390 
FXUS65 KPSR 070433
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
930 PM MST WED APR 6 2016

.SYNOPSIS... 
AFTER THE WARMEST TEMPERATURES OF THE YEAR SO FAR...AN UNSETTLED
WEATHER PATTERN WILL RETURN TO THE DESERT SOUTHWEST THURSDAY AND
CONTINUE WELL INTO NEXT WEEK. THIS WILL LEAD TO MUCH COOLER
TEMPERATURES ALONG WITH DECENT CHANCES FOR RAINFALL.

&&

.DISCUSSION...
TONIGHT THROUGH FRIDAY...CIRRUS CONTINUES TO OVERSPREAD THE REGION
AHEAD OF AN UPPER LEVEL LOW THAT IS CURRENTLY WEST OF THE BAJA
PENINSULA. THE LOW IS PROGGED TO GRADUALLY TRACK TO THE NORTHEAST
OVER THE NEXT 24-36 HOURS...ALLOWING YET ANOTHER UPPER LEVEL TROUGH
TO FILL IN BEHIND IT AND REMAIN OFF THE SOUTHERN CALIFORNIA COAST BY
SATURDAY. CLOUDS WILL CONTINUE TO THICKEN OVERNIGHT WITH POPS
DEVELOPING FROM WEST TO EAST ACROSS OUR FORECAST AREA DURING THE DAY
THURSDAY. WITH THE THICKENING CLOUD COVER...OVERNIGHT SURFACE
TEMPERATURES WILL BE MORE MILD...THE TEMP TREND CURRENTLY RUNNING
ABOUT 4-6 DEGREES WARMER THAN THIS TIME YESTERDAY EVENING...AND LOWS
BY TOMORROW MORNING ARE ONLY EXPECTED TO DROP INTO THE UPPER 60S TO
NEAR 70 DEGREES AT WARMER URBAN SITES. CONSIDERABLY DRIER AIR HAS
ALSO INFILTRATED THE LOWER LEVELS ACROSS PORTIONS OF OUR CWA...
REFLECTED IN DEW POINT TEMPS THAT HAVE DROPPED 8-11 DEGREES IN THE
LAST 24 HOURS WITH HUMIDITY LEVELS IN THE SINGLE DIGITS/TEENS IN
MANY AREAS. 

AS THE SYSTEM MOVES IN IT WILL WEAKEN AND THUS THE DYNAMICAL FORCING
AND MOIST ADVECTION ARE NOT OVERLY IMPRESSIVE. OF THE DYNAMICAL LIFT
THAT DOES COME THROUGH...THURSDAY AFTERNOON AND EVENING APPEARS TO
BE THE PEAK TIMING. WITH COOLING ALOFT DURING THE DAY FRIDAY...THERE
LOOKS TO BE SOME MODEST CAPE. BEST PRECIP CHANCES FOR PHOENIX AREA
LOOK TO BE THURSDAY NIGHT AND FRIDAY MORNING. QPF TOTALS THROUGH
FRIDAY NIGHT ARE GENERALLY ONE TENTH TO ONE QUARTER INCH WITH SOME
SPOTS ROUGHLY BETWEEN ONE QUARTER AND ONE HALF INCH. PHOENIX AREA
SHAPING UP TO BE BELOW ONE QUARTER INCH. OF NOTE...THINGS ARE
LOOKING SHOWERY IN NATURE SO THERE WILL BE BIG VARIATIONS IN PRECIP
FROM ONE PLACE TO ANOTHER AND THUS QPF IS BROAD AREAL AVERAGING. THE
OTHER BIG STORY SO TO SPEAK WILL BE THE COOLING TREND WITH HIGHS IN
THE UPPER 70S TO LOW 80S BY FRIDAY. 

