Area Forecast Discussion
Issued by NWS Phoenix, AZ

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FXUS65 KPSR 242018 AAA
AFDPSR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PHOENIX AZ
118 PM MST THU APR 24 2014

.UPDATE...UPDATED AVIATION AND FIRE WEATHER DISCUSSIONS...

&&

.SYNOPSIS...
WARMER TEMPERATURES ARE EXPECTED TODAY AND FRIDAY. HOWEVER
CONSIDERABLE HIGH CLOUDS AND BREEZY CONDITIONS FRIDAY...WILL SIGNAL
THE APPROACH OF A STRONG COLD FRONT FOR SATURDAY MORNING. THE COLD
FRONT SATURDAY WILL PRODUCE VERY WINDY CONDITIONS ACROSS THE
REGION...ALONG WITH AREAS OF BLOWING DUST AND SAND. A CHANCE OF
SHOWERS AND POSSIBLY A THUNDERSTORM WILL DEVELOP MAINLY OVER
PORTIONS OF SOUTH CENTRAL ARIZONA NEAR PHOENIX. MUCH COOLER
TEMPERATURES ARE ALSO EXPECTED SATURDAY. DRY WEATHER...WITH A SLOW
WARMING TREND WILL DEVELOP SUNDAY THROUGH THE MIDDLE OF NEXT WEEK.

&&

.DISCUSSION...
WATER VAPOR IMAGERY SHOWS SHORT WAVE RIDGE PASSING OVER OUR FORECAST
AREA TODAY FOR LIGHTER WINDS AND WARMER TEMPERATURES TODAY.
UPSTREAM...A PACIFIC SYSTEM HAS ALREADY BEGUN PUSHING INTO THE
PACIFIC NORTHWEST. AS THE SYSTEM GETS CLOSER TO OUR AREA...BREEZY TO
WINDY CONDITIONS WILL DEVELOP FRIDAY AFTERNOON. STRONGEST WINDS WILL
BE IN OUR WESTERN AREAS. THUS THE FIRE WEATHER WATCH. THE COLD FRONT
WILL PUSH THROUGH SOUTHEAST CALIFORNIA AND ARIZONA FRIDAY NIGHT AND
SATURDAY MAINTAINING BREEZY/WINDY CONDITIONS. CURRENT POPS COVER THE
WINDOW OF OPPORTUNITY FAIRLY WELL BUT SOME FURTHER ADJUSTMENTS MAY
NEED TO BE MADE AS THE LATEST GFS IS STRONGER WITH THE QG FORCING.
MUCH COLDER TEMPS SATURDAY STILL LOOKS GOOD. MORE LATER.

&&

.PREVIOUS DISCUSSION ISSUED 300 AM...
NOTE: A STRONG COLD FRONT WILL PRODUCE HIGH WINDS IN SOUTHEAST CA
LATE FRIDAY NIGHT/SATURDAY MORNING...AND VERY WINDY CONDITIONS
ELSEWHERE IN SOUTHWEST AND SOUTH CENTRAL AZ SATURDAY MORNING.

TODAY AND FRIDAY...
A SHORTWAVE RIDGE TODAY WILL PRODUCE NEARLY CLOUDLESS SKIES AND
SLIGHTLY ABOVE NORMAL AFTERNOON TEMPERATURES...I.E. LOWER 90S ON THE
DESERTS.  ON FRIDAY...CONSIDERABLE HIGH CLOUDS...SLIGHTLY WARMER
TEMPERATURES...AND AFTERNOON BREEZES WILL DEVELOP. HIGH CLOUDS AND
BREEZES WILL SIGNAL THE APPROACH OF A STRONG PACIFIC TROF/COLD FRONT
FOR SATURDAY.

SATURDAY...
MODELS CONTINUE TO MOVE A POTENT SPRING STORM INTO ARIZONA SATURDAY.
WE PREFER THE GFS SOLUTION FOR SEVERAL REASONS. ONE...THE WAVE
PATTERN OVER THE PACIFIC IS PROGRESSIVE. TWO...A STRONG SPLIT FLOW
ALOFT DEVELOPS JUST OFF THE WEST COAST LIMITING AN OVERLY DEEP
DIGGING TROF. THREE...THE CENTRAL AND EASTERN U.S. IS FREE FROM ANY
BLOCKING SYSTEMS DOWNSTREAM.

