St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

093
FXUS63 KEAX 161146
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
646 AM CDT Sun Aug 16 2026

.KEY MESSAGES...

- Showers and thunderstorms expected this morning. The best
  chances for storms (50-70%) are north of the Missouri River
  and in the vicinity of the US-36 corridor. Heavy rainfall and
  downburst winds are the primary hazards.

- Isolated showers and storms possible this afternoon (15-30%
  chance).

- Some relief from the heat is expected heading into the
  upcoming week, with additional rain and storm chances next
  arriving Tuesday.

&&

.DISCUSSION...
Issued at 1204 AM CDT Sun Aug 16 2026

The latest upper-air observations showcase the weakening of the
broad upper-level ridge that has dictated much of the region`s
weather as of late. As this ridge slides toward the Eastern
Seaboard, it is projected to continue weakening with zonal upper-
level flow being established in its wake. A vortmax near the
Manitoba/Ontario border leads a cyclone between the Northwest
Territories and Nunavut that is expected to deepen over the coming
days.

Further south and closer to home, a stationary boundary lingers
across northern Missouri, extending southwestward into south-central
Kansas. A shortwave trough helped kick off convection in
southwestern and west-central Kansas earlier Saturday evening. CAMs
have struggled to determine whether or not additional initiation
will occur in the vicinity of the boundary in northeast Kansas and
northern Missouri during the overnight hours. It does appear that
initiation would once again be largely driven by the low-level jet.
However, in comparison to previous nights, less intensification of
the low-level jet is expected, peaking at around 25 kts. Some
updrafts have developed along the I-70 corridor in west-central
Kansas, perhaps on the nose of a weak low-level jet in the vicinity
of the stationary boundary. In addition to northern Missouri, this
will be an area to watch heading into the overnight. MLCAPE across
the region is roughly between 1000-1500 J/kg, but this is
accompanied by only 20-25 kts of deep layer shear. As such, the
severe threat for any overnight convection is mainly limited to
downburst winds caused by collapsing updrafts. Heavy rainfall is
another concern, with PWATs between 2.0" and 2.2". CAMs have hinted
at training storms in the vicinity of the US-36 corridor...if this
comes to fruition, flooding may become a concern.

The aforementioned shortwave which supported convection in
southwestern and west-central Kansas is expected to move to the east-
northeast overnight. There are questions about whether associated
convection will be able to sustain itself this through the early
morning hours. Previously, CAMs wanted to bring a mature MCS into
northern Kansas and Missouri but are beginning to stray from this
solution, likely due to the poor shear locally. Current thinking is
that these areas may see some decaying remnants as opposed to a
strong complex of storms.

Cooler temperatures return to the region Sunday and Monday behind a
cold front progged to move through Sunday morning. The pace of this
front will determine how warm or "cool" certain portions of the CWA
will be. Confidence is high that maximum temperatures north of the
Missouri River will be in the low/mid 80s...it is south from here
that there is greater uncertainty. Current thinking is that the far
southern fringes of the CWA could range anywhere from the upper 80s
into the lower 90s. While certainly not as hot as it has been, these
areas may need to wait until Monday to feel the same amount of
relief when temperatures areawide are expected to sit in the 80s.
Some isolated showers and non-severe storms are possible (~15-30%
chance) during the afternoon hours.

Active weather makes a return Tuesday evening as a shortwave and
rolls through the Plains. Though there is considerable uncertainty
at this stage, a signal for ~1500 J/kg of MUCAPE and 25-30 kts of
deep layer shear suggests some potential for organized convection
ahead of the cold front. As the upper trough deepens this upcoming
week, northwesterly flow looks to enshroud the Central Plains,
potentially introducing additional rain and storm chances through
mid/late week.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 624 AM CDT Sun Aug 16 2026

An MCV had developed and moved into eastern KS this morning.
While the cluster of thunderstorms predominantly moving
northeast with the southern part moving toward KSTJ by 12z and
will continue across NE KS and portions of NW MO, showers and
isolated thunderstorm developed ahead on the outflow boundary
impacting mainly from KMCI, KMKC and KISD TAF sites. Brief heavy
rainfall can be expected with these thunderstorms IFR
conditions will continue through the thunderstorms moving out of
area by 15z. However, expect some redevelopment along the
frontal boundary this afternoon but confidence is not as high,
especially further north with TAF sites. For now have a PROB30
for KMCI, KMKC, and KIXD 21-23z and lower confidence for KSTJ to
be further southeast of location. Thus, have left the prob30
out for KSTJ. Once begin to clear generally VFR after 02z but
with the recent rainfall there may be potential for fog
development especially for KSTJ which for now have 6SM BR after
04z.

&&

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

&&

$$

DISCUSSION...Macko
SHORT TERM...
LONG TERM...
AVIATION...WFO EAX