Special Weather Statement, NWS Amarillo, TX

Area Forecast Discussion
National Weather Service Amarillo TX
153 PM CDT Mon Aug 16 2021

.SHORT TERM...This Afternoon through Tomorrow Night...

A somewhat active Monday with the potential for locally heavy
rainfall, localized damaging winds, and perhaps some severe hail
continues through this evening. Additionally, an isolated brief
tornado cannot be completely ruled out.

This morning and the early afternoon saw convection initially
develop in the northeastern Panhandles and adjacent areas of
mainland Oklahoma ahead of a weak impulse in the northerly flow
aloft, leading to a radar estimated 4 inches of rainfall southwest
of Miami. This convection generated a slow westward moving outflow
boundary. Convergence along this boundary has helped to kick off
additional thunderstorms over the past several hours. In addition to
thunderstorms, current observations depict an upper wave moving
south toward the Panhandles over the KS/CO border. At the surface,
temperatures are generally in the 80s west of the outflow boundary
with dewpoints in the 60s. Latest SPC mesoanalysis suggests 1500-
2000 J/kg of MLCAPE is present along with PWAT values around 1.25",
above the 75th percentile for this time of year.

This afternoon and evening, expect thunderstorms to continue to fill
in as low level moisture continues to advect northward and the wave
approaches from the north. Generation will focus on two areas: 1)
along and east of the outflow boundary, which is currently located
along a Guymon-Borger-Clarendon line, and 2) In the southwestern
quadrant of the Texas Panhandle, where a robust cumulus field has
developed and where short term guidance suggests 700mb thetaE is
maximized. Convection should reach its zenith around 3-5pm when the
thetaE axis and the outflow boundary meet, roughly in the central
and south central TX Panhandle. As for hazards, flow aloft continues
to be anemic, which favors both slow storm motions and a general
lack of storm organization - 0-6km bulk shear values are around 5 to
10 knots. In concert with those PWAT values mentioned above, locally
heavy rainfall appears to be the primary threat, especially in any
urbanized areas that manage to see a thunderstorm. The weak shear
suggests the hail threat will be transitory and limited to instances
when outflow boundaries collide leading to localized stronger
updrafts. Finally, with DCAPE around 1000 J/kg, localized damaging
wind are a potential threat as well. Additionally, areas east of the
outflow boundary that manage to regain surface based instability
will have a very small but present tornado risk, as 0-500m helicity
in this area is around 50 m2/s2 due to the localized easterly
surface winds. Expect convection to push south of the area this
evening as the upper wave progresses southward.

Tomorrow, the upper trough looks to linger over a SE NM to SW OK
axis. At the surface, cyclonic flow over the central and northern
Rockies will promote lee surface troughing in E CO, allowing
southerly moist advection to continue, particularly into the SE TX
Panhandle. Much will depend on the location of the upper trough, but
should this linger a bit to the northwest of where operational
guidance now depicts in, any perturbations rotating around this
feature would likely generate thunderstorms in the southeastern
Panhandles. A small step upward in deep layer shear suggests a more
prominent hail risk to go along with the continued risk for damaging
winds.

Ferguson

&&

.LONG TERM....LONG TERM...Wednesday Through Sunday Night...Upper level trough
over the Pacific Northwest with a high pressure system just off the
east coast of the Carolinas.  The return flow from the Gulf of
Mexico tends to favor moisture more along the Mississippi River
Valley and surrounding areas.  Overall the models are trending
drier, with exception of the southeast Panhandles.  The NBM has
pretty much gone dry, which may be a bit of an overstep for that
southeast.  There is also the upper trough that will come into the
central CONUS on Thursday.  There is plenty of moisture with this
system, however it does suggest that southern CO/KS will be the
extent of where the moisture expands, as drier southwest flow will
be dry slotting the area.

Saturday, a weak high will start to strengthen over the southern
Gulf and that will allow moisture from the Gulf to be closer to the
southeast Panhandles.  By Sunday the high will strengthen and
amplify into a much broader dominate high, centered over the
Arkansas/Louisiana area.  This will certainly favor a drier
Panhandles scenario for the end of the forecast period.

Overall, the forecast looks to be mostly dry for the time being, but
there is certainly room for pops to come up if there is even the
slightest deviation with the approaching Pac NW trough, or the Gulf
moisture transport.

Weber

&&

.AVIATION...18Z TAFs...
Primary aviation concern is the prospect of thunder at all TAF
sites over the next 6 hours. A few storms are attempting to
develop near GUY currently, but the favored area for storm
generation will slowly shift to the west and south over the next
few hours. Have thus gone with a VCTS mention at this location. At
AMA, latest guidance and observations suggests a window later this
afternoon where thunderstorms may slide south over the terminal,
so have refined the ongoing TEMPO group. Farther west at DHT,
ongoing cloudiness suggests that this area may miss out on
thunderstorms, so have carried fair weather through the TAF.
Otherwise, expect generally some form of southerly winds over the
next 24 hours, with erratic changes should any thunderstorms
occur.

