

465 

WWUS20 KWNS 012001

SEL0

SPC WW 012001

IAZ000-MNZ000-NDZ000-SDZ000-020300-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 220

NWS STORM PREDICTION CENTER NORMAN OK

300 PM CDT TUE MAY 1 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       NORTHWEST IOWA

       CENTRAL AND SOUTHERN MINNESOTA

       FAR SOUTHEAST NORTH DAKOTA

       EASTERN SOUTH DAKOTA



EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 300 PM UNTIL

1000 PM CDT.



TORNADOES...HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 70 STATUTE

MILES EAST AND WEST OF A LINE FROM 40 MILES EAST OF YANKTON SOUTH

DAKOTA TO 40 MILES NORTHEAST OF ALEXANDRIA MINNESOTA.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU0).



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...CONTINUE...WW 217...WW 218...WW 219...



DISCUSSION...TSTMS CURRENTLY DEVELOPING ACROSS WARM SECTOR WITHIN

CONFLUENT LOW-LEVEL FLOW SHOULD CONTINUE TO INCREASE IN COVERAGE AND

INTENSITY AS REGION IS GLANCED BY MIDLEVEL SHORTWAVE TROUGH AND JET

STREAK MOVING THROUGH THE RED RIVER VALLEY.  THE COMBINATION OF

STEEP LAPSE RATES AND MODEST BOUNDARY LAYER MOISTURE ARE RESULTING

IN A MODERATELY UNSTABLE ENVIRONMENT THIS AFTERNOON WITH MLCAPE OF

1000-1500 J/KG.  WHEN COUPLED WITH STEADILY STRENGTHENING LOW AND

DEEP-LAYER SHEAR...SETUP WILL BECOME INCREASINGLY FAVORABLE FOR

SUPERCELLS CAPABLE OF LARGE HAIL...DAMAGING WINDS...AND A FEW

TORNADOES.



AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

500. MEAN STORM MOTION VECTOR 25030.





...MEAD

