000 
FXUS65 KPSR 190457
AFDPSR
AZZ020>028-CAZ030>033-191045-

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
955 PM MST MON APR 18 2005

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

.SYNOPSIS...
TYPICAL DRY SPRING WEATHER WITH CLEAR NIGHTS AND SUNNY DAYS WILL 
CONTINUE AT LEAST THROUGH THURSDAY. THE DRY SOUTHERN END OF A LOW 
PRESSURE SYSTEM MOVING SOUTHEAST OVER THE WESTERN UNITED STATES WILL 
BRING BREEZY AND COOLER WEATHER TUESDAY WITH SOME FURTHER COOLING IN 
SOUTH-CENTRAL ARIZONA INCLUDING THE GREATER PHOENIX AREA WEDNESDAY. 
HIGHER PRESSURE ALOFT WILL BRING SOME RECOVERY IN TEMPERATURES 
THURSDAY AND FRIDAY. INCREASING CLOUDINESS FROM THE SOUTHWEST IS 
EXPECTED THIS COMING WEEKEND AHEAD OF A PACIFIC LOW PRESSURE SYSTEM 
THAT WILL BE MOVING NORTH OFF THE CALIFORNIA COAST.

&&

.DISCUSSION...
UPPER LEVEL LOW PRESSURE TROF CONTINUES TO DEVELOP OVER THE WESTERN 
STATES WITH THE UPPER LOW CENTER CURRENTLY OVER NRN NV. MOST OF THE 
500MB HEIGHT FALLS...40-50M...WERE SEEN ACROSS NV AND NRN UT...WITH 
ONLY 20M FALLS SEEN IN FLG...AND NO FALLS AT ALL AT TUS. AZ IS 
SITUATED ON THE SRN EDGE OF THE TROF AND UNDER A DRY SWLY WINDFLOW. 
IR IMAGERY AT 930 PM SHOWED CLEAR SKIES OVER THE GRAND CANYON 
STATE...AND SRN CA. BREEZY TO WINDY CONDITIONS DEVELOPED THIS 
AFTERNOON...WITH THE STRONGEST WINDS LOCATEDV AT AND WEST OF THE 
LOWER CO RIVER. IPL CAME CLOSEST TO WIND ADVISORY CRITERIA AS 
THEY HAD REPORTED WEST WINDS BETWEEN 30 AND 40 MPH FOR MOST OF THE 
EVENING. THE UPPER LOW WILL NOT MOVE MUCH FOR THE REST OF TONIGHT 
AND THE SURFACE/MID LEVEL GRADIENTS WILL REMAIN TIGHT...SO THE WINDS 
OUT WEST SHOULD ONLY GRADUALLY TAPER OFF AS THE AMS SLOWLY DECOUPLES.

TEMPERATURES LOWERED A HANDFUL OF DEGREES TODAY ACROSS THE CWA AS 
THE HEIGHTS FELL AND SOME COOLER AIR MIXED TO THE GROUND...AND 
PHOENIX ONLY REACHED TO 90 DEGREES. ADDITIONAL COOLING IS ON TAP FOR 
THE NEXT COUPLE OF DAYS AS THE LOW SLOWLY EDGES CLOSER TO ARIZONA 
AND HEIGHTS CONTINUE TO SLOWLY FALL. BREEZY TO WINDY WEATHER IS 
ANTICIPATED AGAIN TUESDAY AS GRADIENTS AT THE SURFACE AND MID LEVELS 
REMAIN RATHER TIGHT. WINDS SHOULD BE SIMILAR TO WHAT WE SAW 
TODAY...AND MOST LIKELY WILL REMAIN BELOW ADVISORY LEVELS. NO 
CHANGES NEEDED TO CURRENT FORECAST.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

11

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