Alert archive / Nebraska / Severe Thunderstorm Watches in 2001

Severe Thunderstorm Watch 101

April 7, 20014 states

The Storm Prediction Center issued this severe thunderstorm watch at Apr 7, 2001, 1:45 AM CDT for 4 states. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Apr 7, 2001, 1:45 AM CDT (06:45 UTC)
Expired: Apr 7, 2001, 7:00 AM CDT
In force: 5 hr
Issued by: the Storm Prediction Center

All 45 counties

Cherokee County, IA, Harrison County, IA, Lyon County, IA, Monona County, IA, O'Brien County, IA, Osceola County, IA, Plymouth County, IA, Sioux County, IA, Woodbury County, IA, Lincoln County, MN, Lyon County, MN, Murray County, MN, Nobles County, MN, Pipestone County, MN, Rock County, MN, Burt County, NE, Cedar County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Knox County, NE, Madison County, NE, Pierce County, NE, Platte County, NE, Stanton County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE, Bon Homme County, SD, Brookings County, SD, Clay County, SD, Hanson County, SD, Hutchinson County, SD, Kingsbury County, SD, Lake County, SD, Lincoln County, SD, McCook County, SD, Miner County, SD, Minnehaha County, SD, Moody County, SD, Turner County, SD, Union County, SD, Yankton County, SD

The radar

The Sioux Falls radar (KFSD), 107 km from the middle of the area, began a volume at 06:49 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

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

Issued	Product	Office	Counties	Lasted
Apr 7, 1:46 AM CDT	Severe Thunderstorm Warning	OAX	Burt, Cuming, Thurston	29 min
Apr 7, 2:11 AM CDT	Severe Thunderstorm Warning	FSD	Plymouth, Woodbury	34 min
Apr 7, 2:11 AM CDT	Severe Thunderstorm Warning	FSD	Dixon	34 min
Apr 7, 2:22 AM CDT	Severe Thunderstorm Warning	FSD	Lyon, Sioux	38 min
Apr 7, 2:22 AM CDT	Severe Thunderstorm Warning	FSD	Moody	38 min
Apr 7, 3:05 AM CDT	Severe Thunderstorm Warning	FSD	Lyon, O'Brien, Osceola	25 min
Apr 7, 3:29 AM CDT	Severe Thunderstorm Warning	FSD	Nobles	31 min
Apr 7, 3:51 AM CDT	Tornado Warning	FSD	Murray, Nobles	24 min
Apr 7, 4:23 AM CDT	Severe Thunderstorm Warning	FSD	Murray	37 min

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 6.8 hours before the alert went out and 156 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: 770 J/kg
Mixed-layer CIN: -60 J/kg
Mixed-layer LCL: 454 m above ground
0-6 km bulk shear: 78 kt
0-1 km storm-relative helicity: 205 m²/s²
0-3 km storm-relative helicity: 278 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.9

Open this sounding in Storm Lab

The text

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

000 
WWUS9 KMKC 070632
SEL1  

SEL1  
MKC WW 070627
IAZ000-MNZ000-NEZ000-SDZ000-071200-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 101
STORM PREDICTION CENTER NORMAN OK
127 AM CDT SAT APR 7 2001

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

   WESTERN IOWA                               
   SOUTHWEST MINNESOTA                          
   NORTHEAST NEBRASKA                           
   SOUTHEAST SOUTH DAKOTA                       

EFFECTIVE THIS SATURDAY MORNING FROM 145 AM UNTIL 700 AM 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 60 STATUTE MILES
EAST AND WEST OF A LINE FROM 30 MILES EAST OF COLUMBUS NEBRASKA TO
10 MILES NORTH NORTHEAST OF BROOKINGS 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.


DISCUSSION...SCATTERED THUNDERSTORMS HAVE DEVELOPED IN THE PAST
HOUR OVER EASTERN NEB.  THESE STORMS ARE EXPECTED TO INCREASE FOR
THE NEXT FEW HOURS AND TRACK NORTHWARD INTO PARTS OF IA/SD/MN. 
MODERATE CAPE VALUES AND VERY STRONG ENVIRONMENTAL WIND FIELDS
SUGGEST THE POTENTIAL FOR DAMAGING WINDS IN ANY SUSTAINED
CONVECTION.  LARGE HAIL WILL ALSO BE POSSIBLE IN STRONGER CELLS.

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 WcITH MAXIMUM TOPS TO 500.  MEAN STORM
MOTION VECTOR 20045.

...HART

;412,0975 442,0975 442,0953 412,0953;

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 6, 7:45 PM CDT	Tornado Watch	SPC	Adams, Buffalo, Butler, Clay, Dawson, Fillmore and 24 more	5 hr

Nearby

Severe Thunderstorm Watches in Nebraska, 2001 Severe Thunderstorm Watches in South Dakota, 2001 Severe Thunderstorm Watches in Iowa, 2001 Every severe thunderstorm watch 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.