Area Forecast Discussion
Issued by NWS Oklahoma City, OK

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FXUS64 KOUN 250349
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
949 PM CST Fri Nov 24 2017

.DISCUSSION...


&&

.AVIATION...
VFR conditions are expected through the daytime Saturday. A cold
front will pass north to south tonight bringing north winds.
Gusts are expected over the southwest quarter of OK on Saturday,
but winds everywhere will become light after sunset.


&&


PREV DISCUSSION... /issued 154 PM CST Fri Nov 24 2017/

DISCUSSION...
The primary focus continues to be on fire weather (see fire weather
section below for details). Otherwise, one low-end precipitation
event is possible late Tuesday through Tuesday night. We`ll see some
day to day variation in temperature with a few anomalously warm
days.

On the synoptic scale, a broad/deepening trough will build across
the eastern half of the country while mean ridging persists in the
west. In this pattern, northwesterly flow will continue and
strengthen across our region. As the mid-upper trough moves east, it
will force a cold front through this evening and tonight. Gusty
southerly winds this afternoon will subside somewhat before becoming
northerly behind the front and increasing later this
evening/tonight. No precipitation is expected.

Post frontal air mass will be cooler. Saturday`s temperatures are
expected to be about 10 to 15 degrees cooler than today`s. Eastward
shifting ridge and return of west-southwesterly mean low level flow
will support anomalous warmth again Sunday, especially in the west
where low 70s will be common for highs.

On Monday, 850 hPa trajectories from the San Andres/Sacramento
Mountain region and across the Llano Estacado into our area will
support quite an anomalous warm/dry plume to mix into. Furthermore,
strengthening mass response to deepening trough over the Great Basin
further supports the warm, dry, windy pattern. We didn`t hesitate to
use the warmer statistical guidance to assign temperatures for
Monday and near record/record high temperatures across western
Oklahoma seem probable. The orientation of the trough and
amplification of the preceding mean ridging generally doesn`t
support extensive cirrus over the area, so forecast confidence is
fairly high.

Moisture return Tuesday isn`t robust but sufficient when combined
with forcing for ascent from trough to result in some rain showers.
We added isolated thunderstorms for northeast portions of the area
during the evening given mid-level cooling supporting very meager
instability. Activity should shift east by Wednesday morning, unless
significant slowing in models occurs.

We deviated significantly from the blends at the end of the weak
given the influence of GFS on PoP fields. Several GFS ensembles do
not support the deterministic`s depiction of a positively tilted
trough and rain chances across the area. ECMWF is completely out of
phase, and so we discarded GFS as an outlier at this time, and went
with the ECMWF and EPS/GEFS ensemble mean which has ridging and dry
conditions over the area.

BRB

FIRE WEATHER...
Low RH and modest south-southwest breezes in combination with ERC
values approaching the 75th percentile are supporting elevated
fire weather conditions across mainly southwest Oklahoma and
western north Texas this afternoon. For any ongoing fires into the
evening, area fire managers need to be aware of a wind shift with
a cold front that will progress from northern Oklahoma early this
evening through the rest of the area into the night.

Breezy north winds and lowest RH behind the front tomorrow should
be misaligned for a more significant fire weather concern.
Elevated conditions probably won`t be met.

Despite a dry air mass and warm temperatures Sunday, winds should
be fairly light precluding a more widespread fire threat.

Monday is the greatest day of concern for the next several.
Anomalous warmth, similar to today, and mixing/drying, along with
dry/dormant fuels will support widespread elevated fire weather
conditions across all of western Oklahoma and portions of central
Oklahoma and western north Texas.

BRB

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  49  63  37  68 /   0   0   0   0
Hobart OK         48  65  36  68 /   0   0   0   0
Wichita Falls TX  48  68  36  69 /   0   0   0   0
Gage OK           40  62  35  73 /   0   0   0   0
Ponca City OK     46  62  36  68 /   0   0   0   0
Durant OK         45  69  39  69 /   0   0   0   0

&&

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

$$

11/09/09



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