Severe Thunderstorm Warning 56, NWS Phoenix, AZ

AZZ020>028-CAZ030>033-260545-

SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION
WEATHER SERVICE PHOENIX AZ
330 PM MST MON AUG 25 2003

.SYNOPSIS...
A FLOW ALOFT FROM THE EAST THEN SOUTH IS EXPECTED THROUGH WEDNESDAY
AS HIGH PRESSURE ALOFT REMAINS CENTERED NORTH AND EAST OF ARIZONA.
IN ADDITION...THERE WILL BE AN INCREASE IN MOISTURE THROUGH
WEDNESDAY FROM THE EAST SIDE OF HURRICANE IGNACIO WHICH WAS IN THE
SOUTHERN GULF OF CALIFORNIA THIS AFTERNOON. THIS MEANS AN INCREASING
CHANCE OF SHOWERS AND THUNDERSTORMS AND COOLER WEATHER. SOME HEAVY
RAIN IS ALSO POSSIBLE. HIGH PRESSURE ALOFT FROM THE PACIFIC IS
EXPECTED TO BRING A REDUCTION IN THUNDERSTORMS BY FRIDAY.

.DISCUSSION...
TEMPERATURES WERE GENERALLY AT LEAST A FEW DEGREES WARMER AT MID
AFTERNOON TODAY COMPARED WITH THE SAME TIME YESTERDAY. TO GO ALONG
WITH THIS DEW POINT TEMPERATURES WERE A FEW DEGREES HIGHER WITH LOTS
OF MOISTURE IN SOUTHEAST CALIFORNIA. THUS...ISSUED A FLASH FLOOD
WATCH FOR SOUTHEAST CALIFORNIA INCLUDING JOSHUA TREE NATIONAL PARK
UNTIL MIDNIGHT TONIGHT WITH EXCESSIVE RAIN AND FLASH FLOODING
POSSIBLE. THUNDERSTORMS WERE DEVELOPING JUST NEAR THE NORTHEASTERN
MARICOPA COUNTY BORDERS OVER YAVAPAI AND SOUTHERN GILA COUNTIES AND
TO THE SOUTHEAST OVER SOUTHEAST PINAL COUNTY AND SOUTH OVER
COCHISE...SANTA CRUZ AND EVEN PIMA COUNTY IN SOUTHEAST ARIZONA. THE
THUNDERSTORMS ARE ARE EXPECTED TO CONTINUE DEVELOPING WEST AND INTO
THE DESERT AREAS INCLUDING THE GREATER PHOENIX AREA TONIGHT WITH
STRONG GUSTY POSSIBLY DAMAGING WINDS AND LOCALLY HEAVY RAIN.
HURRICANE IGNACIO OVER THE SOUTHERN GULF OF CALIFORNIA WAS OVER THE
SOUTHERN GULF OF CALIFORNIA THIS AFTERNOON AND DRIFTING SLOWLY
TOWARD THE WEST OR NORTHWEST TOWARD BAJA CALIFORNIA. WITH MOISTURE
ALREADY COMING IN FROM THE EAST...THEN MOISTURE FROM THE SOUTHEAST
ON THE EAST SIDE OF IGNACIO...EXPECT AN INCREASING CHANCE OF SHOWERS
AND THUNDERSTORMS ALONG WITH COOLER WEATHER THROUGH WEDNESDAY. THE
MAIN MOISTURE INCREASE IS EXPECTED TUESDAY THROUGH WEDNESDAY LEADING
TO AN INCREASING PROBABILITY OF SHOWERS AND THUNDERSTORMS WITH SOME
HEAVY RAIN AND AN INCREASED FLASH FLOOD POTENTIAL. HIGH PRESSURE
ALOFT FROM THE PACIFIC IS EXPECTED TO BRING A REDUCTION IN
THUNDERSTORMS BY FRIDAY. THEN...A PACIFIC LOW PRESSURE SYSTEM MAY
BRING SOME INCREASE IN THE CHANCE AND SHOWERS AND THUNDERSTORMS THIS
COMING LABOR DAY WEEKEND...MORESO TO OUR NORTH...THEN DRYING EARLY
NEXT WEEK.

.PSR...FLASH FLOOD WATCH FOR SOUTHEAST CALIFORNIA ZONES 30...31...
       32...AND 33...EASTERN RIVERSIDE COUNTY AND IMPERIAL COUNTY
       INCLUDING ALL OF JOSHUA TREE NATIONAL PARK UNTIL MIDNIGHT PDT
       OR 26/0700 GMT.

ELLIS

AZZ020>028-CAZ030>033-260100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PHOENIX AZ
600 AM MST MON AUG 25 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 REMAINS VERY MOIST
AND RATHER UNSTABLE. THUS ISOLATED TO SCATTERED THUNDERSTORMS ARE
FORECAST TODAY...MAINLY IN THE LATE AFTERNOON AND EVENING AND MOST
NUMEROUS OVER SOUTH-CENTRAL ARIZONA. WHERE STORMS FORM...LOCALLY
HEAVY RAINFALL COULD OCCUR WHICH MIGHT LEAD TO FLOODING OF WASHES...
ROADWAY DIPS AND OTHER LOW SPOTS. GUSTY DAMAGING WINDS ARE ALSO
POSSIBLE WITH ANY STORMS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THERE WILL BE AN INCREASED POTENTIAL FOR SHOWERS AND THUNDERSTORMS
WITH HEAVY RAIN TUESDAY INTO WEDNESDAY AS MOISTURE FROM HURRICANE
IGNACIO MOVES NORTH AND INTO SOUTHEAST CALIFORNIA...SOUTHWEST AND
SOUTH-CENTRAL ARIZONA. STAY AWAY FROM FLOODED AREAS INCLUDING
ROADWAYS AND WASHES...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