Area Forecast Discussion
Issued by NWS Oklahoma City, OK

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FXUS64 KOUN 291726

Area Forecast Discussion
National Weather Service Norman OK
1126 AM CST Tue Nov 29 2016



.AVIATION... /For the 18z TAFs/
A cold front has moved through all TAF sites except Wichita Falls,
and north-northwesterly winds are occurring across the area. Winds
should veer to north-northwesterly at Wichita Falls by 19z. Speeds
will decrease around sunset. VFR conditions will prevail.


.PREV DISCUSSION... /issued 1049 AM CST Tue Nov 29 2016/

Increased surface winds today. Also, increased afternoon highs a
few degrees southeast of I-44. Adjusted sky cover today as well.

Dry and breezy conditions with slightly above average surface
temperatures and abundant sunshine will occur this afternoon.

Surface winds have increased quickly this morning as a result of
steep low level lapse rates and deep vertical mixing for this
time of year. Thus, increased them.

Surface temperatures have increased quicker than previously
forecast near and south of a weak surface cold front/wind shift
that existed near a Wichita Falls to Ada line as of 1045 am.
Thus, raised highs in these areas.

Products will be updated shortly.


PREV DISCUSSION... /issued 352 AM CST Tue Nov 29 2016/

Overall, a quiet weather pattern is expected for the next few
days. Primary forecast concern is the chance/type of
precipitation for the upcoming weekend.

For today, a dry cold frontal passage will pass by from northwest
to southeast. This will cool temperatures slightly; however, still
expect highs above average for late November. Low-level cold air
advection will bring in even cooler (though seasonable) weather
for tomorrow.

By tomorrow night, the surface ridge is expected to be centered
across the Southern Plains. Light winds, clear skies, and a dry
airmass will provide an excellent environment for radiational
cooling. Expect most locations to drop to at least freezing, with
a hard freeze likely north of I-40. Temperatures will moderate
slightly by Thursday afternoon with a return to southerly winds.

On Friday, another dry cold frontal passage is expected at least
across the northern half of Oklahoma. Only expect slightly cooler
temperatures Friday afternoon

For the weekend, confidence has increased for less wintry
precipitation and more of a cold rain across the area. The 29/00Z
ECMWF has trended toward a warmer/slower closed-low, which is in
better agreement with the other global models. Still expect
isentropic ascent to result in widespread rain, especially south
of I-40, starting late Friday into Saturday.

Opted to increase low temperatures both Saturday and Sunday
morning based on a warming trend in the deterministic raw
temperatures. Consequently, kept a mention of rain/snow mixture
across the northwest/northern Oklahoma, where temperatures are
forecast to be close to freezing. The top-down method would
suggest sleet and/or freezing rain might be possible (rather than
snow); however, opted to keep it simple for now as the (possible)
transition zones will evolve as the event draws closer.

There is still some uncertainty on how quick the low will lift
northeastward. Therefore, kept low chance of precipitation even
into Monday; however, kept the highest chances of precipitation late
Friday into early Sunday, where forecast confidence is the



Oklahoma City OK  61  33  55  30 /   0   0   0   0
Hobart OK         59  31  55  29 /   0   0   0   0
Wichita Falls TX  64  35  57  33 /   0   0   0   0
Gage OK           56  28  53  22 /   0   0   0   0
Ponca City OK     60  30  53  26 /   0   0   0   0
Durant OK         70  38  57  35 /   0   0   0   0




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