Area Forecast Discussion
Issued by NWS Phoenix, AZ

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS65 KPSR 032054
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
154 PM MST WED JUN 3 2015

.SYNOPSIS...
LOW PRESSURE WILL MOVE INTO THE REGION LATER THIS WEEK...BRINGING A
SLOW COOLING TREND TO THE AREA THROUGH THE END OF THE WEEK. MANY
DESERT LOCATIONS WILL SEE DAYTIME HIGHS IN THE MID 90S BY FRIDAY.
THIS SAME LOW PRESSURE SYSTEM WILL ALSO DRAW TROPICAL MOISTURE
NORTHWARD INTO THE AREA RESULTING IN INCREASED CHANCES OF SHOWERS AND
THUNDERSTORMS LATE THURSDAY AND FRIDAY. UNSETTLED CONDITIONS ARE
EXPECTED TO PERSIST THROUGH THE WEEKEND INTO EARLY NEXT WEEK.

&&

.DISCUSSION...
ONE MORE QUIET DAY BEFORE TYPICAL EARLY JUNE DRY WEATHER TURNS INTO A
LIKELY RARE RAIN EVENT. CURRENT SATELLITE IMAGERY CONTINUES TO SHOW
CLEAR SKIES REGION WIDE WITH A PACIFIC TROUGH APPROACHING THE WEST
COAST. OVER THE NEXT 24 HOURS...THIS TROUGH WILL DEEPEN AND BECOME
CLOSED OFF OVER NORTHERN CALIFORNIA WHILE DROPPING HEIGHTS ACROSS THE
DESERT SOUTHWEST. FOR THURSDAY...THIS DROP IN HEIGHTS WILL ALLOW FOR
A FEW DEGREES OF COOLING ACROSS SOUTHEAST CALIFORNIA TO MAYBE A
DEGREE OVER SOUTH-CENTRAL ARIZONA. BY LATE THURSDAY...THE CLOSED LOW
WILL BEGIN TO SHIFT MORE SOUTHWARD WITH THE FORECASTED LOW CENTER
JUST NORTH OF LOS ANGELES.

STRONG SOUTH SOUTHWESTERLY FLOW AROUND THE LOW WILL DRAW UP MID AND
UPPER LEVEL MOISTURE FROM THE REMNANTS OF TROPICAL STORM ANDRES AND
EVENTUALLY PULL IN LOW LEVEL MOISTURE OFF THE PACIFIC ACROSS EASTERN
ARIZONA FRIDAY MORNING. THIS AMOUNT OF MOISTURE WILL LIKELY BE
CLIMATOLOGICALLY ON PAR WITH VALUES OFTEN SEEN IN MID JULY. OVERALL
MODEL CONSISTENCY REMAINS FAIRLY GOOD...BUT THERE ARE STILL SOME
DIFFERENCES WHERE AND EXACTLY WHEN THE MAIN RAIN BAND SETS UP LATE
THURSDAY INTO FRIDAY. ANY RAINFALL FOR THE LOWER DESERTS THIS TIME OF
YEAR IS RARE AND IN FACT THE RECORD RAINFALL FOR KPHX FOR FRIDAY IS
0.00 INCHES. THE AXIS OF HIGHEST PRECIPITABLE WATER
VALUES...1.00-1.25 INCHES...STILL LOOKS LIKE IT WILL FALL SOMEWHERE
BETWEEN PHOENIX AND GLOBE...AND LOCATIONS TO THE WEST WILL LIKELY BE
DRY SLOTTED THROUGHOUT THE EVENT.

AS THE INITIAL SURGE OF MOISTURE GETS DRAWN INTO THE DESERT SOUTHWEST
LATER ON THURSDAY...THE DRY AIR ALREADY IN PLACE WILL CAUSE THIS
INITIAL SURGE TO MAINLY GO INTO PRE-CONDITIONING THE ATMOSPHERE AS IT
SATURATES FROM THE TOP DOWN. WE MAY SEE SOME VIRGA SHOWERS STARTING
LATE THURSDAY AFTERNOON INTO THE EVENING HOURS SOUTH AND EAST OF
PHOENIX WHILE THE ATMOSPHERE IS GRADUALLY GETTING MOISTENED. FORECAST
SOUNDINGS AREN/T SUPPORTIVE OF RAINFALL AROUND THE PHOENIX AREA UNTIL
LATER IN THE EVENING. POPS REMAIN IN THE SLIGHT CHANCE CATEGORY BEFORE
MIDNIGHT AND THEN INCREASE INTO FRIDAY WITH BEST CHANCE OVER THE
HIGH TERRAIN NORTH AND EAST OF PHOENIX FOR FRIDAY AFTERNOON.

QPF GUIDANCE SUGGEST THE GREATEST AMOUNTS...UP TO A COUPLE TENTHS OF
AN INCH...WILL BE IN THE HIGHER TERRAIN LOCATIONS...WITH GENERALLY
LESS THAN A TENTH OF AN INCH OVER THE SOUTH-CENTRAL DESERTS. LOCALIZED
HEAVIER RAINFALL AMOUNTS CANNOT BE RULED OUT WITH INDIVIDUAL T-STORMS
AND WITH THE POTENTIAL FOR A QUASI-STATIONARY PERSISTENT RAIN BAND
ON FRIDAY.

