St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

233
FXUS63 KEAX 221151
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
551 AM CST Sun Dec 22 2024

.KEY MESSAGES...

- Warming trend begins today. Temperatures reach into the 50s next
week.

- Overcast and soggy Christmas Eve through weekend anticipated.

&&

.DISCUSSION...
Issued at 343 AM CST Sun Dec 22 2024

Satellite shows a quiet sky above eastern KS and western MO tonight
thanks in part to midlevel ridging across the Central Plains. This
has allowed nocturnal temperatures to sink a little more than
anticipated; however, warm air advection from the south has
mitigated temperatures from falling too far. Satellite imagery also
shows a leeward trough deepening across the Northern Plains which
drops a cold front across the central Plains. The pressure gradient
tightens ahead of the front bringing some gusty winds through the
afternoon. Wind gusts around 20-25 MPH with some isolated 30 MPH
gusts are possible. This flow quickly elevates temperature above
normal with 40s and 50s sticking around through the end of the week.
The front progresses through overnight Sunday into early Monday
morning. Notable moisture transport ahead of the front, low level
saturation, and weak isentropic ascent show the potential for some
fog and drizzle; however, low level winds may be a bit strong and
overall weak forcing keeps precipitation chances minimal.

Confidence is increasing in the potential for rainfall around
Christmas and the days following. Guidance has been consistent in
pushing a longwave trough across the Rockies Monday evening into
Tuesday. The wave introduces CVA across a substantial area of PV
with lower level PV maximums across western OK. This encourages the
development of a leeward cyclone early Christmas Eve. Frontogenesis
occurs fairly quickly with warm frontogenesis expected somewhere
between the US-36 and I-70 corridors. Mostly light rain is expected
as QPF struggles to reach 0.25 inches; however, moisture transport
ahead of this wave pushes PWAT values around 0.5 to 1 inch
suggesting a potential for some heavier showers. Timing of heaviest
rainfall looks to be during the morning daylight hours; however,
rain chances looks to linger through most of the day exiting just in
time for Santa`s overnight flight.

Backside ridging keeps Christmas day dry however, those who
wished for clouds for Christmas look to get them. A few peaks at
the sun are possible, but it is mainly looking cloudy and
gray as the next system approaches for Dec 26th. Models
prog a deeper trough across the western CONUS digging into the
Southern Plains. This particular model suite has been more
aggressive than previous runs showing a deep tap into Gulf
warmth and moisture advecting into IA by end of day. The
instability/CAPE signal is more pronounced showing increased
potential for thunderstorms Thursday afternoon/evening. Several
uncertainties need to be resolved, but preliminary analysis
suggests a potential for some thunderstorms which given the
season could produce some small hail and gusty winds. Higher
resolution analysis in the coming days will paint a more clear
picture of storm potential.

Where confidence is high is the active pattern continuing through
the remainder of the year. Hemispheric plots continue to show the
ejection of shortwaves across the CONUS from the Aleutian Low and
Pacific High yielding multiple waves which could potentially bring
precipitation to our area. There remains a lot of uncertainty as
each model iteration moves precipitation around substantially.
Observations compared to model trends show more consolidated upper
level shortwaves compared to model projections. While that
consolidation is being reflected run to run in the models, it seems
to be limited to the first 4-5 day window before they start
proliferating shortwaves. That said, confidence remains high in the
active pattern continuing into 2025.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 550 AM CST Sun Dec 22 2024

Breezy VFR conditions are expected for a majority of the
forecast period.

Mainly SKC through the morning. Tightening pressure gradient
and downward mixing create gusty southerly winds after sunrise
with peak gusts this afternoon around 20-25 knots; some isolated
higher gusts are possible. While gusts dissipate around sunset,
winds maintain around 10-12 knots through the night becoming
more southwesterly.

High clouds build in through Sunday afternoon ahead of a cold
front expected during overnight. CIGs gradually lower ahead of
the front`s arrival with MVFR CIGs anticipated through the
second half of the overnight expanding in coverage through
sunrise Monday.

&&

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

&&

$$

DISCUSSION...Pesel
AVIATION...Pesel