Weather Service Report


604 
FXUS65 KPSR 091024
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
324 AM MST TUE FEB 9 2016

 
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER FEATURE OVER THE
SOUTHWESTERN UNITED STATES THIS WEEK. THIS WILL RESULT IN A PROLONGED
PERIOD OF SUNNY SKIES...ABOVE NORMAL TEMPERATURES... RELATIVELY LIGHT
WINDS...AND LOW HUMIDITY.
 
&&

.DISCUSSION...
OUR FIRST OCCURRENCE OF 80F-PLUS IN PHOENIX DID NOT DISAPPOINT
YESTERDAY...WARMING ALL THE WAY UP TO 85F AND ONE DEGREE SHY OF THE
RECORD FOR THE CALENDAR DAY. OTHER SITES AROUND THE AREA WERE
EQUIVALENTLY WARM...YUMA...EL CENTRO AND PARKER AT 83F AND LOWER 80S
FOR NEARLY ALL ACROSS THE LOWER DESERTS. NO SURPRISE THAT GIVEN THE
WARM AFTERNOON AND OVERNIGHT BREEZES TEMPERATURES ARE STILL RUNNING
ON THE WARM SIDE AND 2 TO 4 DEGREES HIGHER THAN THIS TIME MONDAY AM.
CONUS WATER VAPOR IMAGERY OVERNIGHT SHOWS TROUGHING OVER THE
EAST...HIGH AMPLITUDE RIDGING OVER THE WEST COAST AND A SLOW EXITING
UL LOW TO OUR SOUTH OVER BAJA SUR/SONORA/SINALOA. SFC HIGH PRESSURE
NORTH OF THE FOUR CORNERS AND SUBSIDENT NORTHERLY FLOW ALOFT ARE
STILL SET-UP TO PROMOTE NORTHEASTERLY BREEZES ACROSS SOUTH-CENTRAL AZ
AND NORTHERLY BREEZES FOR THE CO RIVER VALLEY.

UNSEASONABLY STRONG RIDGING WILL PERSIST OVER THE WEST FOR THE REST
OF THE WEEK. 1000-500MB THICKNESSES ARE FORECAST TO PEAK FRIDAY
AFTERNOON...WHICH COULD BE OUR WARMEST DAY OF THE WEEK AS THE RIDGE
AXIS CLEARS TO OUR EAST AND SOME MODEST WAA MOVES INTO THE REGION. 
WIDESPREAD LOW TO MID 80 DEGREE READINGS WILL OCCUR FOR MANY LOWER
DESERT SITES...WITH SOME RECORD OR NEAR RECORD VALUES POSSIBLE FOR
BOTH PHOENIX AND YUMA. PLEASE REFERENCE THE UPDATED CLIMATE SECTION
FOR THE FORECAST AND RECORD DETAILS. SWIFT PASSAGE OF THE SOUTHERN
END OF A DRY /FOR US/ PAC NORTHWEST SHORTWAVE MAY SUPPORT A DEGREE OR
TWO OF COOLING FOR SATURDAY AND SUNDAY WITH THE COMBINATION OF
SLIGHTLY LOWER UL HEIGHTS AND SOME HIGH LEVEL CLOUDINESS. RIDGING
QUICKLY REBOUNDS BY EARLY NEXT WEEK AND THE WARMTH AND ABOVE-NORMAL
TEMPERATURES RETURN. HOWEVER...OF CONTINUED INTEREST IS...A SHEARED
PORTION OF THIS PAC NW TROUGH FORMING INTO A CUTOFF LOW OFF THE SAN
DIEGO COAST SUNDAY...DEEPENING SOUTH TO OFFSHORE SOUTHERN BAJA
MONDAY...NEAR THE NORTHERN EDGES OF WARM EL NINO WATERS. THIS AREA
OFFSHORE PRESENTS ALMOST LIKE THE SOUTHERN BRANCH OF A REX
BLOCK...WITH LOWER HEIGHTS/GENERAL WEAKNESS PERSISTING.

PATTERN PREDICTABILITY DROPS OFF AND ENSEMBLE SPREAD INCREASES
TOWARDS THE LATTER END OF THE EXTENDED PERIOD AS SOME TROPICAL
PACIFIC CONVECTION AND JET STREAKING TAKE ADVANTAGE OF THOSE
PERSISTENT LOW HEIGHT ANOMALIES OVER THE EAST PACIFIC/BAJA PENINSULA.
AS THE DAY SHIFT NOTED THIS ATMOSPHERIC SET-UP HAS OCCURRED IN
PREVIOUS EL NINO YEARS /CUTOFF LOWS IN THIS EL NINO REGION HAVE SPUN
UP INCREDIBLY FAST DUE TO THE PHASING OF A SUBTROPICAL JETSTREAM/
RESULTING IN EVENTUAL PRECIP ACTIVITY DOWNSTREAM OVER THE SOUTHWEST
DESERTS. DETERMINISTIC MODEL RUNS ARE BROADLY AGREEING ON THE IDEA
OF STRONGER AND DEEPER PACIFIC TROUGH SWEEPING INTO SOUTHERN WEST
COAST TOWARDS THE LATTER PART OF NEXT WEEK AND MODTREND GUIDANCE
FROM THE GFS POINTS TO SOME PERSISTENT WEAKENING OF 500MB HEIGHTS
OVER THE CENTRAL PACIFIC UPSTREAM BY THU-FRI NEXT WEEK. WE ARE JUST
OUTSIDE THE WINDOW OF GETTING IVT/AR GUIDANCE BUT BROAD MODEL
AGREEMENT ON THE UPPER LEVEL PATTERN NEVER HURTS TO SEE THIS FAR OUT.

