Special Weather Statement, NWS Amarillo, TX

Area Forecast Discussion
National Weather Service Amarillo TX
115 PM CDT Sun May 30 2021

.AVIATION...
CIGS have finally been raising and are generally MVFR or above
for most, but few small areas of IFR remain including at GUY.
These should also lift through mid aftn. Widespread showers and
thunderstorms are expected tonight and these will have potential
to be severe and produce very heavy rainfall. The bulk of the
activity will occur between 00Z and 08Z with a main complex that
will move west to east and this is timing provided in TAFs.
Isolated storms are possible prior to the main line and additional
scattered weaker storms are expected after the main activity
through 18z, but these are not accounted for in TAFs currently
directly given uncertainty. IFR CIGS are expected to again develop
in the wake of these storms as a weak boundary slides into the
area and abundant low level moisture remains in place.

Gittinger

&&

.PREV DISCUSSION... /Issued 645 AM CDT Sun May 30 2021/

AVIATION...
For the 12Z TAFs, a low confidence and complicated forecast is
the theme of this cycle. Expect periods of showers and
thunderstorms across the area as an upper level storm system
organizes over the southwest states. Confidence is low on timing
individual rounds of precipitation as well as low cigs, and
amendments may become necessary.

02

PREV DISCUSSION... /Issued 433 AM CDT Sun May 30 2021/

DISCUSSION...
Rather busy night last evening into this shift with severe
weather. The active weather pattern will continue. For today
through Memorial Day, an upper level trof of low pressure is
forecast to develop over the southwest states. Models are in
decent agreement on this scenario. Plenty of moisture is expected
to be in place across the area. Minor impulses are progged to
eject northeast from the main storm system, and will assist in the
development of more showers and thunderstorms during this time
period. Some storms may become severe late this afternoon and
evening, with large hail and damaging winds the primary hazards
due to the combination of an approaching minor upper level
shortwave trof, an unstable atmosphere, adequate CAPE and shear,
and more than sufficient moisture. Also, there will be a window
late this afternoon into the mid evening for the potential of an
isolated tornado across the western half of the area. In addition,
the threat for heavy rainfall from the strongest storms will
continue, which could lead to flooding or flash flooding today
into Memorial Day.

Latest medium range model guidance continues to suggest a
downward trend in precipitation chances for Tuesday and Wednesday
as part of the upper level trof advances eastward and away from
the area, while the remaining part drifts southwest to a position
near Baja, California and becomes quasi-stationary. A general
weakness in the upper level pattern or some semblance of weak
upper level troffing is progged by medium range models Thursday
into Saturday, which warrants the possibility of at least isold
tstm development across parts of the fcst area durg this time
period. Medium range models are hinting at this and is now reflected
in NBM pops for late this week. This fcst pckg follows suit by
utilizing NBM pops and temperatures.

02

HYDROLOGY...Today through Memorial Day.
Multiple ingredients will be in place through Memorial Day to
warrant a concern for heavy rainfall across the forecast area
which could lead to flooding or flash flooding. Plenty of deep
moisture will be present as seen by progged PWAT values which are
slated to exceed the 90th percentile and well above climatological
values for late May. Minor impulses ejecting northeast from the
main upper low over the southwest states will assist in providing
the necessary lift for shower and tstm development durg this time
period. Also, the potential exists for repeat development of
showers and tstms and attendant training of the precipitation,
which would increase the threat for flooding or flash flooding.
Finally, recent rainfall during the past couple weeks has
resulted in wet soils and grounds across much of the fcst area.
While the above elements are favorable for flooding and flash
flooding, there still exists one big caveat that could throw a
wrench into this scenario. Specifically, how this morning's
precipitation evolution affects the atmosphere's recovery period
later today will strongly dictate how well the next round of
showers and storms impacts the area later this afternoon and
tonight. If our region remains too cool, cloudy, and more stable
than is currently anticipated, then the extent and magnitude of
additional precipitation development will be problematic. Therefore,
have held off issuance of any flood highlights for this pckg due
to this uncertainty just outlined. Nevertheless, Flood/Flash Flood
Watches may still need to be considered by later shifts for later
today or tonight if confidence increases as to where such headlines
may be needed based on expected rainfall accumulations.

02

&&

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

&&

Hazardous Weather Outlook
National Weather Service Amarillo TX
250 PM CDT Sun May 30 2021

OKZ001>003-TXZ001>020-317-311200-
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-
250 PM CDT Sun May 30 2021

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

.DAY ONE...Through Tonight.

Thunderstorms are expected to develop or move in from the west
through tonight across the Texas and Oklahoma Panhandles. Some
storms may become severe late this afternoon and evening, with
large hail and damaging winds the primary hazards. However, an
isolated tornado cannot be ruled out across the far western
sections of the area. In addition, the strongest storms will be
capable of producing heavy rainfall, which may lead to flooding or
flash flooding. A Flood Watch is in effect for all of the
Panhandles this evening through Monday morning.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

Thunderstorms will be possible across the Texas and Oklahoma
Panhandles Memorial Day through Wednesday night, and then across
parts of the area Thursday through Saturday. Any storms that
develop are expected to remain below severe levels at this time.
In addition, the strongest storms on Memorial Day will be capable
of producing heavy rainfall, which may lead to flooding or flash
flooding.

.SPOTTER INFORMATION STATEMENT...

Spotter groups and Emergency Management officials across the Texas
and Oklahoma Panhandles should remain alert and be ready for
possible activation through tonight.

Schneider

Special Weather Statement
National Weather Service Amarillo TX
103 PM CDT Sun May 30 2021

OKZ003-301845-
Beaver OK-
103 PM CDT Sun May 30 2021

...SIGNIFICANT WEATHER ADVISORY FOR EASTERN BEAVER COUNTY UNTIL 145
PM CDT...

At 102 PM CDT, Doppler radar was tracking a strong thunderstorm near
Slapout, or 16 miles west of Laverne, moving northeast at 35 mph.

Penny size hail will be possible with this storm.

Locations impacted include...
Gate, Knowles, Elmwood and Slapout.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take shelter in a sturdy building if threatening weather approaches.

&&

LAT...LON 3695 10000 3653 10001 3651 10005 3659 10062
      3700 10026 3700 10013
TIME...MOT...LOC 1802Z 237DEG 31KT 3663 10017

MJG

Special Weather Statement
National Weather Service Amarillo TX
335 PM CDT Sun May 30 2021

OKZ001-302100-
Cimarron OK-
335 PM CDT Sun May 30 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN CIMARRON COUNTY
UNTIL 400 PM CDT...

At 335 PM CDT, Doppler radar was tracking a strong thunderstorm 10
miles northeast of Black Mesa Park, or 18 miles northwest of Boise
City, moving northeast at 25 mph.

Penny size hail and wind gusts of 50 to 55 mph will be possible with
this storm.

This storm will remain over mainly rural areas of northwestern
Cimarron County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take shelter in a sturdy building if threatening weather approaches.

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

&&

LAT...LON 3699 10271 3699 10245 3683 10281 3690 10289
      3700 10281
TIME...MOT...LOC 2035Z 222DEG 23KT 3693 10273

DGW