Alert archive / Oklahoma / Severe Thunderstorm Warnings in 1990

Severe Thunderstorm Warning 137, NWS Tulsa, OK

May 21, 1990Sequoyah County, Oklahoma

NWS Tulsa, OK issued this severe thunderstorm warning at May 21, 1990, 2:32 AM CDT for Sequoyah County, Oklahoma. It was in force for 58 min. 3 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, 1990, 2:32 AM CDT (07:32 UTC)
Expired
May 21, 1990, 3:30 AM CDT
In force
58 min
Issued by
NWS Tulsa, OK
Area
Whole counties

County Sequoyah 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, 2:55 AM CDTHail 0.75Sequoyah, OK
May 21, 3:13 AM CDTHail 0.75Sequoyah, OK
May 21, 3:30 AM CDTHail 1.75Sequoyah, 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

Springfield, MO (KUMN), launched 00:00Z, 7.5 hours before the alert went out and 178 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, Springfield, MO at 00:00Z on 1990-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2299 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, Springfield, MO at 00:00Z on 1990-05-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 37 square meters per square second.19395878Sfc1 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
2299 J/kg
Mixed-layer CIN
-15 J/kg
Mixed-layer LCL
1348 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
37 m²/s²
0-3 km storm-relative helicity
196 m²/s²
Significant tornado parameter
0.7
Supercell composite
7.8

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KFSM 210733
SVRFSM
ARC143-OKC135-210830-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE FORT SMITH AR
232 AM CDT MON MAY 21 1990
 
THE NATIONAL WEATHER SERVICE IN FORT SMITH HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  330 AM CDT
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN NORTHWEST ARKANSAS
 
   ...WASHINGTON COUNTY
 
 
IN NORTHEAST OKLAHOMA
 
   ...SEQUOYAH COUNTY
 
AT 233 AM WEATHER SERVICE RADAR INDICATED LINE OF SEVERE THUNDERSTORMS
FROM NEAR GRAVETTE ARKANSAS TO JUST NORTH OF WARNER OKLAHOMA. THE
STORMS ARE MOVING SOUTHEAST AT 40 MPH. DAMAGING WIND AND LARGE HAIL
ARE POSSIBLE WITH THIS LINE OF THUNDERSTORMS.
 
WHEN THUNDERSTORMS ARE OCCURRING...PEOPLE SHOULD MOVE INSIDE A
STRONG BUILDING.  DO NOT STAND BY WINDOWS.  DON'T USE TELEPHONES
OR ELECTRICAL APPLIANCES UNLESS IN AN EMERGENCY UNTIL THE STORM
HAS PASSED.  MOTORISTS SHOULD NOT DRIVE INTO LOW WATER CROSSINGS.
 
SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 55
MPH...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN.
FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR
OF YOUR HOME OR BUSINESS.  HEAVY RAINS FLOOD ROADS QUICKLY SO
DON'T DRIVE INTO AREAS WHERE WATER COVERS THE ROAD.

What forecasters said that day

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

In the hours before

Local storm report, May 20, 10:14 PM CDT, 4 hours 18 minutes before
STORM REPORT
NATIONAL WEATHER SERVICE TULSA, OK
1011 PM CDT SUN MAY 20 1990

TIME/CDT     COUNTY      EVENT

9 35 PM      OTTAWA      DIME TO NICKEL SIZE HAIL AT QUAPAW.
9 50 PM      OTTAWA      QUARTER SqIZE HAIL AT TURNPIKE TOLL BOOTH
                         ON OKLAHOMA-MISSOURI LINE. REPORTED THE HAIL
                         FALLING IN BOTH STATES.

The office that day

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

IssuedProductOfficeCountiesLasted
May 20, 9:29 PM CDTSevere Thunderstorm WarningTSAOttawa46 min
May 20, 11:26 PM CDTSevere Thunderstorm WarningTSADelaware34 min
May 20, 11:32 PM CDTSevere Thunderstorm WarningTSALeFlore58 min
May 21, 12:28 AM CDTFlash Flood WarningTSALeFlore3 hr
May 21, 12:39 AM CDTSevere Thunderstorm WarningTSALeFlore66 min
May 21, 2:27 AM CDTSevere Thunderstorm WarningTSACherokee, Muskogee48 min
May 21, 2:36 AM CDTSevere Thunderstorm WarningTSAAdair39 min
May 21, 3:27 AM CDTSevere Thunderstorm WarningTSALeFlore, Sequoyah63 min
May 21, 4:28 AM CDTSevere Thunderstorm WarningTSALeFlore62 min
May 21, 5:27 AM CDTSevere Thunderstorm WarningTSALeFlore63 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 1990Every severe thunderstorm warning in 1990

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.