Area Forecast Discussion
Issued by NWS Amarillo, TX

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177
FXUS64 KAMA 280123 AAA
AFDAMA

Area Forecast Discussion...UPDATED
National Weather Service Amarillo TX
823 PM CDT FRI MAY 27 2016

.Update...
Some minor tweaks made to this evening`s forecast. Light showers
moving into the western sections of the Texas Panhandle, but very
little if any moisture is expected to hit the ground.

Garcia

&&

.Prev Discussion... /Issued 618 PM CDT FRI MAY 27 2016/

Aviation...
Gusty winds should continue for another couple of hours at GUY and
DHT, winds at AMA should remain at or below 10 knots through this
forecast. A TSRA may affect DHT early in this forecast...so have
inserted a tempo group for this possibility. Skies should remain VFR
for all sites through this forecast. North and northwest winds will
flip around to the south by early afternoon on Saturday, but speeds
should remain around 10 knots or less.

Prev Discussion... /Issued 317 PM CDT FRI MAY 27 2016/

Short Term...Tonight...Shortwave trof moving rapidly through base
of mid- level trof will generate light precipitation in the very near
term, primarily along post-frontal convergence zone currently running
from near Beaver to Borger to Amarillo. However, expect that
shortwave trof`s influence will depart before 6 PM, with chances for
measurable precipitation remaining miniscule. Expect clouds to
decrease overnight with overnight low temperatures mainly in the 45
to 55 degree range.

Cockrell

Long Term...Saturday through Thursday night...A shortwave ridge will
rapidly pass over the combined Panhandles on Saturday ahead of an
incoming shortwave trough Saturday afternoon. Weak isentropic lift in
association with passing shortwave & vorticity maximum will present
a slight chance of thunderstorms moving east across the Oklahoma and
far northern Texas Panhandles. Instability with convection will be
limited, as MLCAPE is forecasted to be around 300-500 J/kg, but a
significant inverted-V signature suggests that there is potential for
gusty winds with any shower or thunderstorm activity. This shortwave
should clear the area by Saturday night ending chances of convection
during the evening hours.

For Sunday, a complicated weather patterns is expected to develop
over the combined Panhandles. This section of the discussion will
focus on the severe weather potential, with an adjoining hydrology
section provided below. An slow moving upper level low over southern
California will bring southwesterly flow into the region. A
negatively tilted shortwave trough will move over the combined
Panhandles on Saturday, with lee side cyclogenesis expected over far
southeastern Colorado. Model guidance has come into better agreement
of approximate location where the low pressure system will form. Vigorous
moisture return ahead of a sharpening dryline in eastern New Mexico
and a northward moving warm front will help bring high temperatures
in the mid 80s and dew point temperatures in the mid 50s to lower
60s. Though there is some lingering uncertainty on where exactly the
frontal boundary will stall, there is confidence in the development
of instability across the southern and eastern portions of the
combined Panhandles. In the warm sector and ahead of the dryline,
MLCAPE is expected to be around 1500-2500 J/kg with effective bulk
shear around 35-45 kts and increasing shear further south. With
diffluence aloft, and strong isentropic lift across the stalled
boundary, there is favorable dynamics for organized severe
convection. Storms may possibly form in a southwest to northeast
linear mode across the Panhandles, with discrete supercells possible
ahead of this line in the southeastern Texas Panhandle. Large hail
and damaging winds are likely, with a tornado or two possible with
any discrete supercell formation. As the line of storms moves
southeast, a cold pool may develop along and behind these storms
precluding the main threats towards gust fronts and heavy rainfall
late Sunday.

On Monday, the upper low will slowly progress towards Arizona and
continue to place our region under southwesterly flow aloft. Another
negatively shortwave trough will move across the combined Panhandles,
with a dryline sharpening up along the central portions of the
region. Instability will potentially be more favorable for the
eastern half of the area, but will need to see how worked over the
area is from Sunday`s activity before knowing how widespread severe
weather could be in our region. At present, have forecasted high
temperatures in the mid 80s with dew points in the mid-40s to the
west and the mid 60s to the east.

Tuesday through Thursday will remain active, as the upper low progged
to be over Arizona will open up into the longwave pattern as an upper
low moves southeast into Wyoming on Tuesday. Longwave trough will
progress east on Wednesday and Thursday with another leeside
cyclogenesis possible on Wednesday. Thunderstorms will be possible
on each day across the region, though it is too early to determine
whether severe weather is possible. Highs during the extended period
will be mid 70s to mid 80s, which is near to slightly below normal
for this time of year.

Bieda

Aviation...Previous Discussion...18Z TAFs...Cold air aloft associated
with closed low passing just north of forecast area may assist in
production of showers and thunderstorms this afternoon. Greatest
potential for convection will be across northern areas...where some
wrap-around low-level moisture is expected, and where sharply curved
flow will produce enhanced vorticity. Otherwise, vfr conditions
expected to prevail for this forecast.

Cockrell

Hydrology...A strong moisture return expected Sunday, along with a
potentially stationary boundary across the southwestern to
northeastern combined Panhandles, will bring the possibility for
heavy rain across the area. Organized thunderstorms, potentially
linear along a stalled frontal boundary, is forecasted with discrete
supercells possible in the southeastern portions of the area.
Precipitable water values is forecasted to be between 1.20-1.40
inches, which is in the 99th percentile for our region this time of
year. The potential for slow moving southeasterly propagation of
a line of thunderstorms will place the combined Panhandles under a
threat of localized flooding or flash flooding. Instances of creek
and river flooding, especially over the southeastern Texas Panhandle,
is possible due to previous rainfall. The flood threat will remain
through early next week as thunderstorms are possible through early
next week as active weather continues.

Bieda

&&

.AMA Watches/Warnings/Advisories...
TX...NONE.
OK...NONE.

&&

$$



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