Tornado Watch 355

Issued

May 15, 1998, 3:00 PM CDT (20:00 UTC)

Expired

May 15, 1998, 9:00 PM CDT

In force

6 hr

Issued by

the Storm Prediction Center

957 
WWUS9 KMKC 151917
SEL5  
MKC WW 151917
MNZ000-IAZ000-160200-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 355
STORM PREDICTION CENTER NORMAN OK
217 PM CDT FRI MAY 15 1998

THE STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

   SOUTHERN MINNESOTA                          
   IOWA                               

EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 300 PM UNTIL 900
PM CDT.

TORNADOES...HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 95 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS ALONG AND 105 STATUTE MILES EAST AND WEST
OF A LINE FROM 45 MILES NORTHEAST OF REDWOOD FALLS MINNESOTA TO 10
MILES EAST OF LAMONI IOWA.

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND 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...THIS TORNADO WATCH REPLACES SEVERE
THUNDERSTORM WATCH NUMBER 353.  WATCH NUMBER 353 WILL NOT BE IN
EFFECT AFTER 300 PM CDT.  CONTINUE...WW 354...

DISCUSSION...SEVERE THUNDERSTORMS ARE CONTINUING TO SPREAD NWD
ACROSS WRN/CENTRAL IA INTO SRN MN...WHILE OTHER STORMS OVER ERN NE
ARE MOVING NEWD TOWARD WRN IA.  THUNDERSTORMS ARE LOCATED AHEAD OF
STRONG UPPER VORTICITY MAX LIFTING NEWD ACROSS ERN NE...IN REGION
OF ENHANCED LOW LEVEL CONVERGENCE NEAR SURFACE LOW AND OLD OUTFLOW
BOUNDARY.  EXTREMELY LARGE SURFACE PRESSURE FALLS THAT HAVE
PERSISTED AHEAD OF THE LOW ARE NOW OVER IA AND SRN MN...
CONTRIBUTING TO BACKING LOW LEVEL WINDS.  THIS IS RESULTING IN
INCREASED VERTICAL SHEAR WITH GREATER POTENTIAL FOR SUPERCELL
DEVELOPMENT DURING THE LATE AFTERNOON AND EVENING HOURS. 


AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES.  EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 80 KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. 
MEAN STORM MOTION VECTOR 20045.


...WEISS

450,0921 403,0914 403,0954 450,0963

Tornado Watches in Iowa, 1998Tornado Watches in Minnesota, 1998Tornado Watches in Wisconsin, 1998Every tornado watch in 1998

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.