronger MCS or
congealed cluster with strong cold pool will present a damaging wind
threat, though larger hail could be spotted in a few of the storms.
While background environment could be supportive of tornadic
development, the likely storm mode for eastern Kansas into Central
Missouri may greatly limit this, with any threat for this being tied
a cold pool balancing and strong 0-3km bulk shear allowing for meso
vortex development. The level 3 enhanced risk for Sunday highlights
the wind threat associated with any upscale growth, and the
conditional threat for supercells if that boundary pushes further
eastward than currently progged before triggering CI.

This creates messy picture heading into Monday, but severe weather
will still remain possible into Monday as the deep surface cyclone
moves through, along with a combination of the cold front and dry
line feature moving eastward. Deep layer flow will still be present
providing plenty of shear over a theta-e rich boundary layer, with
surface dewpoints progged in the mid to upper 60s across most of
Missouri. Remnant outflow boundaries and areas of differential
heating will make for a potentially complex mesoscale environment
heading into Monday afternoon. Depending on the degree of clearing
that occurs from lingering morning convection, new discrete
development could once again produce a few discrete supercells. An
MCV may also not be out of the question, which adds further
complexity. 06z guidance overnight for Monday though is highlighting
a greater risk that is east of our forecast area closer to the
Mississippi River Valley and eastward. This area will also have more
time to destabilize throughout the afternoon. However, most of area
still remains in a level 2 slight risk per the SWODY3 outlook.
Uncertainty in specific details remains high for Monday activity,
but the background environment will be largely supportive of severe
storm development.

The extended forecast does feature additional POPs with a few more
mid-level disturbances that are expected move across the central
CONUS through the remainder of the work week. Uncertain at this
point if any of these setup will present a severe risk.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 632 AM CDT Sat Apr 25 2026

High pressure will keep conditions VFR through the afternoon
with southeasterly winds around 5 to 10 kts. Increasing cloud
cover is likely later in the afternoon. Scattered showers and
thunderstorms are possible in eastern Kansas and western
Missouri late this evening. For now have placed them into a
PROB30 group for STJ and the KC metro terminals.

&&

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

&&

$$

DISCUSSION...Krull
AVIATION...Krull