Severe Thunderstorm Warning 23, NWS Phoenix, AZ

AZZ020>028-CAZ030>033-260545-

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
325 PM SUN JUL 25 2004

SOUTHWEST AND SOUTH-CENTRAL ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION

.SYNOPSIS...
MOISTURE WILL CONTINUE AROUND THE DESERT SOUTHWEST FOR A COUPLE MORE
DAYS GIVING A THREAT FOR ADDITIONAL AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS. HOWEVER...THE FLOW ALOFT WILL TURN MORE WEST OR
NORTHWEST BY MIDWEEK...WHICH WILL RESULT IN A DRYING TREND AND A
TEMPORARY LULL IN THE MONSOON. BY THE WEEKEND...THE UPPER HIGH WILL
DEVELOP OVER THE SOUTHERN GREAT PLAINS...HELPING TO BRING A RETURN
OF MOISTURE AND THE THREAT OF AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS ACROSS SOUTH-CENTRAL ARIZONA. DAYTIME TEMPERATURES
WILL REMAIN SEASONABLY WARM DURING THIS NEW WEEK.

&&

.DISCUSSION...
HAVE NOT GIVEN UP HOPE THAT WE MAY STILL BE IN FOR AN ACTIVE EVENING
AROUND THE CWA...AS FACTORS MENTIONED IN THE MORNING DISCUSSSION
STILL IN PLAY. HOWEVER...ONE LARGE NEGATIVE FACTOR FOR WIDESPREAD
DESERT STORMS THIS EVENING IS THAT THE AFTERNOON DEWPOINTS HAVE
DROPPED INTO THE MID 50S. ADD TO THIS THAT THERE ARE REALLY NO UPPER
IMPULSES TO ACT AS TRIGGERS...WE WILL HAVE TO TOTALLY RELY ON
COLLIDING OUTFLOW BOUNDARIES TO GET DESERT REDEVELOPMENT THIS
EVENING...AND THESE BOUNDARIES MAY BE FEW AND TOO FAR BETWEEN.
CONVECTION THAT HAS FORMED ALONG THE RIM AND TO OUR SE HAVE THUS FAR
WEAKENED AS THEY HAVE PROPOGATED TOWARDS THE DRIER ENVIRONS OF THE
LOWER DESERTS. HOWEVER...IT IS STILL RELATIVELY EARLY TO GET TOO
PESSIMISTIC ABOUT THE THUNDERSTORM POTENTIAL THIS EVENING. DECIDED
TO LEAVE POPS AT THE 40 PERCENT THAT WAS INHERITED FROM MIDNIGHT
SHIFT FOR THE SCNTRL DESERTS...DROPPING TO 10S AND 20S IN THE FAR
WRN CWA. FOR TOMORROW...STEERING FLOW REMAINS OUT OF THE NE...SO IF
WE GET LITTLE ACTIVITY TONIGHT TO STABLIZE THE AMS...MONDAY EVENING
COULD BE QUITE ACTIVE. PROGS ARE STILL POINTING TOWARDS A STRONG
DRYING TREND BY MIDWEEK...WHICH SHOULD LAST 3 OR 4 DAYS. THIS BEING
CAUSED BY ANOMALOUSLY STRONG WLYS ONCE AGAIN DROPPING DOWN TO OUR
LATITUDE. BY THE WEEKEND...UPPER HIGH REBUILDS TO OUR E...WHICH
SHOULD ALLOW A MORE MOIST SELY FLOW TO RETURN TO THE ERN CWA. WILL
CONTINUE THE SLIGHT UPSWING IN ACTIVITY BY SATURDAY AND SUNDAY FOR
BASICALLY MARICOPA COUNTY EWD. AFTERNOON TEMPS SHOULD NOT VARY TOO
MUCH DAY-TO-DAY...WITH THE EXCEPTION OF EITHER TOMORROW OR TUESDAY
WHEN ANY CONVECTIVE DEBRIS WOULD CUT DOWN ON INSOLATION. NIGHTTIME
LOWS WILL PROBABLY TAKE A SLIGHT DIP LATER THIS WEEK WITH LOWER
DEWPOINTS.

