117
FXUS64 KOUN 140350
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
1050 PM CDT Tue Oct 13 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 1014 PM CDT Tue Oct 13 2026

- Severe thunderstorms possible this evening and tomorrow
  afternoon/evening night primarily along and northwest of I-44.

- Multiple rounds of heavy rain expected between now and Thursday
  morning with an increasing flash flood risk.

- Colder and drier airmass arrives late Thursday, with weather
  becoming cool and pleasant by the weekend.

&&

.NEAR TERM...
(Rest of today and tonight)
Issued at 211 PM CDT Tue Oct 13 2026

Near-term forecast concerns: Record high temperature potential this
afternoon, severe storms this afternoon and evening, flood risk
increasing toward daybreak.

Discussion: Our fall storm begins late this evening and tonight.
Prior to that, heating toward record temperatures has been
interrupted somewhat by the development of moist advection stratus
this morning, particularly along and southeast of I-44 within a
corridor of 73-75 dewpoints. Still, breaks in cloud cover (and total
sunshine in northern/western Oklahoma) have warmed temperatures into
the mid-to-upper 80s by early afternoon. With 4-6 more degrees of
warming, we`ll reach those low-to-mid 90s that were anticipated for
much of the area.

By the peak of diurnal heating, storm development will be ongoing
across southern Kansas along a slowly-sinking cold front. While this
activity will remain just to our north this evening, can`t rule out
thunderstorms/heavy rain in far northern Oklahoma. The more certain
zone for storms this evening will be across western Oklahoma and
western north Texas as convection develops and moves east off of the
dryline. Deep-layer shear of 50 knots will support updraft
organization, though initially weak low-level shear will tend to
lead to upscale growth into clusters by the time storms arrive in
our area this evening. The severe risk will be somewhat limited by
nocturnal stabilization, though dewpoints in the upper 60s to low
70s will keep the boundary layer from fully decoupling. In all
likelihood, we will see several severe thunderstorms capable of
damaging winds and perhaps one or two storms with favorable
storm/LLJ interactions to contain a tornado risk.

This line will move eastward tonight, likely weakening as it
approaches I-35 and moves into higher 500 mb heights. By late
tonight, the low-level jet will be matured and veering across the I-
40 corridor in western Oklahoma. This will trigger warm advection
storms to redevelop within an extremely tropical (PWATS of 2.0 to
2.25 inches) airmass before or around daybreak. The severe risk will
be limited with those storms (though can`t rule out low-level
rotation within any more pristine airmass pockets), but very heavy
rainfall and flooding will start to become more prominent.

Meister

&&

.SHORT TERM...
(Wednesday through Thursday night)
Issued at 211 PM CDT Tue Oct 13 2026

Short-term forecast concerns: Escalating flood risk from Wednesday
morning through Thursday morning, severe risk Wednesday afternoon
into Wednesday night, cold front arrival with falling temperatures
on Thursday.

Discussion: Environment is set up for impactful flash flooding
somewhere in our area tomorrow morning through Thursday morning. How
impactful, what location, and specific timing remain the biggest
questions. The upper-level low will be slow to lift northeastward;
tomorrow morning it will be near the Four Corners, and by Thursday
afternoon it will just be leaving Colorado into Nebraska as the
polar jet absorbs it. Because of this, a surface low will develop
and take the rough track of (an extremely weak) panhandle hook from
southeast Colorado to northern Oklahoma to eastern Iowa. All of this
synoptically speaks to why we should expect the cold front to be
slower to move south despite repeated convective reinforcement as
persistent height falls counteract it.

Into this environment we will see several rounds of thunderstorms
from Wednesday morning through Thursday morning. The round tomorrow
morning will be driven by the decaying LLJ. There may be break
before more storms in the afternoon as instability increases south
of the front, or the two rounds may just end up merging. Regardless,
more storms will form along and north of the cold front and last
through Wednesday evening. This seems to be the period of greatest
severe potential through this event, particularly along the front
near/after sunset as the low-level jet again ramps up. Any bowing
structures or discrete supercells in this extremely tropical airmass
would be capable of wet microbursts and/or brief tornadoes. Our
expectation is that those pockets of pristine, untouched warm sector
will continue to shrink as the night goes on, reducing near-surface
instability and the severe risk.

However, the flash flood risk will only continue to increase with
each round of thunderstorms. REFS/HREF guidance both suggest a final
round of thunderstorms as the trough begins to kick out and the low-
level jet veers early Thursday morning. This pattern (veered
LLJ/favorable propagation vectors, extreme PWATs, weak instability,
rather slow storm motions, prior thunderstorms) checks all of the
boxes for flash flooding. The location of this axis/MCS is still in
question, with the NAM somewhat surprisingly much to the northwest
of the remaining guidance. The consensus of convection-allowing
models would put that rainfall axis near or just northwest of I-44
from about Hobart to Stillwater. This flash flood risk looks like it
will be maximized for the Thursday morning commute.

