St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

737
FXUS63 KEAX 271128
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
628 AM CDT Mon Jul 27 2026

.KEY MESSAGES...

- Extreme heat continues. Temperatures once again push 100F and
  heat index values reach 110F - 120F. Overnight conditions
  remain uncomfortable. An Extreme Heat Warning continues
  through Tuesday morning.

- Limited opportunities for precipitation (~10-20%) return this
  afternoon across central MO. Additional rounds of mainly
  overnight showers and storms possible through the rest of the
  week.

- Gradual relative cooling through the week before a more
  substantial cool down next weekend.

&&

.DISCUSSION...
Issued at 301 AM CDT Mon Jul 27 2026

Satellite imagery shows little movement in the expansive ridge over
the eastern Rockies. Same goes for the midlevel ridge across the
Gulf coast. Surface winds out of the southwest boosted by enhanced
low level flow into the region maintains a steady stream of warm air
advection. Shortwave troughs aloft have been consistently pummeling
the ridge slowly redirecting upper level flow to more northerly.
This has been advecting drier air into the area which has reduced
our dew points from near 80 to the upper 70s. Ironically, this might
increase our chances of reaching triple digits today as less energy
is required to heat up drier air compared to saturated air. Highs
today look more likely to reach triple digits with HREF ensembles
showing 70-90 percent chances of patches of 100F air temperatures
along and west of the I-29/I-49 corridors. This also results in a
zero sum of heat index values with the increase in temperatures
negating the decrease in dew points. Heat index values around 110F-
115F with areas of 120F expected. Overnight lows once again reside
in the upper 70s Monday into Tuesday.

As mentioned previously, passing shortwave troughs have been
gradually weakening the ridge`s hold on the area. Over time, this
creates more exposure to pockets of cyclonic vorticity advection
which brings the potential for isolated shower and thunderstorm
development. Guidance was proposing the first opportunity for this
early this morning; however, observations have been less favorable
for anything more than an isolated shower occurring. The next
substantial opportunity is late this afternoon as a more significant
shortwave traverses IL with the boundary extending as far west as
KC. Deterministic guidance is a little more confident in showers
coupling the previously mentioned trough across the Great Lakes. CAM
guidance is a little less optimistic about storm development, but
does paint the potential for some storms to spread as far west as
Higgensville. This may work to quickly lower heat indices later this
afternoon across central MO, but confidence remains fairly low at
this time. The good news is this passing trough does introduce some
"cooler air" into the region. Highs Tuesday reside in the low 90s
with heat indices looking to top out around 100F sans the far south
of the region where heat index values up to 105F are possible.

Looking further, the established upper level high remains planted
across the Rocky Mountains which keeps the upper level relatively
unchanged. However, shortwaves continue to transit the upper level
flow, and the eastward expanse of the upper level ridge loses a
little influence. Ridging at lower level moves eastward and opens up
the potential for some more turbulent dynamics. Extended guidance
manifests this a potential leeward midlevel troughs influenced by
the upper level shortwaves mentioned earlier. This presents multiple
opportunities for precipitation later in the forecast period, but it
would be another example of everything coming together in the right
place at the right time which adds some uncertainty. Consensus puts
most of these precipitation opportunities during the overnight
periods.

Overall, temperatures trend lower as drier and relatively cooler air
flows into the region. Highs late week look to return into the upper
80s. Passing overnight convection may work to accelerate that
cooling trend; although residual low level moisture from storms may
not make it feel much cooler. Extended guidance does show the
potential for a wholesale change in temperatures (at least for a
little bit) next weekend as a synoptic scale front is progged to
migrate through the central CONUS.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 626 AM CDT Mon Jul 27 2026

VFR conditions are expected for the duration of the forecast
period. FEW to SCT clouds are possible around 7000-10000ft.
Winds remain generally SSW around 8-10 knots.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...Extreme Heat Warning until 7 AM CDT Tuesday for MOZ001>008-
     011>017-020>025-028>033-037>040-043>046-053-054.
KS...Extreme Heat Warning until 7 AM CDT Tuesday for KSZ025-057-060-
     102>105.

&&

$$

DISCUSSION...Pesel
SHORT TERM...SPG
LONG TERM...SPG
AVIATION...Pesel