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. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...MEYERS/AJ AVIATION...MEYERS FIRE WEATHER...SAWTELLE