Severe Thunderstorm Warning 25, NWS Phoenix, AZ

AZZ020>028-CAZ030>033-150545-

SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
327 PM MST SUN JUL 14 2002

.SYNOPSIS...
HIGH PRESSURE ALOFT WILL CONTINUE AS THE MAIN WEATHER FEATURE OVER
SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA THE NEXT SEVERAL DAYS...
BUT IT IS EXPECTED TO WEAKEN A BIT DAY-TO-DAY. MARGINAL LEVELS OF
MONSOON MOISTURE WILL BE AFFECTING THE REGION...PROVIDING A THREAT
OF AFTERNOON THUNDERSTORMS OVER THE CENTRAL ARIZONA MOUNTAINS...WITH
STORMS DRIFTING INTO THE SOUTH-CENTRAL ARIZONA DESERTS DURING THE
EVENING. SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA HAVE A LESSER
CHANCE OF THUNDERSTORMS THAN SOUTH-CENTRAL ARIZONA THE NEXT SEVERAL
DAYS.

.DISCUSSION...
STEERING FLOW REMAINS SOMEWHAT OFF THE HIGH COUNTRY INTO THE S-CNTRL
AZ DESERTS FOR TONIGHT...WITH SOME STORMS EXPECTED TO DRIFT OVER THE
LOWER DESERTS OVERNIGHT. MOST ACTIVE AREA...WITH DYNAMICS AT PLAY...
WILL BE IN THE SERN PART OF THE STATE WHERE A VORT MAX IS AFFECTING
THE AREA. SEVERE TSTM WATCH BOX HAS BEEN ISSUED FOR THAT AREA. THE
STORMS FIRED FIRST OVER THE WHITE MOUNTAINS TODAY...WHEREAS
YESTERDAY THEY BEGAN MORE ON THE CENTRAL AND WRN RIM AREA. RUC
SUGGESTS THE FLOW IS VARYING BETWEEN ELY AND SELY AT 500 MB STEERING
LEVEL THIS AFTERNOON. AVN SEEMS TO CONTINUE TO EXAGGERATE THE
IMPULSES ROTATING AROUND THE HIGH...AND SUGGESTS A CLOSED LOW AND A
QPF BULLSEYE OVER SWRN NM THIS EVENING...WHILE THE ETA HAS A MODEST
VORT MAX OVER SE AZ...WHICH APPEARS TO BE MORE IN LINE WITH WHAT IS
HAPPENING. WE  STILL HAVE NOT HAD A GOOD SURGE OF LOWER-LEVEL
MOISTURE INTO THE DESERTS...ALTHOUGH THE SLY WIND WAS DEEPER
OVERNIGHT AT KYUX THAN IT HAS BEEN...ABOUT 4K FT. LACK OF A GOOD
SURGE...PLUS A TENDENCY FOR SOME DRYING UPSTREAM...HAS LED TO LESS
THAN OPTIMAL COVERAGE OVER THE MOUNTAINS. OPTED OUT OF THE WATCH BOX
AREA...BUT IT IS NOT OUT OF THE QUESTION THAT WE COULD HAVE A SEVERE
WIND EVENT SOMEWHAERE IN THE ERN PORTION OF THE CWA. I MENTIONED
THIS TO SPC...BUT DID NOT FEEL IT MERITED BEING IN A WATCH BOX WHICH
WOULD COVER MORE AREA THAN I WANTED. BIG HIGH TO THE N HAS LOST
ABOUT 60 OR 70 METERS OFF ITS PEAK HEIGHT AND IS EXPECTED TO
CONTINUE TO SLOWLY WEAKEN. THIS SHOULD HELP BRING TEMPS DOWN A
BIT...AND WILL DO LESS FOR MONSOON CIRCULATION. ALL THINGS
CONSIDERED...A BROADBRUSH APPROACH TO THE FORECAST STILL SEEMS THE
BEST WAY TO GO. DECIDED NOT TO ISSUE A HAZARDOUS WEATHER OUTLOOK
TODAY...SINCE MY CONFIDENCE IS LACKING IN PINPOINTING AN EVENT OR
LOCATION.  WILT

.PSR...NONE.

AZZ022>024-027-028-150200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PHOENIX AZ
509 PM MST SUN JUL 14 2002

...HAZARDOUS WEATHER POSSIBLE OVER PORTIONS OF SOUTH-CENTRAL
ARIZONA THIS EVENING...

COUNTIES IN THE RISK AREA INCLUDE...MARICOPA...NORTHWEST PINAL...
AND SOUTHERN GILA.

THE PRIMARY HAZARDOUS WEATHER RISKS INCLUDE: THUNDERSTORMS WITH
STRONG AND DAMAGING WINDS OVER 50 MPH. BLOWING DUST ASSOCIATED WITH
THUNDERSTORM OUTFLOW COULD LOWER VISIBILITIES TO LESS THAN ONE-
QUARTER MILE OVER PORTIONS OF THE LOWER SOUTH-CENTRAL ARIZONA
DESERT.

ADDITIONAL THREATS INCLUDE: INTENSE CLOUD TO GROUND LIGHTNING.
LOCALLY HEAVY RAIN AND HAIL ARE ALSO POSSIBLE...ESPECIALLY
OVER THE HIGHER TERRAIN OF SOUTHERN GILA AND NORTH-CENTRAL PINAL
COUNTIES.

STORM MOVEMENT WILL BE TOWARD THE WEST AT 10 TO 15 MPH. THE PHOENIX
METROPOLITAN AREA IS INCLUDED IN THE OUTLOOK...BUT MAINLY AFTER 7
PM.

STORM SPOTTER ACTIVATION MAY BE NECESSARY THIS EVENING.