Area Forecast Discussion
Issued by NWS Phoenix, AZ

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FXUS65 KPSR 211929 CCA
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1225 PM MST FRI NOV 21 2014

.UPDATE...UPDATE AVIATION AND FIRE WEATHER DISCUSSIONS

&&

.SYNOPSIS...
A PACIFIC WEATHER SYSTEM WILL MOVE QUICKLY EAST ACROSS ARIZONA
TODAY...BRINGING MOSTLY CLOUDY SKIES...SLIGHTLY COOLER TEMPERATURES
AND A SLIGHT CHANCE OF SHOWERS. MOSTLY CLEAR AND DRY CONDITIONS WITH
NEAR NORMAL TEMPERATURES WILL RETURN OVER THE WEEKEND...THEN LINGER
INTO EARLY NEXT WEEK. HIGHER PRESSURE ALOFT WILL BUILD INTO THE
DESERT SOUTHWEST BY THE MIDDLE OF NEXT WEEK ALLOWING FOR HIGH
TEMPERATURES TO CLIMB A FEW DEGREES ABOVE SEASONAL NORMALS.

&&

.DISCUSSION...
QUICK UPDATES WERE MADE TO FORECASTS TO INCLUDE A SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS ACROSS A LARGE SWATH FROM SOUTHEAST CA TO
SOUTH CENTRAL AZ...INCLUDING PHOENIX. ONE LOOK AT THE UPPER AIR DATA
SORT OF GAVE US THE HEEBEE JEEBEES. THE APPROACHING SMALL...BUT
DYNAMICALLY STRONG TROF...WITH LIMITED MOISTURE...HAS THE POTENTIAL
TO PRODUCE AT LEAST A SLIGHT CHANCE OF HIGH BASED SHOWERS AND
THUNDERSTORMS. RAPIDLY COOLING MID LEVEL TEMPERATURES TODAY...
STRONG H5/H3 HEIGHT FALLS DIRECTED AT GILA BEND...AND STRONG
DIFLUENCE ALOFT WILL TRY TO SQUEEZE THE ATMOSPHERE DRY SO TO SPEAK.
EARLIER THIS MORNING THERE WERE A NUMBER OF LIGHTNING STRIKES IN
SOUTHEAST CA...AND IT WAS RAINING LIGHTLY IN YUMA AT 7 AM.  STRONG
HEIGHT RISES ALONG THE WEST COAST SUGGEST THIS IS A FAST MOVING
SYSTEM...AND PRECIP PROBABILITIES SHOULD DIMINISH RAPIDLY LATER THIS
AFTERNOON...CLEARING OVERNIGHT.

OTHERWISE...REMAINDER OF FORECASTS FOR THE WEEKEND LOOK OK.


.PARTS OF PREVIOUS DISCUSSION...530 AM MST...
AS THE UPPER LOW QUICKLY EXITS TO THE EAST/SOUTHEAST TONIGHT...SERN
CA AND AZ WILL COME UNDER A COOL...DRY AND SUBSIDENT NWLY FLOW
ALOFT. SOME HIGH CLOUDS WILL SPREAD IN FROM THE NORTHWEST SATURDAY
FOR PARTLY TO MOSTLY SUNNY SKIES...AND HIGH TEMPS WILL STAY NEAR
SEASONAL NORMAL LEVELS WITH A HIGH OF 72 FORECAST FOR PHOENIX.

FOR SUNDAY INTO THE MIDDLE OF NEXT WEEK...GUIDANCE AGREES THAT A DRY
NORTHWEST FLOW ALOFT WILL BE THE RULE EACH DAY...AS HIGH PRESSURE
GRADUALLY BUILDS INTO THE AREA FOR MOSTLY SUNNY DAYS AND MOSTLY
CLEAR NIGHTS. SOME SHORTWAVE ENERGY PASSING THROUGH THE FOUR CORNERS
AREA SUNDAY WILL BRING ANOTHER SHOT OF COOLER AIR TO THE REGION...
ALLOWING TEMPS MONDAY TO FALL BACK SLIGHTLY...MAINLY OVER SOUTH
CENTRAL AZ. HIGHS WILL DROP BACK INTO THE UPPER 60S OVER THE LOWER
CENTRAL DESERTS MONDAY WITH PHOENIX TO SEE A HIGH AROUND 69. AFTER
THAT...A SLOW WARMING TREND IS EXPECTED WITH HIGHS RISING INTO THE
MID 70S BY WEDNESDAY OVER THE WARMER LOWER DESERTS UNDER MOSTLY
SUNNY SKIES.

&&

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

FAST MOVING UPPER LEVEL LOW WILL MOVE SOUTHEAST ACROSS SOUTH-CENTRAL
ARIZONA THIS AFTERNOON...WITH ISOLATED SHOWERS/THUNDERSTORMS
EXPECTED THROUGH THE AFTERNOON. CLOUD BASES WILL CONTINUE TO LOWER
TO ABOUT 10 KFT MSL BEFORE CLEARING FROM WEST TO EAST AFTER 23Z.
ANTICIPATE AREAS OF VIRGA WITH PRECIP REACHING THE GROUND ONLY OVER
THE HIGHER TERRAIN. WINDS WILL BE LIGHT AT ALL TAF SITES...GENERALLY
10KT OR LESS...WITH LOCAL GUSTS UP TO 30KT POSSIBLE IN VICINITY OF
STRONGER CELLS/STORMS. EXPECT MOSTLY CLEAR SKIES AND LIGHT WINDS
OVERNIGHT THROUGH AT LEAST 16Z SATURDAY MORNING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
GUSTY NORTHERLY WINDS WILL DEVELOP OVER PORTIONS OF SOUTHEAST
CALIFORNIA AND SOUTHWEST ARIZONA SUNDAY AS A DRY COLD FRONT PUSHES
THROUGH THE FORECAST AREA...BRINGING IN MUCH DRIER AIR AND FORCING
MINIMUM HUMIDITY LEVELS TO BOTTOM OUT IN THE TEENS FOR THE REMAINDER
OF THE WEEK. CONDITIONS MAY BRIEFLY REACH CRITICAL THRESHOLDS IN
ISOLATED SPOTS SUNDAY...MAINLY ALONG PORTIONS OF THE COLORADO RIVER
VALLEY WHERE WINDS ARE ANTICIPATED TO BE THE STRONGEST. WINDS STAY
ELEVATED OVERNIGHT AT RIDGETOPS BUT WILL WEAKEN ON THE VALLEY
FLOORS. WARMER TEMPERATURES AND LIGHT WINDS WILL PREVAIL MONDAY
THROUGH THURSDAY AS HIGH PRESSURE BUILDS OVER THE DESERT SOUTHWEST.
OVERNIGHT RECOVERY WILL SHOW LITTLE IMPROVEMENT...REMAINING POOR TO
FAIR THROUGH THE END OF THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX

DISCUSSION...VASQUEZ/CB
AVIATION...MEYERS
FIRE WEATHER...MEYERS





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