818
FXUS64 KOUN 290703
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
203 AM CDT Tue Sep 29 2026

...New NEAR TERM, SHORT TERM, LONG TERM...

.KEY MESSAGES...
Updated at 158 AM CDT Tue Sep 29 2026

- Periods of heavy rain are expected from Tuesday afternoon
  through Thursday afternoon, with flooding possible in parts of
  western north Texas and southern Oklahoma.

- Chance of severe storms Wednesday afternoon and Wednesday night.

- Significant cooldown expected from Thursday through the weekend.

&&

.NEAR TERM...
(Through Tuesday)
Issued at 158 AM CDT Tue Sep 29 2026

We`ll feel the opening salvos of the upcoming rain event this
afternoon and evening. Chances for rain and thunderstorms today will
primarily be across the northern and western parts of Oklahoma that
have been favored for rain over the last week or so. The primary
impacts will be pockets of heavy rain and lightning. For the rest of
us, one final day of summer heat awaits.

Shortwave ridging remains in place early this morning across the
Southern Plains, but by midafternoon a lead wave will be ejecting
into Kansas from the southwest. This will push us into a broad zone
of southwest flow that corresponds to the tropical moisture plume.
About 1,000 J/kg of MLCAPE will exist by early afternoon, so
scattered to widespread small showers and thunderstorms are expected
to develop with the lead wave. Deep-layer shear will be quite weak,
so organization of individual storm cells into multicell clusters or
supercells is unlikely. PWATs will already be pushing/exceeding 2.00
inches with this activity, so potential for brief very heavy rain
rates will exist. The primary zone for this activity will be along
and north of a line from Sayre to Perry.

The lead wave will depart by late in the afternoon. The primary
trough and Polo`s remnants will still be well to our west. That
means that much of tonight looks dry across our area, potentially
excepting far western or northern Oklahoma closer to the moisture
conveyor. Temperatures continue to be quite warm with dewpoints
sitting as high as they are.

Meister

&&

.SHORT TERM...
(Tuesday night through Thursday night)
Issued at 158 AM CDT Tue Sep 29 2026

The primary window for active weather looks to be in the short-term
forecast period from Wednesday - Thursday. Heavy rainfall and
attendant flooding as well as severe weather are possible. The end
of the short-term period will see us making a transition into
something a little closer to fall.

0Z guidance tonight is surprisingly united in showing a period of
relatively dry weather Wednesday morning. This is potentially due to
the passage of the 700 mb warm front earlier in the morning. Either
way, this will allow classic cyclogenesis to occur in the lee of the
New Mexico Rockies. As the surface low sweeps northeast ahead of the
trough, the dryline will sharpen near the OK/TX panhandle border by
Wednesday afternoon. With height falls overspreading the dryline
late in the afternoon, this would look like a classic transition-
season severe weather event - if there was any semblance of an EML
whatsoever. As it is, warm advection during the daytime will lead to
the development of isolated showers in a 1,000 MLCAPE environment,
but the chances of discrete dryline convection seem rather slim.

The more robust opportunity for thunderstorms will occur in the
evening to overnight near and southeast of I-44. With the trough`s
approach continuing to lower heights, continued low-level theta-E
advection, and a 40 knot veered LLJ across the warm sector, there
are more than a few similarities synoptically between this event and
others that have produced prolifically rainy squall lines (and those
event did so with lower PWATS than we will see). How much rain falls
will largely be a question of the location and progressiveness of
the MCS. There is some reason to believe it won`t translate eastward
all that rapidly with meridional flow aloft and such a powerful LLJ.
In that case, parts of southern Oklahoma and western north Texas are
likely to see multiple inches of rain. NBM 90th percentile rainfall
totals are near 6 inches of rain by Thursday afternoon in a portion
of southern Oklahoma centered on Pauls Valley. While it is unlikely
that many locations receive up to 6 inches of rain, that benchmark
serves as a reasonable anchor to a mental model of what localized
flash flooding may look like Wednesday night. Severe weather is
possible with this MCS. The lack of EML will reduce instability
overall, but favorable theta-E advection regimes could increase low-
level instability. If so, hodographs Wednesday night would be
favorable for QLCS-embedded tornadoes.

It also needs to be said that the majority of 0Z guidance members
are bifurcating rain totals. In effect, the Tuesday/early Wednesday
wave of rain in northern/western Oklahoma and the stripe of heavier
rain from the Wednesday night MCS may not overlap, with a "Reverse
Goldilocks zone" of low-to-nil rainfall totals in between them
through Thursday. This is an extremely complex forecast and we are
not encouraging anyone to give up on their chance for a good,
soaking rain. But right now, a best estimate of where that reverse
Goldilocks zone might end up being would highlight west central
Oklahoma, southwest Oklahoma, and central Oklahoma as far southeast
as the western OKC metro.

The upper-level trough will approach and move overhead/through
Kansas during the day on Thursday. With the deeply saturated airmass
in place, redevelopment of storms in the warm sector remains a
possibility, particularly southeast of I-44. The backside of the
system will bring a robust cold front by Thursday night.

Meister


&&

.LONG TERM...
(Friday through Monday)
Issued at 158 AM CDT Tue Sep 29 2026

The story of the long-term forecast is one of a long-awaited pattern
change. Cooler temperatures are expected. Much drier weather will
occur in northern/western Oklahoma, while rain chances will linger
in southeast Oklahoma and parts of western north Texas.

As the trough responsible for this week`s system approaches the
polar jet, it will degenerate into an open wave. However, the
remnant weakness in the subtropical ridge (still kicking to our west
and east) will allow our weather to behave more like early October
should. The robust cold front on Thursday will keep sweeping through
on Friday, and a reinforcing front is expected early next week as a
1026 mb high dominates the central US. This will keep temperatures
at or below seasonal normals as late as next Monday before lee
troughing potentially returns.

Showers do linger in the forecast, particularly Friday and Saturday
in southeast/central Oklahoma where remnant moisture may be
stronger. The reinforcing front will do the job to dry us all the
way out: our forecast calls for no mentionable rain chances next
Monday.

Meister

&&

.AVIATION...
(00Z TAFS)
Issued at 937 PM CDT Mon Sep 28 2026

All terminals should remain in a VFR category through the forecast
period. There is a 30% probability for rain showers and a few
thunderstorms moving into western and across northern Oklahoma
between 16-00Z while could impact terminals KCSM, KWWR, KPNC and
could be near terminal KSWO. Otherwise south surface winds
increase by 15Z around 10 kts sustained with gusts between 15-20
kts. Surface winds should back slightly southeast after 00Z at
5-10 kts.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  91  73  85  69 /  30   0  60 100
Hobart OK         90  72  85  69 /  30  30  50  70
Wichita Falls TX  95  73  90  69 /  10  10  60 100
Gage OK           80  67  83  63 /  80  60  50  50
Ponca City OK     84  70  85  66 /  60  10  60 100
Durant OK         93  72  91  70 /   0   0  30  80

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Flood Watch from Wednesday afternoon through Thursday afternoon
     for OKZ031-032-040>043-045>048-050>052.

TX...Flood Watch from Wednesday afternoon through Thursday afternoon
     for TXZ086-088>090.

&&

$$

NEAR TERM...04
SHORT TERM...04
LONG TERM....04
AVIATION...77