186
FXUS63 KTOP 152309
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
609 PM CDT Tue Sep 15 2026

.KEY MESSAGES...

- Occasional showers and thunderstorms are expected this afternoon
  and through the night, especially for Northeast Kansas.

- There is a risk for severe storms with damaging winds the main
  concern through this evening. Torrential rain could lead to
  flooding too.

- Hot weather is expected to stick around through the end of the
  week. Showers and storms are possible this weekend with cooler
  temperatures expected by next week.

&&

.DISCUSSION...
Issued at 158 PM CDT Tue Sep 15 2026

At 19Z the forecast area was under southwest flow aloft per the
latest water vapor imagery. An upper trough was noted over the
Pacific Northwest while upper ridging remained over the southeastern
U.S. Surface obs show a frontal boundary bisecting the forecast area.
North of the boundary, cloud cover and occasional rain has kept
temps in the 60s and 70s. South of the boundary with good insolation,
temps had warmed into the lower and middle 90s.

The latest NAM and RAP runs continue to show lift over the surface
boundary increasing this afternoon and persisting through the night.
A moderately unstable airmass south of the boundary is setting up
as MUCAPE values increase to between 3000 and 4000 J/kg with bulk
shear of 30 to 40KT. So there remains a risk for severe storms.
Inverted V soundings and DCAPE near 1000 J/kg support a damaging
wind risk through this evening along and south of the boundary. Hail
may be hard to come by unless there is some strong mid level
rotation. The RAP analysis suggests freezing levels remain at or
above 15 KFT. Models also show very high precipital water values
around 2.25 inches. This would be near record levels for mid
September and the reason the forecast anticipates torrential
rainfall with the storms. With the persistent lift over the boundary
through the night, there could be multiple waves or storms with
heavy rainfall. Have not made any changes to the flood watch as it
highlights the most likely area to see multiple rounds of heavy
rain.

With the lift breaking down Wednesday morning, showers and storms
should lift to the north and east of the area Wednesday morning.
Then hot and dry weather is forecast for Thursday and Friday as the
upper ridge retrogrades over the southern plains and middle MS river
valley. This is expected to push precip chances mainly to the north
of the forecast area while highs in the 90s persist. Will need to
keep an eye on the warm air advection pattern setting up Thursday
morning for some elevated showers. Some of the short term models are
showing some potential while the NBM still has a dry forecast going.

The operational models continue to show an upper trough moving from
the northern Rockies into the plains this weekend. Ensemble data
still shows a decent spread in the timing and strength of the
trough. But the overall trend is noted in most guidance with chances
for showers and storms and cooler temps moving in. The NBM/WPC
forecast has a broad brush of POPs in the forecast due to the large
spread and lower predictability. The 12Z ECMWF and GFS seem to
highlight Saturday night and Sunday and the window for the front to
move through the central plains. This is when the higher POPs are
forecast to occur.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 603 PM CDT Tue Sep 15 2026

VFR to high end MVFR to start forecast period with numerous TSRA
anticipated to train across terminals overnight. Cigs quickly fall to
IFR and LIFR by 10Z as the bulk of the precipitation shifts to the
east. Coverage of showers becomes more widely scattered thereafter
before diminishing in the mid morning period. Other than gusty,
variable winds within the storms, overall winds weaken below 10 kts
overnight, veering to the southeast tomorrow afternoon as stratus
improves to MVFR.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Wednesday afternoon for KSZ009-KSZ010-KSZ011-
KSZ012-KSZ021-KSZ022-KSZ023-KSZ024-KSZ026.

&&

$$

DISCUSSION...Wolters
AVIATION...Prieto