THE MAGNITUDE OF THE GFS 12 HR 500 MB HEIGHT FALLS...NEARLY 200
METERS OVER JOSHUA TREE N.P. ZONE 30 AT 12Z SAT...AND ANOTHER 160
METERS NEAR PRESCOTT JUST BEFORE 18Z INDICATE SIGNIFICANT MASS FIELD
CHANGES.THEREFORE...THE GREATEST IMPACT OVER OUR FORECAST AREA WILL
BE WIND. GUSTS BETWEEN 35 AND 50 MPH ARE LIKELY IN SOUTHEAST CA LATE
FRIDAY NIGHT/EARLY SATURDAY MORNING WITH THE COLD FRONT. GUSTY WINDS
IN THE 30 TO 45 MPH RANGE WILL SPREAD TOWARD PHOENIX BY LATE
SATURDAY MORNING/EARLY AFTERNOON. AREAS OF BLOWING DUST AND SAND ARE
EXPECTED.

STRONG VERTICAL MOTION/UPPER LEVEL STORM DYNAMICS WILL MOSTLY BE
CONFINED TO AREAS SKIRTING THE FAR NORTHERN PORTIONS OF OUR
FORECAST AREA...I.E. THE NORTHERN PORTIONS OF LA PAZ...NORTHERN
MARICOPA...AND NORTHERN GILA COUNTIES. THESE AREAS COULD SEE A
THREAT OF SHOWERS AND POSSIBLE THUNDERSTORM. THE BEST CHANCE OF
SHOWERS HOWEVER WILL DEVELOP OVER SOUTHERN GILA COUNTY.

THIS IS A FAST MOVING TROF STORM MOST STORM SUPPORT FORECAST TO MOVE
INTO NORTHWEST NEW MEXICO BY EARLY SATURDAY EVENING.

SUNDAY AND MONDAY...
DRY NORTHWEST FLOW ALOFT WITH NEARLY CLOUDLESS SKIES...LIGHTER
WIND...AND SLOWLY WARMING AFTERNOON TEMPERATURES ARE EXPECTED THIS
PERIOD.

TUESDAY THROUGH FRIDAY...
DRY WEATHER WITH ABOVE NORMAL TEMPERATURES ARE FORECAST. THE ONLY
CAVEAT WILL BE GUSTY NORTH WINDS OVER THE FORECAST AREA...ESPECIALLY
DOWN THE COLORADO RIVER VALLEY TUESDAY AND WEDNESDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
NO WEATHER RELATED AVIATION CONCERNS THROUGH LATE FRIDAY MORNING AS
LIGHT DIURNALLY DRIVEN WINDS ARE EXPECTED AT ALL SITES. ASIDE FROM A
FEW HIGH CLOUDS...SKIES WILL BE MOSTLY CLEAR THROUGH 18Z FRIDAY.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
NO AVIATION CONCERNS FOR THE MAJORITY OF THE TAF PERIOD...BUT WINDS
WILL BEGIN TO INCREASE OUT OF THE SSW ON FRIDAY IN ADVANCE OF AN
APPROACHING LOW. EXPECT SPEEDS IN THE 15G25KT RANGE JUST AFTER THE
END OF THE TAF PERIOD WITH EVEN STRONGER VALUES TOWARD 00Z SATURDAY.
CLOUDS WILL ALSO BE ON THE INCREASE BUT SHOULD REMAIN AOA 25KFT
THROUGH FRIDAY AFTERNOON.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
CONDITIONS WILL QUIET DOWN ON SUNDAY ALTHOUGH THERE COULD STILL BE
SOME BREEZINESS EAST OF PHOENIX SUNDAY AFTERNOON. LIGHT WINDS ARE
THEN EXPECTED THROUGH THE MIDDLE OF NEXT WEEK ALONG WITH INCREASING
TEMPERATURES AND DECREASING HUMIDITIES. OVERNIGHT RECOVERIES WILL BE
FAIR. GIVEN THE LIGHT WINDS...CRITICAL THRESHOLDS SHOULD NOT BE
REALIZED NEXT WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...RED FLAG WARNING FROM NOON TO 8 PM MST FRIDAY AZZ020-025.

CA...RED FLAG WARNING FROM NOON TO 8 PM PDT FRIDAY CAZ031.

$$

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

DISCUSSION...AJ
PREVIOUS DISCUSSION...VASQUEZ
AVIATION...LEINS
FIRE WEATHER...LEINS





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