Alert archive / Oklahoma / Severe Thunderstorm Warnings in 1990

Severe Thunderstorm Warning 141, NWS Tulsa, OK

May 21, 1990LeFlore County, Sequoyah County, Oklahoma

NWS Tulsa, OK issued this severe thunderstorm warning at May 21, 1990, 3:27 AM CDT for LeFlore County, Sequoyah County, Oklahoma. It was in force for 63 min. 1 report 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, 3:27 AM CDT (08:27 UTC)
Expired: May 21, 1990, 4:30 AM CDT
In force: 63 min
Issued by: NWS Tulsa, OK
Area: Whole counties

Counties LeFlore County, OK, 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

Time	Report	Where	Remark
May 21, 3:30 AM CDT	Hail 1.75	Sequoyah, 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, 8.5 hours before the alert went out and 207 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: 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 210828
SVRFSM
OKC135-079-210930-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE FORT SMITH AR
327 AM CDT MON MAY 21 1990
 
THE NATIONAL WEATHER SERVICE IN FORT SMITH HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  430 AM CDT
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN NORTHEAST OKLAHOMA
 
   ...SEQUOYAH COUNTY
 
IN SOUTHEAST OKLAHOMA
 
   ...LE FLORE COUNTY
 
AT 325 RADAR SHOWED A LINE OF SEVERE THUNDERSTORMS FROM HUNTSVILLE
ARKANSAS TO QUINTON OKLAHOMA OR 25 MILE NORTHEAST OF MC ALESTER.
THE STORMS ARE MOVING TO THE SOUTHEAST AT 30 MPH. DIME SIZED HAIL
HAS BEEN REPORTED IN VIAN OKLAHOMA.
 
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, 5 hours 13 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.

Issued	Product	Office	Counties	Lasted
May 20, 9:29 PM CDT	Severe Thunderstorm Warning	TSA	Ottawa	46 min
May 20, 11:26 PM CDT	Severe Thunderstorm Warning	TSA	Delaware	34 min
May 20, 11:32 PM CDT	Severe Thunderstorm Warning	TSA	LeFlore	58 min
May 21, 12:28 AM CDT	Flash Flood Warning	TSA	LeFlore	3 hr
May 21, 12:39 AM CDT	Severe Thunderstorm Warning	TSA	LeFlore	66 min
May 21, 2:27 AM CDT	Severe Thunderstorm Warning	TSA	Cherokee, Muskogee	48 min
May 21, 2:32 AM CDT	Severe Thunderstorm Warning	TSA	Sequoyah	58 min
May 21, 2:36 AM CDT	Severe Thunderstorm Warning	TSA	Adair	39 min
May 21, 4:28 AM CDT	Severe Thunderstorm Warning	TSA	LeFlore	62 min
May 21, 5:27 AM CDT	Severe Thunderstorm Warning	TSA	LeFlore	63 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 1990 Every 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.