St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

379
FXUS63 KEAX 231130
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
630 AM CDT Wed Sep 23 2026

.KEY MESSAGES...

-Seasonable temperatures continue through the end of the work week.

-Precipitation chances (30-50%) return Friday but with better
 chances (50-70%) through the weekend.

&&

.DISCUSSION...
Issued at 342 AM CDT Wed Sep 23 2026

Wednesday looks to be another nice fall day with highs in the 70s
across the area and air at 825mb starts to dry out leading to mostly
clear skies. Dry conditions will stick around for at least one more
day as the 500mb ridge over the south central US builds into our
area but temperatures should stay in the mid to upper 70s as clouds
build in over our area ahead of the rain in the Central Plains.

By Thursday night into Friday morning the upper-level ridge
begins to move east while the surface high over Quebec continues to
move east increasing our chances for rain. The falling heights at
500mb supports synoptic scale lift over strong southerly flow at the
surface supports moisture advection from the Gulf. However, models
keep the strong southerly flow off to our west on Friday so there is
only about a 30-50% chance that areas north of I-70 will see rain
with the best chances for rain staying NW. By Saturday, the strong
southerly flow shifts east into our CWA and the chance of rain
increases throughout the day Saturday with areas west of I-35 seeing
the best chance (60-70%) for rain and decreasing chances (15-30%)
for areas south of a line from Kirksville to Butler.

Rain chances will stick around for the weekend as an omega blocking
pattern forms at 500mb with another low digging into the Pacific NW,
a ridge over the Great Lakes, and a strong low off of the east coast
with our CWA located in the trough portion of the omega block. This
upper level setup coupled with the surface low sticking around to
our west and the surface high to our NE keeping moist air advecting
into our area we will potentially see rain sticking around through
Sunday. Models have little to no instability present in our CWA for
the weekend so there is little concern for severe weather, and
minimal chances for thunder. Models start to bring ridging back into
our area by Monday which would bring an end to the rain, however the
blocking pattern at 500mb may stick around longer than models
suggest which could keep rain around longer.

If the omega block does weaken by Monday, the 500mb ridge over the
south central US will move into our area and could bring high
temperatures back into the mid 80s with a 45-60% chance that our
southern most counties could see highs above 90 degrees.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 620 AM CDT Wed Sep 23 2026

MVFR CIGS present this morning but clouds should thin out around
15Z lifting CIGS back to VFR for the rest of the forecast period.
Could see visibility drop slightly to 5SM at STJ around sunrise
but not anticipating any fog this morning. Winds should stay
below 10KTS out of the east through the forecast period.

&&

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

&&

$$

DISCUSSION...Krull/IPC
AVIATION...IPC