979
FXUS63 KTOP 081106
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
606 AM CDT Mon Jun 8 2026

.KEY MESSAGES...

- Hot and humid conditions are forecast for Tuesday and a heat
  advisory has been posted from noon until 9pm.

- There is a 30-50% chance of storms late this afternoon and evening.
  If storms form, they could become severe.

- A weak cold front is expected to move into the area Wednesday and
  could bring a chance for more thunderstorms and severe weather.

&&

.DISCUSSION...
Issued at 306 AM CDT Mon Jun 8 2026

07Z water vapor imagery showed a shortwave lifting towards the Upper
Midwest with a broad upper trough over the western U.S. Surface obs
showed a very humid boundary layer across the forecast area with
dewpoints around 70 degrees. An area of low pressure was noted over
the CO high plains.

For today and tonight, trying to figure out what could trigger the
next round of showers and thunderstorms is the main challenge.
Models show a conditionally unstable airmass with MUCAPE values
around 4500 J/kg while 0-6km shear improves to around 30KT this
afternoon. So the environment will be favorable for convection. But
there isn`t a lot of synoptic forcing and isentropic surfaces don`t
show a lot of lift until after sunset. Models do show an inverted
surface trough setting up across the forecast area this afternoon as
the surface low moves into southwest KS. This could act as a focus
for convergence and thunderstorm development. But surface winds are
only expected to be in the 5 to 15 mph range and limit low level
convergence over the forecast area. Better convergence may occur
across central and western KS and the CAMs suggest a couple isolated
supercells may form or perhaps a small MCS that eventually propagates
along the instability axis into east central and southeast KS. The
forecast has a broad brush of 20-30 percent chance POPs by the early
afternoon given the expected instability and lack of inhibition.
Chances are a little higher through the mid evening hours for areas
south of I-70 to account for the CAMs showing storms in this area.
Would like to see better forcing or lift to have better confidence
in the forecast so have left POPs in the 40-50 percent range this
evening. If bulk shear remains around 30KT, then storms could have
an organized updraft with a risk for large hail and damaging winds.
A tornado risk will depend local winds, but the general motion of
the storms to the southeast would have them moving into a weaker
shear environment and probably why the CAMs tend to show storms
evolving into more of an MCS. PWs should still be very high this
evening, so thunderstorms will also be capable of very heavy rain.
Highs today are forecast to be in the middle and upper 80s with an
easterly component to low level winds and scattered to broken cloud
cover helping to keep highs from getting much warmer.

By Tuesday the models show a better southwesterly low level flow
developing and warmer air from the southwest advecting into the
area. Unfortunately this doesn`t seem to dry the boundary layer out
much and most of the guidance is pointing to a hot and humid day.
The NBM is giving mean apparent temps around 105 degrees for a large
part of east central KS and especially in the river valleys. The
HREF also shows probabilities of exceeding 103 degree heat indices
of 50 percent or better. Additionally the humid airmass is expected
to keep overnight lows in the lower and middle 70s and limiting much
relief from the heat overnight. So went ahead and posted a heat
advisory for much of east central and parts of northeast KS Tuesday
afternoon. The only concern for temps not reaching the advisory
would be a shortwave forcing convection, but there isn`t much of a
signal for this as models keep the upper trough and shortwave energy
west of the forecast area.

For Wednesday and into the weekend, models show the pattern shifting
east with a closed upper low setting up over the northern plains and
broad cyclonic flow over the central plains. This should allow for
occasional cold fronts to move through the area. The good news is
this should keep highs in the 80s for the end of the week and
weekend. But there will also be occasional chances for showers and
storms, especially with the frontal passages. The first weak front
is progged to move into the area Wednesday afternoon and could act
as a focus for thunderstorms. Again there looks to be plenty of CAPE
along the boundary with bulk shear around 40KT. So there should be a
risk for severe storms along the front Wednesday afternoon and
evening. This also brings additional uncertainty into the temp
forecast and whether a heat advisory will be needed for Wednesday.
For now have stuck with the NBM which seems to fit with the
operational runs reasonable well.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 606 AM CDT Mon Jun 8 2026

Model consensus is for IFR stratus to continue overspreading the
region with CIGS gradually lifting through the afternoon while
maintaining an MVFR CIGS. There is a chance for TS overnight, but
confidence in them impacting the terminals is marginal since CAMs
have not shown much consistency. Since precip chances are late in the
forecast period, will not include a mention in the forecast at this
time.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from noon to 9 PM CDT Tuesday for KSZ022-KSZ023-
KSZ024-KSZ026-KSZ036-KSZ038-KSZ039-KSZ040-KSZ054-KSZ055-KSZ056-
KSZ058-KSZ059.

&&

$$

DISCUSSION...Wolters
AVIATION...Wolters