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000
FXUS65 KPSR 032020
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
120 PM MST TUE MAR 3 2015

.SYNOPSIS...
LOW PRESSURE...THAT WILL BE MOVING SLOWLY SOUTHWARD ACROSS THE
REGION...WILL KEEP THE WEATHER RATHER UNSETTLED AND COOL THROUGH
WEDNESDAY. A SLIGHT CHANCE OF SHOWERS...AND EVEN A FEW THUNDERSTORMS
CAN BE EXPECTED OVER SOUTH CENTRAL ARIZONA THROUGH TUESDAY EVENING.
A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY THURSDAY...INTO
THE WEEKEND AS HIGH PRESSURE SYSTEM BUILDS OVER THE DESERT
SOUTHWEST.

&&

.DISCUSSION...
UPPER LEVEL LOW PRESSURE TROF OVER THE DESERT SOUTHWEST...EXTENDING
SOUTHWESTWARD TO A POSITION JUST OFF THE CENTRAL BAJA CA
COAST...CONTINUED TO PUSH SLOWLY EAST-SOUTHEAST THIS AFTERNOON WITH
THE TROF AXIS STARTING TO PUSH INTO FAR WESTERN ARIZONA. LINGERING
BOUNDARY LAYER MOISTURE...WITH SURFACE DEWPOINTS ACROSS THE CENTRAL
DESERTS IN THE 40S...COMBINED WITH COOL AIR ALOFT TO ALLOW FOR
SIGNIFICANT CUMULUS DEVELOPMENT OVER THE LOWER DESERTS EARLY THIS
AFTERNOON. DYNAMICS WILL BE RATHER WEAK BUT THERE WILL CERTAINLY BE
A SLIGHT CHANCE FOR INSTABILITY SHOWERS OR EVEN A WEAK THUNDERSTORM
FOR THE REST OF THE AFTERNOON AND INTO THE EVENING HOURS FOR MOST
AREAS TO THE EAST OF THE LOWER COLORADO RIVER VALLEY. IN
FACT...RADAR AT 1 PM SHOWED ISOLATED SHOWERS MOVING ACROSS THE
CENTRAL DESERTS...AND ONE PUNY SHOWER ACTALLY PRODUCED BRIEF HEAVY
RAIN AT SKY HARBOR AIRPORT.

BY WEDNESDAY MORNING THE TROF AXIS IS FORECAST TO PUSH EAST OF THE
GREATER PHOENIX AREA ALLOWING FOR A DRIER AND MORE SUBSIDENT
NLY/NWLY FLOW ALOFT TO OVERSPREAD THE CENTRAL DESERTS AND CONFINE
ANY THREAT FOR SHOWERS OR STORMS TO THE HIGHER TERRAIN AREAS EAST OF
PHOENIX. WITH BOUNDARY LAYER MOISTURE REMAINING ELEVATED WEDNESDAY
MORNING...AND SIGNIFICANT CLEARING EXPECTED BY SUNRISE...THERE WILL
AGAIN BE THE POTENTIAL FOR FOG DEVELOPMENT. WE EXPECT LESS AREAL
COVERAGE OF THE FOG AND IT SHOULD NOT BE AS DENSE AS WHAT OCCURRED
THIS MORNING...BUT WE WILL MENTION PATCHY FOG FOR WED MORNING FROM
MARICOPA COUNTY EASTWARD. BY AFTERNOON WED WE SHOULD SOME FAIR
WEATHER CU OVER THE CENTRAL DESERTS...WITH SKIES MOSTLY SUNNY FROM
PHOENIX WESTWARD. WE WILL CALL FOR A SLIGHT CHANCE OF LINGERING
SHOWERS ACROSS ZONE 24 WITH THE THREAT ENDING BY EARLY EVENING
WEDNESDAY. HIGH TEMPS WILL CLIMB A FEW DEGREES AS THE AIRMASS WARMS
UP A BIT...BUT READINGS WILL REMAIN BELOW SEASONAL NORMALS.

THURSDAY...
A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET UP ACROSS THE
AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE CA COAST. THIS
WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING WITH HIGH TEMPS
REACHING INTO THE LOW TO MID 70S...AND TOWARDS SEASONAL NORMALS.

