Alert archive / Oklahoma / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 412, NWS Tulsa, OK

July 7, 1999Sequoyah County, Oklahoma

NWS Tulsa, OK issued this severe thunderstorm warning at Jul 7, 1999, 12:32 PM CDT for Sequoyah County, Oklahoma. It was in force for 43 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Jul 7, 1999, 12:32 PM CDT (17:32 UTC)
Expired
Jul 7, 1999, 1:15 PM CDT
In force
43 min
Issued by
NWS Tulsa, OK
Area
Whole counties

County Sequoyah County, OK

The nearest sounding before it

Springfield, MO (KSGF), launched 12:00Z, 5.5 hours before the alert went out and 178 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-pSkew-T log-p diagram, Springfield, MO at 12:00Z on 1999-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1053 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Springfield, MO at 12:00Z on 1999-07-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 20 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
1053 J/kg
Mixed-layer CIN
-76 J/kg
Mixed-layer LCL
748 m above ground
0-6 km bulk shear
6 kt
0-1 km storm-relative helicity
20 m²/s²
0-3 km storm-relative helicity
35 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 Tulsa, OK wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 7, 11:02 AM CDT, 1 hour 30 minutes earlier.

Area forecast discussion, Jul 7, 11:02 AM CDT, 1 hour 30 minutes before
EASTERN OKLAHOMA/NORTHWEST ARKANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
1102 AM CDT WED JUL 7 1999

WEAK COLD FRONT TO THE NORTH HAS STALLED FROM WESTERN KENTUCKY...ACROSS
EXTREME SOUTHERN MISSOURI AND INTO SOUTHEAST KANSAS.  THE FRONT
SHOULD MOVE LITTLE THE REST OF TODAY.

MORNING SOUNDINGS AROUND THE AREA SHOW THAT THE CONVECTIVE
TEMPERATURE WILL BE REACHED AGAIN THIS AFTERNOON...SO THAT ISOLATED
SHOWERS AND THUNDERSTORMS WILL OCCUR AGAIN TODAY...WITH THE MOST
NUMEROUS CELLS IN THE HIGHER TERRAIN IN SOUTHEAST OKLAHOMA AND
WESTERN ARKANSAS.  IN ADDITION...MOISTURE CONVERGENCE WAS OCCURRING
ALONG THE STALLED FRONT AT MID MORNING NEAR THE MISSOURI AND
ARKANSAS BORDERS AND THIS FRONT WILL LIKELY ALSO BE THE FOCUS FOR
ISOLATED DEVELOPMENT.  IT WAS NOTED TODAY THAT LOW-LEVEL MOISTURE
WAS A LITTLE DEEPER THAN 24 HOURS AGO...RESULTING IN FORECAST CAPES
AROUND 2000 J/KG LATER TODAY.  WITH A SLIGHTLY LOWER WET-BULB ZERO
TODAY A STORM OR TWO COULD BRIEFLY PULSE TO NEAR SEVERE LEVELS.

TEMPERATURES TODAY ARE AVERAGING OUT ABOUT AS YESTERDAY...EXCEPT IN
FAR NORTHEAST SECTIONS OF THE FORECAST AREA...HARRISON AR IS RUNNING
5 DEGREES OFF YESTERDAYS PACE.

ALL OF THIS COVERED IN THE GOING FORECAST AND WILL NOT MAKE ANY
CHANGES TO THE ZONES AT THIS TIME.

FCSTID = 8

.TUL...
AR...NONE.
OK...NONE.

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 7, 1:53 PM CDTSevere Thunderstorm WarningTSACherokee52 min
Jul 7, 2:48 PM CDTSevere Thunderstorm WarningTSAMayes, Rogers42 min
Jul 7, 3:08 PM CDTFlash Flood WarningTSAMayes, Rogers2 hr

Nearby

Severe Thunderstorm Warnings in Oklahoma, 1999Every severe thunderstorm warning in 1999

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive.