Alert archive / South Dakota / Severe Thunderstorm Watches in 1998

Severe Thunderstorm Watch 784

August 19, 19986 counties in Minnesota; 17 counties in South Dakota

The Storm Prediction Center issued this severe thunderstorm watch at Aug 19, 1998, 5:45 PM CDT for 6 counties in Minnesota; 17 counties in South Dakota. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Aug 19, 1998, 5:45 PM CDT (22:45 UTC)
Expired
Aug 19, 1998, 9:00 PM CDT
In force
3 hr
Issued by
the Storm Prediction Center
All 23 counties

Chippewa County, MN, Lac qui Parle County, MN, Lincoln County, MN, Lyon County, MN, Pipestone County, MN, Yellow Medicine County, MN, Bon Homme County, SD, Brookings County, SD, Charles Mix County, SD, Davison County, SD, Deuel County, SD, Douglas County, SD, Hamlin County, SD, Hanson County, SD, Hutchinson County, SD, Kingsbury County, SD, Lake County, SD, McCook County, SD, Miner County, SD, Minnehaha County, SD, Moody County, SD, Turner County, SD, Yankton County, SD

The radar

The Sioux Falls radar (KFSD), 60 km from the middle of the area, began a volume at 22:44 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.

Warnings issued inside it

8 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Aug 19, 5:47 PM CDTSevere Thunderstorm WarningFSDKingsbury33 min
Aug 19, 6:12 PM CDTSevere Thunderstorm WarningFSDMiner, Sanborn33 min
Aug 19, 6:23 PM CDTSevere Thunderstorm WarningFSDKingsbury47 min
Aug 19, 6:32 PM CDTSevere Thunderstorm WarningFSDCharles Mix, Douglas33 min
Aug 19, 6:44 PM CDTSevere Thunderstorm WarningMPXChippewa, Lac qui Parle, Swift61 min
Aug 19, 6:49 PM CDTSevere Thunderstorm WarningFSDMiner, Sanborn46 min
Aug 19, 7:15 PM CDTSevere Thunderstorm WarningFSDLake30 min
Aug 19, 7:22 PM CDTSevere Thunderstorm WarningMPXYellow Medicine38 min

The nearest sounding before it

Aberdeen, SD (KABR), launched 12:00Z, 10.8 hours before the alert went out and 146 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 12:00Z on 1998-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 323 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 12:00Z on 1998-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 42 square meters per square second.193958Sfc1 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
323 J/kg
Mixed-layer CIN
-312 J/kg
Mixed-layer LCL
1668 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
42 m²/s²
0-3 km storm-relative helicity
96 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

408 
WWUS9 KMKC 192228
SEL4  
MKC WW 192228
MNZ000-SDZ000-200200-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 784
STORM PREDICTION CENTER NORMAN OK
528 PM CDT WED AUG 19 1998

THE STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

   EXTREME SOUTHWEST MINNESOTA                          
   EAST CENTRAL AND SOUTHEAST SOUTH DAKOTA                       

EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 545 PM UNTIL
900 PM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 50 STATUTE MILES
EAST AND WEST OF A LINE FROM 35 MILES WEST OF YANKTON SOUTH DAKOTA
TO 60 MILES EAST NORTHEAST OF WATERTOWN SOUTH DAKOTA.

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. 
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.

OTHER WATCH INFORMATION...  CONTINUE...WW 783...

DISCUSSION...LINE OF STRONG/SEVERE STORMS HAS DEVELOPED ALONG
CONVERGENCE BOUNDARY FROM NEAR WATERTOWN SD INTO EXTREME NORTHERN
NEBRASKA.  AIR MASS OVER THE AREA IS VERY MOIST AND UNSTABLE WITH
DEW POINTS NEAR 70F AND SURFACE-BASED CAPE OF 3000-3500 J/KG.  VAD
WIND PROFILE FROM KFSD SHOWS VEERING WINDS IN THE LOWEST 3 KM AND
SPEEDS AROUND 30 KT...INDICATING SUFFICIENT SHEAR TO MAINTAIN
THREAT OF SEVERE STORMS.  SHORT WAVE TROUGH MOVING NEWD ACROSS
CENTRAL SOUTH DAKOTA WILL ENHANCE CONVECTIVE POTENTIAL INTO THE
EVENING HOURS.


AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70
KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550.  MEAN STORM
MOTION VECTOR 24030.


...WEISS

425,0990 450,0965 450,0945 425,0970

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 19, 3:15 PM CDTSevere Thunderstorm WatchSPCAitkin, Anoka, Benton, Big Stone, Carlton, Cass and 26 more6 hr

Nearby

Severe Thunderstorm Watches in South Dakota, 1998Severe Thunderstorm Watches in Minnesota, 1998Every severe thunderstorm watch in 1998

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.