638
FXUS64 KOUN 131148
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
648 AM CDT Sun Sep 13 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 646 AM CDT Sun Sep 13 2026

- Hot and humid conditions through at least midweek.

- Elevated to near-critical fire weather conditions possible
  Monday afternoon across the west.

- Chance of showers and thunderstorms across western and northern
  Oklahoma by Tuesday into Wednesday.

&&

.NEAR TERM...
(Through Sunday)
Issued at 205 AM CDT Sun Sep 13 2026

Scattered showers and thunderstorms are ongoing this morning
across the northern and western Oklahoma. This convection is
occurring along and north of the effective, convectively-
reinforced cold front/out flow boundary that is being intersected
by the low-level jet. The expectation is this activity will
continue to move east-southeast and gradually decrease in
intensity and coverage with time through the morning. No severe
weather is expected.

The aforementioned outflow boundary/effective cold front will
lift to the north and dissipate during the daytime hours as
southerly winds increase. The ~594 dam subtropical ridge will be
in close proximity, which significantly decreases the chance for
showers and thunderstorms today (especially with no evident
mesoscale features like yesterday). Nevertheless, forecast
soundings do indicate a weakly capped, relatively moist
environment. Therefore, there is a low chance (10% or less) of
isolated thunderstorms across the northern half of Oklahoma this
afternoon.

Hot and humid conditions are expected with widespread triple
digit heat indices. A Heat Advisory was issued for the entire
area. Northwest Oklahoma will be on the edge of criteria; however,
since it will be quite hot for mid-September, opted to keep it
simple and include that area in the advisory given it will be hot
either way. High temperatures today will be ~15 deg F above
normal.

Mahale

&&

.SHORT TERM...
(Sunday night through Tuesday night)
Issued at 205 AM CDT Sun Sep 13 2026

The subtropical ridge will begin to move eastward on Monday with
increasing lee cyclogenesis east of the Rocky Mountains. Lee
cyclogenesis will cause a deepening surface low and attendant
trough across the Central Plains. The strengthening surface
pressure gradient will result in breezy southerly winds Monday
afternoon. 30 to 35 knots of 925 to 850 mb flow indicate the
potential for wind gusts between 30 to 40 mph across northwest
Oklahoma. While minimum relative humidity will not be overly low
(~20 to 25%), these wind speeds will likely result in elevated to
near-critical fire weather conditions across western Oklahoma
Monday afternoon. The heat will continue with a strong low-level
thermal ridge across the western/northwestern side of the
subtropical ridge. High temperatures will be in the upper 90s to
mid 100s deg F.

By Tuesday into Tuesday night, northern and western Oklahoma will
be close enough to stronger flow aloft (on the periphery of the
ridge), where there will be a chance of showers and thunderstorms
associated with a cold front. Temperatures across northwest
Oklahoma Tuesday afternoon will be highly dependent on how far
southeast the front progresses (i.e., theres a chance it could
end up being cooler than forecast). Elsewhere, the heat will
continue on Tuesday. Lighter winds and more moisture compared to
Monday should limit the fire weather risk Tuesday afternoon.

Mahale

&&

.LONG TERM...
(Wednesday through Saturday)
Issued at 205 AM CDT Sun Sep 13 2026

Above-normal temperatures will likely continue through at least
Thursday as bias-corrected probabilistic guidance indicates little
temperature spread with even the 10th percentile above-normal
through that period. High temperatures will range from the mid
90s to the low 100s deg F.

Ensemble spread increases among the global models by late in the
week into next weekend (September 18-20), which indicates the
potential for a pattern change. There is a chance the subtropical
ridge will break down as a mid-level trough digs across the
Plains. This would drive a cold front southward into the Southern
Plains. There is a 30 to 70% chance of high temperatures below 90
deg F by Saturday (30% southeast; 70% north). The coldest end of
guidance indicates a low to medium chance (5% southeast; 50%
north) of high temperatures below 80 deg F. These probabilities
increase by 10 to 20% by Sunday (i.e., the chance of cooler
weather increases later in the weekend).

Mahale

&&

.AVIATION...
(12Z TAFS)
Issued at 646 AM CDT Sun Sep 13 2026

Based on latest observational and model trends, scattered showers
and thunderstorms which are concentrated over northwest Oklahoma
should continue to shift eastward over the next two to four hours.
Mainly VFR conditions are expected. However, IFR conditions have
recently been observed at KSWO (for ceilings) and KWWR (for
visibility due to heavy rain). Even short term models have handled
this morning`s activity poorly, but indications are KPNC could see
periods of showers through at least late morning. Otherwise mid/high-
clouds are anticipated through at least mid-day with mainly
southeast/southerly winds.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 100  76  99  77 /  10   0   0   0
Hobart OK        103  77 102  77 /  20   0   0   0
Wichita Falls TX 103  77 102  77 /   0   0   0   0
Gage OK          102  76 101  77 /  30   0   0   0
Ponca City OK     97  74  98  75 /  20   0   0   0
Durant OK        102  76 101  76 /   0   0   0   0

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Heat Advisory from noon today to 7 PM CDT this evening for
     OKZ004>048-050>052.

TX...Heat Advisory from noon today to 7 PM CDT this evening for
     TXZ083>090.

&&

$$

NEAR TERM...10
SHORT TERM...10
LONG TERM....10
AVIATION...01