St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

917
FXUS63 KEAX 280439
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
1139 PM CDT Wed May 27 2026

.KEY MESSAGES...

- Seasonable Temperatures to Slightly Above Average This Week

- Periodic Showers/Storm Chances, No Notable Severe Threat

&&

.DISCUSSION...
Issued at 206 PM CDT Wed May 27 2026

A closed-low system is present over the Pacific Coast with another
troughing pattern over the New England Region. A modest mid-level
ridge axis is currently over the area and has resulted in a surface
high pressure over the middle Mississippi River Valley. Moisture
transport has remained in place across the region, maintaining
dewpoints in the mid to upper 60s across much of the area. With
daytime heating, a notable cumulus field has developed. So far in
the forecast area, no showers have occurred. A weak mid-level vort
maxima has moved across parts of southern Missouri that did produce
some light rain earlier today. Through the evening hours, this weak
lift will shift northward, and may eventually clip far southwestern
zones this evening.

The mid-level vort max will continue shifting northward Thursday
morning, increasing cloud cover across the region, as well as
gradually pushing shower activity further into the area, covering
about the southwestern third of the forecast area. A few rumbles of
thunder are possible, but overall flow remains weak and therefore
does not provide much in the way shear for storms to organize if
they develop. This trend continues into Friday, but Friday will
feature surface pressure falls associated with an eastward
propagation of the Pacific Coast system. This is expected to push
shower activity across the bulk of the forecast area on Friday, with
GEFS and other ensemble suites showing at least 70 percent
probabilities if not higher for measurable rainfall. Friday may
feature higher CAPE values especially in the afternoon from eastern
Kansas into Western Missouri, which will likely provide scattered
thunderstorms. The deep layer shear environment looks to remain weak
though, which limits the potential for storm activity to organize
and become severe.

Through the weekend, mid and upper-level flow remains in an omega
block pattern, though the western low will continue to send several
short-wave perturbations eastward that will present multiple
opportunities for shower activity. While plenty of moisture and
instability will be around, the stronger mid and upper-level flow
still remains progged to stay outside of the forecast area, and
therefore expectations for severe potential remain very low heading
through the weekend. Uncertainty in the forecast grows beyond the
weekend, as this will largely depend on if something can breakdown
the omega block pattern, or if this remains in place for longer than
currently progged. Forecast spread is fairly large due to
differences in how the break down of the blocking pattern
occurs.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1136 PM CDT Wed May 27 2026

Easterly winds are expected to remain through the period.
Increasing showers are expected after 16Z Thursday, though
ceilings and visibilities are largely expected to remain VFR
within shower activity. Lowest ceilings are expected across
west-central Missouri, with highest ceilings north of the
Missouri River where drier conditions will prevail.

&&

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

&&

$$

DISCUSSION...Krull
AVIATION...BT