FRIDAY INTO EARLY NEXT WEEK...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A GOOD CHANCE FOR HIGHS NEAR 80 ACROSS THE LOWER
DESERTS BY THE WEEKEND...AND EVEN INTO THE MID 80S BY NEXT TUESDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
PLENTY OF LOW-LEVEL AND BOUNDARY LAYER MOISTURE REMAINS OVER THE
AREA AND WILL RESULT IN CONTINUED DEVELOPMENT OF CONGESTED CU FIELDS
THROUGH THE EARLY EVENING. UPPER TROUGH AXIS IS ALSO STILL MOVING
THROUGH THE AREA AND WILL ALLOW FOR SHOWER DEVELOPMENT TO POP-UP FOR
THE EVENING. ADDED VCSH MENTION FOR THE REMAINDER OF THE MIDDAY/AFTN
HOURS IN FOR THE PHX TERMINALS. WINDS WILL EVENTUALLY TRANSITION TO
AFTN SOUTHWEST-WEST HEADINGS WITH GNLY LIGHT SPEEDS. MORE ERRATIC
WINDS WITH LOCALIZED GUSTINESS WILL BE POSSIBLE DUE TO
VICINITY/PASSING SHOWERS AND ALONG WITH VERY SHORT WINDOWS OF VSBY
RESTRICTION/LOWERED CIGS.

BOUNDARY LAYER MOISTURE WILL REMAIN SOMEWHAT ELEVATED OVERNIGHT...SO
THERE IS A REMOTE POSSIBILITY OF PATCHY FOG IN THE AM. SOME DRYING
ACROSS THE PHX AREA THIS AFTERNOON SHOULD HELP KEEP THE CROSSOVER
TEMPERATURE AT KPHX AWAY FROM CRITICAL FOG THRESHOLDS FOR WED AM.
LOCAL SREF GUIDANCE HAS REMOTE CHANCES FOR REDUCED VSBYS AGAIN IN
THE AM. WILL HOLD OFF ANY RESTRICTIONS OR BR/FG INCLUSION IN TAFS
ATTM AS UNCERTAINTY IT HIGH FOR A TWO-MORNING-IN-A-ROW EVENT.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
NO AVIATION CONCERNS THROUGH WEDNESDAY MORNING WITH JUST OCCASIONAL
HIGH CLOUDS AND A FEW AFTERNOON CU TO DEAL WITH. SFC WINDS WILL
GENERALLY FAVOR A NORTHWEST DIRECTION...HOWEVER THE WEAK PRESSURE
GRADIENT MAY ALLOW EXTENDED PERIODS OF VARIABLE DIRECTION WITH
SPEEDS AOB 6 KT.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
STRONG HIGH PRESSURE WILL PROVIDE SEASONABLY WARM AND DRY CONDITIONS
TO THE DISTRICT DURING THE END OF OF THIS WEEK INTO EARLY NEXT WEEK.
WITH TEMPERATURES SLIGHTLY ABOVE NORMAL...AFTERNOON HUMIDITY LEVELS
WILL REGULARLY FALL INTO A 15 TO 25 PERCENT RANGE WITH GOOD
OVERNIGHT RECOVERY. WINDS WILL FAVOR A NORTH TO NORTHEAST TRAJECTORY
THROUGH THE PERIOD...WITH SOME OCCASIONAL GUSTINESS OVER RIDGE TOPS
BUT ALL IN ALL VERY TYPICAL SPEEDS. OVERALL...FIRE DANGER WILL BE
LIMITED DURING THIS TIME FRAME.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...PERCHA/CB
AVIATION...NOLTE/MO
FIRE WEATHER...MO




















000
FXUS65 KPSR 032020
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
120 PM MST TUE MAR 3 2015

.SYNOPSIS...
LOW PRESSURE...THAT WILL BE MOVING SLOWLY SOUTHWARD ACROSS THE
REGION...WILL KEEP THE WEATHER RATHER UNSETTLED AND COOL THROUGH
WEDNESDAY. A SLIGHT CHANCE OF SHOWERS...AND EVEN A FEW THUNDERSTORMS
CAN BE EXPECTED OVER SOUTH CENTRAL ARIZONA THROUGH TUESDAY EVENING.
A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY THURSDAY...INTO
THE WEEKEND AS HIGH PRESSURE SYSTEM BUILDS OVER THE DESERT
SOUTHWEST.

