Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 248, NWS Norman, OK

May 20, 2001Seminole County, Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at May 20, 2001, 6:39 PM CDT for Seminole 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: May 20, 2001, 6:39 PM CDT (23:39 UTC)
Expired: May 20, 2001, 7:30 PM CDT
In force: 51 min
Issued by: NWS Norman, OK
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Seminole County, OK

The radar

The Norman radar (KTLX), 63 km from the middle of the area, began a volume at 23:41 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
May 20, 6:43 PM CDT	Hail 1.75	Konawa, OK
May 20, 6:46 PM CDT	Hail 1	Sasakwa, 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
May 20, 3:30 PM CDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Norman, OK (KOUN), launched 12:00Z, 11.7 hours before the alert went out and 72 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 796 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: -20 m²/s²
0-3 km storm-relative helicity: 7 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

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 May 20, 3:40 PM CDT, 2 hours 59 minutes earlier.

Area forecast discussion, May 20, 3:40 PM CDT, 2 hours 59 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
340 PM CDT SUN MAY 20 2001

TSTMS BEGINNING TO RAPIDLY DEVELOP THIS AFTERNOON ACROSS OKLAHOMA IN
AREAS OF WEAK LOW LEVEL CONVERGENCE/CONFLUENCE. MEANWHILE... UPPER
TROUGH OVER WESTERN KANSAS INTO THE TX PNHDL ALSO MOVING ACROSS THE
AREA THE NEXT SEVERAL HOURS. EXPECT TSTMS TO INCREASE IN COVERAGE
THROUGH THE EVENING. MEANWHILE... STRONG COLD FRONT MOVING THROUGH
WESTERN KANSAS WILL REACH NORTHWEST OKLAHOMA AROUND MIDNIGHT...AND
MOVE THROUGH THE RED RIVER VALLEY BY MORNING. ADDITIONAL TSTMS WILL
BE POSSIBLE ALONG THE FRONT... ALTHOUGH EXTENT OF COVERAGE A LITTLE
UNCERTAIN. PASSAGE OF THE KANSAS WAVE TO THE EAST OF THE AREA AND
STABILIZATION OF AIRMASS BY CURRENT CONVECTION COULD REDUCE THE
EXTENT OF ADDITIONAL DEVELOPMENT. WILL LEAVE IN 20 TO 30 PCT CHANCE
FOR SHWRS/TSTMS BEHIND THE FRONT ON MONDAY AS A SECONDARY UPPER WAVE
BRUSHES THE AREA. STRONG JET MAX DROPPING SOUTHEAST THROUGH THE
NORTHWEST U.S. WILL DIG OUT A DEEP UPPER TROUGH OVER THE MISSISSIPPI
VALLEY BY EARLY TUESDAY. THIS FEATURE WILL MOVE VERY SLOWLY OVER THE
NEXT SEVERAL DAYS... AND AS RESULT WILL BRING SEVERAL SHOTS OF COOL
AIR TO THE REGION. BELOW NORMAL TEMPS EXPECT MOST AREAS THROUGH MUCH
OF THE WEEK.

FCSTID = 32
OKC   56  64  46  72 /  70  20   0   0
HBR   54  65  44  75 /  50  20   0   0
SPS   59  68  46  76 /  50  20   0   0
GAG   48  62  40  73 /j  50  30   0   0
PNC   52  63  44  71 /  70  30   0   0
DUA   62  68  47  75 /  70  30  10   0

.OUN...
OK...NONE.
TX...NONE.

In the hours before

Local storm report, May 20, 5:33 PM CDT, 1 hour 6 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
533 PM CDT SUN MAY 20 2001

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

0500 PM    2 NW SCOTT                OK   1.00 INCH HAIL
05/20/01   CANADIAN                       PUBLIC REPORT

0531 PM    GARBER                    OK   .75 INCH HAIL
05/20/01   GARFIELD                       AMATEUR RADIO REPORT

KT

Local storm report, May 20, 5:50 PM CDT, 49 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
550 PM CDT SUN MAY 20 2001

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

0547 PM    1 S UNION CITY            OK   .88 INCH HAIL
05/20/01   CANADIAN                       AMATEUR RADIO REPORT

0550 PM    1 S UNION CITY            OK   1.00 INCH HAIL
05/20/01   CANADIAN                       AMATEUR RADIO REPORT

KT

Local storm report, May 20, 5:55 PM CDT, 44 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
555 PM CDT SUN MAY 20 2001

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

0515 PM    DUSTIN                    OK   1.00 INCH HAIL
05/20/01   HUGHES                         REPORTED BY DUSTIN
                                          FIRE DEPARTMENT

KT

Local storm report, May 20, 6:07 PM CDT, 32 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
607 PM CDT SUN MAY 20 2001

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

0555 PM    1 S UNION CITY            OK   1.00 INCH HAIL
05/20/01   CANADIAN                       AMATEUR RADIO REPORT

0600 PM    MINCO                     OK   .75 INCH HAIL
05/20/01   GRADY                          REPORTRED BY COUNTY
                                          SHERIFFS OFFICE

0607 PM    3 N MUSTANG               OK   .75 INCH HAIL
05/20/01   CANADIAN                       AMATEUR RADIO REPORT

KT

Local storm report, May 20, 6:28 PM CDT, 11 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
628 PM CDT SUN MAY 20 2001

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

0618 PM    4 ENE VANOSS              OK   1.75 INCH HAIL
05/20/01   PONTOTOC                       REPORTED BY COUNTY EOC

0629 PM    POCASSET                  OK   .75 INCH HAIL
05/20/01   GRADY                          AMATEU1R RADIO REPORT

KT

Local storm report, May 20, 6:39 PM CDT, 0 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
639 PM CDT SUN MAY 20 2001

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

0638 PM    BYNG                      OK   1.00 INCH HAIL
05/20/01   PONTOTOC                       REPORTED BY BYNG FIRE
                                          DEPARTMENT

KT

The office that day

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

Issued	Product	Office	Counties	Lasted
May 19, 7:26 PM CDT	Flash Flood Warning	OUN	Stephens	3 hr
May 20, 3:47 AM CDT	Severe Thunderstorm Warning	OUN	Cotton	43 min
May 20, 4:28 AM CDT	Severe Thunderstorm Warning	OUN	Jefferson	62 min
May 20, 3:26 PM CDT	Severe Thunderstorm Warning	OUN	Seminole	49 min
May 20, 3:34 PM CDT	Severe Thunderstorm Warning	OUN	Pottawatomie	41 min
May 20, 3:44 PM CDT	Severe Thunderstorm Warning	OUN	Hughes	46 min
May 20, 3:53 PM CDT	Severe Thunderstorm Warning	OUN	Blaine, Dewey	52 min
May 20, 4:07 PM CDT	Tornado Warning	OUN	Hughes	38 min
May 20, 4:09 PM CDT	Severe Thunderstorm Warning	OUN	Kay	51 min
May 20, 4:12 PM CDT	Tornado Warning	OUN	Seminole	33 min
May 20, 4:40 PM CDT	Tornado Warning	OUN	Hughes	50 min
May 20, 4:42 PM CDT	Severe Thunderstorm Warning	OUN	Garfield, Kingfisher	63 min
May 20, 4:42 PM CDT	Severe Thunderstorm Warning	OUN	Caddo, Canadian	63 min
May 20, 4:50 PM CDT	Severe Thunderstorm Warning	OUN	Pontotoc, Seminole	40 min
May 20, 5:29 PM CDT	Severe Thunderstorm Warning	OUN	Hughes	46 min
May 20, 5:40 PM CDT	Severe Thunderstorm Warning	OUN	Canadian, Grady	50 min
May 20, 6:23 PM CDT	Severe Thunderstorm Warning	OUN	Pontotoc	52 min
May 20, 6:34 PM CDT	Tornado Warning	OUN	Pontotoc	26 min
May 20, 6:56 PM CDT	Severe Thunderstorm Warning	OUN	Hughes	49 min
May 20, 6:59 PM CDT	Severe Thunderstorm Warning	OUN	Coal, Pontotoc	46 min
May 19, 7:02 PM CDT	Severe Thunderstorm Warning	OUN	Wilbarger	43 min
May 19, 7:14 PM CDT	Severe Thunderstorm Warning	OUN	Baylor	31 min
May 19, 7:25 PM CDT	Severe Thunderstorm Warning	OUN	Archer	50 min
May 19, 8:00 PM CDT	Tornado Warning	OUN	Archer	30 min
May 19, 8:04 PM CDT	Severe Thunderstorm Warning	OUN	Wichita	26 min
May 19, 8:29 PM CDT	Tornado Warning	OUN	Archer, Clay	31 min
May 19, 8:59 PM CDT	Severe Thunderstorm Warning	OUN	Clay	46 min
May 20, 2:03 AM CDT	Severe Thunderstorm Warning	OUN	Wilbarger	57 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 2001 Every 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.