St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

985
FXUS63 KEAX 241914
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
214 PM CDT Wed Jun 24 2026

.KEY MESSAGES...

- Still looking like another active period setting up for
  Thursday into Friday with showers and storms. Flooding is
  possible with a low risk for severe thunderstorms. A Flood
  Watch is in effect for much of the area along and south of
  I-70 from Thursday afternoon into early Friday morning.

- Increasing heat and humidity with little to no rain chances
  (20% or less) this weekend into next week. Heat indices rise
  to 100 to 110 Sunday through Tuesday.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 213 PM CDT Wed Jun 24 2026

Will continue with the potential for isolated/widely scattered
airmass convection until sunset with continued heating and
minimal CAP ahead of a weak boundary into far SE Nebraska.
Weak deep layer shear generally less than 25 kt will limit
any organized severe weather potential. However, will have to
keep an eye on some gusty wind threat with any convection with
a DCAPE reservoir around 1000+ j/kg.

There will be another chance for showers and storms late
tonight. This will be attendant to a wave packet
sliding ESE from Montana and Wyoming in NW flow aloft.

&&

.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
Issued at 213 PM CDT Wed Jun 24 2026

The main focus continues to revolve around a potentially
active period Thursday into Friday morning, as a shortwave
interacts with a very moist airmass (PWATs 1.75 to 2 inches)
pooling in the vicinity of a frontal zone draped in or near
the area. The challenge is there continues to be considerable
spread in the CAM and deterministic guidance in latitudinal
variance of the heavy rain axis and also some timing differences.
There will be the low risk (level 1/2 of 5) for severe weather
later tomorrow afternoon into evening, particularly heading
south of I-70, which is progged to be closer to the surface
front and better instability (MUCAPE 1500-2500 j/kg) amidst
ample deep layer shear (0-6km 35-40+ kt) to foster a threat
mainly for damaging winds with precip loading in high WBZ and
PWAT airmass. A secondary threat for large hail would exist
should any supercells occur. In addition, with a ramping nocturnal
southwesterly LLJ enhancing low level hodographs we could see
the tornado potential develop in the evening, with the boundary
location critical to where this threat will exist - currently
suggested mainly just south of our cwa. Otherwise, the other
main threat will be heavy rainfall and the potential for flooding
given such high PWATs and warm cloud depths making for very efficient
rainfall producers. Given the southwesterly jet impinging on the
boundary there will be the potential for repetitive convection
further enhancing rainfall amounts and owing to a localized flash
flood threat. 12z HREF LPMM depicts this signal for very heavy
rain with pockets of 3-5"+. Always a concern to see such high PWATs
near 2". While there is still plenty of uncertainty in the
latitudinal position of the heaviest rainfall axis, enough of a
signal and potential exists to warrant the issuance of a Flood Watch
18z Thursday to 12z Friday for roughly along and south of I-70.
This is where the preponderance of the guidance signal for heavy
rain is suggested and where WPC`s highest probabilities for excessive
rainfall (25-39%) exist. It may be worth noting DProg/dt of the EFI
QPF over the past few runs also shows a northward shift more into areas
along/south of I-70.

Friday into Friday night there will still be some shower and storm
chances with any residual boundaries given the lingering very
moist airmass. Forcing aloft looks to be weaker and will likely
lead to lower chances and less potential for organization, with
the south/east portions of the area most favored.

This weekend through early next week continues to show very warm/
hot conditions enveloping the region as an upper level ridge
amplifies over the central CONUS. NBM interquartile spreads
are around 90 to the mid 90s in the 25th to 75th percentiles.
EFI is not marking this as extreme warmth, but given the prolonged
cool period we`ve had this will further accentuate the heat and
those with outdoor activities planned will want to be sure and practice
heat safety. Heat indices should peak in the upper 90s to near
105 degrees.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1154 AM CDT Wed Jun 24 2026

Challenges include the potential for a period of MVFR ceilings
and isolated shra/tsra this afternoon into early evening. This
potential looks to be greatest (albeit still 20-30%) near KSTJ
in the vicinity of a weak boundary, but can`t rule out isolated
convection elsewhere with a transitory bout of MVFR with any
thinning of cirrus debris. For now, have kept PROB30 mention
only at KSTJ 20z-23z. Higher moisture laden airmass may lead to
some stratus and lower ceilings (MVFR to perhaps IFR?), but
confidence is low with considerable spread and uncertainty in
the guidance. Thus, have largely maintained VFR conditions and
let later shifts re- evaluate and add if confidence increases.
Late tonight and Thursday morning there is some signal for at
least scattered convection, particularly near the northern sites
and have added PROB30 mention.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...Flood Watch from Thursday afternoon through Friday morning for
     MOZ028-029-037>040-043>046-053-054.
KS...Flood Watch from Thursday afternoon through Friday morning for
     KSZ057-060-103>105.

&&

$$

SHORT TERM...McClure
LONG TERM...McClure
AVIATION...McClure