

635 

WWUS20 KWNS 201730

SEL0

SPC WW 201730

AZZ000-NMZ000-210000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 770

NWS STORM PREDICTION CENTER NORMAN OK

1130 AM MDT TUE OCT 20 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       PARTS OF SOUTHEAST ARIZONA

       PARTS OF WESTERN NEW MEXICO



EFFECTIVE THIS TUESDAY MORNING AND EVENING FROM 1130 AM UNTIL 600

PM MDT.



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 105

STATUTE MILES EAST AND WEST OF A LINE FROM 40 MILES EAST

SOUTHEAST OF DOUGLAS ARIZONA TO 20 MILES WEST NORTHWEST OF

ALBUQUERQUE NEW MEXICO.  FOR A COMPLETE DEPICTION OF THE WATCH

SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).



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...VIGOROUS UPPER SYSTEM MOVING EWD ACROSS AZ PRECEDED BY

INCREASING MOISTURE/INSTABILITY IN SWLY FLOW.  THUNDERSTORMS WILL

INCREASE IN BOTH NUMBER AND INTENSITY AS THEY DEVELOP EWD ACROSS THE

WATCH THRU THE AFTERNOON.  WITH MLCAPES TO 1000 J/KG...40-50KT OF

SHEAR AND STEEP LAPSE RATES...LARGE HAIL LIKELY WITH STRONGEST

STORMS ALONG WITH LOCALLY DAMAGING WINDS.  THERE IS THE POTENTIAL

FOR ISOLATED SUPERCELLS WHICH WOULD LOCALLY ENHANCE LARGE HAIL AND

WIND THREAT.



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 450. MEAN STORM

MOTION VECTOR 24030.





...HALES