MOST OF THE MOISTURE WILL SCOUR OUT OF THE AREA ON SATURDAY AND AT
THIS POINT IT LOOKS LIKE OUTSIDE OF A FEW AFTERNOON SHOWERS OVER
HIGHER TERRAIN LOCATIONS...THE REMAINDER OF THE REGION SHOULD BE DRY
THIS WEEKEND. FORECAST SOUNDINGS FROM THE LATEST DETERMINISTIC MODELS
AS WELL AS ENSEMBLE GUIDANCE ALSO SUPPORT THIS LINE OF THINKING.

HURRICANE BLANCA IS FORECAST TO MOVE INTO SOUTHERN BAJA BEFORE
DISSIPATING SOMETIME EARLY NEXT WEEK. WHILE THERE WON/T BE AS DEEP
OF A TROUGH OFF THE WEST COAST TO PULL MOISTURE NORTHWARD...THERE/S
STILL A GOOD CHANCE THAT AT LEAST SOME OF THAT MOISTURE WILL BE
ADVECTED INTO ARIZONA TUESDAY/WEDNESDAY OF NEXT WEEK. IN TERMS OF
MOISTURE TRANSPORT AND PRECIPITABLE WATER THERE IS STILL QUITE A BIT
OF SPREAD AMONG THE DETERMINISTIC MODELS. GEFS AND NAEFS SUGGEST A
PERIOD OF ELEVATED POPS AND UNSETTLED WEATHER RETURNING TUESDAY
THROUGH MID WEEK. FOR NOW...WELL ABOVE CLIMO POPS ARE IN THE FORECAST
FOR THIS PERIOD AND MAY HAVE TO BE RAISED OVER THE NEXT COUPLE DAYS.

&&

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

A DEVELOPING UPPER LEVEL TROF ALONG THE WEST COAST WILL KEEP A DRY
SOUTHWEST FLOW ALOFT IN PLACE OVER THE LOWER DESERTS THROUGH THE
AFTERNOON HOURS ON THURSDAY AND AS SUCH SKIES WILL BE GENLY CLEAR AT
THE TAF SITES FOR THE NEXT 24 HOURS. FOR THE CENTRAL AZ DESERTS
WINDS WILL MOSTLY FOLLOW NORMAL DIURNAL TENDENCIES...AND THERE WILL
BE SOME GUSTINESS DURING THE AFTERNOON AND EARLY EVENING HOURS WITH
PEAK GUSTS IN EXCESS OF 20KT POSSIBLE. WINDS SHOULD TURN FROM THE
SOUTHWEST/WEST BACK TO THE EAST/SOUTHEAST AFTER MIDNIGHT TONIGHT.
OUT WEST...EXPECT WINDS AT KIPL TO PERSIST FROM THE WEST AND STAY
RATHER GUSTY THROUGH MIDNIGHT WITH A FEW PEAK GUSTS TO APPROACH 30KT
AFTER 01Z THIS EVENING. WINDS SHOULD TAPER OFF AFTER MIDNIGHT BUT
MAY STAY LOCALLY BREEZY INTO THE MORNING HOURS ON THURSDAY. LOCALLY
BREEZY SOUTH TO SOUTHWEST WINDS ARE EXPECTED AT KBLH...BECOMING
LIGHTER AFTER MIDNIGHT AND THEN BECOMING SOMEWHAT LIGHT/VARIABLE BY
12Z THU.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...

AN AREA OF WEAK LOW PRESSURE WILL PERSIST OVER CALIFORNIA THROUGH
THE WEEKEND AND EARLY NEXT WEEK...BUT THE MOISTURE ASSOCIATED WITH
ANDRES WILL SHIFT EAST AND HUMIDITY VALUES WILL DROP OFF. MINIMUM RH
VALUES OVER THE WEEKEND WILL RANGE FROM THE SINGLE DIGITS TO THE LOW
TEENS FOR THE MOST PART...AND TEMPERATURES WILL STAY NEAR SEASONAL
NORMALS. NO STRONG WINDS ARE EXPECTED OVER THE WEEKEND ALTHOUGH IT
WILL BE LOCALLY BREEZY SATURDAY AFTERNOON ACROSS SOUTH CENTRAL
ARIZONA. MOISTURE ASSOCIATED WITH HURRICANE BLANCA IS EXPECTED TO
MOVE NORTH AND INTO THE AREA SOMETIME DURING THE FIRST HALF OF NEXT
WEEK...LEADING TO AN UNSETTLED PERIOD WITH INCREASING CLOUDS AND
HUMIDITY AND A THREAT FOR SHOWERS OR THUNDERSTORMS. THE BEST THREAT
FOR PRECIP MAY OCCUR DURING THE DAY ON TUESDAY ALTHOUGH THE TIMING
IS STILL UNCERTAIN. TEMPERATURES WILL STAY NEAR SEASONAL NORMALS BUT
WILL LIKELY FALL BELOW NORMAL WHEN THE MOISTURE...CLOUDS AND SHOWERS
FROM BLANCA ARRIVE. WINDS WILL STAY RATHER LIGHT WITH TYPICAL
AFTERNOON GUSTINESS...BUT THEY WILL BE STRONGER...GUSTY AND VARIABLE
SHOULD ANY THUNDERSTORMS DEVELOP.

&&

.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT ANY SIGNIFICANT WEATHER CONDITIONS
ACCORDING TO STANDARD OPERATING PROCEDURES.

&&

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

$$

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

DISCUSSION...KUHLMAN/LEINS
AVIATION...CB
FIRE WEATHER...CB



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.