St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

519
FXUS63 KEAX 192253
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
553 PM CDT Sun Jul 19 2026

.KEY MESSAGES...

- Scattered thunderstorms will develop this afternoon into early
  tonight, mainly near and south of I-70. Some storms could
  produce torrential downpours and isolated flash flooding.

- Dangerous heat and humidity is forecast Monday into Tuesday.
  A Heat Advisory is now in effect Monday afternoon for all the
  region, and for northern sections of southwest MO and
  southeast KS on Tuesday.

- A frontal boundary will bring a chance of thunderstorms Monday
  night into Tuesday in far north and northeast MO.

- Additional chances for widespread thunderstorms return to the
  forecast Thursday into Friday, along with cooler temperatures
  and lower humidity levels.

&&

.DISCUSSION...
Issued at 1233 PM CDT Sun Jul 19 2026

Early this afternoon, convection is firing along a boundary
extending from west to east near the Missouri River. This
boundary is associated with low pressure moving across the
northeast CONUS. With PWAT values around 2.0" and an very
unstable, uncapped (but also unsheared), slow moving storms
capable of producing 1-2" per hour rainfall rates will be the
main concern through late this afternoon. Isolated pockets of
flash flooding are possible as result. The lack of shear should
preclude any severe risk, but gusty winds of 30-40 mph are
possible from any storm that collapses.

Once the storms wind down tonight, the expansive ridging across
the southwest CONUS will briefly expand back over the region
Monday into Tuesday. This will cause the frontal boundary to
retreat to the NE. With high temperatures forecast to reach the
lower to middle 90s and dew point temperatures in the lower to
middle 70s, most everywhere in the forecast area should see peak
heat index values of 105-110. Opted to expand the Heat Advisory
to the entire forecast area for Monday after collaboration with
neighboring offices.

On Tuesday, the ridge will retreat to the west again, but very
gradually. This will allow the frontal boundary to again push
into northern MO. Storms will fire along this boundary Monday
night into Tuesday morning, impacting parts of far northern and
northeast MO. SPC has this area in a Marginal Risk, but it does
appear the most favorable shear values will stay north of the
area in Iowa. Additionally, the late night timing could limit
instability. If severe storms do form, isolated damaging wind
gusts would be the main threat.

While there is still some uncertainty in how quickly the frontal
boundary will move through the forecast area Tuesday, ensemble
guidance shows this front not reaching locations south of the
Missouri River/US 50 until Tuesday evening. This will allow for
heat index values to again reach 105-110 Tuesday afternoon, so
opted to extend the Heat Advisory for these areas until 7 PM
Tuesday.

For the middle to latter half of next week, the ridging will
finally retreat well to our west, allowing the region to come
under a NW flow baroclinic zone. This will allow temperature and
humidity to cool back to more comfortable levels. Additionally,
within the northwest flow regime, MCS activity may impact the
area. Ensemble guidance is keying in on two periods, late
Wednesday night into Thursday morning and again Thursday evening
into Friday morning. Depending on how organized these storm
complexes are, we will need to watch for the potential of severe
thunderstorms.

One last note on the forecast, model guidance is showing the
shift to NW flow flow aloft will allow plentiful amounts of
high-level wildfire smoke to move into the area beginning
Tuesday. At this time, the smoke looks to stay suspended well
above the ground, but skies will become noticeably hazy

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 549 PM CDT Sun Jul 19 2026

Isolated storms around the KC metro and east of highway 65 are
expected to disscipate towards sunset.  Southeast winds should prevail
through the overnight, becoming more southerly throughout the day
tomorrow. Expecte few to scattered cumulus to develop along and
south of I-70 tomorrow, most numerous south but too capped for any
thunderstorm potential.
&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...Heat Advisory from 1 PM to 9 PM CDT Monday for MOZ001>008-
     011>017-020>025-028>033-037>039.
     Heat Advisory from 1 PM Monday to 7 PM CDT Tuesday for MOZ040-
     043>046-053-054.
KS...Heat Advisory from 1 PM to 9 PM CDT Monday for KSZ025-102>105.
     Heat Advisory from 1 PM Monday to 7 PM CDT Tuesday for KSZ057-
     060.

&&

$$

DISCUSSION...Snyder
AVIATION...BT