St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

674
FXUS63 KEAX 180346
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
1046 PM CDT Fri Jul 17 2026

.KEY MESSAGES...

- Scattered showers and thunderstorms continue this afternoon,
  though most areas will stay dry. Localized heavy rainfall and
  gusty winds are possible with the strongest storms.

- Heat and humidity continue for the next several days.
  Temperatures and heat indices elevate through the weekend,
  with Sunday and Monday expected to be the warmest days.

- Relief from the heat arrives for Wednesday and Thursday, with
  lesser humidity and highs in the 80s.

&&

.DISCUSSION...
Issued at 240 PM CDT Fri Jul 17 2026

Scattered thunderstorms continue to progress northeast through
portions of southeast Kansas and southwest Missouri, and are
expected to overspread the area over the next few hours. As with
yesterday, these storms will pose a risk for locally heavy
rainfall and gusty winds. That said, coverage is not expected to
be as widespread this afternoon, and this should temper the flash
flooding threat when compared to yesterday.

Any lingering storms are expected to quickly wane after sunset
with the loss of diurnal heating and instability, with dry
conditions expected overnight. The threat for additional
scattered showers and thunderstorms may persist into the weekend
as well, though confidence in this wanes somewhat. A cold front,
progged to move into northern Missouri by late Saturday evening,
looks to be the focus for at least scattered thunderstorm
development near HWY 136. Deep layer shear does increase
somewhat ahead of this boundary, but still to only ~15-20kts.
Also, forecast soundings do show dry air aloft, unlike in
previous days this week. This could allow for at least limited
updraft organization, and a threat for damaging winds appears
possible.

Attention then turns to the increasing heat as we head into the
weekend as well, with Sunday and Monday expected to be the
warmest days. Persistent warm advection aloft into Monday will
boost H85 temperatures towards the 90th percentile climo, as
high as 22-24C by Monday afternoon. This persistent warm
advection will push highs into the middle 90s by Sunday and into
the upper 90s on Monday. With dewpoints still in the lower 70s,
this will push heat index values towards 100 to 105F each
afternoon. Trends will continue to be monitored closely for
potential heat advisory issuance, especially for Monday
afternoon.

Confidence in heat concerns wanes for Tuesday, as a cold front
begins to push across the area from north to south. The
positioning of the front will drive what areas may see another
day of heat index values in the 100 to 105 range, with areas
south of HWY 50 currently under greatest risk locally. Much
drier air will be ushered into the area behind this front, with
dewpoints falling into the upper 50s in its wake. This will
bring much welcomed relief from the recent hot and humid
conditions, with lower humidity and highs in the 80s both
Wednesday and Thursday. The threat for thunderstorms looks to
return by late week, as the upper ridge reestablishes across
the southern Plains. This places the area in strengthening
northwest flow aloft. Deterministic guidance has begun to
suggest a few rounds of thunderstorms as shortwaves progress
around the apex of the upper ridge axis. All this to say,
predictability in timing and placement remains low, though the
threat for thunderstorms looks to return by late next week.

&&


.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 1044 PM CDT Fri Jul 17 2026

VFR conditions expected through the period. Scattered cumulus
are expected to develop after 17Z Saturday, decreasing towards
sunset.

&&

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

&&

$$

DISCUSSION...Brown
AVIATION...BT