Alert archive / South Dakota / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 135, NWS Sioux Falls, SD

July 2, 1999Gregory County, South Dakota

NWS Sioux Falls, SD issued this severe thunderstorm warning at Jul 2, 1999, 10:53 PM CDT for Gregory County, South Dakota. It was in force for 62 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 2, 1999, 10:53 PM CDT (03:53 UTC)
Expired
Jul 2, 1999, 11:55 PM CDT
In force
62 min
Issued by
NWS Sioux Falls, SD
Area
Whole counties

County Gregory County, SD

The radar

The North Platte radar (KLNX), 178 km from the middle of the area, began a volume at 03:52 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.

The watch it was issued in

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

IssuedProductOfficeLasted
Jul 2, 9:30 PM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Aberdeen, SD (KABR), launched 00:00Z, 3.9 hours before the alert went out and 200 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, Aberdeen, SD at 00:00Z on 1999-07-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 235 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, Aberdeen, SD at 00:00Z on 1999-07-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 77 square meters per square second.1939587897Sfc1 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
235 J/kg
Mixed-layer CIN
-306 J/kg
Mixed-layer LCL
766 m above ground
0-6 km bulk shear
70 kt
0-1 km storm-relative helicity
77 m²/s²
0-3 km storm-relative helicity
280 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

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 Sioux Falls, SD wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 2, 9:50 PM CDT, 1 hour 3 minutes earlier.

Area forecast discussion, Jul 2, 9:50 PM CDT, 1 hour 3 minutes before
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
950 PM CDT FRI JUL 2 1999

TSTM DVLPMNT SEEMS TO BE GOING AS PLANNED BY AFTN FCSTR WITH ACTVTY
TO DO A NUMBER ON FCST AREA NEAR AND AFTR MIDNGHT. FCST WELL WORDED
WITH SVR AND HVY RAIN MENTN SO LATEST WATCH FOR WRN PART OF OUR SD
AREA...HON TO MHE TO PKS...IS THE ONLY UPDATE NEEDED NOW. PLENTY OF
RIPE AIR AVBL. EVRYBODY SEEMS TO BE EVENLY TARGETED NOW BUT WUDNT BE
SURPRISED TO SEE NRN PART OF AREA A BIT FAVORED WITH TIME...AGN AS
MENTND IN AFTN FCST. THIS MAY BE A PRETTY GOOD SOAKER AND NOT JUST
UR AVERAGE JOE TYPE OF TSTM EVENT.

.FSD...NONE
WILLIAMS

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 2, 11:21 PM CDTSevere Thunderstorm WarningFSDCharles Mix59 min
Jul 2, 11:51 PM CDTSevere Thunderstorm WarningFSDDouglas49 min
Jul 3, 12:20 AM CDTSevere Thunderstorm WarningFSDDavison, Hutchinson60 min
Jul 3, 12:20 AM CDTSevere Thunderstorm WarningFSDAurora60 min
Jul 3, 12:38 AM CDTSevere Thunderstorm WarningFSDSanborn47 min
Jul 3, 12:43 AM CDTSevere Thunderstorm WarningFSDHanson47 min
Jul 3, 1:08 AM CDTSevere Thunderstorm WarningFSDBeadle, Kingsbury62 min
Jul 3, 1:37 AM CDTSevere Thunderstorm WarningFSDBrookings, Moody48 min
Jul 3, 1:57 AM CDTSevere Thunderstorm WarningFSDLincoln, Pipestone48 min
Jul 3, 2:19 AM CDTSevere Thunderstorm WarningFSDLyon, Murray46 min
Jul 3, 2:30 AM CDTSevere Thunderstorm WarningFSDNobles35 min
Jul 3, 2:45 AM CDTSevere Thunderstorm WarningFSDCottonwood65 min

Nearby

Severe Thunderstorm Warnings in South Dakota, 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; radar from the NEXRAD Level II archive.