Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 59, NWS Norman, OK

April 11, 2001Atoka County, Bryan County, Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Apr 11, 2001, 5:30 AM CDT for Atoka County, Bryan County, Oklahoma. It was in force for 45 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: Apr 11, 2001, 5:30 AM CDT (10:30 UTC)
Expired: Apr 11, 2001, 6:15 AM CDT
In force: 45 min
Issued by: NWS Norman, OK
Area: Whole counties; the outline is the Mesonet’s reconstruction

Counties Atoka County, OK, Bryan County, OK

The radar

The Norman radar (KTLX), 156 km from the middle of the area, began a volume at 10:32 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 11, 5:34 AM CDT	Tornado F0	Wardville, OK	This is the 2nd and final county segment to the tornado which formed 4 miles southeast of Coalgate in Coal County at 0425 CST, then moved into Atoka County at 0434 CST. In Atoka County, minor roof damage was sustained to a mobile home, and numerous trees were

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 11, 3:15 AM CDT	Tornado Watch	SPC	5 hr

The nearest sounding before it

Norman, OK (KOUN), launched 00:00Z, 10.5 hours before the alert went out and 156 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: 1767 J/kg
Mixed-layer CIN: -45 J/kg
Mixed-layer LCL: 678 m above ground
0-6 km bulk shear: 63 kt
0-1 km storm-relative helicity: 114 m²/s²
0-3 km storm-relative helicity: 192 m²/s²
Significant tornado parameter: 1.0
Supercell composite: 3.8

Open this sounding in Storm Lab

The text

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

000 
WUUS54 KOUN 111031
SVROKC
OKC005-013-111115-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE NORMAN OK
530 AM CDT WED APR 11 2001

THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  ATOKA COUNTY IN SOUTHEAST OKLAHOMA
  BRYAN COUNTY IN SOUTHEAST OKLAHOMA
 
* UNTIL 615 AM CDT

* AT 528 AM CDT...DOPPLER RADAR DETECTED A LINE OF SEVERE   
  THUNDERSTORMS FROM 2 MILES WEST OF WARDVILLE TO 4 MILES WEST OF  
  UTICA...OR JUST SOUTHEAST OF DURANT... MOVING NORTHEAST AT 30 MPH.

* LOCATIONS IN THE WARNING INCLUDE ACHILLE...ATOKA...BENNINGTON...
  BLUE...BOKCHITO...CHOCKIE...DAISY...LANE...STRINGTOWN...TUSHKA...
  UTICA AND WARDVILLE

WINDS GREATER THAN 60 MPH ARE LIKELY WITHIN THIS LINE OF STORMS.

LAT...LON 3470 9624 3419 9618 3378 9643 3397 9601
          3418 9579 3459 9568 3468 9588

...SPEG.

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 Apr 11, 3:30 AM CDT, 2 hours earlier.

Area forecast discussion, Apr 11, 3:30 AM CDT, 2 hours before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
330 AM CDT WED APR 11 2001

WELL...BEYOND WHAT IS GOING ON THIS MORNING WITH SEVERE STORMS...
MAIN WORRY TODAY WILL BE WINDS. AS STRONG SFC LOW MOVES OFF TOWARD
THE NORTHEAST TODAY WITH DRY LINE/PACIFIC FRONT MOVING ACROSS THE
AREA WILL SEE STRONG SW WINDS BEHIND THE FRONT THROUGH MUCH OF THE
DAY. WILL ISSUE WIND ADVISORY FOR ENTIRE AREA TODAY. AS SFC LOW
MOVES OFF TOWARD THE NE WINDS WILL GRADUALLY DECREASE FROM SOUTH TO
NORTH BY LATE THIS AFTN AND SHOULD SEE A MORE SUBSTANTIAL DROP IN
SPEEDS THIS EVENING.

