Area Forecast Discussion
Issued by NWS Amarillo, TX

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166
FXUS64 KAMA 230003
AFDAMA

Area Forecast Discussion
National Weather Service Amarillo TX
703 PM CDT Tue Aug 22 2017

.AVIATION/UPDATE...
TAFs are tricky this go around as cigs bounce around between VFR,
MVFR, IFR, and potentially LIFR later tonight. For the most part
expect MVFR or VFR cigs through midnight with a quick storm or 2
likely at KAMA early this evening. Cigs should begin to lower
after midnight, with LIFR cigs possible at KAMA and KDHT. Vsbys
could also be reduced with some mist and/or fog and maybe even a
bit of drizzle. Flight conditions will slowly rebound Wednesday
with all 3 sites having a good chc to see VFR conditions return
by the afternoon.

Sent a quick update to the forecast to tweak precip chcs this
evening and overnight. Appears rain will not be as widespread as
we initially thought with isolated to scattered showers and
storms more the norm.

Simpson
&&

.PREV DISCUSSION... /Issued 335 PM CDT Tue Aug 22 2017/

DISCUSSION...
We`ve already got storms develop across the southern Texas
Panhandles along a southward moving cold front. We continue to see
high climatological PWAT values across the Panhandles and storms
motions are expected to be very slow. For this reason, storms will
have the potential to produce heavy rain which could easily result
in flooding or flash flooding. Meso-analysis shows instability
reaching around 3500 J/kg with very little shear. As a result
pulse storms which could produce damaging winds and possibly hail
are likely. Storms are expected to persist through the evening
hours before dandling tomorrow morning. The risk for severe
weather will be greater this afternoon while the heavy rain threat
will persist through the overnight hours.

Residual storms are expected across the southern and western Texas
Panhandle Wednesday morning. There looks to be a lull around the
15Z to 21Z timeframe Wednesday as the vort lobe which sustained
storms overnight moves south of the area. With that being said,
the lull will be short lived as another shortwave within
northwest flow moves along the eastern New Mexico Plains Wednesday
afternoon. This will allow storms to develop and move south-
southeast along the higher terrain in SE Colorado and NE New
Mexico Wednesday evening. An isolated storm could move across the
stateline to enter the far western Texas and Oklahoma Panhandles.
As we move into the daytime hours on Thursday, the shortwave will
move over our area which will allow storms to move across the
better portion of the western and southern Texas Panhandle.
Instability at this time will be around the 1500 - 2000 J/kg
range while deep layer shear is around the 20kt mark. While a
storm could pulse up into the severe category, widespread severe
weather is not anticipated. PWATs will still be up so the chance
for localized flooding is a possibility.

Friday through the start of next week holds a great deal of
uncertainty as the impacts of the remnants of Harvey are up in the
air. The ECMWF and CMC keep Harvey much further south than the
aggressive GFS. The further north position shown in the GFS has
been discounted as of now. The forecast is based on a heavy
leaning ECMWF/CMC blend. The result is low end PoPs through the
weekend and into the start of next week.

&&

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

&&

$$

9/36



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