Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 142, NWS Tulsa, OK

May 20, 2001Osage County, Oklahoma

NWS Tulsa, OK issued this severe thunderstorm warning at May 20, 2001, 6:12 PM CDT for Osage County, Oklahoma. It was in force for 48 min. 5 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 20, 2001, 6:12 PM CDT (23:12 UTC)
Expired
May 20, 2001, 7:00 PM CDT
In force
48 min
Issued by
NWS Tulsa, OK
Area
Whole counties

County Osage County, OK

The radar

The Tulsa radar (KINX), 90 km from the middle of the area, began a volume at 23:16 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

TimeReportWhereRemark
May 20, 6:30 PM CDTTornado F0Pawhuska, OKA F0 tornado briefly touched down one mile south of Pawhuska. The tornado was video taped by a storm chaser. No damage was observed.
May 20, 6:39 PM CDTThunderstorm Wind 56 EPawhuska, OK
May 20, 6:50 PM CDTThunderstorm Wind 52 EHominy, OK
May 20, 6:50 PM CDTHail 0.75Hominy, OK
May 20, 6:57 PM CDTThunderstorm Wind 52 EWynona, 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
May 20, 5:00 PM CDTSevere Thunderstorm WatchSPC4 hr

The nearest sounding before it

Lamont, OK (KLMN), launched 12:00Z, 11.2 hours before the alert went out and 97 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, Lamont, OK at 12:00Z on 2001-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 186 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lamont, OK at 12:00Z on 2001-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 71 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
186 J/kg
Mixed-layer CIN
-106 J/kg
Mixed-layer LCL
769 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
71 m²/s²
0-3 km storm-relative helicity
125 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

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

000 
WUUS54 KTSA 202312
SVRTUL
OKC113-210000-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TULSA OK
612 PM CDT SUN MAY 20 2001

THE NATIONAL WEATHER SERVICE IN TULSA HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHEASTERN OSAGE COUNTY IN NORTHEAST OKLAHOMA

* UNTIL 700 PM CDT

* AT 612 PM CDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM 18   
MILES SOUTH OF SKIATOOK...MOVING NORTH-NORTHEAST AT 35 MPH.

* SOME LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE...SKIATOOK...
  BARNSDALL AND AVANT.

HAIL TO THE SIZE OF GOLFBALLS AND WIND GUSTS TO 65 MPH CAN BE EXPECTED 
IN THE WARNED AREA.

THIS IS A DANGEROUS STORM. IF YOU ARE NEAR ITS PATHp YOU SHOULD
PREPARE FOR VERY LARGE HAIL AND STRONG DAMAGING STRAIGHT LINE WINDS.
SEEK SHELTER IN A STURDY BUILDING AND STAY AWAY FROM WINDOWS!

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 Tulsa, OK wrote its last area forecast discussion before this severe thunderstorm warning went out at May 20, 5:40 PM CDT, 32 minutes earlier.

Area forecast discussion, May 20, 5:40 PM CDT, 32 minutes before
EASTERN OKLAHOMA/NORTHWEST ARKANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
540 PM CDT SUN MAY 20 2001

UPDATED FORECAST TO INCLUDE HEADLINE FOR SEVERE TSTORM WATCH NUMBER
256. STILL WAITING ON POSSIBLE TOR WATCH FOR WESTERN AR...WILL HAVE
TO UPDATE AGAIN WHEN AND IF IT COMES OUT. INCREASED SEVERE THREAT
WORDING IN SEVERAL ZONES GROUPS. NEW STORMS GOING UP AND INCREASING
NOW...ONE IN EAST TULSA COUNTY AND THE ONE IN CREEK COUNTY. OTHER
STORMS GOING UP IN HUGHES AND PONTOTOC COUNTIES COULD ALSO BECOME
QUITE SEVERE AS IT TAPS EXTREME INSTABILITY.

FCSTID = 26

.TSA...
AR...NONE.
OK...NONE.

In the hours before

Special weather statement, May 20, 1:05 PM CDT, 5 hours 7 minutes before
ARZ001-002-010-011-019-020-029-OKZ049-053>076-211100-

EASTERN OKLAHOMA/NORTHWEST ARKANSAS HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TULSA OK
105 PM CDT SUN MAY 20 2001

...NUMEROUS SEVERE THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND
EVENING ACROSS EASTERN OKLAHOMA AND NORTHWEST ARKANSAS...

