Alert archive / Oklahoma / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 367, NWS Norman, OK

June 18, 1998Garvin County, Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Jun 18, 1998, 5:21 PM CDT for Garvin County, Oklahoma. It was in force for 54 min. 1 report came from inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties, with what was reported inside it.

The facts

Issued: Jun 18, 1998, 5:21 PM CDT (22:21 UTC)
Expired: Jun 18, 1998, 6:15 PM CDT
In force: 54 min
Issued by: NWS Norman, OK
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Garvin County, OK

The radar

The Norman radar (KTLX), 73 km from the middle of the area, began a volume at 22:21 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 was reported inside it

Time	Report	Where	Remark
Jun 18, 5:26 PM CDT	Hail 0.88	Foster, 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.

The nearest sounding before it

Norman, OK (KOUN), launched 12:00Z, 10.4 hours before the alert went out and 60 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: 1939 J/kg
Mixed-layer CIN: -299 J/kg
Mixed-layer LCL: 1074 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 436 m²/s²
0-3 km storm-relative helicity: 495 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.7

Open this sounding in Storm Lab

The text

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

849 
WUUS1 KOKC 182223 RRA
SVROKC
OKC049-182315-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE NORMAN OK
521 PM CDT THU JUN 18 1998

THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
     GARVIN COUNTY IN SOUTHEAST OKLAHOMA

* UNTIL 615 PM CDT

* AT 513 PM CDT DOPPLER RADAR INDICATED A LINE OF SEVERE 
  THUNDERSTORMS FROM FOSTER TO VELMA...MOVING NORTHEAST AT 30 MILES 
  PER HOUR.

* LOCATIONS IN THE WARNING INCLUDE WYNNEWOOD...WHITEBEAD...PURDY...
  PERNELL...PAULS VALLEY...PAOLI...MAYSVILLE...FOSTER...ELMORE CITY
  AND ANTIOCH

HAIL UP TO THE SIZE OF NICKELS AND WIND GUSTS TO 55 MPH ARE LIKELY. 
SEEK SHELTER INDOORS...AWAY FROM WINDOWS...AND AVOID ELECTRICAL 
APPLIANCES AND TELEPHONES.

LAT...LON 3470 9762 3468 9755 3453 9753 3452 9717
          3462 9722 3469 9700 3486 9709 3486 9746

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.

NWS Norman, OK wrote its last area forecast discussion before this severe thunderstorm warning went out at Jun 18, 3:55 PM CDT, 1 hour 26 minutes earlier.

Area forecast discussion, Jun 18, 3:55 PM CDT, 1 hour 26 minutes before

FPUS3 KOKC 182100
AFDOKC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
355 PM CDT THU JUN 18 1998

FRONTAL BOUNDARY SHOWS UP WELL ON VISIBLE IMAGERY...EXTENDING FROM
NEAR KSWO TO KTIK TO KFDR. IT APPEARS THAT SURFACE BASED CONVECTION
MAY BE UNDERWAY IN LINCOLN/ERN PAYNE COUNTY AS RAPIDLY DEVELOPING
STORMS ARE SHOWING UP ON KTLX. WILL BE A CLOSE CALL AS TO WHETHER OR
NOT THEY GO SEVERE IN OUR AREA OR WAIT UNTIL THEY GET INTO THE TULSA
CWA.

THICKER AREA OF CU AND WEAK ECHOES ARE ALSO SHOWING UP OVER THE
WICHITA FALLS AREA. INSTABILITY WILL LIKELY HAVE TO BATTLE CAP A BIT
LONGER BEFORE STORMS START FIRING IN THIS AREA...HOWEVER...THINK THE
STORMS WILL DEVELOP WITHIN THE NEXT FEW HOURS. EXPECT PRECIP TO
BECOME MORE WIDESPREAD ACROSS THE E CNTRL ZONES TONIGHT AS CAP
CONTINUES TO WEAKEN.

