285 
FXUS64 KOUN 230306 CCA
AFDOUN

Area Forecast Discussion...corrected...
National Weather Service Norman OK 
1003 PM CDT Thu Oct 22 2020

...New UPDATE...

.UPDATE...
Issued at 958 PM CDT Thu Oct 22 2020

Storms southwest have developed more than the models expected and
will likely persist for a while this evening yet. Have increased
POPs ahead of these storms and shifted to areal coverage wording.
Adjusted POPs for expected activity near the front farther
northeast as well and shifted toward areal coverage wording in
many of these areas as well.

While winds have been gusty behind the front, winds have not been 
gusting up to advisory criteria, so we are cancelling the wind 
advisory a little early.

&&

.SHORT TERM...
(This evening through Friday)
Issued at 217 PM CDT Thu Oct 22 2020

In response to the trough now crossing the northern Rockies,
surface lee trough and gradient have increased across our area
resulting in strong southerly winds. The strongest winds have 
been where momentum transfer has been maximized across northern 
Oklahoma and model forecast soundings suggest this will maintain 
but likely not increase in magnitude much through the afternoon. 
Elsewhere, gusts of 30-40 mph will continue until evening when we 
decouple slightly and speeds decrease some. 

A cold front extending through central into southeast Kansas will
accelerate into our area, in response to the aforementioned 
trough. 7-10-mb 3-hr pressure rises behind should result in 
sustained 20-30 mph winds with gusts near 40 mph across roughly 
the western half of the area later tonight. Plans are to 
evaluation trends and expand the current Wind Advisory as needed, 
but it currently looks like we should fall short of criteria 
(sustained 30-39 mph, and/or frequent gusts over 40 mph).

These surging cold fronts with warm capping elevated mixed layer 
can struggle to produce convection and are sensitive to small 
variations in cap strength and moisture depth. Some convection may
form along the front and quickly become undercut leading to a
anafrontal band of mostly weak convection. Greatest coverage
should be across east-central and southeast portions of the area,
generally from near OKC metro southeastward. This is when
forcing for ascent from eastward-moving shortwave perturbation now
over New Mexico will enhance convective potential and coverage.
Later in the night as ceilings lower, some drizzle may occur and 
last through early morning. 

Post-frontal northerly winds will gradually subside through the
day tomorrow. Temperatures at most locations may struggle to reach
50F. 

BRB

&&

.LONG TERM...
(Friday night through next Wednesday)
Issued at 408 PM CDT Thu Oct 22 2020

Temperatures will continue to decrease behind the cold front Friday 
night into Saturday, with freezing temperatures possible in portions 
of far northwestern Oklahoma. Surface winds will begin to shift out 
of the south on Saturday, which will start a brief period of 
temperature increases during the first half of the weekend. Highs 
should recover into the 50s and 60s for Saturday. 

The big story continues to be the following cold front which will 
begin moving into northwest Oklahoma Sunday morning, and push 
through the region on Sunday. Models continue to be in agreement on 
the general pattern of the upper-level longwave trough digging 
southward and developing a closed upper-level cyclone and a 
positively tilted trough through the region. Cold and below freezing 
temperatures will move in Sunday night across most of northern, 
central, and western Oklahoma, and bring Monday highs only into the 
30s and 40s. The below freezing lows will become more widespread 
Monday and Tuesday night, covering most of the region except for far 
southeastern Oklahoma.

Precipitation is becoming an increasing concern early next week, 
with quickly plummeting temperatures and the possibility for 
winter precipitation Monday through Wednesday. Isentropic ascent 
as well as shortwave troughs ejected ahead of the long-wave 
cyclone will produce widespread rain chances Monday, however any 
wintry precipitation will likely remain in northwestern Oklahoma 
with the colder temperatures. The winter precipitation chances 
will expand to the southeast as the cold airmass continues to 
establish itself in the area. As the upper-level cyclone 
approaches, precipitation will be more synoptically forced, and 
result in some wrap around precipitation as well.

For the type of winter precipitation, a large layer around 700mb 
will likely have temperatures well above freezing outside of the 
base of the long-wave trough, and will result in possible widespread 
areas of freezing rain. Any snow chances will likely be constrained 
near the time the upper-level cyclone pushes through the area and 
the entire atmospheric column cools below freezing.

The one big uncertainty continues to be the timing of when the upper-
level cyclone closes off and progresses through the region. The GFS 
continues to be more progressive and moves through the region 
Wednesday into Thursday, while the ECMWF closes off the low further 
west and makes it through the region. This will impact the timing
of the precipitation as well as the possible precipitation typing
with the 700mb colder air being associated with the trough. With 
large possible changes associated with the evolution of the upper-
level cyclone, we'll be watching closely how this long-wave trough
develops.

Zwink

&&

.AVIATION...
(00Z TAFS)
Issued at 644 PM CDT Thu Oct 22 2020

The cold front is moving into far northwestern Oklahoma at this 
time and will move through KWWR in about an hour. Stratus with 
MVFR and patchy IFR ceilings will start moving in behind the 
front. Although there are small isolated showers currently in 
north central Oklahoma and western north Texas, the higher chances
of showers will occur near and just north of the front.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  41  47  35  57 /  50  20   0   0 
Hobart OK         41  52  33  59 /  20  10   0   0 
Wichita Falls TX  45  49  38  60 /  40  20   0   0 
Gage OK           34  49  27  61 /  20   0   0   0 
Ponca City OK     41  49  33  54 /  60  20   0   0 
Durant OK         53  57  43  60 /  60  60   0   0 

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&

$$

SHORT TERM...12
LONG TERM....50
AVIATION...26

corrected to add removal of wind advisory.