000
FXUS65 KPSR 120319
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
820 PM MST FRI MAR 11 2011
.SYNOPSIS...
THE STORM TRACK WILL REMAIN WELL NORTH OF ARIZONA THROUGH THE WEEKEND
AND MOST OF NEXT WEEK. MOSTLY CLEAR NIGHTS AND SUNNY WARM DAYS ARE
EXPECTED WITH JUST SOME HIGH CLOUDS AT TIMES. WELL ABOVE AVERAGE
TEMPERATURES FOR MID MARCH ARE EXPECTED TO CONTINUE WITH DESERT HIGHS
INCLUDING PHOENIX...YUMA...EL CENTRO AND IMPERIAL IN THE MID 80S
THIS WEEKEND. HIGHER PRESSURE ALOFT BUILDING IN FROM THE SOUTHWEST IS
EXPECTED TO CAUSE TEMPERATURES TO RISE TO NEAR 90 DEGREES IN MOST
DESERT AREAS BY WEDNESDAY. THE FIRST 90 DEGREE WEATHER OF THE YEAR IS
POSSIBLE IN PHOENIX...YUMA AND EL CENTRO WEDNESDAY.
&&
.DISCUSSION...
FLAT UPPER LEVEL HIGH PRESSURE RIDGE IS IN PLACE OVER THE DESERT
SOUTHWEST THIS EVENING. PLOTS INDICATED LITTLE CHANGE IN 500MB
HEIGHTS AT 00Z...AND HIGH TEMPS REMAINED WELL ABOVE SEASONAL
NORMALS. PHOENIX REACHED 87 TODAY...COMPARED TO 88 YESTERDAY.
AIRMASS IS VERY DRY AND STABLE WITH PWAT VALUES AOB 0.20 INCHES OVER
THE STATE. SURFACE DEWPOINTS CONTINUE TO BE VARIABLE BUT ON THE LOW
SIDE...RUNNING FROM THE TEENS TO MID 30S OVER THE LOWER DESERTS. IR
IMAGERY AT 8 PM INDICATED VARIABLE AMOUNTS OF MAINLY THIN HIGH
CIRRUS MOVING THRU THE FLAT RIDGE AND ACROSS THE CWA. FOR THE REST
OF TONIGHT MOSTLY CLEAR SKIES...LIGHT WINDS AND MILD TEMPS WILL BE
THE RULE AS HIGH PRESSURE DOMINATES OUR WEATHER PATTERN. NO UPDATES
NEEDED TO THE FORECAST ATTM.
.PREVIOUS DISCUSSION...
UNDER SUNNY SKIES...TEMPERATURES WERE CLOSE TO THE SAME ACROSS
SOUTHEAST CALIFORNIA...SOUTHWEST AND SOUTH-CENTRAL ARIZONA TODAY
COMPARED WITH YESTERDAY...BUT GENERALLY SLIGHTLY HIGHER IN SOUTHEAST
CALIFORNIA INCLUDING EL CENTRO AND IMPERIAL. WIND WAS GENERALLY
LIGHT UPSLOPE.
AN ELONGATED WEST TO EAST HIGH PRESSURE SYSTEM ALOFT IS CENTERED
OVER CENTRAL AND SOUTHERN MEXICO AND THE ADJACENT PACIFIC. THE
INFLUENCE OF THIS HIGH PRESSURE SYSTEM EXTENDS WELL NORTH OVER THE
SOUTHWESTERN UNITED STATES RESULTING IN WELL ABOVE AVERAGE
TEMPERATURES FOR MID MARCH IN OUR AREA.
THE DRY AND WEAK SOUTHERN ENDS OF PACIFIC LOW PRESSURE SYSTEMS ARE
EXPECTED TO RESULT IN A SLIGHT WEAKENING OF THE HIGH PRESSURE SYSTEM
OVER OUR AREA THIS WEEKEND. THIS IS EXPECTED TO RESULT IN JUST A
SLIGHT DROP IN TEMPERATURES THIS WEEKEND. HOWEVER...TEMPERATURES
WILL STILL BE WELL ABOVE AVERAGE FOR MID MARCH.
STRONG HIGH PRESSURE ALOFT WEST OF BAJA CALIFORNIA IS EXPECTED TO
BUILD NORTHEAST OVER OUR AREA WITH TEMPERATURES RISING BY TUESDAY
AND WEDNESDAY. MOST DESERT HIGH TEMPERATURES ARE EXPECTED TO RISE
INTO THE MID TO UPPER 80S BY TUESDAY AND TO NEAR 90 DEGREES BY
WEDNESDAY.
THE FIRST 90 DEGREE WEATHER IS POSSIBLE AT PHOENIX...YUMA AND EL
CENTRO WEDNESDAY.
MOSTLY CLEAR NIGHTS AND SUNNY DAYS ARE EXPECTED TO CONTINUE AT LEAST
THROUGH THURSDAY. JUST SOME HIGH CLOUDS ARE EXPECTED AT TIMES FROM
THE WEAK AND DRY SOUTHERN END OF PACIFIC LOW PRESSURE SYSTEMS.
A PACIFIC LOW PRESSURE SYSTEM IS EXPECTED TO CAUSE TEMPERATURES TO
DROP CLOSER TO NORMAL AT THE END OF NEXT WEEK. HOWEVER...THE TIMING
AND STRENGTH OF THIS SYSTEM AND ITS ASSOCIATED COOLING IS UNCERTAIN
THAT FAR AWAY IN TIME.
&&
.AVIATION...
SOUTH-CENTRAL AND SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA
INCLUDING KPHX...KIWA...KIPL...AND KBLH...
WEATHER PATTERN EXHIBITING LITTLE CHANGE...AS SUCH LITTLE CHANGE IN
SENSIBLE WEATHER EXPECTED AT THE AIRFIELDS FOR THE NEXT 24 HOURS.
PERSISTENCE WILL PLAY THE BIGGEST ROLE. WINDS WILL REMAIN MOSTLY
LIGHT AND FOLLOW NORMAL DIURNAL PATTERNS. VARIABLE AMOUNTS HIGH THIN
CIRRUS WILL OVERSPREAD THE AREA...WITH BKN CIGS AT TIMES TONIGHT.
MOST BASES AOA 25K FEET. KPHX/KIWA WINDS SHOULD TURN TO THE EAST
AFTER 06Z TONIGHT...BECOMING VRBL BY NOON SATURDAY. VFR CONDITIONS
ALL AIRFIELDS NEXT 24 HOURS WITH NO AVIATION CONCERNS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH THURSDAY...
HIGH TEMPERATURES WILL REMAIN SEVERAL DEGREES ABOVE NORMAL WITH
LITTLE DAY TO DAY CHANGE. MINIMUM HUMIDITIES WILL REMAIN LOW...NEAR
10 PERCENT AT MANY LOCATIONS...WITH SOME SLIGHT IMPROVEMENT POSSIBLE
TUESDAY AND WEDNESDAY. OVERNIGHT RECOVERY WILL BE MODERATE...BUT
LESS THAN TYPICAL FOR THE HIGHER TERRAIN OF SOUTH-CENTRAL
ARIZONA...WITH SOME IMPROVEMENT POSSIBLE BY WEDNESDAY. WINDS WILL
BE LIGHT...FAVORING FAMILIAR PATTERNS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT
WEATHER.GOV/PHOENIX
DISCUSSION...CB/ELLIS
AVIATION...CB
FIRE WEATHER...AJ
