149
FXUS63 KTOP 252043 CCA
AFDTOP

Area Forecast Discussion...CORRECTED
National Weather Service Topeka KS
243 PM CST Tue Nov 25 2025

.KEY MESSAGES...

- Thanksgiving is looking cool and dry with mostly sunny skies and
  highs in the 40s.

- Rain is likely (50-80% chance) by Saturday morning. Some light
  is forecast to develop through Saturday afternoon.

- There is a 20-50% chance for some light snow accumulations
  Saturday afternoon and evening.

- Very cold air is expected for Sunday and Monday with temperatures
  remaining below freezing and wind chills in the single digits and
  teens for much of that time.

&&

.DISCUSSION...
Issued at 155 PM CST Tue Nov 25 2025

20Z water vapor imagery showed a low pressure system over the
northern plains moving into the Upper Midwest and another wave off
the coast of the Alaskan panhandle. Surface obs had a low over
southern MN with a trailing cold front across western MO and
southeast KS.

The short term forecast is for windy but dry conditions to prevail
through tonight. Models keep a strong enough pressure gradient at
the surface for winds to remain gusty through the evening and
perhaps into Wednesday morning. But the low pressure system to the
north should not have an impact to our weather other than the windy
conditions. I would not be surprised based on the RAP and HRRR progs
if a few locations near the NEB state line flirt with wind advisory
criteria with gusts near 40 mph. But these magnitude of wind gusts
look to be so short lived that a wind advisory wouldn`t make a lot
of sense.

Models are in pretty good agreement in some mid level frontogenesis
developing Wednesday night with good saturation for some light
precip. Forecast soundings show good vertical motion through the mid
clouds, but forecast some very dry air below 800MB or about the
lowest 5 KFT. So the question is does the forcing and saturation win
out over the low level dry air? The GFS is the only solution
developing QPF and the CAMs are hard pressed to show much
reflectivity. Decided to hold off on adding a mention of precip to
the forecast thinking if it does develop, it should be so light as
to not provide much of an impact. Though if it does reach the
ground, wetbulb cooling would argue for flurries or light snow
passing through central KS Wednesday evening. Later shifts can take
another look at this.

The weather for Thanksgiving looks quiet if not on the cool side.
Mostly sunny skies may help make it feel a little warmer, but
surface ridging and light winds are expected to keep highs in the
lower to middle 40s.

The big weather maker is anticipated to impact the forecast area
Friday night and through the day Saturday. 12Z guidance is in
reasonable agreement of an open shortwave passing through the
central U.S. bringing a strong cold front through the area Saturday
afternoon. Good moisture advection ahead of the front and the
forcing from the wave is expected to cause precipitation (50 to 80
percent chance) initially in the form of rain to develop late Friday
night. As the cold front passes and temps begin to fall, the rain
may change over to light snow Saturday afternoon and evening. This
is supported by the 00Z ensembles and the NBM seems to handle the
situation pretty well. The expectation is for some minor if any
accumulations mainly on grassy surfaces. Since the dynamics are
mainly frontal driven, the opportunity for sustained snowfall is
limited by the dry air moving in behind the front. The operational
GFS seems to be on outlier with it`s QPF prog Saturday afternoon. It
appears as though it is trying to form a mesoscale band of precip.
But it is difficult to see how moisture could wrap around to the
cold side of the front while the warm conveyor belt remains out
ahead of the front. The NBM mean QPF forecast seems reasonable with
amounts generally a tenth of an inch or less as the cold air moves
in. And the probability for measurable snowfall (i.e. greater than
0.1 inch) is in the 20 to 50 percent range. Probabilities for an
inch or more fall to 25 percent or less.

Behind the front a Canadian high is progged to build in to the
central plains through Monday. This is expected to bring sub
freezing temperatures to the area for Sunday and Monday with wind
chills in the single digits and teens for most of that time. Models
continue to struggle with the evolution of the synoptic pattern
early next week. Cluster analysis of the 00Z ensembles showed there
was still a good chunk of ensembles leaving energy over the
southwest, and the 12Z ECMWF, while not completely cutting off an
upper low, has trended towards a deeper low over the southwest. In
any case surface high pressure over the central plains and a more
southern track to shortwave energy may keep precip chances to the
south of the area. Confidence in the forecast for early next week
is low until models converge on how the pattern will evolve.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1035 AM CST Tue Nov 25 2025

VFR conditions are forecast to prevail as dry air advection and mixing
of the boundary layer persists into this evening clearing out the low
level saturation. Winds should subside late this evening, but gusts
could continue into Wednesday morning as steep low level lapse rates
promote momentum transfer to the surface.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Wolters
AVIATION...Wolters