It`s worth noting that the official QPF gridded forecast that we
receive from the WPC is rather bearish on rainfall amounts. This
guidance shows about 1-3 inches of rain falling in a box bounded by
Alva, Arnett, Wichita Falls, and Seminole. Often times, our gridded
forecast runs hot compared to reality (for example, two weeks ago
our forecast was initializing at 3-5 inches of rain across most of
the area which was well above what the median storm total ended up
being). There are both synoptic and model-input-based reasons to
expect that the usual overestimating bias may not apply here, at
least across a southwest-to-northeast axis. The synoptic reasons are
outlined above; the model input reason boils down to the usual trend
we see here, where global models are gung ho on widespread rainfall
totals leading into a storm system which are then tempered by CAMs
coming in and showing features like dry slots, cold advection
regimes, and other details that reduce the forecast. Since model
blends like NBM include both global and CAM models, they then end up
too high with QPFs when the CAMs verify closer to correct. In this
case, though, CAM guidance (particularly the 12Z REFS and HREF) are
much wetter than anything that global/medium-range models have
shown. The REFS and HREF both show ensemble mean totals of 4-6
inches (and individual members have higher maximums) near/just
northwest of the OKC metro through Thursday, which could lead to
rather serious flash flooding. This is a rather unusual case for us
forecasters, so there`s quite a bit of uncertainty regarding just
what the higher-end rainfall totals could be. Bottom line: while we
do usually see a QPF high bias in our official forecast, there are
reasons to consider that this case may be better-calibrated or even
biasing low, with a much higher ceiling for flash flood potential.

The rain event will come to an end Thursday as a strong polar trough
sweeps east through Canada and pressure rises kick a much
colder/drier airmass into our area. Would expect a several-hour
window of cold showers/drizzle to continue after the frontal passage
as dewpoints rapidly drop, but the lightning risk will come to an
end shortly after frontal passage. High temperatures on Thursday
will be set early in the day in many spots.

Meister

&&

.LONG TERM...
(Friday through Monday)
Issued at 130 AM CDT Tue Oct 13 2026

The aforementioned cold front will bring a high confidence
(60-80%) chance of temperatures remaining below 60F on Friday
across areas from northwestern to central Oklahoma. Across
southern and southeastern Oklahoma and western north Texas, there
is a 20-30% chance of temperatures staying below 60F on Friday.

By Saturday, daytime temperatures will rebound slightly as the
cold air advection weakens under clear skies. Mostly clear skies
will help overnight lows Friday into Saturday morning to get down
into the 40s across most locations, and into the upper 30s in
northwestern Oklahoma. There is high confidence in dry conditions
through the remainder of the weekend and into next week, with a
steady warming trend into early next week. By Monday, highs will
likely get back into the 70s across the entire area.

Bunker

&&

.AVIATION...
(06Z TAFS)
Issued at 1014 PM CDT Tue Oct 13 2026

Multiple rounds of thunderstorm activity across western Oklahoma will
be increasing eastward impacting all of our terminals except for
KDUA in southeast Oklahoma through the entire forecast period.
Terminals KDUA has a 30% chance for storms after 00Z. Terminals
could degrade to at least MVFR or down to an IFR category with
storm activity passing over with some reduction in ceilings but
mostly visibilities in to heavy rain. A cold front nearly stalled
along the Kansas/Oklahoma state line may push into northern
Oklahoma between 06-12Z shifting winds out of the north behind it.
However, surface winds will likely be more chaotic/variable in
direction and gusty across most of our terminals due to outflow
boundaries which will likely form due to the storm activity. There
is a low-level jet increasing out of the south through 12Z which
may impact terminals east of the storm activity at that time
mainly east and south of the I-44 corridor where non-convective
low-level wind shear is possible.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  72  82  68  77 /  40  80 100  90
Hobart OK         70  81  66  75 /  70  90 100  80
Wichita Falls TX  74  89  70  79 /  30  70  80  90
Gage OK           65  76  59  70 /  70  90  80  30
Ponca City OK     69  78  65  76 /  70 100 100  90
Durant OK         75  90  70  86 /  10  30  30  30

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Flood Watch from 7 AM CDT Wednesday through Thursday afternoon
     for OKZ005>029-033>038.

TX...Flood Watch from 7 AM CDT Wednesday through Thursday afternoon
     for TXZ083>085-087-088.

&&

$$

NEAR TERM...04
SHORT TERM...04
LONG TERM....13
AVIATION...68