Alert archive / Oklahoma / Tornado Warnings in 1987

Tornado Warning 8, NWS Norman, OK

May 21, 1987Logan County, Oklahoma

NWS Norman, OK issued this tornado warning at May 21, 1987, 5:35 PM CDT for Logan County, Oklahoma. It was in force for 40 min. 2 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
May 21, 1987, 5:35 PM CDT (22:35 UTC)
Expired
May 21, 1987, 6:15 PM CDT
In force
40 min
Issued by
NWS Norman, OK
Area
Whole counties

County Logan County, OK

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

What was reported inside it

TimeReportWhereRemark
May 21, 5:44 PM CDTHail 1Logan, OK
May 21, 6:24 PM CDTHail 1.75Logan, OK

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.

The nearest sounding before it

Ok Cty/Will Rgrs, OK (KOKC), launched 12:00Z, 10.6 hours before the alert went out and 59 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-pSkew-T log-p diagram, Ok Cty/Will Rgrs, OK at 12:00Z on 1987-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2809 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Ok Cty/Will Rgrs, OK at 12:00Z on 1987-05-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 81 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
2809 J/kg
Mixed-layer CIN
-100 J/kg
Mixed-layer LCL
976 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
81 m²/s²
0-3 km storm-relative helicity
98 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KOKC 212235
TOROKC
OKC083-212315-
 
BULLETIN - EBS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE OKLAHOMA CITY OK
535 PM CDT THU MAY 21 1987
 
THE NATIONAL WEATHER SERVICE HAS ISSUED A TORNADO WARNING
EFFECTIVE UNTIL  615 PM CDT FOR PEOPLE IN THE FOLLOWING COUNTY...
 
IN CENTRAL OKLAHOMA
          ...SOUTHERN LOGAN
 
AT 535 PM CDT RADAR INDICATED A POSSIBLE TORNADO 2 MILES SOUTH OF
GUTHRIE MOVING TOWARD THE EAST AT 5 MILES PER HOUR. THIS STORM IS
CAPABLE OF PRODUCING HAIL LARGER THAN GOLFBALLS AND WINDS IN EXCESS
OF 60 MILES PER HOUR.
 
IF YOU ARE IN THE PATH OF A TORNADO...THE SAFEST PLACE IS A
BASEMENT.  GET UNDER A WORKBENCH OR PIECE OF STURDY FURNITURE.
IF NO BASEMENT IS AVAILABLE.<..SEEK SHELTER IN AN INTERIOR ROOM
SUCH AS A CLOSET ON THE LOWEST FLOOR.  USE BLANKETS...PILLOWS...
OR CUSHIONS TO COVER YOUR BODY.  AVOID WINDOWS.

What forecasters said that day

The local office's own words before this tornado warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

In the hours before

Special weather statement, May 21, 12:03 PM CDT, 5 hours 32 minutes before
OKLAHOMA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE OKLAHOMA CITY OK
1200 PM CDT THU MAY 21 1987

A MODERATE RISK OF SEVERE THUNDERSTORMS EXISTS OVER PORTIONS OF
NORTHERN AND EASTERN OKLAHOMA THIS AFTERNOON AND TONIGHT. THE MODERATE
RISK AREA COVERS THAT PORTION OF OKLAHOMA NORTH AND EAST OF A PONCA
CITY...OKLAHOMA CITY...FORT SMITH AR LINE. THERE IS A SLIGHT RISK
OF SEVERE THUNDERSTORMS OVER PORTIONS OF SOUTHERN OKLAHOMA. THE SLIGHT
RISK AREA LIES EAST OF AN ALTUS...OKLAHOMA CITY LINE AND WEST OF A
DURANT...FORT SMITH AR LINE...AND BORDERS THE MODERATE RISK AREA TO THE
NORTH.

