St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

219
FXUS63 KEAX 152326
AFDEAX

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

.KEY MESSAGES...

- Strong to severe storms are expected to develop this afternoon
  and evening, with the best chances south and east of the I-35
  corridor. Damaging winds and large hail are the primary
  threats, though isolated tornadoes cannot be ruled out.

- Another round of severe weather is anticipated on Friday
  afternoon and evening, with all severe hazards possible.
  Confidence is higher than average that widespread coverage of
  storms is expected. Confidence is lower on convective mode,
  which will have significant influence on what severe weather
  hazards will occur with the storms. Stay tuned to the latest
  forecasts.

- Much cooler weather is expected this weekend. Low temperatures
  on Saturday night may approach the freezing mark in northern
  Missouri.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 204 PM CDT Wed Apr 15 2026

Primary concern in the short term is severe-weather potential
this afternoon/evening. A weak surface low in eastern Nebraska
and western Iowa with an attendant cold front extending
southward through eastern Kansas will shift
eastward/northeastward this evening. Prompted by large-scale
lift from an approaching perturbation this afternoon, convection
is expected to initiate rapidly through late this afternoon
(storms already developing in southeast Kansas as of 2 pm).
Convection-allowing models (CAMs) have been consistently
developing initially discrete convection along the front roughly
near the I-35 corridor, growing quickly upscale into
clusters/lines as the storms progress quickly
eastward/northeastward through early evening.

Large hail will be the primary threat with discrete storms,
with wind damage becoming more possible with time as storms grow
upscale. Wind profiles are generally favorable for splitting
supercells (confirming the large hail threat), but mean
mid/upper flow is largely parallel to the approaching front.
Storm interactions should be frequent as more and more cells
develop, so the process of congealing may be quite fast. This
would likely mute the tornado threat, but the risk is not
negligible. Low-level shear is more than adequate for tornadoes,
and LCLs lower from west-to-east across the forecast area (and
are sufficiently low everywhere).

The good news is that the storms will be progressive, so the
flooding risk is low today. The storms should generally be out
of the forecast area by 9 or 10 pm, with the rest of the night
expected to be dry. With the Pacific origins of today`s weather
system, Thursday should continue the streak of warm days (highs
mainly in the 80s), with shortwave ridging keeping things dry
(continuing through Thursday night).

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 204 PM CDT Wed Apr 15 2026

Primary concern is the severe-weather episode expected on Friday
afternoon/evening.

A deepening longwave trough in the western U.S. will slowly
approach the northern/central Plains Friday. A predecessor
vorticity maximum will eject northeastward into the Missouri and
Mississippi Valley regions Friday afternoon/evening, in advance
of a strong cold front moving southeastward from the northern
into the central Plains. Substantial large-scale lift will be
present (via warm advection and differential cyclonic vorticity
advection) as the cold front approaches north/west portions of
the forecast area Friday afternoon. Storms will rapidly develop
during the afternoon along the front. Thermodynamic and
kinematic profiles will be very favorable for severe storms, but
the extensive nature of the large-scale lift and the largely
parallel upper flow to the surging front suggests storm
interactions will be rapid, resulting in quick upscale growth
into an extensive line of storms with time. Damaging winds and
QLCS tornadoes are possible as the line develops/matures, with
large hail and isolated tornadoes the main threats during the
initial stages of convective development Friday afternoon.
Confidence is rather high that the entire region will see
storms, with potentially numerous reports of severe weather,
but given the rapid upscale growth expected...the messy
resultant nature of the convection poses uncertainty with the
magnitude of the severe risk. If storms can maintain a discrete
nature for a sufficiently long period of time, an isolated
strong tornado could occur given the highly favorable
environment.

Flash flooding is also more of a concern on Friday, as multiple
rounds of storms may develop during the afternoon/evening,
especially if storms end up training on the south side of the
developing mesoscale convective system (favoring southern
portions of the forecast area). With recent rains across the
area, we remain rather vulnerable for instances of flooding,
particularly with small streams/creeks and in urban areas.
Precipitable water values Friday afternoon will be unseasonably
high (generally 1.3-1.6 inches), and training convection will be
possible during the evening as the low-level jet increases,
impinging on the southeastward-progressing cold front.

As the cold upper trough moves into the central Plains by
Saturday, strong cold advection upstream of the front will bring
much colder temperatures to the region by Saturday. Highs on
Saturday will be 20-30 degrees colder than Friday, with lows
Saturday night approaching the freezing mark in northern
portions of the forecast area as a strong surface high
approaches. Not out of the question we have to issue a few
frost/freeze headlines for that period.

Warmer temperatures will commence quickly, with Sunday warming a
good ten degrees with subsequent warming on Monday and Tuesday
to temperatures a good 10-15+ degrees above average. The next
chance for precipitation comes by the middle of next week, as
long-range models are showing another active period developing
for the close of April.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 619 PM CDT Wed Apr 15 2026

VFR conds are expected thru the TAF pd with sct-bkn clouds
around 8kft fcst thru 02Z-04Z aft which only a few high clouds
are expected. Winds to begin the TAF pd will be out of the south
at IXD and MKC with a frontal boundary just west of the TAF
sites. The front is nr MCI so winds may temporarily be out of
the west btn 10-15kts with gusts to 20-25kts thru 01Z-02Z
before winds back to south btn 5-10kts while winds at STJ will
be out of the west at 10-15kts with gusts to 20-25kts before
becmg lgt and vrb aft 02Z. Aft 15Z...winds will become southerly
at all TAF sites btn 7-12kts with a few gusts to 20kts poss aft
18Z.

&&

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

&&

$$

SHORT TERM...CMS
LONG TERM...CMS
AVIATION...73