Severe Thunderstorm Warning 175, NWS Amarillo, TX

Area Forecast Discussion...UPDATED
National Weather Service Amarillo TX
639 PM CDT Thu Aug 6 2020

.AVIATION...
The best chance of thunderstorms looks to be at the GUY TAF site
this evening, so have added a tempo group there for some MVFR
conditions with a thunderstorm. Otherwise, skies are expected to
be VFR at all sites. Winds will be generally out of the south and
southwest at 15 to 20 knots with higher gusts especially Friday
morning at the AMA TAF site.

&&

.PREV DISCUSSION... /Issued 335 PM CDT Thu Aug 6 2020/

SHORT TERM...This Afternoon through Friday Afternoon...
A mesoscale convective vortex (MCV) noted on satellite will be
crossing the southern Texas Panhandle this afternoon. In addition,
a shortwave trof aloft is noted on water vapor in New Mexico and
Colorado, which will move into the combined Panhandles this
afternoon and evening. Both of these features together will help
bring showers and thunderstorms to the area, though cloud cover
that has persisted through time of writing will help lessen
coverage and reduce potential strength (mainly across the southern
Texas Panhandle). Forecast Skew-T soundings for later today shows
that 1000 to 1500 J/kg of MLCAPE in the northern Panhandles, with
500 to 1000 J/kg of MLCAPE in the southern Panhandles. These same
sounds further show high DCAPE values (around 1000 to 2000 J/kg)
across the region, suggesting strong support for downdraft winds
that could be strong to severe in nature (favoring northern
Panhandles). Bulk shear that these storms could act on remain in
the 20 to 30 kt range, giving some support for storms to survive
their initial updraft stage and potentially becoming multi cell
clusters with movement towards the east to southeast around 25 to
35 MPH. Thunderstorm activity should continue to initiate, having
the most coverage around 3 PM to 9 PM this afternoon/evening,
before waning into the overnight hours. High temperatures today
are expected to be in the mid to upper 90s (if not 100 in spots)
as clearing skies with ridge axis overhead promotes strong
insulation region wide.

On Friday, the weather pattern becomes less favorable as upper
level ridge moves closer to the region (centered just southeast or
around Lubbock). Upper level steering winds also lessen as a
result, with H5 temperatures across the region around -5 deg C.
High temperatures tomorrow owing to height increases aloft will
easily reach 100 in the central and eastern Texas and Oklahoma
Panhandles, with heat advisory criteria possible in Palo Duro
Canyon with a forecast high of 105 degrees. Have reduced ongoing
PoP chances as available instability will be less, and there is
not any sign of a perturbation in the flow supportive for
increasing chances of convective development. Despite this
reduction have held with slight chance of thunderstorms in the
extreme southwest in case storms in New Mexico move northeast
towards the region.

Bieda

LONG TERM...Friday Evening Through Wednesday Night...
Southwest flow will continue through the weekend with monsoon
moisture continued over the Panhandles. Strong daytime heating
will likely trigger some isolated to scattered storms across the
western and possibly central Panhandles. Friday evening there may
be just enough forcing an moisture that ML CAPE values could be
around 1000 J/kg, mainly in the SW Panhandle. Shear isn't great,
around 20-30kts, but given the inverted V profile strong to severe
storms can't be ruled out. Chatted with SPC and given the small
area of concern, it may be more on a Day 1 outlook to see
something show up.

Upper level trof expected to move east across southern Canada.
This will suppress the high to more of a zonal flow, and there may
be just enough of a weak cold front to add lift and get storms
going early next week. Thus, thunderstorm threats continue through
Tuesday. As the system exits to the east the high will rebuild
over the four corners region and we will be back in northwest
flow. Right now pops are on the low side, but we still could see
storms develop off the NM mountains and track southeast into the
Panhandles. So pops are not completely shut down.

Weber

AVIATION...18Z TAFs...VFR conditions will prevail at all
terminals, though showers and thunderstorms are possible this
afternoon and evening. The highest confidence was placed with
KAMA, as the better parameters align BTWN 06/21Z thru 07/00Z. Any
further updates to these chances for the other terminals will be
handled with amendments. Otherwise, southwest winds will become
southerly and be breezy through the evening and overnight hours
BTWN 10 to 20 kts. Wind shear may become a problem at KGUY as a
low-level jet off the surface around 40 kts could exist overnight.

Bieda

&&

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

&&

15/29