Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 461, NWS Norman, OK

September 18, 2002Blaine County, Dewey County, Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Sep 18, 2002, 7:55 PM CDT for Blaine County, Dewey County, Oklahoma. It was in force for 50 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: Sep 18, 2002, 7:55 PM CDT (00:55 UTC)
Expired: Sep 18, 2002, 8:45 PM CDT
In force: 50 min
Issued by: NWS Norman, OK
Area: Counties, with a storm outline in the text

Counties Blaine County, OK, Dewey County, OK

The radar

The Vance AFB radar (KVNX), 104 km from the middle of the area, began a volume at 00:59 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
Sep 18, 8:30 PM CDT	Thunderstorm Wind	Longdale, OK	A ten inch diameter tree was downed.
Sep 18, 8:40 PM CDT	Thunderstorm Wind	Homestead, OK	Power lines were downed.

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.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The watch it was issued in

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

Issued	Product	Office	Lasted
Sep 18, 3:30 PM CDT	Severe Thunderstorm Watch	SPC	6 hr
Sep 18, 7:00 PM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Lamont, OK (KLMN), launched 00:00Z, 0.9 hours before the alert went out and 135 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: 3017 J/kg
Mixed-layer CIN: -71 J/kg
Mixed-layer LCL: 1725 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 186 m²/s²
0-3 km storm-relative helicity: 316 m²/s²
Significant tornado parameter: 1.0
Supercell composite: 7.7

Open this sounding in Storm Lab

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 Sep 18, 3:48 PM CDT, 4 hours 7 minutes earlier.

Area forecast discussion, Sep 18, 3:48 PM CDT, 4 hours 7 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
348 PM CDT WED SEP 18 2002

WITH SURFACE FRONT AND UPPER SYSTEM APPROACHING... CHANCES LOOK GOOD
FOR RAIN IN MOST AREAS TONIGHT.  ALTHOUGH WE ARE STARTING OFF WITH A
BIT OF A CAP TO OVERCOME... THINK THAT CAP WILL BE LESS OF AN ISSUE
AS THE UPPER TROF MOVES TOWARD THE AREA.  AM IMPRESSED WITH THE
AMOUNT OF CONVECTION DEVELOPING IN NEW MEXICO AND WEST TEXAS AND
WILL SEE HOW THINGS DEVELOP THIS EVENING AS THIS LIFT HITS BETTER
MOISTURE OVER OKLAHOMA.  WILL KEEP VERY HIGHS POPS MOST AREAS
TONIGHT.  THE MODELS HAVE BEEN SLOWING THE PROGRESS OF THE UPPER
SYSTEM AND WITH LINGERING MOISTURE BEHIND THE FRONT HAVE INCREASED
THE POPS THURSDAY AND INTO THURSDAY NIGHT.  BUMPED MAX TEMPERATURES
DOWN FOR FRIDAY AS 850 MB TEMPERATURES REMAIN COOL.

MADE FEW CHANGES TO THE EXTENDED.

...SPEG.
OKC   68  74  54  78 /  80  50  20  10
HBR   65  72  52  79 /  80  20  10   0
SPS   69  79  55  83 /  70  40   0   0
GAG   57  64  48  77 /  70  30  10  10
PNC   66  72  52  77 /  80  50  30  10
DUA   72  81  57  81 /  40  70  40  10

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

In the hours before

Local storm report, Sep 18, 7:19 PM CDT, 36 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
719 PM CDT WED SEP 18 2002

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

0655 PM    3 E VERA                  TX   60 MPH WIND GUST
09/18/02   KNOX                           REPORTED BY SPOTTER

0715 PM    4 W ARAPAHO               OK   1.25 INCH HAIL
09/18/02   CUSTER                         REPORTED BY SPOTTER

TY

Local storm report, Sep 18, 7:23 PM CDT, 32 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
723 PM CDT WED SEP 18 2002

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

0650 PM    5 SW BUTLER               OK   80 MPH WIND GUST
09/18/02   CUSTER                         REPORTED BY MESONET.

TY

Local storm report, Sep 18, 7:34 PM CDT, 21 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
734 PM CDT WED SEP 18 2002

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

0605 PM    MANGUM                    OK   WIND DAMAGE
09/18/02   GREER                          WINDOWS BLOWN OUT. NUMEROUS
                                          TREES DOWNED. ROOF DAMAGE.
                                          REPORTED BY MANGUM EOC.

