

000 

WWUS20 KWNS 102004

SEL1

SPC WW 102004

MNZ000-NDZ000-110300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 581

NWS STORM PREDICTION CENTER NORMAN OK

305 PM CDT FRI AUG 10 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHWEST MINNESOTA

       NORTHEAST NORTH DAKOTA



EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 305 PM UNTIL

1000 PM 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 60

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

GRAND FORKS NORTH DAKOTA TO 50 MILES NORTH NORTHEAST OF BEMIDJI

MINNESOTA.  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 579...WW 580...



DISCUSSION...ELEVATED THUNDERSTORMS THAT FORMED EARLIER OVER

CENTRAL/NE ND MAY BE EVOLVING INTO MORE SURFACE-BASED CONVECTION AS

THE BOUNDARY LAYER WARMS AND CONVECTIVE INHIBITION DECREASES

GRADUALLY.  THERE HAS BEEN SOME TENDENCY FOR MOISTURE TO MIX OUT

FARTHER SE IN MN...BUT A CORRIDOR OF 65-70 F DEWPOINTS SHOULD BE

MAINTAINED ALONG THE ENE-WSW ORIENTED FRONTAL ZONE ACROSS NE ND/NW

MN.  ISOLATED ISOLATED/BRIEF TORNADO CANNOT BE RULED OUT AS STORMS

INTERACT WITH THE SURFACE BOUNDARY...BUT DAMAGING WINDS AND LARGE

HAIL SHOULD BE THE PRIMARY SEVERE STORM THREATS THROUGH THE

AFTERNOON.



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 26035.





...THOMPSON

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