&&

.DISCUSSION...
UPPER LEVEL LOW PRESSURE TROF OVER THE DESERT SOUTHWEST...EXTENDING
SOUTHWESTWARD TO A POSITION JUST OFF THE CENTRAL BAJA CA
COAST...CONTINUED TO PUSH SLOWLY EAST-SOUTHEAST THIS AFTERNOON WITH
THE TROF AXIS STARTING TO PUSH INTO FAR WESTERN ARIZONA. LINGERING
BOUNDARY LAYER MOISTURE...WITH SURFACE DEWPOINTS ACROSS THE CENTRAL
DESERTS IN THE 40S...COMBINED WITH COOL AIR ALOFT TO ALLOW FOR
SIGNIFICANT CUMULUS DEVELOPMENT OVER THE LOWER DESERTS EARLY THIS
AFTERNOON. DYNAMICS WILL BE RATHER WEAK BUT THERE WILL CERTAINLY BE
A SLIGHT CHANCE FOR INSTABILITY SHOWERS OR EVEN A WEAK THUNDERSTORM
FOR THE REST OF THE AFTERNOON AND INTO THE EVENING HOURS FOR MOST
AREAS TO THE EAST OF THE LOWER COLORADO RIVER VALLEY. IN
FACT...RADAR AT 1 PM SHOWED ISOLATED SHOWERS MOVING ACROSS THE
CENTRAL DESERTS...AND ONE PUNY SHOWER ACTALLY PRODUCED BRIEF HEAVY
RAIN AT SKY HARBOR AIRPORT.

BY WEDNESDAY MORNING THE TROF AXIS IS FORECAST TO PUSH EAST OF THE
GREATER PHOENIX AREA ALLOWING FOR A DRIER AND MORE SUBSIDENT
NLY/NWLY FLOW ALOFT TO OVERSPREAD THE CENTRAL DESERTS AND CONFINE
ANY THREAT FOR SHOWERS OR STORMS TO THE HIGHER TERRAIN AREAS EAST OF
PHOENIX. WITH BOUNDARY LAYER MOISTURE REMAINING ELEVATED WEDNESDAY
MORNING...AND SIGNIFICANT CLEARING EXPECTED BY SUNRISE...THERE WILL
AGAIN BE THE POTENTIAL FOR FOG DEVELOPMENT. WE EXPECT LESS AREAL
COVERAGE OF THE FOG AND IT SHOULD NOT BE AS DENSE AS WHAT OCCURRED
THIS MORNING...BUT WE WILL MENTION PATCHY FOG FOR WED MORNING FROM
MARICOPA COUNTY EASTWARD. BY AFTERNOON WED WE SHOULD SOME FAIR
WEATHER CU OVER THE CENTRAL DESERTS...WITH SKIES MOSTLY SUNNY FROM
PHOENIX WESTWARD. WE WILL CALL FOR A SLIGHT CHANCE OF LINGERING
SHOWERS ACROSS ZONE 24 WITH THE THREAT ENDING BY EARLY EVENING
WEDNESDAY. HIGH TEMPS WILL CLIMB A FEW DEGREES AS THE AIRMASS WARMS
UP A BIT...BUT READINGS WILL REMAIN BELOW SEASONAL NORMALS.

THURSDAY...
A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET UP ACROSS THE
AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE CA COAST. THIS
WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING WITH HIGH TEMPS
REACHING INTO THE LOW TO MID 70S...AND TOWARDS SEASONAL NORMALS.

FRIDAY INTO EARLY NEXT WEEK...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A GOOD CHANCE FOR HIGHS NEAR 80 ACROSS THE LOWER
DESERTS BY THE WEEKEND...AND EVEN INTO THE MID 80S BY NEXT TUESDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
PLENTY OF LOW-LEVEL AND BOUNDARY LAYER MOISTURE REMAINS OVER THE
AREA AND WILL RESULT IN CONTINUED DEVELOPMENT OF CONGESTED CU FIELDS
THROUGH THE EARLY EVENING. UPPER TROUGH AXIS IS ALSO STILL MOVING
THROUGH THE AREA AND WILL ALLOW FOR SHOWER DEVELOPMENT TO POP-UP FOR
THE EVENING. ADDED VCSH MENTION FOR THE REMAINDER OF THE MIDDAY/AFTN
HOURS IN FOR THE PHX TERMINALS. WINDS WILL EVENTUALLY TRANSITION TO
AFTN SOUTHWEST-WEST HEADINGS WITH GNLY LIGHT SPEEDS. MORE ERRATIC
WINDS WITH LOCALIZED GUSTINESS WILL BE POSSIBLE DUE TO
VICINITY/PASSING SHOWERS AND ALONG WITH VERY SHORT WINDOWS OF VSBY
RESTRICTION/LOWERED CIGS.