Ferguson

&&

.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX                87  63  87  65  88 /  30  20   5   5   5
Beaver OK                  88  63  92  66  93 /  30  20  10   0   5
Boise City OK              88  59  90  62  90 /  20  10   5   0   0
Borger TX                  90  66  93  68  93 /  40  10   0   0   5
Boys Ranch TX              89  63  90  65  90 /  20  10   0   0   5
Canyon TX                  87  63  87  64  87 /  30  30  10   5   5
Clarendon TX               89  66  88  67  87 /  30  30  20   5  10
Dalhart TX                 87  59  88  60  89 /  30  10   5   0   5
Guymon OK                  89  62  92  65  93 /  30  10   5   0   0
Hereford TX                87  62  87  63  89 /  30  30  10   5   5
Lipscomb TX                87  65  90  66  90 /  40  20  10   5   5
Pampa TX                   88  64  88  65  88 /  40  20   5   0   5
Shamrock TX                89  66  90  66  88 /  30  30  20   5  10
Wellington TX              91  68  91  67  90 /  30  30  20  10  10

&&

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

&&

77/89/77

Hazardous Weather Outlook
National Weather Service Amarillo TX
154 PM CDT Mon Aug 16 2021

OKZ001>003-TXZ001>020-317-170700-
Cimarron-Texas-Beaver-Dallam-Sherman-Hansford-Ochiltree-Lipscomb-
Hartley-Moore-Hutchinson-Roberts-Hemphill-Oldham-Potter-Carson-
Gray-Wheeler-Deaf Smith-Randall-Armstrong-Donley-Collingsworth-
Palo Duro Canyon-
154 PM CDT Mon Aug 16 2021

This Hazardous Weather Outlook is for the Texas and Oklahoma
Panhandles.

.DAY ONE...Tonight.

Thunderstorms will be possible across the entire Texas and
Oklahoma Panhandles for the rest of the evening. Storms may be
strong to severe across the Panhandles with hail and damaging wind
gusts as the main threat. Localized flooding is possible due to
slow moving storms and heavy rainfall.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Thunderstorms will continue to be possible in the southeast on
Thursday and Friday.

.SPOTTER INFORMATION STATEMENT...

Limited spotter activation may become necessary today and tonight.

Special Weather Statement
National Weather Service Amarillo TX
1257 PM CDT Mon Aug 16 2021

TXZ008-161830-
Hutchinson TX-
1257 PM CDT Mon Aug 16 2021

...A strong thunderstorm will impact portions of southeastern
Hutchinson County through 130 PM CDT...

At 1256 PM CDT, Doppler radar was tracking a strong thunderstorm 7
miles northeast of Borger, moving east at 10 mph.

HAZARD...Wind gusts of 50 to 55 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Borger.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3567 10138 3578 10141 3595 10109 3566 10109
TIME...MOT...LOC 1756Z 255DEG 9KT 3576 10133

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...55 MPH

MJG

Special Weather Statement
National Weather Service Amarillo TX
128 PM CDT Mon Aug 16 2021

TXZ006-011-161900-
Hartley TX-Oldham TX-
128 PM CDT Mon Aug 16 2021

...A strong thunderstorm will impact portions of eastern Oldham and
southeastern Hartley Counties through 200 PM CDT...

At 127 PM CDT, Doppler radar was tracking a strong thunderstorm 5
miles west of Boys Ranch, or 18 miles north of Vega, moving northeast
at 15 mph.

HAZARD...Wind gusts up to 50 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Channing and Boys Ranch.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3527 10229 3530 10262 3575 10240 3574 10217
      3553 10217
TIME...MOT...LOC 1827Z 203DEG 14KT 3551 10236

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 MPH

MJG

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PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE AMARILLO TX
204 PM CDT MON AUG 16 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0108 PM     TSTM WND GST     9 NNW PAMPA             35.66N 101.04W
08/16/2021  E60 MPH          ROBERTS            TX   TRAINED SPOTTER

            CORRECTS REPORT SOURCE FROM PREVIOUS TSTM
            WND GST REPORT FROM 9 NNW PAMPA. SPOTTER
            ESTIMATES A 60 MPH GUST WITH TREES BENDING
            NEARLY 90 DEGREES.

&&

APF

Special Weather Statement
National Weather Service Amarillo TX
224 PM CDT Mon Aug 16 2021

TXZ007-162000-
Moore TX-
224 PM CDT Mon Aug 16 2021

...A strong thunderstorm will impact portions of east central Moore
County through 300 PM CDT...

At 223 PM CDT, Doppler radar was tracking a strong thunderstorm 7
miles east of Dumas, moving east at 5 mph. Additional strong storms
may also build west towards Dumas.

HAZARD...Wind gusts of 50 to 55 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Dumas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3579 10199 3591 10198 3592 10164 3570 10164
TIME...MOT...LOC 1923Z 267DEG 6KT 3583 10183

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...55 MPH

MJG