FOR THE ZONES WILL KEEP POPS NEAR AND EAST OF CURRENT FRONTAL
POSITION. ALTHOUGH MODELS DISAGREE ON LOCATION WHERE FRONT WILL
STALL AND WASH OUT...THEY ALL AGREE THAT IT WILL STALL AND WASH OUT
THROUGH TOMORROW AFTERNOON. WINDS WILL BE KIND OF SQUIRRELLY
TONIGHT...BUT EXPECT THEM TO GO LIGHT AND VARIABLE OVER MOST OF THE
AREA AFTER MIDNIGHT. LEE TROF DEVELOPS DURING THE AFTERNOON
FRIDAY...GRADUALLY BRINGING SLY FLOW AREAWIDE. WILL CARRY LOW POPS
TOMORROW OVER THE SOUTHEAST FOR LINGERING ACTIVITY FROM
TONIGHT...AND WILL ALSO CARRY LOW POPS IN THE WEST FOR LATE TOMORROW
AFTERNOON FOR POSSIBLE TSTM DEVELOPMENT ALONG DRYLINE.

EXTENDED MODELS SHOW CHANCE OF PRECIP THROUGH TUESDAY AS ANOTHER
FRONT STALLS ACROSS THE AREA AND SLOWLY LIFTS NWD AS A WARM FRONT.
LOW CONFIDENCE IN DRASTIC CHANGES IN NOGAPS 850 TEMPS WITH LATEST
RUN...SO WILL NOT CHANGE TEMPS TOO MUCH FROM PREVIOUS FORECAST.

FCSTID = 17/MMT
OKC   70  95  72  96 /  20  10  20  20
HBR   65  99  73 100 /   0  20  20  20
SPS   72  97  74  99 /  20  20  20  20
GAG   58  95  67  97 /   0  20  20  20
PNC   68  95  72  97 /  10  10  20  20
DUA   75  92  76  95 /  40  20  20  20

.OUN...
OK...SVR TSTM WATCH UNTIL 10 PM ZONES 20-26-28>32.
TX...NONE.

In the hours before

Special weather statement, Jun 18, 12:25 PM CDT, 4 hours 56 minutes before

OKZ004>048-050>052-TXZ083>090-191200-

THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE NORMAN OK
1225 PM CDT THU JUN 18 1998

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON ACROSS
PORTIONS OF CENTRAL AND SOUTHERN OKLAHOMA...SOUTH AND EAST OF A LINE
FROM PERRY TO EL RENO TO CHICKASHA TO DUNCAN.  OVERNIGHT THE SLIGHT
RISK OF SEVERE THUNDERSTORMS WILL BE CONFINED TO SOUTHEAST OF A LINE
FROM TECUMSEH TO ARDMORE.  DAMAGING WIND GUSTS WILL BE THE MAIN
THREAT...ALTHOUGH LARGE HAIL IS ALSO POSSIBLE.

DISCUSSION...A COLD FRONT EXTENDING FROM PONCA CITY TO JUST WEST OF
EL RENO TO JUST EAST OF LAWTON EARLY THIS AFTERNOON WILL CONTINUE
MOVE SOUTHEAST ACROSS OKLAHOMA THIS AFTERNOON.  THE FRONT SHOULD BE
LOCATED SOMEWHERE IN THE VICINITY OF A TECUMSEH TO ARDMORE LINE BY
LATE EVENING.  ALONG AND AHEAD OF THE FRONT...DEWPOINTS IN THE LOWER
TO MIDDLE 70S ARE PROVIDING FOR A VERY UNSTABLE ATMOSPHERE.
HOWEVER...AS WAS THE CASE YESTERDAY...A STRONG CAP REMAINS IN PLACE
ACROSS OKLAHOMA.  A DISTURBANCE MOVING ACROSS SOUTHERN KANSAS MAY
PROVIDE ENOUGH MID LEVEL COOLING TO ALLOW THE CAP TO BREAK DURING
THE AFTERNOON ALONG AND AHEAD OF THE COLD FRONT.  IF THUNDERSTORMS ARE
ABLE TO DEVELOP...A FEW OF THEM MAY BECOME SEVERE.  VERY DRY AIR IN
THE MID LEVELS WILL RESULT IN THE MAIN THREAT BEING DAMAGING WIND
GUSTS...BUT THE POSSIBLILTY OF SUPERCELLS PRODUCING LARGE HAIL AND
AN ISOLATED TORNADO CANNOT BE RULED OUT.

