175
FXUS63 KTOP 131653
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
1153 AM CDT Sun Sep 13 2026

.KEY MESSAGES...

- Scattered non-severe storms linger this morning, otherwise
relatively cooler today with highs in the low 70s north to mid 80s
south.

- Multiple rounds of rainfall are possible this week, with the
greatest focus being Monday night through Wednesday morning. A few
storms could be severe with damaging wind and hail threats, and
locally heavy rainfall is also a concern.

- Confidence decreases with time, but rain chances remain in the
forecast through the end of the week. This could increase flooding
concerns if heavy rain falls repeatedly in the same locations.

&&

.DISCUSSION...
Issued at 421 AM CDT Sun Sep 13 2026

We are in zonal flow aloft as upper ridging has been pushed to the
southern tier of the CONUS, while a cutoff low spins over the
Pacific Northwest and broader cyclonic flow encompasses the rest of
the northern CONUS thanks to another low near the Hudson Bay. A
surface low sits in the eastern NM and west TX vicinity with its
frontal boundary remaining stationary in southern KS early this
morning. WAA north of the front has sustained scattered storms
across much of the CWA despite the LLJ not being overly strong at
around 25-30 kts. Storms may decrease in coverage through the
morning as the jet weakens, but with the WAA regime staying in place
through the day, am hesitant to buy into the CAM solutions that dry
us out completely earlier in the day. It would seem reasonable to at
least keep some isolated or widely scattered showery activity into
the afternoon, so held onto low chance PoPs to account for that
possibility. Outside of rain, the sfc boundary may lift north some
today with clearing skies more likely to occur south of the front.
However far north it manages to make it will determine how warm
temperatures will get. For that reason, highs in the 80s are mostly
confined to areas south of I-70 with locations north remaining in
the 70s today. Later tonight, CAMs redevelop elevated convection
along the instability gradient within the WAA regime, but vary in
its eastward/westward placement. Some solutions keep all of this
east into MO, while others include part of northeast KS. Most of
this activity shouldn`t be severe, but with effective shear around
30 kts, that will be something to monitor.

On Monday, there is good agreement on the warm air surging north
with breezy southerly winds. This brings a quick warm-up with highs
in the 90s and heat indices near 100 degrees. Dry weather is
expected in the warm sector, so the main focus for storms will be
with the approach of the cold front in north central KS during the
late afternoon and evening. Shear is modest around 25-30 kts, but
inverted-V soundings indicate a potential wind threat if an updraft
grows strong enough. The severe threat should diminish later in the
evening and overnight as instability decreases.

As we get into Tuesday, this is where this system could become more
impactful but there is still a fair amount of uncertainty. The cold
front looks to slowly sag south through the day, and its location in
the afternoon and evening will ultimately determine where the severe
and hydro threats will be greatest. With clearer skies south of the
front comes greater instability, and with slightly better shear and
more instability compared to Monday, think Tuesday presents a
slightly better severe weather setup with damaging wind and perhaps
hail up to 1 inch as potential threats. The bigger concern with time
is that storms may train over the same locations with storm motions
being parallel to the front. This along with ensemble guidance
showing Pwat near the 99th percentile indicates some concern for
locally heavy rainfall amounts. NBM currently has a 40-80%
probability of totals exceeding 2" by 12z Wednesday (mainly along
and north of I-70), though it should be noted that this is only
incorporating the coarser model guidance for now. Of the high-res
models, only the 00z and 06z RRFS go out far enough, and for now
they show a couple swaths of 2-4" indicating a more localized heavy
rain threat. Once we get within range of more CAM guidance, we
should get a better idea of the potential for any higher-end amounts
that could be more concerning, and where the heavy rain axis might
be.

The front may move around a little bit later in the week, but looks
to stall somewhere in the region. Given the uncertainty in exactly
where it will be each day Wednesday onward, temperature spreads
remain large in the ensemble guidance and PoPs continue through the
end of the week. In any case, warmer temperatures in the 80s
(possibly around 90) can be expected south of the front with cooler
temperatures in the 70s north, especially if clouds and rain linger.
The placement of the front will also be key in determining where
flooding concerns could grow, as multiple rounds of rain over the
same locations would become a problem, but if later rounds go
through areas less impacted earlier in the week, that would limit
the risk. By next weekend, we finally get a strong enough shortwave
in the area to push the front south with better agreement on cooler
temperatures.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1153 AM CDT Sun Sep 13 2026

Scattered showers and thunderstorms will continue to push
through the Topeka area through mid-afternoon. Additional
thunderstorms overnight look to stay mostly north of the main TAF
sites. Otherwise, some scattered MVFR ceilings can`t be ruled out
through tonight but VFR conditions should generally prevail. Clouds
clear out by tomorrow morning as winds begin to increase to around
10-15 kts and turn from the east to more southerly. Before this
shift to south winds occurs, some LLWS will be possible overnight,
mainly towards KMHK where the LLJ will be stronger.

&&

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

&&

$$

DISCUSSION...Picha
AVIATION...Reese