AT MIDDAY...A COLD FRONT HAS PUSHED ACROSS NORTHWEST PORTIONS OF
OKLAHOMA AND CURRENTLY LIES ALONG A PONCA CITY-HOLLIS LINE. THIS FRONT
CONTINUES TO PUSH SLOWLY SOUTHEASTWARD. A DRY LINE EXTENDS FROM THE
FRONT NEAR OKLAHOMA CITY SOUTHWARD INTO NORTH TEXAS TO THE WEST OF
ABILENE. THE LOCATION WHERE THE FRONT AND DRYLINE INTERSECT IS CALLED
A 'TRIPLE POINT' BY METEOROLOGISTS...AND IS OFTEN A FOCUS FOR SEVERE
WEATHER DEVELOPMENT. LOW LEVEL MOISTURE IS SURGING NORTHWARD AHEAD
OF THE FRONT AND DRYLINE...ACROSS THE SOUTHEASTERN TWO-THIRDS OF THE
STATE...WHERE THE AIRMASS IS EXTREMELY UNSTABLE.

THE POTENTIAL EXISTS FOR A SIGNIFICANT OUTBREAK OF SEVERE WEATHER OVER
PORTIONS OF THE STATE THIS AFTERNOON AND TONIGHT. THUNDERSTORM
DEVELOPMENT IS EXPECTED TO BEGIN BY MID-AFTERNOON...MOST LIKELY
ALONG THE FRONT AND/OR DRYLINE. THE TRIPLE POINT IS EXPECTED TO MOVE
SLOWLY NORTHEASTWARD ALONG THE FRONT...MOVING INTO NORTH CENTRAL
OR NORTHEAST OKLAHOMA BY LATE AFTERNOON. THE BEST CHANCE FOR SEVERE
WEATHER EXISTS NEAR THE TRIPLE POINT...BUT SEVERE ACTIVITY CANNOT
BE RULED OUT ANYWHERE IN OKLAHOMA NEA?R THE FRONT OR DRYLINE.

CIVIL DEFENSE AND STORM SPOTTER GROUPS IN THE OUTLOOK AREA SHOULD
REMAIN ALERT AND BE READY FOR ACTIVATION LATER THIS AFTERNOON.
LATER INFORMATION WILL BE INCLUDED IN THE UPDATED OUTLOOK TO BE ISSUED
AROUND 3 PM.
Special weather statement, May 21, 3:18 PM CDT, 2 hours 17 minutes before
OKLAHOMA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE OKLAHOMA CITY OK
315 PM CDT THU MAY 21 1987

A MODERATE RISK OF SEVERE THUNDERSTORMS EXISTS OVER PORTIONS OF
NORTHERN AND EASTERN OKLAHOMA THIS AFTERNOON AND TONIGHT. THE MODERATE
RISK AREA COVERS THAT PORTION OF OKLAHOMA NORTH AND EAST OF A PONCA
CITY...OKLAHOMA CITY...FORT SMITH AR LINE. THERE IS A SLIGHT RISK
OF SEVERE THUNDERSTORMS OVER PORTIONS OF SOUTHERN OKLAHOMA. THE SLIGHT
RISK AREA LIES EAST OF AN ALTUS...OKLAHOMA CITY LINE AND WEST OF A
DURANT...FORT SMITH AR LINE...AND BORDERS THE MODERATE RISK AREA TO THE
NORTH.

AT MIDAFTERNOON...A STATIONARY FRONT EXTENDS ALONG A LINE FROM PONCA
CITY TO CHILDRESS TX. A DRY LINE EXTENDS FROM THE FRONT NEAR OKLAHOMA
CITY SOUTHWARD INTO NORTH TEXAS TO THE WEST OF ABILENE. THE LOCATION
WHERE THE FRONT AND DRYLINE INTERSECT IS CALLED A 'TRIPLE POINT' BY
METEOROLOGISTS...AND IS OFTEN A FOCUS FOR SEVERE WEATHER DEVELOPMENT.
LOW LEVEL MOISTURE COVERS THE SOUTHEASTERN TWO-THIRDS OF THE STATE AHEAD
OF THE FRONT AND DRYLINE.

UPPER AIR INFORMATION RECEIVED AROUND 2 PM FROM SOUTH CENTRAL
OKLAHOMA INDICATES THE ATMOSPHERE IS NOT QUITE AS EXPLOSIVELY
UNSTABLE AS IT WAS EARLIER TODAY. HOWEVER...THUNDERSTORM ACTIVITY
IS STARTING TO FIRE UP ALONG THE COLD FRONT TO OUR NORTHEAST IN
MISSOURI...AND TO OUR SOUTH IN TEXAS ALONG THE DRYLINE. SUFFICIENT
INSTABILITY STILL EXISTS OVER OKLAHOMA...AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP ALONG THE COLD FRONT AND/OR DRYLINE BY 4 PM.

