576
FXUS63 KTOP 031710
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
1210 PM CDT Thu Sep 3 2026

.KEY MESSAGES...

- An Extreme Heat Warning is now in effect through Tuesday evening
  with heat indices of around 100 to 108 degrees each afternoon.

- The pattern finally changes late next week with the first real
  rain chances and near normal temperatures.

&&

.DISCUSSION...
Issued at 217 AM CDT Thu Sep 3 2026

The 00Z RAOB data show the H5 ridge holding over the southern and
central Plains with weak flow directly overhead and southwest flow
displaced over the Intermountain West into the northern Rockies.
The Pacific Northwest trough and associated upper low remain the
primary features of consequence upstream, with tropical moisture
remaining along the Gulf coast. At the surface, a quasi-stationary
boundary sits north of the area in Nebraska with lee troughing to
the west, mainly over central into western Kansas. The entire CWA
remains under the heat dome once again today. On Wednesday, heat
indices touched the 103 to 106 range around midday before deep
mixing scoured afternoon dewpoints into the low 60s, trimming heat
indices back toward the air temperature by late afternoon. The NBM
continues to run both too cool on highs and too moist on afternoon
dewpoints. This has been taken into account for this forecast
cycle as well.

Early this morning, weak ascent along the 305 K isentropic surface
over north central Kansas may squeeze out a few showers. Forecast
soundings keep a deep dry layer below cloud bases, so anything
that falls fights sub-cloud evaporation and coverage stays isolated
at best. Chances hold below 15 percent and end by mid morning,
with most locations staying dry and any measurable rainfall
confined to a few spots.

The heat headline driver remains focused on the dewpoint question
and the depth of adiabatic mixing, and the HREF ensemble members
suggest this as well. Thursday afternoon dewpoint spread at Topeka
runs from near 60 in the drier members to near 70 in the moister
ones, and that range is the difference between heat indices near
100 and heat indices in the middle 100s. The drier solutions have
verified each afternoon by mid afternoon, though not before heat
indices reached advisory criteria around midday, and that midday
window is what the Heat Advisory now in effect through Saturday
evening covers. Beyond Saturday, southerly flow persists and the
ensemble mean keeps afternoon dewpoints in the middle 60s with H85
temperatures holding in the middle 20s C, so Sunday and Labor Day
sit on the advisory fence as well. If the deeper mixing keeps
verifying, criteria likely remain marginal; if the moistening
trend wins, an extension through the full weekend will likely win
out. Either way the heat itself is slow to recede: highs in the
upper 90s to near 100, warmest north central where mixing depths
are deepest, with overnight lows in the middle and upper 70s
keeping record warm minimums in play through Saturday morning.

The ridge holds through the holiday weekend and into early next
week. Ensemble data suggest the mid level heights over the area
stay elevated with tight member agreement through Tuesday, and WPC
cluster analysis keeps positive height anomalies over the central
US in every cluster into the middle of next week. Slight rain
chances along the Nebraska border early next week most likely
reflect the growing spread rather than an organized signal. The
real change appears to arrive late next week. Ensemble heights
fall sharply around Thursday as the Pacific trough finally ejects
into the Plains, H85 temperatures step down several degrees C at
the same time, and the cluster favoring that evolution is weighted
toward the ECMWF membership. That system may bring the first
meaningful rain chances in two weeks and the first stretch of near
normal temperatures since around the third week of August.
Confidence in the pattern change is increasing slightly based on
the most recent trends; confidence in the exact day remains low.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1205 PM CDT Thu Sep 3 2026

VFR conditions persist. Southerly winds sustained 10-15 kts will gust
to 20-25 kts at times this afternoon before diminishing around
sunset. The LLJ looks to increase to around 35 kts overnight, but
low-level profiles favor more of a turbulence setup over LLWS.

&&

.CLIMATE...
Issued at 212 AM CDT Wed Sep 2 2026

Record highest minimum temperature information:

                      Record                   Forecast

September 4  Topeka     78, set in 2014            74
 Concordia  79, set in 1954            75

September 5  Topeka     76, set in 1983            75
 Concordia  78, set in 1899            76

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
Extreme Heat Warning until 7 PM CDT Tuesday 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...Drake
AVIATION...Picha
CLIMATE...Drake/Poage