439
FXUS63 KTOP 081927
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
227 PM CDT Tue Sep 8 2026

.KEY MESSAGES...

- A weak boundary slowly moves south through Wednesday with chances
  for storms. There is a marginal risk for damaging winds and hail.

- The front is expected to bring a break from the heat, with more
  seasonal temperatures going forward.

- Off and on precipitation chances are forecast this weekend and into
  next week.

&&

.DISCUSSION...
Issued at 227 PM CDT Tue Sep 8 2026

19Z water vapor imagery showed the upper ridge was still over the
southern plains as a series of upper level waves moved across the
Pacific Northwest and northern plains. Surface obs placed a weak
boundary from northwest KS through the middle MO river valley and
into MN.

For tonight through Wednesday night, the weak boundary is going to
be the main factor in the forecast regarding temps and precip
chances. There is pretty good agreement in the operational solutions
for shortwave energy to pass north of the forecast area late
tonight. This should help slowly push the surface front into the
area and eventually south of the forecast area Wednesday. Since most
of the dynamics are north, precip chances will be tied mainly to
instability and convergence along the front. Am a little hesitant to
go with the categorical POPs from the NBM since CAMs tend to show
more discreet storms. The exception to this is Wednesday night with
the boundary should still be near east central KS as the low level
jet kicks in. Have left some higher POPs in the forecast for this
period. There is a low potential for severe storms this evening and
again Wednesday afternoon as MUCAPES increase to near 4000 J/kg. But
the boundary is progged to remain south of the better westerlies
both tonight and Wednesday afternoon resulting in meager deep layer
shear. So I anticipate some pulse storm activity could occur and be
capable of damaging winds and perhaps some hail during the
initiation of convection. As long as storms remain rather discreet,
flooding concerns should be limited. But there is forecast to be
plenty of moisture available with a deep warm layer aiding in warm
rain processes. So it is not out of the questions some isolated rain
amounts between 1 and 2 inches.

As for temperatures Wednesday, models show highs could potentially
get into the upper 90s across Coffey and Anderson counties before
the boundary moves through. This would push heat indices back into
the triple digits for parts of east central Kansas. But I think
increasing cloud cover and the prospects for convection turning over
the boundary layer could limit the duration of any temperatures like
this and have held off on issuing a heat advisory for Coffey and
Anderson counties. Later shifts can take another look at this.

Some of the nicest weather is expected for Thursday before another
boundary moves through the central plains Friday night and Saturday.
This should bring another chance for showers and thunderstorms. But
Thursday should see highs in the 80s with a little less humidity.
Southerly return flow Friday is expected to push temps back into the
lower 90s. Will need to watch out for some possible warm air
advection storms late Thursday night and Friday morning. The 06Z NAM
was wanting to develop some elevated storms, but the most recent
guidance shows the mid level moisture is a little lacking within the
warm air advection pattern. So the forecast remains dry for now.

By Sunday through Tuesday, the 00Z ensemble data starts to show
greater spread is potential outcomes with some disagreement in the
amplitude of the shortwave activity. Temperatures spreads by this
time increase to betweeen 10 and 15 degrees while the location and
timing of a surface front varying as well. So while the 12Z
operational GFS/ECMWF seem to be in reasonable agreement, there is a
little lower predictability than the operational solutions would
suggest. Have stuck with the NBM/WPC forecast which has a broad
brush of POPs and temps that are a little more seasonal.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1157 AM CDT Tue Sep 8 2026

with better forcing for convection remaining north of the area, think
TS chances will be tied to the FROPA. CAMs show mainly scattered
convection along the boundary so will include a PROB30 group for now
when the front moves into the terminals. The RAP shows some
indication for restricted CIGS post frontal, but the NAM/GFS are not
as aggressive with the lower clouds. So have kept a VFR forecast for
now and will let later shifts take another look at low clouds behind
the front.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
Extreme Heat Warning until 7 PM CDT this evening for KSZ008-KSZ009-
KSZ010-KSZ011-KSZ012-KSZ020-KSZ021-KSZ022-KSZ023-KSZ024-KSZ026-
KSZ034-KSZ035-KSZ036-KSZ037-KSZ038-KSZ039-KSZ040-KSZ054-KSZ055-
KSZ056-KSZ058-KSZ059.

&&

$$

DISCUSSION...Wolters
AVIATION...Wolters