129
FXUS64 KOUN 050337
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
937 PM CST Wed Dec 4 2024

...New UPDATE, AVIATION...

.KEY MESSAGES...
Updated at 937 PM CST Wed Dec 4 2024

- Areas of dense fog overnight in south central and southeastern
  Oklahoma and portions of north central Texas.

- Seasonable temperatures through the week with modest day to day
variations.

- Low rain chances across the southeast on Wednesday; low rain
  chances across the south Friday night into the weekend.

&&

.UPDATE...
Issued at 937 PM CST Wed Dec 4 2024

A Dense Fog Advisory has been issued for south central and
southeast Oklahoma and Clay County of north Texas.

The cold front has slowed it`s progress this evening, especially
across southeastern Oklahoma where winds are weak north of the
front so little advection is occurring. Satellite has shown the
low-level moisture creeping northward near the frontal boundary.
Dense fog has developed in Ardmore and Ada thanks to the light
winds near the front and where drier air had not moved in.

Models suggest that the fog will erode overnight from north to
south as the front and drier air slowly move south, which sounds
good in theory. But would like to see evidence of this push south
before getting too tricky with the timing of the fog for the
advisory, so have issued the advisory through 13Z (7 AM CST).
Northern portions of the advisory may be able to be cancelled
early if the dry air does start to filter in.

&&

.NEAR TERM...
(Rest of today and tonight)
Issued at 248 PM CST Wed Dec 4 2024

A vertically stacked synoptic system moving across the U.S. Great
Lakes will continue to push a cold front across our area through
this evening.  Currently the leading edge/wind shift of the frontal
boundary had already reached the I-44 corridor.  A colder Canadian-
based airmass lagging behind the front will slowly start coming
through tonight with subfreezing temperatures across northern &
western Oklahoma to mid to upper 30s across the remainder of our
area. Northeast winds around 10 mph will produce wind chills values
making it feel well in the 20s areawide early Thursday morning.

&&

.SHORT TERM...
(Thursday through Friday night)
Issued at 248 PM CST Wed Dec 4 2024

A split-flow pattern will persist in the upper levels with a cold
trough in the jet stream digging across the eastern half of the
country and a cut-off low system stalled over the Southwestern U.S.
The Southern Plains will generally lie between both systems but will
remain more influenced on Thursday by the colder air coming down
through the trough.  We`ll see below normal temperatures on Thursday
afternoon mostly in the 40s to lower 50s near and south of the Red
River and not much sunshine under increasing high cloudiness.
Temperatures drop rapidly after sundown as northeast winds go light
and variable setting up a night of strong radiational cooling with
our entire forecast area expected to go subfreezing (20s).

Upper ridging east of the cut-off system will start building across
the Southern Plains on Friday.  With the surface high settling
across the Mississippi Delta Region, we`ll see a shifting of south
winds starting a warming trend under the building ridge with highs
warming into the 50s for Friday afternoon.  Southerly flow may
increase moisture transport across the Southern Plains with warm
advection in stable air increasing rainfall chances Friday evening
and overnight just north of the Red River.  Guidance showing fairly
strong isentropic upglide in the mid-levels with some additional mid-
level shortwave energy being expelled through the ridge.  Will
maintain low (20-30%) rain POPs across our western north Texas
counties for Friday evening and shifting them to our southcentral &
southeast Oklahoma counties for overnight.  Not expecting any frozen
precipitation Friday night but a "cold rain" across our south with
temperatures staying above freezing (mid to upper 30s) overnight.

&&

.LONG TERM...
(Saturday through Tuesday)
Issued at 246 AM CST Wed Dec 4 2024

Deterministic and ensemble models are starting to show some more
agreement on how to handle the cutoff low spinning over the
southwest U.S., bringing it up through the central plains on Sunday.

As far as sensible weather, nearly all ensemble solutions suggest a
warming trend through the weekend with temperatures peaking in the
60s on Sunday. Low rain chances (20-40%) will also return to
southern parts of the forecast area over the weekend.

Another cool down is then forecast with our next front sometime
early next week, though models are exhibiting typical levels of
disagreement from this range regarding the timing and amplitude of
this next trough.

Day/Ware

&&

.AVIATION...
(Update and 06Z TAFS)
Issued at 937 PM CST Wed Dec 4 2024

The front has stalled out and so it will likely be longer until
drier air moves into KDUA and clears out the stratus and fog. With
this, have amended the KDUA TAF to keep IFR conditions in longer
tonight.

Some fog has been reported in social media in the vicinity of
Wichita Falls, but KSPS is on the north side of the moisture
gradient and has a lower humidity than KCWC on the south side of
Wichita Falls. With this drier air at KSPS and a north wind at 6
knots bringing in even drier air, the potential for fog (or
stratus) appears to be low, but there may be some not very far
southeast of KSPS for a while tonight.

Eventually, the cold front and drier air will continue to spread
south and erode the fog and stratus across southern Oklahoma and
north Texas (including KDUA), but it may be a little slower than
some of the models suggest.

Farther north, we expect VFR conditions. There are some
observations of low visibility (including KRCE and KEND at the
moment), but the low humidity suggests that these low visibilities
are likely either sensor issues or perhaps spider webs.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  33  43  25  50 /   0   0   0   0
Hobart OK         34  48  26  50 /   0   0   0   0
Wichita Falls TX  38  52  29  52 /   0   0   0  10
Gage OK           27  45  26  59 /   0   0   0   0
Ponca City OK     27  39  22  49 /   0   0   0   0
Durant OK         39  50  27  49 /   0   0   0   0

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Dense Fog Advisory until 7 AM CST Thursday for OKZ032-040>043-
     045>048-050>052.

TX...Dense Fog Advisory until 7 AM CST Thursday for TXZ090.

&&

$$

NEAR TERM...68
SHORT TERM...68
LONG TERM....14
AVIATION...26