Area Forecast Discussion
Issued by NWS Amarillo, TX

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FXUS64 KAMA 221749 AAB

Area Forecast Discussion...UPDATED
National Weather Service Amarillo TX
1249 PM CDT Thu Mar 22 2018

For the 18Z TAFs, Winds will gradually become southwest late
tonight, then increase in speed and become gusty by mid morning
Friday as the pressure gradient tightens. Periods of high level
clouds are also expected through late Friday morning.



.PREV DISCUSSION... /Issued 613 AM CDT Thu Mar 22 2018/

For the 12z TAFs...
VFR forecast continues next 24 hours.  Low-level wind shear is
forecast at AMA through 15z as low-level jet sampled by KAMA 88D
remains in place.  Otherwise, no clouds below 10,000 feet are
expected.  No strong winds are expected.


PREV DISCUSSION... /Issued 504 AM CDT Thu Mar 22 2018/

Forecast is still on track for a nice day today followed by
another critical to extremely critical fire weather day on
Friday. Latest upper level analysis indicates yet another
northeaster moving up the north Atlantic coast. Meanwhile a ridge
of high pressure currently centered over the Rockies continues to
gradually shift eastward as the jet streak of a shortwave trough
approaches the southern CA coast.

The mid/upper level ridge axis will shift over the Panhandles
today helping the area warm well above average with highs in the
low to mid 80s. Winds should stay light to breezy with the
strongest pressure gradient being across the eastern zones this
afternoon as surface high pressure shifts into the LA/MS region.

The mid/upper ridge breaks down on Friday as the aforementioned
shortwave trough advances over the Rockies. Statistical and
deterministic guidance generally agrees that 50-75 knot 500mb
winds will overspread the Panhandles by early afternoon with the
strongest winds over the northwestern zones by 21z. In response
to this shortwave jet dynamics, a surface low will develop in SE
CO and move into western KS. The combination of a strengthening
pressure gradient as the low deepens and ample mixing during the
day will result in windy conditions across most of the combined
Panhandles. The strongest downslope winds are expected on the
Caprock of the Texas Panhandle, where momentum transfer from
stronger winds aloft will be maximized. A High Wind Watch has been
issued starting late Friday morning through early evening for the
western Texas Panhandle. Winds as strong as 40mph gusting to
60mph will be possible in the watch area. The main caveat is the
possibility for some mid-level cloud cover at the top of the BL in
the afternoon Friday which could affect mixing potential.
Otherwise, expect near Summer like conditions with highs in the
mid 80s (west) to low 90s (east) as the downslope winds help mix
down 21-24 deg C 850mb temps during the afternoon. Fire weather
will of course be a major concern Friday (see details below).

A front will move through the Panhandles Friday evening and
overnight switching winds from the west to the northwest. Based
on the current track of the surface low and the lack of strong
synoptic forcing or cold air advection, the winds behind the front
are not expected to be nearly as strong as some of our more
recent fronts. Highs on Saturday will be cooler than Friday, but
still about 10 degrees above average as highs top out in the mid
70s to low 80s and light to breezy winds.

Another very warm and breezy to windy day can be expected Sunday
as mid/upper high pressure becomes established over the Gulf of
Mexico and an upper trough digs into the western CONUS, increasing
southwesterly winds aloft. The real interesting model data starts
showing up going into next week, especially the middle of next
week when the upper trough is being advertised centered over
southeastern New Mexico, possibly as a closed low. Of course, the
guidance (especially the GFS) has teased similar patterns before,
and progressive flow verified keeping the area dry. However, it is
hopeful to see some model to model consistency and run to run
consistency with some precipitation looking possible especially by
Tues/Wed. Not only that, but cooler temperatures due to at least a
modest cold front can also be expected in this time-frame. And
last but not least, if everything aligns right, snow can`t be
ruled out for the northwestern zones Tuesday night and Wednesday
morning behind the front.



A critical to extremely critical fire weather day is expected
once again on Friday as a shortwave and attendant jet streak help
break down ridge over area. Ample mixing will allow strong
downslope winds, especially for the western Texas and Oklahoma
Panhandles where southwest-west winds could gusts upwards of 50
to 60 mph. The dry downslope winds combined with temperatures in
the mid 80s will result in min RH values around 10 percent for all
of the Panhandles. There is some question to the position of a
dryline in the eastern Panhandles (which is currently expected to
shift well east of our area by afternoon Friday). Thus. the Fire
Weather Watch has been continued for the eastern Panhandles where
there is still some uncertainty with the dryline. The Fire
Weather Watch has been upgraded to a Red Flag Warning for the
western TX/OK Panhandles where confidence is highest that
conditions will be met. RFTI values will be around 4-6 across most
of the area given current wind/RH in the forecast. Fuels remain
very dry as of this forecast (80th-90th ERC percentile). A front
will shift through the area Friday evening and overnight, shifting
winds to the northwest at 15-25 mph.

Spotty elevated fire weather conditions are possible Saturday,
mainly for the western Panhandles.

Elevated to critical fire weather conditions are expected Sunday
and Monday, with the worst conditions expected over the western



.AMA Watches/Warnings/Advisories...
TX...Fire Weather Watch from Friday afternoon through Friday evening
     for the following zones: Collingsworth...Donley...Gray...

     Red Flag Warning from noon to 9 PM CDT Friday for the following
     zones: Armstrong...Carson...Dallam...Deaf Smith...

     High Wind Watch from Friday morning through Friday evening for
     the following zones: Dallam...Deaf Smith...Hartley...

OK...Fire Weather Watch from Friday afternoon through Friday evening
     for the following zones: Beaver.

     Red Flag Warning from noon to 9 PM CDT Friday for the following
     zones: Cimarron...Texas.


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