St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

520
FXUS63 KEAX 160738
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
238 AM CDT Wed Sep 16 2026

.KEY MESSAGES...

- Showers and embedded thunderstorms continue through the
  morning hours. More sparse coverage has overall lowered
  flooding concerns; however, isolated flooding remains possible
  from heavy downpours.

- Warmer air lifts northward through the day. Areas where it
  rains after sunrise range from the mid 70s to mid 80s while
  places south of the boundary reach the low to upper 90s with
  heat index values of 100-105F.

- The overall weather pattern from the past 2-3 days is expected
  to continue with the potential for another prolonged rain
  event over the weekend into next week. Then the pattern looks
  to become a little more progressive.

&&

.DISCUSSION...
Issued at 235 AM CDT Wed Sep 16 2026

Showers and storms look to persist through the night as shortwaves
circulating around the SE CONUS upper level high continue to pass
over the region. CAM guidance indicates a somewhat disheveled LLJ
forming across SE KS and western MO. This has resulted in slightly
lower than expected rain/storm coverage through the overnight which
tampers rain expectations slightly tampering flood concerns. With
more sparse coverage of rain, areas will see opportunities for water
to drain before the next round moves in. That said, the overall
environment remains conducive for isolated heavy downpours which may
result in localized flooding across the area.

The primary facilitator of this activity is a shallow profiled
surface cold front which moved through the area Tuesday evening. As
of midnight, the surface front sit just southeast of our CWA
stretching from approximately central IL through Jefferson City, MO
southwest through Pittsburg, KS. The midlevel front, by comparison,
resides somewhat across far SE Nebraska, NW MO, and into southern
IA. This has created an expansive area of isentropic ascent enhanced
by the passing upper level shortwaves mentioned previously. Closer
to sunrise, the boundaries are expected to retreat back northward as
a warm front keeping rain chances around, but gradually moving
northward through the morning hours. Rain should exit the region by
mid morning for those west of the I-35 corridor and early afternoon
for those east.

With the boundary moving northward, temperatures do start trending
warmer. Like Tuesday, a dichotomy of temperatures is expected with
rain cooled areas (mainly NW MO) ranging from the mid 70s to mid 80s
with low to upper 90s expected everywhere else. Who sees lower vs
high temperatures will depend on how far north the boundary makes it
through the day. Right now, the forecast calls for the boundary to
make it to the MO River Valley; however, there is a chance that the
boundary could advance further north bringing hotter air further
northward. Heat indicies south of the temperature boundary are
expected to be around 100-105F.

The upper level weather pattern continues to be dominated by a ridge
across the SE CONUS and a trough digging across the Pacific NW.
Eastern KS and much of MO find itself in the traditional ring of fire
pattern on the periphery of the expansive SE CONUS high which has
been providing at least some of the catalyst for the showers and
storms seen yesterday into this morning. Thursday, the Pacific NW
low digs a little further south which starts building a pattern of
ejecting leeward trough through the central CONUS. Combine this with
the ring of fire pattern mentioned earlier and the generally active
pattern across the region looks more likely to continue. The first
of this starts Thursday morning as a brief wave of showers and
storms looks to pass through far NW MO during the morning. As
Thursday becomes Friday, the pressure gradient across the central
CONUS contracts as the two systems battle for real estate. Lower
level dynamics look to be a bit more action packed with multiple lee
troughs taking advantage of the increased flow. There remains some
uncertainty in the track of the system as steering current from
winds aloft remain somewhat variable, but overall consensus points
to another opportunity for rain across the area Saturday through
Monday. It remains a bit far out to pinpoint fine details, but the
broad scale dynamics show another setup for a slow moving synoptic
cold front that struggles to proceed southeastward which could
present another favorable setup for prolonged rainfall. Extended
guidance shows flow opening up with systems becoming much more
transitive mid to late next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1237 AM CDT Wed Sep 16 2026

An axis of widespread showers and embedded thunderstorms has set up
across western KS and NW MO, roughly from the MO/IA state line down
to the northern KC metro. The main change since the last forecast is
that confidence has increased in KSTJ experiencing prolonged
IFR/MVFR overnight due to storms with more intermittent IFR
possible at KMKC and KMCI. KIXD should stay just south of this
axis of precipitation after 12z, and will be mainly MVFR/VFR.
Cigs will rapidly improve after storms move east of all
terminals by 15z. Winds are generally light and
westerly/southwesterly throughout the period, but expect higher
gusts around thunderstorms.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...Flood Watch until 1 PM CDT this afternoon for MOZ001>006-
     011>015-020>022-028-029-037.
KS...Flood Watch until 1 PM CDT this afternoon for KSZ025-102>105.

&&

$$

DISCUSSION...Pesel
AVIATION...Shaw