Area Forecast Discussion
Issued by NWS Oklahoma City, OK

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FXUS64 KOUN 301518

Area Forecast Discussion
National Weather Service Norman OK
918 AM CST Wed Nov 30 2016

Adjusted temperatures and wind.


A decent short wave trough continues to exit the southern plains
to the east this morning. In its wake, surface high pressure
continues to evolve over the southern plains. In tandem with
northwest flow on the back side of the larger parent trough, a
noticable pressure gradient continues to develop this morning into
northern Oklahoma. With this subtle trend, increased wind speeds a
few knots in magnitude through the mid afternoon across northern
Oklahoma. Additionally, tapered back temperatures as obs trends
from sunrise through 9 AM CST showed a marked slower warming
trend, and from latest Mesonet observations, this trend seemed
warranted but did not make any major changes to afternoon highs
from the night shift.



.PREV DISCUSSION... /issued 530 AM CST Wed Nov 30 2016/

The November 30-December 1, 2016 12 UTC TAF discussion follows:

VFR conditions will continue through the TAF period.
Northwesterly winds may gust to 20 knots across central/northern
Oklahoma by late morning into the early afternoon. Winds should
weaken by this evening and become light from the south. A
northerly wind shift will pass by the northern terminals
(KGAG/KWWR/KPNC) toward the end of the period. Wind speeds are
expected to be less than 5 knots by then.


PREV DISCUSSION... /issued 342 AM CST Wed Nov 30 2016/

The primary forecast concerns are the chance/type of
precipitation for the weekend and then the potential for a
significantly colder airmass by the middle of next week.

For today, cold air advection from breezy northwest winds will
allow for a slightly cooler, but seasonable day. As the surface
ridge settles in tonight, the combination of light winds, clear
skies, and a dry airmass will provide an excellent environment for
radiational cooling. Expect many locations to drop to at least
freezing, with a hard freeze likely across northern Oklahoma.
Temperatures will warm back to above average by Thursday
afternoon with a return to southerly winds.

By late Friday into Saturday, increasing isentropic ascent/warm
air advection will result in widespread rain. The greatest ascent
will begin across western north Texas/southwest Oklahoma late
Friday and spread eastward Friday night into Saturday. Rain
chances will increase with southward extent during the day

Opted to raise low temperatures Saturday morning based on warmer
deterministic surface and wetbulb temperatures from the 30/00Z
NAM/GFS/ECMWF. Though a brief period of snow/rain mixture is
possible across far northwest Oklahoma early Saturday morning,
any impacts look minimal as any subfreezing temperatures are
expected to quickly wetbulb to above freezing. For most
locations, it will a cold rain on Saturday. Went colder than
blended guidance Saturday afternoon as the abundant cloud cover
and rain should keep temperatures in the 40s all day.

Lingering rain will be possible on Sunday, especially across
eastern Oklahoma. There continues to be uncertainty on when the
upper low will eject and lift northeastward. Therefore, still have
a low chance of rain on Monday, especially across the southeast.

By the middle part of next week, there are indications in all the
global models that the coldest air of the season will impact a
large part of the country, including the Southern Plains. The
uncertainty is the timing of the cold air. The 30/00Z ECMWF is
faster with the front than the 30/00Z GFS. For now, trended cooler
across the northwest Tuesday. If the cold front passes by during
the day Tuesday, would expect falling temperatures in its wake;
however, it`s too early for specifics a week out. Nevertheless, a
significant cool-down appears likely by next Wednesday at the



Oklahoma City OK  55  30  60  34 /   0   0   0   0
Hobart OK         55  30  57  31 /   0   0   0   0
Wichita Falls TX  57  34  62  38 /   0   0   0   0
Gage OK           53  23  53  24 /   0   0   0   0
Ponca City OK     52  26  56  29 /   0   0   0   0
Durant OK         57  35  62  40 /   0   0   0   0




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