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.

&&

ESTLE

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PHOENIX AZ
1001 AM MST SUN JUL 25 2004

AZZ021>024-026>028-260700-
GREATER PHOENIX AREA-NORTHWEST AND NORTH CENTRAL PINAL COUNTY-
NORTHWEST MARICOPA COUNTY-SOUTHERN GILA/TONTO NF FOOTHILLS-
SOUTHWEST DESERTS-SOUTHWEST MARICOPA COUNTY-WEST CENTRAL DESERTS-
1001 AM MST SUN JUL 25 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH-CENTRAL AND PARTS OF
SOUTHWEST ARIZONA.

.DAY ONE...TODAY

SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON AND
EVENING...WITH DAMAGING WIND THE MAIN THREAT. TREES...POWER
LINES...AND POORLY CONSTRUCTED BUILDINGS WILL BE MOST AT RISK.
THERE WILL ALSO BE A THREAT OF DENSE BLOWING DUST WITH REDUCED
VISIBILITIES IN THE DESERTS UNDER A MILE AT TIMES.

STAY TUNED TO NOAA WEATHER RADIO OR YOUR LOCAL MEDIA OUTLETS FOR
POSSIBLE WATCHES OR WARNINGS.

THUNDERSTORMS WILL ALSO BE ACCOMPANIED BY HEAVY RAINS. THIS MAY CAUSE
MINOR FLOODING OF POOR DRAINAGE AND LOW LYING AREAS...AS WELL AS
URBAN STREET INTERSECTIONS. WASHES MAY ALSO BEGIN FLOWING.

DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

THERE WILL BE A CONTINUED CHANCE OF SHOWERS AND THUNDERSTORMS ONCE
AGAIN MONDAY AFTERNOON AND EVENING...AND AGAIN TUESDAY AFTERNOON AND
EVENING. THE STRONGEST STORMS COULD ALSO PRODUCE STRONG...GUSTY WINDS
AND HEAVY RAIN. SOME SIGNIFICANT DRYING IS EXPECTED
WEDNESDAY...THURSDAY AND FRIDAY WITH NO HAZARDOUS WEATHER EXPECTED.
THERE WILL BE A SLIGHT CHANCE OF THUNDERSTORMS AGAIN ON SATURDAY.

.SPOTTER CALL TO ACTION STATEMENT...

SPOTTER ACTIVATION IS LIKELY THIS EVENING.

AZZ020-025-CAZ031>033-260700-
IMPERIAL COUNTY-LOWER COLORADO RIVER VALLEY AZ-
LOWER COLORADO RIVER VALLEY CA-RIVERSIDE COUNTY/EASTERN DESERTS-
YUMA/MARTINEZ LAKE AND VICINITY-
1001 AM MST SUN JUL 25 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EXTREME SOUTHWEST ARIZONA AND
MOST OF SOUTHEAST CALIFORNIA.

.DAY ONE...TODAY

THERE WILL BE A CHANCE OF AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS ACROSS THE AREA. THE MAIN THREAT THAT THESE STORMS WILL
POSE WILL BE HEAVY RAINS...WHICH MAY CAUSE MINOR FLOODING OF POOR
DRAINAGE AND LOW LYING AREAS. WASHES MAY BEGIN FLOWING.
THERE COULD ALSO BE SOME DENSE BLOWING DUST...WHICH COULD REDUCE
VISIBILITIES AT TIMES TO UNDER A MILE.

DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

THERE WILL BE A SLIGHT CHANCE OF AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS AGAIN ON MONDAY...WITH HEAVY RAIN THE MAIN THREAT. A
DRYING TREND IS BEING FORECAST TUESDAY THROUGH SATURDAY WITH LITTLE
IF ANY THREAT OF HAZARDOUS WEATHER EXPECTED.

.SPOTTER CALL TO ACTION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED THIS AFTERNOON AND EVENING.

CAZ030-260700-
JOSHUA TREE NATIONAL PARK-
1001 AM MST SUN JUL 25 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR JOSHUA TREE NATIONAL PARK.

.DAY ONE...TODAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER CALL TO ACTION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED.