Area Forecast Discussion
Issued by NWS Oklahoma City, OK

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FXUS64 KOUN 221624 AAA
AFDOUN

Area Forecast Discussion...UPDATED
National Weather Service Norman OK
1024 AM CST Wed Feb 22 2017

.UPDATE...
Increased highs this afternoon a few degrees in far western
Oklahoma and far western north Texas. Also, decreased surface
dewpoints slightly this afternoon in many areas.

&&

.DISCUSSION...
Warm and dry conditions with fairly light wind can be expected
this afternoon. Made the changes above based on model guidance
(mainly the HRRR) and latest surface observations.

Products will be updated shortly.

MBS

&&

.PREV DISCUSSION... /issued 541 AM CST Wed Feb 22 2017/

DISCUSSION...
The February 22-23, 2017 12 UTC TAF discussion follows:

AVIATION...
No ceiling or visibility restrictions are expected through the TAF
period. A northwesterly windshift will pass by western Oklahoma
later this morning. Any northerly winds will return to the south
by this evening. Elsewhere, winds will remain from the south
through the TAF period. Wind speeds will remain relatively light
(<12 knots) as well.

Mahale

PREV DISCUSSION... /issued 430 AM CST Wed Feb 22 2017/

DISCUSSION...
Primary forecast concern is fire weather conditions over the next
week.

For today, high temperatures are expected to be warmer than
yesterday as 850 mb temperatures are progged to be around 3C
warmer than yesterday`s 00Z sounding. A weak trough/northwesterly
wind shift is expected across the west; however, there will be no
temperature impacts associated with the boundary. Southerly winds
will return by tonight.

An intense, 85-knot mid-level jet is forecast to eject into the
Central Plains by Thursday afternoon. In response, significant
pressure falls are expected across central Kansas. As the surface
low tracks northeastward, a dryline will shift into western
Oklahoma Thursday afternoon.

Unseasonably warm temperatures are expected Thursday afternoon
with eastward propagation of a low-level thermal ridge. 850 mb
temperatures are progged to be around 17-21C. Based the Storm
Prediction Center Climatology Page (max moving average), these are
near or above the climatological maximum for 24 February at 00Z.
Consequently, temperatures are expected to warm into the 80Fs to
near 90F--around 30F above climatological averages.

NAM and GFS BUFR soundings indicate very deep mixing behind the
dryline (>800 mb), which may result in gusty winds >30 mph. Ahead
of the dryline, the mixing will not be as deep; however, the
winds above the surface are progged to be stronger (which appears
to be in response to a lead wave/mid-level jet streak). So gusty
winds will be possible even ahead of the dryline. These conditions
will result in critical fire weather conditions. Please see the
Fire Weather section below for more details.

By Thursday night, surface winds will veer to the northwest as a
cold front shifts southeastward. The airmass behind the front is
seasonably cool with near average temperatures forecast on
Friday. A widespread freeze is expected Friday night into Saturday
morning.

On Saturday, a secondary surge of low-level cold air advection will
result in below average temperatures Saturday afternoon; however,
by Sunday, southerly winds/warmer temperatures will return. A
weak cold front is progged to enter at least northern Oklahoma
Sunday night. There will also be a low chance of showers/storms
Sunday night. There is some uncertainty on how much cool air will
affect the area on Monday. The 22/00Z ECMWF is cooler than the
GFS, so forecast confidence on temperatures is lower for Monday.

On Tuesday, another significant mid/upper-level trough will
approach the Plains. In response, unseasonably warm temperatures
and gusty southerly winds are expected. An eastward dryline push
may result in critical fire weather conditions. There will also
be a chance of showers and thunderstorms as the dryline surges
east--primarily from I-35 eastward. Cooler weather is expected in
the system`s wake on Wednesday.

Mahale

Fire Weather...
For today, elevated fire weather conditions are expected across
western Oklahoma and far western north Texas. Temperatures will be
20-25F above average with minimum relative humidity values
15-20%. ERC-G values will be just above the 50th percentile. The
limiting factor for a Red Flag Warning will be wind speeds. A
weak northwesterly wind shift/trough that will pass by late this
morning will result in relatively light wind speeds (5-10 mph with
gusts to 15 mph).

Critical to extreme fire weather conditions are expected Thursday
afternoon across western Oklahoma and adjacent parts of north
Texas. A dryline will move into western Oklahoma in response to
an intense mid/upper level trough approaching the Plains. Winds
will veer to the west-southwest as the dryline passes by and deep
mixing will allow for sustained wind speeds at 20 to 25 mph with
gusts to 40 mph. Temperatures are forecast to warm into the 80Fs
to near 90F--around 30F above climatological averages. Very low
relative humidity values (~10%) will be possible near the 100th
meridian.

A cold front will pass by Thursday night, which will result in
winds veering to the northwest. Though cooler air is expected,
gusty northwest winds will maintain at least elevated fire weather
conditions on Friday--especially across northern Oklahoma (where
the strongest winds are forecast) and parts of western north
Texas (where the warmest temperatures are forecast).

Near-critical to critical fire weather conditions are possible
next Tuesday as another intense mid/upper level trough
approaches the Plains. This trough may push another dryline
eastward into western Oklahoma and parts of western north Texas.

Mahale

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  78  50  81  42 /   0   0   0   0
Hobart OK         78  48  83  39 /   0   0   0   0
Wichita Falls TX  82  50  86  44 /   0   0   0   0
Gage OK           83  47  80  32 /   0   0   0   0
Ponca City OK     78  48  80  39 /   0   0   0   0
Durant OK         79  51  81  51 /   0   0   0   0

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Fire Weather Watch from Thursday morning through Thursday
     evening for OKZ004-005-009-010-014>016-021-022-033>037.

TX...Fire Weather Watch from Thursday morning through Thursday
     evening for TXZ083>085-087-088.

&&

$$

17/23



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