Area Forecast Discussion
Issued by NWS Amarillo, TX

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FXUS64 KAMA 161704
AFDAMA

Area Forecast Discussion
National Weather Service Amarillo TX
1204 PM CDT Wed Aug 16 2017

.AVIATION...

For the 18Z TAFs:

VFR conditions are expected at the terminals throughout the valid
TAF period. We should remain under clear to most clear skies
through this period with relatively light wind speeds.

Guerrero

&&

.PREV DISCUSSION... /Issued 631 AM CDT Wed Aug 16 2017/

AVIATION...12Z TAFS...

VFR conditions are expected over the next 24 hours. South to
southwest winds 5 to 15 knots still at KAMA but will become west
and northwest at KAMA by 14Z, and then all three TAF sites become
northerly by 18Z. Have noted some low cloud potential at KAMA and
KGUY as some guidance suggests enough clearing to maybe get a
thicker layer and KGUY just recently has bounced between BKN/SCT
around 2kft. Will keep FEW at KAMA through 14Z, but going with BKN
2kft at KGUY through 16Z. Storms don`t look favorable today and
therefore have kept them out of the TAFS.

Weber

PREV DISCUSSION... /Issued 343 AM CDT Wed Aug 16 2017/

DISCUSSION...
A slight change in the upper flow will bring a bit of change to
the Panhandles in the short run before we return to off and on
storms going into the weekend. Once the residual overnight storms
across the far eastern and northern zones, we could be looking at
a roughly 18 to 24 hour window of dry weather. This is the result
of a southward moving boundary and upper height rises over the
area. There are storms expected to develop across the boundary
this afternoon and evening, but the boundary is expected to be
just south of our area. There is a possibility that outflows will
push the boundary back to the north slightly and allow a storm to
move over the southeastern Texas Panhandle. Have retained low end
POPs to cover this possibility.

Thursday is expected to remain precip free until the late
afternoon hours as models depict storms developing along a
moisture boundary over the western zones. Storms that develop
during the afternoon hours will be more diurnally driven as a
shortwave is not expected until the late evening hours. Once this
shortwave arrives, it will help to sustain convection through the
better part of the overnight hours. Should storms form during the
afternoon hours as a result of heating, they would be forming in a
fairly conducive environment. Forecast CAPE values across the west
are shown to be in the 2000-4000 J/kg with deep layer shear of 25
to 30kt. With this scenario, a few strong to marginally severe
storms would be possible. Hail and damaging wind would be the
primary hazards. Instability lessens overnight to around the 2000
J/kg mark while shear increases to 30kt. Forecast PWATs are also
shown to be on the rise overnight so there will be a greater risk
from heavy rain and possible flooding later in the night compared
to the daytime storms. Storms should be coming to and by Friday
morning but a few models hold onto precip until 16Z.

Northwest flow aloft is expected over the Panhandle Friday and
Saturday as ridging build over the High Plains. This will keep the
area open to embedded shortwaves traversing the Southern High
Plains and bringing additional round of storms. While instability
is forecast to remain fairly consistent during the daylight hours,
our deep layer shear will be slightly lower (~20kt). This will
keep storm intensity limited but a rogue strong to marginally
sever storm can`t be ruled out. Our upper flow is expected to
shift again on Sunday to more of a southwesterly flow as the sub-
tropical high shifts east of the Panhandles. This will allow more
monsoonal moisture to surge back into the area and return the
risk of flooding/flash flooding.

&&

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

&&

$$

99/99



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