

000 

WWUS20 KWNS 170653

SEL4

SPC WW 170653

MTZ000-171400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 404

NWS STORM PREDICTION CENTER NORMAN OK

1255 AM MDT SUN JUN 17 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL AND EASTERN MONTANA



EFFECTIVE THIS SUNDAY MORNING FROM 1255 AM UNTIL 800 AM MDT.



HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 60

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 40

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 10 MILES NORTHEAST

OF SIDNEY MONTANA TO 25 MILES WEST SOUTHWEST OF HARLOWTON

MONTANA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).



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...THIS SEVERE THUNDERSTORM WATCH REPLACES

TORNADO WATCH NUMBER 401. WATCH NUMBER 401 WILL NOT BE IN EFFECT

AFTER 1255 AM MDT. CONTINUE...WW 403...



DISCUSSION...ELEVATED SUSTAINED STORMS/POSSIBLE SUPERCELLS EXPECTED

TO PERSIST ALONG NW FRINGE OF 700 MB THERMAL AXIS PROGRESSING E

AHEAD OF STRONG PAC NW UPR TROUGH.  WITH AMPLE CLOUD LAYER SHEAR FOR

SUSTAINED ROTATING UPDRAFTS...POTENTIAL WILL EXIST FOR HAIL AND

POSSIBLY HIGH WIND WITH THE WIDELY SCTD STORMS.



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

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 50

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM

MOTION VECTOR 25040.





...CORFIDI

