Alert archive / Oklahoma / Tornado Watches in 2015

Tornado Watch 177

May 16, 201543 counties in Oklahoma

The Storm Prediction Center issued this tornado watch at May 16, 2015, 4:00 PM CDT for 43 counties in Oklahoma. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued: May 16, 2015, 4:00 PM CDT (21:00 UTC)
Expired: May 17, 2015, 12:00 AM CDT
In force: 8 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2 in
Strongest gust expected: 60 kt

All 43 counties

Alfalfa County, OK, Atoka County, OK, Blaine County, OK, Bryan County, OK, Caddo County, OK, Canadian County, OK, Carter County, OK, Cleveland County, OK, Coal County, OK, Comanche County, OK, Cotton County, OK, Custer County, OK, Dewey County, OK, Ellis County, OK, Garfield County, OK, Garvin County, OK, Grady County, OK, Grant County, OK, Harper County, OK, Hughes County, OK, Jefferson County, OK, Johnston County, OK, Kay County, OK, Kingfisher County, OK, Kiowa County, OK, Lincoln County, OK, Logan County, OK, Love County, OK, Major County, OK, Marshall County, OK, McClain County, OK, Murray County, OK, Noble County, OK, Oklahoma County, OK, Payne County, OK, Pontotoc County, OK, Pottawatomie County, OK, Seminole County, OK, Stephens County, OK, Tillman County, OK, Washita County, OK, Woods County, OK, Woodward County, OK

The radar

The Norman radar (KTLX), 101 km from the middle of the area, began a volume at 21:10 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 60%
One or more EF2 to EF5 tornadoes: 30%
Ten or more severe wind reports: 40%
One or more gusts of 65 knots or more: 10%
Ten or more severe hail reports: 30%
One or more hailstones of 2 inches or more: 30%
Six or more combined severe hail and wind reports: 60%

Warnings issued inside it

46 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
May 16, 4:15 PM CDT	Severe Thunderstorm Warning	OUN	Beckham, Custer, Dewey, Ellis, Roger Mills	45 min
May 16, 4:58 PM CDT	Severe Thunderstorm Warning	OUN	Beckham, Custer, Dewey, Ellis, Roger Mills, Washita	47 min
May 16, 5:11 PM CDT	Severe Thunderstorm Warning	OUN	Harmon, Jackson, Kiowa, Tillman	49 min
May 16, 5:20 PM CDT	Severe Thunderstorm Warning	OUN	Harper, Major, Woods, Woodward	40 min
May 16, 5:25 PM CDT	Tornado Warning	OUN	Jackson, Tillman	35 min
May 16, 5:30 PM CDT	Severe Thunderstorm Warning	OUN	Beckham, Greer, Jackson, Kiowa, Washita	45 min
May 16, 5:41 PM CDT	Tornado Warning	OUN	Beckham, Custer, Washita	34 min
May 16, 5:46 PM CDT	Severe Thunderstorm Warning	OUN	Alfalfa, Dewey, Major, Woods	44 min
May 16, 5:54 PM CDT	Severe Thunderstorm Warning	OUN	Beckham, Custer, Roger Mills	36 min
May 16, 5:59 PM CDT	Tornado Warning Considerable damage threat	OUN	Jackson, Kiowa, Tillman	31 min
May 16, 6:12 PM CDT	Tornado Warning	OUN	Major	33 min
May 16, 6:13 PM CDT	Severe Thunderstorm Warning	OUN	Tillman	47 min
May 16, 6:18 PM CDT	Severe Thunderstorm Warning	OUN	Comanche, Jackson, Kiowa, Tillman	42 min
May 16, 6:27 PM CDT	Tornado Warning	OUN	Comanche, Kiowa, Tillman	33 min
May 16, 6:35 PM CDT	Flash Flood Warning	OUN	Caddo, Comanche, Jackson, Kiowa, Tillman	2 hr
May 16, 6:38 PM CDT	Tornado Warning	OUN	Alfalfa, Major	37 min
May 16, 6:50 PM CDT	Tornado Warning	OUN	Tillman	25 min
May 16, 6:57 PM CDT	Severe Thunderstorm Warning	OUN	Caddo, Comanche, Kiowa, Tillman	48 min
May 16, 7:11 PM CDT	Severe Thunderstorm Warning	OUN	Alfalfa, Grant	49 min
May 16, 7:12 PM CDT	Tornado Warning	OUN	Caddo, Comanche	33 min
May 16, 7:15 PM CDT	Tornado Warning	OUN	Cotton, Tillman	30 min
May 16, 7:41 PM CDT	Tornado Warning	OUN	Comanche, Cotton	34 min
May 16, 7:42 PM CDT	Tornado Warning	OUN	Caddo, Comanche	33 min
May 16, 8:06 PM CDT	Tornado Warning Tornado observed	OUN	Caddo, Grady	24 min
May 16, 8:11 PM CDT	Tornado Warning	OUN	Comanche, Grady, Stephens	34 min
May 16, 8:12 PM CDT	Tornado Warning	OUN	Cotton	33 min
May 16, 8:18 PM CDT	Severe Thunderstorm Warning	OUN	Cotton, Tillman	42 min
May 16, 8:31 PM CDT	Severe Thunderstorm Warning	OUN	Canadian, Cleveland, Garvin, Grady, McClain, Oklahoma	44 min
May 16, 8:36 PM CDT	Tornado Warning	OUN	Pottawatomie	24 min
May 16, 8:38 PM CDT	Severe Thunderstorm Warning	OUN	Garfield, Grant, Kay, Kingfisher, Logan, Noble and 1 more	52 min
May 16, 8:43 PM CDT	Severe Thunderstorm Warning	OUN	Carter, Comanche, Cotton, Garvin, Grady, McClain and 1 more	32 min
May 16, 8:45 PM CDT	Tornado Warning	OUN	Cotton, Jefferson, Stephens	30 min
May 16, 8:53 PM CDT	Flash Flood Warning	OUN	Comanche, Cotton, Jefferson, Stephens, Tillman	3 hr
May 16, 8:57 PM CDT	Tornado Warning	OUN	Lincoln, Pottawatomie, Seminole	33 min
May 16, 9:04 PM CDT	Tornado Warning	OUN	Pottawatomie, Seminole	26 min
May 16, 9:11 PM CDT	Severe Thunderstorm Warning	OUN	Carter, Cotton, Garvin, Grady, Jefferson, Murray and 1 more	49 min
May 16, 9:14 PM CDT	Severe Thunderstorm Warning	OUN	Cleveland, Lincoln, McClain, Oklahoma, Pottawatomie	46 min
May 16, 9:26 PM CDT	Severe Thunderstorm Warning	OUN	Lincoln, Logan, Noble, Payne	49 min
May 16, 9:26 PM CDT	Tornado Warning	OUN	Lincoln	20 min
May 16, 9:28 PM CDT	Severe Thunderstorm Warning	OUN	Kay	35 min
May 16, 9:30 PM CDT	Tornado Warning	OUN	Seminole	30 min
May 16, 9:59 PM CDT	Severe Thunderstorm Warning	OUN	Carter, Garvin, Jefferson, Love, Murray, Pontotoc and 1 more	46 min
May 16, 10:01 PM CDT	Severe Thunderstorm Warning	OUN	Cleveland, Hughes, Lincoln, McClain, Oklahoma, Pottawatomie and 1 more	44 min
May 16, 10:43 PM CDT	Severe Thunderstorm Warning	OUN	Carter, Garvin, Jefferson, Johnston, Love, Murray and 1 more	47 min
May 16, 11:15 PM CDT	Severe Thunderstorm Warning	OUN	Hughes	45 min
May 16, 11:33 PM CDT	Severe Thunderstorm Warning	OUN	Atoka, Bryan, Carter, Coal, Johnston, Love and 3 more	42 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Norman, OK (KOUN), launched 12:00Z, 9.0 hours before the alert went out and 99 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 538 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 590 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 137 m²/s²
0-3 km storm-relative helicity: 107 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 4.6