BOUNDARY LAYER MOISTURE WILL REMAIN SOMEWHAT ELEVATED OVERNIGHT...SO
THERE IS A REMOTE POSSIBILITY OF PATCHY FOG IN THE AM. SOME DRYING
ACROSS THE PHX AREA THIS AFTERNOON SHOULD HELP KEEP THE CROSSOVER
TEMPERATURE AT KPHX AWAY FROM CRITICAL FOG THRESHOLDS FOR WED AM.
LOCAL SREF GUIDANCE HAS REMOTE CHANCES FOR REDUCED VSBYS AGAIN IN
THE AM. WILL HOLD OFF ANY RESTRICTIONS OR BR/FG INCLUSION IN TAFS
ATTM AS UNCERTAINTY IT HIGH FOR A TWO-MORNING-IN-A-ROW EVENT.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
NO AVIATION CONCERNS THROUGH WEDNESDAY MORNING WITH JUST OCCASIONAL
HIGH CLOUDS AND A FEW AFTERNOON CU TO DEAL WITH. SFC WINDS WILL
GENERALLY FAVOR A NORTHWEST DIRECTION...HOWEVER THE WEAK PRESSURE
GRADIENT MAY ALLOW EXTENDED PERIODS OF VARIABLE DIRECTION WITH
SPEEDS AOB 6 KT.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
STRONG HIGH PRESSURE WILL PROVIDE SEASONABLY WARM AND DRY CONDITIONS
TO THE DISTRICT DURING THE END OF OF THIS WEEK INTO EARLY NEXT WEEK.
WITH TEMPERATURES SLIGHTLY ABOVE NORMAL...AFTERNOON HUMIDITY LEVELS
WILL REGULARLY FALL INTO A 15 TO 25 PERCENT RANGE WITH GOOD
OVERNIGHT RECOVERY. WINDS WILL FAVOR A NORTH TO NORTHEAST TRAJECTORY
THROUGH THE PERIOD...WITH SOME OCCASIONAL GUSTINESS OVER RIDGE TOPS
BUT ALL IN ALL VERY TYPICAL SPEEDS. OVERALL...FIRE DANGER WILL BE
LIMITED DURING THIS TIME FRAME.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...PERCHA/CB
AVIATION...NOLTE/MO
FIRE WEATHER...MO



















000
FXUS65 KPSR 031959
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1258 PM MST TUE MAR 3 2015

.UPDATE...TO AVIATION DISCUSSION.

&&

.SYNOPSIS...
LOW PRESSURE...THAT WILL BE MOVING SLOWLY SOUTHWARD ACROSS THE
REGION...WILL KEEP THE WEATHER RATHER UNSETTLED AND COOL THROUGH
WEDNESDAY. A SLIGHT CHANCE OF SHOWERS...AND EVEN A FEW THUNDERSTORMS
CAN BE EXPECTED OVER SOUTH CENTRAL ARIZONA THROUGH TUESDAY EVENING.
A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY THURSDAY...INTO
THE WEEKEND AS HIGH PRESSURE SYSTEM BUILDS OVER THE DESERT
SOUTHWEST.

&&

.DISCUSSION...
INTERESTING WEATHER THIS MORNING AS PATCHY DENSE FOG DEVELOPED
ACROSS PORTIONS OF THE GREATER PHOENIX METROPOLITAN AREA...AND MUCH
OF NORTHWEST PINAL COUNTY. A TROF OF LOW PRESSURE CONTINUED TO SAG
SOUTHEAST ACROSS THE DESERT SOUTHWEST WITH THE TROF AXIS RUNNING
NE-SW ACROSS FAR SERN CA/SRN NEVADA. ORIENTATION OF THE TROF PLACED
A WEAK SWLY FLOW ACROSS THE LOWER DESERTS WHICH CONTINUED TO ADVECT
IN MODEST AMOUNTS OF MOISTURE. OVERALL MOISTURE VALUES ARE LESS THAN
24 HOURS AGO...WITH PWAT VALUES RUNNING AROUND ONE HALF INCH...BUT
THE BOUNDARY LAYER REMAINS QUITE MOIST. SURFACE DEWPOINTS ACROSS THE
CENTRAL DESERTS WERE RUNNING IN THE MID TO UPPER 40S AT 9 AM. SOME
UNEXPECTED CLEARING EARLY THIS MORNING ALLOWED SURFACE TEMPS TO FALL
OFF AND REACH THE CROSSOVER TEMPERATURE AND AS SUCH PATCHY DENSE FOG
DEVELOPED IN THE GREATER PHOENIX AREA...DROPPING VIS AT SKY HARBOR
TO 1/4 MILE. OTHER AREAS...NEAR SOUTH MOUNTAIN...ALONG INTERSTATE 8
AND THE SALT RIVER BED...AND ESPECIALLY SOUTHEAST OF THE VALLEY IN
CASA GRANDE...SAW LOCALLY DENSE FOG WITH VIS VALUES DOWN AT OR BELOW
1/4 MILE. WE ISSUED A DENSE FOG ADVISORY FOR ZONE 28 EFFECTIVE UNTIL
10 AM.

