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000
FXUS65 KPSR 230421
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
921 PM MST MON SEP 22 2014

.SYNOPSIS...
SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE
HIGHER MOUNTAINS OF SOUTH-CENTRAL ARIZONA THROUGH THURSDAY.
TEMPERATURES WILL TREND UPWARD A FEW DEGREES BY WEDNESDAY. AN
APPROACHING PACIFIC WEATHER SYSTEM LIKELY AFFECTING THE DESERT
SOUTHWEST ON FRIDAY THROUGH SUNDAY WILL LEAD TO A RETURN OF STORM
CHANCES ALONG WITH COOLER TEMPERATURES.

&&

.DISCUSSION...
RADAR SCOPES WENT QUIET FAIRLY EARLY THIS EVENING WITH THE ONLY
STORM ACTIVITY IN OUR FORECAST TODAY OVER THE SOUTHERN GILA COUNTY
HIGHER TERRAIN. WESTERLY WINDS THROUGH MUCH OF THE ATMO COLUMN
PUSHED STORMS TO THE EAST AND TOWARDS A MORE FAVORABLE MOISTURE
SURFACE ALONG THE AZ/NM BORDER. AFTERNOON MIXING DROPPED DEWPOINTS
READINGS INTO THE 30S AND 40S ACROSS SOUTHEAST CA AND WESTERN
AZ...WITH STILL RICH UPPER 50 AND 60 DEGREE READINGS SCATTERED
THROUGHOUT POCKETS OF THE PHX METRO AND SOLIDLY POINTS EAST. WITH
CONTINUED DRY AIR INTRUSION FROM THE WEST AS SEEN FROM WATER VAPOR
IMAGERY AND RAPIDLY CLEARING SKIES...ZEROED OUT THE POP FORECAST FOR
THE REST OF THE EVENING. NO OTHER UPDATES NEEDED THIS
EVENING...DISCUSSION BELOW STILL APPLIES FOR MIDWEEK AND BEYOND.

&&

.PREVIOUS DISCUSSION...
THROUGH THURSDAY...WIDELY SCATTERED THUNDERSTORM ACTIVITY HAS POPPED
UP THIS AFTERNOON ACROSS PORTIONS OF EASTERN ARIZONA...SOME ACTIVITY
EXTENDING INTO WESTERN COLORADO AND FORMING ALONG THE TRAILING AXIS
OF THE UPPER LEVEL TROUGH CURRENTLY MOVING EAST ACROSS THE NORTHERN
TIER OF THE CONUS. THUNDERSTORM ACTIVITY WILL REMAIN RELEGATED TO
EASTERN ARIZONA THIS AFTERNOON...WITH ONLY SLIGHT CHANCES OF
PRECIPITATION OVER SOUTHERN GILA COUNTY INTO THE EVENING HOURS. WITH
THE DRIER WESTERLY FLOW IN PLACE OVER SOUTHEAST CA AND MOST OF
ARIZONA...PRECIPITATION CHANCES WILL BE NIL FOR THE LOWER DESERTS
UNTIL THE END OF THE WEEK.

MODELS CONTINUE TO SUGGEST THAT THE UPPER LEVEL RIDGE AXIS WILL
ESTABLISH AND REMAIN OVER THE INTERMOUNTAIN WEST THROUGH AT LEAST
WEDNESDAY...ALONG WITH SOME MODEST DRYING OF THE ATMOSPHERE THAT
WILL TAKE PLACE. THE ANTICYCLONIC FLOW WILL SUPPORT A FEW LOW-MID
LEVEL MOISTURE SEEPS FROM TIME TO TIME...RECYCLING MOISTURE UNDER
THE HIGH...JUST ENOUGH MOISTURE TO KEEP A DAILY ROUND OF ISOLATED TO
WIDELY SCATTERED THUNDERSTORMS OVER THE HIGHER TERRAIN OF SOUTH
CENTRAL ARIZONA IN THE FORECAST FOR THE NEXT FEW DAYS. DAYTIME
TEMPERATURES WILL ALSO TREND UPWARD TO AROUND 5-7 DEGREES ABOVE
NORMAL THROUGH MID-WEEK...TOPPING OUT IN THE 104 TO 108 DEGREE RANGE
FOR THE LOWER DESERTS...AS THE RIDGE AMPLIFIES AHEAD OF A LARGE
EASTERN PACIFIC TROUGH DROPPING SOUTH OUT OF THE GULF OF ALASKA.
WEDNESDAY AND THURSDAY WILL LIKELY BE OUR WARMEST DAYS THIS WEEK...
AROUND 105 FOR PHOENIX...AND PROBABLY THE LAST OF THE 100 DEGREE
HEAT AND THE HOT TEMPERATURES UNTIL NEXT YEAR. SAY GOODBYE TO
MONSOON 2014.

FRIDAY THROUGH SUNDAY...GFS AND ECMWF SHOW MORE DISTINCT DIFFERENCES
WITH THE SLOWLY ADVANCING TROUGH. THE GFS IS FASTER WITH THE INLAND
MOVEMENT WHILE THE ECMWF IS DEEPER AND SLOWER. THIS HAS BEEN THE
CASE FOR MULTIPLE RUNS. OF NOTE HOWEVER...THEY BOTH DEPICT DEEPER
TROPICAL MOISTURE BEING PULLED NORTHWARD...ALTHOUGH THE ECMWF IS
MORE GENEROUS. THUS FRIDAY LOOKS TO BE THE BEGINNING OF A WINDOW OF
OPPORTUNITY FOR A MAJORITY OF OUR FORECAST AREA TO HAVE AT LEAST
SOME CHANCE OF SHOWERS/THUNDERSTORMS INTO THE WEEKEND...WITH THE
BEST TIMING FOR PEAK PRECIPITATION SLATED FOR SATURDAY.

BOTH MODELS CONTINUE TO TRACK THE BRUNT OF THE SYSTEM TO OUR NORTH
KEEPING THE JET AXIS JUST TO OUR NORTH. ACCORDINGLY...WE ONLY GET
BRUSHED WITH QG FORCING BUT MAY HAVE SOME UPPER LEVEL DIFFLUENCE TO
WORK WITH IN ADDITION TO CAPE. STRONGER FLOW ALOFT WILL BRING SOME
VERTICAL WIND SHEAR INTO PLAY AS WELL. BOTH THE GFS AND ECMWF HAVE
SUPPORT FROM THEIR RESPECTIVE ENSEMBLES IN TERMS OF HOW THEY HANDLE
THE TROUGH. THE 00Z GFS APPEARS TO HAVE TRENDED SLIGHTLY SLOWER FROM
THE 12Z RUN. STILL A LOT OF UNCERTAINTY WITH HOW THE TROUGH WILL
PLAY OUT AND WHAT THE MOISTURE AND CAPE WILL BE LIKE.
HOWEVER...ENOUGH TO GO ON IN ORDER TO MAKE UPWARD ADJUSTMENTS TO THE
POPS. TEMPS WILL TREND DOWN AS WELL.

&&

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

CLEAR SKIES AND DRY SFC CONDITIONS EXPECTED THROUGH THE TAF PERIOD
WITH DIURNALLY DRIVEN WINDS REMAINING AOB 10KTS. NO WEATHER IMPACTS
TO AVIATION OPERATIONS EXPECTED.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
WESTERLY FLOW ALOFT TO KEEP MOISTURE LEVELS LIMITED ON
THURSDAY...WITH ONLY A SLIGHT CHANCE FOR STORMS OVER THE HIGHER
TERRAIN NORTH AND EAST OF PHOENIX. MOISTURE LEVELS...AND CHANCES FOR
SHOWERS/THUNDERSTORMS TO INCREASE SOMEWHAT ON FRIDAY...THEN
DRAMATICALLY SO ON SATURDAY AND EARLY SUNDAY AS WINDS ALOFT BECOME
MORE SOUTHERLY AHEAD OF A PACIFIC WEATHER SYSTEM THAT WILL BE
APPROACHING THE AREA FROM THE WEST...PULLING TROPICAL MOISTURE BACK
NORTHWARD INTO THE REGION. WIDESPREAD WETTING RAINS...COOLER
TEMPERATURES...AND BREEZY TO WINDY CONDITIONS ARE POSSIBLE FROM
SATURDAY INTO EARLY SUNDAY AS THE 1ST SFC COLD FRONT OF THE EARLY
FALL SEASON MOVES ACROSS THE REGION. MUCH DRIER AIR TO OVERSPREAD
THE REGION FROM WEST TO EAST FROM LATE SUNDAY INTO MONDAY AS HIGH
PRESSURE BUILD INLAND BEHIND THE FRONT. MINIMUM HUMIDITIES ACROSS
THE LOWER DESERTS...WHICH COULD FALL AS LOW AS 15 PERCENT ON
FRIDAY...ARE EXPECTED TO REMAIN MAINLY AOA 25 PERCENT ON SUNDAY AND
MONDAY...BEFORE FALLING BACK DOWN INTO THE 15-25 PERCENT RANGE ON
MONDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

PREVIOUS DISCUSSION...NOLTE
DISCUSSION...MEYERS/AJ
AVIATION....NOLTE
FIRE WEATHER...PERCHA






000
FXUS65 KPSR 230421
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
921 PM MST MON SEP 22 2014

.SYNOPSIS...
SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE
HIGHER MOUNTAINS OF SOUTH-CENTRAL ARIZONA THROUGH THURSDAY.
TEMPERATURES WILL TREND UPWARD A FEW DEGREES BY WEDNESDAY. AN
APPROACHING PACIFIC WEATHER SYSTEM LIKELY AFFECTING THE DESERT
SOUTHWEST ON FRIDAY THROUGH SUNDAY WILL LEAD TO A RETURN OF STORM
CHANCES ALONG WITH COOLER TEMPERATURES.

&&

.DISCUSSION...
RADAR SCOPES WENT QUIET FAIRLY EARLY THIS EVENING WITH THE ONLY
STORM ACTIVITY IN OUR FORECAST TODAY OVER THE SOUTHERN GILA COUNTY
HIGHER TERRAIN. WESTERLY WINDS THROUGH MUCH OF THE ATMO COLUMN
PUSHED STORMS TO THE EAST AND TOWARDS A MORE FAVORABLE MOISTURE
SURFACE ALONG THE AZ/NM BORDER. AFTERNOON MIXING DROPPED DEWPOINTS
READINGS INTO THE 30S AND 40S ACROSS SOUTHEAST CA AND WESTERN
AZ...WITH STILL RICH UPPER 50 AND 60 DEGREE READINGS SCATTERED
THROUGHOUT POCKETS OF THE PHX METRO AND SOLIDLY POINTS EAST. WITH
CONTINUED DRY AIR INTRUSION FROM THE WEST AS SEEN FROM WATER VAPOR
IMAGERY AND RAPIDLY CLEARING SKIES...ZEROED OUT THE POP FORECAST FOR
THE REST OF THE EVENING. NO OTHER UPDATES NEEDED THIS
EVENING...DISCUSSION BELOW STILL APPLIES FOR MIDWEEK AND BEYOND.

&&

.PREVIOUS DISCUSSION...
THROUGH THURSDAY...WIDELY SCATTERED THUNDERSTORM ACTIVITY HAS POPPED
UP THIS AFTERNOON ACROSS PORTIONS OF EASTERN ARIZONA...SOME ACTIVITY
EXTENDING INTO WESTERN COLORADO AND FORMING ALONG THE TRAILING AXIS
OF THE UPPER LEVEL TROUGH CURRENTLY MOVING EAST ACROSS THE NORTHERN
TIER OF THE CONUS. THUNDERSTORM ACTIVITY WILL REMAIN RELEGATED TO
EASTERN ARIZONA THIS AFTERNOON...WITH ONLY SLIGHT CHANCES OF
PRECIPITATION OVER SOUTHERN GILA COUNTY INTO THE EVENING HOURS. WITH
THE DRIER WESTERLY FLOW IN PLACE OVER SOUTHEAST CA AND MOST OF
ARIZONA...PRECIPITATION CHANCES WILL BE NIL FOR THE LOWER DESERTS
UNTIL THE END OF THE WEEK.

MODELS CONTINUE TO SUGGEST THAT THE UPPER LEVEL RIDGE AXIS WILL
ESTABLISH AND REMAIN OVER THE INTERMOUNTAIN WEST THROUGH AT LEAST
WEDNESDAY...ALONG WITH SOME MODEST DRYING OF THE ATMOSPHERE THAT
WILL TAKE PLACE. THE ANTICYCLONIC FLOW WILL SUPPORT A FEW LOW-MID
LEVEL MOISTURE SEEPS FROM TIME TO TIME...RECYCLING MOISTURE UNDER
THE HIGH...JUST ENOUGH MOISTURE TO KEEP A DAILY ROUND OF ISOLATED TO
WIDELY SCATTERED THUNDERSTORMS OVER THE HIGHER TERRAIN OF SOUTH
CENTRAL ARIZONA IN THE FORECAST FOR THE NEXT FEW DAYS. DAYTIME
TEMPERATURES WILL ALSO TREND UPWARD TO AROUND 5-7 DEGREES ABOVE
NORMAL THROUGH MID-WEEK...TOPPING OUT IN THE 104 TO 108 DEGREE RANGE
FOR THE LOWER DESERTS...AS THE RIDGE AMPLIFIES AHEAD OF A LARGE
EASTERN PACIFIC TROUGH DROPPING SOUTH OUT OF THE GULF OF ALASKA.
WEDNESDAY AND THURSDAY WILL LIKELY BE OUR WARMEST DAYS THIS WEEK...
AROUND 105 FOR PHOENIX...AND PROBABLY THE LAST OF THE 100 DEGREE
HEAT AND THE HOT TEMPERATURES UNTIL NEXT YEAR. SAY GOODBYE TO
MONSOON 2014.

FRIDAY THROUGH SUNDAY...GFS AND ECMWF SHOW MORE DISTINCT DIFFERENCES
WITH THE SLOWLY ADVANCING TROUGH. THE GFS IS FASTER WITH THE INLAND
MOVEMENT WHILE THE ECMWF IS DEEPER AND SLOWER. THIS HAS BEEN THE
CASE FOR MULTIPLE RUNS. OF NOTE HOWEVER...THEY BOTH DEPICT DEEPER
TROPICAL MOISTURE BEING PULLED NORTHWARD...ALTHOUGH THE ECMWF IS
MORE GENEROUS. THUS FRIDAY LOOKS TO BE THE BEGINNING OF A WINDOW OF
OPPORTUNITY FOR A MAJORITY OF OUR FORECAST AREA TO HAVE AT LEAST
SOME CHANCE OF SHOWERS/THUNDERSTORMS INTO THE WEEKEND...WITH THE
BEST TIMING FOR PEAK PRECIPITATION SLATED FOR SATURDAY.

BOTH MODELS CONTINUE TO TRACK THE BRUNT OF THE SYSTEM TO OUR NORTH
KEEPING THE JET AXIS JUST TO OUR NORTH. ACCORDINGLY...WE ONLY GET
BRUSHED WITH QG FORCING BUT MAY HAVE SOME UPPER LEVEL DIFFLUENCE TO
WORK WITH IN ADDITION TO CAPE. STRONGER FLOW ALOFT WILL BRING SOME
VERTICAL WIND SHEAR INTO PLAY AS WELL. BOTH THE GFS AND ECMWF HAVE
SUPPORT FROM THEIR RESPECTIVE ENSEMBLES IN TERMS OF HOW THEY HANDLE
THE TROUGH. THE 00Z GFS APPEARS TO HAVE TRENDED SLIGHTLY SLOWER FROM
THE 12Z RUN. STILL A LOT OF UNCERTAINTY WITH HOW THE TROUGH WILL
PLAY OUT AND WHAT THE MOISTURE AND CAPE WILL BE LIKE.
HOWEVER...ENOUGH TO GO ON IN ORDER TO MAKE UPWARD ADJUSTMENTS TO THE
POPS. TEMPS WILL TREND DOWN AS WELL.

&&

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

CLEAR SKIES AND DRY SFC CONDITIONS EXPECTED THROUGH THE TAF PERIOD
WITH DIURNALLY DRIVEN WINDS REMAINING AOB 10KTS. NO WEATHER IMPACTS
TO AVIATION OPERATIONS EXPECTED.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
WESTERLY FLOW ALOFT TO KEEP MOISTURE LEVELS LIMITED ON
THURSDAY...WITH ONLY A SLIGHT CHANCE FOR STORMS OVER THE HIGHER
TERRAIN NORTH AND EAST OF PHOENIX. MOISTURE LEVELS...AND CHANCES FOR
SHOWERS/THUNDERSTORMS TO INCREASE SOMEWHAT ON FRIDAY...THEN
DRAMATICALLY SO ON SATURDAY AND EARLY SUNDAY AS WINDS ALOFT BECOME
MORE SOUTHERLY AHEAD OF A PACIFIC WEATHER SYSTEM THAT WILL BE
APPROACHING THE AREA FROM THE WEST...PULLING TROPICAL MOISTURE BACK
NORTHWARD INTO THE REGION. WIDESPREAD WETTING RAINS...COOLER
TEMPERATURES...AND BREEZY TO WINDY CONDITIONS ARE POSSIBLE FROM
SATURDAY INTO EARLY SUNDAY AS THE 1ST SFC COLD FRONT OF THE EARLY
FALL SEASON MOVES ACROSS THE REGION. MUCH DRIER AIR TO OVERSPREAD
THE REGION FROM WEST TO EAST FROM LATE SUNDAY INTO MONDAY AS HIGH
PRESSURE BUILD INLAND BEHIND THE FRONT. MINIMUM HUMIDITIES ACROSS
THE LOWER DESERTS...WHICH COULD FALL AS LOW AS 15 PERCENT ON
FRIDAY...ARE EXPECTED TO REMAIN MAINLY AOA 25 PERCENT ON SUNDAY AND
MONDAY...BEFORE FALLING BACK DOWN INTO THE 15-25 PERCENT RANGE ON
MONDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

PREVIOUS DISCUSSION...NOLTE
DISCUSSION...MEYERS/AJ
AVIATION....NOLTE
FIRE WEATHER...PERCHA







000
FXUS65 KPSR 222141
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
240 PM MST MON SEP 22 2014

.SYNOPSIS...
SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE
HIGHER MOUNTAINS OF SOUTH-CENTRAL ARIZONA THROUGH THURSDAY.
TEMPERATURES WILL TREND UPWARD A FEW DEGREES BY WEDNESDAY. AN
APPROACHING PACIFIC WEATHER SYSTEM LIKELY AFFECTING THE DESERT
SOUTHWEST ON FRIDAY THROUGH SUNDAY WILL LEAD TO A RETURN OF STORM
CHANCES ALONG WITH COOLER TEMPERATURES.

&&

.DISCUSSION...
TONIGHT THROUGH THURSDAY...WIDELY SCATTERED THUNDERSTORM ACTIVITY
HAS POPPED UP THIS AFTERNOON ACROSS PORTIONS OF EASTERN ARIZONA...
SOME ACTIVITY EXTENDING INTO WESTERN COLORADO AND FORMING ALONG THE
TRAILING AXIS OF THE UPPER LEVEL TROUGH CURRENTLY MOVING EAST ACROSS
THE NORTHERN TIER OF THE CONUS. THUNDERSTORM ACTIVITY WILL REMAIN
RELEGATED TO EASTERN ARIZONA THIS AFTERNOON...WITH ONLY SLIGHT
CHANCES OF PRECIPITATION OVER SOUTHERN GILA COUNTY INTO THE EVENING
HOURS. WITH THE DRIER WESTERLY FLOW IN PLACE OVER SOUTHEAST CA AND
MOST OF ARIZONA...PRECIPITATION CHANCES WILL BE NIL FOR THE LOWER
DESERTS UNTIL THE END OF THE WEEK.

MODELS CONTINUE TO SUGGEST THAT THE UPPER LEVEL RIDGE AXIS WILL
ESTABLISH AND REMAIN OVER THE INTERMOUNTAIN WEST THROUGH AT LEAST
WEDNESDAY...ALONG WITH SOME MODEST DRYING OF THE ATMOSPHERE THAT
WILL TAKE PLACE. THE ANTICYCLONIC FLOW WILL SUPPORT A FEW LOW-MID
LEVEL MOISTURE SEEPS FROM TIME TO TIME...RECYCLING MOISTURE UNDER
THE HIGH...JUST ENOUGH MOISTURE TO KEEP A DAILY ROUND OF ISOLATED TO
WIDELY SCATTERED THUNDERSTORMS OVER THE HIGHER TERRAIN OF SOUTH
CENTRAL ARIZONA IN THE FORECAST FOR THE NEXT FEW DAYS. DAYTIME
TEMPERATURES WILL ALSO TREND UPWARD TO AROUND 5-7 DEGREES ABOVE
NORMAL THROUGH MID-WEEK...TOPPING OUT IN THE 104 TO 108 DEGREE RANGE
FOR THE LOWER DESERTS...AS THE RIDGE AMPLIFIES AHEAD OF A LARGE
EASTERN PACIFIC TROUGH DROPPING SOUTH OUT OF THE GULF OF ALASKA.
WEDNESDAY AND THURSDAY WILL LIKELY BE OUR WARMEST DAYS THIS WEEK...
AROUND 105 FOR PHOENIX...AND PROBABLY THE LAST OF THE 100 DEGREE
HEAT AND THE HOT TEMPERATURES UNTIL NEXT YEAR. SAY GOODBYE TO
MONSOON 2014.

FRIDAY THROUGH SUNDAY...GFS AND ECMWF SHOW MORE DISTINCT DIFFERENCES
WITH THE SLOWLY ADVANCING TROUGH. THE GFS IS FASTER WITH THE INLAND
MOVEMENT WHILE THE ECMWF IS DEEPER AND SLOWER. THIS HAS BEEN THE
CASE FOR MULTIPLE RUNS. OF NOTE HOWEVER...THEY BOTH DEPICT DEEPER
TROPICAL MOISTURE BEING PULLED NORTHWARD...ALTHOUGH THE ECMWF IS
MORE GENEROUS. THUS FRIDAY LOOKS TO BE THE BEGINNING OF A WINDOW OF
OPPORTUNITY FOR A MAJORITY OF OUR FORECAST AREA TO HAVE AT LEAST
SOME CHANCE OF SHOWERS/THUNDERSTORMS INTO THE WEEKEND...WITH THE
BEST TIMING FOR PEAK PRECIPITATION SLATED FOR SATURDAY.

BOTH MODELS CONTINUE TO TRACK THE BRUNT OF THE SYSTEM TO OUR NORTH
KEEPING THE JET AXIS JUST TO OUR NORTH. ACCORDINGLY...WE ONLY GET
BRUSHED WITH QG FORCING BUT MAY HAVE SOME UPPER LEVEL DIFFLUENCE TO
WORK WITH IN ADDITION TO CAPE. STRONGER FLOW ALOFT WILL BRING SOME
VERTICAL WIND SHEAR INTO PLAY AS WELL. BOTH THE GFS AND ECMWF HAVE
SUPPORT FROM THEIR RESPECTIVE ENSEMBLES IN TERMS OF HOW THEY HANDLE
THE TROUGH. THE 00Z GFS APPEARS TO HAVE TRENDED SLIGHTLY SLOWER FROM
THE 12Z RUN. STILL A LOT OF UNCERTAINTY WITH HOW THE TROUGH WILL
PLAY OUT AND WHAT THE MOISTURE AND CAPE WILL BE LIKE.
HOWEVER...ENOUGH TO GO ON IN ORDER TO MAKE UPWARD ADJUSTMENTS TO THE
POPS. TEMPS WILL TREND DOWN AS WELL.

&&

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

DRY CONDITIONS AND CLEAR TO MOSTLY CLEAR SKIES TO CONTINUE THROUGH
THE TAF PERIOD. WINDS TO FOLLOW TYPICAL DIURNAL PATTERNS...WITH THE
TYPICAL AFTERNOON BREEZES ACROSS THE PHOENIX AREA REMAINING A LITTLE
LIGHTER THEN USUAL.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
WESTERLY FLOW ALOFT TO KEEP MOISTURE LEVELS LIMITED ON
THURSDAY...WITH ONLY A SLIGHT CHANCE FOR STORMS OVER THE HIGHER
TERRAIN NORTH AND EAST OF PHOENIX. MOISTURE LEVELS...AND CHANCES FOR
SHOWERS/THUNDERSTORMS TO INCREASE SOMEWHAT ON FRIDAY...THEN
DRAMATICALLY SO ON SATURDAY AND EARLY SUNDAY AS WINDS ALOFT BECOME
MORE SOUTHERLY AHEAD OF A PACIFIC WEATHER SYSTEM THAT WILL BE
APPROACHING THE AREA FROM THE WEST...PULLING TROPICAL MOISTURE BACK
NORTHWARD INTO THE REGION. WIDESPREAD WETTING RAINS...COOLER
TEMPERATURES...AND BREEZY TO WINDY CONDITIONS ARE POSSIBLE FROM
SATURDAY INTO EARLY SUNDAY AS THE 1ST SFC COLD FRONT OF THE EARLY
FALL SEASON MOVES ACROSS THE REGION. MUCH DRIER AIR TO OVERSPREAD
THE REGION FROM WEST TO EAST FROM LATE SUNDAY INTO MONDAY AS HIGH
PRESSURE BUILD INLAND BEHIND THE FRONT. MINIMUM HUMIDITIES ACROSS
THE LOWER DESERTS...WHICH COULD FALL AS LOW AS 15 PERCENT ON
FRIDAY...ARE EXPECTED TO REMAIN MAINLY AOA 25 PERCENT ON SUNDAY AND
MONDAY...BEFORE FALLING BACK DOWN INTO THE 15-25 PERCENT RANGE ON
MONDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

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







000
FXUS65 KPSR 222141
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
240 PM MST MON SEP 22 2014

.SYNOPSIS...
SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE
HIGHER MOUNTAINS OF SOUTH-CENTRAL ARIZONA THROUGH THURSDAY.
TEMPERATURES WILL TREND UPWARD A FEW DEGREES BY WEDNESDAY. AN
APPROACHING PACIFIC WEATHER SYSTEM LIKELY AFFECTING THE DESERT
SOUTHWEST ON FRIDAY THROUGH SUNDAY WILL LEAD TO A RETURN OF STORM
CHANCES ALONG WITH COOLER TEMPERATURES.