SATURDAY AND SUNDAY...
BY AND LARGE WE WILL BE BETWEEN SYSTEMS ON SATURDAY WITH HIGHS
WARMING AT LEAST A FEW DEGREES. THE NEXT SYSTEM...MOVES ACROSS
SOUTHEAST CALIFORNIA AND ARIZONA LATE SATURDAY NIGHT INTO SUNDAY
NIGHT. THIS SYSTEM WILL BE COLDER AND HAVE MORE DISTINCT Q FORCING
AND A FRONTAL BOUNDARY THUS POPS ARE HIGHER...THOUGH PWAT VALUES ARE
NOT AS HIGH. STARTED MENTION OF SLIGHT CHANCE FOR THUNDERSTORMS
SOONER IN THE DAY ON SUNDAY. NO MAJOR PRECIP EVENT WITH THIS ONE
EITHER BUT WE WILL TAKE WHAT WE CAN GET. HIGHS DIP WELL DOWN INTO THE
70S SUNDAY. 

MONDAY THROUGH WEDNESDAY...
MODELS INDICATE A COUPLE MORE SYSTEMS DURING THE FIRST HALF OF THE
NEXT WORKWEEK. OF COURSE THERE ARE VARYING SOLUTIONS ON THE
TIMING...TRACK...INTENSITY...ETC. THIS WILL KEEP LINGERING SLIGHT
CHANCES GOING AS WELL AS BELOW NORMAL TEMPERATURES.  

&&


&&

.AVIATION...

SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
EXPECT SCATTERED TO BROKEN CLOUD DECKS TO GRADUALLY LOWER
OVERNIGHT TO AROUND 12KFT...AND PERSIST MOST OF THE DAY THURSDAY.
SURFACE WINDS WILL BE LIGHT OUT OF THE WEST AND NORTH UNTIL AROUND
07Z...THEN BECOMING MORE EASTERLY THROUGH 16Z THURSDAY
MORNING...WITH LOCAL GUSTS UP TO 15-20KT LATER IN THE AFTERNOON.
ANTICIPATE THAT BEST WINDOW AND TIMING FOR SHOWERS TO MATERIALIZE IN
THE VICINITY OF TERMINALS WILL BE LATE THURSDAY AFTERNOON OR EARLY
EVENING...AFTER 23Z.  

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
EXPECT SCATTERED TO BROKEN CLOUD DECKS TO GRADUALLY LOWER
OVERNIGHT TO AOA 10KFT...AND PERSIST MOST OF THE DAY THURSDAY.
SURFACE WINDS WILL REMAIN SOUTHWEST-WEST OVERNIGHT THROUGH AT LEAST
16Z THURSDAY...THEN BECOMING MORE SOUTHEASTERLY AFTER 16Z
THURSDAY....WITH LOCAL GUSTS UP TO 15-20KT POSSIBLE INTO THE
AFTERNOON HOURS. ANTICIPATE BEST WINDOW FOR SHOWERS TO DEVELOP
OVER THE AREA SOMETIME AFTER 17Z THURSDAY MORNING. 


AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

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

A SERIES OF WEATHER SYSTEMS WILL INTRODUCE A MOIST AIRMASS AND
PERIODIC CHANCES OF WETTING RAINS TO THE REGION THROUGH WEDNESDAY.
AFTERNOON HUMIDITY LEVELS WILL INCREASE TO A 20 TO 40 PERCENT RANGE
BY SUNDAY AND DECREASE TO THE TEENS TO 20S BY WEDNESDAY WITH GOOD TO
EXCELLENT OVERNIGHT RECOVERIES. THE BEST CHANCES FOR RAINFALL...AN
ISOLATED EMBEDDED THUNDERSTORM...AND WET FUELS WILL BE SUNDAY BUT
LINGER ON MONDAY THROUGH TUESDAY MORNING. ONLY OCCASIONAL BREEZY
SOUTHWEST WINDS WILL BE POSSIBLE WITH EACH PASSING WEATHER
DISTURBANCE...ALTHOUGH FIRE DANGER WILL BE SOMEWHAT MINIMAL IN THIS
OVERALL WETTER WEATHER PATTERN.

&&

.SPOTTER INFORMATION STATEMENT... 
SPOTTER ACTIVATION IS NOT EXPECTED.

&&

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

$$

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DISCUSSION...MEYERS/AJ
AVIATION...MEYERS
FIRE WEATHER...SAWTELLE