Severe Thunderstorm Warning 10, NWS Phoenix, AZ

AZZ020>028-CAZ030>033-162245-

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
955 AM MST FRI JUL 16 2004

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

.SYNOPSIS...
HIGH PRESSURE ALOFT TO THE EAST OF ARIZONA WILL CONTINUE A SOUTHEAST
WIND FLOW ACROSS SOUTHERN ARIZONA AND SOUTHEAST CALIFORNIA
TODAY...WHICH WILL KEEP A SLIGHT CHANCE OF MAINLY AFTERNOON AND
EVENING THUNDERSTORMS IN THE FORECAST. BY THE WEEKEND...THE FLOW
WILL BECOME MORE SOUTHERLY AS THE UPPER HIGH SHIFTS A BIT WESTWARD.
THIS WILL MAINTAIN A CONTINUED SLIGHT CHANCE OF AFTERNOON AND
EVENING THUNDERSTORMS OVER SOUTH-CENTRAL ARIZONA...WITH A BIT OF
DRYING IN STORE FOR SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA. IN
THE MEANTIME...TEMPERATURES WILL SHOW A GRADUAL INCREASE OVER THE
NEXT SEVERAL DAYS...AND REMAIN ABOVE NORMAL FOR MUCH OF NEXT WEEK.

&&

.DISCUSSION...
THERE ARE A FEW THINGS I SEE THIS MORNING THAT I LIKE: (1)USING THE
12Z PSR RAOB AND MIXING OUT A LAYER FROM THE SURFACE TO NEARLY 700
MB WITH A MIXING RATIO OF 10.5 G/KG...AND USING A CONVECTIVE TEMP OF
AROUND 104 (WHICH WE WILL EASILY REACH TODAY)...THE CAPE ENDS UP
AROUND 1200 J/KG FOR THIS AFTERNOON (00Z TIME FRAME) (2) THE AMS IS
STILL QUITE MOIST OVER THE VALLEY WITH A PWATER OF 1.74 INCHES (DOWN
FROM YESTERDAYS 12 Z RAOB BUT STILL HIGH) (3) THE 12Z SOUNDING ALSO
SHOWS SOME COOLING AT AROUND 700 MB COMPARED TO THE 00Z PSR SOUNDING
LAST NIGHT. I THINK THE LAYER OF CIN ON LAST NIGHTS PSR SOUNDING
TELLS A LOT...FLAT CU WITH NO FURTHER DEVELOPMENT (WHICH IS WHAT WE
SAW OVER THE DESERTS YESTERDAY) (4) THERE ARE TWO WEAK AREAS OF
CONVECTION OVER MEXICO THIS MORNING WITH AN INVERTED TROF CENTERED
OVER THE CENTRAL PART OF THE GULF OF CALIFORNIA. IF WE CAN GET
FURTHER DEVELOPMENT OVER THIS AREA...HOPEFULLY THE SOUTHEAST
STEERING FLOW WILL BRING SOME OF THIS MOISTURE UP INTO ARIZONA THIS
EVENING. (5) AND FINALLY...THE HIGH CENTER IS ON THE MOVE. THE
HIGH IS SLOWLY SHIFTING FROM THE FOUR CORNERS REGION (MAINLY CO
AREA) SOUTHWARD TOWARD A LOCATION OVER SRN NM BY LATE IN THE
WEEKEND. OFTEN TIMES WHEN THE HIGH IS IN TRANSITION LIKE THIS...WE
END UP WITH SOME SORT OF WIGGLE MOVING THROUGH THE STATE WHICH HELPS
FIRE STORMS OVER THE VALLEY. SO...GENERALLY SPEAKING...I THINK TODAY
WILL BE AN INTERESTING DAY. FURTHER OBSERVATION THIS MORNING OF SAT
TRENDS AND RADAR TRENDS WILL TELL A LOT. WILL BE INTERESTED TO SEE
WHAT SPC HAS TO STAY FOR OUR AREA AS WELL. FOR NOW...WILL HOLD ONTO
THE SLIGHT POPS OVER THE DESERTS...WITH A CHANCE OVER THE HIGHER
TERRAIN. ANY STORMS THAT DO DEVELOP THIS AFTERNOON WILL HAVE A
THREAT OF LOCALLY GUSTY WINDS...AND AREAS WITH LOCALLY HEAVY
RAINFALL.