&&

.DISCUSSION...
TONIGHT THROUGH THURSDAY...WIDELY SCATTERED THUNDERSTORM ACTIVITY
HAS POPPED UP THIS AFTERNOON ACROSS PORTIONS OF EASTERN ARIZONA...
SOME ACTIVITY EXTENDING INTO WESTERN COLORADO AND FORMING ALONG THE
TRAILING AXIS OF THE UPPER LEVEL TROUGH CURRENTLY MOVING EAST ACROSS
THE NORTHERN TIER OF THE CONUS. THUNDERSTORM ACTIVITY WILL REMAIN
RELEGATED TO EASTERN ARIZONA THIS AFTERNOON...WITH ONLY SLIGHT
CHANCES OF PRECIPITATION OVER SOUTHERN GILA COUNTY INTO THE EVENING
HOURS. WITH THE DRIER WESTERLY FLOW IN PLACE OVER SOUTHEAST CA AND
MOST OF ARIZONA...PRECIPITATION CHANCES WILL BE NIL FOR THE LOWER
DESERTS UNTIL THE END OF THE WEEK.

MODELS CONTINUE TO SUGGEST THAT THE UPPER LEVEL RIDGE AXIS WILL
ESTABLISH AND REMAIN OVER THE INTERMOUNTAIN WEST THROUGH AT LEAST
WEDNESDAY...ALONG WITH SOME MODEST DRYING OF THE ATMOSPHERE THAT
WILL TAKE PLACE. THE ANTICYCLONIC FLOW WILL SUPPORT A FEW LOW-MID
LEVEL MOISTURE SEEPS FROM TIME TO TIME...RECYCLING MOISTURE UNDER
THE HIGH...JUST ENOUGH MOISTURE TO KEEP A DAILY ROUND OF ISOLATED TO
WIDELY SCATTERED THUNDERSTORMS OVER THE HIGHER TERRAIN OF SOUTH
CENTRAL ARIZONA IN THE FORECAST FOR THE NEXT FEW DAYS. DAYTIME
TEMPERATURES WILL ALSO TREND UPWARD TO AROUND 5-7 DEGREES ABOVE
NORMAL THROUGH MID-WEEK...TOPPING OUT IN THE 104 TO 108 DEGREE RANGE
FOR THE LOWER DESERTS...AS THE RIDGE AMPLIFIES AHEAD OF A LARGE
EASTERN PACIFIC TROUGH DROPPING SOUTH OUT OF THE GULF OF ALASKA.
WEDNESDAY AND THURSDAY WILL LIKELY BE OUR WARMEST DAYS THIS WEEK...
AROUND 105 FOR PHOENIX...AND PROBABLY THE LAST OF THE 100 DEGREE
HEAT AND THE HOT TEMPERATURES UNTIL NEXT YEAR. SAY GOODBYE TO
MONSOON 2014.

FRIDAY THROUGH SUNDAY...GFS AND ECMWF SHOW MORE DISTINCT DIFFERENCES
WITH THE SLOWLY ADVANCING TROUGH. THE GFS IS FASTER WITH THE INLAND
MOVEMENT WHILE THE ECMWF IS DEEPER AND SLOWER. THIS HAS BEEN THE
CASE FOR MULTIPLE RUNS. OF NOTE HOWEVER...THEY BOTH DEPICT DEEPER
TROPICAL MOISTURE BEING PULLED NORTHWARD...ALTHOUGH THE ECMWF IS
MORE GENEROUS. THUS FRIDAY LOOKS TO BE THE BEGINNING OF A WINDOW OF
OPPORTUNITY FOR A MAJORITY OF OUR FORECAST AREA TO HAVE AT LEAST
SOME CHANCE OF SHOWERS/THUNDERSTORMS INTO THE WEEKEND...WITH THE
BEST TIMING FOR PEAK PRECIPITATION SLATED FOR SATURDAY.

BOTH MODELS CONTINUE TO TRACK THE BRUNT OF THE SYSTEM TO OUR NORTH
KEEPING THE JET AXIS JUST TO OUR NORTH. ACCORDINGLY...WE ONLY GET
BRUSHED WITH QG FORCING BUT MAY HAVE SOME UPPER LEVEL DIFFLUENCE TO
WORK WITH IN ADDITION TO CAPE. STRONGER FLOW ALOFT WILL BRING SOME
VERTICAL WIND SHEAR INTO PLAY AS WELL. BOTH THE GFS AND ECMWF HAVE
SUPPORT FROM THEIR RESPECTIVE ENSEMBLES IN TERMS OF HOW THEY HANDLE
THE TROUGH. THE 00Z GFS APPEARS TO HAVE TRENDED SLIGHTLY SLOWER FROM
THE 12Z RUN. STILL A LOT OF UNCERTAINTY WITH HOW THE TROUGH WILL
PLAY OUT AND WHAT THE MOISTURE AND CAPE WILL BE LIKE.
HOWEVER...ENOUGH TO GO ON IN ORDER TO MAKE UPWARD ADJUSTMENTS TO THE
POPS. TEMPS WILL TREND DOWN AS WELL.

&&

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

DRY CONDITIONS AND CLEAR TO MOSTLY CLEAR SKIES TO CONTINUE THROUGH
THE TAF PERIOD. WINDS TO FOLLOW TYPICAL DIURNAL PATTERNS...WITH THE
TYPICAL AFTERNOON BREEZES ACROSS THE PHOENIX AREA REMAINING A LITTLE
LIGHTER THEN USUAL.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
WESTERLY FLOW ALOFT TO KEEP MOISTURE LEVELS LIMITED ON
THURSDAY...WITH ONLY A SLIGHT CHANCE FOR STORMS OVER THE HIGHER
TERRAIN NORTH AND EAST OF PHOENIX. MOISTURE LEVELS...AND CHANCES FOR
SHOWERS/THUNDERSTORMS TO INCREASE SOMEWHAT ON FRIDAY...THEN
DRAMATICALLY SO ON SATURDAY AND EARLY SUNDAY AS WINDS ALOFT BECOME
MORE SOUTHERLY AHEAD OF A PACIFIC WEATHER SYSTEM THAT WILL BE
APPROACHING THE AREA FROM THE WEST...PULLING TROPICAL MOISTURE BACK
NORTHWARD INTO THE REGION. WIDESPREAD WETTING RAINS...COOLER
TEMPERATURES...AND BREEZY TO WINDY CONDITIONS ARE POSSIBLE FROM
SATURDAY INTO EARLY SUNDAY AS THE 1ST SFC COLD FRONT OF THE EARLY
FALL SEASON MOVES ACROSS THE REGION. MUCH DRIER AIR TO OVERSPREAD
THE REGION FROM WEST TO EAST FROM LATE SUNDAY INTO MONDAY AS HIGH
PRESSURE BUILD INLAND BEHIND THE FRONT. MINIMUM HUMIDITIES ACROSS
THE LOWER DESERTS...WHICH COULD FALL AS LOW AS 15 PERCENT ON
FRIDAY...ARE EXPECTED TO REMAIN MAINLY AOA 25 PERCENT ON SUNDAY AND
MONDAY...BEFORE FALLING BACK DOWN INTO THE 15-25 PERCENT RANGE ON
MONDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

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






000
FXUS65 KPSR 222017
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
955 AM MST MON SEP 22 2014

.SYNOPSIS...
SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE
HIGHER MOUNTAINS OF SOUTH-CENTRAL ARIZONA THROUGH THURSDAY.
TEMPERATURES WILL TREND UPWARD A FEW DEGREES BY WEDNESDAY. AN
APPROACHING PACIFIC WEATHER SYSTEM LIKELY AFFECTING THE DESERT
SOUTHWEST ON FRIDAY THROUGH SUNDAY WILL LEAD TO A RETURN OF STORM
CHANCES ALONG WITH COOLER TEMPERATURES.

&&

.DISCUSSION...
A GOOD SWATH OF MID LEVEL CLOUDINESS HANGING OVER SOUTH-CENTRAL
ARIZONA THIS MORNING...WITH EVEN SOME LINGERING CONVECTION NEAR THE
NEW MEXICO BORDER. THIS CLOUD COVER WILL THIN OUT AS MORNING
PROGRESSES...BUT VARYING AMOUNTS OF PRECIPITABLE WATER WILL CONTINUE
TO HANG ON OVER THE REGION. PER THE KTWC 12 SOUNDING AND REGIONAL
UPPER AIR PLOTS...THIS BEST MOISTURE BOUNDARY/GRADIENT IS SET UP
OVER THE EASTERN HALF OF ARIZONA...WITH A DENSE MIXING RATIO
GRADIENT OF 10-13G/KG ALONG THE AZ-NM BORDER. MODELS SUGGEST THAT
THE UPPER LEVEL RIDGE AXIS WILL ESTABLISH AND REMAIN OVER THE
INTERMOUNTAIN WEST THROUGH AT LEAST WEDNESDAY...WITH LITTLE
ADDITIONAL DRYING OF THE ATMOSPHERE THAT WILL TAKE PLACE. THE
ANTICYCLONIC FLOW WILL BE ABLE TO IMPORT SOME LOW AND MID LEVEL
MOISTURE FROM TIME TO TIME...AND THIS WILL BE ENOUGH TO SUPPORT A
DAILY ROUND OF ISOLATED/WIDELY SCATTERED THUNDERSTORMS OVER THE
HIGHER TERRAIN WELL EAST OF PHOENIX. AS SUCH...WILL CONTINUE WITH
SLIGHT CHANCE POPS FOR ONLY OUR FAR EASTERN ZONES...KEEPING ALL
OTHER AREAS OF SOUTHWEST AZ AND SOUTHEAST CA DRY THROUGH THURSDAY.
DAYTIME TEMPERATURES WILL ALSO NUDGE UPWARD A FEW DEGREES ABOVE
NORMAL THROUGH MID-WEEK...TOPPING OUT IN THE 104 TO 108 DEGREE RANGE
FOR THE LOWER DESERTS. MADE A FEW MINOR ADJUSTMENTS TO THE NEAR TERM
DIGITAL FORECAST TO BETTER REFLECT CURRENT SATELLITE AND SURFACE OB
TRENDS. PREVIOUS DISCUSSION STILL APPLIES.

PREVIOUS DISCUSSION...
THURSDAY THROUGH SUNDAY...AMPLIFICATION OF THE FLOW PATTERN ON
THURSDAY WILL FORCE A LARGE PACIFIC TROUGH TO SHIFT SOUTHEASTWARD
AND THE RIDGE OVER US TO SHIFT NORTHEASTWARD. IN THE PROCESS...
MOISTURE OVER SOUTHEAST ARIZONA SHIFTS WESTWARD AND SOME DRIER AIR
FROM THE NORTH MIXES IN. STILL ENOUGH MOISTURE ON BALANCE TO
MAINTAIN THE SLIGHT CHANCES OVER ZONE 24 BUT NOT ENOUGH YET TO
INTRODUCE POPS TO THE LOWER DESERTS. BY FRIDAY...GFS AND ECMWF SHOW
MORE DISTINCT DIFFERENCES WITH THE SLOWLY ADVANCING TROUGH. THE GFS
IS FASTER WITH THE INLAND MOVEMENT WHILE THE ECMWF IS DEEPER AND
SLOWER. THIS HAS BEEN THE CASE FOR MULTIPLE RUNS. OF NOTE HOWEVER...
THEY BOTH DEPICT DEEPER MOISTURE BEING PULLED NORTHWARD THOUGH THE
ECMWF IS MORE GENEROUS...AS IS OFTEN THE CASE. THUS FRIDAY LOOKS TO
BE THE BEGINNING OF A WINDOW OF OPPORTUNITY FOR A MAJORITY OF OUR
FORECAST AREA TO HAVE AT LEAST SOME CHANCE SHOWERS/THUNDERSTORMS.
BECAUSE THE GFS IS FASTER AND NOT AS DEEP WITH THE LOW/TROUGH...IT
DEPICTS A SMALLER WINDOW OF OPPORTUNITY... ENDING SUNDAY MORNING
OVER OUR EASTERNMOST AREAS...AND KEEPS QPF PRETTY MUCH EAST OF THE
LOWER COLORADO RIVER VALLEY. THE ECMWF DEPICTS QPF INTO SOUTHEAST
CALIFORNIA AND ENDS IT SUNDAY NIGHT. BOTH TRACK THE BRUNT OF THE
SYSTEM TO OUR NORTH KEEPING THE JET AXIS JUST TO OUR NORTH.
ACCORDINGLY...WE ONLY GET BRUSHED WITH QG FORCING BUT MAY HAVE SOME
UPPER LEVEL DIFFLUENCE TO WORK WITH IN ADDITION TO CAPE. STRONGER
FLOW ALOFT WILL BRING SOME VERTICAL WIND SHEAR INTO PLAY AS WELL.
BOTH THE GFS AND ECMWF HAVE SUPPORT FROM THEIR RESPECTIVE ENSEMBLES
IN TERMS OF HOW THEY HANDLE THE TROUGH. THE 00Z GFS APPEARS TO HAVE
TRENDED SLIGHTLY SLOWER FROM THE 12Z RUN. STILL A LOT OF UNCERTAINTY
WITH HOW THE TROUGH WILL PLAY OUT AND WHAT THE MOISTURE AND CAPE
WILL BE LIKE. HOWEVER...ENOUGH TO GO ON IN ORDER TO MAKE UPWARD
ADJUSTMENTS TO THE POPS. TEMPS WILL TREND DOWN AS WELL.


&&

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

DRY CONDITIONS AND CLEAR TO MOSTLY CLEAR SKIES TO CONTINUE THROUGH
THE TAF PERIOD. WINDS TO FOLLOW TYPICAL DIURNAL PATTERNS...WITH THE
TYPICAL AFTERNOON BREEZES ACROSS THE PHOENIX AREA REMAINING A LITTLE
LIGHTER THEN USUAL.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
WESTERLY FLOW ALOFT TO KEEP MOISTURE LEVELS LIMITED ON
THURSDAY...WITH ONLY A SLIGHT CHANCE FOR STORMS OVER THE HIGHER
TERRAIN NORTH AND EAST OF PHOENIX. MOISTURE LEVELS...AND CHANCES FOR
SHOWERS/THUNDERSTORMS TO INCREASE SOMEWHAT ON FRIDAY...THEN
DRAMATICALLY SO ON SATURDAY AND EARLY SUNDAY AS WINDS ALOFT BECOME
MORE SOUTHERLY AHEAD OF A PACIFIC WEATHER SYSTEM THAT WILL BE
APPROACHING THE AREA FROM THE WEST...PULLING TROPICAL MOISTURE BACK
NORTHWARD INTO THE REGION. WIDESPREAD WETTING RAINS...COOLER
TEMPERATURES...AND BREEZY TO WINDY CONDITIONS ARE POSSIBLE FROM
SATURDAY INTO EARLY SUNDAY AS THE 1ST SFC COLD FRONT OF THE EARLY
FALL SEASON MOVES ACROSS THE REGION. MUCH DRIER AIR TO OVERSPREAD
THE REGION FROM WEST TO EAST FROM LATE SUNDAY INTO MONDAY AS HIGH
PRESSURE BUILD INLAND BEHIND THE FRONT. MINIMUM HUMIDITIES ACROSS
THE LOWER DESERTS...WHICH COULD FALL AS LOW AS 15 PERCENT ON
FRIDAY...ARE EXPECTED TO REMAIN MAINLY AOA 25 PERCENT ON SUNDAY AND
MONDAY...BEFORE FALLING BACK DOWN INTO THE 15-25 PERCENT RANGE ON
MONDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

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







000
FXUS65 KPSR 222017
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
955 AM MST MON SEP 22 2014

.SYNOPSIS...
SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE
HIGHER MOUNTAINS OF SOUTH-CENTRAL ARIZONA THROUGH THURSDAY.
TEMPERATURES WILL TREND UPWARD A FEW DEGREES BY WEDNESDAY. AN
APPROACHING PACIFIC WEATHER SYSTEM LIKELY AFFECTING THE DESERT
SOUTHWEST ON FRIDAY THROUGH SUNDAY WILL LEAD TO A RETURN OF STORM
CHANCES ALONG WITH COOLER TEMPERATURES.

&&

.DISCUSSION...
A GOOD SWATH OF MID LEVEL CLOUDINESS HANGING OVER SOUTH-CENTRAL
ARIZONA THIS MORNING...WITH EVEN SOME LINGERING CONVECTION NEAR THE
NEW MEXICO BORDER. THIS CLOUD COVER WILL THIN OUT AS MORNING
PROGRESSES...BUT VARYING AMOUNTS OF PRECIPITABLE WATER WILL CONTINUE
TO HANG ON OVER THE REGION. PER THE KTWC 12 SOUNDING AND REGIONAL
UPPER AIR PLOTS...THIS BEST MOISTURE BOUNDARY/GRADIENT IS SET UP
OVER THE EASTERN HALF OF ARIZONA...WITH A DENSE MIXING RATIO
GRADIENT OF 10-13G/KG ALONG THE AZ-NM BORDER. MODELS SUGGEST THAT
THE UPPER LEVEL RIDGE AXIS WILL ESTABLISH AND REMAIN OVER THE
INTERMOUNTAIN WEST THROUGH AT LEAST WEDNESDAY...WITH LITTLE
ADDITIONAL DRYING OF THE ATMOSPHERE THAT WILL TAKE PLACE. THE
ANTICYCLONIC FLOW WILL BE ABLE TO IMPORT SOME LOW AND MID LEVEL
MOISTURE FROM TIME TO TIME...AND THIS WILL BE ENOUGH TO SUPPORT A
DAILY ROUND OF ISOLATED/WIDELY SCATTERED THUNDERSTORMS OVER THE
HIGHER TERRAIN WELL EAST OF PHOENIX. AS SUCH...WILL CONTINUE WITH
SLIGHT CHANCE POPS FOR ONLY OUR FAR EASTERN ZONES...KEEPING ALL
OTHER AREAS OF SOUTHWEST AZ AND SOUTHEAST CA DRY THROUGH THURSDAY.
DAYTIME TEMPERATURES WILL ALSO NUDGE UPWARD A FEW DEGREES ABOVE
NORMAL THROUGH MID-WEEK...TOPPING OUT IN THE 104 TO 108 DEGREE RANGE
FOR THE LOWER DESERTS. MADE A FEW MINOR ADJUSTMENTS TO THE NEAR TERM
DIGITAL FORECAST TO BETTER REFLECT CURRENT SATELLITE AND SURFACE OB
TRENDS. PREVIOUS DISCUSSION STILL APPLIES.

PREVIOUS DISCUSSION...
THURSDAY THROUGH SUNDAY...AMPLIFICATION OF THE FLOW PATTERN ON
THURSDAY WILL FORCE A LARGE PACIFIC TROUGH TO SHIFT SOUTHEASTWARD
AND THE RIDGE OVER US TO SHIFT NORTHEASTWARD. IN THE PROCESS...
MOISTURE OVER SOUTHEAST ARIZONA SHIFTS WESTWARD AND SOME DRIER AIR
FROM THE NORTH MIXES IN. STILL ENOUGH MOISTURE ON BALANCE TO
MAINTAIN THE SLIGHT CHANCES OVER ZONE 24 BUT NOT ENOUGH YET TO
INTRODUCE POPS TO THE LOWER DESERTS. BY FRIDAY...GFS AND ECMWF SHOW
MORE DISTINCT DIFFERENCES WITH THE SLOWLY ADVANCING TROUGH. THE GFS
IS FASTER WITH THE INLAND MOVEMENT WHILE THE ECMWF IS DEEPER AND
SLOWER. THIS HAS BEEN THE CASE FOR MULTIPLE RUNS. OF NOTE HOWEVER...
THEY BOTH DEPICT DEEPER MOISTURE BEING PULLED NORTHWARD THOUGH THE
ECMWF IS MORE GENEROUS...AS IS OFTEN THE CASE. THUS FRIDAY LOOKS TO
BE THE BEGINNING OF A WINDOW OF OPPORTUNITY FOR A MAJORITY OF OUR
FORECAST AREA TO HAVE AT LEAST SOME CHANCE SHOWERS/THUNDERSTORMS.
BECAUSE THE GFS IS FASTER AND NOT AS DEEP WITH THE LOW/TROUGH...IT
DEPICTS A SMALLER WINDOW OF OPPORTUNITY... ENDING SUNDAY MORNING
OVER OUR EASTERNMOST AREAS...AND KEEPS QPF PRETTY MUCH EAST OF THE
LOWER COLORADO RIVER VALLEY. THE ECMWF DEPICTS QPF INTO SOUTHEAST
CALIFORNIA AND ENDS IT SUNDAY NIGHT. BOTH TRACK THE BRUNT OF THE
SYSTEM TO OUR NORTH KEEPING THE JET AXIS JUST TO OUR NORTH.
ACCORDINGLY...WE ONLY GET BRUSHED WITH QG FORCING BUT MAY HAVE SOME
UPPER LEVEL DIFFLUENCE TO WORK WITH IN ADDITION TO CAPE. STRONGER
FLOW ALOFT WILL BRING SOME VERTICAL WIND SHEAR INTO PLAY AS WELL.
BOTH THE GFS AND ECMWF HAVE SUPPORT FROM THEIR RESPECTIVE ENSEMBLES
IN TERMS OF HOW THEY HANDLE THE TROUGH. THE 00Z GFS APPEARS TO HAVE
TRENDED SLIGHTLY SLOWER FROM THE 12Z RUN. STILL A LOT OF UNCERTAINTY
WITH HOW THE TROUGH WILL PLAY OUT AND WHAT THE MOISTURE AND CAPE
WILL BE LIKE. HOWEVER...ENOUGH TO GO ON IN ORDER TO MAKE UPWARD
ADJUSTMENTS TO THE POPS. TEMPS WILL TREND DOWN AS WELL.


&&

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

DRY CONDITIONS AND CLEAR TO MOSTLY CLEAR SKIES TO CONTINUE THROUGH
THE TAF PERIOD. WINDS TO FOLLOW TYPICAL DIURNAL PATTERNS...WITH THE
TYPICAL AFTERNOON BREEZES ACROSS THE PHOENIX AREA REMAINING A LITTLE
LIGHTER THEN USUAL.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
WESTERLY FLOW ALOFT TO KEEP MOISTURE LEVELS LIMITED ON
THURSDAY...WITH ONLY A SLIGHT CHANCE FOR STORMS OVER THE HIGHER
TERRAIN NORTH AND EAST OF PHOENIX. MOISTURE LEVELS...AND CHANCES FOR
SHOWERS/THUNDERSTORMS TO INCREASE SOMEWHAT ON FRIDAY...THEN
DRAMATICALLY SO ON SATURDAY AND EARLY SUNDAY AS WINDS ALOFT BECOME
MORE SOUTHERLY AHEAD OF A PACIFIC WEATHER SYSTEM THAT WILL BE
APPROACHING THE AREA FROM THE WEST...PULLING TROPICAL MOISTURE BACK
NORTHWARD INTO THE REGION. WIDESPREAD WETTING RAINS...COOLER
TEMPERATURES...AND BREEZY TO WINDY CONDITIONS ARE POSSIBLE FROM
SATURDAY INTO EARLY SUNDAY AS THE 1ST SFC COLD FRONT OF THE EARLY
FALL SEASON MOVES ACROSS THE REGION. MUCH DRIER AIR TO OVERSPREAD
THE REGION FROM WEST TO EAST FROM LATE SUNDAY INTO MONDAY AS HIGH
PRESSURE BUILD INLAND BEHIND THE FRONT. MINIMUM HUMIDITIES ACROSS
THE LOWER DESERTS...WHICH COULD FALL AS LOW AS 15 PERCENT ON
FRIDAY...ARE EXPECTED TO REMAIN MAINLY AOA 25 PERCENT ON SUNDAY AND
MONDAY...BEFORE FALLING BACK DOWN INTO THE 15-25 PERCENT RANGE ON
MONDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

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






000
FXUS65 KPSR 221658
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
955 AM MST MON SEP 22 2014

.SYNOPSIS...
SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE
HIGHER MOUNTAINS OF SOUTH-CENTRAL ARIZONA THROUGH THURSDAY.
TEMPERATURES WILL TREND UPWARD A FEW DEGREES BY WEDNESDAY. AN
APPROACHING PACIFIC WEATHER SYSTEM LIKELY AFFECTING THE DESERT
SOUTHWEST ON FRIDAY THROUGH SUNDAY WILL LEAD TO A RETURN OF STORM
CHANCES ALONG WITH COOLER TEMPERATURES.

&&

.DISCUSSION...
A GOOD SWATH OF MID LEVEL CLOUDINESS HANGING OVER SOUTH-CENTRAL
ARIZONA THIS MORNING...WITH EVEN SOME LINGERING CONVECTION NEAR THE
NEW MEXICO BORDER. THIS CLOUD COVER WILL THIN OUT AS MORNING
PROGRESSES...BUT VARYING AMOUNTS OF PRECIPITABLE WATER WILL CONTINUE
TO HANG ON OVER THE REGION. PER THE KTWC 12 SOUNDING AND REGIONAL
UPPER AIR PLOTS...THIS BEST MOISTURE BOUNDARY/GRADIENT IS SET UP
OVER THE EASTERN HALF OF ARIZONA...WITH A DENSE MIXING RATIO
GRADIENT OF 10-13G/KG ALONG THE AZ-NM BORDER. MODELS SUGGEST THAT
THE UPPER LEVEL RIDGE AXIS WILL ESTABLISH AND REMAIN OVER THE
INTERMOUNTAIN WEST THROUGH AT LEAST WEDNESDAY...WITH LITTLE
ADDITIONAL DRYING OF THE ATMOSPHERE THAT WILL TAKE PLACE. THE
ANTICYCLONIC FLOW WILL BE ABLE TO IMPORT SOME LOW AND MID LEVEL
MOISTURE FROM TIME TO TIME...AND THIS WILL BE ENOUGH TO SUPPORT A
DAILY ROUND OF ISOLATED/WIDELY SCATTERED THUNDERSTORMS OVER THE
HIGHER TERRAIN WELL EAST OF PHOENIX. AS SUCH...WILL CONTINUE WITH
SLIGHT CHANCE POPS FOR ONLY OUR FAR EASTERN ZONES...KEEPING ALL
OTHER AREAS OF SOUTHWEST AZ AND SOUTHEAST CA DRY THROUGH THURSDAY.
DAYTIME TEMPERATURES WILL ALSO NUDGE UPWARD A FEW DEGREES ABOVE
NORMAL THROUGH MID-WEEK...TOPPING OUT IN THE 104 TO 108 DEGREE RANGE
FOR THE LOWER DESERTS. MADE A FEW MINOR ADJUSTMENTS TO THE NEAR TERM
DIGITAL FORECAST TO BETTER REFLECT CURRENT SATELLITE AND SURFACE OB
TRENDS. PREVIOUS DISCUSSION STILL APPLIES.