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

424 
WWUS20 KWNS 162057
SEL7  
SPC WW 162057
OKZ000-TXZ000-170500-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 177
NWS STORM PREDICTION CENTER NORMAN OK
400 PM CDT SAT MAY 16 2015

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF 
  CENTRAL OKLAHOMA
  NORTHWEST TEXAS

* EFFECTIVE THIS SATURDAY AFTERNOON FROM 400 PM UNTIL MIDNIGHT
  CDT.

* PRIMARY THREATS INCLUDE...
  A FEW TORNADOES LIKELY WITH A COUPLE INTENSE TORNADOES POSSIBLE
  SCATTERED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE
  ISOLATED VERY LARGE HAIL EVENTS TO 2 INCHES IN DIAMETER POSSIBLE

SUMMARY...SEVERE STORMS INCLUDING SUPERCELLS AND LINE SEGMENTS WILL
DEVELOP EWD INTO CNTRL OK THIS EVENING. LARGE HAIL...DAMAGING WIND
AND A FEW TORNADOES WILL BE POSSIBLE. POTENTIAL ALSO EXISTS FOR A
COUPLE OF STRONG TORNADOES.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 70 STATUTE
MILES EAST AND WEST OF A LINE FROM 15 MILES NORTH OF ALVA
OKLAHOMA TO 25 MILES SOUTH OF ARDMORE OKLAHOMA.  FOR A COMPLETE
DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE
(WOUS64 KWNS WOU7).

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 175...WW 176...

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 25035.


...DIAL

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 15, 8:05 PM CDT	Mesoscale Discussion	SPC	Beaver, Cimarron, Ellis, Harper, Roger Mills, Texas	2 hr
May 15, 10:53 PM CDT	Severe Thunderstorm Watch	SPC	Beaver	5 hr
May 16, 1:32 AM CDT	Mesoscale Discussion	SPC	Beaver, Ellis, Harmon	88 min
May 16, 10:55 AM CDT	Mesoscale Discussion	SPC	Beckham, Blaine, Custer, Dewey, Garfield, Grant and 9 more	95 min
May 16, 11:57 AM CDT	Mesoscale Discussion	SPC	Beckham, Greer, Harmon, Jackson, Kiowa, Tillman	2 hr
May 16, 12:01 PM CDT	Mesoscale Discussion	SPC	Cimarron, Texas	89 min
May 16, 12:58 PM CDT	Tornado Watch	SPC	Beaver, Beckham, Greer, Harmon, Jackson, Roger Mills and 2 more	6 hr
May 16, 3:04 PM CDT	Mesoscale Discussion	SPC	Grant, Kay	86 min
May 16, 3:41 PM CDT	Mesoscale Discussion	SPC	Alfalfa, Atoka, Beckham, Blaine, Bryan, Caddo and 42 more	94 min
May 16, 5:55 PM CDT	Mesoscale Discussion	SPC	Alfalfa, Beaver, Beckham, Blaine, Bryan, Caddo and 40 more	95 min

Nearby

Tornado Watches in Oklahoma, 2015 Every tornado watch in 2015

Sources

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.