853
FXUS64 KOUN 111758
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
1258 PM CDT Fri Jul 11 2025

...New NEAR TERM, SHORT TERM, HYDROLOGY...

.KEY MESSAGES...
Updated at 1256 PM CDT Fri Jul 11 2025

 - Increasing risk for thunderstorms with heavy rainfall and
   localized flooding beginning overnight tonight and continuing
   into the weekend.

 - Some severe weather possible overnight and Saturday with the
   primary threat of wind.

 - Another hot and humid day today with cooler-than-normal
   conditions expected this weekend.

&&

.NEAR TERM...
(Rest of today and tonight)
Issued at 1256 PM CDT Fri Jul 11 2025

A humid and wet weekend gets started this evening. It won`t be quite
as hot today as yesterday was. Guidance is indicating storm
development along a veered surface trough axis from north central
Oklahoma southwestward into the eastern Texas panhandle this
afternoon. Moderate instability (1,000-1,500 J/kg of MLCAPE) and
well-mixed boundary layers with dewpoint depressions around 30 will
foster at least some risk for severe downburst winds of 55-70 mph.
On the flip side, forecast soundings also suggest near-saturation in
the 3-9 km range AGL, which will limit DCAPE values around a maximum
of 1,300 J/kg. That saturation will also increase PWATS to near 1.8,
so thunderstorms today will be capable of rain rates of 2 inches per
hour (though storm size won`t be terribly large, which hopefully
limits the flooding risk).

The LLJ will increase modestly this evening. Despite that, there
could be a relative lull in storm coverage at times tonight. There`s
a pretty strong signal for a storm complex to move through the
panhandles toward southwest Oklahoma/western north Texas after
midnight. Most CAMS weaken this complex as it approaches, but MUCAPE
actually looks to increase along with the LLJ, so this could be a
candidate for "MCS that lasts longer than we think". Otherwise, the
synoptic-scale cold front will approach the Oklahoma/Kansas border
from the north toward the end of the overnight period, and storm
chances will increase along it near daybreak.

Meister&&

.SHORT TERM...
(Saturday through Sunday night)
Issued at 1256 PM CDT Fri Jul 11 2025

The primary messages in the short-term are threefold:

1) Heavy rainfall will occur somewhere in our area this weekend,
though the exact location of any flooding may be rather sporadic.
2) Severe thunderstorms are also possible this weekend, though the
overall risk is marginal (level 1 of 5) both days.3) Temperatures
will be anomalously cool this weekend.

Let`s break down each point.

1) The hydro concerns for this weekend will be discussed below in
the "hydrology" section.

2) The severe risk is not expected to be particularly robust with
any one wave of storms this weekend. However, tomorrow afternoon
looks like the most favorable parameter space. Here we will see
sufficient instability (MLCAPE 1,500 - 2,500 J/kg) for deeper
thunderstorms to form and perhaps organize into a few clusters along
surging outflows. Given the tropical boundary layers and deep mid-
level saturation, typical Plains dry microburst processes will be
very inefficient. Therefore, the primary path to creating damaging
wind gusts will be through wet microburst processes. Pinpointing
which specific thunderstorms will be capable of those wet
microbursts will be difficult more than a few minutes ahead of time,
so it will be a bit of a game of whack-a-mole. With that said, a few
gusts in the 55-70 mph range are expected.

3) We would be remiss if we didn`t mention the high likelihood of
much-below-average temperatures this weekend. Absolute anomalies (10
degrees cooler than normal) don`t tell the story, because summer is
a time of year when standard deviations of high temperatures become
much lower. It`s not very common at all to have back-to-back days in
the mid-80s in mid-July. Hopefully there are some breaks in the rain
for you to enjoy it.

