Alert archive / Oklahoma / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 86, NWS Tulsa, OK

April 20, 1997McIntosh County, Oklahoma

NWS Tulsa, OK issued this severe thunderstorm warning at Apr 20, 1997, 7:09 PM CDT for McIntosh County, Oklahoma. It was in force for 51 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: Apr 20, 1997, 7:09 PM CDT (00:09 UTC)
Expired: Apr 20, 1997, 8:00 PM CDT
In force: 51 min
Issued by: NWS Tulsa, OK
Area: Whole counties

County McIntosh County, OK

The radar

The Tulsa radar (KINX), 90 km from the middle of the area, began a volume at 00:11 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
Apr 20, 7:50 PM CDT	Hail 0.88	Checotah, OK
Apr 20, 8:05 PM CDT	Hail 1	Checotah, 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.

Issued	Product	Office	Lasted
Apr 20, 3:45 PM CDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Norman, OK (KOUN), launched 00:00Z, 0.2 hours before the alert went out and 158 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: 490 J/kg
Mixed-layer CIN: -106 J/kg
Mixed-layer LCL: 2384 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 5 m²/s²
0-3 km storm-relative helicity: 14 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KTUL 210010 RRA
SVRTUL
OKC091-210100-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TULSA OK
709 PM CDT SUN APR 20 1997
 
THE NATIONAL WEATHER SERVICE IN TULSA HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  800 PM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN EAST CENTRAL OKLAHOMA
 
   ...MCINTOSH COUNTY
 
AT 707 PM...RADAR SHOWED A SEVERE THUNDERSTORM NEAR HITCHITA. THE STORM
WAS MOVING EAST AT 30 MPH. HITCHITA IS IN THE PATH OF THIS STORM. OTHER
INTENSIFYING STORMS WERE MOVING INTO WESTERN MCINTOSH COUNTY.
 
HAIL TO THE SIZE OF NICKELS AND WIND GUSTS TO 60 MPH CAN BE EXPECTED
IN THE WARNED AREA.
 
A TORNADO WATCH IS ALSO IN EFFECT FOR THE WARNED AREA.  REMEMBER...
SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES WITH
LITTLE OR NO ADVANCE WARNING.  REMAIN CALM BUT BE ALERT TO RAPIDLY
CHANGING WEATHER CONDITIONS.
 
KEEP TUNED TO THIS STATION FOR THE LATEST WEATHER BULLETINS.

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 Apr 20, 3:36 PM CDT, 3 hours 33 minutes earlier.

Area forecast discussion, Apr 20, 3:36 PM CDT, 3 hours 33 minutes before

EASTERN OKLAHOMA/NORTHWEST ARKANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
335 PM CDT SUN APR 20 1997

SFC LO CONTG TO DEEPEN THRU THE AFTN AND LTCD JUST NW EMP KS AT 20Z.
SFC FNT/TROF EXTNDG FRM LO DOWN TO OSAGE/PAWNEE CONTIES IN NWRN PART
OF FA...THEN ON TWRD S-CNTL OK.  GUSTY SWLY SFC WNDS CONTG OUT AHD
OF BNDRY WITH DEWPTS IN THE 50S.  AMS HAS CONTD TO BCM INCRSLY
UNSTBL..BUT MOISTR RMNS SHALLOW.  MAIN THREAT OF BIG STMS THIS EVNG
STILL APPEARS TO BE SE KS/SW MO CLOSER TO SFC LO WHICH COULD THEN
AFFECT FAR NE OK AND NW AR.  WL CARRY HIGHEST POPS THOSE LCTNS...BUT
WL CONT TO MAINTAIN AT LEAST LO POPS ACRS REMAINDER OF FA AHD OF
ADVANCING FNT/TROF.  SFC LO WL CONT TO TRACK TO THE ESE OR SE ENDING
THREAT OF PRECIP MOST AREAS BY LATE EVNG.  HWVR SRN PORTION OF FNT
COULD HANG UP OVR SRN ZNS.

THRU REMAINING PDS UNSETTLED WX WL CONT THRU MUCH OF THE WEEK
AS WL RMN BASICALLY IN A RATHER QUICK MOVG NWLY FLOW PTRN.  PTRN
WL BE A LTL LESS AMPLIFIED ACRS THE COUNTRY...BUT WL STILL CONT TO
SEE SERIES OF S/WVS MOVG THRU THE PLNS WITH TIMING PBLMS BTWN
VARIOUS MDLS.  FOR NOW WL TEND TO BROADBRUSH SLGT CHC/CHC POPS
THRU LATER PDS.

PRELIM NUMBERS:  TUL 53/73/51/70 2233  BVO 49/73/48/70 1233
                 FSM 54/75/50/71 4233  FYV 49/68/47/68 5233
...04...         MLC 54/77/51/71 3233  IDB 57/76/50/72 4233
                                       BYV 47/68/45/68 5233
.TUL...
OK...NONE.
AR...NONE.

In the hours before

Local storm report, Apr 20, 6:01 PM CDT, 1 hour 8 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
601 PM CDT SUN APR 20 1997

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

0538 PM    2 SW WELCH                OK   .88 INCH HAIL
04/20/97   CRAIG

0550 PM    NARCISSA                  OK   .88 INCH HAIL
04/20/97   OTTAWA

0554 PM    3 S MIAMI                 OK   1 INCH HAIL
04/20/97   OTTAWA

Local storm report, Apr 20, 7:06 PM CDT, 3 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
706 PM CDT SUN APR 20 1997

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

0705 PM    2 E TULLAHASSEE           OK   1 INCH HAIL
04/20/97   WAGONER

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 20, 7:01 PM CDT	Severe Thunderstorm Warning	TSA	Cherokee	59 min
Apr 20, 7:26 PM CDT	Severe Thunderstorm Warning	TSA	Muskogee	49 min
Apr 20, 8:00 PM CDT	Severe Thunderstorm Warning	TSA	McIntosh	30 min
Apr 20, 8:13 PM CDT	Severe Thunderstorm Warning	TSA	Cherokee, Muskogee	47 min
Apr 20, 8:54 PM CDT	Severe Thunderstorm Warning	TSA	Sequoyah	51 min
Apr 20, 9:11 PM CDT	Severe Thunderstorm Warning	TSA	Muskogee	34 min
Apr 20, 9:39 PM CDT	Severe Thunderstorm Warning	TSA	Sequoyah	36 min
Apr 20, 10:13 PM CDT	Severe Thunderstorm Warning	TSA	LeFlore, Sequoyah	47 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 1997 Every severe thunderstorm warning in 1997

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.