St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

714
FXUS63 KEAX 260451
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
1151 PM CDT Fri Sep 25 2026

.KEY MESSAGES...

- Showers expected to continue through the remainder of the
afternoon/evening. Activity remaining nonsevere, with a chance of
some rumbles of thunder.

- Brief lull in activity, before showers/storms return tomorrow
morning and again tomorrow overnight/Sunday morning.

- Temperatures remain seasonable through the forecast period. Brief
dry period to close out the weekend, before wet pattern continues.

&&

.DISCUSSION...
Issued at 317 PM CDT Fri Sep 25 2026

At the synoptic scale, broad ridging remains in place at the upper-
levels across much of the central CONUS. To the east, a closed upper-
level trough has remained mostly stationary over the East Coast,
while another upper-level trough over the PNW flanks the ridge. With
the ridge in place over the central CONUS, flow has effectively
remained blocked over the forecast area, keeping us within a
relative stagnant pattern for the past few days. However, continued
impulses within the low-level flow have served to displace us within
the periphery of the ridge. This has opened us to on-and-off
precipitation chances with enhanced synoptic ascent from greater
influence with passing shortwaves, as well as sustained warm/moist
advection from the south/southwest. This blocking will allow our
forcing and rain chances to linger until at least Sunday afternoon.

Shower activity has remained nebulous throughout the day today,
driven primarily by weak synoptic ascent from embedded shortwaves in
the atmospheric flow alongside sustained WAA in the low-levels. This
activity is expected to continue through the remainder of the day
today while warm/moist advection persists. Activity has
remained mostly isolated/scattered and subsevere in nature; this
is expected to continue being the trend with minimal
instability and poor effective shear for any organized
convection. The presence of marginal MUCAPE (~100-200 J/kg)
suggests there is low-end potential for some rumbles of thunder
through the remainder of the afternoon. However, these
probabilities remain on the lower end (~10-15%). Greater
intrusion of dry air in the low-levels looks to decrease
precipitation chances through this evening, before returning
overnight as shortwave and associated intensifying LLJ traverse
to the west/northwest of the forecast area. The greatest
potential for precipitation overnight resides across
northwestern MO and far northeastern KS (70-90%), with
isolated/scattered showers further towards central MO. Similar
to today, severe chances remain on the lower end with poor
environmental parameters for any robust activity.

As the shortwave retreats towards the north/northeast with a
diminishing LLJ, precipitation chances will lower across the
forecast area through Saturday. Surface high pressure will gradually
slide off towards the north and east as the upper-level ridge axis
is displaced by the upper-level trough lifting across the northern
CONUS. This will shift precipitation chances back over the forecast
area by late Saturday evening with the passage of another impulse in
the atmospheric flow. Severe chances continue to remain low with
meager instability and shear effectively capped off during this
timeframe, but lightning remains a risk with these storms (15-30%)
with marginally better MUCAPE than previous days.

While the upper-level trough continues to lift off towards the
north, and the closed low over the East Coast persists, ridging will
build back over the central CONUS and serve to dry conditions out
through the remainder of the weekend into early next week. The
northward and eastward progression of the ridge (and ultimate
evolution of the blocking pattern) will determine temperature trends
for Monday onward, with appreciable spread in the 25th-75th
percentile temperatures noted in probabilistic guidance. The
influence of an energetic trough over the West Coast will help to
break down the ridge going into midweek, and keep the remainder of
the forecast wetter as the jet interacts with a remnant tropical
system near southern California. This interaction with the remnant
tropical system will further enhance atmospheric moisture content,
leading to impressive PWAT values for this time of year. With these
anomalously high PWAT values, trends will need to be monitored for
the threat of flooding into next week. Temperatures will remain
seasonable through the duration of the forecast period, with high
temperatures in the 70s and low 80s during much of the period.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1148 PM CDT Fri Sep 25 2026

Shortwave building east into eastern KS is expected to lead to an
increase in shower activity across the region early Saturday
morning. A secondary wave is expected to bring additional rain
showers and/or isolated thunder to the region near 12Z along the
KS/MO border - spreading east with time. Showers are expected
to be high based resulting in VFR ceilings- except for far
northern Missouri north of highway 36 where showers are expected
to be most numerous. Shower activity is expected to decrease
from west to east later Saturday afternoon into Saturday
evening. Winds remain out of the southeast through the period.

&&

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

&&

$$

DISCUSSION...Bjork/SPG
AVIATION...IPC/BT