St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

466
FXUS63 KEAX 021708
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
1208 PM CDT Sat May 2 2026

...18z Aviation Update...

.KEY MESSAGES...

- Frost advisory this morning north of the Missouri River

- More active patter returns Sunday evening with periodic chances of
thunderstorms, some of which could produce large hail or damaging
winds.

&&

.DISCUSSION...
Issued at 322 AM CDT Sat May 2 2026

Temperatures have not fallen off as much as expected overnight due
to a few mid level clouds hanging around southern Iowa into north
central and northeast Missouri.  These clouds are expected to clear
shortly, allowing areas under the frost area to fall into the 30s.
As such, will be keeping the frost advisory as is, though conditions
may be marginal.

Surface high pressure centered over central Nebraska as of 08Z will
slowly shift southeast leading to light northwest winds across the
region today. High temperatures will fall short about five degrees
below seasonal norms.

As surface ridge pushes east this evening, winds will increase out
of the south-southwest.  Moisture return will be limited however, as
winds down near the Gulf will remain out of the north through
Sunday.  With the southwest flow, will see a nice rebound in
temperatures on Sunday into the upper 70s to even lower 80s.
Temperatures will be a bit cooler across northern Missouri as a
slowing cold front builds south into the region.  Airmass ahead of
the front is unstable with 1000-1500 J/kg of surface based CAPE.
Models suggest a cap through much of the day, but it is forecast to
weaken late in the day as a series of shortwaves pass through in
zonal flow.  Both NAM NEST and ECMWF suggest the potential for
scattered thunderstorms developing along the cold front which may be
located near I-70 Sunday evening. NAM NEST moves through storms east
along the front close to the mean wind, while the ECMWF lifts the
storms northeast in time.  Not sure there is enough anti-cyclonic
curvature in the hodographs to support left moving supercells Sunday
evening, but if there was, confidence in severe hail would increase.

A second cold front is expected to build south across the region
Monday evening creating another chance for late day thunderstorms.
The set up is similar to Sunday with ~ 1500 J/kg of CAPE and 0-6 km
bulk shear values of 30-35 knots.

This boundary is expected to stall in the vicinity of I-44 with
additional short waves training across the region through Thursday
leading to periodic chances of showers and thunderstorms.  After
Monday night, it appears as though central into northern Missouri is
on the cooler side of the boundary limiting instability and the
chance for severe weather.  With that said, lapse rates in the 700-
500 mb layer are still semi steep (7-7.5 deg C/km) supporting the
potential for thunderstorms (though likely non-severe).

Warmer conditions develop late week as upper ridge across the
western US expands east.  Deterministic models still suggest the
potential for shortwaves dropping southeast (most pronounced in the
ECMWF and Canadian) creating the potential for additional storms
late week, but not a lot of consistency amongst the models so for
now the NBM has maintained a dry forecast.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1206 PM CDT Sat May 2 2026

VFR conditions expected to prevail across the sites through the
period. Winds will gradually shift through the period, initially
from the NW turning W to SW to SSW overnight. Winds settle out
of the SW/SSW with increasing sustained and wind gusts during
latter portions of the period. Gusts into the mid 20s kts likely
common late in the period.

&&

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

&&

$$

DISCUSSION...BT
AVIATION...Curtis