BEYOND TODAY...AS MENTIONED...THE HIGH IS TRANSITION SOUTH AND
WESTWARD OVER THE NEXT FEW DAYS. THIS SHOULD RESULT IN A MORE
SOUTHERLY...PERHAPS SOUTHWESTERLY...FLOW INTO MUCH OF ARIZONA. THIS
FLOW WILL ALSO CUT US OFF FROM AN EASTERLY WAVES DEVELOPING OVER MEX
AND TX. THE SOUTHWESTERLY FLOW SHOULD ALSO BRING SOME DRIER AIR INTO
THE DESERTS. TEMPS WILL BE INCREASING THIS WEEKEND AND INTO NEXT
WEEK AS WELL. THE CURRENT FORECAST OF A LOW GRADE MONSOON FOR
LATE IN THE WEEKEND INTO EARLY NEXT WEEK LOOKS GOOD. WILL LIKELY
KEEP A CHANCE OVER THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA (AZ
ZONE 24 SOUTHERN GILA COUNTY)...WITH VERY LOW (5 TO 10) POPS IN THE
DESERTS.

&&

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

&&

22

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PHOENIX AZ
1038 AM MST FRI JUL 16 2004

AZZ022>024-027-028-170700-
GREATER PHOENIX AREA-NORTHWEST AND NORTH CENTRAL PINAL COUNTY-
NORTHWEST MARICOPA COUNTY-SOUTHERN GILA/TONTO NF FOOTHILLS-
SOUTHWEST MARICOPA COUNTY-
1038 AM MST FRI JUL 16 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH-CENTRAL ARIZONA.

.DAY ONE...TODAY

THERE IS A RISK OF THUNDERSTORMS TODAY...MAINLY DURING THE AFTERNOON
AND EVENING HOURS. THE MAIN WEATHER HAZARDS WILL BE
LIGHTNING...STRONG GUSTY WINDS...AND LOCALLY HEAVY RAINFALL.
STAY TUNED TO NOAA WEATHER RADIO OR YOUR LOCAL MEDIA OUTLETS FOR
POSSIBLE UPDATES.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THERE IS A RISK OF THUNDERSTORMS...MAINLY OVER THE HIGHER TERRAIN OF
SOUTH-CENTRAL ARIZONA. THE MAIN WEATHER HAZARDS WILL BE
LIGHTNING...STRONG GUSTY WINDS...AND LOCALLY HEAVY RAINFALL.

.SPOTTER CALL TO ACTION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED TODAY FROM 3PM UNTIL MIDNIGHT.

AZZ020-021-025-026-CAZ030>033-170700-
IMPERIAL COUNTY-JOSHUA TREE NATIONAL PARK-
LOWER COLORADO RIVER VALLEY AZ-LOWER COLORADO RIVER VALLEY CA-
RIVERSIDE COUNTY/EASTERN DESERTS-SOUTHWEST DESERTS-
WEST CENTRAL DESERTS-YUMA/MARTINEZ LAKE AND VICINITY-
1038 AM MST FRI JUL 16 2004

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

.DAY ONE...TODAY

THERE IS A SLIGHT RISK OF AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS. THE MAIN THREATS WILL BE REDUCED VISIBILITY IN BLOWING
DUST...LIGHTNING...AND STRONG GUSTY WINDS. STAY TUNED TO NOAA WEATHER
RADIO OR YOUR LOCAL MEDIA FOR POSSIBLE UPDATES.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER CALL TO ACTION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED THIS AFTERNOON AND EVENING.