St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

152
FXUS63 KEAX 092018
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
318 PM CDT Tue Jun 9 2026

.KEY MESSAGES...

* Heat Advisory in effect until 10 PM tonight. Heat index values up
  to 105 expected.

* Mostly dry weather tonight, though warm temperatures continue
  overnight.

* Slight Risk for severe weather Wednesday afternoon and evening.
  Large hail and damaging winds are the primary concerns, but can`t
  rule out the possibility of tornadoes.

* Enhanced Risk for severe weather Thursday afternoon and
  evening. Large hail and damaging winds are also possible
  across the area.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 317 PM CDT Tue Jun 9 2026

It is a mostly sunny, but hot and muggy day across the area, with
sfc temps in the upper 80s and dewpoints touching the lower 70s.
Some weak moisture convergence across northwestern MO has led to a
few isolated showers to develop, but other than that most of the
area will remain dry for the rest of the day. The Heat Advisory
remains in effect until 10 PM tonight.

Next precip chances arrive by tomorrow morning ahead of a strong
upper shortwave. Any shower and storms in the morning will be in
response to WAA and low-level jetting, and are expected to be
elevated. For tomorrow, the sfc pressure gradient will tighten,
leading to gusty southerly winds through the day. This will increase
our WAA, with afternoon temps warming into the upper 80s and low
90s. Fortunately, sfc dewpoints are not expected to be quite as high
as today due to slightly better mixing, so our heat indices should
remain below 100F for most areas. There was discussion with the
surrounding WFOs on a Heat Advisory for tomorrow, but the overall
consensus from collaboration was to not issue due to remaining below
criteria. Southerly wind gusts up to 30-35mph are expected
throughout tomorrow.

There is also a Slight Risk for severe weather tomorrow, with
scattered to numerous strong to severe storms are expected to
develop in an environment that features steep lapse rates and strong
instability. These storms will be capable of producing large hail
and damaging winds, though there remains a tornado risk as well. The
HREF prob of SBCAPE greater than 3000 J/kg is over 80% for majority
of the forecast area. With the LLJ overhead, effective bulk shear
will be favorable for supercells and organized severe convection
along or just ahead of a slow moving cold front boundary that
meanders across southeastern Nebraska and into northwest Missouri.
Timing for severe storms is primarily between mid to late-afternoon
through the late evening hours as the front slides into a strong
unstable environment. Based off the latest CAMs, the best forcing
overlapping the strong instability will be across northwest
Missouri, and the bulk of storm activity could remain along and
north I-70. Activity will likely diminish by 11pm-midnight as the
low levels become more stable and with the frontal boundary possibly
retreating back to the northwest for a short period of time. This
will cause our area to remain in a rather warm and humid air mass,
with the low temps Wednesday night remaining in the 70s.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 317 PM CDT Tue Jun 9 2026

===== Enhanced Risk for Severe Weather Thursday =====

Hot and humid conditions continue on Thursday in a pre-frontal,
strong WAA regime across the region. Moisture advection will
increase across the region ahead of an upper trough swinging across
the northern Plains, with an attendant sfc low ejecting across the
central Plains. LLJ response ahead of the low/cold front will lead
to increasing moisture transport, supporting sfc dewpoints to rise
into the 70s. Grand Ensemble probability of dewpoints greater than
75F is greater than 25% E/SE of I-35. Afternoon max temps will range
from the lower to mid-80s north of I-70, and upper-80s to low-90s to
the south. These temps combined with the sfc dewpoints will yield
heat indices approaching 100F across central MO. There could be
consideration for a Heat Advisory on Thursday, but cloud cover and
eventual precip/FROPA will inhibit the entire area from reaching
advisory level heat indices.

Sufficient heating through the afternoon will allow us to realize
strong destabilization, with a 70% chance or higher to exceed 2000
J/kg of SBCAPE through the afternoon east of I-35, where this area
will have the longest time to destabilize throughout the day. As the
cold front slides through the area Thursday afternoon, it will
become the focus for a line of thunderstorms to develop across the
region. These storms will move into a strong unstable environment
with favorable shear parameters to support organized severe storms.
Given the CAPE profiles on model soundings, large hail and damaging
wind gusts are the primary hazards, through can`t rule out a tornado
threat either given enough favorable low-level shear in proximity to
the sfc low to increase our sfc-1km SRH values above 200 m2/s2. As
such, SPC has kept a Slight/Enhanced Risks across the area in the D3
Outlook. The Enhanced Risk is for areas east of I-35.

The best timing for severe storm potential will be between 20-00z
Thursday afternoon, though this is dependent on the current timing
of the cold front. Any slow down of FROPA will result in a later
window for severe storms. PWATs will be near 2 inches, supporting
high rain rates. However, storms appear to be progressive enough to
limit flash flooding concerns. Though it`s worth keeping an eye on
this potential, given a large portion of the area has been slammed
by heavy rain and flooding in recent days. WPC paints a Marginal and
Slight Risk for excessive rainfall on Thursday.

FROPA is expected to occur around or shortly after 00z Thursday
evening, with a notable wind shift from a warm southerly flow to a
cooler NW component. Strong CAA will overtake the area, leading to
sfc temps to drop down into the upper 50s by Friday morning.

===== Friday and Saturday =====

Upper trough axis and vorticity shift across the Ohio Valley on
Friday, with sfc high pressure building across the Ozarks. Dry
weather is expected, with highs in the low-80s.

Sfc high pressure will slide east of the region by Saturday morning,
opening our area back up to WAA as another mid-level shortwave moves
across the region. Sfc dewpoints increase back into the 70s on
Saturday, with showers and thunderstorms possible throughout the
afternoon and possibly into the evening. There is potential for
strong instability again, DCAPE over 1000, and deep layer shear
greater than 30 kts.

===== Sunday into Early Next Week =====

A slightly drier trend is expected on Sunday as the upper wave moves
east. While there are some isolated chances into next week, the
greater confidence is in the pleasant temperatures. Highs for Sun-
Tue are mostly in the 70s, with lower dewpoints in the 50s and 60s.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1214 PM CDT Tue Jun 9 2026

Largely VFR conditions expected through the forecast period.
Could be a few storms tonight into Wednesday morning on the nose
of the low level jet in northern Missouri. With moist muggy
airmass across the area, could see fair weather cumulus develop
both this afternoon and again on Wednesday. Gusty south winds
develop on Wednesday ahead of an approaching cold front from the
northwest.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...Heat Advisory until 10 PM CDT this evening for MOZ001>008-
     011>017-020>025-028>033-037>040-043>046-053-054.
KS...Heat Advisory until 10 PM CDT this evening for KSZ025-057-060-
     102>105.

&&

$$

SHORT TERM...Padgett
LONG TERM...Padgett
AVIATION...BT