FOR THE REST OF TODAY...THE FOG WILL GRADUALLY ERODE UNDER THE
INFLUENCE OF INCREASING SUN/MIXING...AND WE WILL SEE PARTLY CLOUDY
SKIES THROUGH THE AFTERNOON. AS THE TROF AXIS SLOWLY MOVES IN FROM
THE WEST TODAY AND THIS EVENING THERE WILL BE SUFFICIENT INSTABILITY
TO ALLOW FOR A SLIGHT CHANCE OF SHOWERS OR AFTERNOON THUNDERSTORMS.
DYNAMICS ARE RATHER WEAK...AS THE WIND FIELDS ASSOCIATED WITH THE
PASSING TROF ARE NOT VERY IMPRESSIVE...SO ANY STORM THAT DEVELOPS
WILL BE ON THE WEAK SIDE AS WELL. FORECASTS HAVE BEEN TWEAKED FOR
CURRENT SKY AND WEATHER TRENDS AND ARE IN GOOD SHAPE FOR NOW.

.PREVIOUS DISCUSSION...
TODAY THROUGH WEDNESDAY...
AFTER A RATHER WET AND COOL MONDAY...WITH SOME OF THE MOST FAVORED
AREAS ACROSS NORTHERN MARICOPA COUNTY SEEING UP TO AN INCH OF
RAIN...TODAY LOOKS LIKE IT WILL BE A QUIETER ONE...AS THE UPPER TROF
THAT BROUGHT US ALL THE RAIN AND CLOUDS HAS NOW MOVED OFF WELL TO
OUR EAST...INTO THE CENTRAL PLAINS.

HOWEVER...THE WEATHER TODAY AND TONIGHT STILL LOOKS LIKE IT WILL BE
RATHER UNSETTLED...WITH ISOLATED-TO-SCATTERED SHOWERS TO CONTINUE
OVER SOUTH-CENTRAL ARIZONA...ESPECIALLY OVER THE HIGHER TERRAIN
NORTH AND EAST OF PHOENIX. THIS CONTINUATION OF SHOWER CHANCES IS
DUE TO A COMBINATION OF MOIST SOUTHWESTERLY FLOW ALOFT THAT IS BEING
GENERATED BY ANOTHER UPPER LOW CENTER THAT IS NOW POSITIONED OFF THE
SOUTHERN CA COAST THIS MORNING...AND A COUPLE OF WEAK SHORTWAVES
THAT WILL BE DROPPING SOUTHWARD ACROSS AZ AS THE STRONG LONG-WAVE
UPPER TROF THEY ARE EMBEDDED IN MOVES SOUTHEASTWARD ACROSS THE
CENTRAL ROCKIES INTO THE CENTRAL PLAINS. ALTHOUGH MOISTURE LEVELS
THROUGH THE COLUMN LOOK TO BE RATHER LIMITED...WITH PWATS IN THE
0.50-0.60 INCH RANGE...THERE APPEARS THAT THERE WILL BE ENOUGH
DYNAMICS/INSTABILITY TO TRIGGER LIGHT SHOWERS...AND EVEN ONE OR TWO
THUNDERSTORMS TODAY AND TONIGHT AS THE SHORTWAVES PASS ACROSS THE
REGION...WITH PERHAPS A TENTH OF AN INCH OR SO OF RAIN FALLING FROM
THE HEAVIER SHOWERS...AND EVEN A DUSTING OF SNOW OVER OUR HIGHEST
PEAKS. TEMPERATURES ARE EXPECTED TO REMAIN BELOW NORMAL TODAY...WITH
850MB TEMPERATURES AROUND 5C KEEPING LOWER DESERT HIGHS DOWN IN THE
60S AND LOW 70S...IN SPITE OF CONSIDERABLE SUNSHINE. THE CHANCES FOR
PRECIP WILL PRETTY MUCH END BY MIDDAY ON WEDNESDAY AS THE UPPER LOW
THAT IS NOW OFF THE SOUTHERN CA COAST MOVES OFF WELL TO OUR SOUTH
AND EAST...CUTTING OFF THE MOISTURE FEED FROM THE PACIFIC...AND
RIDGING BEGINS TO BUILD IN FROM THE WEST BEHIND THE MAIN LONG-WAVE
TROF.

THURSDAY...