PREVIOUS DISCUSSION...
THURSDAY THROUGH SUNDAY...AMPLIFICATION OF THE FLOW PATTERN ON
THURSDAY WILL FORCE A LARGE PACIFIC TROUGH TO SHIFT SOUTHEASTWARD
AND THE RIDGE OVER US TO SHIFT NORTHEASTWARD. IN THE PROCESS...
MOISTURE OVER SOUTHEAST ARIZONA SHIFTS WESTWARD AND SOME DRIER AIR
FROM THE NORTH MIXES IN. STILL ENOUGH MOISTURE ON BALANCE TO
MAINTAIN THE SLIGHT CHANCES OVER ZONE 24 BUT NOT ENOUGH YET TO
INTRODUCE POPS TO THE LOWER DESERTS. BY FRIDAY...GFS AND ECMWF SHOW
MORE DISTINCT DIFFERENCES WITH THE SLOWLY ADVANCING TROUGH. THE GFS
IS FASTER WITH THE INLAND MOVEMENT WHILE THE ECMWF IS DEEPER AND
SLOWER. THIS HAS BEEN THE CASE FOR MULTIPLE RUNS. OF NOTE HOWEVER...
THEY BOTH DEPICT DEEPER MOISTURE BEING PULLED NORTHWARD THOUGH THE
ECMWF IS MORE GENEROUS...AS IS OFTEN THE CASE. THUS FRIDAY LOOKS TO
BE THE BEGINNING OF A WINDOW OF OPPORTUNITY FOR A MAJORITY OF OUR
FORECAST AREA TO HAVE AT LEAST SOME CHANCE SHOWERS/THUNDERSTORMS.
BECAUSE THE GFS IS FASTER AND NOT AS DEEP WITH THE LOW/TROUGH...IT
DEPICTS A SMALLER WINDOW OF OPPORTUNITY... ENDING SUNDAY MORNING
OVER OUR EASTERNMOST AREAS...AND KEEPS QPF PRETTY MUCH EAST OF THE
LOWER COLORADO RIVER VALLEY. THE ECMWF DEPICTS QPF INTO SOUTHEAST
CALIFORNIA AND ENDS IT SUNDAY NIGHT. BOTH TRACK THE BRUNT OF THE
SYSTEM TO OUR NORTH KEEPING THE JET AXIS JUST TO OUR NORTH.
ACCORDINGLY...WE ONLY GET BRUSHED WITH QG FORCING BUT MAY HAVE SOME
UPPER LEVEL DIFFLUENCE TO WORK WITH IN ADDITION TO CAPE. STRONGER
FLOW ALOFT WILL BRING SOME VERTICAL WIND SHEAR INTO PLAY AS WELL.
BOTH THE GFS AND ECMWF HAVE SUPPORT FROM THEIR RESPECTIVE ENSEMBLES
IN TERMS OF HOW THEY HANDLE THE TROUGH. THE 00Z GFS APPEARS TO HAVE
TRENDED SLIGHTLY SLOWER FROM THE 12Z RUN. STILL A LOT OF UNCERTAINTY
WITH HOW THE TROUGH WILL PLAY OUT AND WHAT THE MOISTURE AND CAPE
WILL BE LIKE. HOWEVER...ENOUGH TO GO ON IN ORDER TO MAKE UPWARD
ADJUSTMENTS TO THE POPS. TEMPS WILL TREND DOWN AS WELL.


&&

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

DRY CONDITIONS AND CLEAR TO MOSTLY CLEAR SKIES WILL CONTINUE THROUGH
MONDAY NIGHT. EXPECTING LIGHT WINDS AND FAIRLY TYPICAL DIURNAL WIND
SHIFTS TODAY WITH THE EXCEPTION OF LINGERING WESTERLY WINDS ACROSS
ALL BUT EASTERN PORTIONS OF THE PHOENIX AREA THROUGH AROUND DAYBREAK
THIS MORNING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
MOISTURE RETREAT DUE TO WESTERLY FLOW WILL KEEP STORM CHANCES
MINIMAL THROUGH THURSDAY AND LIMITED TO THE HIGHER MOUNTAINS OF
SOUTH-CENTRAL ARIZONA. MEANWHILE...TEMPERATURES NUDGE UPWARD A FEW
DEGREES ABOVE NORMAL. HUMIDITIES ON THE LOWER DESERTS DROP BELOW 15
PERCENT THOUGH MAX HUMIDITIES REMAIN FAIR. NO STRONG WINDS ARE
EXPECTED DURING THIS TIME FRAME. ON FRIDAY...A PACIFIC WEATHER
SYSTEM WILL PULL MOISTURE NORTHWARD OVER THE REGION FOR A RETURN OF
STORM CHANCES INTO NEXT WEEKEND...MAINLY EAST OF THE LOWER COLORADO
RIVER VALLEY. IN ADDITION...COOLER TEMPERATURES...HIGHER
HUMIDITIES...AND BREEZY TO LOCALLY WINDY CONDITIONS CAN BE EXPECTED
AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

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






000
FXUS65 KPSR 221658
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
955 AM MST MON SEP 22 2014

.SYNOPSIS...
SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE
HIGHER MOUNTAINS OF SOUTH-CENTRAL ARIZONA THROUGH THURSDAY.
TEMPERATURES WILL TREND UPWARD A FEW DEGREES BY WEDNESDAY. AN
APPROACHING PACIFIC WEATHER SYSTEM LIKELY AFFECTING THE DESERT
SOUTHWEST ON FRIDAY THROUGH SUNDAY WILL LEAD TO A RETURN OF STORM
CHANCES ALONG WITH COOLER TEMPERATURES.

&&

.DISCUSSION...
A GOOD SWATH OF MID LEVEL CLOUDINESS HANGING OVER SOUTH-CENTRAL
ARIZONA THIS MORNING...WITH EVEN SOME LINGERING CONVECTION NEAR THE
NEW MEXICO BORDER. THIS CLOUD COVER WILL THIN OUT AS MORNING
PROGRESSES...BUT VARYING AMOUNTS OF PRECIPITABLE WATER WILL CONTINUE
TO HANG ON OVER THE REGION. PER THE KTWC 12 SOUNDING AND REGIONAL
UPPER AIR PLOTS...THIS BEST MOISTURE BOUNDARY/GRADIENT IS SET UP
OVER THE EASTERN HALF OF ARIZONA...WITH A DENSE MIXING RATIO
GRADIENT OF 10-13G/KG ALONG THE AZ-NM BORDER. MODELS SUGGEST THAT
THE UPPER LEVEL RIDGE AXIS WILL ESTABLISH AND REMAIN OVER THE
INTERMOUNTAIN WEST THROUGH AT LEAST WEDNESDAY...WITH LITTLE
ADDITIONAL DRYING OF THE ATMOSPHERE THAT WILL TAKE PLACE. THE
ANTICYCLONIC FLOW WILL BE ABLE TO IMPORT SOME LOW AND MID LEVEL
MOISTURE FROM TIME TO TIME...AND THIS WILL BE ENOUGH TO SUPPORT A
DAILY ROUND OF ISOLATED/WIDELY SCATTERED THUNDERSTORMS OVER THE
HIGHER TERRAIN WELL EAST OF PHOENIX. AS SUCH...WILL CONTINUE WITH
SLIGHT CHANCE POPS FOR ONLY OUR FAR EASTERN ZONES...KEEPING ALL
OTHER AREAS OF SOUTHWEST AZ AND SOUTHEAST CA DRY THROUGH THURSDAY.
DAYTIME TEMPERATURES WILL ALSO NUDGE UPWARD A FEW DEGREES ABOVE
NORMAL THROUGH MID-WEEK...TOPPING OUT IN THE 104 TO 108 DEGREE RANGE
FOR THE LOWER DESERTS. MADE A FEW MINOR ADJUSTMENTS TO THE NEAR TERM
DIGITAL FORECAST TO BETTER REFLECT CURRENT SATELLITE AND SURFACE OB
TRENDS. PREVIOUS DISCUSSION STILL APPLIES.

PREVIOUS DISCUSSION...
THURSDAY THROUGH SUNDAY...AMPLIFICATION OF THE FLOW PATTERN ON
THURSDAY WILL FORCE A LARGE PACIFIC TROUGH TO SHIFT SOUTHEASTWARD
AND THE RIDGE OVER US TO SHIFT NORTHEASTWARD. IN THE PROCESS...
MOISTURE OVER SOUTHEAST ARIZONA SHIFTS WESTWARD AND SOME DRIER AIR
FROM THE NORTH MIXES IN. STILL ENOUGH MOISTURE ON BALANCE TO
MAINTAIN THE SLIGHT CHANCES OVER ZONE 24 BUT NOT ENOUGH YET TO
INTRODUCE POPS TO THE LOWER DESERTS. BY FRIDAY...GFS AND ECMWF SHOW
MORE DISTINCT DIFFERENCES WITH THE SLOWLY ADVANCING TROUGH. THE GFS
IS FASTER WITH THE INLAND MOVEMENT WHILE THE ECMWF IS DEEPER AND
SLOWER. THIS HAS BEEN THE CASE FOR MULTIPLE RUNS. OF NOTE HOWEVER...
THEY BOTH DEPICT DEEPER MOISTURE BEING PULLED NORTHWARD THOUGH THE
ECMWF IS MORE GENEROUS...AS IS OFTEN THE CASE. THUS FRIDAY LOOKS TO
BE THE BEGINNING OF A WINDOW OF OPPORTUNITY FOR A MAJORITY OF OUR
FORECAST AREA TO HAVE AT LEAST SOME CHANCE SHOWERS/THUNDERSTORMS.
BECAUSE THE GFS IS FASTER AND NOT AS DEEP WITH THE LOW/TROUGH...IT
DEPICTS A SMALLER WINDOW OF OPPORTUNITY... ENDING SUNDAY MORNING
OVER OUR EASTERNMOST AREAS...AND KEEPS QPF PRETTY MUCH EAST OF THE
LOWER COLORADO RIVER VALLEY. THE ECMWF DEPICTS QPF INTO SOUTHEAST
CALIFORNIA AND ENDS IT SUNDAY NIGHT. BOTH TRACK THE BRUNT OF THE
SYSTEM TO OUR NORTH KEEPING THE JET AXIS JUST TO OUR NORTH.
ACCORDINGLY...WE ONLY GET BRUSHED WITH QG FORCING BUT MAY HAVE SOME
UPPER LEVEL DIFFLUENCE TO WORK WITH IN ADDITION TO CAPE. STRONGER
FLOW ALOFT WILL BRING SOME VERTICAL WIND SHEAR INTO PLAY AS WELL.
BOTH THE GFS AND ECMWF HAVE SUPPORT FROM THEIR RESPECTIVE ENSEMBLES
IN TERMS OF HOW THEY HANDLE THE TROUGH. THE 00Z GFS APPEARS TO HAVE
TRENDED SLIGHTLY SLOWER FROM THE 12Z RUN. STILL A LOT OF UNCERTAINTY
WITH HOW THE TROUGH WILL PLAY OUT AND WHAT THE MOISTURE AND CAPE
WILL BE LIKE. HOWEVER...ENOUGH TO GO ON IN ORDER TO MAKE UPWARD
ADJUSTMENTS TO THE POPS. TEMPS WILL TREND DOWN AS WELL.


&&

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

DRY CONDITIONS AND CLEAR TO MOSTLY CLEAR SKIES WILL CONTINUE THROUGH
MONDAY NIGHT. EXPECTING LIGHT WINDS AND FAIRLY TYPICAL DIURNAL WIND
SHIFTS TODAY WITH THE EXCEPTION OF LINGERING WESTERLY WINDS ACROSS
ALL BUT EASTERN PORTIONS OF THE PHOENIX AREA THROUGH AROUND DAYBREAK
THIS MORNING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
MOISTURE RETREAT DUE TO WESTERLY FLOW WILL KEEP STORM CHANCES
MINIMAL THROUGH THURSDAY AND LIMITED TO THE HIGHER MOUNTAINS OF
SOUTH-CENTRAL ARIZONA. MEANWHILE...TEMPERATURES NUDGE UPWARD A FEW
DEGREES ABOVE NORMAL. HUMIDITIES ON THE LOWER DESERTS DROP BELOW 15
PERCENT THOUGH MAX HUMIDITIES REMAIN FAIR. NO STRONG WINDS ARE
EXPECTED DURING THIS TIME FRAME. ON FRIDAY...A PACIFIC WEATHER
SYSTEM WILL PULL MOISTURE NORTHWARD OVER THE REGION FOR A RETURN OF
STORM CHANCES INTO NEXT WEEKEND...MAINLY EAST OF THE LOWER COLORADO
RIVER VALLEY. IN ADDITION...COOLER TEMPERATURES...HIGHER
HUMIDITIES...AND BREEZY TO LOCALLY WINDY CONDITIONS CAN BE EXPECTED
AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

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







000
FXUS65 KPSR 221112
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
410 AM MST MON SEP 22 2014

.SYNOPSIS...
SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE
HIGHER MOUNTAINS OF SOUTH-CENTRAL ARIZONA THROUGH THURSDAY.
TEMPERATURES WILL TREND UPWARD A FEW DEGREES BY WEDNESDAY. AN
APPROACHING PACIFIC WEATHER SYSTEM LIKELY AFFECTING THE DESERT
SOUTHWEST ON FRIDAY THROUGH SUNDAY WILL LEAD TO A RETURN OF STORM
CHANCES ALONG WITH COOLER TEMPERATURES.

&&

.DISCUSSION...
TODAY THROUGH WEDNESDAY...
THE LOW PRESSURE SYSTEM THAT SPREAD DRIER AIR ACROSS MUCH OF THE
REGION YESTERDAY WAS CENTERED NEAR THE UTAH/IDAHO BORDER EARLY THIS
MORNING. THE EASTWARD ADVANCE OF THE DRIER AIR HAS SLOWED ITS
EASTWARD PROGRESS PER IR IMAGERY SHOWING LINGERING CLOUDINESS OVER
THE EASTERN THIRD OF ARIZONA...WITH EVEN SOME LINGERING CONVECTION
NEAR THE NEW MEXICO BORDER. PRECIPITABLE WATER TREND...PER BLENDED
TPW IMAGERY...SHOWS THIS AS WELL. THE LOW IS UNDERCUTTING A RIDGE
CENTERED OVER THE CANADIAN ROCKIES. MEANWHILE...A COLD FRONT WAS
PUSHING SOUTHWARD ACROSS THE GREAT PLAINS AND BEGINNING TO PUSH UP
AGAINST THE SOUTHERN ROCKIES. OVER THE NORTH PACIFIC THERE IS
SOMETHING OF A REX PATTERN WITH TROUGHING...AND EMBEDDED LOWS...OVER
THE NORTHEAST PACIFIC AND A NARROW HIGH AMPLITUDE RIDGE UPSTREAM OF
IT AND JET ENERGY UNDERCUTTING THE RIDGE.

MODELS SHOW THE UPPER LOW TO OUR NORTH CONTINUING TO SHIFT EASTWARD
WITH A RIDGE AXIS BUILDING OVER THE INTERIOR WESTERN STATES. THEY
ALSO AGREE THAT THERE WILL BE ONLY MODEST ADDITIONAL DRYING OVER THE
FORECAST AREA AS THE BACKDOOR FRONT WILL TEND TO COUNTERACT DRIER
WESTERLY WINDS. THIS LEAVES EAST-CENTRAL AND SOUTHEAST ARIZONA WITH
PRETTY DECENT MOISTURE. THE RESULT FOR OUR FORECAST AREA WILL BE
JUST ENOUGH MOISTURE LEFT OVER OUR HIGHER TERRAIN ZONE TO HANG ON TO
SLIGHT CHANCE POPS THERE THROUGH WEDNESDAY. TEMPS NUDGE UPWARD AT
LEAST A FEW DEGREES ABOVE NORMAL BY WEDNESDAY.

THURSDAY THROUGH SUNDAY...
ON THURSDAY...AMPLIFICATION OF THE FLOW PATTERN LEADS TO A LARGE
PACIFIC TROUGH BEGINNING TO SHIFT SOUTHEASTWARD AND THE RIDGE OVER
US SHIFTING NORTHEASTWARD. IN THE PROCESS...MOISTURE OVER SOUTHEAST
ARIZONA SHIFTS WESTWARD AND SOME DRIER AIR FROM THE NORTH MIXES IN.
STILL ENOUGH MOISTURE ON BALANCE TO MAINTAIN THE SLIGHT CHANCES OVER
ZONE 24 BUT NOT ENOUGH YET TO INTRODUCE POPS TO THE LOWER DESERTS.
BY FRIDAY...GFS AND ECMWF SHOW MORE DISTINCT DIFFERENCES WITH THE
SLOWLY ADVANCING TROUGH. THE GFS IS FASTER WITH THE INLAND MOVEMENT
WHILE THE ECMWF IS DEEPER AND SLOWER. THIS HAS BEEN THE CASE FOR
MULTIPLE RUNS. OF NOTE HOWEVER...THEY BOTH DEPICT DEEPER MOISTURE
BEING PULLED NORTHWARD THOUGH THE ECMWF IS MORE GENEROUS...AS IS
OFTEN THE CASE. THUS FRIDAY LOOKS TO BE THE BEGINNING OF A WINDOW OF
OPPORTUNITY FOR A MAJORITY OF OUR FORECAST AREA TO HAVE AT LEAST
SOME SORT OF CHANCE FOR SHOWERS/THUNDERSTORMS. BECAUSE THE GFS IS
FASTER AND NOT AS DEEP WITH THE LOW/TROUGH...IT DEPICTS A SMALLER
WINDOW OF OPPORTUNITY...ENDING SUNDAY MORNING OVER OUR EASTERNMOST
AREAS...AND KEEPS QPF PRETTY MUCH EAST OF THE LOWER COLORADO RIVER
VALLEY. THE ECMWF DEPICTS QPF INTO SOUTHEAST CALIFORNIA AND ENDS IT
SUNDAY NIGHT. BOTH TRACK THE BRUNT OF THE SYSTEM TO OUR NORTH
KEEPING THE JET AXIS JUST TO OUR NORTH. ACCORDINGLY...WE ONLY GET
BRUSHED WITH QG FORCING BUT MAY HAVE SOME UPPER LEVEL DIFFLUENCE TO
WORK WITH IN ADDITION TO CAPE. STRONGER FLOW ALOFT WILL BRING SOME
VERTICAL WIND SHEAR INTO PLAY AS WELL. BOTH THE GFS AND ECMWF HAVE
SUPPORT FROM THEIR RESPECTIVE ENSEMBLES IN TERMS OF HOW THEY HANDLE
THE TROUGH. THE 00Z GFS APPEARS TO HAVE TRENDED SLIGHTLY SLOWER FROM
THE 12Z RUN. STILL A LOT OF UNCERTAINTY WITH HOW THE TROUGH WILL
PLAY OUT AND WHAT THE MOISTURE AND CAPE WILL BE LIKE.
HOWEVER...ENOUGH TO GO ON IN ORDER TO MAKE UPWARD ADJUSTMENTS TO THE
POPS. TEMPS WILL TREND DOWN AS WELL.


&&

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

DRY CONDITIONS AND CLEAR TO MOSTLY CLEAR SKIES WILL CONTINUE THROUGH
MONDAY NIGHT. EXPECTING LIGHT WINDS AND FAIRLY TYPICAL DIURNAL WIND
SHIFTS TODAY WITH THE EXCEPTION OF LINGERING WESTERLY WINDS ACROSS
ALL BUT EASTERN PORTIONS OF THE PHOENIX AREA THROUGH AROUND DAYBREAK
THIS MORNING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
MOISTURE RETREAT DUE TO WESTERLY FLOW WILL KEEP STORM CHANCES
MINIMAL THROUGH THURSDAY AND LIMITED TO THE HIGHER MOUNTAINS OF
SOUTH-CENTRAL ARIZONA. MEANWHILE...TEMPERATURES NUDGE UPWARD A FEW
DEGREES ABOVE NORMAL. HUMIDITIES ON THE LOWER DESERTS DROP BELOW 15
PERCENT THOUGH MAX HUMIDITIES REMAIN FAIR. NO STRONG WINDS ARE
EXPECTED DURING THIS TIME FRAME. ON FRIDAY...A PACIFIC WEATHER
SYSTEM WILL PULL MOISTURE NORTHWARD OVER THE REGION FOR A RETURN OF
STORM CHANCES INTO NEXT WEEKEND...MAINLY EAST OF THE LOWER COLORADO
RIVER VALLEY. IN ADDITION...COOLER TEMPERATURES...HIGHER
HUMIDITIES...AND BREEZY TO LOCALLY WINDY CONDITIONS CAN BE EXPECTED
AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

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








000
FXUS65 KPSR 221112
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
410 AM MST MON SEP 22 2014

.SYNOPSIS...
SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE
HIGHER MOUNTAINS OF SOUTH-CENTRAL ARIZONA THROUGH THURSDAY.
TEMPERATURES WILL TREND UPWARD A FEW DEGREES BY WEDNESDAY. AN
APPROACHING PACIFIC WEATHER SYSTEM LIKELY AFFECTING THE DESERT
SOUTHWEST ON FRIDAY THROUGH SUNDAY WILL LEAD TO A RETURN OF STORM
CHANCES ALONG WITH COOLER TEMPERATURES.

&&

.DISCUSSION...
TODAY THROUGH WEDNESDAY...
THE LOW PRESSURE SYSTEM THAT SPREAD DRIER AIR ACROSS MUCH OF THE
REGION YESTERDAY WAS CENTERED NEAR THE UTAH/IDAHO BORDER EARLY THIS
MORNING. THE EASTWARD ADVANCE OF THE DRIER AIR HAS SLOWED ITS
EASTWARD PROGRESS PER IR IMAGERY SHOWING LINGERING CLOUDINESS OVER
THE EASTERN THIRD OF ARIZONA...WITH EVEN SOME LINGERING CONVECTION
NEAR THE NEW MEXICO BORDER. PRECIPITABLE WATER TREND...PER BLENDED
TPW IMAGERY...SHOWS THIS AS WELL. THE LOW IS UNDERCUTTING A RIDGE
CENTERED OVER THE CANADIAN ROCKIES. MEANWHILE...A COLD FRONT WAS
PUSHING SOUTHWARD ACROSS THE GREAT PLAINS AND BEGINNING TO PUSH UP
AGAINST THE SOUTHERN ROCKIES. OVER THE NORTH PACIFIC THERE IS
SOMETHING OF A REX PATTERN WITH TROUGHING...AND EMBEDDED LOWS...OVER
THE NORTHEAST PACIFIC AND A NARROW HIGH AMPLITUDE RIDGE UPSTREAM OF
IT AND JET ENERGY UNDERCUTTING THE RIDGE.

MODELS SHOW THE UPPER LOW TO OUR NORTH CONTINUING TO SHIFT EASTWARD
WITH A RIDGE AXIS BUILDING OVER THE INTERIOR WESTERN STATES. THEY
ALSO AGREE THAT THERE WILL BE ONLY MODEST ADDITIONAL DRYING OVER THE
FORECAST AREA AS THE BACKDOOR FRONT WILL TEND TO COUNTERACT DRIER
WESTERLY WINDS. THIS LEAVES EAST-CENTRAL AND SOUTHEAST ARIZONA WITH
PRETTY DECENT MOISTURE. THE RESULT FOR OUR FORECAST AREA WILL BE
JUST ENOUGH MOISTURE LEFT OVER OUR HIGHER TERRAIN ZONE TO HANG ON TO
SLIGHT CHANCE POPS THERE THROUGH WEDNESDAY. TEMPS NUDGE UPWARD AT
LEAST A FEW DEGREES ABOVE NORMAL BY WEDNESDAY.

THURSDAY THROUGH SUNDAY...
ON THURSDAY...AMPLIFICATION OF THE FLOW PATTERN LEADS TO A LARGE
PACIFIC TROUGH BEGINNING TO SHIFT SOUTHEASTWARD AND THE RIDGE OVER
US SHIFTING NORTHEASTWARD. IN THE PROCESS...MOISTURE OVER SOUTHEAST
ARIZONA SHIFTS WESTWARD AND SOME DRIER AIR FROM THE NORTH MIXES IN.
STILL ENOUGH MOISTURE ON BALANCE TO MAINTAIN THE SLIGHT CHANCES OVER
ZONE 24 BUT NOT ENOUGH YET TO INTRODUCE POPS TO THE LOWER DESERTS.
BY FRIDAY...GFS AND ECMWF SHOW MORE DISTINCT DIFFERENCES WITH THE
SLOWLY ADVANCING TROUGH. THE GFS IS FASTER WITH THE INLAND MOVEMENT
WHILE THE ECMWF IS DEEPER AND SLOWER. THIS HAS BEEN THE CASE FOR
MULTIPLE RUNS. OF NOTE HOWEVER...THEY BOTH DEPICT DEEPER MOISTURE
BEING PULLED NORTHWARD THOUGH THE ECMWF IS MORE GENEROUS...AS IS
OFTEN THE CASE. THUS FRIDAY LOOKS TO BE THE BEGINNING OF A WINDOW OF
OPPORTUNITY FOR A MAJORITY OF OUR FORECAST AREA TO HAVE AT LEAST
SOME SORT OF CHANCE FOR SHOWERS/THUNDERSTORMS. BECAUSE THE GFS IS
FASTER AND NOT AS DEEP WITH THE LOW/TROUGH...IT DEPICTS A SMALLER
WINDOW OF OPPORTUNITY...ENDING SUNDAY MORNING OVER OUR EASTERNMOST
AREAS...AND KEEPS QPF PRETTY MUCH EAST OF THE LOWER COLORADO RIVER
VALLEY. THE ECMWF DEPICTS QPF INTO SOUTHEAST CALIFORNIA AND ENDS IT
SUNDAY NIGHT. BOTH TRACK THE BRUNT OF THE SYSTEM TO OUR NORTH
KEEPING THE JET AXIS JUST TO OUR NORTH. ACCORDINGLY...WE ONLY GET
BRUSHED WITH QG FORCING BUT MAY HAVE SOME UPPER LEVEL DIFFLUENCE TO
WORK WITH IN ADDITION TO CAPE. STRONGER FLOW ALOFT WILL BRING SOME
VERTICAL WIND SHEAR INTO PLAY AS WELL. BOTH THE GFS AND ECMWF HAVE
SUPPORT FROM THEIR RESPECTIVE ENSEMBLES IN TERMS OF HOW THEY HANDLE
THE TROUGH. THE 00Z GFS APPEARS TO HAVE TRENDED SLIGHTLY SLOWER FROM
THE 12Z RUN. STILL A LOT OF UNCERTAINTY WITH HOW THE TROUGH WILL
PLAY OUT AND WHAT THE MOISTURE AND CAPE WILL BE LIKE.
HOWEVER...ENOUGH TO GO ON IN ORDER TO MAKE UPWARD ADJUSTMENTS TO THE
POPS. TEMPS WILL TREND DOWN AS WELL.


