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510 

WWUS20 KWNS 150758

SEL6

SPC WW 150758

MNZ000-NDZ000-151500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 646

NWS STORM PREDICTION CENTER NORMAN OK

300 AM CDT FRI JUL 15 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHWEST MINNESOTA

       EASTERN NORTH DAKOTA



EFFECTIVE THIS FRIDAY MORNING FROM 300 AM UNTIL 1000 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 80

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 85 MILES SOUTHWEST

OF GRAND FORKS NORTH DAKOTA TO 20 MILES SOUTH SOUTHEAST OF

BEMIDJI MINNESOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).



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 645...



DISCUSSION...ELEVATED TSTMS ARE INTENSIFYING THIS MORNING ACROSS

PARTS OF ERN ND IN RESPONSE TO STRENGTHENING WAA AT THE TERMINUS OF

A 30-40 KT SSWLY LLJ.  THIS LLJ IS ALSO SERVING TO ENHANCE THE NWD

FLUX OF A VERY MOIST AND POTENTIALLY VERY UNSTABLE AIR MASS /REF.

00Z ABR SOUNDING/ ATOP WARM FRONTAL ZONE.  WHEN COUPLED WITH 40-50

KT OF DEEP WLY SHEAR...SETUP WILL FAVOR EMBEDDED SUPERCELL AND

BOWING STRUCTURES CAPABLE OF LARGE HAIL AND DAMAGING WINDS THROUGH

SUNRISE.



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 550. MEAN STORM

MOTION VECTOR 27030.





...MEAD

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