A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO EARLY NEXT WEEK...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A GOOD CHANCE FOR HIGHS NEAR 80 ACROSS THE LOWER
DESERTS BY THE WEEKEND...AND EVEN INTO THE MID 80S BY NEXT TUESDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
PLENTY OF LOW-LEVEL AND BOUNDARY LAYER MOISTURE REMAINS OVER THE
AREA AND WILL RESULT IN CONTINUED DEVELOPMENT OF CONGESTED CU FIELDS
THROUGH THE EARLY EVENING. UPPER TROUGH AXIS IS ALSO STILL MOVING
THROUGH THE AREA AND WILL ALLOW FOR SHOWER DEVELOPMENT TO POP-UP FOR
THE EVENING. ADDED VCSH MENTION FOR THE REMAINDER OF THE MIDDAY/AFTN
HOURS IN FOR THE PHX TERMINALS. WINDS WILL EVENTUALLY TRANSITION TO
AFTN SOUTHWEST-WEST HEADINGS WITH GNLY LIGHT SPEEDS. MORE ERRATIC
WINDS WITH LOCALIZED GUSTINESS WILL BE POSSIBLE DUE TO
VICINITY/PASSING SHOWERS AND ALONG WITH VERY SHORT WINDOWS OF VSBY
RESTRICTION/LOWERED CIGS.

BOUNDARY LAYER MOISTURE WILL REMAIN SOMEWHAT ELEVATED OVERNIGHT...SO
THERE IS A REMOTE POSSIBILITY OF PATCHY FOG IN THE AM. SOME DRYING
ACROSS THE PHX AREA THIS AFTERNOON SHOULD HELP KEEP THE CROSSOVER
TEMPERATURE AT KPHX AWAY FROM CRITICAL FOG THRESHOLDS FOR WED AM.
LOCAL SREF GUIDANCE HAS REMOTE CHANCES FOR REDUCED VSBYS AGAIN IN
THE AM. WILL HOLD OFF ANY RESTRICTIONS OR BR/FG INCLUSION IN TAFS
ATTM AS UNCERTAINTY IT HIGH FOR A TWO-MORNING-IN-A-ROW EVENT.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
NO AVIATION CONCERNS THROUGH WEDNESDAY MORNING WITH JUST OCCASIONAL
HIGH CLOUDS AND A FEW AFTERNOON CU TO DEAL WITH. SFC WINDS WILL
GENERALLY FAVOR A NORTHWEST DIRECTION...HOWEVER THE WEAK PRESSURE
GRADIENT MAY ALLOW EXTENDED PERIODS OF VARIABLE DIRECTION WITH
SPEEDS AOB 6 KT.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
STRONG HIGH PRESSURE WILL PROVIDE SEASONABLY WARM AND DRY CONDITIONS
TO THE DISTRICT DURING THE END OF OF THIS WEEK INTO EARLY NEXT WEEK.
WITH TEMPERATURES SLIGHTLY ABOVE NORMAL...AFTERNOON HUMIDITY LEVELS
WILL REGULARLY FALL INTO A 15 TO 25 PERCENT RANGE WITH GOOD
OVERNIGHT RECOVERY. WINDS WILL FAVOR A NORTH TO NORTHEAST TRAJECTORY
THROUGH THE PERIOD...WITH SOME OCCASIONAL GUSTINESS OVER RIDGE TOPS
BUT ALL IN ALL VERY TYPICAL SPEEDS. OVERALL...FIRE DANGER WILL BE
LIMITED DURING THIS TIME FRAME.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...PERCHA/CB
AVIATION...NOLTE/MO
FIRE WEATHER...MO
















000
FXUS65 KPSR 031959
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1258 PM MST TUE MAR 3 2015

.UPDATE...TO AVIATION DISCUSSION.

&&

.SYNOPSIS...
LOW PRESSURE...THAT WILL BE MOVING SLOWLY SOUTHWARD ACROSS THE
REGION...WILL KEEP THE WEATHER RATHER UNSETTLED AND COOL THROUGH
WEDNESDAY. A SLIGHT CHANCE OF SHOWERS...AND EVEN A FEW THUNDERSTORMS
CAN BE EXPECTED OVER SOUTH CENTRAL ARIZONA THROUGH TUESDAY EVENING.
A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY THURSDAY...INTO
THE WEEKEND AS HIGH PRESSURE SYSTEM BUILDS OVER THE DESERT
SOUTHWEST.

