St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

956
FXUS63 KEAX 201137
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
537 AM CST Sat Dec 20 2025

.KEY MESSAGES...

- Dry weather will persist (>90 percent chance) for the next
  seven days.

- Very warm temperatures are expected next week. Record highs
  are in jeopardy on Christmas Day.

&&

.DISCUSSION...
Issued at 207 AM CST Sat Dec 20 2025

An unusually breezy night is in progress, with a very strong
low-level jet moving overhead in tandem with a surface low
trekking quickly near the U.S./Canada border. A cold front will
surge southeastward as the low advances through Ontario this
morning, crossing our forecast area during the day. Moisture is
scarce, and large-scale lift is weak. Thus, no precipitation is
expected with the frontal passage. The front will also struggle
to cool us during the day as diurnal heating compensates, so
forecast highs remain a few degrees above average. Temperatures
will be colder tonight, though, bottoming out in the 20s across
the region. Sunday`s highs will be similar to today`s, as a
surface ridge progresses eastward and return flow sets up once
again.

This will set the stage for a very warm week across the lower
Missouri Valley, thanks to a broad, high-amplitude ridge
encompassing most of the CONUS. The ridge builds through at
least Thursday, as its axis reaches the central U.S. by then.
This amplification will be due in part to a very strong system
off the Pacific Coast, providing considerable warm/moist
advection downstream and an abundance of latent heat release
from the bouts of copious precipitation it generates in the
western U.S. for much of the week. With such a sluggish, high-
amplitude pattern, record highs are typically threatened near
and just upstream of the ridge axis. Sure enough, our forecast
highs on Thursday would break records in Kansas City and St.
Joseph (see record information below). NBM probabilities of 70+
degree highs are near/north of 50% on Christmas Day from I-70
southward and non-zero all the way to the Iowa border. That
would be 30+ degrees above seasonal averages.

What will become the main forecast question beyond the holiday
is how that Pacific Coast system translates eastward. This is
still beyond the official forecast period (since it will still
be a West Coast player through at least next weekend), but the
evolving pattern certainly portends that that system progresses
eastward across the U.S. in some manner. Even progressing into
such an amplified ridge, the strength of the attendant vorticity
maximum and synoptic forcing would suggest a vigorous system of
some sort. However, as tends to be the case this far out with
the general breakdown of the blocking pattern, models are wildly
variable with this evolution. We have several dry and warm days
to figure out if we see some meaningful precipitation locally before
the end of the calendar year.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 534 AM CST Sat Dec 20 2025

VFR will continue for the next 24 hours. LLWS early this morning
should cease as the low-level jet moves away from the region and
winds veer quickly as a cold front moves through the area this
morning. Southwest winds around 10 kt with gusts to 20 kt will
become north or northwest after frontal passage, with timing
generally 12z to 15z. Winds should begin to diminish late this
afternoon, becoming light and variable quickly after dark.

&&

.CLIMATE...
Issued at 207 AM CST Sat Dec 20 2025

Record High Temperatures:

December 25:
KMCI: 67/1922
KSTJ: 65/2019

Record High Minimum Temperatures:

December 25:
KMCI: 53/1936
KSTJ: 51/1936

&&

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

&&

$$

DISCUSSION...CMS
AVIATION...CMS
CLIMATE...CMS