&&

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

DRY CONDITIONS AND CLEAR TO MOSTLY CLEAR SKIES WILL CONTINUE THROUGH
MONDAY NIGHT. EXPECTING LIGHT WINDS AND FAIRLY TYPICAL DIURNAL WIND
SHIFTS TODAY WITH THE EXCEPTION OF LINGERING WESTERLY WINDS ACROSS
ALL BUT EASTERN PORTIONS OF THE PHOENIX AREA THROUGH AROUND DAYBREAK
THIS MORNING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
MOISTURE RETREAT DUE TO WESTERLY FLOW WILL KEEP STORM CHANCES
MINIMAL THROUGH THURSDAY AND LIMITED TO THE HIGHER MOUNTAINS OF
SOUTH-CENTRAL ARIZONA. MEANWHILE...TEMPERATURES NUDGE UPWARD A FEW
DEGREES ABOVE NORMAL. HUMIDITIES ON THE LOWER DESERTS DROP BELOW 15
PERCENT THOUGH MAX HUMIDITIES REMAIN FAIR. NO STRONG WINDS ARE
EXPECTED DURING THIS TIME FRAME. ON FRIDAY...A PACIFIC WEATHER
SYSTEM WILL PULL MOISTURE NORTHWARD OVER THE REGION FOR A RETURN OF
STORM CHANCES INTO NEXT WEEKEND...MAINLY EAST OF THE LOWER COLORADO
RIVER VALLEY. IN ADDITION...COOLER TEMPERATURES...HIGHER
HUMIDITIES...AND BREEZY TO LOCALLY WINDY CONDITIONS CAN BE EXPECTED
AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

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







000
FXUS65 KPSR 220308
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
810 PM MST SUN SEP 21 2014

.SYNOPSIS...
DRIER AIR WILL GRADUALLY FILTER INTO THE REGION THROUGH MID WEEK
LEADING TO DRASTIC DECLINE IN STORM CHANCES. SLIGHT CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE HIGHER MOUNTAINS
OF SOUTH-CENTRAL ARIZONA THROUGH MONDAY. SLIGHTLY ABOVE NORMAL
TEMPERATURES ARE ANTICIPATED THROUGH THE MIDDLE OF THIS WEEK. AN
APPROACHING PACIFIC WEATHER SYSTEM LIKELY AFFECTING THE DESERT
SOUTHWEST ON FRIDAY AND SATURDAY WILL LEAD TO AN INCREASE IN STORM
CHANCES AND COOLER TEMPERATURES.

&&

.DISCUSSION...
THE VIGOROUS PACIFIC TROF OVER CENTRAL AND SOUTHERN CA YESTERDAY
CONTINUED ITS NORTHEASTWARD TRACK INTO NORTHEAST NV TODAY. IN ITS
WAKE AT OUR LATITUDE...A DRIER BOUNDARY LAYER AND MORE STABLE UPPER
LEVEL WINDS MOVED INTO MOST OF SOUTHWEST AND SOUTH CENTRAL AZ FOR
NEARLY CLEAR SKIES. THE EXCEPTION WAS IN EASTERN AZ...INCLUDING THE
FAR PORTIONS OF OUR ZONE 24 SOUTHERN GILA COUNTY WHERE A FEW MTN
TSTMS DEVELOPED IN REMNANT MONSOON MOISTURE. CONVECTIVE THREATS WILL
END OVER SOUTHERN GILA COUNTY IN A FEW HOURS. OTHERWISE DRY AND
WARMER DAYS ARE EXPECTED THROUGH TUESDAY.

MINOR UPDATES TO FIRST PERIOD FORECASTS WERE SENT EARLIER. PREVIOUS
DISCUSSION BELOW STILL APPLIES.


.PREVIOUS DISCUSSION...245 PM MST...
EARLY AFTERNOON RADAR IMAGERY FILLING IN WITH THUNDERSTORMS ALONG
THE EASTERN HALF OF ARIZONA IN THE WHITE MOUNTAINS FROM COCHISE
COUNTY NORTH THROUGH PORTIONS OF COCONINO COUNTY AND NORTHERN
PORTIONS OF MOHAVE COUNTY. FROM SOUTHEAST CALIFORNIA THROUGH THE
EAST VALLEY OF THE GREATER PHOENIX METRO MOSTLY CLEAR SKIES HAVE
BEEN THE STORY TODAY WITH STEADY OR FALLING DEWPOINT VALUES. AS OF
215 PM MST/PDT THE DEWPOINT AT SKY HARBOR IS SITTING AT 49F
/9C/...SO IT IS EVIDENT THERE IS A BOUNDARY OF DRY AIR WORKING INTO
ARIZONA AND SLOWLY PUSHING EAST. DO NOT EXPECT SHOWERS IN THE METRO
AREA OR CENTRAL DESERTS THIS EVENING WITH A WESTERLY FLOW AND
MINIMAL MOISTURE /1000-700 MB MIXING RATIOS BELOW 8 G/KG/.

GRADUAL RISING HEIGHTS THROUGH MOST OF THE WEEK...UNDER A 591 DM
RIDGE OF HIGH PRESSURE AND DOMINATING WESTERLY FLOW ALOFT...WILL
ALLOW TEMPERATURES TO RISE A DEGREE OR TWO EACH DAY BY THURSDAY.

FOR THE EXTENDED PART OF THE FORECAST LATER THIS WEEK...A LARGE
PACIFIC TROUGH WILL MOVE ON SHORE FROM THE GULF OF ALASKA BRINGING A
COOLER AND DRIER AIR MASS DOWN THROUGH THE GREAT BASIN AND INTO THE
DESERT SOUTHWEST. MODEL RUN TO RUN CONSISTENCY HAS BEEN DECENT WITH
OPERATIONAL MODELS IN GOOD AGREEMENT THIS FAR OUT IN THE EXTENDED.
MINOR DIFFERENCES IN TIMING AND STRENGTH...BUT THE OVERALL PLACEMENT
AND TIMING LOOKS GOOD. PRECIP CHANCES WILL BEGIN A RAMP UP STARTING
FRIDAY AFTERNOON THROUGH EARLY SUNDAY...SO MADE UPWARD TREND CHANGES
TO THE FORECAST AT THIS TIME. BY SUNDAY THOUGH MODELS BEGIN TO
DRASTICALLY DIFFER...WITH THE GFS TAKING THE TROUGH EASTWARD ACROSS
THE ROCKIES AND THE ECMWF KEEPING THE CUT OFF LOW CENTERED OVER
WESTERN NEVADA WITH SLOW FORWARD PROPAGATION. THESE DIFFERENCES
COULD MEAN CHANGES TO PRECIP FOR THE SOUTHWEST SO CONFIDENCE IS
PRETTY LOW THAT FAR OUT.

&&

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

DRIER WESTERLY FLOW ALOFT WILL RESULT IN MOSTLY CLEAR SKIES AND
LIGHT WIND THROUGH AT LEAST 19Z MONDAY.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
MOISTURE RETREAT DUE TO WESTERLY FLOW WILL KEEP STORM CHANCES
MINIMAL THROUGH THURSDAY AND LIMITED TO THE HIGHER MOUNTAINS OF
SOUTH-CENTRAL ARIZONA. MEANWHILE...TEMPERATURES NUDGE UPWARD A FEW
DEGREES ABOVE NORMAL. HUMIDITIES ON THE LOWER DESERTS DROP BELOW 15
PERCENT THOUGH MAX HUMIDITIES REMAIN FAIR. NO STRONG WINDS ARE
EXPECTED DURING THIS TIME FRAME. ON FRIDAY...A PACIFIC WEATHER
SYSTEM WILL PULL MOISTURE NORTHWARD OVER THE REGION FOR A RETURN OF
STORM CHANCES INTO NEXT WEEKEND...MAINLY EAST OF THE LOWER COLORADO
RIVER VALLEY. IN ADDITION...COOLER TEMPERATURES...HIGHER
HUMIDITIES...AND BREEZY TO LOCALLY WINDY CONDITIONS CAN BE EXPECTED
AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...VASQUEZ/DEWEY
AVIATION...VASQUEZ
FIRE WEATHER...MEYERS/AJ











000
FXUS65 KPSR 212143 AAA
AFDPSR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PHOENIX AZ
245 PM MST SUN SEP 21 2014

.SYNOPSIS...
DRIER AIR WILL GRADUALLY FILTER INTO THE REGION THROUGH MID WEEK
LEADING TO DRASTIC DECLINE IN STORM CHANCES. SLIGHT CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE HIGHER MOUNTAINS
OF SOUTH-CENTRAL ARIZONA THROUGH MONDAY. SLIGHTLY ABOVE NORMAL
TEMPERATURES ARE ANTICIPATED THROUGH THE MIDDLE OF THIS WEEK. AN
APPROACHING PACIFIC WEATHER SYSTEM LIKELY AFFECTING THE DESERT
SOUTHWEST ON FRIDAY AND SATURDAY WILL LEAD TO AN INCREASE IN STORM
CHANCES AND COOLER TEMPERATURES.

&&

.DISCUSSION...
EARLY AFTERNOON RADAR IMAGERY FILLING IN WITH THUNDERSTORMS ALONG
THE EASTERN HALF OF ARIZONA IN THE WHITE MOUNTAINS FROM COCHISE
COUNTY NORTH THROUGH PORTIONS OF COCONINO COUNTY AND NORTHERN
PORTIONS OF MOHAVE COUNTY. FROM SOUTHEAST CALIFORNIA THROUGH THE
EAST VALLEY OF THE GREATER PHOENIX METRO MOSTLY CLEAR SKIES HAVE
BEEN THE STORY TODAY WITH STEADY OR FALLING DEWPOINT VALUES. AS OF
215 PM MST/PDT THE DEWPOINT AT SKY HARBOR IS SITTING AT 49F
/9C/...SO IT IS EVIDENT THERE IS A BOUNDARY OF DRY AIR WORKING INTO
ARIZONA AND SLOWLY PUSHING EAST. DO NOT EXPECT SHOWERS IN THE METRO
AREA OR CENTRAL DESERTS THIS EVENING WITH A WESTERLY FLOW AND
MINIMAL MOISTURE /1000-700 MB MIXING RATIOS BELOW 8 G/KG/.

GRADUAL RISING HEIGHTS THROUGH MOST OF THE WEEK...UNDER A 591 DM
RIDGE OF HIGH PRESSURE AND DOMINATING WESTERLY FLOW ALOFT...WILL
ALLOW TEMPERATURES TO RISE A DEGREE OR TWO EACH DAY BY THURSDAY.

FOR THE EXTENDED PART OF THE FORECAST LATER THIS WEEK...A LARGE
PACIFIC TROUGH WILL MOVE ON SHORE FROM THE GULF OF ALASKA BRINGING A
COOLER AND DRIER AIR MASS DOWN THROUGH THE GREAT BASIN AND INTO THE
DESERT SOUTHWEST. MODEL RUN TO RUN CONSISTENCY HAS BEEN DECENT WITH
OPERATIONAL MODELS IN GOOD AGREEMENT THIS FAR OUT IN THE EXTENDED.
MINOR DIFFERENCES IN TIMING AND STRENGTH...BUT THE OVERALL PLACEMENT
AND TIMING LOOKS GOOD. PRECIP CHANCES WILL BEGIN A RAMP UP STARTING
FRIDAY AFTERNOON THROUGH EARLY SUNDAY...SO MADE UPWARD TREND CHANGES
TO THE FORECAST AT THIS TIME. BY SUNDAY THOUGH MODELS BEGIN TO
DRASTICALLY DIFFER...WITH THE GFS TAKING THE TROUGH EASTWARD ACROSS
THE ROCKIES AND THE ECMWF KEEPING THE CUT OFF LOW CENTERED OVER
WESTERN NEVADA WITH SLOW FORWARD PROPAGATION. THESE DIFFERENCES
COULD MEAN CHANGES TO PRECIP FOR THE SOUTHWEST SO CONFIDENCE IS
PRETTY LOW THAT FAR OUT.

&&

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

MOSTLY CLEAR SKIES WILL PREVAIL THIS EVENING/OVERNIGHT AS DRIER AIR
OVERSPREADS THE AREA. EXPECT LIGHT WINDS 10KT OR LESS AT ALL
TERMINALS THROUGH AT LEAST MONDAY AFTERNOON. ANY THUNDERSTORM THREAT
THIS AFTERNOON/EVENING WILL REMAIN OVER THE HIGHER TERRAIN OF
EASTERN ARIZONA.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
MOISTURE RETREAT DUE TO WESTERLY FLOW WILL KEEP STORM CHANCES
MINIMAL THROUGH THURSDAY AND LIMITED TO THE HIGHER MOUNTAINS OF
SOUTH-CENTRAL ARIZONA. MEANWHILE...TEMPERATURES NUDGE UPWARD A FEW
DEGREES ABOVE NORMAL. HUMIDITIES ON THE LOWER DESERTS DROP BELOW 15
PERCENT THOUGH MAX HUMIDITIES REMAIN FAIR. NO STRONG WINDS ARE
EXPECTED DURING THIS TIME FRAME. ON FRIDAY...A PACIFIC WEATHER
SYSTEM WILL PULL MOISTURE NORTHWARD OVER THE REGION FOR A RETURN OF
STORM CHANCES INTO NEXT WEEKEND...MAINLY EAST OF THE LOWER COLORADO
RIVER VALLEY. IN ADDITION...COOLER TEMPERATURES...HIGHER
HUMIDITIES...AND BREEZY TO LOCALLY WINDY CONDITIONS CAN BE EXPECTED
AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

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









000
FXUS65 KPSR 212143 AAA
AFDPSR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PHOENIX AZ
245 PM MST SUN SEP 21 2014

.SYNOPSIS...
DRIER AIR WILL GRADUALLY FILTER INTO THE REGION THROUGH MID WEEK
LEADING TO DRASTIC DECLINE IN STORM CHANCES. SLIGHT CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE HIGHER MOUNTAINS
OF SOUTH-CENTRAL ARIZONA THROUGH MONDAY. SLIGHTLY ABOVE NORMAL
TEMPERATURES ARE ANTICIPATED THROUGH THE MIDDLE OF THIS WEEK. AN
APPROACHING PACIFIC WEATHER SYSTEM LIKELY AFFECTING THE DESERT
SOUTHWEST ON FRIDAY AND SATURDAY WILL LEAD TO AN INCREASE IN STORM
CHANCES AND COOLER TEMPERATURES.

&&

.DISCUSSION...
EARLY AFTERNOON RADAR IMAGERY FILLING IN WITH THUNDERSTORMS ALONG
THE EASTERN HALF OF ARIZONA IN THE WHITE MOUNTAINS FROM COCHISE
COUNTY NORTH THROUGH PORTIONS OF COCONINO COUNTY AND NORTHERN
PORTIONS OF MOHAVE COUNTY. FROM SOUTHEAST CALIFORNIA THROUGH THE
EAST VALLEY OF THE GREATER PHOENIX METRO MOSTLY CLEAR SKIES HAVE
BEEN THE STORY TODAY WITH STEADY OR FALLING DEWPOINT VALUES. AS OF
215 PM MST/PDT THE DEWPOINT AT SKY HARBOR IS SITTING AT 49F
/9C/...SO IT IS EVIDENT THERE IS A BOUNDARY OF DRY AIR WORKING INTO
ARIZONA AND SLOWLY PUSHING EAST. DO NOT EXPECT SHOWERS IN THE METRO
AREA OR CENTRAL DESERTS THIS EVENING WITH A WESTERLY FLOW AND
MINIMAL MOISTURE /1000-700 MB MIXING RATIOS BELOW 8 G/KG/.

GRADUAL RISING HEIGHTS THROUGH MOST OF THE WEEK...UNDER A 591 DM
RIDGE OF HIGH PRESSURE AND DOMINATING WESTERLY FLOW ALOFT...WILL
ALLOW TEMPERATURES TO RISE A DEGREE OR TWO EACH DAY BY THURSDAY.

FOR THE EXTENDED PART OF THE FORECAST LATER THIS WEEK...A LARGE
PACIFIC TROUGH WILL MOVE ON SHORE FROM THE GULF OF ALASKA BRINGING A
COOLER AND DRIER AIR MASS DOWN THROUGH THE GREAT BASIN AND INTO THE
DESERT SOUTHWEST. MODEL RUN TO RUN CONSISTENCY HAS BEEN DECENT WITH
OPERATIONAL MODELS IN GOOD AGREEMENT THIS FAR OUT IN THE EXTENDED.
MINOR DIFFERENCES IN TIMING AND STRENGTH...BUT THE OVERALL PLACEMENT
AND TIMING LOOKS GOOD. PRECIP CHANCES WILL BEGIN A RAMP UP STARTING
FRIDAY AFTERNOON THROUGH EARLY SUNDAY...SO MADE UPWARD TREND CHANGES
TO THE FORECAST AT THIS TIME. BY SUNDAY THOUGH MODELS BEGIN TO
DRASTICALLY DIFFER...WITH THE GFS TAKING THE TROUGH EASTWARD ACROSS
THE ROCKIES AND THE ECMWF KEEPING THE CUT OFF LOW CENTERED OVER
WESTERN NEVADA WITH SLOW FORWARD PROPAGATION. THESE DIFFERENCES
COULD MEAN CHANGES TO PRECIP FOR THE SOUTHWEST SO CONFIDENCE IS
PRETTY LOW THAT FAR OUT.

&&

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

MOSTLY CLEAR SKIES WILL PREVAIL THIS EVENING/OVERNIGHT AS DRIER AIR
OVERSPREADS THE AREA. EXPECT LIGHT WINDS 10KT OR LESS AT ALL
TERMINALS THROUGH AT LEAST MONDAY AFTERNOON. ANY THUNDERSTORM THREAT
THIS AFTERNOON/EVENING WILL REMAIN OVER THE HIGHER TERRAIN OF
EASTERN ARIZONA.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
MOISTURE RETREAT DUE TO WESTERLY FLOW WILL KEEP STORM CHANCES
MINIMAL THROUGH THURSDAY AND LIMITED TO THE HIGHER MOUNTAINS OF
SOUTH-CENTRAL ARIZONA. MEANWHILE...TEMPERATURES NUDGE UPWARD A FEW
DEGREES ABOVE NORMAL. HUMIDITIES ON THE LOWER DESERTS DROP BELOW 15
PERCENT THOUGH MAX HUMIDITIES REMAIN FAIR. NO STRONG WINDS ARE
EXPECTED DURING THIS TIME FRAME. ON FRIDAY...A PACIFIC WEATHER
SYSTEM WILL PULL MOISTURE NORTHWARD OVER THE REGION FOR A RETURN OF
STORM CHANCES INTO NEXT WEEKEND...MAINLY EAST OF THE LOWER COLORADO
RIVER VALLEY. IN ADDITION...COOLER TEMPERATURES...HIGHER
HUMIDITIES...AND BREEZY TO LOCALLY WINDY CONDITIONS CAN BE EXPECTED
AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

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








000
FXUS65 KPSR 211610 AAA
AFDPSR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PHOENIX AZ
910 AM MST SUN SEP 21 2014

.SYNOPSIS...
DRIER AIR WILL GRADUALLY FILTER INTO THE REGION TODAY AND MONDAY
LEADING TO DRASTIC DECLINE IN STORM CHANCES. SLIGHT CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE HIGHER MOUNTAINS
OF SOUTH-CENTRAL ARIZONA THROUGH MONDAY. SLIGHTLY ABOVE NORMAL
TEMPERATURES ARE ANTICIPATED THROUGH THE MIDDLE OF THIS WEEK. AN
APPROACHING PACIFIC WEATHER SYSTEM LIKELY AFFECTING THE DESERT
SOUTHWEST ON FRIDAY AND SATURDAY WILL LEAD TO AN INCREASE IN STORM
CHANCES AND COOLER TEMPERATURES.

&&

.DISCUSSION...
THE UPPER LEVEL CUT OFF LOW IS CENTERED JUST TO THE EAST OF LAKE
TAHOE IN WESTERN NEVADA THIS MORNING PER WATER VAPOR AND IR
SATELLITE IMAGERY. A LARGE AREA OF CLOUD COVER AND SHOWER AND STORM
ACTIVITY IS QUICKLY MOVING NORTHWARD THROUGH NORTHERN
ARIZONA...SOUTHERN NEVADA AND SOUTHERN UTAH AS OF 1545Z THIS
MORNING. PER THE 12Z RAOB FOR KFGZ A VERY MOIST AND SATURATED COLUMN
OF AIR WITH FAIRLY STRONG SOUTHERLY STEERING FLOW...AND AS SUCH FOR
KTWC WITH LITTLE CHANGE TO THE MOISTURE PROFILE KEEPING 1.5 INCH
PWAT AND A MODERATE LOWER LEVEL STEERING FLOW PATTERN. AT KPSR
HOWEVER...A DRASTIC DROP IN MOISTURE WITH PWAT VALUES LOSING OVER
HALF AN INCH COMING IT AT 1.15 INCH. IN CONJUNCTION WITH A DRYING
TREND...MOST AREAS ACROSS THE DESERTS THIS MORNING ARE SEEING
DEWPOINT VALUES SLOWLY COME DOWN TO THE LOWER 60S AND LOWER 50S
UNDER PARTLY CLOUDY SKIES.

WITH THE PROGRESSION OF THE UPPER LEVEL DISTURBANCE TODAY...EXPECT
MOST CONVECTIVE AND SHOWER ACTIVITY WILL REMAIN IN THE EASTERN AND
SOUTHEASTERN HALF OF THE STATE TODAY...WHERE THE BEST DYNAMIC SET UP
WILL REMAIN. ONLY MADE A FEW MINOR UPDATES TO THE FORECAST THIS
MORNING FOR CURRENT TRENDS.

.PREVIOUS DISCUSSION.../ISSUED 217 AM MST/PDT 21 SEPT/...
AS THE UPPER LOW WHICH IS NOW CENTERED OVER CENTRAL CALIFORNIA
CONTINUES TO LIFT NORTHWARD...DRIER SOUTHWESTERLY MID AND UPPER
LEVEL FLOW IS TAKING OVER ACROSS SOUTHWEST AND MUCH OF SOUTH-CENTRAL
ARIZONA. THIS DRIER AIR IS EXPECTED TO PUSH AS FAR EAST AS PHOENIX
BY THIS AFTERNOON...ESSENTIALLY CUTTING OFF ANY RAIN CHANCES EXCEPT
FOR HIGHER TERRAIN AREAS EAST OF PHOENIX. THE UPPER LOW IS FORECAST
TO MOVE INTO THE GREAT BASIN BY THIS EVENING WITH THE UPPER RIDGE TO
OUR SOUTH CREEPING NORTHWARD INTO ARIZONA. GOOD MODEL AGREEMENT
SHOWS THE RIDGE BUILDING OVER THE DESERT SOUTHWEST THE NEXT FEW DAYS
WITH HEIGHTS MAXING OUT IN THE 590-592DM RANGE ON TUESDAY AND
WEDNESDAY. ANY LINGERING LOW LEVEL MOISTURE OVER EAST-CENTRAL
ARIZONA WILL LIKELY GET PUSHED OUT OF THE AREA WHICH SHOULD END ANY
SLIGHT CHANCES FOR RAIN ACROSS THE HIGHER TERRAIN ON TUESDAY AND
WEDNESDAY. THE HIGH HEIGHTS AND DRIER AIR WILL ALLOW FOR SOME
WARMING OVER THE NEXT FEW DAYS WITH LOWER DESERT LOCATIONS PEAKING
OUT IN THE 100-105 RANGE...OR ROUGHLY 3-5 DEGREES ABOVE SEASONAL
NORMALS.