&&

.DISCUSSION...
INTERESTING WEATHER THIS MORNING AS PATCHY DENSE FOG DEVELOPED
ACROSS PORTIONS OF THE GREATER PHOENIX METROPOLITAN AREA...AND MUCH
OF NORTHWEST PINAL COUNTY. A TROF OF LOW PRESSURE CONTINUED TO SAG
SOUTHEAST ACROSS THE DESERT SOUTHWEST WITH THE TROF AXIS RUNNING
NE-SW ACROSS FAR SERN CA/SRN NEVADA. ORIENTATION OF THE TROF PLACED
A WEAK SWLY FLOW ACROSS THE LOWER DESERTS WHICH CONTINUED TO ADVECT
IN MODEST AMOUNTS OF MOISTURE. OVERALL MOISTURE VALUES ARE LESS THAN
24 HOURS AGO...WITH PWAT VALUES RUNNING AROUND ONE HALF INCH...BUT
THE BOUNDARY LAYER REMAINS QUITE MOIST. SURFACE DEWPOINTS ACROSS THE
CENTRAL DESERTS WERE RUNNING IN THE MID TO UPPER 40S AT 9 AM. SOME
UNEXPECTED CLEARING EARLY THIS MORNING ALLOWED SURFACE TEMPS TO FALL
OFF AND REACH THE CROSSOVER TEMPERATURE AND AS SUCH PATCHY DENSE FOG
DEVELOPED IN THE GREATER PHOENIX AREA...DROPPING VIS AT SKY HARBOR
TO 1/4 MILE. OTHER AREAS...NEAR SOUTH MOUNTAIN...ALONG INTERSTATE 8
AND THE SALT RIVER BED...AND ESPECIALLY SOUTHEAST OF THE VALLEY IN
CASA GRANDE...SAW LOCALLY DENSE FOG WITH VIS VALUES DOWN AT OR BELOW
1/4 MILE. WE ISSUED A DENSE FOG ADVISORY FOR ZONE 28 EFFECTIVE UNTIL
10 AM.

FOR THE REST OF TODAY...THE FOG WILL GRADUALLY ERODE UNDER THE
INFLUENCE OF INCREASING SUN/MIXING...AND WE WILL SEE PARTLY CLOUDY
SKIES THROUGH THE AFTERNOON. AS THE TROF AXIS SLOWLY MOVES IN FROM
THE WEST TODAY AND THIS EVENING THERE WILL BE SUFFICIENT INSTABILITY
TO ALLOW FOR A SLIGHT CHANCE OF SHOWERS OR AFTERNOON THUNDERSTORMS.
DYNAMICS ARE RATHER WEAK...AS THE WIND FIELDS ASSOCIATED WITH THE
PASSING TROF ARE NOT VERY IMPRESSIVE...SO ANY STORM THAT DEVELOPS
WILL BE ON THE WEAK SIDE AS WELL. FORECASTS HAVE BEEN TWEAKED FOR
CURRENT SKY AND WEATHER TRENDS AND ARE IN GOOD SHAPE FOR NOW.

.PREVIOUS DISCUSSION...
TODAY THROUGH WEDNESDAY...
AFTER A RATHER WET AND COOL MONDAY...WITH SOME OF THE MOST FAVORED
AREAS ACROSS NORTHERN MARICOPA COUNTY SEEING UP TO AN INCH OF
RAIN...TODAY LOOKS LIKE IT WILL BE A QUIETER ONE...AS THE UPPER TROF
THAT BROUGHT US ALL THE RAIN AND CLOUDS HAS NOW MOVED OFF WELL TO
OUR EAST...INTO THE CENTRAL PLAINS.