SPOTTER GROUPS IN CENTRAL AND SOUTHEAST OKLAHOMA SHOULD BE PREPARED
FOR POSSIBLE ACTIVATION THIS AFTERNOON AND TONIGHT.
 MILLER

Special weather statement, Jun 18, 12:25 PM CDT, 4 hours 56 minutes before

OKZ004>048-050>052-TXZ083>090-191200-

THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE NORMAN OK
1225 PM CDT THU JUN 18 1998

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON ACROSS
PORTIONS OF CENTRAL AND SOUTHERN OKLAHOMA...SOUTH AND EAST OF A LINE
FROM PERRY TO EL RENO TO CHICKASHA TO DUNCAN.  OVERNIGHT THE SLIGHT
RISK OF SEVERE THUNDERSTORMS WILL BE CONFINED TO SOUTHEAST OF A LINE
FROM TECUMSEH TO ARDMORE.  DAMAGING WIND GUSTS WILL BE THE MAIN
THREAT...ALTHOUGH LARGE HAIL IS ALSO POSSIBLE.

DISCUSSION...A COLD FRONT EXTENDING FROM PONCA CITY TO JUST WEST OF
EL RENO TO JUST EAST OF LAWTON EARLY THIS AFTERNOON WILL CONTINUE
MOVE SOUTHEAST ACROSS OKLAHOMA THIS AFTERNOON.  THE FRONT SHOULD BE
LOCATED SOMEWHERE IN THE VICINITY OF A TECUMSEH TO ARDMORE LINE BY
LATE EVENING.  ALONG AND AHEAD OF THE FRONT...DEWPOINTS IN THE LOWER
TO MIDDLE 70S ARE PROVIDING FOR A VERY UNSTABLE ATMOSPHERE.
HOWEVER...AS WAS THE CASE YESTERDAY...A STRONG CAP REMAINS IN PLACE
ACROSS OKLAHOMA.  A DISTURBANCE MOVING ACROSS SOUTHERN KANSAS MAY
PROVIDE ENOUGH MID LEVEL COOLING TO ALLOW THE CAP TO BREAK DURING
THE AFTERNOON ALONG AND AHEAD OF THE COLD FRONT.  IF THUNDERSTORMS ARE
ABLE TO DEVELOP...A FEW OF THEM MAY BECOME SEVERE.  VERY DRY AIR IN
THE MID LEVELS WILL RESULT IN THE MAIN THREAT BEING DAMAGING WIND
GUSTS...BUT THE POSSIBLILTY OF SUPERCELLS PRODUCING LARGE HAIL AND
AN ISOLATED TORNADO CANNOT BE RULED OUT.

SPOTTER GROUPS IN CENTRAL AND SOUTHEAST OKLAHOMA SHOULD BE PREPARED
FOR POSSIBLE ACTIVATION THIS AFTERNOON AND TONIGHT.
 MILLER

Local storm report, Jun 18, 5:06 PM CDT, 15 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
506 PM CDT THU JUN 18 1998

TIME (CDT) .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0502 PM    COMANCHTE                  OK   .88 INCH HAIL
06/18/98   STEPHENS                       REPORTED BY NWS COOP
                                          OBSERVER.

TL

Local storm report, Jun 18, 5:06 PM CDT, 15 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
506 PM CDT THU JUN 18 1998

TIME (CDT) .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0502 PM    COMANCHTE                  OK   .88 INCH HAIL
06/18/98   STEPHENS                       REPORTED BY NWS COOP
                                          OBSERVER.

TL

Local storm report, Jun 18, 5:15 PM CDT, 6 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
515 PM CDT THU JUN 18 1998

TIME (CDT) .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0510 PM    6 W VELMA                 OK   .75 INCH HAIL
06/18/98   STEPHENS                       REPORTED BY VELMA P.D.

TL

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 17, 7:16 PM CDT	Severe Thunderstorm Warning	OUN	Greer, Jackson	44 min
Jun 17, 7:43 PM CDT	Severe Thunderstorm Warning	OUN	Kiowa, Washita	47 min
Jun 18, 4:52 PM CDT	Severe Thunderstorm Warning	OUN	Stephens	53 min
Jun 18, 6:43 PM CDT	Severe Thunderstorm Warning	OUN	Jefferson, Stephens	47 min
Jun 18, 6:56 PM CDT	Severe Thunderstorm Warning	OUN	Carter, Garvin, Murray	49 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 1998 Every severe thunderstorm warning in 1998

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; radar from the NEXRAD Level II archive.