617
FXUS64 KOUN 061056
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
556 AM CDT Sun Sep 6 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 125 AM CDT Sun Sep 6 2026

- Ongoing heatwave continues through at least midweek with triple
  digit heat indices and lows well above normal.

- Very low chances for rain/storms this afternoon across northern
  and eastern parts of the forecast area on Sunday and Monday
  afternoons.

- Possible pattern shift by late week introducing low rain chances.

&&

.NEAR TERM...
(Through Sunday)
Issued at 125 AM CDT Sun Sep 6 2026

The near term will be marked be heat and isolated pop-up
thunderstorms.

Morning lows will stay up in the mid to upper 70s, followed by
afternoon highs reaching into the triple digits. Heat indices
will largely follow the moisture gradient with the highest values
along the Red River, within the festering heat box of north
central Oklahoma, and east of I-35 (105-110 degrees), especially
southeast Oklahoma. With drier air in place, northwest Oklahoma
will see heat indices closer to 100. The current heat advisory is
well configured with this forecast, so will not make any
adjustments to the area.

The signal for rain this afternoon is weak, with a few CAMs
showing very isolated convection. These will be diurnally driven
pop-up thunderstorms with little chance of meaningful rainfall.
Have included 10% PoPs for this possibility with most of the area
expected to remain dry.

Overnight lows will again stay up in the mid to upper 70s,
offering little relief from the daytime heat.

Day

&&

.SHORT TERM...
(Sunday night through Tuesday night)
Issued at 125 AM CDT Sun Sep 6 2026

Continuing under the blocking ridge, Monday appears very similar
to Sunday both in terms of heat and low chance pop-up
thunderstorms. Cumulative heat stress (including overnight lows
running 5 to 10 degrees above normal) will put our heat risk into
the major to extreme category across most of the area through
Wednesday. For now, we`ve expanded the heat advisory into Monday.

The signal for diurnal thunderstorms disappears on Tuesday. While
there is the caveat that this is now outside the CAM window, this
does fit with the synoptic setup as the ridge shifts slightly
eastward. Otherwise, our hot and dry pattern continues with
similar heat indices to previous days (with a subtle trend toward
105+ heat indices covering a slightly larger area).

The aforementioned eastward shift of the ridge will allow a low
chance (10-20%) for showers and storms to make it into northwest
Oklahoma late Tuesday night / early Wednesday morning.

Day

&&

.LONG TERM...
(Wednesday through Saturday)
Issued at 125 AM CDT Sun Sep 6 2026

The ridge begins to flatten Wednesday as several waves begin to
make their way through the northern flow. Most models (80-90%)
depict Wednesday as hot and dry like previous days, though a few
ensemble members (~10%) suggest that we could see thunderstorms
approach northern Oklahoma from Kansas.

Thursday through the end of the week redevelops the ridge over the
western conus, putting us in the path of several waves in the
upper flow. This will bring back low chances for rain (10-30%) and
a chance for some relief from the heat. High temperature
uncertainty jumps on Thursday across northern Oklahoma--where the
middle 50% (interquartile range) of potential outcomes spans a
10-degree range--before spreading farther south toward the
weekend. Even with the potential cooling, the likelihood of daily
highs reaching or exceeding 100 degrees remains moderate to high
(50-80% probability, highest in north Texas) through Saturday. Key
factors determining whether relief arrives and any rain chances
will be the position / strength of the ridge and timing of
approaching upper level waves.

Day

&&

.AVIATION...
(12Z TAFS)
Issued at 556 AM CDT Sun Sep 6 2026

VFR conditions will continue on Sunday, with a generally modest
south-southeasterly breeze and diurnal cumulus expected during
this time. Have maintained PROB30 mentions at terminals along/east
of Interstate 35 in Oklahoma for Sunday afternoon and evening,
though minimal terminal (and resultant category) impact remains
expected.

Safe travels!

Ungar

&&

.FIRE WEATHER...
Issued at 125 AM CDT Sun Sep 6 2026

While no particular day stands out as problematic (RH values
generally stay above 25 percent), hot temperatures and very dry
fuels (90th+ percentile ERCs) warrant keeping a close eye on
conditions.

Day

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 100  76 100  77 /  10   0  10   0
Hobart OK        101  76 101  77 /   0   0   0   0
Wichita Falls TX 102  75 102  77 /   0   0   0   0
Gage OK           99  73 100  74 /  10   0   0   0
Ponca City OK    100  75 100  76 /  10   0  10   0
Durant OK        103  76 103  76 /  10   0  10   0

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Heat Advisory from noon today to 7 PM CDT Monday for OKZ006>008-
     011>013-017>020-023>032-035-037>048-050>052.

TX...Heat Advisory from noon today to 7 PM CDT Monday for TXZ085-086-
     088>090.

&&

$$

NEAR TERM...14
SHORT TERM...14
LONG TERM....14
AVIATION...09