832
FXUS63 KTOP 301954
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
254 PM CDT Wed Sep 30 2026

.KEY MESSAGES...

- Periods of rain continue through Thursday, which could be heavy at
times. An additional 1.5 to 3" are forecast with locally higher
amounts around 4" possible, which leads to increased flooding
concerns for areas that saw the most rain last night.

- A few severe storms are possible this afternoon and evening,
mainly west of Hwy 75. These may produce damaging winds or a tornado
or two.

- Dry weather returns for the weekend into early next week with highs
  in the 60s and 70s.

&&

.DISCUSSION...
Issued at 253 PM CDT Wed Sep 30 2026

Upper low continues to spin over the Four Corners region while the
main westerlies are along the US-Canada border. The sfc low has been
slowly moving through the OK/TX panhandles into southwest KS early
this afternoon. Strong synoptic lift driven by WAA and divergence
aloft has brought a broad area of continuous light rain with pockets
of moderate to heavy rain at times this morning and afternoon, all
within an environment comprised of Pwat around 2" with the moisture
axis overhead. Today`s rain has mostly impacted central and parts of
northeast KS, much of the same areas that saw the heaviest rainfall
last night. Washington, Marshall, and Nemaha Counties had a swath of
2-3" last night into this morning with light rain lingering into
this afternoon, so this area would be the most primed for flooding
issues with any additional heavy rainfall between now and Thursday.

The warm front has washed out with the ongoing rain and is not well-
defined. Our sfc winds are mainly southerly, but are backed to the
southeast towards central KS (closer to the center of the low).
Visible satellite shows the dry slot working its way through
southwest KS, and the thinking is once that arrives into central KS,
that should allow for better destabilization with SBCAPE between 500-
1000 J/kg. It remains questionable how much time the atmosphere will
have to become unstable enough to develop severe storms in our area,
but the increasing LLJ late this afternoon into early evening will
only help low-level shear profiles. With veering winds, 0-3km shear
around 40 kts and 0-3km SRH around 200 m2/s2, it may not take as
much instability as one would expect to get a strong enough storm to
produce a quick tornado or two. The window of opportunity looks
rather short, especially as our area would be on the eastern fringes
of the threat and would take longer to see enough clearing, but will
need to look out for this potential particularly between 4-8pm today.

Outside of the severe risk, heavy rain and flooding remains the
biggest threat especially for those areas that already received
heavy rain as mentioned earlier. It wouldn`t take much additional
rainfall for the northernmost counties in the watch to exacerbate
flooding issues or lead to more flooding. Once the bulk of the rain
this evening moves north and east of the area, there should be a
more notable break overnight, although a few scattered showers are
still possible along the KS/NE border. Closer to daybreak Thursday,
another surge pushes north out of OK into east central KS and
coverage also increases along the cold front stretched across
northern KS. This front will gradually move west to east across the
area throughout the day, leading to wet weather area-wide. The
heaviest rain should come to an end in northern KS during the
afternoon, while east central KS should see continued rain into the
early evening, becoming lighter later into the night. A general 1.5
to 3" with locally higher amounts around 4" should be expected on
top of what has already fallen. Some of this is in locations outside
of the watch, with the 12z HREF showing some high-end potential for
3-4" south of I-35. However, this area is not nearly as saturated as
those further north, so opted to leave the Flood Watch as is.

The upper system weakens into Friday with the front passing east,
leading to a transition to zonal and eventually northwest flow
aloft. Several days of dry weather are expected, a welcome change to
help us dry out after the wet weather this week. Temperatures will
be coolest on Friday immediately behind the boundary with highs in
the 60s followed by lows in the 40s Saturday morning. We then warm
slightly with highs in the 70s and lows in the 50s the rest of the
forecast period.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1232 PM CDT Wed Sep 30 2026

Rain has been more persistent at MHK and expect that to continue to
be the case through the afternoon, whereas further east at TOP/FOE,
light rain is only just starting to get near terminals. Confidence in
TS still isn`t high enough to do any more than PROB30 groups at all
sites, although even without convection there could still be periods
of moderate to heavy rain that result in IFR vsby, as we`ve already
seen at times. There should be somewhat of a break later tonight and
overnight before rain fills back in mid to late morning. Cigs look to
become lower in the back half of the period. Was hesitant to go to
IFR as early as guidance shows, as it appears to be overdone with
lower cigs with current conditions, but there`s enough agreement that
it seems to be worth a mention for at least part of the morning.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Thursday afternoon for KSZ008-KSZ009-KSZ010-
KSZ011-KSZ012-KSZ020-KSZ021-KSZ022-KSZ023-KSZ024-KSZ026-KSZ034-
KSZ035-KSZ036-KSZ037-KSZ038-KSZ039.

&&

$$

DISCUSSION...Picha
AVIATION...Picha