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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ 
225 PM MST THU MAY 28 2015

.SYNOPSIS... 
HOT AND DRY WEATHER WILL ARRIVE INTO SOUTHEAST CALIFORNIA AND 
SOUTHERN ARIZONA THIS WEEKEND WITH AFTERNOON HIGHS RANGING FROM 
AROUND 102 TO 108 DEGREES FOR LOWER ELEVATION POPULATION CENTERS. 
TEMPERATURES WILL COOL SOMEWHAT NEXT WEEK...COMING CLOSER TO THE 
SEASONAL NORMAL HOWEVER WITH NO RAINFALL STILL ANYWHERE NEAR THE 
AREA. 
 
&&

.DISCUSSION...
WEAK HEIGHT RISES WERE NOTED OVER THE REGION PER 12Z SOUNDING DATA 
WITH H5 LEVELS NEAR 582DM...WITH THIS GENERAL TREND CONTINUING 
THROUGH THE WEEKEND AS RIDGING BUILDS OVER THE REGION. H5 HEIGHTS 
NEAR 588DM WILL BE COMMON THROUGHOUT THE FORECAST AREA SATURDAY 
THROUGH MONDAY YIELDING THE WARMEST WEATHER OF THE YEAR. 12Z DATA 
ALSO SHOWED 1C-2C OF WARMING IN THE H8-H7 LAYER VERSUS WEDNESDAY 
MORNING...AND FURTHER HEATING OF THIS LAYER WILL OCCUR INTO THE 
WEEKEND WITH H7 TEMPS PEAKING JUST ABOVE +10C AND H8 TEMPS IN A +25C 
TO +29C RANGE. 

LITTLE IN THE WAY OF UPSTREAM THICK CIRRUS IS NOTED EITHER IN WV 
IMAGERY NOR FORECAST BUFR SOUNDINGS...SUCH THAT NEAR FULL INSOLATION 
WILL MATERIALIZE WITH LITTLE TO NO HINDRANCE TOWARDS A DEEP WELL 
MIXED BOUNDARY LAYER. FORECAST TEMPERATURE SPREAD AMONG OPERATIONAL 
AND ENSEMBLE MEMBERS IS EXTREMELY SMALL YIELDING VERY HIGH 
CONFIDENCE THAT AFTERNOON HIGHS WILL REACH A 102F TO 108F RANGE FOR 
LOWER ELEVATIONS. THIS IS NOT UNCOMMON FOR THIS TIME OF YEAR AND 
WELL SHORT OF HEAT WARNINGS (AVERAGE FIRST 105F DAY FOR PHOENIX AND 
YUMA IS MAY 23RD)...HOWEVER AFTER A PROLONGED PERIOD OF COOLER THAN 
NORMAL WEATHER OVER THE REGION...A PRECAUTIONARY SPECIAL WEATHER 
STATEMENT HAS BEEN ISSUED ALERTING PARTNERS AND CUSTOMERS OF THE HOT 
WEEKEND.
 
NEXT WEEK...THE RIDGE ALOFT WILL EVENTUALLY GET BOOTED INTO THE 
PLAINS AS A FAIRLY LARGE PACIFIC LOW APPROACHES THE WEST COAST LATE 
SUNDAY. MODELS HAVE BEEN INSISTENT THAT A MOISTURE SEEP WILL ADVECT 
WESTWARD TOWARDS FAR EASTERN ARIZONA SUNDAY AFTERNOON...PROVIDING 
ENOUGH INSTABILITY FOR ISOLD THUNDERSTORMS AROUND THE WHITE 
MOUNTAINS AND ALONG THE MOGOLLON RIM. CANNOT DISCOUNT AN ISOLATED 
LIGHTNING STRIKE OVER THE SAN CARLOS REGION OF SRN GILA 
COUNTY...HOWEVER THE CHANCE FOR RAINFALL REACHING THE GROUND IS 
STILL MINIMAL. OTHERWISE...THE OVERALL CONSENSUS AMONG MODELS KEEPS 
ALL OF THE ENERGY MAINLY OVER THE PACIFIC NORTHWEST AND NORTHERN 
ROCKIES...THOUGH SHOULD HELP TO LOWER HEIGHTS SLIGHTLY OVER THE 
SOUTHWEST STARTING MONDAY. THIS WILL HELP TO COOL THINGS OFF 
SLIGHTLY GOING INTO THE MIDDLE OF NEXT WEEK WHERE HIGHS SHOULD DIP 
BACK TO NEAR SEASONAL NORMALS.

&&

.AVIATION... 
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...AND 
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND 
KBLH... 

NO AVIATION CONCERNS THROUGH AT LEAST FRIDAY AFTERNOON UNDER CLEAR 
SKIES. SFC WINDS WILL REMAIN VERY WEAK...AND EXTENDED PERIODS OF 
LIGHT AND VARIABLE OR CALM WINDS WILL BE COMMON. TIMING OF THE 
TYPICAL DAILY WIND SHIFTS WILL BE SOMEWHAT DELAYED VERSUS 
NORMAL...AND SIMILAR TO THE TIMING THE PAST SEVERAL DAYS. 

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
AS HIGH PRESSURE REMAINS SITUATED OVER THE DISTRICT...NORMAL TO 
ABOVE NORMAL TEMPERATURES AND WIDESPREAD DRY WEATHER WILL STAY IN 
PLACE OVER THE DISTRICT THROUGH AT LEAST THE MIDDLE OF NEXT WEEK. A 
FEW ISOLATED THUNDERSTORMS MAY FORM OVER THE WHITE MOUNTAINS AND THE 
RIM SUNDAY AFTERNOON AND APPROACH SRN GILA COUNTY...HOWEVER CHANCES 
FOR RAINFALL REACHING THE GROUND IS MINIMAL. AFTERNOON HIGH 
TEMPERATURES WELL OVER 100F WILL BE COMMON AT LOWER ELEVATION 
LOCATIONS YIELDING MINIMUM RELATIVE HUMIDITY VALUES BELOW 10 PERCENT 
FOLLOWING FAIR OVERNIGHT RECOVERY. SFC WINDS WILL BE PRIMARILY WEAK 
WITH THE USUAL AFTERNOON UPSLOPE GUSTINESS...HOWEVER A PERIOD OF 
SOMEWHAT STRONGER WINDS WILL BE POSSIBLE AROUND THE MIDDLE OF NEXT 
WEEK IN ASSOCIATION WITH A WEATHER DISTURBANCE MOVING NORTH OF THE 
AREA. 

&&  

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

&&

$$

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DISCUSSION...MO/KUHLMAN
AVIATION...MO
FIRE WEATHER...MO

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