AT MIDDAY...A LOW PRESSURE TROUGH EXTENDED SOUTH FROM A LOW PRESSURE
SYSTEM LOCATED IN SOUTH CENTRAL NEBRASKA INTO THE TEXAS PANHANDLE.
AN OUTFLOW BOUNDARY FROM THIS MORNINGS THUNDERSTORMS WAS LOCATED
ACROSS SOUTHEAST OKLAHOMA.  SOUTHERLY WINDS WERE INCREASING ACROSS
THE AREA AHEAD OF THE TROUGH WHICH WILL HELP TO MOVE THE OUTFLOW
BOUNDARY NORTHWARD THIS AFTERNOON.

IN ADDITION...AN UPPER LEVEL DISTURBANCE CURRENTLY LOCATED IN
NORTHWEST OKLAHOMA WILL CONTINUE TO MOVE EASTWARD INTO ARKANSAS BY
TONIGHT.  THIS UPPER SYSTEM IN CONJUNCTION WITH FAVORABLE UPPER
LEVEL WINDS WILL COMBINE TO PRODUCE THUNDERSTORMS ACROSS NORTHEAST
OKLAHOMA AND NORTHWEST ARKANSAS ALONG THE OUTFLOW BOUNDARY THIS
AFTERNOON.  THE THUNDERSTORMS SHOULD THEN EVOLVE INTO A LINE AND
MOVE EAST INTO ARKANSAS BY TONIGHT.

.SPOTTER ACTIVATION...
SPOTTER ACTIVATION WILL LIKELY BE REQUIRED BEFORE 4 PM ACROSS
PORTIONS OF EASTERN OKLAHOMA AND NORTHWEST ARKANSAS.

.DISCUSSION...
OUTFLOW BOUNDARY FROM THIS MORNINGS CONVECTIVE COMPLEX IS CURRENTLY
POSITIONED ACROSS SOUTHEAST OKLAHOMA FROM NEAR IDABEL TO HUGO ON
INTO SOUTH CENTRAL OKLAHOMA.  DEWPOINTS SOUTH OF THE BOUNDARY ARE IN
THE MID 70S WITH UPPER 60S TO NEAR 70 DEGREE DEWPOINTS NORTH OF THE
BOUNDARY.  LATEST FORECAST CAPE VALUES OF 3000 TO 4000 J/KG WILL BE
IN PLACE ACROSS MUCH OF THE AREA THIS AFTERNOON INTO THE EVENING
HOURS.  SOUTHERLY WINDS ARE EXPECTED TO HELP MOVE THE OUTFLOW
BOUNDARY FURTHER NORTH THIS AFTERNOON INTO EAST CENTRAL OKLAHOMA
AROUND 4 PM.  THIS BOUNDARY SHOULD PROVIDE THE FOCUS FOR
THUNDERSTORM INITIATION.  LARGE HAIL OF GOLFBALL SIZE OR LARGER WILL
BE POSSIBLE WITH THESE STORMS.  ISOLATED TORNADOES WILL ALSO BE A
THREAT MAINLY ALONG THE OUTFLOW BOUNDARY THIS AFTERNOON AND EARLY
EVENING BEFORE THE SYSTEM EVOLVES INTO LINE AND MOVES EAST INTO
ARKANSAS.

THREAT TABLE
VALID THROUGH 1200 UTC MONDAY

AREA 1...MUCH OF EASTERN OKLAHOMA AND NORTHWEST ARKANSAS
THUNDERSTORM PROBABILITY...95
SEVERE PROBABILITY IF STORMS OCCUR...90
SIGNIFICANT SEVERE PROBABILITY IF STORMS OCCUR...40

THREAT AREAS DEFINE THE GREATEST RISK.  PROBABILITIES ARE IN
PERCENT.  SIGNIFICANT SEVERE IS DEFINED AS F1 OR GREATER
WIND/TORNADO DAMAGE AND /OR GOLFBALL SIZE HAIL OR LARGER.

