Alert archive / South Dakota / Severe Thunderstorm Warnings in 1999
Severe Thunderstorm Warning 186, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 20, 1999, 10:51 PM CDT for Miner County, South Dakota. It was in force for 34 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
- Aug 20, 1999, 10:51 PM CDT (03:51 UTC)
- Expired
- Aug 20, 1999, 11:25 PM CDT
- In force
- 34 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Whole counties
County Miner County, SD
The radar
The Sioux Falls radar (KFSD), 86 km from the middle of the area, began a volume at 03:53 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 nearest sounding before it
Aberdeen, SD (KABR), launched 00:00Z, 3.9 hours before the alert went out and 116 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.
- Mixed-layer CAPE
- 223 J/kg
- Mixed-layer CIN
- -201 J/kg
- Mixed-layer LCL
- 1223 m above ground
- 0-6 km bulk shear
- 43 kt
- 0-1 km storm-relative helicity
- 165 m²/s²
- 0-3 km storm-relative helicity
- 314 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.2
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 Aug 20, 9:16 PM CDT, 1 hour 35 minutes earlier.
Area forecast discussion, Aug 20, 9:16 PM CDT, 1 hour 35 minutes before
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 845 PM CDT FRI AUG 20 1999 CONVECTIVE TRENDS OVERNIGHT ARE THE MAIN CONCERN FOR POTENTIAL EVENING UPDATES. SURFACE FEATURES THIS EVENING CONSIST OF A WEAK SURFACE LOW IN SCNTRL SD NR MURDO...WITH A WARM FRONT SSEWRD THRU CNTRL NEBRASKA. PROFILERS VERIFY GENERAL RUC TREND...OF DEVELOPING SRLY TO SWRLY LLJ ACRS CNTRL NEBR. FAIR AMOUNT OF CAPPED INSTABILITY...WITH LATEST LAPS ANALYSIS RIGHT IN LINE WITH SATELLITE BASED CAPE FROM 1500 TO 2500 J/KG...BUT CIN OF 200 TO 400 J/KG. NATURE OF STORMS TO NW ARE ELEVATED...WHICH MAKE LESS OF AN ISSUE...BUT CINS MUCH LOWER FROM SCNTRL INTO SWRN SD...WHICH IS LIKELY WHY DEVELOPMENT HAS BEEN CONTINUING ON THE WEST FLANK OF THE CONVECTIVE CLUSTER. WL HAVE TO DO SOME REFINING OF TSRA TIMING...AND WL LIKELY INCREASE CERTAINTY ESPLY N AND E OF KFSD. WOULD HAVE TO BELIEVE THAT THREAT FOR SEVERE WEATHER SHUD INCREASE FOR A TIME NEXT 3 TO 6 HRS WITH LLJ. LOOKS LIKE SOONER THAN LATER...SO WL HAVE TO CUT THIS OFF. .FSD...NONE CHAPMAN
The office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 20, 8:36 PM CDT | Severe Thunderstorm Warning | FSD | Beadle, Kingsbury | 49 min |
| Aug 20, 10:07 PM CDT | Severe Thunderstorm Warning | FSD | Beadle | 33 min |
| Aug 20, 10:26 PM CDT | Severe Thunderstorm Warning | FSD | Kingsbury | 34 min |
| Aug 20, 11:33 PM CDT | Severe Thunderstorm Warning | FSD | Kingsbury | 32 min |
| Aug 20, 11:47 PM CDT | Tornado Warning | FSD | Kingsbury | 33 min |
| Aug 21, 2:27 AM CDT | Severe Thunderstorm Warning | FSD | Lake, Moody | 33 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.