

000 

WWUS20 KWNS 030658

SEL8

SPC WW 030658

IAZ000-NEZ000-SDZ000-031400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 428

NWS STORM PREDICTION CENTER NORMAN OK

155 AM CDT TUE JUN 3 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN IOWA

       EASTERN NEBRASKA

       SOUTHEAST SOUTH DAKOTA



EFFECTIVE THIS TUESDAY MORNING FROM 155 AM UNTIL 900 AM CDT.



HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 85

STATUTE MILES EAST AND WEST OF A LINE FROM 55 MILES NORTHEAST OF

YANKTON SOUTH DAKOTA TO 20 MILES SOUTH OF TEKAMAH NEBRASKA.  FOR

A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU8).



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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY

DO PRODUCE TORNADOES.



OTHER WATCH INFORMATION...CONTINUE...WW 427...



DISCUSSION...SCTD TSTMS/POSSIBLE SUPERCELLS EXPECTED TO PERSIST

ALONG AXIS OF RICH 925-850 MB MOISTURE IN WEAK WAA/ASCENT ALONG SRN

STREAM JET.  50 KT DEEP WLY SHEAR AND STEEP MID-LVL LAPSE RATES

SUGGEST CONTINUED RISK FOR LARGE HAIL AND POSSIBLY LOCALLY DMGG WIND

AS STORMS DEVELOP SE ALONG SEGMENT OF WNW/ESE-ORIENTED ELEVATED WARM

FRONT THROUGH LATER THIS MORNING.  AN ADDITIONAL WW MAY BE NEEDED S

OF THIS WW INTO S CNTRL/SE NEB AND SW IA LATER THIS MORNING AS WAA

FOCUSES MORE STRONGLY SWD WITH TIME.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 30025.





...CORFIDI

