St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

561
FXUS63 KEAX 301933
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
233 PM CDT Fri Oct 30 2026

.KEY MESSAGES...

- Scattered to widespread showers (50-80% chance) this evening
  and into Saturday. A few lightning strikes are possible this
  evening (10-20% chance).

- Isolated showers possible (15-30% chance) Saturday afternoon
  and evening.

- Showers and thunderstorms are likely (60-95%) Monday and
  Tuesday. Some storms on Monday could be strong/severe, but
  uncertainty remains.

&&

.DISCUSSION...
Issued at 232 PM CDT Fri Oct 30 2026

Comparison of 00Z and 12Z upper-air observations detail a deepening
upper-level trough over the Pacific Northwest and continued broad
ridging/near-zonal flow more centrally located over the CONUS.
Mid/low-level flow has become increasingly southerly/southwesterly
overnight and into the morning, advecting moisture into the region.
A mid-level shortwave mapped over southwest Texas is set to propel
northeastward into the the Central Plains later today. A surface
boundary that moved through the area yesterday now rests over
central Missouri but is expected to lift north today as a warm
front, bringing with it renewed rain and storm chances. Over the
course of the afternoon, the expectation is for elevated instability
to rise to around 500 J/kg. Based on forecast soundings, however,
this layer of instability is rather shallow. There may be a few
cells capable of producing some lightning, but current thinking is
that most will remain as light rain showers. Rain chances will
increase to about 40-50% south of the Missouri River by 6 PM or so
before expanding further north overnight. Confidence in rain is
greatest primarily in areas west of I-35 where hourly PoPs approach
70-80% just around midnight. WPC has maintained a Marginal Risk
(Level 1 of 4) for excessive rainfall for portions of northern
Missouri and northeastern Kansas. PWATs range from about 1.25"
across northern Missouri to 1.5" further south as well as closer to
the MO/KS border and Kansas City metro. 15-mile neighborhood
probabilities for 24-hour rainfall accumulations of at least 0.25"
by 1 PM Saturday are lowest (~15%) in central Missouri and increase
further to the northwest. The highest probability corridor sits
roughly between I-29 and I-35 in Missouri (including the Kansas City
metro) where neighborhood probabilities begin to exceed 80% for at
least 0.25" of rain. Model spread is also higher in these areas
(generally a 0.25-0.5" difference between the 25th and 75th
percentiles). All that said...generally expecting around 0.25" to
0.5" of rain west of I-35 through early Saturday afternoon.
Elsewhere, accumulations will likely fall below 0.25". Locally
higher amounts will be possible, but these values should provide a
broad overview of expectations.

Isolated to scattered showers will continue Saturday afternoon and
potentially into the evening. The mid-level trough is anticipated to
move out of the area by early/mid afternoon, and much of the support
for continued precipitation will fade along with it as low-level
flow becomes more easterly, drying out the 1000-800mb layer. As
such, guidance reduces rain coverage during the late afternoon and
early evening hours for most portions of our area. Some uncertainty
is introduced by a weaker shortwave that approaches southeast Kansas
and southwest Missouri as it could help spawn some showers in the
evening. Given the low-level dry layer, though, these would be
isolated and brief in nature. Nonetheless, retained the 15-30%
chance for an isolated shower in the evening/overnight period.
Sunday looks dry with temperatures in the upper 60s and low 70s
across the forecast area.

Rain chances return late Sunday night and into Monday as an upper-
trough encourages surface cyclogenesis off of the Rockies. This
system will invite a few more days of active weather to the region
with widespread showers and thunderstorms Monday through Tuesday.
Strong (50-60 kt) south/southwesterly low-level flow is anticipated
to enshroud the Plains late Sunday night, continuing through Tuesday
morning. This will advect substantial moisture into the region with
PWATs soaring to around 1.75". This is comfortably above the 90th
percentile of KTOP`s sounding climatology. Moreover, the daily
maximum PWATs from their climatology during the first week of
November is around 1.5". Forecast PWATs are also nearing or
exceeding the maximum of NAEFS climatology. While the shear space
seems impressive, instability is certainly lesser. It`s possible
that a high-CAPE, low-shear environment awaits us on Monday ahead of
a cold front. This will be the key timeframe to monitor over the
coming forecast cycles.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1211 PM CDT Fri Oct 30 2026

Prevailing VFR conditions through the TAF period. Showers are
expected to move in from the south later this evening,
potentially preceded by isolated thunderstorms. Have included
PROB30 for -TSRA for a few hours earlier in the evening at all
four TAF sites. -RA/-SHRA expected to continue overnight,
eventually clearing in the morning. Light easterly/southeasterly
surface winds.

&&

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

&&

$$

DISCUSSION...Macko
AVIATION...Macko