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566 

WWUS20 KWNS 090009

SEL2

SPC WW 090009

IAZ000-NEZ000-090700-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 592

NWS STORM PREDICTION CENTER NORMAN OK

705 PM CDT SUN AUG 8 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN...CENTRAL...AND NORTHERN IOWA

       EASTERN NEBRASKA



EFFECTIVE THIS SUNDAY NIGHT AND MONDAY MORNING FROM 705 PM UNTIL

200 AM CDT.



HAIL TO 1.5 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 60

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 50 MILES NORTH OF

GRAND ISLAND NEBRASKA TO 65 MILES SOUTHEAST OF MASON CITY IOWA.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU2).



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 587...WW 588...WW

589...WW 590...WW 591...



DISCUSSION...COMPLEX MCS HAS EVOLVED OVER NE NEB THIS EVE.  AREA

WIND AND THERMODYNAMIC FIELDS SUGGEST THAT NORTHERN PART OF SYSTEM

SHOULD TRACK MAINLY ESE ACROSS IA TOWARD I-35...WHILE WRN/SRN PART

OF MCS TURNS MORE TO THE RIGHT AND TRACKS SE INVOF THE MO RVR VLY AS

LLJ VEERS AND STRENGTHENS LATER THIS EVE.  DEEP SHEAR IS

MODEST...AND UPR LVL FORCING FOR ASCENT APPEARS NEGLIGIBLE.  BUT

COMBINATION OF STRONG INSTABILITY/RICH MOISTURE AND STEEP LOW LVL

LAPSE RATES SUGGEST A CONTINUED RISK FOR DMGG WIND AND POSSIBLY SVR

HAIL.



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

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM

MOTION VECTOR 29025.





...CORFIDI

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