

000 

WWUS20 KWNS 221902

SEL4

SPC WW 221902

IAZ000-MOZ000-NEZ000-230200-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 164

NWS STORM PREDICTION CENTER NORMAN OK

155 PM CDT SUN APR 22 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       WESTERN IOWA

       NORTHWEST MISSOURI

       NORTHEAST NEBRASKA



EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 155 PM UNTIL 900

PM CDT.



TORNADOES...HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 60 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 25 MILES NORTH NORTHWEST OF

STORM LAKE IOWA TO 20 MILES WEST OF CHILLICOTHE MISSOURI.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU4).



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 162...WW 163...



DISCUSSION...TSTMS NOW IN FAR ERN NEB ARE ON LEADING EDGE OF UPR

VORT MAX.  AS UPR SYSTEM CONTINUES ENE...CLEARING/LOW LEVEL MOISTURE

INFLOW SHOULD FURTHER DESTABILIZE REGION IMMEDIATELY AHEAD OF STORMS

SWD INTO NW MO.  WIND PROFILES ARE MOST SUPPORTIVE OF SUPERCELLS IN

SRN PART OF WW...WHERE 50-60 KT MID LEVEL SPEED MAX IS PRESENT ON S

SIDE OF VORT.  IF DESTABILIZATION/CONVERGENCE CAN OVERCOME LOW LEVEL

CIN...A FEW SUPERCELLS WITH HAIL/WIND AND POSSIBLE TORNADOES COULD

FORM.  FARTHER N...DEEP SHEAR IS LESS FAVORABLE FOR SUSTAINED

SUPERCELLS... BUT ENHANCED LOW LEVEL VEERING JUST E VORT-ASSOCIATED

SFC LOW MAY ENHANCE TORNADO POTENTIAL IN NW IA.



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

SURFACE AND ALOFT TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 50 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

400. MEAN STORM MOTION VECTOR 22040.





...CORFIDI

