St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

609
FXUS63 KEAX 031117
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
517 AM CST Wed Dec 3 2025

...Updated 12z Aviation...

.KEY MESSAGES...

- Light Wintry Mixes Today Along Cold Front

- Cold Snap Thursday

- Possible Weekend Weather System

&&

.DISCUSSION...
Issued at 413 AM CST Wed Dec 3 2025

Water vapor imagery this morning shows deep trough axis digging
toward the Four Corners Region. Strong dCVA extends into the OK/TX
panhandle region and has been developing a surface cyclone there,
prompting the surface anticyclone over our area to shift eastward
toward the Ohio River Valley. There is a deep closed low system near
Hudson Bay and an H5 ridge axis just off the coast of the Pacific
Northwest. This leaves the central CONUS with a prominent
northwesterly mid and upper-level flow regime. There is also a
strong surface anticyclone in western Canada associated with an
Arctic airmass. The surface cyclone over the OK/TX panhandle region
will attempt to move northeast along the path of CVA, and should
promote an inverted surface trough into the Ozarks Region. For areas
mainly south of Interstate 70 today, south to southwesterly flow
will attempt to provide modest WAA again. However, the strong
surface anticyclone moving southward into the Northern Plains will
prevent northward movement of the southern Plains cyclone.
Eventually, this high pressure forces a strong cold front through
Iowa by late morning and afternoon. Convergence will increase along
this front as it propagates southward. There is not much moisture to
work with, but there may be just enough to generate light wintry
mixes across portions of the forecast area late this morning through
afternoon. During the middle to late morning hours, this front will
be capable of promoting some flurry activity along the Missouri-Iowa
state line. Unsure of how long the DGZ remains saturated as this
moves through, model soundings from the RAP have been backing off on
saturation through its runs overnight. If the DGZ lacks lift and
saturation but the boundary layer is able to tap into moisture,
there is low end potential for freezing drizzle in northern
Missouri, primarily along the Iowa state line. Recent model
soundings though are showing a decreasing signal, as the depth of
saturation has become shallower, along with increasing winds with
the change in pressure gradient. Patchy ice is possible, primarily
on elevated surfaces. Not entirely confident that this will occur on
roadways, especially those roads treated for the previous snow
events. Will leave light freezing drizzle mentioned right along the
IA-MO stateline in the forecast for a traces, but no notable
accumulations expected. As the front moves southward, the HRRR and
RAP have been showing slightly better mid-level support for some
lift with an area of divergence aloft that could generate more
precipitation along the leading edge of the front. With better
saturation in the DGZ as this gets south of Hwy. 36, would expect
most of this to be snow flurries. There is a weak signal for our
southeastern counties in Central Missouri to see a few tenths of a
inch of snowfall if it can overcome the dry air. However will point
out that most short term guidance fails to produce any meaningful
QPF. Meanwhile, areas west of Hwy. 65 are not showing as much
forcing, signaling that flurry activity is most likely for western
Missouri and eastern Kansas, including the Kansas City Metro. The
cold front should pass through the area by early Thursday morning.

With the passage of the cold front and arrival of an Arctic Airmass,
temperatures will sink well below normal once again, especially for
north-central and northeast Missouri. Highs Thursday there are only
forecast to reach mid-teens. Areas southwestward will be in mostly
in the mid 20s. Thursday morning lows though will be in the single
digits for air temps. Areas south of Hwy. 50 may stay closer to the
10F-12F range. Wind chill values are forecast to drop to around 10F
below zero north of Hwy. 36. We did discuss with northern offices
about Cold Weather Advisory potential, but at this point have held
off issuing for our counties as 15F below zero may only be spotted
for an hour or two. An advisory could become necessary if there is a
stronger signal to reach 15F below zero faster, or if lasts longer
into the morning.

Friday, H5 trough digs into the southern Plains and deepens the
surface cyclone that had been suppressed by the strong high from
Wednesday into Thursday. This once again forces an inverted surface
trough back toward the Ozarks, and with the anticyclone exiting to
the east, promotes low-level southerly flow again. The WAA should
help boost temperatures back into the 30s for most of the area
(that`s still below normal for highs). Areas south of Hwy. 50 may be
able to hit the lower 40s. If the snowpack completely melts, this
may be possible. There is some mid-level forcing that ejects ahead
of this, but current guidance suggest this stays well south of
Arkansas. Therefore, keeping the forecast dry for our area. By
Saturday afternoon, deterministic guidance depicts a compact H5
trough with stronger vorticity maxima ejecting across the Central
Plains and developing a surface cyclone ahead of it. At the moment,
large degree of discrepancy between model output, with large
ensemble suite spread. Some members do not even depict this mid-
level feature moving through. This largely determines where a
baroclinic zone could potentially develop, and if we are to see
precipitation, also controls the precipitation type. Ensemble means
continue to be meager with QPF output, placing it more north and
east of the area. For now, will place some slight chance POPs from
NBM out near Hwy. 63. However, this system will need to be
monitored. Would expect model guidance to substantially change its
depiction quite a bit run to run over the next day or two for the
weekend system. The 00z GFS QPF output is currently an extreme
outlier. The official forecast reflects lower probabilities from
various ensemble suites.

Flow appears to remain fairly progressive heading into next week. We
could see the jet streak head well north of here that brings much
warmer air to the region. Ensemble spread is large. For example, box
and whiskers plots showing high temperatures where the inner-
quartile values are between 30F and 55F. A quick look at respective
deterministic solutions illustrates this, as one solution has a
strong trough in the same spot that another has a prominent ridge
axis. Extended forecast has remained largely unchanged from NBM
guidance.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 515 AM CST Wed Dec 3 2025

Cold front is moving through and will eventually lower ceilings
to MVFR, with the potential for some pockets of IFR for an hour
or two. This front may be able to produce some rain/snow wintry
mixes at times, but no substantial accumulations are expected.
This may bring visibility down for a few hours when the bulk of
the forcing is moving through. Winds eventually shift to be from
the north after the passage of the cold front.

&&

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

&&

$$

DISCUSSION...Krull
AVIATION...Krull