Flash Flood Warning 8, NWS Phoenix, AZ

AZZ020>028-CAZ030>033-241745-

SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION
WEATHER SERVICE PHOENIX AZ
310 AM MST SUN AUG 24 2003

.SYNOPSIS...
A FLOW ALOFT FROM THE EAST THEN SOUTH IS EXPECTED AT LEAST THROUGH
THE FIRST HALF OF THE COMING WEEK AS HIGH PRESSURE ALOFT REMAINS
CENTERED NORTH AND EAST OF ARIZONA. THIS MEANS AN INCREASING CHANCE
OF SHOWERS AND THUNDERSTORMS WITH LOCALLY HEAVY RAIN AND GUSTY WINDS
THROUGH TUESDAY AND TUESDAY NIGHT. THE REMAINS OF HURRICANE IGNACIO
ARE EXPECTED TO MOVE NORTH INTO THE SOUTHWESTERN UNITED STATES BY
TUESDAY AND TUESDAY NIGHT WITH AN INCREASING CHANCE OF HEAVY RAIN.

.DISCUSSION...
VERY MOIST MONSOON AIRMASS REMAINS IN PLACE OVER ARIZONA...WITH
SURFACE DEWPOINTS OVER MOST DESERTS IN THE 60S TO LOW 70S. GOES PWAT
IMAGERY SHOWS A PLUME OF 1.5 INCH PLUS VALUES INTO SWRN AZ AND SERN
CA...AND WATER VAPOR IMAGERY SHOWS THE CLASSIC MONSOON MOISTURE
PLUME RUNNING FROM NWRN MEXICO THRU AZ AND TURNING NEWD INTO UT AND
CO. MOISTURE IN THE PLUME BEING FED FROM HURRICANE IGNACIO OFF THE
SRN TIP OF BAJA CA. CONVECTION OVER SERN AZ AND MUCH OF NW/WCNTRL
MEXICO VERY ACTIVE TONIGHT...AIDED BY STRONG UPPER DIFLUENCE AND
STRETCHING SEEN AHEAD OF AN INVERTED TROF OVER TEXAS AND PARTS OF
NWRN MEX. THIS CONVECTION HAS MOVED STEADILY WEST OVERNIGHT...AND
NEW STORMS FIRED AROUND MIDNIGHT IN SERN CA AHEAD OF THE MAIN
COMPLEX WHICH HAD FORMED JUST SOUTH OF THE AZ BORDER. FOR THE REST
OF TONIGHT...WITH OUTFLOW BOUNDARIES MOVING ABOUT AND INTERACTING
THERE WILL BE A CONTINUED SLIGHT CHANCE FOR STORMS OVER MOST OF OUR
CWA...SPCLY THE WESTERN DESERTS INTO SERN CA.

LATEST PROGS BASICALLY KEEP AZ IN THE MONSOON SOUP THRU AT LEAST
TUESDAY...WITH VERY HIGH 850MB DEWPOINTS IN PLACE...AND SURFACE
DEWPOINTS IN THE 60S TO MID 70S. UPPER HIGH REMAINS CENTERED WELL TO
OUR NE...WITH THE AXIS RUNNING SWWD DOWN THRU THE FOUR CORNERS AND
THRU SWRN AZ...AND OFF THE BAJA COAST. FOR THE NEXT COUPLE OF DAYS
THE INVERTED TROF WILL SLOWLY WORK WEST KEEPING DIFLUENCE GOING OVER
SRN AZ...AND AIDING STORM DEVELOPMENT. ACTUALLY...UPPER STREAMLINE
FORECASTS FOR THE NEXT COUPLE OF DAYS SHOW A VERY CHAOTIC AND
DEFORMED PATTERN...HARD TO SAY EXACTLY WHERE THE BEST AREA FOR
ENHANCED UVV WILL END UP. WITH A GOOD SELY TO ELY STEERING FLOW
REMAINING IN PLACE...AND MOISTURE CONTINUING TO BE FED FROM
IGNACIO...SHOULD SEE A MEDIUM TO HIGH GRADE MONSOON THRU EARLY NEXT
WEEK WITH CHANCE POPS OVER OUR ERN ZONES MAINLY IN THE EVE
HOURS...AND 20 PERCENTS POPS ELSEWHERE FOR MOST TIMES OF THE DAY.
COULD SEE STORMS IN THE MORNING...AFTERNOON OR NIGHT MOST PLACES
WITH THE AIRMASS BEING SO MOIST AND UNSTABLE. WITH THE ONGOING
WEATHER TONIGHT HAVE NOT BEEN ABLE TO REALLY ADDRESS THE EXTENDED
PART OF THE FORECAST...SO IT HAS BEEN LEFT ALONE. IT DOES APPEAR
THAT BY THURSDAY...A DRIER SOUTHWEST FLOW WILL START TO AFFECT OUR
WESTERN ZONES...LEADING TO A DECREASING THREAT FOR STORMS IN THOSE
AREAS. TEMPS SHOULD BE LOWERING OVER THE NEXT FEW DAYS...DUE TO
INCREASED CLOUD COVER AND CONVECTION.  11

.PSR...NONE.

AZZ020>028-CAZ030>033-250100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PHOENIX AZ
600 AM MST SUN AUG 24 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHWEST AND
SOUTH-CENTRAL ARIZONA...AND SOUTHEAST CALIFORNIA.

.DAY ONE...TODAY

THE AIRMASS OVER ARIZONA AND SOUTHEAST CALIFORNIA CONTINUES TO BE
VERY MOIST AND UNSTABLE...THUS ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS ARE FORECAST TODAY...MAINLY IN THE AFTERNOON...AND
MOST NUMEROUS OVER SOUTH-CENTRAL ARIZONA LATER THIS AFTERNOON AND
EVENING. WHERE STORMS FORM THERE IS A CHANCE FOR LOCALLY HEAVY
RAINFALL WHICH COULD LEAD TO FLOODING OF WASHES...ROADWAY DIPS AND
OTHER LOW SPOTS. IN ADDITION...GUSTY DAMAGING WINDS ARE POSSIBLE
WITH ANY STORMS.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

THERE WILL BE A CONTINUED POTENTIAL FOR SHOWERS AND THUNDERSTORMS
WITH LOCALLY HEAVY RAIN...AND POSSIBLE FLOODING...MONDAY AND TUESDAY
AS THE REMAINS OF HURRICANE IGNACIO MOVE NORTH INTO THE SOUTHWESTERN
UNITED STATES. THE THREAT WILL INCLUDE SOUTHWEST AND SOUTH-CENTRAL
ARIZONA AS WELL AS SOUTHEAST CALIFORNIA. STAY AWAY FROM FLOODED
AREAS INCLUDING ROADWAYS AND BE PREPARED TO MOVE TO HIGHER GROUND
SHOULD A WARNING BE ISSUED.

.INSTRUCTIONS TO SPOTTERS...
WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

BRECKENRIDGE