&&

.AVIATION... 
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...

HIGH PRESSURE OVER THE 4-CORNERS REGION TO KEEP WINDS FROM AN
EASTERLY DIRECTION AT ALL OF THE PHX AREA TERMINALS THROUGH THE TAF
PERIOD. WIND SPEED WILL REMAIN MAINLY AOB 8 KTS...EXCEPT FOR A
PERIOD OF TIME DURING THE LATE MORNING-EARLY AFTERNOON HOURS ON
TUESDAY WHEN STRONGER WINDS ALOFT MIXING DOWN TO THE SFC INCREASES
SPEEDS A BIT...UP INTO THE 10-12KT RANGE AT KPHX. SKIES TO REMAIN
CLEAR THROUGH THE TAF PERIOD.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...

NORTHERLY BREEZES AT KBLH TO GRADUALLY DIMINISH LATE TONIGHT AND
EARLY TUESDAY AS SFC PRESSURE GRADIENTS WEAKEN OVER THE
REGION WITH WINDS BECOMING LIGHT/VARIABLE BY TUESDAY AFTERNOON.
WINDS AT KIPL TO REMAIN ON THE LIGHT SIDE...MAINLY AOB 8
KTS...FOLLOWING TYPICAL DIURNAL TRENDS. SKIES TO REMAIN MAINLY CLEAR
THROUGH TONIGHT WITH SOME PATCHY CIRRUS CLOUD LAYERS PASSING OVER
THE TERMINALS DURING THE DAY ON TUESDAY.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&& 

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
AN UNSEASONABLY STRONG HIGH PRESSURE RIDGE WILL BUILD OVER THE
WESTERN STATES DURING THE WEEK. THIS WILL LEAD TO A PERSISTENT PERIOD
OF WELL ABOVE NORMALS HIGH TEMPERATURES...WITH READINGS PEAKING 10
TO 15 DEGREES ABOVE SEASONAL NORMALS. MANY LOWER ELEVATION AND DESERT
SITES WILL SEE A STRETCH OF DAYS WITH HIGH TEMPERATURES WARMING PAST
THE 80 DEGREE MARK. RH'S WILL ALSO REMAIN ON THE DRIER AND BELOW
NORMAL SIDE DURING THE WEEK WITH MIN VALUES TYPICALLY IN THE LOW TO
MIDDLE TEENS.

LOCALLY BREEZY CONDITIONS ALONG THE CO RIVER VALLEY ARE EXPECTED
EACH AFTERNOON. MORE NOTICEABLE EASTERLY WINDS WILL FLOW INTO THE
SOUTH-CENTRAL AZ DESERTS...WITH ELEVATED WINDS OVER RIDGETOPS AND
GAPS TO THE NORTH/EAST OF PHOENIX. WINDS ELSEWHERE WILL GENERALLY
FOLLOW TYPICAL DRAINAGE/SLOPE DRIVEN HEADINGS WITH LIGHT SPEEDS. BY
WEEKS END THE UPPER RIDGE WILL BEGIN TO SHIFT TO OUR EAST AS
TROUGHING ALIGNS ITSELF OVER THE WEST COAST AGAIN. SOME VERY SLIGHT
TEMPERATURE COOLING AND INCREASING CLOUDINESS ARE LIKELY OVER THE
WEEKEND.

&&

.CLIMATE...
                   PHOENIX         |        YUMA
             FCST | RECORD (YEAR)  | FCST | RECORD (YEAR)

TUE FEB 9      84 | 84 (1987)      |   84 | 90 (2015) 
WED FEB 10     84 | 87 (1951)      |   84 | 93 (1951) 
THU FEB 11     85 | 83 (1951)      |   85 | 86 (1971)
FRI FEB 12     86 | 84 (1988)      |   85 | 87 (1957)
SAT FEB 13     86 | 88 (1957)      |   85 | 93 (1957)
SUN FEB 14     83 | 85 (2014)      |   83 | 94 (1957)

&&

.SPOTTER INFORMATION STATEMENT... 
SPOTTERS ARE ENCOURAGED TO REPORT BASED ON STANDARD OPERATING
PROCEDURES.

&&

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

$$

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

DISCUSSION...NOLTE
AVIATION...PERCHA
FIRE WEATHER...NOLTE/CB
CLIMATE...NOLTE

Return to Home page


Western Regional Climate Center, wrcc@dri.edu