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Area Forecast Discussion (AFD)

Issued by Norman, OK (OUN)

                            
000
FXUS64 KOUN 212131
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
331 PM CST Thu Feb 21 2019

.DISCUSSION...
Active weather will commence tonight as lower level moisture 
increases and results in an increase for drizzle/fog and scattered 
showers overnight through much of Friday. As strong upper storm 
approaches late in the day, thunderstorm chances will also begin to 
increase by evening and especially overnight through early Saturday. 
While a majority of any convection is expected to be elevated in 
nature, a few strong to severe storms appear possible toward 
daybreak Saturday across far southeast portions of Oklahoma as 
dryline pushes quickly east. Damaging winds would be the primary 
severe weather concern if near surface based storms can develop this 
far west.

As upper low takes shape and strong cyclogenesis takes place near
the Kansas border on Saturday, very strong winds will be seen 
over a large part of the Southern Plains. The strongest winds are 
expected over western Texas into northern Texas and southwest 
Oklahoma late Saturday morning and afternoon where deeper mixing 
will occur behind dryline. In this area, 50 to 60 mph wind gusts 
and sustained winds around 40 mph appear likely. A High Wind Watch
will be issued covering a large part of western north Texas and 
southwest/western Oklahoma. Farther east, a Wind Advisory will 
likely be needed. Some of the watch may be transitioned to an 
advisory with High Wind Warning most likely across western north 
Texas and southwest Oklahoma. 

With the strong pressure gradient, we will see strong cold air 
advection behind a cold front on Saturday. This cold air will likely 
become deep enough for a transition to snow across northwest 
Oklahoma Saturday afternoon. This time period will also coincide 
with passage of deep/cold mid-level trough which is trending farther 
south each in each run of all models except the GFS/GFSfv3. This 
time window for snow will be very short, but enough snow could occur 
near the Kansas border to create brief blizzard conditions Saturday 
afternoon. By Saturday evening, the lower level pressure gradient 
quickly weakens and decoupling will allow a quick and significant 
decrease in winds for Saturday night.

Elevated fire weather conditions will also be seen across
southwest Oklahoma, with near-critical conditions forecast across
much of western north Texas. ERC-G values and recent precipitation
will be the limiting factors for higher level fire weather
conditions farther north and east.

Farther out, through next week, little in the way of changes were
made to going forecast as medium range models continue to show
differences in timing and intensity of cold air intrusions.
Consensus approach would increase confidence in stronger cold air
push for latter half of next week. Some light precipitation cannot
be ruled out around Thursday, but model inconsistency and low
confidence will preclude mention.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  39  49  44  57 /  10  20  60  60 
Hobart OK         38  50  43  57 /  10  20  60  30 
Wichita Falls TX  39  54  47  63 /  20  20  60  20 
Gage OK           35  47  40  46 /  10  20  70  70 
Ponca City OK     35  47  43  55 /  10  20  40  80 
Durant OK         42  52  47  63 /  30  40  60  70 

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...High Wind Watch from Saturday morning through Saturday afternoon 
     for OKZ021-022-033>038-044.

TX...High Wind Watch from Saturday morning through Saturday afternoon 
     for TXZ083>090.

&&

$$

14/11