Alert archive / Oklahoma / Severe Thunderstorm Watches in 2002
Severe Thunderstorm Watch 91
The Storm Prediction Center issued this severe thunderstorm watch at Apr 13, 2002, 7:45 AM CDT for 22 counties in Oklahoma. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 13, 2002, 7:45 AM CDT (12:45 UTC)
- Expired
- Apr 13, 2002, 1:00 PM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
All 22 counties
Bryan County, OK, Caddo County, OK, Canadian County, OK, Carter County, OK, Cleveland County, OK, Coal County, OK, Cotton County, OK, Garvin County, OK, Grady County, OK, Hughes County, OK, Jefferson County, OK, Johnston County, OK, Love County, OK, Marshall County, OK, McClain County, OK, Murray County, OK, Okfuskee County, OK, Oklahoma County, OK, Pontotoc County, OK, Pottawatomie County, OK, Seminole County, OK, Stephens County, OK
The radar
The Norman radar (KTLX), 48 km from the middle of the area, began a volume at 12:45 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.
Warnings issued inside it
4 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 13, 8:18 AM CDT | Severe Thunderstorm Warning | OUN | Cotton | 42 min |
| Apr 13, 8:43 AM CDT | Severe Thunderstorm Warning | OUN | Cotton, Tillman | 62 min |
| Apr 13, 8:54 AM CDT | Severe Thunderstorm Warning | OUN | Jefferson | 51 min |
| Apr 13, 10:12 AM CDT | Severe Thunderstorm Warning | OUN | Jefferson | 48 min |
The nearest sounding before it
Norman, OK (KOUN), launched 12:00Z, 0.8 hours before the alert went out and 45 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.
- Mixed-layer CAPE
- 77 J/kg
- Mixed-layer CIN
- -131 J/kg
- Mixed-layer LCL
- 1138 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 96 m²/s²
- 0-3 km storm-relative helicity
- 107 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
The text
As transmitted, in the capitals the NWS used until 2016.
000 WWUS20 KWNS 131229 SEL1 SPC WW 131225 OKZ000-131800- URGENT - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WATCH NUMBER 91 STORM PREDICTION CENTER NORMAN OK 725 AM CDT SAT APR 13 2002 THE STORM PREDICTION CENTER HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR PORTIONS OF SOUTH CENTRAL OKLAHOMA EFFECTIVE THIS SATURDAY MORNING AND AFTERNOON FROM 745 AM UNTIL 100 PM CDT. HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS. THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 65 STATUTE MILES EAST AND WEST OF A LINE FROM 25 MILES NORTHEAST OF OKLAHOMA CITY OKLAHOMA TO 30 MILES SOUTH SOUTHWEST OF ARDMORE OKLAHOMA. REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES. OTHER WATCH INFORMATION... CONTINUE...WW 89...WW 90... DISCUSSION...SCATTERED INTENSE THUNDERSTORMS OVER WESTERN OKLAHOMA WILL TRACK EASTWARD FOR NEXT SEVERAL HOURS. MUCAPE VALUES OF 1500- 2000 J/KG AND STEEP LAPSE RATES WILL PROMOTE HAIL IN STRONGER CELLS...WHILE INCREASING ORGANIZATION TO MCS MAY AID THREAT OF GUSTY/DAMAGING WINDS. AVIATION...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 24035. ...HART 353,0960 335,0960 335,0982 353,0982 WWUS20 KWNS 131229 SEL1 SPC WW 131225 OKZ000-131800- URGENT - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WATCH NUMBER 91 STORM PREDICTION CENTER NORMAN OK 725 AM CDT SAT APR 13 2002 THE STORM PREDICTION CENTER HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR PORTIONS OF SOUTH CENTRAL OKLAHOMA EFFECTIVE THIS SATURDAY MORNING AND AFTERNOON FROM 745 AM UNTIL 100 PM CDT. HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS. THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 65 STATUTE MILES EAST AND WEST OF A LINE FROM 25 MILES NORTHEAST OF OKLAHOMA CITY OKLAHOMA TO 30 MILES SOUTH SOUTHWEST OF ARDMORE OKLAHOMA. REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES. OTHER WATCH INFORMATION... CONTINUE...WW 89...WW 90... DISCUSSION...SCATTERED INTENSE THUNDERSTORMS OVER WESTERN OKLAHOMA WILL TRACK EASTWARD FOR NEXT SEVERAL HOURS. MUCAPE VALUES OF 1500- 2000 J/KG AND STEEP LAPSE RATES WILL PROMOTE HAIL IN STRONGER CELLS...WHILE INCREASING ORGANIZATION TO MCS MAY AID THREAT OF GUSTY/DAMAGING WINDS. AVIATION...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 24035. ...HART 353,0960 335,0960 335,0982 353,0982
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 12, 7:45 PM CDT | Severe Thunderstorm Watch | SPC | Beaver, Cimarron, Texas | 6 hr |
| Apr 12, 11:30 PM CDT | Tornado Watch | SPC | Beckham, Greer, Harmon, Roger Mills, Texas | 6 hr |
| Apr 13, 4:45 AM CDT | Severe Thunderstorm Watch | SPC | Beckham, Blaine, Comanche, Custer, Dewey, Greer and 6 more | 5 hr |
| Apr 13, 10:45 AM CDT | Severe Thunderstorm Watch | SPC | Atoka, Bryan, Carter, Choctaw, Johnston, Love and 4 more | 5 hr |
Nearby
Severe Thunderstorm Watches in Oklahoma, 2002Every severe thunderstorm watch in 2002
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.