BY LATE IN THE WEEK...THE NEXT WEATHER SYSTEM WILL SLOWLY MOVE
SOUTHEASTWARD INTO THE PACIFIC NORTHWEST AND GREAT BASIN. A GOOD
AMOUNT OF UNCERTAINTY REMAINS WITH THIS SYSTEM WITH LONG RANGE
MODELS STRUGGLING A BIT WITH THE TIMING AND HOW FAR SOUTH THE MAIN
SHORTWAVE WILL GO. LATEST RUNS SHOW A FASTER AND LESS DIGGING TROUGH
FROM THE GFS WHILE THE EUROPEAN DIGS THE TROUGH AS FAR SOUTH AS
SOUTHERN CALIFORNIA WHILE BRIEFLY CUTTING THE LOW OFF FROM THE POLAR
JET STREAM. THE TIMING DOES SEEM TO BE PUSHED BACK FROM YESTERDAY/S
MODEL RUNS...SO THE BEST RAIN CHANCES HAVE SHIFTED FROM FRIDAY TO
SATURDAY. THIS IS REFLECTED IN THE FORECAST BY DECREASING POPS
SLIGHTLY ON FRIDAY AND INCREASING POPS ON SATURDAY. THE AMOUNT OF
MOISTURE THAT WILL GET DRAWN UP AHEAD OF THE SYSTEM IS ALSO
PROBLEMATIC AS THE DEEPER EUROPEAN BRINGS IN SUBSTANTIALLY MORE
MOISTURE THAN THE GFS. FOR NOW...KEEPING WITH A FAIRLY WIDESPREAD
10-20 POPS ON BOTH DAYS. TEMPERATURES WILL BEGIN TO DECREASE
STARTING FRIDAY WITH LOWER DESERT HIGHS LIKELY ONLY IN THE LOWER 90S
FOR NEXT WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL AND SOUTHWEST ARIZONA INCLUDING KPHX...KIWA...KSDL...
STORM CHANCES OVER SOUTHERN ARIZONA TODAY WILL BE EAST OF A LINE
FROM WICKENBURG TO SELLS WITH ONLY SLIGHT CHANCES OVER PHOENIX
METRO. THUS HELD OFF ON INSERTING TEMPO SHWRS/TSTMS IN TAFS.
OUTFLOWS FROM DISTANT STORMS MAY LEAD TO WIND SHIFTS LATER
TODAY...BUT LESS LIKELY THAN YESTERDAY. ANTICIPATE SLOWER ARRIVAL OF
WESTERLY WINDS AT KPHX TODAY THAN YESTERDAY.

SOUTHEAST CALIFORNIA INCLUDING KIPL...AND KBLH...
SOUTH AND SOUTHEASTERLY WINDS WILL BE FAVORED ONCE AGAIN...LESS SO
OVER IMPERIAL VALLEY WITH WESTERLY FAVORED. OTHERWISE CLEAR SKIES.


AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
MOISTURE RETREAT DUE TO WESTERLY FLOW WILL KEEP STORM CHANCES
MINIMAL THROUGH THURSDAY AND LIMITED TO THE HIGHER MOUNTAINS OF
SOUTH-CENTRAL ARIZONA. MEANWHILE...TEMPERATURES NUDGE UPWARD A FEW
DEGREES ABOVE NORMAL. HUMIDITIES ON THE LOWER DESERTS DROP BELOW 15
PERCENT THOUGH MAX HUMIDITIES REMAIN FAIR. NO STRONG WINDS ARE
EXPECTED DURING THIS TIME FRAME. ON FRIDAY...A PACIFIC WEATHER
SYSTEM WILL PULL MOISTURE NORTHWARD OVER THE REGION FOR A RETURN OF
STORM CHANCES INTO NEXT WEEKEND...MAINLY EAST OF THE LOWER COLORADO
RIVER VALLEY. IN ADDITION...COOLER TEMPERATURES...HIGHER
HUMIDITIES...AND BREEZY TO LOCALLY WINDY CONDITIONS CAN BE EXPECTED
AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...DEWEY
PREVIOUS DISCUSSION...KUHLMAN
AVIATION...AJ
FIRE WEATHER...AJ









000
FXUS65 KPSR 211610 AAA
AFDPSR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PHOENIX AZ
910 AM MST SUN SEP 21 2014

.SYNOPSIS...
DRIER AIR WILL GRADUALLY FILTER INTO THE REGION TODAY AND MONDAY
LEADING TO DRASTIC DECLINE IN STORM CHANCES. SLIGHT CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE HIGHER MOUNTAINS
OF SOUTH-CENTRAL ARIZONA THROUGH MONDAY. SLIGHTLY ABOVE NORMAL
TEMPERATURES ARE ANTICIPATED THROUGH THE MIDDLE OF THIS WEEK. AN
APPROACHING PACIFIC WEATHER SYSTEM LIKELY AFFECTING THE DESERT
SOUTHWEST ON FRIDAY AND SATURDAY WILL LEAD TO AN INCREASE IN STORM
CHANCES AND COOLER TEMPERATURES.

&&

.DISCUSSION...
THE UPPER LEVEL CUT OFF LOW IS CENTERED JUST TO THE EAST OF LAKE
TAHOE IN WESTERN NEVADA THIS MORNING PER WATER VAPOR AND IR
SATELLITE IMAGERY. A LARGE AREA OF CLOUD COVER AND SHOWER AND STORM
ACTIVITY IS QUICKLY MOVING NORTHWARD THROUGH NORTHERN
ARIZONA...SOUTHERN NEVADA AND SOUTHERN UTAH AS OF 1545Z THIS
MORNING. PER THE 12Z RAOB FOR KFGZ A VERY MOIST AND SATURATED COLUMN
OF AIR WITH FAIRLY STRONG SOUTHERLY STEERING FLOW...AND AS SUCH FOR
KTWC WITH LITTLE CHANGE TO THE MOISTURE PROFILE KEEPING 1.5 INCH
PWAT AND A MODERATE LOWER LEVEL STEERING FLOW PATTERN. AT KPSR
HOWEVER...A DRASTIC DROP IN MOISTURE WITH PWAT VALUES LOSING OVER
HALF AN INCH COMING IT AT 1.15 INCH. IN CONJUNCTION WITH A DRYING
TREND...MOST AREAS ACROSS THE DESERTS THIS MORNING ARE SEEING
DEWPOINT VALUES SLOWLY COME DOWN TO THE LOWER 60S AND LOWER 50S
UNDER PARTLY CLOUDY SKIES.

WITH THE PROGRESSION OF THE UPPER LEVEL DISTURBANCE TODAY...EXPECT
MOST CONVECTIVE AND SHOWER ACTIVITY WILL REMAIN IN THE EASTERN AND
SOUTHEASTERN HALF OF THE STATE TODAY...WHERE THE BEST DYNAMIC SET UP
WILL REMAIN. ONLY MADE A FEW MINOR UPDATES TO THE FORECAST THIS
MORNING FOR CURRENT TRENDS.

.PREVIOUS DISCUSSION.../ISSUED 217 AM MST/PDT 21 SEPT/...
AS THE UPPER LOW WHICH IS NOW CENTERED OVER CENTRAL CALIFORNIA
CONTINUES TO LIFT NORTHWARD...DRIER SOUTHWESTERLY MID AND UPPER
LEVEL FLOW IS TAKING OVER ACROSS SOUTHWEST AND MUCH OF SOUTH-CENTRAL
ARIZONA. THIS DRIER AIR IS EXPECTED TO PUSH AS FAR EAST AS PHOENIX
BY THIS AFTERNOON...ESSENTIALLY CUTTING OFF ANY RAIN CHANCES EXCEPT
FOR HIGHER TERRAIN AREAS EAST OF PHOENIX. THE UPPER LOW IS FORECAST
TO MOVE INTO THE GREAT BASIN BY THIS EVENING WITH THE UPPER RIDGE TO
OUR SOUTH CREEPING NORTHWARD INTO ARIZONA. GOOD MODEL AGREEMENT
SHOWS THE RIDGE BUILDING OVER THE DESERT SOUTHWEST THE NEXT FEW DAYS
WITH HEIGHTS MAXING OUT IN THE 590-592DM RANGE ON TUESDAY AND
WEDNESDAY. ANY LINGERING LOW LEVEL MOISTURE OVER EAST-CENTRAL
ARIZONA WILL LIKELY GET PUSHED OUT OF THE AREA WHICH SHOULD END ANY
SLIGHT CHANCES FOR RAIN ACROSS THE HIGHER TERRAIN ON TUESDAY AND
WEDNESDAY. THE HIGH HEIGHTS AND DRIER AIR WILL ALLOW FOR SOME
WARMING OVER THE NEXT FEW DAYS WITH LOWER DESERT LOCATIONS PEAKING
OUT IN THE 100-105 RANGE...OR ROUGHLY 3-5 DEGREES ABOVE SEASONAL
NORMALS.

BY LATE IN THE WEEK...THE NEXT WEATHER SYSTEM WILL SLOWLY MOVE
SOUTHEASTWARD INTO THE PACIFIC NORTHWEST AND GREAT BASIN. A GOOD
AMOUNT OF UNCERTAINTY REMAINS WITH THIS SYSTEM WITH LONG RANGE
MODELS STRUGGLING A BIT WITH THE TIMING AND HOW FAR SOUTH THE MAIN
SHORTWAVE WILL GO. LATEST RUNS SHOW A FASTER AND LESS DIGGING TROUGH
FROM THE GFS WHILE THE EUROPEAN DIGS THE TROUGH AS FAR SOUTH AS
SOUTHERN CALIFORNIA WHILE BRIEFLY CUTTING THE LOW OFF FROM THE POLAR
JET STREAM. THE TIMING DOES SEEM TO BE PUSHED BACK FROM YESTERDAY/S
MODEL RUNS...SO THE BEST RAIN CHANCES HAVE SHIFTED FROM FRIDAY TO
SATURDAY. THIS IS REFLECTED IN THE FORECAST BY DECREASING POPS
SLIGHTLY ON FRIDAY AND INCREASING POPS ON SATURDAY. THE AMOUNT OF
MOISTURE THAT WILL GET DRAWN UP AHEAD OF THE SYSTEM IS ALSO
PROBLEMATIC AS THE DEEPER EUROPEAN BRINGS IN SUBSTANTIALLY MORE
MOISTURE THAN THE GFS. FOR NOW...KEEPING WITH A FAIRLY WIDESPREAD
10-20 POPS ON BOTH DAYS. TEMPERATURES WILL BEGIN TO DECREASE
STARTING FRIDAY WITH LOWER DESERT HIGHS LIKELY ONLY IN THE LOWER 90S
FOR NEXT WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL AND SOUTHWEST ARIZONA INCLUDING KPHX...KIWA...KSDL...
STORM CHANCES OVER SOUTHERN ARIZONA TODAY WILL BE EAST OF A LINE
FROM WICKENBURG TO SELLS WITH ONLY SLIGHT CHANCES OVER PHOENIX
METRO. THUS HELD OFF ON INSERTING TEMPO SHWRS/TSTMS IN TAFS.
OUTFLOWS FROM DISTANT STORMS MAY LEAD TO WIND SHIFTS LATER
TODAY...BUT LESS LIKELY THAN YESTERDAY. ANTICIPATE SLOWER ARRIVAL OF
WESTERLY WINDS AT KPHX TODAY THAN YESTERDAY.

SOUTHEAST CALIFORNIA INCLUDING KIPL...AND KBLH...
SOUTH AND SOUTHEASTERLY WINDS WILL BE FAVORED ONCE AGAIN...LESS SO
OVER IMPERIAL VALLEY WITH WESTERLY FAVORED. OTHERWISE CLEAR SKIES.


AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
MOISTURE RETREAT DUE TO WESTERLY FLOW WILL KEEP STORM CHANCES
MINIMAL THROUGH THURSDAY AND LIMITED TO THE HIGHER MOUNTAINS OF
SOUTH-CENTRAL ARIZONA. MEANWHILE...TEMPERATURES NUDGE UPWARD A FEW
DEGREES ABOVE NORMAL. HUMIDITIES ON THE LOWER DESERTS DROP BELOW 15
PERCENT THOUGH MAX HUMIDITIES REMAIN FAIR. NO STRONG WINDS ARE
EXPECTED DURING THIS TIME FRAME. ON FRIDAY...A PACIFIC WEATHER
SYSTEM WILL PULL MOISTURE NORTHWARD OVER THE REGION FOR A RETURN OF
STORM CHANCES INTO NEXT WEEKEND...MAINLY EAST OF THE LOWER COLORADO
RIVER VALLEY. IN ADDITION...COOLER TEMPERATURES...HIGHER
HUMIDITIES...AND BREEZY TO LOCALLY WINDY CONDITIONS CAN BE EXPECTED
AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...DEWEY
PREVIOUS DISCUSSION...KUHLMAN
AVIATION...AJ
FIRE WEATHER...AJ








000
FXUS65 KPSR 211218 AAA
AFDPSR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PHOENIX AZ
520 AM MST SUN SEP 21 2014

.UPDATE...
UPDATED AVIATION AND FIRE WEATHER SECTIONS.

&&

.SYNOPSIS...
DRIER AIR WILL GRADUALLY FILTER INTO THE REGION TODAY AND MONDAY
LEADING TO DRASTIC DECLINE IN STORM CHANCES. SLIGHT CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE HIGHER MOUNTAINS
OF SOUTH-CENTRAL ARIZONA THROUGH MONDAY. SLIGHTLY ABOVE NORMAL
TEMPERATURES ARE ANTICIPATED THROUGH THE MIDDLE OF THIS WEEK. AN
APPROACHING PACIFIC WEATHER SYSTEM LIKELY AFFECTING THE DESERT
SOUTHWEST ON FRIDAY AND SATURDAY WILL LEAD TO AN INCREASE IN STORM
CHANCES AND COOLER TEMPERATURES.

&&

.DISCUSSION...
AS THE UPPER LOW WHICH IS NOW CENTERED OVER CENTRAL CALIFORNIA
CONTINUES TO LIFT NORTHWARD...DRIER SOUTHWESTERLY MID AND UPPER
LEVEL FLOW IS TAKING OVER ACROSS SOUTHWEST AND MUCH OF SOUTH-CENTRAL
ARIZONA. THIS DRIER AIR IS EXPECTED TO PUSH AS FAR EAST AS PHOENIX
BY THIS AFTERNOON...ESSENTIALLY CUTTING OFF ANY RAIN CHANCES EXCEPT
FOR HIGHER TERRAIN AREAS EAST OF PHOENIX. THE UPPER LOW IS FORECAST
TO MOVE INTO THE GREAT BASIN BY THIS EVENING WITH THE UPPER RIDGE TO
OUR SOUTH CREEPING NORTHWARD INTO ARIZONA. GOOD MODEL AGREEMENT
SHOWS THE RIDGE BUILDING OVER THE DESERT SOUTHWEST THE NEXT FEW DAYS
WITH HEIGHTS MAXING OUT IN THE 590-592DM RANGE ON TUESDAY AND
WEDNESDAY. ANY LINGERING LOW LEVEL MOISTURE OVER EAST-CENTRAL
ARIZONA WILL LIKELY GET PUSHED OUT OF THE AREA WHICH SHOULD END ANY
SLIGHT CHANCES FOR RAIN ACROSS THE HIGHER TERRAIN ON TUESDAY AND
WEDNESDAY. THE HIGH HEIGHTS AND DRIER AIR WILL ALLOW FOR SOME
WARMING OVER THE NEXT FEW DAYS WITH LOWER DESERT LOCATIONS PEAKING
OUT IN THE 100-105 RANGE...OR ROUGHLY 3-5 DEGREES ABOVE SEASONAL
NORMALS.

BY LATE IN THE WEEK...THE NEXT WEATHER SYSTEM WILL SLOWLY MOVE
SOUTHEASTWARD INTO THE PACIFIC NORTHWEST AND GREAT BASIN. A GOOD
AMOUNT OF UNCERTAINTY REMAINS WITH THIS SYSTEM WITH LONG RANGE
MODELS STRUGGLING A BIT WITH THE TIMING AND HOW FAR SOUTH THE MAIN
SHORTWAVE WILL GO. LATEST RUNS SHOW A FASTER AND LESS DIGGING TROUGH
FROM THE GFS WHILE THE EUROPEAN DIGS THE TROUGH AS FAR SOUTH AS
SOUTHERN CALIFORNIA WHILE BRIEFLY CUTTING THE LOW OFF FROM THE POLAR
JET STREAM. THE TIMING DOES SEEM TO BE PUSHED BACK FROM YESTERDAY/S
MODEL RUNS...SO THE BEST RAIN CHANCES HAVE SHIFTED FROM FRIDAY TO
SATURDAY. THIS IS REFLECTED IN THE FORECAST BY DECREASING POPS
SLIGHTLY ON FRIDAY AND INCREASING POPS ON SATURDAY. THE AMOUNT OF
MOISTURE THAT WILL GET DRAWN UP AHEAD OF THE SYSTEM IS ALSO
PROBLEMATIC AS THE DEEPER EUROPEAN BRINGS IN SUBSTANTIALLY MORE
MOISTURE THAN THE GFS. FOR NOW...KEEPING WITH A FAIRLY WIDESPREAD
10-20 POPS ON BOTH DAYS. TEMPERATURES WILL BEGIN TO DECREASE
STARTING FRIDAY WITH LOWER DESERT HIGHS LIKELY ONLY IN THE LOWER 90S
FOR NEXT WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL AND SOUTHWEST ARIZONA INCLUDING KPHX...KIWA...KSDL...
STORM CHANCES OVER SOUTHERN ARIZONA TODAY WILL BE EAST OF A LINE
FROM WICKENBURG TO SELLS WITH ONLY SLIGHT CHANCES OVER PHOENIX
METRO. THUS HELD OFF ON INSERTING TEMPO SHWRS/TSTMS IN TAFS.
OUTFLOWS FROM DISTANT STORMS MAY LEAD TO WIND SHIFTS LATER
TODAY...BUT LESS LIKELY THAN YESTERDAY. ANTICIPATE SLOWER ARRIVAL OF
WESTERLY WINDS AT KPHX TODAY THAN YESTERDAY.

SOUTHEAST CALIFORNIA INCLUDING KIPL...AND KBLH...
SOUTH AND SOUTHEASTERLY WINDS WILL BE FAVORED ONCE AGAIN...LESS SO
OVER IMPERIAL VALLEY WITH WESTERLY FAVORED. OTHERWISE CLEAR SKIES.


AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
MOISTURE RETREAT DUE TO WESTERLY FLOW WILL KEEP STORM CHANCES
MINIMAL THROUGH THURSDAY AND LIMITED TO THE HIGHER MOUNTAINS OF
SOUTH-CENTRAL ARIZONA. MEANWHILE...TEMPERATURES NUDGE UPWARD A FEW
DEGREES ABOVE NORMAL. HUMIDITIES ON THE LOWER DESERTS DROP BELOW 15
PERCENT THOUGH MAX HUMIDITIES REMAIN FAIR. NO STRONG WINDS ARE
EXPECTED DURING THIS TIME FRAME. ON FRIDAY...A PACIFIC WEATHER
SYSTEM WILL PULL MOISTURE NORTHWARD OVER THE REGION FOR A RETURN OF
STORM CHANCES INTO NEXT WEEKEND...MAINLY EAST OF THE LOWER COLORADO
RIVER VALLEY. IN ADDITION...COOLER TEMPERATURES...HIGHER
HUMIDITIES...AND BREEZY TO LOCALLY WINDY CONDITIONS CAN BE EXPECTED
AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...KUHLMAN
AVIATION...AJ
FIRE WEATHER...AJ
















000
FXUS65 KPSR 211218 AAA
AFDPSR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PHOENIX AZ
520 AM MST SUN SEP 21 2014

.UPDATE...
UPDATED AVIATION AND FIRE WEATHER SECTIONS.

&&

.SYNOPSIS...
DRIER AIR WILL GRADUALLY FILTER INTO THE REGION TODAY AND MONDAY
LEADING TO DRASTIC DECLINE IN STORM CHANCES. SLIGHT CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE HIGHER MOUNTAINS
OF SOUTH-CENTRAL ARIZONA THROUGH MONDAY. SLIGHTLY ABOVE NORMAL
TEMPERATURES ARE ANTICIPATED THROUGH THE MIDDLE OF THIS WEEK. AN
APPROACHING PACIFIC WEATHER SYSTEM LIKELY AFFECTING THE DESERT
SOUTHWEST ON FRIDAY AND SATURDAY WILL LEAD TO AN INCREASE IN STORM
CHANCES AND COOLER TEMPERATURES.

&&

.DISCUSSION...
AS THE UPPER LOW WHICH IS NOW CENTERED OVER CENTRAL CALIFORNIA
CONTINUES TO LIFT NORTHWARD...DRIER SOUTHWESTERLY MID AND UPPER
LEVEL FLOW IS TAKING OVER ACROSS SOUTHWEST AND MUCH OF SOUTH-CENTRAL
ARIZONA. THIS DRIER AIR IS EXPECTED TO PUSH AS FAR EAST AS PHOENIX
BY THIS AFTERNOON...ESSENTIALLY CUTTING OFF ANY RAIN CHANCES EXCEPT
FOR HIGHER TERRAIN AREAS EAST OF PHOENIX. THE UPPER LOW IS FORECAST
TO MOVE INTO THE GREAT BASIN BY THIS EVENING WITH THE UPPER RIDGE TO
OUR SOUTH CREEPING NORTHWARD INTO ARIZONA. GOOD MODEL AGREEMENT
SHOWS THE RIDGE BUILDING OVER THE DESERT SOUTHWEST THE NEXT FEW DAYS
WITH HEIGHTS MAXING OUT IN THE 590-592DM RANGE ON TUESDAY AND
WEDNESDAY. ANY LINGERING LOW LEVEL MOISTURE OVER EAST-CENTRAL
ARIZONA WILL LIKELY GET PUSHED OUT OF THE AREA WHICH SHOULD END ANY
SLIGHT CHANCES FOR RAIN ACROSS THE HIGHER TERRAIN ON TUESDAY AND
WEDNESDAY. THE HIGH HEIGHTS AND DRIER AIR WILL ALLOW FOR SOME
WARMING OVER THE NEXT FEW DAYS WITH LOWER DESERT LOCATIONS PEAKING
OUT IN THE 100-105 RANGE...OR ROUGHLY 3-5 DEGREES ABOVE SEASONAL
NORMALS.

BY LATE IN THE WEEK...THE NEXT WEATHER SYSTEM WILL SLOWLY MOVE
SOUTHEASTWARD INTO THE PACIFIC NORTHWEST AND GREAT BASIN. A GOOD
AMOUNT OF UNCERTAINTY REMAINS WITH THIS SYSTEM WITH LONG RANGE
MODELS STRUGGLING A BIT WITH THE TIMING AND HOW FAR SOUTH THE MAIN
SHORTWAVE WILL GO. LATEST RUNS SHOW A FASTER AND LESS DIGGING TROUGH
FROM THE GFS WHILE THE EUROPEAN DIGS THE TROUGH AS FAR SOUTH AS
SOUTHERN CALIFORNIA WHILE BRIEFLY CUTTING THE LOW OFF FROM THE POLAR
JET STREAM. THE TIMING DOES SEEM TO BE PUSHED BACK FROM YESTERDAY/S
MODEL RUNS...SO THE BEST RAIN CHANCES HAVE SHIFTED FROM FRIDAY TO
SATURDAY. THIS IS REFLECTED IN THE FORECAST BY DECREASING POPS
SLIGHTLY ON FRIDAY AND INCREASING POPS ON SATURDAY. THE AMOUNT OF
MOISTURE THAT WILL GET DRAWN UP AHEAD OF THE SYSTEM IS ALSO
PROBLEMATIC AS THE DEEPER EUROPEAN BRINGS IN SUBSTANTIALLY MORE
MOISTURE THAN THE GFS. FOR NOW...KEEPING WITH A FAIRLY WIDESPREAD
10-20 POPS ON BOTH DAYS. TEMPERATURES WILL BEGIN TO DECREASE
STARTING FRIDAY WITH LOWER DESERT HIGHS LIKELY ONLY IN THE LOWER 90S
FOR NEXT WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL AND SOUTHWEST ARIZONA INCLUDING KPHX...KIWA...KSDL...
STORM CHANCES OVER SOUTHERN ARIZONA TODAY WILL BE EAST OF A LINE
FROM WICKENBURG TO SELLS WITH ONLY SLIGHT CHANCES OVER PHOENIX
METRO. THUS HELD OFF ON INSERTING TEMPO SHWRS/TSTMS IN TAFS.
OUTFLOWS FROM DISTANT STORMS MAY LEAD TO WIND SHIFTS LATER
TODAY...BUT LESS LIKELY THAN YESTERDAY. ANTICIPATE SLOWER ARRIVAL OF
WESTERLY WINDS AT KPHX TODAY THAN YESTERDAY.

SOUTHEAST CALIFORNIA INCLUDING KIPL...AND KBLH...
SOUTH AND SOUTHEASTERLY WINDS WILL BE FAVORED ONCE AGAIN...LESS SO
OVER IMPERIAL VALLEY WITH WESTERLY FAVORED. OTHERWISE CLEAR SKIES.


AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
MOISTURE RETREAT DUE TO WESTERLY FLOW WILL KEEP STORM CHANCES
MINIMAL THROUGH THURSDAY AND LIMITED TO THE HIGHER MOUNTAINS OF
SOUTH-CENTRAL ARIZONA. MEANWHILE...TEMPERATURES NUDGE UPWARD A FEW
DEGREES ABOVE NORMAL. HUMIDITIES ON THE LOWER DESERTS DROP BELOW 15
PERCENT THOUGH MAX HUMIDITIES REMAIN FAIR. NO STRONG WINDS ARE
EXPECTED DURING THIS TIME FRAME. ON FRIDAY...A PACIFIC WEATHER
SYSTEM WILL PULL MOISTURE NORTHWARD OVER THE REGION FOR A RETURN OF
STORM CHANCES INTO NEXT WEEKEND...MAINLY EAST OF THE LOWER COLORADO
RIVER VALLEY. IN ADDITION...COOLER TEMPERATURES...HIGHER
HUMIDITIES...AND BREEZY TO LOCALLY WINDY CONDITIONS CAN BE EXPECTED
AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...KUHLMAN
AVIATION...AJ
FIRE WEATHER...AJ















000
FXUS65 KPSR 210917
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
217 AM MST SUN SEP 21 2014

.SYNOPSIS...
DRIER AIR WILL GRADUALLY FILTER INTO THE REGION TODAY AND MONDAY
LEADING TO DRASTIC DECLINE IN STORM CHANCES. SLIGHT CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE HIGHER MOUNTAINS
OF SOUTH-CENTRAL ARIZONA THROUGH MONDAY. SLIGHTLY ABOVE NORMAL
TEMPERATURES ARE ANTICIPATED THROUGH THE MIDDLE OF THIS WEEK. AN
APPROACHING PACIFIC WEATHER SYSTEM LIKELY AFFECTING THE DESERT
SOUTHWEST ON FRIDAY AND SATURDAY WILL LEAD TO AN INCREASE IN STORM
CHANCES AND COOLER TEMPERATURES.