THE POTENTIAL REMAINS FOR A SIGNIFICANT OUTBREAK OF SEVERE
WEATHER OVER PORTIONS OF THE STATE THIS AFTERNOON AND TONIGHT.
THE BEST CHANCE FOR SEVERE WEATHER EXISTS NEAR THE TRIPLE POINT...BUT
SEVERE ACTuIVITY CANNOT BE RULED OUT ANYWHERE IN OKLAHOMA NEAR THE FRONT
OR DRYLINE.

CIVIL DEFENSE AND STORM SPOTTER GROUPS IN THE OUTLOOK AREA SHOULD
EXPECT TO BE ACTIVATED BY LATE AFTERNOON.
Special weather statement, May 21, 5:25 PM CDT, 10 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WICHITA FALLS TX
525 PM CDT THU MAY 21 1987

AT 520 PM THE WICHITA FALLS NATIONAL WEATHER RADAR SHOWED A BAND
OF THUNDERSTORMS A FEW PRODUCING VERY HEAVY RAIN DEVELOPING FROM VERNON
TO JUST NORTH OF ABILENE. THE HEAVIEST RAINS WERE FALLING JUST WEST
OF LAKE KEMP AND TO THE SOUTHWEST OF SEYMOUR.

THESE STORMS WERE MOVING TO THE NORTHEAST AT 15 TO 20 MPH.

AT PRESENT NO SEVERE WEATHER WAS INDICATED IN ASSOCIATION WITH THESE
STORMS. HOWEVER THE POTENTIAL FOR SEVERE WEATHER DOES EXIST ACROSS
THE AREA THIS AFTERNOON. THE STORMS COULD POSSIBLY INTENSITY.
RESIDENTS ARE ADVISED TO STAY TUNED TO NOAA WEATHER RADIO OR COMMERCIAL
RADIO AND T.V. FOR LATER STATEMENTS AND POSSIBLE WARNINGS.
Special weather statement, May 21, 5:26 PM CDT, 9 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WICHITA FALLS TX
525 PM CDT THU MAY 21 1987

AT 520 PM THE WICHITA FALLS NATIONAL WEATHER RADAR SHOWED A BAND
OF THUNDERSTORMS A FEW PRODUCING VERY HEAVY RAIN DEVELOPING FROM VERNON
TO JUST NORTH OF ABILENE. THE HEAVIEST RAINS WERE FALLING JUST WEST
OF LAKE KEMP AND TO THE SOUTHWEST OF SEYMOUR.

THESE STORMS WERE MOVING TO THE NORTHEAST AT 15 TO 20 MPH.

AT PRESENT NO SEVERE WEATHER WAS INDICATED IN ASSOCIATION WITH THESE
STORMS. HOWEVER THE POTENTIAL FOR SEVERE WEATHER DOES EXIST ACROSS
THE AREA THIS AFTERNOON. THE STORMS COULD POSSIBLY INTENSIFY.
RESIDENTS ARE ADVISED TO STAY TUNED TO NOAA WEATHER RADIO OR COMMERCIAL
RADIO AND T.V. FOR LATER STATEMENTS AND POSSIBLE WARNINGS.

The office that day

Everything else NWS Norman, OK issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 20, 7:19 PM CDTSevere Thunderstorm WarningOUNWashita26 min
May 20, 8:48 PM CDTSevere Thunderstorm WarningOUNCanadian27 min
May 21, 4:49 PM CDTSevere Thunderstorm WarningOUNLogan, Oklahoma56 min
May 21, 4:59 PM CDTTornado WarningOUNLogan31 min
May 21, 5:23 PM CDTSevere Thunderstorm WarningOUNBlaine, Canadian, Kingfisher52 min
May 21, 5:29 PM CDTSevere Thunderstorm WarningOUNCanadian, Oklahoma46 min
May 21, 6:03 PM CDTSevere Thunderstorm WarningOUNCaddo, Canadian57 min
May 21, 6:13 PM CDTSevere Thunderstorm WarningOUNLincoln, Logan, Oklahoma47 min

Nearby

Tornado Warnings in Oklahoma, 1987Every tornado warning in 1987Tornadoes in 1987

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.