St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

389
FXUS63 KEAX 270858
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
358 AM CDT Mon Apr 27 2026

.KEY MESSAGES...

- Severe thunderstorms will persist through the morning across
eastern KS and western MO, with some impact on later storm
development further west.

- Strong/severe storms anticipated to develop further east  during
the afternoon and into the evening, with all severe  hazards
possible.

- Mostly quiet forecast period ahead, with some isolated chances (20-
40%) for showers/storms through the period.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 345 AM CDT Mon Apr 27 2026

Continued convective activity is expected through the overnight
hours into the morning today. From a mesoanalysis perspective,
elevated storm modes have been able to persist through the night
with adequate MLCAPE values (around 1000-1500 J/kg) and ample
environmental shear (50-60 kts) along the left exit region of the
LLJ. An elevated dry layer persists to the southeast of the main
line, with upscale growth occurring more towards the northeast
through time. These storms have a history of producing large hail
and damaging winds further west, which will continue to be the
concern through the overnight period. Current CAM guidance shows
this cluster of storms congealing into a line that will push towards
the southeast during the early morning hours, with consistency
between subsequent iterations of the HRRR through the night and
reflected by the 6z run of the RAP. However, continued mesoanalysis
will be the greater influence on subsequent updates to the forecast
as the event progresses. With this line of storms, there is concern
for flash flooding along a line through the KC Metro. Present PWAT
values over our immediate forecast area reside around 1-1.5 inches,
but our threshold for meeting flash flood guidance for hourly
precipitation is around 1.5 inches, which will easily be
met/exceeded in convective storms. Thus, will be continuing to
monitor the potential for flooding/flash flooding tonight and into
this morning, especially for areas where training precipitation
could occur over the next few hours.

Regarding the remainder of the day today, any lingering shower/storm
activity should gradually exit the area through the afternoon as the
cold front begins to push in with a deepening surface cyclone
lifting from the OK Panhandle towards the northeast. There is some
uncertainty on how current weather will impact storms developing
further west, as current storms would aid in further stabilizing the
atmosphere. Greater confidence in severe activity exists further
towards the east around Kirksville/Macon area, with greater
instability generation during the day and more significant synoptic
forcing along an eroding capping inversion. With any storms that
initiate along the cold frontal boundary, the threat for all severe
hazards exists, with moderate mid- level lapse rates on the order of
7.5-8 degC/km and effective shear around 50-60 kts supporting
organized storm development. Some CAMs try to force activity behind
the passing cold front, but the threat of these storms scaling
upward into severe storms remains lower, as the cold front will
effectively wipe out any favorable storm environment as it passes
through.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 345 AM CDT Mon Apr 27 2026

The upper level trough north of the Great Lakes will generate
shortwaves that will invigorate some chance of precipitation through
the remainder of this week, with the chance (30-50%) for
showers/storms south of the US-50 corridor Tuesday
afternoon/evening. Otherwise, weather will remain generally quiet as
we reside under northwest flow with the upper level trough digging
towards the Great Lakes through the period. There is some chance for
additional precipitation chances (10-30%) late Thursday/early
Friday, but general model deviance at this point does not place high
confidence in this outcome. Highs will remain much cooler than in
previous days, with highs forecasted in the low-mid 60s through much
of the forecast period before warming back up near the end of the
forecast period.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1230 AM CDT Mon Apr 27 2026

Earlier weather has moved out of terminals, but redevelopment to
the west will place terminals under prevailing thunder starting
at 7z through the early morning. Expecting impacts to
visibility and cloud ceilings with storms to MVFR, but could see
visibilities drop to IFR with strongest storms. By 11Z, not
enough confidence in the persistence of thunder at terminals to
warrant a prevailing condition, so placed a PROB30 group to
account for potential of lingering showers/rain through 13z. By
roughly 15-18z, expecting winds to pick up with gusts up to
20-25 kts expected through the afternoon. Cold frontal passage
will shift winds out of the northwest to end the forecast
period, with ceilings gradually clearing out behind the front.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...Flood Watch through this evening for MOZ001>008-011>017-
     020>025-028>033-037>040-043>046-053-054.
KS...Flood Watch through this evening for KSZ025-057-060-102>105.

&&

$$

SHORT TERM...SPG
LONG TERM...SPG
AVIATION...SPG