883 
FXUS65 KPSR 281729
AFDPSR
AZZ020>028-CAZ030>033-282245-

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1030 AM MST WED APR 28 2004

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

.SYNOPSIS...
A STRONG LOW PRESSURE SYSTEM FROM THE NORTH WILL BRING WINDY WEATHER
AND AREAS OF BLOWING SAND AND DUST TODAY THROUGH THURSDAY WITH MUCH 
COOLER WEATHER THURSDAY. THERE MAY BE ENOUGH MOISTURE FOR A SLIGHT 
CHANCE OF SHOWERS AND THUNDERSTORMS EAST OF THE GREATER PHOENIX AREA 
THIS AFTERNOON AND EVENING. OTHERWISE...IT WILL BE MOSTLY SUNNY TODAY
AND MOSTLY CLEAR TONIGHT. STRONG HIGH PRESSURE ALOFT FROM THE PACIFIC
WILL BRING BACK WARMER WEATHER THIS WEEKEND AND EARLY NEXT WEEK WITH 
CONTINUED MOSTLY CLEAR NIGHTS AND SUNNY DAYS.

&&

.DISCUSSION...
INTERESTING WX SCENARIO SHAPING UP WITH STRONG UPPER LOW DROPPING 
SEWD TOWARDS AZ TODAY. FIRST OFF...SYSTEM WILL BE QUITE DRY FOR THE 
PHX CWA PER MODEL RH TRENDS. STILL MAY BE ENOUGH MOISTURE FOR AN 
ISOLATED AFTERNOON TSTM OR TWO FAR E...AS CURRENTLY IN FORECASTS.
WINDS WILL BE THE MAIN EVENT WITH THIS SYSTEM. GRADIENTS EXPECTED TO 
TIGHTEN MARKEDLY AS THE DAY PROGRESSES...FIRST OUT WEST. CURRENT 
WIND ADVISORY LOOKING GOOD FOR OUT THERE. ONE CHANGE WE MAY NEED TO 
MAKE...HOWEVER...IS TO EXTEND THIS ADVISORY RIGHT ON THRU THE NIGHT.
THIS GOES AGAINST CLIMATOLOGY WHICH USUALLY ATTEMPTS TO DE-COUPLE 
WINDS AFTER MIDNIGHT. HOWEVER...AS VORT MAX ROTATES INTO THE CA 
PORTION OF CWA LATE TONIGHT...AND COLD FRONT APPROACHES...EXPECTING 
A SPIKE IN WIND SPEEDS IN CA ZONES SOMETIME BETWEEN 06Z AND 12Z. 
WILL MULL OVER ADVISORY EXTENSION FOR AFTERNOON PACKAGE. WIND 
ADVISORY FOR THURSDAY FOR ERN CWA ALSO LOOKS ON TRACK...THOUGH MAY 
NEED TO EXTEND IT A BIT FURTHER W...LIKE IN ZONES 21 AND 26. SHOULD 
BE LESS WIND BY 18Z THU OUT W. 

NOW FOR THE RED FLAG FIRE WEATHER CONDITIONS. FIRST OFF...WIND 
SPEEDS AND FIRE DANGER RATINGS ARE THE NO-BRAINERS WITH THIS CURRENT 
SITUATION. AM A LITTLE CONCERNED WITH THE FACT THAT OUR 24 HOUR RH 
CHANGES ARE UP 10 TO 20 PERCENT FROM YDA. THIS DUE TO THE FACT MOST 
PLACES ARE BLOWING OUT OF THE SE AHEAD OF TROUGH. AM BANKING ON NEAR 
SURFACE WINDS TO TURN MORE TO THE SW BY THIS AFTERNOON...WHICH WOULD 
LOWER RHS BACK DOWN TO NEAR OR BELOW 15 PCT. SO...WILL LEAVE RED 
FLAG WARNINGS IN EFFECT TODAY...AND WILL BE CONSIDERING THE IDEA OF 
EXTENDING WARNING FOR ERN CWA ON THU. 

TEMP-WISE...STILL LOOKING FOR SOME NICE COOLING ON THURSDAY WITH ANY 
WARMING HOLDING OFF UNTIL SATURDAY.

APPROACHING TROUGH FORECAST TO DROP DOWN TO NEAR FOUR CORNERS REGION 
BY THU EVENING AND THEN ACCELERATE EWD AWAY FROM THE STATE BY LATE 
FRIDAY...WITH STRONG RIDGING AND WARMING FOR THE WEEKEND. 

CURRENT FORECASTS APPEAR TO BE IN GOOD SHAPE FOR NOW...NO UPDATES.
 
&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...WIND ADVISORY FOR SOUTHWEST ARIZONA INCLUDING THE LOWER
     COLORADO RIVER VALLEY NORTH OF YUMA...ZONES 20...21...AND 26
     FROM 12 NOON MST (1900 GMT) TODAY THROUGH 9 PM MST (0400 GMT)
     TONIGHT.
     WIND ADVISORY FOR SOUTH-CENTRAL ARIZONA INCLUDING THE
     GREATER PHOENIX AREA FOR THURSDAY.
     RED FLAG WARNING FOR ALL OF SOUTHWEST AND SOUTH-CENTRAL
     ARIZONA...FIRE WEATHER ZONES 131...132 AND 133...FROM
     12 NOON MST (1900 GMT) THIS AFTERNOON THROUGH 7 PM MST
     (0200 GMT) THIS EVENING.
CA...WIND ADVISORY FOR SOUTHEAST CALIFORNIA INCLUDING THE LOWER
     COLORADO RIVER VALLEY...ZONES 30...31...32...AND 33 FROM
     12 NOON PDT (1900 GMT) TODAY THROUGH 9 PM PDT (0400 GMT)
     TONIGHT.
     RED FLAG WARNING FOR ALL OF SOUTHEAST CALIFORNIA...
     FIRE WEATHER ZONES 230...231 AND 232...FROM 12 NOON PDT
     (1900 GMT) THIS AFTERNOON THROUGH 7 PM PDT (0200 GMT)
     THIS EVENING.

&&

$$

ESTLE