Tornado Watch 503

Issued

Oct 21, 2017, 3:06 PM CDT (20:06 UTC)

Expired

Oct 21, 2017, 10:00 PM CDT

In force

7 hr

Issued by

the Storm Prediction Center

Largest hail expected

2.5 in

Strongest gust expected

60 kt

The Norman radar (KTLX), 83 km from the middle of the area, began a volume at 20:06 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

40%

One or more EF2 to EF5 tornadoes

20%

Ten or more severe wind reports

60%

One or more gusts of 65 knots or more

20%

Ten or more severe hail reports

60%

One or more hailstones of 2 inches or more

50%

Six or more combined severe hail and wind reports

95%

• Mesoscale Discussion 1722Oct 21, 2:36 PM CDT
• Mesoscale Discussion 1724Oct 21, 5:05 PM CDT
• Mesoscale Discussion 1726Oct 21, 5:41 PM CDT
• Mesoscale Discussion 1727Oct 21, 6:40 PM CDT
• Mesoscale Discussion 1729Oct 21, 8:34 PM CDT

354 
WWUS20 KWNS 212002
SEL3  
SPC WW 212002
OKZ000-TXZ000-220300-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 503
NWS Storm Prediction Center Norman OK
300 PM CDT Sat Oct 21 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Western and central Oklahoma
  Northwest Texas

* Effective this Saturday afternoon and evening from 300 PM until
  1000 PM CDT.

* Primary threats include...
  A couple tornadoes possible
  Scattered large hail likely with isolated very large hail events
    to 2.5 inches in diameter possible
  Scattered damaging wind gusts to 70 mph likely

SUMMARY...Thunderstorm development is expected around 4pm, with an
increase in storm coverage/intensity into this evening.  More
isolated supercells with very large hail will be possible initially
across western Oklahoma and northwest Texas.  Storms will then grow
upscale into a more solid squall line by late evening, when damaging
winds will become the more common threat.  A tornado or two could
occur with the initial discrete supercells, as well as later this
evening with circulations embedded in the developing line across
central Oklahoma.

The tornado watch area is approximately along and 60 statute miles
east and west of a line from 45 miles west northwest of Ponca City
OK to 55 miles southwest of Wichita Falls TX. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU3).

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.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 502...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 2.5 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 24030.

...Thompson

Tornado Watches in Oklahoma, 2017Tornado Watches in Texas, 2017Every tornado watch in 2017

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.