Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 453, NWS Norman, OK

June 20, 2001Alfalfa County, Woods County, Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Jun 20, 2001, 9:12 PM CDT for Alfalfa County, Woods County, Oklahoma. It was in force for 48 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: Jun 20, 2001, 9:12 PM CDT (02:12 UTC)
Expired: Jun 20, 2001, 10:00 PM CDT
In force: 48 min
Issued by: NWS Norman, OK
Area: Whole counties; the outline is the Mesonet’s reconstruction

Counties Alfalfa County, OK, Woods County, OK

The radar

The Vance AFB radar (KVNX), 42 km from the middle of the area, began a volume at 02:12 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
Jun 20, 9:15 PM CDT	Hail 0.88	Capron, OK
Jun 20, 9:58 PM CDT	Hail 0.88	Cherokee, 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
Jun 20, 9:00 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Dodge City, (KDDC), launched 00:00Z, 2.2 hours before the alert went out and 162 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: 1362 J/kg
Mixed-layer CIN: -70 J/kg
Mixed-layer LCL: 956 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 164 m²/s²
0-3 km storm-relative helicity: 395 m²/s²
Significant tornado parameter: 2.2
Supercell composite: 18.3

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 Jun 20, 2:44 PM CDT, 6 hours 28 minutes earlier.

Area forecast discussion, Jun 20, 2:44 PM CDT, 6 hours 28 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
244 PM CDT WED JUN 20 2001

RATHER STRONG SHORT WAVE TROF CONTS TO DIG SEWD THIS AFTERNOON
ACROSS THE CENTRAL ROCKIES. DEEP CONVECTION IS CURRENTLY DVLPG IN
SE CO/NE NM AS FORCING FOR UVV BEGINS TO INTERACT WITH INCREASING
INSTABILITY AXIS EAST OF MOUNTAINS.  CURRENT WV/IR SAT LOOPS HINT
THAT WINDS ALOFT ON BACK SIDE OF DIGGING TROF ARE A BIT STRONGER
THAN THE LATEST ETA/RUC GUIDANCE HAVE FORECASTED.  FAIRLY DECENT
INSTABILITY AXIS HAS DEVELOPED ALONG AND NORTH OF QUASI-STATIONARY
FRONT/OUTFLOW BOUNDARY SNAKING ACROSS CENTRAL/NRN OK. THERE IS STILL
UNCERTAINTY CONCERNING CONVECTIVE EVOLUTION THRU THE
EVENING/OVERNITE..BUT FEEL POTENTIAL EXISTS FOR A FORWARD
PROPAGATING MCS TO AFFECT MUCH OF THE NRN SECTIONS OF THE AREA
OVERNITE TONITE.  LIMITING FACTORS FOR SVR SEEM TO BE INSTABILITY
AND RELATIVELY WEAK LOW LEVEL INFLOW.  HOWEVER..IF AN MCS BECOMES
HIGHLY ORGANIZED AND MOVES RAPIDLY SEWD..MCS RELATIVE INFLOW WILL BE
MAXIMIZED AND SVR WIND POTENTIAL MAY EXIST FARTHER EAST. WILL STILL
KEEP CHANCE POPS ACROSS MUCH OF SRN OK/NTEX FOR THU ALONG TRAILING
PART OF MCS/FRONT.  HOWEVER..LATEST GUIDANCE SUGGESTS SUBSIDENCE
WILL SPREAD OVR MOST OF THE FORECAST AREA BY MID TO LATE AFTERNOON
WITH LOW LEVEL ANTICYCLOGENESIS OVR SW KS.

SLIGHTLY COOLER AIRMASS WILL LINGER ACROSS THE AREA FOR 24 TO 36
HOURS BEFORE MODIFYING BACK TO NEAR NORMAL TEMPS BY THE WEEKEND.
NEXT CHANCE FOR ORGANIZED PRECIP AFTER THE FIRST AND SECOND PERIODS
APPEARS TO BE TUE/WED OF NEXT WEEK AS ANOTHER FRONT/OUTFLOW BOUNDARY
APPROACHES THE NRN SECTIONS OF THE AREA.
 MILLER

1ST CUT AT NUMBERS..
OKC   66  80  62  84 /  70  30  10   0
HBR   66  83  62  87 /  50  40  10  10
SPS   68  85  63  89 /  40  40  10  10
GAG   57  77  55  84 /  80  20  10  10
PNC   61  79  58  84 /  80  20  10   0
DUA   70  86  64  85 /  40  50  10  10

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

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 20, 9:47 PM CDT	Severe Thunderstorm Warning	OUN	Harper	43 min
Jun 20, 9:59 PM CDT	Severe Thunderstorm Warning	OUN	Alfalfa	31 min
Jun 20, 10:28 PM CDT	Severe Thunderstorm Warning	OUN	Ellis, Harper, Woodward	47 min
Jun 20, 10:30 PM CDT	Severe Thunderstorm Warning	OUN	Alfalfa	45 min
Jun 21, 2:03 PM CDT	Severe Thunderstorm Warning	OUN	Love	42 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.