Severe Thunderstorm Warning 12, NWS Phoenix, AZ

AZZ020>028-CAZ030>033-240545-

SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
305 PM MST FRI JUN 23 2000

.SYNOPSIS...
MONSOON MOISTURE WILL REMAIN OVER THE AREA INTO EARLY NEXT WEEK.
UPPER AIR DISTURBANCES WILL INTERACT WITH THE MOISTURE TO BRING A
CHANCE FOR THUNDERSTORMS MAINLY TO SOUTH CENTRAL ARIZONA. AN INCREASE
IN MOISTURE AND THUNDERSTORM ACTIVITY IS POSSIBLE SUNDAY AND MONDAY
AS THE REMAINS OF CARLOTTA APPROACH THE CENTRAL BAJA CALIFORNIA
COAST. DAYTIME HIGH TEMPERATURES WILL BE CLOSE TO AVERAGE.

.DISCUSSION...
ISSUED HAZARDOUS WEATHER OUTLOOK TO ADDRESS CONVECTION EXPECTED OVER
SOUTH CENTRAL ARIZONA THIS AFTERNOON AND EVENING. NO OBVIOUS UPPER
JET STREAKS OR OTHER TRIGGERS SATURDAY...SO HAVE DOWNPLAYED CHANCE
FOR STORMS OVER DESERT BUT KEPT CHANCE OVER SOUTH CENTRAL HIGHER
TERRAIN. YUMA VWP ALREADY DEPICTING SOUTH-SOUTHEAST FLOW TO 6K
FT...WITH DEW POINTS THERE ONLY IN THE UPPER 50S. GULF SURGE A
DISTINCT POSSIBILITY SATURDAY AS CARLOTTA PASSES JUST SOUTH AND WEST
OF SOUTHERN BAJA CALIFORNIA. MOISTURE INCREASE LIKELY BY LATE
SATURDAY INTO SUNDAY ACROSS MUCH OF CWA...AND WITH DISTURBANCES
FORECAST TO AFFECT THE AREA IN SOUTHWEST FLOW...HAVE GONE WITH CHANCE
WORDING SUNDAY AND MONDAY. EXCESSIVE RAINFALLS WILL BE A POSSIBILITY
OVER MAINLY EASTERN HALF OF CWA BY MONDAY. WILL PROBABLY STILL HAVE
DECENT LOW LEVEL MOISTURE OVER SOUTH CENTRAL DESERT TUESDAY AND
WEDNESDAY...SO HAVE LEFT CHANCE WORDING IN EXTENDED FOR ARIZONA ZONES
23/24/28. AVN SEEMED TO HAVE DECENT HANDLE ON HEIGHT/WIND FIELDS
TODAY...BUT I WAS NOT CONFIDENT THAT ANY OF THE AVAILABLE NUMERICAL
MODELS HANDLED MOISTURE WELL. DG

AZZ021>024-027-028-240000-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PHOENIX AZ
247 PM MST FRI JUN 23 2000

...SLIGHT RISK FOR HAZARDOUS WEATHER OVER NORTHERN AND CENTRAL
MARICOPA...NORTHERN PINAL...AND SOUTHERN GILA COUNTIES LATE THIS
AFTERNOON AND THIS EVENING...

CITIES AND TOWNS INCLUDED IN THE SLIGHT RISK AREA INCLUDE THE
GREATER PHOENIX METROPOLITAN AREA...GLOBE...MIAMI...WICKENBURG...
SUPERIOR...FLORENCE...APACHE JUNCTION...COOLIDGE...AND CASA GRANDE.

THE AIRMASS OVER SOUTH CENTRAL ARIZONA IS VERY MOIST AND UNSTABLE.
STRONG TO OCCASIONALLY SEVERE THUNDERSTORMS WILL AFFECT PORTIONS OF
CENTRAL AND SOUTHEAST ARIZONA THIS AFTERNOON...INCLUDING LA PAZ...
YAVAPAI...PIMA...AND SOUTHERN PINAL COUNTIES. OUTFLOW WINDS FROM
THESE STORMS ARE EXPECTED TO MOVE TOWARD THE SLIGHT RISK AREA LATER
THIS AFTERNOON AND TRIGGER SCATTERED THUNDERSTORM DEVELOPMENT THIS
EVENING AND EARLY TONIGHT.

STORMS OVER THE SOUTH CENTRAL DESERT WILL BE CAPABLE OF PRODUCING
STRONG WINDS AND DENSE BLOWING DUST. LOCALLY HEAVY RAINFALL IS ALSO
POSSIBLE...BUT STORM MOVEMENT TOWARD THE NORTHEAST AT 15 MPH WILL
DECREASE THE CHANCE FOR EXCESSIVE RAINFALL. HOWEVER...STORMS
OVER THE HIGHER TERRAIN OF NORTH-CENTRAL AND NORTHEAST MARICOPA
COUNTY...AS WELL AS SOUTHERN GILA COUNTY...COULD PRODUCE ENOUGH RAIN
TO RESULT IN RUNNING WASHES. ALL STORMS WILL PRODUCE DANGEROUS CLOUD
TO GROUND LIGHTNING.

THE HAZARDOUS WEATHER OUTLOOK GIVES PRELIMINARY INFORMATION FOR THE
POSSIBILITY OF WEATHER THAT COULD BECOME SEVERE...DAMAGING WINDS IN
EXCESS OF 57 MPH...DENSE BLOWING DUST THAT RESTRICTS VISIBILITY
TO 1/4 MILE OR LESS...HAIL 3/4 INCH IN DIAMETER OR LARGER...AND
HEAVY RAINFALL THAT COULD CAUSE FLOODING OR RUNNING WASHES. WHEN
SEVERE WEATHER OR FLOODING BEGINS...IMPORTANT LIFE SAVING
INFORMATION WILL BE PROVIDED IN SHORT TERM FORECASTS...SEVERE
WEATHER AND FLOOD WARNINGS...AND IN FOLLOW-UP STATEMENTS.

STORM SPOTTER ACTIVATION MAY BE NECESSARY LATE THIS AFTERNOON
OR EARLY THIS EVENING.

DG