Weather Service Report


044 
FXUS65 KPSR 220440
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
940 PM MST TUE OCT 21 2014

.SYNOPSIS...
GRADUAL DRYING WILL OCCUR THIS WEEK...BUT THERE WILL BE ONE LAST DAY 
OF SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS THE MOUNTAINS 
NORTH AND EAST OF PHOENIX TODAY. SOME WARMING IS EXPECTED BY MID 
WEEK...LASTING THROUGH SATURDAY WITH HIGHS 5-10 DEGREES ABOVE 
NORMAL. A COOL DOWN IS EXPECTED TO TAKE PLACE ON SUNDAY INTO EARLY 
NEXT WEEK BRINGING TEMPERATURES BACK TO NEAR SEASONAL NORMALS. 

&&

.DISCUSSION...
SATELLITE IMAGERY SHOWS ONLY VERY MINOR PATCHES OF CIRRUS OVER THE 
FORECAST AREA THIS EVENING ASSOCIATED WITH THE SOUTHERN FRINGES OF A 
PASSING TROUGH. A PACIFIC RIDGE IS ALREADY BEGINNING TO BUILD OVER 
CALIFORNIA. THE RIDGE WILL CONTINUE TO BUILD EASTWARD AND BECOME 
CENTERED OVER ARIZONA AND NORTHWEST MEXICO BY LATE THURSDAY. THE 
RIDGE WILL BE AT ITS STRONGEST FRIDAY WITH THE AXIS CLOSE TO THE 
AZ/NM BORDER. THUS TEMPERATURES WILL BECOME EVEN WARMER ALONG WITH 
CLEAR SKIES. IN FACT...SOME STATIONS WILL BE FLIRTING WITH RECORDS 
ON FRIDAY. 

&&

.PREVIOUS DISCUSSION ISSUED 253 PM...
THE BAND OF MID-HIGH CLOUDS THAT WERE MIGRATING TO THE EAST THIS 
MORNING ACROSS SOUTHERN ARIZONA CONTINUE THEIR TREK THIS AFTERNOON. 
TEMPERATURES SEEM NEARLY UNCHANGED COMPARED TO 24 HRS AGO AND STILL 
ON TRACK TO TOP OUT AROUND 90 ACROSS METRO PHOENIX AND MID TO UPPER 
90S ACROSS SOUTHWEST ARIZONA. THE UPPER LEVEL SHORTWAVE TROUGH 
FEATURE PASSING TO OUR NORTH TODAY WILL HAVE LITTLE IMPACT ACROSS 
OUR CWA AND MAY BRING SOME ISOLATED SHOWERS OR THUNDERSTORMS TO THE 
HIGHER TERRAIN OF NORTHEASTERN ARIZONA. 

PRECIPITABLE WATER VALUES REMAIN JUST BELOW AN INCH WITH DRIER AIR 
UPSTREAM ACROSS CENTRAL CALIFORNIA. WITH THE TROUGH PASSING THROUGH 
THE GREAT BASIN EARLY WEDNESDAY...A NORTHWEST FLOW WILL DRAW IN 
DRIER AIR FROM THE WEST AND RISING HEIGHTS OF 2-4 DM EACH DAY 
THROUGH FRIDAY WILL ALLOW TEMPERATURES TO RISE GRADUALLY. BY FRIDAY, 
PHOENIX WILL FLIRT WITH NEAR RECORD DAYTIME TEMPERATURES (24 OCTOBER 
RECORD STANDS AT 96F SET IN 2007). THE RIDGE OF HIGH PRESSURE 
BUILDING IN FROM THE PACIFIC WILL HEAD INTO THE DESERT 
SOUTHWEST...WITH 500MB HEIGHTS RISING TO 588DM...THROUGH SATURDAY. 
WITH RISING HEIGHTS AND VERY LITTLE MOISTURE TO SPEAK OF...SKIES 
SHOULD REMAIN MOSTLY CLEAR THROUGH FRIDAY WHICH SHOULD BODE WELL FOR 
A PARTIAL SOLAR ECLIPSE SCHEDULED FOR THURSDAY 23 OCTOBER STARTING 
AT 1938Z (1238 PM MST/PDT LOCAL) AND PEAKING AT 2145Z (245PM MST/PDT 
LOCAL). WHILE ARIZONA IS ON THE SOUTHERN CUSP OF BEST VIEWING 
LOCATIONS...SKIES SHOULD REMAIN CLEAR ENOUGH TO VIEW A PARTIAL SOLAR 
ECLIPSE DURING THIS TIME.

A LESS CLEAR PICTURE IS SHOWN FOR THIS WEEKEND INTO EARLY NEXT WEEK 
AS SIGNIFICANT MODEL DIFFERENCES ARE SHOWN FOR SUNDAY AND MONDAY. 
THE EUROPEAN AND THE CANADIAN MODELS ARE NOW SHOWING A FAIRLY STRONG 
PV ANOMALY BREAKING OFF FROM A NORTH PACIFIC LOW AND SLIDING 
SOUTHEASTWARD INTO OR NEAR THE DESERT SOUTHWEST SOMETIME SUNDAY INTO 
MONDAY. THE GFS REMAINS MUCH WEAKER AND FURTHER NORTH WITH THIS 
FEATURE. EITHER WAY...LITTLE TO NO MOISTURE IS CURRENTLY SHOWN TO 
ACCOMPANY THIS POTENTIAL SHORTWAVE TROUGH...BUT WILL HAVE TO MONITOR 
FOR ANY CHANGES OVER FUTURE MODEL RUNS. LONG RANGE MODELS DO AGREE 
THAT AN OVERALL TROUGHING PATTERN WILL TAKE OVER STARTING SUNDAY 
ALLOWING FOR A SIGNIFICANT COOL DOWN...PROBABLY BACK TO NEAR NORMAL 
OR HIGHS IN THE LOWER TO MIDDLE 80S ACROSS THE LOWER DESERTS.        

&&

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

CLEAR SKIES WILL PREVAIL WITH LIGHT WINDS. TYPICAL 
DOWNVALLEY/DRAINAGE PATTERNS CAN BE EXPECTED TONIGHT AND WEDNESDAY 
MORNING. ANTICIPATE LIGHT AND VARIABLE AFTERNOON WINDS BECOMING WEAK 
UPVALLEY BY LATE AFTERNOON. 

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
STRONG HIGH PRESSURE WILL REMAIN OVER THE DISTRICT INTO THE 
WEEKEND...ONLY GRADUALLY WEAKENING BY EARLY NEXT WEEK. AS SUCH...DRY 
WEATHER WITH ABOVE NORMAL TEMPERATURES WILL PREVAIL. MINIMUM 
RELATIVE HUMIDITY VALUES WILL GENERALLY RANGE FROM 15 TO 25 
PERCENT...WITH THE EXCEPTION OF HIGHER VALUES OVER MOUNTAINOUS 
TERRAIN. OVERNIGHT RECOVERY WILL BE GOOD. AFTERNOON WIND SPEEDS WILL 
BE SLIGHTLY STRONGER THAN EXPERIENCED THE PAST WEEK...WITH MORE 
FREQUENT GUSTS NEAR RIDGE TOPS AND THROUGH RIVER VALLEY LOCATIONS. 

 
&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...AJ
PREVIOUS DISCUSSION...DEWEY/KUHLMAN
AVIATION...AJ
FIRE WEATHER...MO




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