Meister

&&

.LONG TERM...
(Monday through Thursday)
Issued at 100 AM CDT Fri Jul 11 2025

Models are currently expecting this cut-off mid-level cyclone over
the area to start slowly drifting northeast on Monday. On Monday
it is still in close enough proximity to keep some storm chances,
but these chances are advertised to decrease as we get into
Tuesday. But it is hard to have strong confidence in this with
the lack of mid-level flow or anything specific to nudge the low
away from the area, so we will be watching the trends with this
over the following forecast cycles. After that, the models
disagree on the timing and placements over any waves that would
affect the area. The best chance of any precipitation will be in
the north with any waves moving across the Plains that reach far
enough south to help produce precipitation.

&&

.AVIATION...
(18Z TAFS)
Issued at 1219 PM CDT Fri Jul 11 2025

Our terminals will most likely remain in the VFR category through
the forecast period. Isolated high-based TSRA are possible
through 00Z although probabilities are too low at any one terminal
in the TAF. However after 00Z, probabilities increase 30% for
TSRA across northwest Oklahoma and increasing to the south and
east in time by 06-12Z. By 14Z TSRA probabilities are greater than
50% as TEMPOS are in place across some of our terminals. Although
much of this convection early on will be high-based in a VFR
category, the convection may become more surface-based by 15Z with
some of our terminals reducing to MVFR category due to lower
ceilings and reduced visibilities in rain. High pressure over the
southeastern U.S. will maintain southerly surface winds at 10
gusting to 20 kts across our terminals. A surface front will be
pushing into northwest Oklahoma by 12Z shifting surface winds more
northerly behind the front.

&&

.HYDROLOGY...
Issued at 1256 PM CDT Fri Jul 11 2025

Storms could be ongoing as early as daybreak tomorrow across
northern Oklahoma. Over the next 36 hours, the synoptic front is
expected to drift southward across the area before stalling in the
vicinity of the Red River. This will lead to a rather low-
predictability flood risk with the potential for multiple axes of
higher QPF embedded within the background of a decent rain event.

Hopefully the activity tomorrow morning doesn`t stall out too much
in northern Oklahoma - it does seem as though there will likely be
upscale growth and propagation southward with that complex during
the morning. The round of storms that develops tomorrow afternoon
could be one of particular concern for flooding - especially if the
overnight complex coming east from the panhandle leaves behind an
MCV, which guidance suggests is probable. Weak deep-layer shear and
PWATS approaching 2 inches will make for very efficient warm rain
processes in an environment with 1,500-2,500 J/kg of MLCAPE.

Right now, it looks like the greatest flood risk tomorrow afternoon
and evening will be near I-40, including the OKC metro. HREF
ensemble probabilities with a 25 km neighborhood radius are 50-90
percent for 2 or more inches of rain. Practically speaking, that
doesn`t mean your house has a 50-90 percent chance of seeing 2 or
more inches of rain, but it does mean that somewhere in your county
has that chance. Perhaps of slightly greater concern is that those
same neighborhood probabilities for 4 or more inches of rain sit at
30-50 percent from the west OKC Metro through the east OKC Metro.

The current expectation is that outflow will push the zone of
greatest storm chances southward toward the Red River Saturday night
and Sunday morning. Uncertainty is much greater here because we
don`t know how far the boundary/front will push. However, the signal
on some members of the HREF (which suggest a swath of 2-4 inches of
rain is possible in southern Oklahoma through Sunday morning, with
the chance for another round Sunday afternoon) is worth paying very
close attention to.

Meister

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  73  85  69  84 /  20  70  50  50
Hobart OK         72  88  67  87 /  30  70  60  30
Wichita Falls TX  74  89  70  87 /  10  70  60  50
Gage OK           67  82  64  85 /  50  70  30  10
Ponca City OK     70  85  69  83 /  40  60  40  40
Durant OK         75  92  73  88 /  10  50  50  60

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Flood Watch from midnight CDT tonight through Saturday morning
     for OKZ008-009-012>048-050>052.

TX...Flood Watch from midnight CDT tonight through Saturday morning
     for TXZ086-089-090.

&&

$$

NEAR TERM...04
SHORT TERM...04
LONG TERM....26
AVIATION...68