&&

.DISCUSSION...
AS THE UPPER LOW WHICH IS NOW CENTERED OVER CENTRAL CALIFORNIA
CONTINUES TO LIFT NORTHWARD...DRIER SOUTHWESTERLY MID AND UPPER
LEVEL FLOW IS TAKING OVER ACROSS SOUTHWEST AND MUCH OF SOUTH-CENTRAL
ARIZONA. THIS DRIER AIR IS EXPECTED TO PUSH AS FAR EAST AS PHOENIX
BY THIS AFTERNOON...ESSENTIALLY CUTTING OFF ANY RAIN CHANCES EXCEPT
FOR HIGHER TERRAIN AREAS EAST OF PHOENIX. THE UPPER LOW IS FORECAST
TO MOVE INTO THE GREAT BASIN BY THIS EVENING WITH THE UPPER RIDGE TO
OUR SOUTH CREEPING NORTHWARD INTO ARIZONA. GOOD MODEL AGREEMENT
SHOWS THE RIDGE BUILDING OVER THE DESERT SOUTHWEST THE NEXT FEW DAYS
WITH HEIGHTS MAXING OUT IN THE 590-592DM RANGE ON TUESDAY AND
WEDNESDAY. ANY LINGERING LOW LEVEL MOISTURE OVER EAST-CENTRAL
ARIZONA WILL LIKELY GET PUSHED OUT OF THE AREA WHICH SHOULD END ANY
SLIGHT CHANCES FOR RAIN ACROSS THE HIGHER TERRAIN ON TUESDAY AND
WEDNESDAY. THE HIGH HEIGHTS AND DRIER AIR WILL ALLOW FOR SOME
WARMING OVER THE NEXT FEW DAYS WITH LOWER DESERT LOCATIONS PEAKING
OUT IN THE 100-105 RANGE...OR ROUGHLY 3-5 DEGREES ABOVE SEASONAL
NORMALS.

BY LATE IN THE WEEK...THE NEXT WEATHER SYSTEM WILL SLOWLY MOVE
SOUTHEASTWARD INTO THE PACIFIC NORTHWEST AND GREAT BASIN. A GOOD
AMOUNT OF UNCERTAINTY REMAINS WITH THIS SYSTEM WITH LONG RANGE
MODELS STRUGGLING A BIT WITH THE TIMING AND HOW FAR SOUTH THE MAIN
SHORTWAVE WILL GO. LATEST RUNS SHOW A FASTER AND LESS DIGGING TROUGH
FROM THE GFS WHILE THE EUROPEAN DIGS THE TROUGH AS FAR SOUTH AS
SOUTHERN CALIFORNIA WHILE BRIEFLY CUTTING THE LOW OFF FROM THE POLAR
JET STREAM. THE TIMING DOES SEEM TO BE PUSHED BACK FROM YESTERDAY/S
MODEL RUNS...SO THE BEST RAIN CHANCES HAVE SHIFTED FROM FRIDAY TO
SATURDAY. THIS IS REFLECTED IN THE FORECAST BY DECREASING POPS
SLIGHTLY ON FRIDAY AND INCREASING POPS ON SATURDAY. THE AMOUNT OF
MOISTURE THAT WILL GET DRAWN UP AHEAD OF THE SYSTEM IS ALSO
PROBLEMATIC AS THE DEEPER EUROPEAN BRINGS IN SUBSTANTIALLY MORE
MOISTURE THAN THE GFS. FOR NOW...KEEPING WITH A FAIRLY WIDESPREAD
10-20 POPS ON BOTH DAYS. TEMPERATURES WILL BEGIN TO DECREASE
STARTING FRIDAY WITH LOWER DESERT HIGHS LIKELY ONLY IN THE LOWER 90S
FOR NEXT WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL AND SOUTHWEST ARIZONA INCLUDING KPHX...KIWA...KSDL...
CONVECTIVE CHANCES OVER THE GREATER PHOENIX AREA HAVE ENDED. SCT-BKN
CLDS AOA 10 THSD AGL ARE EXPECTED THROUGH 08Z SUN...ALONG WITH LIGHT
WIND UNDER 8 KNOTS.  FROM 08Z SUN TO 21Z SUN...MOSTLY CLEAR SKIES
AND LIGHT WIND.

SOUTHEAST CALIFORNIA INCLUDING KIPL...AND KBLH...
THROUGH 21Z SUN...MOSTLY CLEAR SKIES AND LIGHT WIND.


AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
MOISTURE RETREAT DUE TO WESTERLY FLOW WILL KEEP STORM CHANCES
MINIMAL THROUGH THURSDAY AND LIMITED TO THE HIGHER MOUNTAINS OF
SOUTH-CENTRAL ARIZONA. MEANWHILE...TEMPERATURES NUDGE UPWARD A FEW
DEGREES ABOVE NORMAL. HUMIDITIES ON THE LOWER DESERTS DROP BELOW 15
PERCENT THOUGH MAX HUMIDITIES REMAIN FAIR. NO STRONG WINDS ARE
EXPECTED DURING THIS TIME FRAME. ON FRIDAY...A PACIFIC WEATHER
SYSTEM WILL PULL MOISTURE NORTHWARD OVER THE REGION FOR A RETURN OF
STORM CHANCES INTO NEXT WEEKEND...MAINLY EAST OF THE LOWER COLORADO
RIVER VALLEY. IN ADDITION...COOLER TEMPERATURES AND BREEZY TO
LOCALLY WINDY CONDITIONS CAN BE EXPECTED AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...KUHLMAN
AVIATION...VASQUEZ
FIRE WEATHER...MEYERS/AJ













000
FXUS65 KPSR 210917
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
217 AM MST SUN SEP 21 2014

.SYNOPSIS...
DRIER AIR WILL GRADUALLY FILTER INTO THE REGION TODAY AND MONDAY
LEADING TO DRASTIC DECLINE IN STORM CHANCES. SLIGHT CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE HIGHER MOUNTAINS
OF SOUTH-CENTRAL ARIZONA THROUGH MONDAY. SLIGHTLY ABOVE NORMAL
TEMPERATURES ARE ANTICIPATED THROUGH THE MIDDLE OF THIS WEEK. AN
APPROACHING PACIFIC WEATHER SYSTEM LIKELY AFFECTING THE DESERT
SOUTHWEST ON FRIDAY AND SATURDAY WILL LEAD TO AN INCREASE IN STORM
CHANCES AND COOLER TEMPERATURES.

&&

.DISCUSSION...
AS THE UPPER LOW WHICH IS NOW CENTERED OVER CENTRAL CALIFORNIA
CONTINUES TO LIFT NORTHWARD...DRIER SOUTHWESTERLY MID AND UPPER
LEVEL FLOW IS TAKING OVER ACROSS SOUTHWEST AND MUCH OF SOUTH-CENTRAL
ARIZONA. THIS DRIER AIR IS EXPECTED TO PUSH AS FAR EAST AS PHOENIX
BY THIS AFTERNOON...ESSENTIALLY CUTTING OFF ANY RAIN CHANCES EXCEPT
FOR HIGHER TERRAIN AREAS EAST OF PHOENIX. THE UPPER LOW IS FORECAST
TO MOVE INTO THE GREAT BASIN BY THIS EVENING WITH THE UPPER RIDGE TO
OUR SOUTH CREEPING NORTHWARD INTO ARIZONA. GOOD MODEL AGREEMENT
SHOWS THE RIDGE BUILDING OVER THE DESERT SOUTHWEST THE NEXT FEW DAYS
WITH HEIGHTS MAXING OUT IN THE 590-592DM RANGE ON TUESDAY AND
WEDNESDAY. ANY LINGERING LOW LEVEL MOISTURE OVER EAST-CENTRAL
ARIZONA WILL LIKELY GET PUSHED OUT OF THE AREA WHICH SHOULD END ANY
SLIGHT CHANCES FOR RAIN ACROSS THE HIGHER TERRAIN ON TUESDAY AND
WEDNESDAY. THE HIGH HEIGHTS AND DRIER AIR WILL ALLOW FOR SOME
WARMING OVER THE NEXT FEW DAYS WITH LOWER DESERT LOCATIONS PEAKING
OUT IN THE 100-105 RANGE...OR ROUGHLY 3-5 DEGREES ABOVE SEASONAL
NORMALS.

BY LATE IN THE WEEK...THE NEXT WEATHER SYSTEM WILL SLOWLY MOVE
SOUTHEASTWARD INTO THE PACIFIC NORTHWEST AND GREAT BASIN. A GOOD
AMOUNT OF UNCERTAINTY REMAINS WITH THIS SYSTEM WITH LONG RANGE
MODELS STRUGGLING A BIT WITH THE TIMING AND HOW FAR SOUTH THE MAIN
SHORTWAVE WILL GO. LATEST RUNS SHOW A FASTER AND LESS DIGGING TROUGH
FROM THE GFS WHILE THE EUROPEAN DIGS THE TROUGH AS FAR SOUTH AS
SOUTHERN CALIFORNIA WHILE BRIEFLY CUTTING THE LOW OFF FROM THE POLAR
JET STREAM. THE TIMING DOES SEEM TO BE PUSHED BACK FROM YESTERDAY/S
MODEL RUNS...SO THE BEST RAIN CHANCES HAVE SHIFTED FROM FRIDAY TO
SATURDAY. THIS IS REFLECTED IN THE FORECAST BY DECREASING POPS
SLIGHTLY ON FRIDAY AND INCREASING POPS ON SATURDAY. THE AMOUNT OF
MOISTURE THAT WILL GET DRAWN UP AHEAD OF THE SYSTEM IS ALSO
PROBLEMATIC AS THE DEEPER EUROPEAN BRINGS IN SUBSTANTIALLY MORE
MOISTURE THAN THE GFS. FOR NOW...KEEPING WITH A FAIRLY WIDESPREAD
10-20 POPS ON BOTH DAYS. TEMPERATURES WILL BEGIN TO DECREASE
STARTING FRIDAY WITH LOWER DESERT HIGHS LIKELY ONLY IN THE LOWER 90S
FOR NEXT WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL AND SOUTHWEST ARIZONA INCLUDING KPHX...KIWA...KSDL...
CONVECTIVE CHANCES OVER THE GREATER PHOENIX AREA HAVE ENDED. SCT-BKN
CLDS AOA 10 THSD AGL ARE EXPECTED THROUGH 08Z SUN...ALONG WITH LIGHT
WIND UNDER 8 KNOTS.  FROM 08Z SUN TO 21Z SUN...MOSTLY CLEAR SKIES
AND LIGHT WIND.

SOUTHEAST CALIFORNIA INCLUDING KIPL...AND KBLH...
THROUGH 21Z SUN...MOSTLY CLEAR SKIES AND LIGHT WIND.


AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
MOISTURE RETREAT DUE TO WESTERLY FLOW WILL KEEP STORM CHANCES
MINIMAL THROUGH THURSDAY AND LIMITED TO THE HIGHER MOUNTAINS OF
SOUTH-CENTRAL ARIZONA. MEANWHILE...TEMPERATURES NUDGE UPWARD A FEW
DEGREES ABOVE NORMAL. HUMIDITIES ON THE LOWER DESERTS DROP BELOW 15
PERCENT THOUGH MAX HUMIDITIES REMAIN FAIR. NO STRONG WINDS ARE
EXPECTED DURING THIS TIME FRAME. ON FRIDAY...A PACIFIC WEATHER
SYSTEM WILL PULL MOISTURE NORTHWARD OVER THE REGION FOR A RETURN OF
STORM CHANCES INTO NEXT WEEKEND...MAINLY EAST OF THE LOWER COLORADO
RIVER VALLEY. IN ADDITION...COOLER TEMPERATURES AND BREEZY TO
LOCALLY WINDY CONDITIONS CAN BE EXPECTED AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...KUHLMAN
AVIATION...VASQUEZ
FIRE WEATHER...MEYERS/AJ












000
FXUS65 KPSR 210316
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
815 PM MST SAT SEP 20 2014

.SYNOPSIS...
LINGERING MOISTURE ACROSS THE REGION AND LOW PRESSURE APPROACHING
FROM THE WEST WILL KEEP AT LEAST SLIGHT CHANCES FOR SHOWERS AND
THUNDERSTORMS FOR TODAY. DRIER AIR WILL GRADUALLY FILTER
INTO THE REGION SUNDAY AND MONDAY FOR A DECLINE IN STORM CHANCES.
SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE
HIGHER MOUNTAINS OF SOUTH-CENTRAL ARIZONA DURING THE MIDDLE OF NEXT
WEEK WITH SLIGHTLY ABOVE NORMAL TEMPERATURES. AN APPROACHING
PACIFIC WEATHER SYSTEM LATE NEXT WEEK WILL LEAD TO AN INCREASE IN
STORM CHANCES.

&&

.DISCUSSION...
A VERY VIGOROUS PACIFIC SHORTWAVE THAT MOVED INTO CENTRAL AND
SOUTHERN CA SATURDAY PROVIDED WEAK UPPER LEVEL SUPPORT ACROSS
CENTRAL AZ FOR A FEW STRONG HEAT OF THE DAY THUNDERSTORMS NEAR
PHOENIX GIVEN THE RICH MOISTURE SUPPLY. FOR THE REMAINDER OF THE
EVENING ONLY A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS CAN BE
EXPECTED THROUGH MIDNIGHT IN THE ABSENCE OF SURFACE HEATING AND
OUTFLOW BOUNDARIES. CLEARING SKIES ARE EXPECTED AFTER MIDNIGHT
ACROSS THE ENTIRE FORECAST AREA.

AS THE PACIFIC TROF MOVES FARTHER NORTH AND AWAY FROM AZ...INTO
CENTRAL NEVADA...A MORE DYNAMICALLY STABLE ATMOSPHERE IS EXPECTED
SUNDAY AFTERNOON AND EVENING. A THINNING OF BOUNDARY LAYER MOISTURE
IS ALSO EXPECTED FROM THE WEST. ONLY A SLIGHT CHANCE OF THUNDER-
STORMS ARE FORECAST OVER THE MOUNTAINS OF SOUTHERN GILA COUNTY ZONE
24 EAST OF PHOENIX ON SUNDAY.

UPDATES WERE MADE TO DIMINISH THE CHANCE OF SHWR/TSTM ACTIVITY OVER
SOUTH CENTRAL AZ THE REMAINDER OF THE EVENING. OTHERWISE...NO
ADDITIONAL UPDATES ARE EXPECTED. PREVIOUS DISCUSSION STILL APPLIES.


.PREVIOUS DISCUSSION...340 PM MST...
PRECIPITABLE WATER VALUES HOVERING AROUND 1.5 INCHES ACROSS THE
LOWER DESERTS AND A VERY BROAD DIFLUENT MID-LAYER STRETCHING
NORTH-NORTHWEST THROUGH THE GREAT BASIN ALLOWED FOR CONVECTIVE
DEVELOPMENT IN SOUTH CENTRAL AZ SATURDAY AFTERNOON.

STORM CHANCES WILL BE ON THE DECLINE THROUGH MONDAY BEFORE COMING TO
A QUIET HOLDING PATTERN THROUGH THE WEEK. MONSOON MOISTURE LOOKS TO
HANG AROUND THIS WEEK BUT MAINLY ACROSS EASTERN ARIZONA. THE UPPER
LEVEL DISTURBANCE IS PROGGED TO MOVE NORTH THROUGH THE GREAT BASIN
BY MONDAY AND WILL ALLOW A WESTERLY FLOW TO SETTLE IN PLACE OVER THE
SOUTHWEST DESERTS AS WELL AS A DRYING TREND. WILL KEEP SLIGHT CHANCE
MENTION IN ZONE 24 FOR THE HIGHER TERRAIN LOCATIONS. TEMPERATURES
WILL HAVE LITTLE DAY TO DAY CHANGE...REMAINING AT OR A FEW DEGREES
ABOVE SEASONAL NORMAL WITH HIGH PRESSURE DOMINATING THE REGION
THROUGH MID WEEK.

THURSDAY THROUGH SATURDAY...ATTENTION THEN TURNS TO A POSSIBLE
SEASONAL TRANSITION SYSTEM FOR LATE WEEK INTO NEXT WEEKEND.
CONFIDENCE IS STILL NOT VERY HIGH ON THE SPECIFICS OF THE SYSTEM BUT
THE 00Z OPERATIONAL MODELS HAVE COME IN CLOSER AGREEMENT THAT A DEEP
PACIFIC TROUGH WILL SLIDE THROUGH CALIFORNIA ON FRIDAY AND POSSIBLY
AS FAR SOUTH AS ARIZONA SOMETIME NEXT WEEKEND. WIDESPREAD SLIGHT
CHANCE POPS ARE IN THE FORECAST FOR FRIDAY. EITHER WAY IT IS FAIRLY
LIKELY THIS LOW WILL USER IN COOLER AND MUCH DRIER AIR...AND
POTENTIALLY END OUR MONSOON SEASON.

&&

.AVIATION...
SOUTH-CENTRAL AND SOUTHWEST ARIZONA INCLUDING KPHX...KIWA...KSDL...
CONVECTIVE CHANCES OVER THE GREATER PHOENIX AREA HAVE ENDED. SCT-BKN
CLDS AOA 10 THSD AGL ARE EXPECTED THROUGH 08Z SUN...ALONG WITH LIGHT
WIND UNDER 8 KNOTS.  FROM 08Z SUN TO 21Z SUN...MOSTLY CLEAR SKIES
AND LIGHT WIND.

SOUTHEAST CALIFORNIA INCLUDING KIPL...AND KBLH...
THROUGH 21Z SUN...MOSTLY CLEAR SKIES AND LIGHT WIND.


AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
MOISTURE RETREAT DUE TO WESTERLY FLOW WILL KEEP STORM CHANCES
MINIMAL THROUGH THURSDAY AND LIMITED TO THE HIGHER MOUNTAINS OF
SOUTH-CENTRAL ARIZONA. MEANWHILE...TEMPERATURES NUDGE UPWARD A FEW
DEGREES ABOVE NORMAL. HUMIDITIES ON THE LOWER DESERTS DROP BELOW 15
PERCENT THOUGH MAX HUMIDITIES REMAIN FAIR. NO STRONG WINDS ARE
EXPECTED DURING THIS TIME FRAME. ON FRIDAY...A PACIFIC WEATHER
SYSTEM WILL PULL MOISTURE NORTHWARD OVER THE REGION FOR A RETURN OF
STORM CHANCES INTO NEXT WEEKEND...MAINLY EAST OF THE LOWER COLORADO
RIVER VALLEY. IN ADDITION...COOLER TEMPERATURES AND BREEZY TO
LOCALLY WINDY CONDITIONS CAN BE EXPECTED AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...VASQUEZ/DEWEY
AVIATION...VASQUEZ
FIRE WEATHER...MEYERS/AJ









000
FXUS65 KPSR 202243 AAA
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
340 PM MST SAT SEP 20 2014

.UPDATE...UPDATED AVIATION AND FIRE WEATHER DISCUSSIONS.

&&


.SYNOPSIS...
LINGERING MOISTURE ACROSS THE REGION AND LOW PRESSURE APPROACHING
FROM THE WEST WILL KEEP AT LEAST SLIGHT CHANCES FOR SHOWERS AND
THUNDERSTORMS FOR TODAY. DRIER AIR WILL GRADUALLY FILTER
INTO THE REGION SUNDAY AND MONDAY FOR A DECLINE IN STORM CHANCES.
SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE
HIGHER MOUNTAINS OF SOUTH-CENTRAL ARIZONA DURING THE MIDDLE OF NEXT
WEEK WITH SLIGHTLY ABOVE NORMAL TEMPERATURES. AN APPROACHING
PACIFIC WEATHER SYSTEM LATE NEXT WEEK WILL LEAD TO AN INCREASE IN
STORM CHANCES.

&&

.DISCUSSION...
MODEL THETA-E GRADIENT ALIGNED WELL WITH THE FAVORABLE LOCATIONS OF
HIGHER MOISTURE CONTENT AND GREATER INSTABILITY. THE RAP MLCAPE
VALUES JUST OVER 1500 J/KG ALONG AN AXIS FROM NOGALES TO BULLHEAD
CITY. WESTERN MARICOPA COUNTY...LA PAZ AND NORTHERN YUMA COUNTIES
LOOK TO BE THE FAVORABLE AREAS FOR CONVECTION THIS AFTERNOON AND
EVENING. CAN NOT RULE OUT ISOLATED STORMS SNEAKING IN TO NORTHERN
PINAL COUNTY FROM SOUTH-CENTRAL ARIZONA...AS THE GREATER TUCSON AREA
HAS BEEN INCREASING IN ACTIVITY LATE THIS MORNING. PRECIPITABLE
WATER VALUES HOVERING AROUND 1.5 INCHES ACROSS THE LOWER DESERTS AND
A VERY BROAD DIFLUENT MID-LAYER STRETCHING NORTH-NORTHWEST THROUGH
THE GREAT BASIN ALLOWS FOR CONVECTIVE DEVELOPMENT THIS AFTERNOON AND
EVENING. MOISTURE AND DYNAMICS ARE IN PLACE AND THE POTENTIAL ENERGY
IS THERE...NOW THE CHALLENGE WILL BE FOR A TRIGGER TO PUSH THE
DEVELOPMENT NEEDED FOR THUNDERSTORM DEVELOPMENT.

STORM CHANCES WILL BE ON THE DECLINE THROUGH MONDAY BEFORE COMING TO
A QUIET HOLDING PATTERN THROUGH THE WEEK. MONSOON MOISTURE LOOKS TO
HANG AROUND THIS WEEK BUT MAINLY ACROSS EASTERN ARIZONA. THE UPPER
LEVEL DISTURBANCE IS PROGGED TO MOVE NORTH THROUGH THE GREAT BASIN
BY MONDAY AND WILL ALLOW A WESTERLY FLOW TO SETTLE IN PLACE OVER THE
SOUTHWEST DESERTS AS WELL AS A DRYING TREND. WILL KEEP SLIGHT CHANCE
MENTION IN ZONE 24 FOR THE HIGHER TERRAIN LOCATIONS. TEMPERATURES
WILL HAVE LITTLE DAY TO DAY CHANGE...REMAINING AT OR A FEW DEGREES
ABOVE SEASONAL NORMAL WITH HIGH PRESSURE DOMINATING THE REGION
THROUGH MID WEEK.

THURSDAY THROUGH SATURDAY...ATTENTION THEN TURNS TO A POSSIBLE
SEASONAL TRANSITION SYSTEM FOR LATE WEEK INTO NEXT WEEKEND.
CONFIDENCE IS STILL NOT VERY HIGH ON THE SPECIFICS OF THE SYSTEM BUT
THE 00Z OPERATIONAL MODELS HAVE COME IN CLOSER AGREEMENT THAT A DEEP
PACIFIC TROUGH WILL SLIDE THROUGH CALIFORNIA ON FRIDAY AND POSSIBLY
AS FAR SOUTH AS ARIZONA SOMETIME NEXT WEEKEND. WIDESPREAD SLIGHT
CHANCE POPS ARE IN THE FORECAST FOR FRIDAY. EITHER WAY IT IS FAIRLY
LIKELY THIS LOW WILL USER IN COOLER AND MUCH DRIER AIR...AND
POTENTIALLY END OUR MONSOON SEASON.

&&

.AVIATION...
SOUTH-CENTRAL AND SOUTHWEST ARIZONA INCLUDING KPHX...KIWA...KSDL...
ISOLATED TO WIDELY SCATTERED THUNDERSTORM ACTIVITY WILL PERSIST THIS
AFTERNOON AND EVENING OVER SOUTH-CENTRAL AZ...A FEW STORMS COULD
BRIEFLY IMPACT LOW DESERT TERMINALS WITH GUSTY OUTFLOWS UP TO 40
KT...AND REDUCED VISIBILITY DOWN TO 3SM IN BLDU. EXPECT SCT-BKN
CLOUD DECKS AOA 7000FT TO PERSIST OVERNIGHT TIMES INTO SUNDAY
MORNING. ONCE POTENTIAL FOR OUTFLOW BOUNDARIES DIMINISHES AFTER
04Z...WINDS WILL GENERALLY BE LIGHT...LESS THAN 10KT AND FAVOR THE
EAST SOUTHEAST AT ALL TERMINALS.

SOUTHEAST CALIFORNIA INCLUDING KIPL...AND KBLH...
OTHER THAN A FEW CLOUDS GENERALLY AOA 10KFT...EXPECT MOSTLY CLEAR
SKIES AND LIGHT WINDS OVERNIGHT THROUGH AT LEAST 18Z SUNDAY
AFTERNOON.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
MOISTURE RETREAT DUE TO WESTERLY FLOW WILL KEEP STORM CHANCES
MINIMAL THROUGH THURSDAY AND LIMITED TO THE HIGHER MOUNTAINS OF
SOUTH-CENTRAL ARIZONA. MEANWHILE...TEMPERATURES NUDGE UPWARD A FEW
DEGREES ABOVE NORMAL. HUMIDITIES ON THE LOWER DESERTS DROP BELOW 15
PERCENT THOUGH MAX HUMIDITIES REMAIN FAIR. NO STRONG WINDS ARE
EXPECTED DURING THIS TIME FRAME. ON FRIDAY...A PACIFIC WEATHER
SYSTEM WILL PULL MOISTURE NORTHWARD OVER THE REGION FOR A RETURN OF
STORM CHANCES INTO NEXT WEEKEND...MAINLY EAST OF THE LOWER COLORADO
RIVER VALLEY. IN ADDITION...COOLER TEMPERATURES AND BREEZY TO
LOCALLY WINDY CONDITIONS CAN BE EXPECTED AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

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







000
FXUS65 KPSR 202243 AAA
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
340 PM MST SAT SEP 20 2014

.UPDATE...UPDATED AVIATION AND FIRE WEATHER DISCUSSIONS.

&&


.SYNOPSIS...
LINGERING MOISTURE ACROSS THE REGION AND LOW PRESSURE APPROACHING
FROM THE WEST WILL KEEP AT LEAST SLIGHT CHANCES FOR SHOWERS AND
THUNDERSTORMS FOR TODAY. DRIER AIR WILL GRADUALLY FILTER
INTO THE REGION SUNDAY AND MONDAY FOR A DECLINE IN STORM CHANCES.
SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE
HIGHER MOUNTAINS OF SOUTH-CENTRAL ARIZONA DURING THE MIDDLE OF NEXT
WEEK WITH SLIGHTLY ABOVE NORMAL TEMPERATURES. AN APPROACHING
PACIFIC WEATHER SYSTEM LATE NEXT WEEK WILL LEAD TO AN INCREASE IN
STORM CHANCES.

