Severe Thunderstorm Warning 32, NWS Phoenix, AZ

AZZ020>028-CAZ030>033-080545-

SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
240 PM MST MON AUG 7 2000

.SYNOPSIS...
THE CHANCE FOR MAINLY LATE AFTERNOON AND NIGHTTIME STORMS WILL
CONTINUE OVER SOUTH CENTRAL ARIZONA THIS WEEK AS A MORE TYPICAL
MONSOON FLOW PREVAILS. SOUTHWEST ARIZONA WILL HAVE A SLIGHT
CHANCE FOR STORMS AS WELL. DAYTIME HIGH TEMPERATURES WILL BE NEAR TO
SLIGHTLY ABOVE SEASONAL NORMALS.

.DISCUSSION...
CONVECTION BREAKING OUT NICELY ALONG THE MOGOLLON RIM...AND OVER SOME
OF THE MOUNTAINS IN SERN AZ AS WELL. UPPER HIGH NOW LOCATED NEAR THE
FOUR CORNERS...WITH A MID LEVEL SELY STEERING FLOW AROUND THE HIGH.
THIS SHOULD HELP MOVE THE STORMS INTO THE CNTRL DESERTS. VERY HIGH
AMOUNTS OF MOISTURE NOW IN PLACE OVER SRN AND SWRN AZ...WITH PWAT
VALUES AT AND ABOVE 1.5 INCHES MANY PLACES...AND SURFACE DEWPOINTS
ACRS THE DESERTS ARE IN THE LOW TO UPPER 60S. ONLY PROBLEM WILL BE
THAT THE TEMPS ARE STRUGGLING TO HEAT UP...EVEN THO DECENT SUNSHINE
IS AVAILABLE. DESPITE LITTLE CONVECTION TO COOL THE BOUNDARY LAYER
LAST NIGHT OVER THE CWA...TEMPS HAVE NOT RECOVERED...AND ARE ACTUALLY
A BIT BEHIND YESTERDAYS PACE. PHX RUNNING 1-2 DEGREES COOLER THAN
YESTERDAY...AND HAS YET TO HIT TRIPLE DIGITS. THIS MOSTLY DUE TO THE
DEEP MOISTURE IN PLACE. STILL...EXPECT TO SEE A CHANCE FOR STORMS
TODAY IN THE ERN CWA...AS THE OUTFLOWS FROM THE STRONG RIM AND SERN
AZ STORMS WORK THEIR WAY WWD AND FORCE ADDITIONAL STORMS TO DEVELOP.
PLENTY OF MOISTURE TO WORK WITH TODAY...IF WE CAN JUST GET A LITTLE
LIFT. NO BIG CHANGES IN THE FORECAST FOR THE NEXT 2 DAYS...AS THE
UPPER HIGH REMAINS NEAR THE FOUR CORNERS. ETA TRIES TO BRING A VORT
MAX SLOWLY AROUND THE HIGH AND ACROSS THE CWA NEXT 2 DAYS...BUT THIS
MAY BE OVERDONE AS NEITHER THE AVN OR NGM IS AS AGRESSIVE WITH THIS
FEATURE. STILL THERE IS POTENTIAL FOR IMPULSES TO COME OUT OF NM...AS
THERE IS STILL A LOW PRESSURE AREA SPINNING THERE...AND MOVE AROUND
THE HIGH HELPING TO CAUSE SHOWERS OR STORMS AT THE NON FAVORABLE
TIMES...SUCH AS MORNING OR EARLY AFTERNOON. THUS WILL USE WORDING
SUCH AS MAINLY EVENING OR MAINLY AFTERNOON STORMS...AND UP POPS JUST
A BIT DURING THE DAYTIME PERIODS. NO BIG CHANGES FOR THE
EXTENDED...AS THE PROGS KEEP A HIGH IN THE VICINITY OF THE FOUR
CORNERS AND KEEP A RATHER STANDARD MONSOONAL FLOW IN PLACE OVER THE
STATE. THIS ELY TO SELY FLOW WILL KEEP MOISTURE AROUND AND THERE
COULD BE CONTINUED RIPPLES THAT MOVE AROUND THE HIGH AND HELP TO SPUR
THE FORMATION OF STORMS. THUS...THE CHANCE FOR MAINLY AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS SOUTHCENTRAL..WITH A SLIGHT CHANCE
SOUTHWEST...WILL HOLD FOR THE THU-SAT PERIOD. WILL OPT TO KEEP THE
WEATHER OUT OF SERN CA THO...AS THE TROF OFF THE CA COAST SHOULD KEEP
A DRY ENOUGH SLY TO SWLY FLOW ALOFT GOING IN THAT AREA AND KEEP
WEATHER THREAT BASICALLY AT OR EAST OF THE LOWER CO RIVERw. 11

AZZ021>024-026>028-080130-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PHOENIX AZ
1040 AM MST MON AUG 7 2000

...SLIGHT RISK FOR SEVERE THUNDERSTORMS OVER SOUTH-CENTRAL
AND SOUTHWEST ARIZONA TONIGHT...

THE SLIGHT RISK AREA ENCOMPASSES MARICOPA...SOUTHERN GILA ...
NORTHWEST PINAL...YUMA AND LA PAZ COUNTIES. IT INCLUDES THE GREATER
PHOENIX METROPOLITAN AREA AS WELL AS THE CITIES OF GLOBE...COOLIDGE
...CASA GRANDE...GILA BEND...WICKENBURG...BOUSE...TACNA...QUARTZSITE
AND WENDON.

THE PRIMARY WEATHER THREATS FROM THE THUNDERSTORMS TONIGHT WILL BE
LOCALLY HEAVY RAINFALL WHICH MAY CAUSE FLOODING OF WASHES...STREETS
AND LOW LYING AREAS...STRONG GUSTY AND POSSIBLY DAMAGING WINDS...
AND BLOWING DUST THAT COULD LOWER VISIBILITIES TO BELOW ONE QUARTER
MILE. DEADLY CLOUD-TO-GROUND LIGHTNING IS LIKELY WITH THESE STORMS.
IN ADDITION...LARGE HAIL IS POSSIBLE...BUT LESS OF A THREAT.

SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER THE HIGHER
TERRAIN OF CENTRAL AND SOUTHEAST ARIZONA LATER THIS AFTERNOON...THEN
GRADUALLY WORK THEIR WAY SOUTH AND WEST INTO SOUTH-CENTRAL AND
SOUTHWEST ARIZONA. STORMS COULD PERSIST PAST MIDNIGHT...BUT THE
CHANCES FOR SEVERE WEATHER WITH THEM WILL BE REDUCED.

STORM SPOTTER ACTIVATION MAY BE NECESSARY LATER TODAY.

CJB