RELATED GRAPHICAL INFORMATION CAN BE FOUND AT: WWW.SRH.NOAA.GOV/TULSA

AN UPDATED HAZARDOUS WEATHER OUTLOOK WILL BE ISSUED AROUND 1 PM
TODAY.
Local storm report, May 20, 5:26 PM CDT, 46 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
526 PM CDT SUN MAY 20 2001

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

0450 PM    5 NW HANNA                OK    TORNADO
05/20/01   MCINTOSH                        DAMAGE REPORTED AT
                                           INDIAN NATION TURNPIKE
                                           TOLL BOOTH.

0522 PM   e 2 S STIDHAM               OK    TORNADO
05/20/01   MCINTOSH                        SAME
                                           TORNADO...CONTINUING ENE
Local storm report, May 20, 5:30 PM CDT, 42 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
530 CDT SUN MAY 20 2001

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

0450 PM    5 NW HANNA                OK    TORNADO
05/20/01   MCINTOSH                        DAMAGE REPORTED AT
                                           INDIAN NATION TURNPIKE
                                           TOLL BOOTH.

0522 PM    2 S STIDHAM               OK    TORNADO
05/20/01   MCINTOSH                        SAME
                                           TORNADO...CONTINUING ENE
Local storm report, May 20, 5:52 PM CDT, 20 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
552 PM CDT SUN MAY 20 2001

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

0548 PM    VIVIAN                    OK    1.75 INCH HAIL
05/20/01   MCINTOSH

0550 PM    2 N BROKEN ARROW          OK    1 INCH HAIL
05/20/01   TULSA
Local storm report, May 20, 6:08 PM CDT, 4 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
608 PM CDT SUN MAY 20 2001

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

K0548 PM    VIVIAN                    OK    1.75 INCH HAIL
05/20/01   MCINTOSH

0550 PM    2 N BROKEN ARROW          OK    1 INCH HAIL
05/20/01   TULSA
Local storm report, May 20, 6:11 PM CDT, 1 minute before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
611 PM CDT SUN MAY 20 2001

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

0556 PM    2 N FAIRFAX               OK    1 INCH HAIL
05/20/01   OSAGE                           REPORTED BY POLICE DEPT

0607 PM    SAND SPGS                 OK    1.75 INCH HAIL
05/20/01   TULSA                           AMATEUR RADIO REPORT
m

The office that day

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

IssuedProductOfficeCountiesLasted
May 20, 4:17 PM CDTSevere Thunderstorm WarningTSAOsage58 min
May 20, 4:24 PM CDTSevere Thunderstorm WarningTSAOkfuskee, Okmulgee51 min
May 20, 4:30 PM CDTSevere Thunderstorm WarningTSAMcIntosh60 min
May 20, 4:31 PM CDTTornado WarningTSAMcIntosh29 min
May 20, 4:56 PM CDTTornado WarningTSAMcIntosh49 min
May 20, 5:14 PM CDTSevere Thunderstorm WarningTSAOsage61 min
May 20, 5:23 PM CDTSevere Thunderstorm WarningTSACreek52 min
May 20, 5:32 PM CDTTornado WarningTSAOsage43 min
May 20, 5:45 PM CDTTornado WarningTSAMcIntosh60 min
May 20, 5:46 PM CDTSevere Thunderstorm WarningTSATulsa44 min
May 20, 5:51 PM CDTSevere Thunderstorm WarningTSARogers, Wagoner39 min
May 20, 6:02 PM CDTTornado WarningTSAPittsburg58 min
May 20, 6:11 PM CDTTornado WarningTSAHaskell, Muskogee64 min
May 20, 6:13 PM CDTSevere Thunderstorm WarningTSAPawnee62 min
May 20, 6:16 PM CDTTornado WarningTSAOsage44 min
May 20, 6:33 PM CDTSevere Thunderstorm WarningTSACraig, Mayes, Rogers57 min
May 20, 6:41 PM CDTTornado WarningTSAWashington49 min
May 20, 6:43 PM CDTSevere Thunderstorm WarningTSACreek, Tulsa62 min
May 20, 6:56 PM CDTTornado WarningTSAMayes49 min
May 20, 6:59 PM CDTSevere Thunderstorm WarningTSAOsage46 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 2001Every severe thunderstorm warning in 2001

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.