Area Forecast Discussion
Issued by NWS Phoenix, AZ

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000
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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