St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

511
FXUS63 KEAX 162313
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
613 PM CDT Sun Aug 16 2026

.KEY MESSAGES...

- Scattered showers and storms possible this afternoon (30-50%
  chance).
- Severe weather not expected across northern MO.
- Strong to severe storms possible across central MO.

- Some relief from the heat is expected heading into the
  upcoming week

- Additional rain and storm chances arrive Tuesday into
  Wednesday.

&&

.DISCUSSION...
Issued at 127 PM CDT Sun Aug 16 2026

The 500-hPa ridge that has been persistent over much of the
CONUS for the last week or so has finally begun to flatten out
and break down as a trough builds in over Canada. Several
shortwaves can still be noted moving through the flow, with the
most impactful one for northern MO being located over IA and
northern MO. This shortwave is associated with a remnant MCV
from convection across NE/KS/IA/MO last night and early this
morning. At the surface, multiple boundaries are analyzed across
the Missouri River Valley. A stationary front was augmented by
convection this morning and has moved south as more of an
outflow boundary than a front. It is currently located across
central MO and is characterized by cooler temperatures to its
north (low-to-mid 80s), but dew points remain in the low-to-mid
70s behind it. There is also a cold front that is slowly moving
southeast through NE and IA. This front will move across
northern MO tonight and will knock dew points into the mid-60s
and will bring an end to the muggy feel that has become normal
over the past week or so.

With the remnant MCV moving across northern MO this afternoon,
there is ample upper-level support for convection, however,
showers and storms moved over this same area this morning and
cloud cover remains present, so it will take a bit of recovery
to create a favorable environment for storms to blossom.
Mesoanalysis shows up to 1000 J/kg of MUCAPE along and north of
the Missouri River, but 100-200 J/kg of CIN are inhibiting
storms from forming. Current expectation is for a few showers
and maybe a rumble of thunder or two along and north of the
Missouri River this afternoon (30-50% chance), however, severe
weather is not expected. The only way for a stronger storm to
be possible would be for clouds to clear out and some
destabilization to occur relatively soon, which seems unlikely
at this point in the day (230 PM CDT).

A better parameter space for storms exists south of the
periphery of the cloud cover across central MO (roughly along
and south of the Missouri River). Across this area, 2000-3000
J/kg of MUCAPE is present, however, a lack of forcing is
limiting the convective potential. Storms may be able to form
along the outflow boundary late this afternoon and evening,
however, this would largely be south of the CWA.

Clearing skies are expected late tonight across northwestern MO
behind the cold front, which paired with light winds, will
create a setup that is favorable for fog formation. As such,
have added some patchy fog to the forecast for areas along and
north of US-36 and west of I-35 through the early morning hours.

Monday will see much less oppressive conditions than last week
with highs in the mid-80s and dew points in the mid-60s behind
the cold front. Precipitation chances remain near zero through
the day as well. However, the quiet weather will not last long
as the next shortwave is progged to move across the Northern
and Central Plains Tuesday into Wednesday. Storms are expected
to initiate north of the area Tuesday afternoon/evening ahead of
an advancing cold front in an environment characterized by
moderate to strong instability (2000-3000 J/kg of MLCAPE) and
ample deep layer shear (30-40 kts). It seems reasonable that
initially discrete cells may grow upscale into a multicell
cluster or MCS along the cold front as the LLJ increases through
the evening. Storms would then reach northern MO late in the
late or perhaps overnight. This timing throws a good deal of
uncertainty into the forecast regarding the severe potential
across northern MO, however, the primary risks seem to be strong
to damaging winds and heavy rainfall. SPC has areas along and
north of US-36 outlined in a Day 3 Slight Risk (Level 2 of 5)
for severe weather with a Marginal Risk extending to the I-70
corridor. A Slight Risk for excessive rainfall has also been
issued for much of northern MO over this same time period.

Model guidance depicts a northwest flow regime setting up
through the remainder of the forecast period with several
shortwaves moving through the flow. This indicates a rather
active stretch of weather may be in store through the next week
or so, although many of the finer details (capping, timing,
moisture, etc) have yet to be resolved, so this is a trend that
will require monitoring over future forecast cycles.

&&


.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 613 PM CDT Sun Aug 16 2026

Expect sct-bkn cu around 5-6kft to persist thru 02Z aft which a
few-sct high clouds will prevail thru 16Z. This may lead to
some lgt fog development between 10Z-14Z which is fcst to reduce
vis to 4SM-5SM (and may temporarily reduce vis to 1/4SM at STJ).
However, fog should burn of by 14Z with just sct cu around 5kft
expected durg the day tomorrow. Winds will be out of the N/NNW
thru the TAF pd around 5kts.

&&

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

&&

$$

DISCUSSION...Carothers
SHORT TERM...
LONG TERM...
AVIATION...73