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000
FXUS63 KTOP 080849
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
249 AM CST Fri Dec 8 2023

.DISCUSSION...
Issued at 249 AM CST Fri Dec 8 2023

Key Messages:

- 20-50% chance for light rain this afternoon and evening, mainly
  across east central Kansas.

- Dry with seasonal temperatures Saturday into the middle of next
  week.

Discussion:

Several perturbations in the flow are evident in water vapor imagery
across the western and central CONUS this morning. Mid and high
clouds are streaming overhead as a wave approaches from the
southwest with another wave following closely behind. A closed low
over North Dakota has pushed a weak cold front into the area; this
front`s progression has slowed and it currently resides along a St.
Joseph to Topeka to Emporia line. Boundary layer moisture remains
high ahead of the front with dewpoints in the upper 40s to near 50
which, coupled with light winds in the trough axis, could
(50%) support some patchy fog this morning.

A surface low centered in the TX/OK panhandles will lift northeast
along the cold front through the day today as the second wave ejects
across the Plains. Isentropic ascent to the north of the surface low
will generate light rain mainly for areas along and southeast of the
Kansas Turnpike beginning late this morning and ending by late this
evening. Moisture depth is limited with forecast soundings showing
saturation in the 850-700mb layer with dry air above and below this
layer. Another weak perturbation could (15-20%) generate some light
rain farther northwest during the evening, but again moisture
quality is an issue. Soundings in this area show mid-level
saturation, but depict very dry air below 600-700mb. Most of the
precipitation falling into this dry layer is likely to evaporate
before reaching the ground, but some drizzle or light rain making it
to the surface is plausible. Confidence remains high (>95%) in all
precipitation falling as rain as precipitation ends before
temperatures cool enough to support any wintry precipitation.

Northwest flow settles in for the weekend with a tight pressure
gradient leading to breezy conditions on Saturday before winds relax
for Sunday. Highs will be near climatological norms this weekend in
the mid 40s. Seasonable temperatures and dry conditions are expected
through the middle of next week when uncertainty increases as a
closed low develops across the southwest US by Wednesday.
Variability is large in how this system evolves, but precipitation
chances will increase sometime late next week once the system ejects
east.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1050 PM CST Thu Dec 7 2023

VFR at terminals as passing LLJ at 2kft shifts eastward,
decoupling the boundary layer as winds become light and VRB. FROPA
from the northwest veers winds to the north and northeast aft 17Z
at KMHK and 18Z at KTOP/KFOE along with increasing mid level
clouds. SCT showers are expected to develop aft 20Z south and
east of sites so have opted to not mention.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

DISCUSSION...Flanagan
AVIATION...22