000 
FXUS65 KPSR 201723
AFDPSR
AZZ020>028-CAZ030>033-202245-

SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1020 AM MST WED MAR 20 2002

.SYNOPSIS...
MUCH WARMER WEATHER WITH CLEAR NIGHTS AND SUNNY DAYS ARE FORECAST 
THROUGH FRIDAY...AS STRONG HIGH PRESSURE BUILDS OVER THE REGION. 
UNSEASONABLY WARM TEMPERATURES ARE EXPECTED BY THURSDAY...WHEN 
DAYTIME HIGHS WILL BE NEAR 90 DEGREES OVER MANY LOWER DESERT 
LOCATIONS. HIGH PRESSURE IS FORECAST TO BREAK DOWN THIS WEEKEND AS A 
SERIES OF PACIFIC WEATHER SYSTEMS MOVE INTO THE WESTERN 
STATES...INCLUDING ARIZONA. DRY...COOLER AND BREEZY WEATHER IS 
EXPECTED THIS WEEKEND WITH BELOW NORMAL TEMPERATURES SUNDAY AND 
MONDAY. 

.DISCUSSION...
WARMING TREND OCCURRING AS ADVERTISED. CLEAR SKIES ATTM...AND 
THAT WONT CHANGE AS UPPER RIDGE BUILDS OVER FAR SOUTHEAST 
CALIFORNIA AND SOUTHWEST AZ. 24 HR 500 MB HEIGHTS UP 110 M AT YUMA 
AND 210 M AT TUCSON...WITH 12 HR 500 MB CHANGE +50-60 M. NCEP 500 MB 
ENSEMBLE MEAN FORECAST FOR 00Z THURSDAY INDICATES 500 MB HEIGHTS TO 
RISE 40-50 M TODAY TO NEAR 5800 M...ABOUT 100 M ABOVE CLIMO. NOT 
SURPRISINGLY...YUMA SOUNDING WAS WARMER BY 3-6 C IN 850-950 MB LAYER 
COMPARED TO YESTERDAY. 850 MB TEMPS EXPECTED TO RISE TO ABOVE 16 C 
BY THIS EVENING OVER SOUTH CENTRAL AZ...WITH SOMEWHAT LESSER WARMING 
EXPECTED OVER FAR SOUTHEAST CALIFORNIA AND FAR SOUTHWEST AZ. AS OF 
10 AM MST...24 HR DELTA TEMP OVER SOUTH CENTRAL AZ WAS UP BY 7-9 F 
...WHILE DEW POINTS WERE DOWN 5-10 F. TEMP/DEW POINT TRENDS 
SUPPORTED TO SOME DEGREE BY A SLIGHT DOWNSLOPING 10-20 MPH EAST- 
SOUTHEAST WIND IN 3-8 KFT LAYER. MOST DESERT LOCATIONS TOPPED OUT IN 
THE MID 70S YESTERDAY...AND WITH A 10 DEGREE WARMUP POSSIBLE TODAY 
DAYTIME HIGHS WILL BE IN THE MID 80S AT MOST DESERT LOCATIONS...AND 
HIGHS MAY BE A DEGREE OR TWO WARMER THAN CURRENT FORECAST INDICATES. 
EVEN WARMER TEMPS EXPECTED THURSDAY...WITH HIGHS NEAR OR SLIGHTLY 
ABOVE 90 EXPECTED AT MANY LOWER ELEVATION DESERT LOCALES. CERTAINLY 
THIS WILL BE UNSEASONABLE WARMTH FOR MUCH OF THE FORECAST AREA...AS 
THE AVERAGE HIGH FOR THURSDAY AT PHOENIX IS 77 F. COULD GET CLOSE TO 
RECORD HIGHS OVER SOUTH-CENTRAL AZ THURSDAY...AS THURSDAY RECORD 
HIGH TEMP IS 92 AT PHOENIX. NO UPDATE PLANNED...BUT MAY DECIDE TO 
NUDGE MAX TEMPS UP A BIT MAINLY OVER S-CNTRL AZ FOR TODAY IF CURRENT 
TRENDS CONTINUE.  DG      

.PSR...NONE.