760
FXUS63 KTOP 022320
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
620 PM CDT Tue Sep 2 2025

.KEY MESSAGES...

- Potential for a few severe thunderstorms Wednesday afternoon
  and evening as a cold front moves through the area. Large hail
  will be the main hazard, with some damaging winds also
  possible.

- Cool temperatures with occasional rain chances persist through
  the weekend.

&&

.DISCUSSION...
Issued at 217 PM CDT Tue Sep 2 2025

A weak upper low continues to drop south over eastern Kansas this
afternoon, supporting a few remnant sprinkles over northeast Kansas.
Otherwise, clouds are gradually thinning out as the low moves away
from our area. Attention then turns to a much stronger upper low
that will move southeast over the Upper Midwest tonight into
tomorrow, driving a cold front southeast through our area. Sunshine
and southwest winds ahead of the cold front will help us climb into
the 80s during the afternoon, for once not too far away from
seasonable values. The heating will combine with moisture advection
and steep mid-level lapse rates to produce around 1500-2000 J/kg of
ML CAPE along the front, sufficient for the development of scattered
thunderstorms after 3-4 PM. Increasing mid-level flow in
advance of the upper low will allow for effective bulk shear of
around 40 kts. This will be supportive of a few initial hail-
producing supercells, followed by gradual upscale growth along
the front with increasing wind potential. Given long, straight
hodographs and the steep mid-level lapse rates, there is some
potential for hail golfball sized or bigger. There is still some
uncertainty with the exact speed of the front, but a current
middle ground consensus brings the front to around I-70 by late
afternoon and early evening. Assuming this holds, this would
keep the main severe weather risk near and south of the
interstate. A faster frontal speed would keep storm coverage
lower and even further limit the northern extent of the severe
threat.

Cooler and drier air quickly is ushered in behind the front for
Thursday morning as surface high pressure races across the area. So
after a chilly start to the day, winds actually turn southwesterly
as a secondary cold front approaches with another upper wave.
Moisture will be more limited with this front, but a few more
showers and thunderstorms could still occur Thursday night as the
front passes through, followed by lingering showers into Friday.
Cooler air again arrives behind this front, keeping highs Friday
near 70 and Saturday morning lows near 50. The upper low over the
eastern CONUS will gradually weaken and move away over the weekend.
However lingering northwest flow and surface riding will keep cool
temperatures around. Highs stay mostly in the 70s with lows in
the 50s, along with some low-end (20-30%) rain chances.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 620 PM CDT Tue Sep 2 2025

Mainly VFR conditions are expected. Band of MVFR cigs at KMHK
should dissipate within the next hour or so. Shallow ground fog
may develop early Wednesday morning, especially in the river
valley at KTOP/KMHK. Have input a TEMPO group for reduced VSBY.
Light winds from the west-southwest become northerly late in
the period as a cold front moves through. Showers and storms are
possible along the front as well, but confidence in location
and timing is too low to include mention in this TAF period.

&&

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

&&

$$

DISCUSSION...Reese
AVIATION...Flanagan