St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

166
FXUS63 KEAX 161053
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
548 AM CDT Thu Jul 16 2026

.KEY MESSAGES...

- Isolated to scattered thunderstorms (25-50%) are forecast this
  afternoon and early this evening, mainly south of I-70.
  While severe weather is not expected, the storms could
  produce brief gusty winds and heavy rainfall.

- Temperature and humidity levels will continue to gradually
  climb, reaching the lower 90s today and Friday, the lower to
  middle 90s this weekend, and peaking in the middle to upper
  90s on Monday.

- Heat index values will reach the upper 90s to lower 100s today
  through this weekend, peaking around 100 to 110 degrees on Monday.

&&

.DISCUSSION...
Issued at 125 AM CDT Thu Jul 16 2026

We did get a few isolated showers this afternoon/evening, but
all convective activity ceased after sunset leaving us with
clear skies this evening. As of 10PM, temperatures are still
hovering in the mid 70s to low 80s across the area. We remain
mostly under the influence of broad ridging across the Central
US, though a cut-off Low has migrated westward, centered over
north Texas, advecting moisture back into mostly just the
southern half of Missouri for now. This is what drove shower and
storm activity mostly to our south, though a couple of showers
and storms did spill north into our far south and southeastern
counties.

As we go through today, the moisture plume from the southeast
will migrate north, bringing this moisture surge farther north
into our area. This will lead to isolated to scattered shower
and storms generally as far north as I-70, but wouldn`t be
surprised if a couple spilled north of I-70 as well. While we
will have a sufficient amount of diurnally driven instability,
very limited vertical wind shear is evident in soundings which
should inhibit organization of updrafts. This will keep storms
"garden- variety", pulsy (short-lived), and fairly week. The
primary hazard possible will be locally heavy rainfall as PWAT
values will be around 2-2.25", in excess of the 90th percentile
in sounding climatology for this time of year. This combined
with slow storm motion could lead to pockets of heavy rain
leading to isolated flash flood concerns. A secondary, lesser
potential hazard will be for locally gusty winds from collapsing
storms. Shower and storm activity should diminish fairly
quickly after sunset, similar to today for storms to our south.

Going into the weekend we see ridging build back up out of the
Deep South leading to additional moisture advection as well as
increasing surface temperatures. With this, we`ll see a bump in
heat indices over the weekend, into the 100 to 105 range. Could
potentially need a Heat Advisory for at least a portion of our
area Saturday or Sunday.

The redevelopment of the LLJ oriented north-northeast out of
Texas pushes north into western Missouri starting Friday night.
With this, we may see the return of nocturnal MCS development.
starting Friday night through the weekend. Due to much
uncertainty in where storms may develop or track, precip chances
remain low to below mentionable through the weekend.
The ECMWF continues to show this potential scenario over our
area, while the GFS keeps precipitation chances mostly to our
north and east.

Going into next week we see the cut-off Low over Texas break
down leading to the re-establishment of a prominent ridge over
the Central US. Guidance however amplifies the ridge over the
Rockies allowing northwesterly flow to push down into the
Northern Plains which could lead to some relief in temperatures,
especially toward the latter half of next week. Monday looks
like it could be our hottest day through this stretch with
actual temperatures warming into the upper 90s, near 100 degrees
in many locations. With dew points staying in the low 70s, heat
indices may get to 100-110 on Monday, likely necessitating heat
headlines if the current forecast pans out. As we go through the
week, though, temperatures trend back down due to the
increasing influence of northwesterly flow aloft. We may see
precip chances return as well later in the week due to the
active nature of northwesterly flow across the Central Plains.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 549 AM CDT Thu Jul 16 2026

Shallow fog will continue to impact STJ through 13z before
diminishing. This afternoon (mainly between 19-01z) isolated to
widely scattered thunderstorms will develop south of the Missouri
River and move north, possibly impacting IXD, MKC, and MCI this
afternoon and early evening before diminishing with the loss of
daytime heating.

Storm coverage still looks sparse enough to prevent more than a
PROB30 mention at this time, but that could chance with the next TAF
package. Cloud bases will be SCT-BKN between 2500-5000ft through
evening before scattering and lifting. Winds will be light from the
S to SSW around 3-6 kts.

&&

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

&&

$$

DISCUSSION...McCoy/Snyder
AVIATION...Snyder