Tornado Watch 1

Issued

Jan 21, 2018, 3:05 PM CST (21:05 UTC)

Expired

Jan 21, 2018, 11:00 PM CST

In force

8 hr

Issued by

the Storm Prediction Center

Largest hail expected

0.5 in

Strongest gust expected

60 kt

The Western Arkansas radar (KSRX), 85 km from the middle of the area, began a volume at 21:09 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

Two or more tornadoes

50%

One or more EF2 to EF5 tornadoes

20%

Ten or more severe wind reports

40%

One or more gusts of 65 knots or more

10%

Ten or more severe hail reports

10%

One or more hailstones of 2 inches or more

5%

Six or more combined severe hail and wind reports

70%

• Mesoscale Discussion 32Jan 21, 1:13 PM CST
• Mesoscale Discussion 34Jan 21, 6:25 PM CST
• Mesoscale Discussion 36Jan 21, 9:35 PM CST

616 
WWUS20 KWNS 212103
SEL1  
SPC WW 212103
ARZ000-OKZ000-TXZ000-220500-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 1
NWS Storm Prediction Center Norman OK
305 PM CST Sun Jan 21 2018

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Western Arkansas
  Eastern Oklahoma
  Northeastern Texas

* Effective this Sunday afternoon and evening from 305 PM until
  1100 PM CST.

* Primary threats include...
  A few tornadoes possible
  Scattered damaging wind gusts to 70 mph possible

SUMMARY...Thunderstorms will continue to slowly increase in coverage
and intensity this afternoon into this evening from north and
northeastern Texas into southeastern Oklahoma and western Arkansas
in advance of a strong storm system progressing eastward over the
Great Plains.  The storm environment will support some threat for
semi-discrete supercells for the next few hours, and then convection
should gradually grow upscale into more of a squall line tonight.  A
few tornadoes with the supercells and/or embedded circulations, as
well as damaging winds with bowing segments, will be possible.

The tornado watch area is approximately along and 65 statute miles
east and west of a line from 30 miles west northwest of Harrison AR
to 50 miles south southwest of Tyler TX. For a complete depiction of
the watch see the associated watch outline update (WOUS64 KWNS
WOU1).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.

&&

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 0.5 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 400. Mean
storm motion vector 22040.

...Thompson

Tornado Watches in Texas, 2018Tornado Watches in Arkansas, 2018Tornado Watches in Oklahoma, 2018Every tornado watch in 2018

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.