TY

Local storm report, Sep 18, 7:46 PM CDT, 9 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
746 PM CDT WED SEP 18 2002

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

0730 PM    JEFFERSON                 OK   60 MPH WIND GUST
09/18/02   GRANT                          NWS COOP OBSERVER

FM

Local storm report, Sep 18, 7:51 PM CDT, 4 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
751 PM CDT WED SEP 18 2002

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

0725 PM    5 NE SEYMOUR              TX   60 MPH WIND GUST
09/18/02   BAYLOR                         REPORTED BY AMATEUR RADIO.

0730 PM    5 NE SEYMOUR              TX   60 MPH WIND GUST
09/18/02   BAYLOR                         REPORTED BY AMATEUR RADIO.

TY

Local storm report, Sep 18, 7:55 PM CDT, 0 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
755 PM CDT WED SEP 18 2002

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

0725 PM    3 N PUTNAM                OK   74 MPH WIND GUST
09/18/02   DEWEY                          REPORTED BY MESONET.

TY

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 18, 7:11 PM CDT	Severe Thunderstorm Warning	OUN	Grant, Kay	64 min
Sep 18, 7:13 PM CDT	Severe Thunderstorm Warning	OUN	Custer	32 min
Sep 18, 7:31 PM CDT	Severe Thunderstorm Warning	OUN	Garfield, Major	44 min
Sep 18, 8:01 PM CDT	Severe Thunderstorm Warning	OUN	Caddo, Canadian, Grady	44 min
Sep 18, 8:12 PM CDT	Severe Thunderstorm Warning	OUN	Garfield, Grant, Kay, Major, Noble	48 min
Sep 18, 8:30 PM CDT	Severe Thunderstorm Warning	OUN	Kingfisher	45 min
Sep 18, 8:44 PM CDT	Severe Thunderstorm Warning	OUN	Canadian	46 min
Sep 18, 8:48 PM CDT	Severe Thunderstorm Warning	OUN	Blaine, Custer	42 min
Sep 18, 9:02 PM CDT	Severe Thunderstorm Warning	OUN	Garfield, Kay, Noble	58 min
Sep 18, 9:10 PM CDT	Severe Thunderstorm Warning	OUN	Kingfisher	50 min
Sep 18, 9:22 PM CDT	Severe Thunderstorm Warning	OUN	Custer, Washita	23 min
Sep 18, 9:24 PM CDT	Flash Flood Warning	OUN	Kay	3 hr
Sep 18, 9:28 PM CDT	Severe Thunderstorm Warning	OUN	Canadian	47 min
Sep 18, 9:36 PM CDT	Severe Thunderstorm Warning	OUN	Jackson	39 min
Sep 18, 9:55 PM CDT	Severe Thunderstorm Warning	OUN	Kingfisher, Logan	50 min
Sep 18, 10:01 PM CDT	Severe Thunderstorm Warning	OUN	Canadian, Oklahoma	59 min
Sep 18, 10:13 PM CDT	Severe Thunderstorm Warning	OUN	Tillman	47 min
Sep 18, 10:25 PM CDT	Severe Thunderstorm Warning	OUN	Payne	50 min
Sep 18, 10:37 PM CDT	Severe Thunderstorm Warning	OUN	Noble	23 min
Sep 18, 10:58 PM CDT	Severe Thunderstorm Warning	OUN	Canadian, Oklahoma	47 min
Sep 18, 11:08 PM CDT	Severe Thunderstorm Warning	OUN	Payne	37 min
Sep 18, 11:18 PM CDT	Severe Thunderstorm Warning	OUN	Cleveland, Grady, McClain	57 min
Sep 19, 6:09 AM CDT	Severe Thunderstorm Warning	OUN	Atoka, Coal, Johnston	51 min
Sep 18, 7:28 PM CDT	Severe Thunderstorm Warning	OUN	Baylor	47 min
Sep 18, 8:16 PM CDT	Severe Thunderstorm Warning	OUN	Archer	44 min
Sep 18, 8:53 PM CDT	Severe Thunderstorm Warning	OUN	Wichita	52 min
Sep 18, 10:32 PM CDT	Severe Thunderstorm Warning	OUN	Baylor, Knox	28 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 2002 Every severe thunderstorm warning in 2002

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.