FXUS65 KPSR 081644
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
944 AM MST TUE DEC 8 2009
.SYNOPSIS...
DRY WESTERLY FLOW ALOFT WILL CONTINUE TODAY IN THE WAKE OF THE
WINTER STORM. LITTLE CHANGE IS EXPECTED THROUGH WEDNESDAY. A
SLIGHT CHANCE OF SHOWERS IS EXPECTED LATE THURSDAY AND THURSDAY
NIGHT...AND AGAIN SATURDAY AND SATURDAY NIGHT...AS A MOIST PACIFIC
WESTERLY FLOW DEVELOPS.
&&
.DISCUSSION...
UPPER AIR DATA INDICATED THE DRY PUNCH HAS MIXED DOWN TO THE SFC IN
ALL AREAS EARLY THIS MORNING. THE YUMA SOUNDING HAD A MERE .24
PRECIP WATER...WHILE SOME LINGERING RH WAS STILL EVIDENT ON THE
TUCSON SOUNDING...UP TO ABOUT 12 THSD FT.
LOOKING BACK...ONE OF THE HEAVIER PRECIP TOTALS CAME FROM A SITE
ABOUT 4 MILES SOUTH OF GLOBE...3.58 INCHES. BUT THE WINDS WERE THE
MAIN STORY IN THE PHOENIX AREA...WITH ONE OF THE STRONGEST PEAK
WINDS WERE FROM DEER VALLEY AIRPORT...74 MPH.
BOTH 700 AND 500 MB LEVELS HAD DRIED OUT WITH THE NORTHWEST FLOW
TAKING OVER. RUC INDICATED A WEAK IMPULSE NEAR PAGE ARIZONA AND
ANOTHER SERIES OF SYSTEMS EMBEDDED IN A BROAD CYCLONIC FLOW ACROSS
MUCH OF THE WESTERN REGION. NAM/GFS BOTH SHOW NEXT PACIFIC SYSTEM
WILL BE ARRIVING FROM THE EASTERN PAC...WITH A LOT OF ENERGY
UNDERCUTTING THE ALASKAN BLOCK.
TIMING OF THE ONSET OF THIS MOISTURE WILL BE TRICKY WITH MODELS
SHOWING SLIGHT DIFFERENCES IN THE AMPLITUDE OF THE SHORT WAVE. AT
THIS TIME...WE WILL NOT MAKE ANY CHANGES FROM EARLIER FORECASTS AND
KEEP MOST LOCATIONS IN OUR CWA UNDER SLIGHT CHANCES.
PREVIOUS DISCUSSION...
THURSDAY THROUGH SUNDAY...
WE WILL CALL THIS PERIOD...POTENTIALLY UNSETTLED. A MOIST PACIFIC
WESTERLY FLOW DEVELOPS OVER THE SOUTHWESTERN STATES THIS PERIOD...
WITH HARD TO TIME WEAK DISTURBANCES. THEREFORE WE WILL GO WITH A
SLIGHT CHANCE OF SHOWERS FOR THE THURSDAY/THURSDAY NIGHT TIME
FRAME...AND AGAIN IN THE SATURDAY/SATURDAY NIGHT PERIOD.
MONDAY AND TUESDAY...
DRY AND WARMER AS HIGH PRESSURE BUILDS OVER THE AREA.
&&
AVIATION...
STRONG LOW PRESSURE SYSTEM MOVES EAST OF OF AZ AND INTO NM/CO TODAY.
IN ITS WAKE...CONSIDERABLE CLEARING HAD OCCURRED BY 8 AM FROM
PHOENIX WESTWARD...WITH SUNNY SKIES SEEN IN VIS IMAGERY. EXPECT SOME
SCT-BKN LOW CLOUDS FROM 5-8K FT EAST OF PHOENIX MAINLY OVER THE
HIGHER TERRAIN...THRU MID DAY TODAY...BUT ONLY A FEW CU IN THE
KPHX/KINW AREA. A CONSIDERABLY LIGHTER WIND REGIME...WIND DIRECTION
FAVORING THE WEST AT ALL TAF SITES...WITH SPEEDS GENERALLY LESS THAN
12KT TODAY.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
AN UNSETTLED WEATHER PATTERN AS A SERIES OF WEATHER DISTURBANCES
MOVE ACROSS THE REGION. ANTICIPATE COOLER TEMPERATURES...LIGHT WINDS
AND ELEVATED HUMIDITY LEVELS THROUGH THE PERIOD...WITH ANOTHER SHOT
AT PRECIPITATION ACROSS THE AREA CONTINUING INTO THE WEEKEND.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT
WEATHER.GOV/PHOENIX
DISCUSSION...SIPPLE/VASQUEZ
AVIATION...CB
FIRE WEATHER...MEYERS