&&

.DISCUSSION...
MODEL THETA-E GRADIENT ALIGNED WELL WITH THE FAVORABLE LOCATIONS OF
HIGHER MOISTURE CONTENT AND GREATER INSTABILITY. THE RAP MLCAPE
VALUES JUST OVER 1500 J/KG ALONG AN AXIS FROM NOGALES TO BULLHEAD
CITY. WESTERN MARICOPA COUNTY...LA PAZ AND NORTHERN YUMA COUNTIES
LOOK TO BE THE FAVORABLE AREAS FOR CONVECTION THIS AFTERNOON AND
EVENING. CAN NOT RULE OUT ISOLATED STORMS SNEAKING IN TO NORTHERN
PINAL COUNTY FROM SOUTH-CENTRAL ARIZONA...AS THE GREATER TUCSON AREA
HAS BEEN INCREASING IN ACTIVITY LATE THIS MORNING. PRECIPITABLE
WATER VALUES HOVERING AROUND 1.5 INCHES ACROSS THE LOWER DESERTS AND
A VERY BROAD DIFLUENT MID-LAYER STRETCHING NORTH-NORTHWEST THROUGH
THE GREAT BASIN ALLOWS FOR CONVECTIVE DEVELOPMENT THIS AFTERNOON AND
EVENING. MOISTURE AND DYNAMICS ARE IN PLACE AND THE POTENTIAL ENERGY
IS THERE...NOW THE CHALLENGE WILL BE FOR A TRIGGER TO PUSH THE
DEVELOPMENT NEEDED FOR THUNDERSTORM DEVELOPMENT.

STORM CHANCES WILL BE ON THE DECLINE THROUGH MONDAY BEFORE COMING TO
A QUIET HOLDING PATTERN THROUGH THE WEEK. MONSOON MOISTURE LOOKS TO
HANG AROUND THIS WEEK BUT MAINLY ACROSS EASTERN ARIZONA. THE UPPER
LEVEL DISTURBANCE IS PROGGED TO MOVE NORTH THROUGH THE GREAT BASIN
BY MONDAY AND WILL ALLOW A WESTERLY FLOW TO SETTLE IN PLACE OVER THE
SOUTHWEST DESERTS AS WELL AS A DRYING TREND. WILL KEEP SLIGHT CHANCE
MENTION IN ZONE 24 FOR THE HIGHER TERRAIN LOCATIONS. TEMPERATURES
WILL HAVE LITTLE DAY TO DAY CHANGE...REMAINING AT OR A FEW DEGREES
ABOVE SEASONAL NORMAL WITH HIGH PRESSURE DOMINATING THE REGION
THROUGH MID WEEK.

THURSDAY THROUGH SATURDAY...ATTENTION THEN TURNS TO A POSSIBLE
SEASONAL TRANSITION SYSTEM FOR LATE WEEK INTO NEXT WEEKEND.
CONFIDENCE IS STILL NOT VERY HIGH ON THE SPECIFICS OF THE SYSTEM BUT
THE 00Z OPERATIONAL MODELS HAVE COME IN CLOSER AGREEMENT THAT A DEEP
PACIFIC TROUGH WILL SLIDE THROUGH CALIFORNIA ON FRIDAY AND POSSIBLY
AS FAR SOUTH AS ARIZONA SOMETIME NEXT WEEKEND. WIDESPREAD SLIGHT
CHANCE POPS ARE IN THE FORECAST FOR FRIDAY. EITHER WAY IT IS FAIRLY
LIKELY THIS LOW WILL USER IN COOLER AND MUCH DRIER AIR...AND
POTENTIALLY END OUR MONSOON SEASON.

&&

.AVIATION...
SOUTH-CENTRAL AND SOUTHWEST ARIZONA INCLUDING KPHX...KIWA...KSDL...
ISOLATED TO WIDELY SCATTERED THUNDERSTORM ACTIVITY WILL PERSIST THIS
AFTERNOON AND EVENING OVER SOUTH-CENTRAL AZ...A FEW STORMS COULD
BRIEFLY IMPACT LOW DESERT TERMINALS WITH GUSTY OUTFLOWS UP TO 40
KT...AND REDUCED VISIBILITY DOWN TO 3SM IN BLDU. EXPECT SCT-BKN
CLOUD DECKS AOA 7000FT TO PERSIST OVERNIGHT TIMES INTO SUNDAY
MORNING. ONCE POTENTIAL FOR OUTFLOW BOUNDARIES DIMINISHES AFTER
04Z...WINDS WILL GENERALLY BE LIGHT...LESS THAN 10KT AND FAVOR THE
EAST SOUTHEAST AT ALL TERMINALS.

SOUTHEAST CALIFORNIA INCLUDING KIPL...AND KBLH...
OTHER THAN A FEW CLOUDS GENERALLY AOA 10KFT...EXPECT MOSTLY CLEAR
SKIES AND LIGHT WINDS OVERNIGHT THROUGH AT LEAST 18Z SUNDAY
AFTERNOON.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
MOISTURE RETREAT DUE TO WESTERLY FLOW WILL KEEP STORM CHANCES
MINIMAL THROUGH THURSDAY AND LIMITED TO THE HIGHER MOUNTAINS OF
SOUTH-CENTRAL ARIZONA. MEANWHILE...TEMPERATURES NUDGE UPWARD A FEW
DEGREES ABOVE NORMAL. HUMIDITIES ON THE LOWER DESERTS DROP BELOW 15
PERCENT THOUGH MAX HUMIDITIES REMAIN FAIR. NO STRONG WINDS ARE
EXPECTED DURING THIS TIME FRAME. ON FRIDAY...A PACIFIC WEATHER
SYSTEM WILL PULL MOISTURE NORTHWARD OVER THE REGION FOR A RETURN OF
STORM CHANCES INTO NEXT WEEKEND...MAINLY EAST OF THE LOWER COLORADO
RIVER VALLEY. IN ADDITION...COOLER TEMPERATURES AND BREEZY TO
LOCALLY WINDY CONDITIONS CAN BE EXPECTED AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

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






000
FXUS65 KPSR 202104
AFDPSR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PHOENIX AZ
205 PM MST SAT SEP 20 2014


.SYNOPSIS...
LINGERING MOISTURE ACROSS THE REGION AND LOW PRESSURE APPROACHING
FROM THE WEST WILL KEEP AT LEAST SLIGHT CHANCES FOR SHOWERS AND
THUNDERSTORMS FOR TODAY. DRIER AIR WILL GRADUALLY FILTER
INTO THE REGION SUNDAY AND MONDAY FOR A DECLINE IN STORM CHANCES.
SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE
HIGHER MOUNTAINS OF SOUTH-CENTRAL ARIZONA DURING THE MIDDLE OF NEXT
WEEK WITH SLIGHTLY ABOVE NORMAL TEMPERATURES. AN APPROACHING
PACIFIC WEATHER SYSTEM LATE NEXT WEEK WILL LEAD TO AN INCREASE IN
STORM CHANCES.

&&

.DISCUSSION...
MODEL THETA-E GRADIENT ALIGNED WELL WITH THE FAVORABLE LOCATIONS OF
HIGHER MOISTURE CONTENT AND GREATER INSTABILITY. THE RAP MLCAPE
VALUES JUST OVER 1500 J/KG ALONG AN AXIS FROM NOGALES TO BULLHEAD
CITY. WESTERN MARICOPA COUNTY...LA PAZ AND NORTHERN YUMA COUNTIES
LOOK TO BE THE FAVORABLE AREAS FOR CONVECTION THIS AFTERNOON AND
EVENING. CAN NOT RULE OUT ISOLATED STORMS SNEAKING IN TO NORTHERN
PINAL COUNTY FROM SOUTH-CENTRAL ARIZONA...AS THE GREATER TUCSON AREA
HAS BEEN INCREASING IN ACTIVITY LATE THIS MORNING. PRECIPITABLE
WATER VALUES HOVERING AROUND 1.5 INCHES ACROSS THE LOWER DESERTS AND
A VERY BROAD DIFLUENT MID-LAYER STRETCHING NORTH-NORTHWEST THROUGH
THE GREAT BASIN ALLOWS FOR CONVECTIVE DEVELOPMENT THIS AFTERNOON AND
EVENING. MOISTURE AND DYNAMICS ARE IN PLACE AND THE POTENTIAL ENERGY
IS THERE...NOW THE CHALLENGE WILL BE FOR A TRIGGER TO PUSH THE
DEVELOPMENT NEEDED FOR THUNDERSTORM DEVELOPMENT.

STORM CHANCES WILL BE ON THE DECLINE THROUGH MONDAY BEFORE COMING TO
A QUIET HOLDING PATTERN THROUGH THE WEEK. MONSOON MOISTURE LOOKS TO
HANG AROUND THIS WEEK BUT MAINLY ACROSS EASTERN ARIZONA. THE UPPER
LEVEL DISTURBANCE IS PROGGED TO MOVE NORTH THROUGH THE GREAT BASIN
BY MONDAY AND WILL ALLOW A WESTERLY FLOW TO SETTLE IN PLACE OVER THE
SOUTHWEST DESERTS AS WELL AS A DRYING TREND. WILL KEEP SLIGHT CHANCE
MENTION IN ZONE 24 FOR THE HIGHER TERRAIN LOCATIONS. TEMPERATURES
WILL HAVE LITTLE DAY TO DAY CHANGE...REMAINING AT OR A FEW DEGREES
ABOVE SEASONAL NORMAL WITH HIGH PRESSURE DOMINATING THE REGION
THROUGH MID WEEK.

THURSDAY THROUGH SATURDAY...ATTENTION THEN TURNS TO A POSSIBLE
SEASONAL TRANSITION SYSTEM FOR LATE WEEK INTO NEXT WEEKEND.
CONFIDENCE IS STILL NOT VERY HIGH ON THE SPECIFICS OF THE SYSTEM BUT
THE 00Z OPERATIONAL MODELS HAVE COME IN CLOSER AGREEMENT THAT A DEEP
PACIFIC TROUGH WILL SLIDE THROUGH CALIFORNIA ON FRIDAY AND POSSIBLY
AS FAR SOUTH AS ARIZONA SOMETIME NEXT WEEKEND. WIDESPREAD SLIGHT
CHANCE POPS ARE IN THE FORECAST FOR FRIDAY. EITHER WAY IT IS FAIRLY
LIKELY THIS LOW WILL USER IN COOLER AND MUCH DRIER AIR...AND
POTENTIALLY END OUR MONSOON SEASON.

&&

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

AN UPPER LOW CENTERED OFF THE COAST OF SOUTHERN CALIFORNIA WILL PULL
MONSOON MOISTURE NORTHWARD TODAY FOR SCT-BKN080-100 WITH SCATTERED
SHOWERS AND THUNDERSTORMS OVER THE HIGHER TERRAIN NORTH...EAST...AND
SOUTH...OF THE PHOENIX AREA AND ISOLATED ELSEWHERE. ONSET OF SHOWERS
POSSIBLE BEFORE 18Z. CONFIDENCE TOO LOW AN ANY GIVEN TAF SITE TO
INSERT TEMPO SHWRS/TSTMS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
MOISTURE RETREAT DUE TO WESTERLY FLOW WILL KEEP STORM CHANCES
MINIMAL THROUGH THURSDAY AND LIMITED TO THE HIGHER MOUNTAINS OF
SOUTH-CENTRAL ARIZONA. MEANWHILE...TEMPERATURES NUDGE UPWARD A FEW
DEGREES ABOVE NORMAL. HUMIDITIES ON THE LOWER DESERTS DROP BELOW 15
PERCENT THOUGH MAX HUMIDITIES REMAIN FAIR. NO STRONG WINDS ARE
EXPECTED DURING THIS TIME FRAME. ON FRIDAY...A PACIFIC WEATHER
SYSTEM WILL PULL MOISTURE NORTHWARD OVER THE REGION FOR A RETURN OF
STORM CHANCES...MAINLY EAST OF THE LOWER COLORADO RIVER VALLEY. IN
ADDITION...COOLER TEMPERATURES AND BREEZY TO LOCALLY WINDY
CONDITIONS CAN BE EXPECTED AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...DEWEY
AVIATION...AJ
FIRE WEATHER...AJ












000
FXUS65 KPSR 202104
AFDPSR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PHOENIX AZ
205 PM MST SAT SEP 20 2014


.SYNOPSIS...
LINGERING MOISTURE ACROSS THE REGION AND LOW PRESSURE APPROACHING
FROM THE WEST WILL KEEP AT LEAST SLIGHT CHANCES FOR SHOWERS AND
THUNDERSTORMS FOR TODAY. DRIER AIR WILL GRADUALLY FILTER
INTO THE REGION SUNDAY AND MONDAY FOR A DECLINE IN STORM CHANCES.
SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE
HIGHER MOUNTAINS OF SOUTH-CENTRAL ARIZONA DURING THE MIDDLE OF NEXT
WEEK WITH SLIGHTLY ABOVE NORMAL TEMPERATURES. AN APPROACHING
PACIFIC WEATHER SYSTEM LATE NEXT WEEK WILL LEAD TO AN INCREASE IN
STORM CHANCES.

&&

.DISCUSSION...
MODEL THETA-E GRADIENT ALIGNED WELL WITH THE FAVORABLE LOCATIONS OF
HIGHER MOISTURE CONTENT AND GREATER INSTABILITY. THE RAP MLCAPE
VALUES JUST OVER 1500 J/KG ALONG AN AXIS FROM NOGALES TO BULLHEAD
CITY. WESTERN MARICOPA COUNTY...LA PAZ AND NORTHERN YUMA COUNTIES
LOOK TO BE THE FAVORABLE AREAS FOR CONVECTION THIS AFTERNOON AND
EVENING. CAN NOT RULE OUT ISOLATED STORMS SNEAKING IN TO NORTHERN
PINAL COUNTY FROM SOUTH-CENTRAL ARIZONA...AS THE GREATER TUCSON AREA
HAS BEEN INCREASING IN ACTIVITY LATE THIS MORNING. PRECIPITABLE
WATER VALUES HOVERING AROUND 1.5 INCHES ACROSS THE LOWER DESERTS AND
A VERY BROAD DIFLUENT MID-LAYER STRETCHING NORTH-NORTHWEST THROUGH
THE GREAT BASIN ALLOWS FOR CONVECTIVE DEVELOPMENT THIS AFTERNOON AND
EVENING. MOISTURE AND DYNAMICS ARE IN PLACE AND THE POTENTIAL ENERGY
IS THERE...NOW THE CHALLENGE WILL BE FOR A TRIGGER TO PUSH THE
DEVELOPMENT NEEDED FOR THUNDERSTORM DEVELOPMENT.

STORM CHANCES WILL BE ON THE DECLINE THROUGH MONDAY BEFORE COMING TO
A QUIET HOLDING PATTERN THROUGH THE WEEK. MONSOON MOISTURE LOOKS TO
HANG AROUND THIS WEEK BUT MAINLY ACROSS EASTERN ARIZONA. THE UPPER
LEVEL DISTURBANCE IS PROGGED TO MOVE NORTH THROUGH THE GREAT BASIN
BY MONDAY AND WILL ALLOW A WESTERLY FLOW TO SETTLE IN PLACE OVER THE
SOUTHWEST DESERTS AS WELL AS A DRYING TREND. WILL KEEP SLIGHT CHANCE
MENTION IN ZONE 24 FOR THE HIGHER TERRAIN LOCATIONS. TEMPERATURES
WILL HAVE LITTLE DAY TO DAY CHANGE...REMAINING AT OR A FEW DEGREES
ABOVE SEASONAL NORMAL WITH HIGH PRESSURE DOMINATING THE REGION
THROUGH MID WEEK.

THURSDAY THROUGH SATURDAY...ATTENTION THEN TURNS TO A POSSIBLE
SEASONAL TRANSITION SYSTEM FOR LATE WEEK INTO NEXT WEEKEND.
CONFIDENCE IS STILL NOT VERY HIGH ON THE SPECIFICS OF THE SYSTEM BUT
THE 00Z OPERATIONAL MODELS HAVE COME IN CLOSER AGREEMENT THAT A DEEP
PACIFIC TROUGH WILL SLIDE THROUGH CALIFORNIA ON FRIDAY AND POSSIBLY
AS FAR SOUTH AS ARIZONA SOMETIME NEXT WEEKEND. WIDESPREAD SLIGHT
CHANCE POPS ARE IN THE FORECAST FOR FRIDAY. EITHER WAY IT IS FAIRLY
LIKELY THIS LOW WILL USER IN COOLER AND MUCH DRIER AIR...AND
POTENTIALLY END OUR MONSOON SEASON.

&&

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

AN UPPER LOW CENTERED OFF THE COAST OF SOUTHERN CALIFORNIA WILL PULL
MONSOON MOISTURE NORTHWARD TODAY FOR SCT-BKN080-100 WITH SCATTERED
SHOWERS AND THUNDERSTORMS OVER THE HIGHER TERRAIN NORTH...EAST...AND
SOUTH...OF THE PHOENIX AREA AND ISOLATED ELSEWHERE. ONSET OF SHOWERS
POSSIBLE BEFORE 18Z. CONFIDENCE TOO LOW AN ANY GIVEN TAF SITE TO
INSERT TEMPO SHWRS/TSTMS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
MOISTURE RETREAT DUE TO WESTERLY FLOW WILL KEEP STORM CHANCES
MINIMAL THROUGH THURSDAY AND LIMITED TO THE HIGHER MOUNTAINS OF
SOUTH-CENTRAL ARIZONA. MEANWHILE...TEMPERATURES NUDGE UPWARD A FEW
DEGREES ABOVE NORMAL. HUMIDITIES ON THE LOWER DESERTS DROP BELOW 15
PERCENT THOUGH MAX HUMIDITIES REMAIN FAIR. NO STRONG WINDS ARE
EXPECTED DURING THIS TIME FRAME. ON FRIDAY...A PACIFIC WEATHER
SYSTEM WILL PULL MOISTURE NORTHWARD OVER THE REGION FOR A RETURN OF
STORM CHANCES...MAINLY EAST OF THE LOWER COLORADO RIVER VALLEY. IN
ADDITION...COOLER TEMPERATURES AND BREEZY TO LOCALLY WINDY
CONDITIONS CAN BE EXPECTED AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...DEWEY
AVIATION...AJ
FIRE WEATHER...AJ











000
FXUS65 KPSR 201534
AFDPSR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PHOENIX AZ
835 AM MST SAT SEP 20 2014


.SYNOPSIS...
LINGERING MOISTURE ACROSS THE REGION AND LOW PRESSURE APPROACHING
FROM THE WEST WILL KEEP AT LEAST SLIGHT CHANCES FOR SHOWERS AND
THUNDERSTORMS FOR TODAY. DRIER AIR WILL GRADUALLY FILTER
INTO THE REGION SUNDAY AND MONDAY FOR A DECLINE IN STORM CHANCES.
SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE
HIGHER MOUNTAINS OF SOUTH-CENTRAL ARIZONA DURING THE MIDDLE OF NEXT
WEEK WITH SLIGHTLY ABOVE NORMAL TEMPERATURES. AN APPROACHING
PACIFIC WEATHER SYSTEM LATE NEXT WEEK WILL LEAD TO AN INCREASE IN
STORM CHANCES.

&&

.DISCUSSION...
ANOTHER HUMID MORNING AS YOU WALK OUTSIDE. CURRENT DEWPOINT READINGS
ACROSS PHOENIX METRO RANGE FROM THE MID 60S TO MID 70S AND ACROSS
SOUTHEAST CALIFORNIA 60S TO 70S AS WELL WITH SOME DRIER AIR FARTHER
NORTH INTO JOSHUA TREE NATIONAL PARK AND SAN BERNARDINO COUNTY. THE
STRONG UPPER LEVEL LOW CONTINUES TO SPIN OFF SHORE OF SOUTHERN
CALIFORNIA WHILE HIGH PRESSURE REMAINS ACROSS SOUTHERN NEW MEXICO
AND WEST TEXAS...GIVING WAY TO A SOUTHERLY FETCH OF MOISTURE
STREAMING INTO ARIZONA. THIS SHOULD REMAIN IN PLACE THE REMAINDER OF
TODAY...CREATING DIFLUENT CONDITIONS FROM THE LOWER COLORADO RIVER
VALLEY UP THROUGH EASTERN NEVADA AND WESTERN UTAH WHERE CONDITIONS
SHOULD BE MORE FAVORABLE FOR THUNDERSTORM ACTIVITY. THE FORECAST IS
IN GOOD SHAPE FROM THE PREVIOUS SHIFT SO NO UPDATES NEEDED AT THIS
TIME AND THE PREVIOUS DISCUSSION STILL APPLIES.

.PREVIOUS DISCUSSION.../ISSUED 248 AM MST/PDT 20 SEPT 2014/...
MONSOON MOISTURE WILL STILL BE A FACTOR OVER THE NEXT WEEK...BUT
MAINLY ACROSS EASTERN PORTIONS OF ARIZONA. IN THE NEAR TERM...A
CUT-OFF UPPER LOW CENTERED OFF THE SOUTHERN CALIFORNIA COAST IS
ALLOWING FOR AN INCREASE IN SOUTHERLY FLOW ACROSS THE AREA...THUS
TAPPING INTO ADDITIONAL MOISTURE OVER NORTHERN MEXICO. CURRENT IR
IMAGERY HINTS AT SOME OF THIS MOISTURE ADVECTION IN THE FORM OF
ACCAS CLOUDS ACROSS SOUTHERN ARIZONA. HI-RES MODELS DO INDICATE SOME
LIGHT SHOWERS WILL BE PRESENT ACROSS YUMA COUNTY AFTER 12Z THIS
MORNING IN THE MAIN MOISTURE ADVECTION AREA. HAVE INTRODUCED SOME
SLIGHT CHANCE POPS ACROSS YUMA AND SOUTHERN MARICOPA COUNTIES
STARTING AROUND 12Z AND THEN EXPANDING AS THE DAY PROGRESSES.

THE UPPER LOW WILL REMAIN NEARLY STATIONARY UNTIL THIS EVENING WHEN
GOOD MODEL AGREEMENT SHOWS IT FINALLY LIFTING NORTHEASTWARD INTO THE
GREAT BASIN. A FAIRLY STRONG UPPER JET MAX ACROSS SOUTHEAST
CALIFORNIA WILL ALLOW FOR A FAVORABLE AREA OF ASCENT TODAY MAINLY
FOCUSED ACROSS WESTERN ARIZONA. COULD SEE SOME ISOLATED SHOWERS AND
THUNDERSTORMS ACROSS ALL BUT THE IMPERIAL VALLEY THIS AFTERNOON WITH
THE BEST CHANCES ACROSS LA PAZ COUNTY CLOSER TO THE FAVORED ASCENT
AREA AND ACROSS THE HIGHER TERRAIN OF GILA COUNTY. ACTIVITY SHOULD
REMAIN FAIRLY ISOLATED AS INSTABILITY WILL BE SOMEWHAT LIMITED BASED
ON FORECAST SOUNDINGS. THERE WILL BE SOME POTENTIAL FOR STRONG GUSTY
WINDS TODAY...MAINLY ACROSS SOUTHWEST ARIZONA WHERE MID LEVEL WINDS
WILL BE 15-25 KNOTS. DON/T FEEL THERE WILL BE MUCH OF A FLOOD THREAT
TODAY WITH A SOUTHERLY STEERING FLOW AT 10-20 KNOTS AND PRECIPITABLE
WATER VALUES OF 1.25-1.50 INCHES.

AS THE UPPER LOW LIFTS INTO THE GREAT BASIN ON
SUNDAY...SOUTHWESTERLY MID AND UPPER LEVEL FLOW WILL BRING IN DRIER
AIR FROM THE SOUTHWEST. THE LOW LEVELS WILL REMAIN FAIRLY MOIST FROM
MARICOPA COUNTY EASTWARD ALLOWING FOR A CONTINUED SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS FOR SUNDAY MAINLY OVER THE HIGHER TERRAIN
NORTH AND EAST OF PHOENIX. FURTHER DRYING WILL TAKE PLACE EARLY NEXT
WEEK...CONFINING ANY SLIGHT CHANCE POPS ONLY ACROSS HIGHER TERRAIN
AREAS EAST OF PHOENIX ON MONDAY AND TUESDAY. UPPER LEVEL RIDGING
TAKES OVER STARTING MONDAY WITH 500MB HEIGHTS BUILDING TO AROUND
590DM. GIVEN THE HIGH HEIGHTS AND FORECAST 850MB TEMPERATURES OF
23-25C...FEEL CONFIDENT THAT LOWER DESERT LOCATIONS WILL TOP OUT
ABOVE 100 STARTING MONDAY. DURING THE MIDDLE OF NEXT WEEK...THE
UPPER RIDGE WILL AMPLIFY AHEAD OF A DEEPENING UPPER TROUGH OFF THE
PACIFIC NORTHWEST. THIS WILL KEEP TEMPERATURES ON THE WARM
SIDE...AROUND 3-5 DEGREES ABOVE NORMAL...AT LEAST THROUGH THURSDAY
AND LIMIT ANY SHOWER AND THUNDERSTORM ACTIVITY TO FAR EASTERN GILA
COUNTY.

ATTENTION THEN TURNS TO A POSSIBLE SEASONAL TRANSITION SYSTEM FOR
LATE NEXT WEEK INTO NEXT WEEKEND. CONFIDENCE IS STILL NOT VERY HIGH
ON THE SPECIFICS OF THE SYSTEM...BUT THE 00Z MODEL RUNS CAME INTO
FAIRLY GOOD AGREEMENT THAT A DEEP PACIFIC TROUGH WILL SLIDE THROUGH
CALIFORNIA ON FRIDAY AND POSSIBLY AS FAR SOUTH AS ARIZONA SOMETIME
NEXT WEEKEND. WIDESPREAD SLIGHT CHANCE POPS ARE IN THE FORECAST FOR
FRIDAY...AND MAY NEED TO RAMP UP POPS OVER THE NEXT FEW DAYS IF THE
TROUGH LOOKS LIKE IT WILL DIG FAR ENOUGH SOUTH INTO OUR AREA. EITHER
WAY IT IS FAIRLY LIKELY THIS LOW WILL USHER IN COOLER AND MUCH DRIER
AIR...AND POTENTIALLY ENDING OUR MONSOON SEASON.

