

195 

WWUS20 KWNS 080317

SEL5

SPC WW 080317

IAZ000-MNZ000-081000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 675

NWS STORM PREDICTION CENTER NORMAN OK

1015 PM CDT FRI AUG 7 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL INTO NORTHERN IOWA

       SOUTHERN INTO CENTRAL MINNESOTA



EFFECTIVE THIS FRIDAY NIGHT AND SATURDAY MORNING FROM 1015 PM

UNTIL 500 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 75

STATUTE MILES EAST AND WEST OF A LINE FROM 50 MILES SOUTHEAST OF

FORT DODGE IOWA TO 35 MILES NORTH OF REDWOOD FALLS MINNESOTA.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU5).



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 672...WW 673...WW 674...



DISCUSSION...THUNDERSTORMS WILL INCREASE IN COVERAGE AND INTENSITY

ALONG NOSE OF STRENGTHENING LLJ OVERNIGHT...AS ELEVATED INSTABILITY

REMAINS QUITE STRONG.  THE MAJORITY OF THESE STORMS WILL REMAIN

ELEVATED... ALTHOUGH SUFFICIENT DEEP LAYER SHEAR WILL BE IN PLACE

FOR SUPERCELLS AND INCREASE THE RISK OF LARGE HAIL.  ISOLATED WIND

DAMAGE IS ALSO POSSIBLE WITH THE MORE ORGANIZED STORMS THROUGH MUCH

OF THE NIGHT.  ACTIVITY MAY CONSOLIDATE INTO A LARGER MCS AND SPREAD

TOWARDS THE UPPER MS RIVER VALLEY.



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 25025.





...EVANS

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