St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

404
FXUS63 KEAX 121119
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
619 AM CDT Sat Sep 12 2026

.KEY MESSAGES...

- Strong to severe storms are possible today however, there is
  considerable uncertainty on timing and location.

- Numerous rounds of showers and storms, particularly for
  northern Missouri, appear possible next week, with widespread
  cumulative heavy rain possible.

- South of the heavier rain areas, well above normal
  temperatures look likely again with highs in the low to mid
  90s generally south of the Missouri River.

&&

.DISCUSSION...
Issued at 149 AM CDT Sat Sep 12 2026

This is a very complex and uncertain forecast with how today`s
convection will unfold. As of 06Z, a cluster of thunderstorms is
maintaining itself as it tracks southeast across southeastern
Nebraska. However, it will move into a poorer environment as it
tracks southeast, with weaker instability and shear. As a
result, anticipate this area to diminish/ dissipate with time
and southeastward extent. This area seems to be on the surface
front with reinforcement from the cold pool of the cluster of
storms. As that boundary moves south through the area later this
morning into the afternoon, it`s possible that additional
storms develop in its vicinity. However, looking through
forecast soundings for eastern Kansas and western Missouri,
there is considerable convective inhibition to overcome. With
minimal larger-scale forcing and weak forcing on the boundary,
it`s possible little or no activity is able to develop. Another
scenario is that, despite the surface based inhibition, there is
ample elevated instability that may provide enough for storms
to develop. Additionally, the NAM remains very robust in its
instability forecast and that may allow for storms develop
within the afternoon warmth along the boundary. With so much
uncertainty in the forecast, relied heavily on ensemble guidance
to derive PoPs for today. That generally depicts slight chance
to low chance PoPs (15- 30%) for our western to southwestern
zones this morning. Then just slight chances (15-20%) for the
afternoon and evening hours before increasing chances during the
late evening and overnight hours. Overnight, this method
depicts an area of 30-40% chances across eastern Kansas and
western Missouri. With regards to the potential for severe
storms, this is conditional on if we actually see storms,
especially during the afternoon/evening when instability is the
greatest. If storms are able to develop, deep-layer shear of
30-40 kts would support some organized storms with a damaging
wind and large hail risk.

Next week, ensemble guidance shows upper-level ridging, with well
above normal 500mb heights building over the southeastern US,
spreading into the local forecast area. Northern Missouri is likely
to be on the northern edges of this upper ridging. Additionally, it
looks like a quasi-stationary boundary sets up across northern
Missouri/ southern Iowa, unable to move further south due to the
strong ridging. This setup leads to multiple rounds of storms across
northern Missouri. Cumulatively, from Sunday through the end of next
week, widespread 2-5" rainfall looks possible from the repeated
rounds of showers and storms. South of this, temperatures will have
the potential to be well above normal, with highs in the low to mid
90s possible. With our normal temperatures now near 80 degrees,
highs will potentially be 10-15 degrees above normal from roughly
the Missouri River southward. These may be lower, if cloud cover can
intrude further south and inhibit insolation. Additionally, stronger
ridging could shift the heavier rain further north leading to warmer
temperatures than currently forecast.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 620 AM CDT Sat Sep 12 2026

Storms are pushing south of the terminals this morning, with
another 1-2 hours of shower activity before that diminishes as
well. This afternoon and evening/overnight, additional showers
and storms are possible. Have added a PROB30 group for what, at
least for now, has the most probable time frame for storms.
Confidence is not great in this timing as guidance remains very
inconsistent with how this activity will evolve. Winds look
light overall, becoming northerly later this morning.

&&

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

&&

$$

DISCUSSION...CDB
AVIATION...CDB