St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

009
FXUS63 KEAX 120456
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
1056 PM CST Thu Dec 11 2025

.KEY MESSAGES...

- Mostly Mild Weather, Light Snow Near Kirksville Region This Evening

- Accumulating Snowfall Possible North-Central to Central Missouri
  Saturday

- Very Cold Weather End of Weekend

&&

.DISCUSSION...
Issued at 322 PM CST Thu Dec 11 2025

Deep closed-low system is over the northeast CONUS with the trough
axis extending along most of the eastern CONUS. Mid-level ridge axis
has setup over the Sierra Nevada Range, resulting in strong
northwesterly flow across the Central CONUS, with a jet streak
reaching beyond 120 kts. This flow has pushed the surface
anticyclone into the Gulf region. An embedded short-wave trough
through the northwesterly flow has allowed a broad surface cyclone
to develop across much of the Plains and toward the lower Missouri
River Valley. The convergence along this has been producing the
cloud cover across the region this afternoon. Low-level winds have
also shifted southwesterly and pushed a warm front through that
helped temperatures in the southwestern two-thirds of the CWA back
into the 40s today, with a few isolated reports of 50F. The primary
mid-level vort maxima has been moving across Iowa this afternoon,
and will push through portions of north-central Missouri and most of
north-east Missouri. Within this vicinity of the surface will be the
warm front, and current model depictions are showing some FGEN
processes from northeast of Kirksville into parts of Central
Illinois. This may produce a few tenths of an inch of snowfall for
Putnam, Schulyer, and Adair Counties through this evening. The
better forcing though will be northeast of this area. A few light
flurries may extend further southwestward of this line. This should
exit our forecast area by 10pm this this evening.

Mid-level vort max exits the area by Friday Morning, pushing the
surface cyclone southward, and the stalled boundary pushes back
southward as a cold front. This will provide cooler temperatures
across the area with highs generally in the mid to upper 30s, and
lower 30s in our far northeastern counties. A closed-low through H5
will sit between the Northern Great Lakes Region and Hudson Bay,
while ridge remains in place over the Sierra Nevada region. This
continues provide brisk northwesterly flow across most of the
Central CONUS. A surface anticyclone gets pushed southwestward out of
Canada associated with an Arctic Airmass, and will enter the
northern Plains by Friday afternoon. Surface pressure rises extend
into the lower Missouri River Valley, but winds in general remain
out of the north. Model soundings are suggesting that mid-levels
remain rather saturated, which could mean cloud cover will stick
around. A few thermal boundaries will push across the area Friday
through Sunday as this anticyclone gets steered into our region. Not
much in the way of precipitation is expected on Friday, as there
will not be much in the way lift much above the surface paving the
way for a mild winter day across the area. Attention then turns to
Saturday as another punch of cold air, along with a more notable
moisture discontinuity drops southeastward ahead of the anticyclone.
Stronger mid-level vorticity is progged to work around the backside
of the closed-low over the Northern Great Lakes Region, which will
help provide more lift just beyond the surface. This will also help
to develop an area of favorable FGEN processes between 700mb-500mb,
along with lift through a rather deep DGZ. The main axis for this
forcing is from eastern Iowa into Central Illinois again, but there
will be forcing that extends southwest into north-central Missouri,
and possibly central Missouri. As a result, accumulating snowfall is
expected for our north-central and northeast counties Saturday
afternoon into evening. The main constraint will be moisture
availability. But the strong CAA and other processes could promote
snow ratios that could exceed 15:1, especially with high
temperatures only the teens in our northeast. The last few model
runs, that forcing has move slightly southwestward, which could
place a band of 1 to 2 inches across parts of north-central Missouri
to northeast Missouri, with a sharp gradient cut-off southwest of
this line. Areas from Kirksville and east-northeastward currently
hold around a 50 to 60 percent chance for at least one inch of
snowfall amongst model guidance, with 20 to 30 percent for exceeding
two inches. The current HREF runs to do not yet go out far enough,
but the 00z run this evening should capture most of the event, and
perhaps the probability matched mean fields will be able to provide
more context on potential heavier bands in our northeast. Right now,
the southwest third of the forecast area, including the KC metro,
looks to miss out on most of the snowfall.

After this strong surface anticyclone moves through, Arctic Air
filters into the region, and will provide some of the coldest
temperatures we have seen this season. Highs in our northeast
counties may struggle to get out of the single digits, especially if
there is a fresh snowpack on the ground. Areas further southwest
including the KC metro by Sunday may only see high temperatures in
the lower 20s. Sunday morning low air temps will only be in the
single digits, and wind chill values will drop below zero. Our
northeast counties may need a cold weather advisory for Sunday
morning. After this system moves through, starting next week,
deterministic models are showing a return to southwesterly low-level
flow which could send afternoon high temperatures back into the 50s
by the middle of next week. The roller coaster of temperatures
likely continues.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1055 PM CST Thu Dec 11 2025

A brief stratus deck is now looking like it will pass through
the TAF sites around midnight through the early morning hours
Friday. This is noted on upstream observations and satellite
imagery over southwest IA/southeast NE. They should arrive at
STJ around midnight and only offset by a couple hours as the
cloud deck sags southward. Otherwise, fairly quiet flying
conditions anticipated with this issuance with winds remaining
at or below 10 kts.

&&

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

&&

$$

DISCUSSION...Krull
AVIATION...Cooley