FOR PRECIP CHANCES WILL BASE POPS FOR FIRST PERIOD ON LATEST TRENDS
ON RADAR. OTHERWISE...WILL SEE MORE TRANQUIL WEATHER AFTER TODAY
GOING INTO HOLIDAY WEEKEND. APPEARS THAT AVN TRIES TO MAINTAIN SOME
SORT OF BOUNDARY FROM THIS MORNING SYSTEM TO OUR SOUTH...WHICH IT
THEN MOVES BACK NORTH OVER THE WEEKEND WITH SOME WEAK UPPER WAVES
PROGRESSING EAST ACROSS SOUTHERN US...IN FAIRLY ZONAL FLOW. THINK
AVN IS OVERDOING QPFS...BUT COULD BE SOME CHANCE WITH WAA OCCURRING
AND SOME FORCING FROM UPPER LEVELS WILL KEEP SLIGHT CHANCE TO CHANCE
SAT/SUN TIME FRAME WITH DRIER/COOLER FOR FIRST PART OF NEXT WEEK.

FIRST GUESS NUMBERS
FCSTID = 30
OKC   73  46  73  50 /  30   0   0   0
HBR   71  43  71  48 /   0   0   0   0
SPS   75  47  76  51 /   0   0   0   0
GAG   67  38  67  45 /   0   0   0   0
PNC   72  45  70  47 /  30   0s   0   0
DUA   75  48  77  53 /  30   0   0   0

.OUN...
OK...WIND ADVISORY ALL ZONES TODAY.
TX...WIND ADVISORY ALL ZONES TODAY.

In the hours before

Local storm report, Apr 11, 1:01 AM CDT, 4 hours 29 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
101 AM CDT WED APR 11 2001

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

1220 AM    4 NW FORT COBB            OK   62 MPH WIND GUST
04/11/01   CADDO                          MEASURED BY OKLAHOMA
                                          MESONET

1220 AM    3 SSE MARSHALL            OK   71 MPH WIND GUST
04/11/01   LOGAN                          REPORTED BY OKLAHOMA
                                          MESONET

LINDLEY

Local storm report, Apr 11, 2:51 AM CDT, 2 hours 39 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
251 AM CDT WED APR 11 2001

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

1235 PM    3 SSE MARSHALL            OK   73 MPH WIND GUST
04/11/01   LOGAN                          REPORTED BY OKLAHOMA
                                          MESONET

0100 AM    3 W MEDICINE PARK         OK   61 MPH WIND GUST
04/11/01   COMANCHE                       REPORTED BY OKLAHOMA
                                          MESONET

0105 AM    4 WSW WEATHERFORD         OK   58 MPH WIND GUST
04/11/01   CUSTER                         REPORTED BY OKLAHOMA
                                          MESONET

0130 AM    6 NW KAW CITY             OK   58 MPH WIND GUST
04/11/01   KAY                            REPORTED BY OKLAHOMA
                                          MESONET

0130 AM    7 SSE RED ROCK            OK   60 MPH WIND GUST
04/11/01   NOBLE                          REPORTED BY OKLAHOMA

                                       MESONET

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 11, 1:22 AM CDT	Severe Thunderstorm Warning	OUN	Dewey, Woodward	38 min
Apr 11, 1:44 AM CDT	Tornado Warning	OUN	Garvin, McClain	31 min
Apr 11, 1:56 AM CDT	Tornado Warning	OUN	Pottawatomie	34 min
Apr 11, 2:17 AM CDT	Tornado Warning	OUN	Pottawatomie	28 min
Apr 11, 2:56 AM CDT	Tornado Warning	OUN	Pottawatomie, Seminole	34 min
Apr 11, 3:58 AM CDT	Tornado Warning	OUN	Love	32 min
Apr 11, 4:41 AM CDT	Severe Thunderstorm Warning	OUN	Coal, Pontotoc	34 min
Apr 11, 5:05 AM CDT	Severe Thunderstorm Warning	OUN	Atoka, Coal, Johnston	25 min
Apr 11, 5:12 AM CDT	Severe Thunderstorm Warning	OUN	Hughes	33 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.