

034 

WWUS20 KWNS 271019

SEL7

SPC WW 271019

AZZ000-NVZ000-271800-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 507

NWS STORM PREDICTION CENTER NORMAN OK

310 AM MST SAT SEP 27 2014



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  WESTERN AND NORTHERN ARIZONA

  SOUTHEASTERN NEVADA



* EFFECTIVE THIS SATURDAY MORNING FROM 310 AM UNTIL 1100 AM MST.



* PRIMARY THREATS INCLUDE...

  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

  ISOLATED LARGE HAIL EVENTS TO 1 INCH IN DIAMETER POSSIBLE

  A TORNADO OR TWO POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 100

STATUTE MILES EAST AND WEST OF A LINE FROM 35 MILES SOUTH OF

PRESCOTT ARIZONA TO 40 MILES NORTH NORTHEAST OF CALIENTE NEVADA.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU7).



PRECAUTIONARY/PREPAREDNESS ACTIONS...



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.



&&



DISCUSSION...TSTMS EXPECTED TO INCREASE OVER WW AREA THROUGH LATER

THIS MORNING AS LOW-LVL MOISTURE CONTINUES TO STREAM NWD IN ZONE OF

STRENGTHENING LARGE-SCALE ASCENT AHEAD OF SLOWLY-PROGRESSIVE CNTRL

CA UPR VORT. 50+ KT SSWLY DEEP SHEAR AND MOIST LOW-LVL ENVIRONMENT

WILL COMPENSATE FOR MODEST MID-LVL LAPSE RATES TO SUPPORT A RISK FOR

SUPERCELLS/SUSTAINED STORM CLUSTERS/LEWPS WITH A CONDITIONAL THREAT

FOR DMGG WIND...MARGINALLY SVR HAIL..AND POSSIBLY A COUPLE

TORNADOES. THE LATTER RISK SHOULD GREATEST OVER NW AZ...WHERE

UPDRAFTS ARE LIKELY TO BE STRONGEST AND MOST DISCRETE/LONG-LIVED.

SHOULD IT BECOME APPARENT THAT GREATER BUOYANCY WILL DEVELOP THAN IS

NOW EXPECTED...AN UPGRADE TO A TORNADO WW MAY BE REQUIRED IN THAT

AREA. IN ADDITION...PARTS OF SW UTAH MAY REQUIRE A SVR WW LATER THIS

MORNING AS LOW-LVL DESTABILIZATION OCCURS IN WAKE OF MESOSCALE RAIN

SYSTEM NOW CROSSING THE REGION.



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

TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS.

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

VECTOR 20035.





...CORFIDI



498 

WWUS20 KWNS 271019

SEL7

SPC WW 271019

AZZ000-NVZ000-271800-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 507

NWS STORM PREDICTION CENTER NORMAN OK

310 AM MST SAT SEP 27 2014



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  WESTERN AND NORTHERN ARIZONA

  SOUTHEASTERN NEVADA



* EFFECTIVE THIS SATURDAY MORNING FROM 310 AM UNTIL 1100 AM MST.



* PRIMARY THREATS INCLUDE...

  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

  ISOLATED LARGE HAIL EVENTS TO 1 INCH IN DIAMETER POSSIBLE

  A TORNADO OR TWO POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 100

STATUTE MILES EAST AND WEST OF A LINE FROM 35 MILES SOUTH OF

PRESCOTT ARIZONA TO 40 MILES NORTH NORTHEAST OF CALIENTE NEVADA.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU7).



PRECAUTIONARY/PREPAREDNESS ACTIONS...



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.



&&



DISCUSSION...TSTMS EXPECTED TO INCREASE OVER WW AREA THROUGH LATER

THIS MORNING AS LOW-LVL MOISTURE CONTINUES TO STREAM NWD IN ZONE OF

STRENGTHENING LARGE-SCALE ASCENT AHEAD OF SLOWLY-PROGRESSIVE CNTRL

CA UPR VORT. 50+ KT SSWLY DEEP SHEAR AND MOIST LOW-LVL ENVIRONMENT

WILL COMPENSATE FOR MODEST MID-LVL LAPSE RATES TO SUPPORT A RISK FOR

SUPERCELLS/SUSTAINED STORM CLUSTERS/LEWPS WITH A CONDITIONAL THREAT

FOR DMGG WIND...MARGINALLY SVR HAIL..AND POSSIBLY A COUPLE

TORNADOES. THE LATTER RISK SHOULD GREATEST OVER NW AZ...WHERE

UPDRAFTS ARE LIKELY TO BE STRONGEST AND MOST DISCRETE/LONG-LIVED.

SHOULD IT BECOME APPARENT THAT GREATER BUOYANCY WILL DEVELOP THAN IS

NOW EXPECTED...AN UPGRADE TO A TORNADO WW MAY BE REQUIRED IN THAT

AREA. IN ADDITION...PARTS OF SW UTAH MAY REQUIRE A SVR WW LATER THIS

MORNING AS LOW-LVL DESTABILIZATION OCCURS IN WAKE OF MESOSCALE RAIN

SYSTEM NOW CROSSING THE REGION.



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

TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS.

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

VECTOR 20035.





...CORFIDI