&&

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

AN UPPER LOW CENTERED OFF THE COAST OF SOUTHERN CALIFORNIA WILL PULL
MONSOON MOISTURE NORTHWARD TODAY FOR SCT-BKN080-100 WITH SCATTERED
SHOWERS AND THUNDERSTORMS OVER THE HIGHER TERRAIN NORTH...EAST...AND
SOUTH...OF THE PHOENIX AREA AND ISOLATED ELSEWHERE. ONSET OF SHOWERS
POSSIBLE BEFORE 18Z. CONFIDENCE TOO LOW AN ANY GIVEN TAF SITE TO
INSERT TEMPO SHWRS/TSTMS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
MOISTURE RETREAT DUE TO WESTERLY FLOW WILL KEEP STORM CHANCES
MINIMAL THROUGH THURSDAY AND LIMITED TO THE HIGHER MOUNTAINS OF
SOUTH-CENTRAL ARIZONA. MEANWHILE...TEMPERATURES NUDGE UPWARD A FEW
DEGREES ABOVE NORMAL. HUMIDITIES ON THE LOWER DESERTS DROP BELOW 15
PERCENT THOUGH MAX HUMIDITIES REMAIN FAIR. NO STRONG WINDS ARE
EXPECTED DURING THIS TIME FRAME. ON FRIDAY...A PACIFIC WEATHER
SYSTEM WILL PULL MOISTURE NORTHWARD OVER THE REGION FOR A RETURN OF
STORM CHANCES...MAINLY EAST OF THE LOWER COLORADO RIVER VALLEY. IN
ADDITION...COOLER TEMPERATURES AND BREEZY TO LOCALLY WINDY
CONDITIONS CAN BE EXPECTED AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...DEWEY
PREVIOUS DISCUSSION...KUHLMAN
AVIATION...AJ
FIRE WEATHER...AJ








000
FXUS65 KPSR 201233 AAA
AFDPSR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PHOENIX AZ
535 AM MST SAT SEP 20 2014

.UPDATE...
UPDATED AVIATION AND FIRE WEATHER SECTIONS.

&&

.SYNOPSIS...
LINGERING MOISTURE ACROSS THE REGION AND LOW PRESSURE APPROACHING
FROM THE WEST WILL KEEP AT LEAST SLIGHT CHANCES FOR SHOWERS AND
THUNDERSTORMS FOR TODAY. DRIER AIR WILL GRADUALLY FILTER
INTO THE REGION SUNDAY AND MONDAY FOR A DECLINE IN STORM CHANCES.
SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE
HIGHER MOUNTAINS OF SOUTH-CENTRAL ARIZONA DURING THE MIDDLE OF NEXT
WEEK WITH SLIGHTLY ABOVE NORMAL TEMPERATURES. AN APPROACHING
PACIFIC WEATHER SYSTEM LATE NEXT WEEK WILL LEAD TO AN INCREASE IN
STORM CHANCES.

&&

.DISCUSSION...
MONSOON MOISTURE WILL STILL BE A FACTOR OVER THE NEXT WEEK...BUT
MAINLY ACROSS EASTERN PORTIONS OF ARIZONA. IN THE NEAR TERM...A
CUT-OFF UPPER LOW CENTERED OFF THE SOUTHERN CALIFORNIA COAST IS
ALLOWING FOR AN INCREASE IN SOUTHERLY FLOW ACROSS THE AREA...THUS
TAPPING INTO ADDITIONAL MOISTURE OVER NORTHERN MEXICO. CURRENT IR
IMAGERY HINTS AT SOME OF THIS MOISTURE ADVECTION IN THE FORM OF
ACCAS CLOUDS ACROSS SOUTHERN ARIZONA. HI-RES MODELS DO INDICATE SOME
LIGHT SHOWERS WILL BE PRESENT ACROSS YUMA COUNTY AFTER 12Z THIS
MORNING IN THE MAIN MOISTURE ADVECTION AREA. HAVE INTRODUCED SOME
SLIGHT CHANCE POPS ACROSS YUMA AND SOUTHERN MARICOPA COUNTIES
STARTING AROUND 12Z AND THEN EXPANDING AS THE DAY PROGRESSES.

THE UPPER LOW WILL REMAIN NEARLY STATIONARY UNTIL THIS EVENING WHEN
GOOD MODEL AGREEMENT SHOWS IT FINALLY LIFTING NORTHEASTWARD INTO THE
GREAT BASIN. A FAIRLY STRONG UPPER JET MAX ACROSS SOUTHEAST
CALIFORNIA WILL ALLOW FOR A FAVORABLE AREA OF ASCENT TODAY MAINLY
FOCUSED ACROSS WESTERN ARIZONA. COULD SEE SOME ISOLATED SHOWERS AND
THUNDERSTORMS ACROSS ALL BUT THE IMPERIAL VALLEY THIS AFTERNOON WITH
THE BEST CHANCES ACROSS LA PAZ COUNTY CLOSER TO THE FAVORED ASCENT
AREA AND ACROSS THE HIGHER TERRAIN OF GILA COUNTY. ACTIVITY SHOULD
REMAIN FAIRLY ISOLATED AS INSTABILITY WILL BE SOMEWHAT LIMITED BASED
ON FORECAST SOUNDINGS. THERE WILL BE SOME POTENTIAL FOR STRONG GUSTY
WINDS TODAY...MAINLY ACROSS SOUTHWEST ARIZONA WHERE MID LEVEL WINDS
WILL BE 15-25 KNOTS. DON/T FEEL THERE WILL BE MUCH OF A FLOOD THREAT
TODAY WITH A SOUTHERLY STEERING FLOW AT 10-20 KNOTS AND PRECIPITABLE
WATER VALUES OF 1.25-1.50 INCHES.

AS THE UPPER LOW LIFTS INTO THE GREAT BASIN ON
SUNDAY...SOUTHWESTERLY MID AND UPPER LEVEL FLOW WILL BRING IN DRIER
AIR FROM THE SOUTHWEST. THE LOW LEVELS WILL REMAIN FAIRLY MOIST FROM
MARICOPA COUNTY EASTWARD ALLOWING FOR A CONTINUED SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS FOR SUNDAY MAINLY OVER THE HIGHER TERRAIN
NORTH AND EAST OF PHOENIX. FURTHER DRYING WILL TAKE PLACE EARLY NEXT
WEEK...CONFINING ANY SLIGHT CHANCE POPS ONLY ACROSS HIGHER TERRAIN
AREAS EAST OF PHOENIX ON MONDAY AND TUESDAY. UPPER LEVEL RIDGING
TAKES OVER STARTING MONDAY WITH 500MB HEIGHTS BUILDING TO AROUND
590DM. GIVEN THE HIGH HEIGHTS AND FORECAST 850MB TEMPERATURES OF
23-25C...FEEL CONFIDENT THAT LOWER DESERT LOCATIONS WILL TOP OUT
ABOVE 100 STARTING MONDAY. DURING THE MIDDLE OF NEXT WEEK...THE
UPPER RIDGE WILL AMPLIFY AHEAD OF A DEEPENING UPPER TROUGH OFF THE
PACIFIC NORTHWEST. THIS WILL KEEP TEMPERATURES ON THE WARM
SIDE...AROUND 3-5 DEGREES ABOVE NORMAL...AT LEAST THROUGH THURSDAY
AND LIMIT ANY SHOWER AND THUNDERSTORM ACTIVITY TO FAR EASTERN GILA
COUNTY.

ATTENTION THEN TURNS TO A POSSIBLE SEASONAL TRANSITION SYSTEM FOR
LATE NEXT WEEK INTO NEXT WEEKEND. CONFIDENCE IS STILL NOT VERY HIGH
ON THE SPECIFICS OF THE SYSTEM...BUT THE 00Z MODEL RUNS CAME INTO
FAIRLY GOOD AGREEMENT THAT A DEEP PACIFIC TROUGH WILL SLIDE THROUGH
CALIFORNIA ON FRIDAY AND POSSIBLY AS FAR SOUTH AS ARIZONA SOMETIME
NEXT WEEKEND. WIDESPREAD SLIGHT CHANCE POPS ARE IN THE FORECAST FOR
FRIDAY...AND MAY NEED TO RAMP UP POPS OVER THE NEXT FEW DAYS IF THE
TROUGH LOOKS LIKE IT WILL DIG FAR ENOUGH SOUTH INTO OUR AREA. EITHER
WAY IT IS FAIRLY LIKELY THIS LOW WILL USHER IN COOLER AND MUCH DRIER
AIR...AND POTENTIALLY ENDING OUR MONSOON SEASON.

&&

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

AN UPPER LOW CENTERED OFF THE COAST OF SOUTHERN CALIFORNIA WILL PULL
MONSOON MOISTURE NORTHWARD TODAY FOR SCT-BKN080-100 WITH SCATTERED
SHOWERS AND THUNDERSTORMS OVER THE HIGHER TERRAIN NORTH...EAST...AND
SOUTH...OF THE PHOENIX AREA AND ISOLATED ELSEWHERE. ONSET OF SHOWERS
POSSIBLE BEFORE 18Z. CONFIDENCE TOO LOW AN ANY GIVEN TAF SITE TO
INSERT TEMPO SHWRS/TSTMS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
MOISTURE RETREAT DUE TO WESTERLY FLOW WILL KEEP STORM CHANCES
MINIMAL THROUGH THURSDAY AND LIMITED TO THE HIGHER MOUNTAINS OF
SOUTH-CENTRAL ARIZONA. MEANWHILE...TEMPERATURES NUDGE UPWARD A FEW
DEGREES ABOVE NORMAL. HUMIDITIES ON THE LOWER DESERTS DROP BELOW 15
PERCENT THOUGH MAX HUMIDITIES REMAIN FAIR. NO STRONG WINDS ARE
EXPECTED DURING THIS TIME FRAME. ON FRIDAY...A PACIFIC WEATHER
SYSTEM WILL PULL MOISTURE NORTHWARD OVER THE REGION FOR A RETURN OF
STORM CHANCES...MAINLY EAST OF THE LOWER COLORADO RIVER VALLEY. IN
ADDITION...COOLER TEMPERATURES AND BREEZY TO LOCALLY WINDY
CONDITIONS CAN BE EXPECTED AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...KUHLMAN
AVIATION...AJ
FIRE WEATHER...AJ








000
FXUS65 KPSR 200948
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
248 AM MST SAT SEP 20 2014

.SYNOPSIS...
LINGERING MOISTURE ACROSS THE REGION AND LOW PRESSURE APPROACHING
FROM THE WEST WILL KEEP AT LEAST SLIGHT CHANCES FOR SHOWERS AND
THUNDERSTORMS FOR TODAY. DRIER AIR WILL GRADUALLY FILTER
INTO THE REGION SUNDAY AND MONDAY FOR A DECLINE IN STORM CHANCES.
SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE
HIGHER MOUNTAINS OF SOUTH-CENTRAL ARIZONA DURING THE MIDDLE OF NEXT
WEEK WITH SLIGHTLY ABOVE NORMAL TEMPERATURES. AN APPROACHING
PACIFIC WEATHER SYSTEM LATE NEXT WEEK WILL LEAD TO AN INCREASE IN
STORM CHANCES.

&&

.DISCUSSION...
MONSOON MOISTURE WILL STILL BE A FACTOR OVER THE NEXT WEEK...BUT
MAINLY ACROSS EASTERN PORTIONS OF ARIZONA. IN THE NEAR TERM...A
CUT-OFF UPPER LOW CENTERED OFF THE SOUTHERN CALIFORNIA COAST IS
ALLOWING FOR AN INCREASE IN SOUTHERLY FLOW ACROSS THE AREA...THUS
TAPPING INTO ADDITIONAL MOISTURE OVER NORTHERN MEXICO. CURRENT IR
IMAGERY HINTS AT SOME OF THIS MOISTURE ADVECTION IN THE FORM OF
ACCAS CLOUDS ACROSS SOUTHERN ARIZONA. HI-RES MODELS DO INDICATE SOME
LIGHT SHOWERS WILL BE PRESENT ACROSS YUMA COUNTY AFTER 12Z THIS
MORNING IN THE MAIN MOISTURE ADVECTION AREA. HAVE INTRODUCED SOME
SLIGHT CHANCE POPS ACROSS YUMA AND SOUTHERN MARICOPA COUNTIES
STARTING AROUND 12Z AND THEN EXPANDING AS THE DAY PROGRESSES.

THE UPPER LOW WILL REMAIN NEARLY STATIONARY UNTIL THIS EVENING WHEN
GOOD MODEL AGREEMENT SHOWS IT FINALLY LIFTING NORTHEASTWARD INTO THE
GREAT BASIN. A FAIRLY STRONG UPPER JET MAX ACROSS SOUTHEAST
CALIFORNIA WILL ALLOW FOR A FAVORABLE AREA OF ASCENT TODAY MAINLY
FOCUSED ACROSS WESTERN ARIZONA. COULD SEE SOME ISOLATED SHOWERS AND
THUNDERSTORMS ACROSS ALL BUT THE IMPERIAL VALLEY THIS AFTERNOON WITH
THE BEST CHANCES ACROSS LA PAZ COUNTY CLOSER TO THE FAVORED ASCENT
AREA AND ACROSS THE HIGHER TERRAIN OF GILA COUNTY. ACTIVITY SHOULD
REMAIN FAIRLY ISOLATED AS INSTABILITY WILL BE SOMEWHAT LIMITED BASED
ON FORECAST SOUNDINGS. THERE WILL BE SOME POTENTIAL FOR STRONG GUSTY
WINDS TODAY...MAINLY ACROSS SOUTHWEST ARIZONA WHERE MID LEVEL WINDS
WILL BE 15-25 KNOTS. DON/T FEEL THERE WILL BE MUCH OF A FLOOD THREAT
TODAY WITH A SOUTHERLY STEERING FLOW AT 10-20 KNOTS AND PRECIPITABLE
WATER VALUES OF 1.25-1.50 INCHES.

AS THE UPPER LOW LIFTS INTO THE GREAT BASIN ON
SUNDAY...SOUTHWESTERLY MID AND UPPER LEVEL FLOW WILL BRING IN DRIER
AIR FROM THE SOUTHWEST. THE LOW LEVELS WILL REMAIN FAIRLY MOIST FROM
MARICOPA COUNTY EASTWARD ALLOWING FOR A CONTINUED SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS FOR SUNDAY MAINLY OVER THE HIGHER TERRAIN
NORTH AND EAST OF PHOENIX. FURTHER DRYING WILL TAKE PLACE EARLY NEXT
WEEK...CONFINING ANY SLIGHT CHANCE POPS ONLY ACROSS HIGHER TERRAIN
AREAS EAST OF PHOENIX ON MONDAY AND TUESDAY. UPPER LEVEL RIDGING
TAKES OVER STARTING MONDAY WITH 500MB HEIGHTS BUILDING TO AROUND
590DM. GIVEN THE HIGH HEIGHTS AND FORECAST 850MB TEMPERATURES OF
23-25C...FEEL CONFIDENT THAT LOWER DESERT LOCATIONS WILL TOP OUT
ABOVE 100 STARTING MONDAY. DURING THE MIDDLE OF NEXT WEEK...THE
UPPER RIDGE WILL AMPLIFY AHEAD OF A DEEPENING UPPER TROUGH OFF THE
PACIFIC NORTHWEST. THIS WILL KEEP TEMPERATURES ON THE WARM
SIDE...AROUND 3-5 DEGREES ABOVE NORMAL...AT LEAST THROUGH THURSDAY
AND LIMIT ANY SHOWER AND THUNDERSTORM ACTIVITY TO FAR EASTERN GILA
COUNTY.

ATTENTION THEN TURNS TO A POSSIBLE SEASONAL TRANSITION SYSTEM FOR
LATE NEXT WEEK INTO NEXT WEEKEND. CONFIDENCE IS STILL NOT VERY HIGH
ON THE SPECIFICS OF THE SYSTEM...BUT THE 00Z MODEL RUNS CAME INTO
FAIRLY GOOD AGREEMENT THAT A DEEP PACIFIC TROUGH WILL SLIDE THROUGH
CALIFORNIA ON FRIDAY AND POSSIBLY AS FAR SOUTH AS ARIZONA SOMETIME
NEXT WEEKEND. WIDESPREAD SLIGHT CHANCE POPS ARE IN THE FORECAST FOR
FRIDAY...AND MAY NEED TO RAMP UP POPS OVER THE NEXT FEW DAYS IF THE
TROUGH LOOKS LIKE IT WILL DIG FAR ENOUGH SOUTH INTO OUR AREA. EITHER
WAY IT IS FAIRLY LIKELY THIS LOW WILL USHER IN COOLER AND MUCH DRIER
AIR...AND POTENTIALLY ENDING OUR MONSOON SEASON.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...

THROUGH 19Z SAT...SCT-BKN CLDS AOA 10 THSD MSL. LIGHT WIND UNDER 8
KNOTS.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...

MAINLY CLEAR SKIES AND LIGHT WIND TO PREVAIL ACROSS THE AREA THROUGH
19Z SAT.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
RATHER DRY WESTERLY FLOW TO KEEP SKIES MAINLY CLEAR THROUGH THE
FORECAST PERIOD AT MOST LOCATIONS ACROSS THE REGION...WITH THE
EXCEPTION OF THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA...WHERE
LINGERING MOISTURE MAY ALLOW ISOLATED SHOWERS/THUNDERSTORMS TO
DEVELOP EACH AFTERNOON/EARLY EVENING. MINIMUM RELATIVE HUMIDITIES TO
FALL INTO THE 20 TO 30 PERCENT RANGE EACH AFTERNOON...WITH GOOD TO
EXCELLENT OVERNIGHT RECOVERIES. WINDS TO REMAIN MAINLY ON THE LIGHT
SIDE...MAINLY IN THE 5 TO 15 MPH RANGE...WITH THE USUAL DIURNAL
TRENDS TO PREVAIL AT MOST LOCATIONS.


&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...KUHLMAN
AVIATION...VASQUEZ
FIRE WEATHER...MEYERS/PERCHA












000
FXUS65 KPSR 200948
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
248 AM MST SAT SEP 20 2014

.SYNOPSIS...
LINGERING MOISTURE ACROSS THE REGION AND LOW PRESSURE APPROACHING
FROM THE WEST WILL KEEP AT LEAST SLIGHT CHANCES FOR SHOWERS AND
THUNDERSTORMS FOR TODAY. DRIER AIR WILL GRADUALLY FILTER
INTO THE REGION SUNDAY AND MONDAY FOR A DECLINE IN STORM CHANCES.
SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CONFINED TO THE
HIGHER MOUNTAINS OF SOUTH-CENTRAL ARIZONA DURING THE MIDDLE OF NEXT
WEEK WITH SLIGHTLY ABOVE NORMAL TEMPERATURES. AN APPROACHING
PACIFIC WEATHER SYSTEM LATE NEXT WEEK WILL LEAD TO AN INCREASE IN
STORM CHANCES.

&&

.DISCUSSION...
MONSOON MOISTURE WILL STILL BE A FACTOR OVER THE NEXT WEEK...BUT
MAINLY ACROSS EASTERN PORTIONS OF ARIZONA. IN THE NEAR TERM...A
CUT-OFF UPPER LOW CENTERED OFF THE SOUTHERN CALIFORNIA COAST IS
ALLOWING FOR AN INCREASE IN SOUTHERLY FLOW ACROSS THE AREA...THUS
TAPPING INTO ADDITIONAL MOISTURE OVER NORTHERN MEXICO. CURRENT IR
IMAGERY HINTS AT SOME OF THIS MOISTURE ADVECTION IN THE FORM OF
ACCAS CLOUDS ACROSS SOUTHERN ARIZONA. HI-RES MODELS DO INDICATE SOME
LIGHT SHOWERS WILL BE PRESENT ACROSS YUMA COUNTY AFTER 12Z THIS
MORNING IN THE MAIN MOISTURE ADVECTION AREA. HAVE INTRODUCED SOME
SLIGHT CHANCE POPS ACROSS YUMA AND SOUTHERN MARICOPA COUNTIES
STARTING AROUND 12Z AND THEN EXPANDING AS THE DAY PROGRESSES.

THE UPPER LOW WILL REMAIN NEARLY STATIONARY UNTIL THIS EVENING WHEN
GOOD MODEL AGREEMENT SHOWS IT FINALLY LIFTING NORTHEASTWARD INTO THE
GREAT BASIN. A FAIRLY STRONG UPPER JET MAX ACROSS SOUTHEAST
CALIFORNIA WILL ALLOW FOR A FAVORABLE AREA OF ASCENT TODAY MAINLY
FOCUSED ACROSS WESTERN ARIZONA. COULD SEE SOME ISOLATED SHOWERS AND
THUNDERSTORMS ACROSS ALL BUT THE IMPERIAL VALLEY THIS AFTERNOON WITH
THE BEST CHANCES ACROSS LA PAZ COUNTY CLOSER TO THE FAVORED ASCENT
AREA AND ACROSS THE HIGHER TERRAIN OF GILA COUNTY. ACTIVITY SHOULD
REMAIN FAIRLY ISOLATED AS INSTABILITY WILL BE SOMEWHAT LIMITED BASED
ON FORECAST SOUNDINGS. THERE WILL BE SOME POTENTIAL FOR STRONG GUSTY
WINDS TODAY...MAINLY ACROSS SOUTHWEST ARIZONA WHERE MID LEVEL WINDS
WILL BE 15-25 KNOTS. DON/T FEEL THERE WILL BE MUCH OF A FLOOD THREAT
TODAY WITH A SOUTHERLY STEERING FLOW AT 10-20 KNOTS AND PRECIPITABLE
WATER VALUES OF 1.25-1.50 INCHES.

AS THE UPPER LOW LIFTS INTO THE GREAT BASIN ON
SUNDAY...SOUTHWESTERLY MID AND UPPER LEVEL FLOW WILL BRING IN DRIER
AIR FROM THE SOUTHWEST. THE LOW LEVELS WILL REMAIN FAIRLY MOIST FROM
MARICOPA COUNTY EASTWARD ALLOWING FOR A CONTINUED SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS FOR SUNDAY MAINLY OVER THE HIGHER TERRAIN
NORTH AND EAST OF PHOENIX. FURTHER DRYING WILL TAKE PLACE EARLY NEXT
WEEK...CONFINING ANY SLIGHT CHANCE POPS ONLY ACROSS HIGHER TERRAIN
AREAS EAST OF PHOENIX ON MONDAY AND TUESDAY. UPPER LEVEL RIDGING
TAKES OVER STARTING MONDAY WITH 500MB HEIGHTS BUILDING TO AROUND
590DM. GIVEN THE HIGH HEIGHTS AND FORECAST 850MB TEMPERATURES OF
23-25C...FEEL CONFIDENT THAT LOWER DESERT LOCATIONS WILL TOP OUT
ABOVE 100 STARTING MONDAY. DURING THE MIDDLE OF NEXT WEEK...THE
UPPER RIDGE WILL AMPLIFY AHEAD OF A DEEPENING UPPER TROUGH OFF THE
PACIFIC NORTHWEST. THIS WILL KEEP TEMPERATURES ON THE WARM
SIDE...AROUND 3-5 DEGREES ABOVE NORMAL...AT LEAST THROUGH THURSDAY
AND LIMIT ANY SHOWER AND THUNDERSTORM ACTIVITY TO FAR EASTERN GILA
COUNTY.

ATTENTION THEN TURNS TO A POSSIBLE SEASONAL TRANSITION SYSTEM FOR
LATE NEXT WEEK INTO NEXT WEEKEND. CONFIDENCE IS STILL NOT VERY HIGH
ON THE SPECIFICS OF THE SYSTEM...BUT THE 00Z MODEL RUNS CAME INTO
FAIRLY GOOD AGREEMENT THAT A DEEP PACIFIC TROUGH WILL SLIDE THROUGH
CALIFORNIA ON FRIDAY AND POSSIBLY AS FAR SOUTH AS ARIZONA SOMETIME
NEXT WEEKEND. WIDESPREAD SLIGHT CHANCE POPS ARE IN THE FORECAST FOR
FRIDAY...AND MAY NEED TO RAMP UP POPS OVER THE NEXT FEW DAYS IF THE
TROUGH LOOKS LIKE IT WILL DIG FAR ENOUGH SOUTH INTO OUR AREA. EITHER
WAY IT IS FAIRLY LIKELY THIS LOW WILL USHER IN COOLER AND MUCH DRIER
AIR...AND POTENTIALLY ENDING OUR MONSOON SEASON.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...

THROUGH 19Z SAT...SCT-BKN CLDS AOA 10 THSD MSL. LIGHT WIND UNDER 8
KNOTS.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...

MAINLY CLEAR SKIES AND LIGHT WIND TO PREVAIL ACROSS THE AREA THROUGH
19Z SAT.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
RATHER DRY WESTERLY FLOW TO KEEP SKIES MAINLY CLEAR THROUGH THE
FORECAST PERIOD AT MOST LOCATIONS ACROSS THE REGION...WITH THE
EXCEPTION OF THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA...WHERE
LINGERING MOISTURE MAY ALLOW ISOLATED SHOWERS/THUNDERSTORMS TO
DEVELOP EACH AFTERNOON/EARLY EVENING. MINIMUM RELATIVE HUMIDITIES TO
FALL INTO THE 20 TO 30 PERCENT RANGE EACH AFTERNOON...WITH GOOD TO
EXCELLENT OVERNIGHT RECOVERIES. WINDS TO REMAIN MAINLY ON THE LIGHT
SIDE...MAINLY IN THE 5 TO 15 MPH RANGE...WITH THE USUAL DIURNAL
TRENDS TO PREVAIL AT MOST LOCATIONS.


&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...KUHLMAN
AVIATION...VASQUEZ
FIRE WEATHER...MEYERS/PERCHA













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