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Severe Thunderstorm Watch 681
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WW0681 Radar
Hazard Tornadoes EF2+ Tornadoes
Likelihood Low Very Low
Severe Wind 65 kt+ Wind
Moderate Low
Severe Hail 2"+ Hail
Moderate Moderate

Note:  The expiration time in the watch graphic is amended if the watch is replaced, cancelled or extended.
Note: Click for Watch Status Reports.
   SEL1
   
   URGENT - IMMEDIATE BROADCAST REQUESTED
   SEVERE THUNDERSTORM WATCH NUMBER 681
   NWS STORM PREDICTION CENTER NORMAN OK
   655 AM CDT SUN AUG 9 2009
   
   THE NWS STORM PREDICTION CENTER HAS ISSUED A
   SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
   
          WESTERN AND CENTRAL IOWA
          A SMALL PART OF NORTHEAST NEBRASKA
   
   EFFECTIVE THIS SUNDAY MORNING AND AFTERNOON FROM 655 AM UNTIL 200
   PM CDT.
   
   HAIL TO 2.5 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 65
   STATUTE MILES NORTH AND SOUTH OF A LINE FROM 20 MILES SOUTH
   SOUTHWEST OF SIOUX CITY IOWA TO 30 MILES SOUTH OF WATERLOO IOWA. 
   FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
   OUTLINE UPDATE (WOUS64 KWNS WOU1).
   
   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 680...
   
   DISCUSSION...SLIGHTLY ELEVATED TSTMS/SUPERCELLS NOW IN E CNTRL NEB
   MAY CONTINUE E AND POSSIBLY INTENSIFY AS THEY ENCOUNTER INCREASINGLY
   SHALLOW LAYER OF POST-FRONTAL AIR E OF THE MO RVR /REF MCD 1835/. 
   35-40 KT ESELY CLOUD LAYER SHEAR AND DEGREE OF INSTABILITY ABOVE
   SHALLOW NEAR-SFC LAYER SUGGEST POTENTIAL FOR LARGE HAIL AND...WITH
   TIME... FORWARD-PROPAGATING BOWING SEGMENTS WITH HIGH WIND.  DEEP
   UNIDIRECTIONAL FLOW WITH MOISTURE/INSTABILITY FEED IN THE UPWIND
   DIRECTION FURTHER SUGGESTS POTENTIAL FOR BACK-BUILDING/REGENERATIVE
   STORMS AFTER LEAD ACTIVITY HAS MOVED THROUGH.
   
   AVIATION...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 550. MEAN STORM
   MOTION VECTOR 26030.
   
   
   ...CORFIDI
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