St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

552
FXUS63 KEAX 240602
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
102 AM CDT Fri Jul 24 2026

.KEY MESSAGES...

- Expansive rain expected Thursday night continuing through
  Friday becoming more scattered during the evening. Localized
  heavy rainfall is possible which may result in flooding.

- Heat and humidity return this weekend through much of next
  week. Heat index values of 105-110 anticipated Saturday (south
  of the MO River) and Sunday (area wide).

- More hazardous heat is possible throughout next week; however,
  potential convective activity may tamper with heat
  expectations.

&&

.DISCUSSION...
Issued at 101 AM CDT Fri Jul 24 2026

A heavily moisture ladened air mass dominates the region with CAM
analysis showing PWAT values around 2 inches across the Kansas and
western Missouri River Valleys. A complex of showers and
thunderstorms across central KS are expected to continue moving
eastward toward the region through the overnight. The 850mb LLJ is
forecasted to expand northward through the overnight accelerating
southerly flow across the low level. This combined with isentropic
ascent across the meso warm sector and a passing upper level
shortwave results in precipitation expanding northward through the
overnight enveloping much of the western portions of the coverage
area by sunrise. Meso-analystics continue to show a less than
favorable convective environment across a geographic scale with
limited instability, lowering bulk shear, and minimized lapse rates;
however, model vertical profiles paint a slightly different picture.
Most model soundings show a vertical plot of temperature and dew
point, in that the lines are more or less vertical. This is likely a
result of consistent warm air (and moisture) advection into the
region negating the low level effects of nocturnal cooling. However,
there is also a combination of enough warm air and moisture
advection across several layers of the atmosphere while also not
being enough to create either surface instability or upper level
capping. This creates a profile with limited CAPE and ambient
vertical motion. However, this also presents an environment that is
capable of being manipulated by relatively small factors. Rain
cooled air aloft, an enhanced area of warm air below, for example
could alter the profile enough to keep convective storms going or
dissipate them. Consensus leans towards CVA from the upper level
wave tapping into the saturated vertical column creating just enough
lift to generate some showers and isolated thunderstorms. The
primary uncertainty will be how the approaching thunderstorms
complex to the west will manifest the environment. Likely we will
see a mixed combination of scattered showers and more robust
thunderstorms. It is not likely that storms will alter the ambient
environment significantly enough to create deep convection or
manifest severe hail or damaging winds, but with the high PWATs
mentioned earlier, heavy rainfall remains the primary concern.

Rain moves in before sunrise Friday and sticks around through much
of the daytime hours. Once rain moves out Friday night, ridging
begins to dominate the weather pattern once again bringing the
potential for dangerous heat and humidity across the region.
Ensemble guidance for Saturday shows a 60-80 percent chance of 105F+
heat indices south of the MO River. This is likely due in part to
resident saturation from Friday`s rainfall; so therein lies some
uncertainty in peak heat potential as precipitation could affect the
temperature outlook. Sunday, the heat expands with 50-60 percent
chances of 105F+ across the area and 30-40 percent chances of
exceeding 110F. Looking into Monday and beyond becomes a little more
uncertain as long range guidance favors centering the ridge over the
eastern Rockies which put our region right in the path of ridge
running overnight thunderstorm complexes which are notorious for
messing with hazardous heat expectations. If storms do pass over,
rain and residual cloud cover could taper heat; however, if not,
hazardous heat becomes much more likely.


&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1206 AM CDT Fri Jul 24 2026

An area of thunderstorms is moving into eastern KS currently and
timing this area into the terminals puts its arrival around
08Z. Have moved up the timing an hour to account for this and
also added some thunderstorm mention with a two hour TEMPO
group. Thunderstorm chances decrease after the initial area
moves through so have transitioned to SHRA mention after 10Z.
SHRA activity persists through the morning with precipitation
moving east by the afternoon. Conditions will trend from VFR
early in the forecast to IFR by tomorrow afternoon, with MVFR
conditions likely during the morning.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...Extreme Heat Watch from Saturday afternoon through Tuesday
     evening for MOZ001>008-011>017-020>025-028>033-037>040-
     043>046-053-054.
KS...Extreme Heat Watch from Saturday afternoon through Tuesday
     evening for KSZ025-057-060-102>105.

&&

$$

DISCUSSION...Pesel
SHORT TERM...Camden
LONG TERM...Camden
AVIATION...CDB