692
FXUS65 KFGZ 071636
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
936 AM MST SAT NOV 7 2009
SYNOPSIS
HIGH PRESSURE WILL WEAKEN OVER THE NEXT SEVERAL DAYS AS
A SERIES OF WEATHER DISTURBANCES MOVE ACROSS THE GREAT BASIN. THE
MAIN IMPACTS FROM THESE DISTURBANCES WILL BE PERIODS OF CLOUDS AND A
GRADUAL COOLING TREND. IN THE EXTENDED...A PACIFIC COLD FRONT MAY
BRING A SLIGHT CHANCE OF SHOWERS STARTING THURSDAY OR FRIDAY OF NEXT
WEEK.
DISCUSSION
SATELLITE IMAGERY CURRENTLY SHOWS AN UPPER LEVEL LOW
CENTERED OVER SONORA, MEXICO. THIS UPPER LOW WILL CONTINUE TO MOVE
OFF TO THE EAST THROUGHOUT THE DAY. THERE IS CURRENTLY BROKEN CLOUD
COVER OVER SOUTHEASTERN ARIZONA WITH CLEAR TO PARTLY CLOUDY SKIES
OVER NORTHERN ARIZONA. THE CURRENT FORECAST LOOKS GOOD AND NO
UPDATES ARE PLANNED AT THIS TIME.
PREVIOUS DISCUSSION 401 AM
SATELLITE IMAGERY THIS MORNING IS
SHOWING THE UPPER LOW CENTERED OVER CENTRAL BAJA CALIFORNIA. BROKEN
OF MID AND HIGH LEVEL CLOUDS ASSOCIATED WITH THE LOW ARE COVERING
AREAS EAST OF A LINE FROM THE FOUR CORNERS THROUGH YUMA. AREAS WEST
OF THIS LINE ARE UNDER A DEFORMATION AXIS AND ARE MOSTLY CLEAR.
FOR TODAY THROUGH WEDNESDAY...MODELS CONTINUE WITH THE SAME
TUNES...MOVE THE BAJA LOW AND DEFORMATION AXIS EASTWARD
TODAY...WESTERLY FLOW ALOFT ON SUNDAY...A TRANSITORY RIDGE ACROSS
THE DESERT SOUTHWEST MONDAY AND TUESDAY...AND THEN SOUTHWEST FLOW
ALOFT WEDNESDAY AS A TROUGH OF LOW PRESSURE MOVES DOWN THE WEST
COAST. CHANGES TO THE FORECAST PACKAGE WERE TO REDUCE OPAQUE SKY
COVER TONIGHT THROUGH TUESDAY TO SHOW MORE MOSTLY SUNNY MOSTLY
CLEAR...AND TO COOL WEDNESDAY MORNINGS LOW TEMPERATURES 5 TO 10
DEGREES ACROSS THE NORTHLAND PER RECENT MEX MOS FORECASTS.
OTHERWISE THE RUN OF ABOVE NORMAL MAX TEMPERATURES WILL PERSIST.
ASIDE FROM THE BROKEN CLOUD COVER ACROSS EASTERN AZ TODAY...PERIODS
OF HIGH LEVEL CIRRUS WILL CONTINUE. SOUTHWEST WINDS SHOULD TURN
BREEZY WEDNESDAY AFTERNOON.
THURSDAY AND FRIDAY...THE LONG RANGE MODELS FROM 00Z WANT TO PUSH A
COLD FRONT INTO NORTHWESTERN ARIZONA THURSDAY AND ACROSS THE CWA
THURSDAY NIGHT. THERE ARE DIFFERENCES THOUGH #1) IN JUST HOW COLD
THOUGH... WITH THE OPERATIONAL GFS BEING WARMER THAN THE EC AND GFS
ENSEMBLES AND #2) THE EC IS SHOWING A VERY MUCH COLDER CLOSED LOW
OVER THE GREAT BASIN FRIDAY. MODEL MOISTURE WITH THE FRONT HAS BEEN
TRENDING DRIER AND POPS WERE CUT BY 10 PERCENT FOR THIS PERIOD. MAX
TEMPS SHOW A COOLING TREND...AND FRIDAYS MAY NEED TO GO LOWER SHOULD
THE EC VERIFY.
AVIATION...FOR THE 18Z PACKAGE
VFR CONDITIONS WILL CONTINUE UNDER
VARIABLE HIGH LEVEL CLOUDS OVER THE NEXT 24 HOURS. SOUTHWEST WINDS
AT 10-15 KT WILL DEVELOP AT MOST LOCATIONS THROUGH 01Z/SUN. LOCAL
SMOKE FROM BURNS MAY REDUCE THE VISIBILITY DOWN TO 1/2 MILE AT
TIMES LATE NIGHT THROUGH EARLY MORNING. AVIATION DISCUSSION NOT
UPDATED FOR AMENDMENTS.
FGZ WATCHES/WARNINGS/ADVISORIES
NONE.
PUBLIC.................JVC
AVIATION...............MAS
VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER INFORMATION.
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