HOWEVER...THE WEATHER TODAY AND TONIGHT STILL LOOKS LIKE IT WILL BE
RATHER UNSETTLED...WITH ISOLATED-TO-SCATTERED SHOWERS TO CONTINUE
OVER SOUTH-CENTRAL ARIZONA...ESPECIALLY OVER THE HIGHER TERRAIN
NORTH AND EAST OF PHOENIX. THIS CONTINUATION OF SHOWER CHANCES IS
DUE TO A COMBINATION OF MOIST SOUTHWESTERLY FLOW ALOFT THAT IS BEING
GENERATED BY ANOTHER UPPER LOW CENTER THAT IS NOW POSITIONED OFF THE
SOUTHERN CA COAST THIS MORNING...AND A COUPLE OF WEAK SHORTWAVES
THAT WILL BE DROPPING SOUTHWARD ACROSS AZ AS THE STRONG LONG-WAVE
UPPER TROF THEY ARE EMBEDDED IN MOVES SOUTHEASTWARD ACROSS THE
CENTRAL ROCKIES INTO THE CENTRAL PLAINS. ALTHOUGH MOISTURE LEVELS
THROUGH THE COLUMN LOOK TO BE RATHER LIMITED...WITH PWATS IN THE
0.50-0.60 INCH RANGE...THERE APPEARS THAT THERE WILL BE ENOUGH
DYNAMICS/INSTABILITY TO TRIGGER LIGHT SHOWERS...AND EVEN ONE OR TWO
THUNDERSTORMS TODAY AND TONIGHT AS THE SHORTWAVES PASS ACROSS THE
REGION...WITH PERHAPS A TENTH OF AN INCH OR SO OF RAIN FALLING FROM
THE HEAVIER SHOWERS...AND EVEN A DUSTING OF SNOW OVER OUR HIGHEST
PEAKS. TEMPERATURES ARE EXPECTED TO REMAIN BELOW NORMAL TODAY...WITH
850MB TEMPERATURES AROUND 5C KEEPING LOWER DESERT HIGHS DOWN IN THE
60S AND LOW 70S...IN SPITE OF CONSIDERABLE SUNSHINE. THE CHANCES FOR
PRECIP WILL PRETTY MUCH END BY MIDDAY ON WEDNESDAY AS THE UPPER LOW
THAT IS NOW OFF THE SOUTHERN CA COAST MOVES OFF WELL TO OUR SOUTH
AND EAST...CUTTING OFF THE MOISTURE FEED FROM THE PACIFIC...AND
RIDGING BEGINS TO BUILD IN FROM THE WEST BEHIND THE MAIN LONG-WAVE
TROF.

THURSDAY...

A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO EARLY NEXT WEEK...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A GOOD CHANCE FOR HIGHS NEAR 80 ACROSS THE LOWER
DESERTS BY THE WEEKEND...AND EVEN INTO THE MID 80S BY NEXT TUESDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
PLENTY OF LOW-LEVEL AND BOUNDARY LAYER MOISTURE REMAINS OVER THE
AREA AND WILL RESULT IN CONTINUED DEVELOPMENT OF CONGESTED CU FIELDS
THROUGH THE EARLY EVENING. UPPER TROUGH AXIS IS ALSO STILL MOVING
THROUGH THE AREA AND WILL ALLOW FOR SHOWER DEVELOPMENT TO POP-UP FOR
THE EVENING. ADDED VCSH MENTION FOR THE REMAINDER OF THE MIDDAY/AFTN
HOURS IN FOR THE PHX TERMINALS. WINDS WILL EVENTUALLY TRANSITION TO
AFTN SOUTHWEST-WEST HEADINGS WITH GNLY LIGHT SPEEDS. MORE ERRATIC
WINDS WITH LOCALIZED GUSTINESS WILL BE POSSIBLE DUE TO
VICINITY/PASSING SHOWERS AND ALONG WITH VERY SHORT WINDOWS OF VSBY
RESTRICTION/LOWERED CIGS.

BOUNDARY LAYER MOISTURE WILL REMAIN SOMEWHAT ELEVATED OVERNIGHT...SO
THERE IS A REMOTE POSSIBILITY OF PATCHY FOG IN THE AM. SOME DRYING
ACROSS THE PHX AREA THIS AFTERNOON SHOULD HELP KEEP THE CROSSOVER
TEMPERATURE AT KPHX AWAY FROM CRITICAL FOG THRESHOLDS FOR WED AM.
LOCAL SREF GUIDANCE HAS REMOTE CHANCES FOR REDUCED VSBYS AGAIN IN
THE AM. WILL HOLD OFF ANY RESTRICTIONS OR BR/FG INCLUSION IN TAFS
ATTM AS UNCERTAINTY IT HIGH FOR A TWO-MORNING-IN-A-ROW EVENT.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
NO AVIATION CONCERNS THROUGH WEDNESDAY MORNING WITH JUST OCCASIONAL
HIGH CLOUDS AND A FEW AFTERNOON CU TO DEAL WITH. SFC WINDS WILL
GENERALLY FAVOR A NORTHWEST DIRECTION...HOWEVER THE WEAK PRESSURE
GRADIENT MAY ALLOW EXTENDED PERIODS OF VARIABLE DIRECTION WITH
SPEEDS AOB 6 KT.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
STRONG HIGH PRESSURE WILL PROVIDE SEASONABLY WARM AND DRY CONDITIONS
TO THE DISTRICT DURING THE END OF OF THIS WEEK INTO EARLY NEXT WEEK.
WITH TEMPERATURES SLIGHTLY ABOVE NORMAL...AFTERNOON HUMIDITY LEVELS
WILL REGULARLY FALL INTO A 15 TO 25 PERCENT RANGE WITH GOOD
OVERNIGHT RECOVERY. WINDS WILL FAVOR A NORTH TO NORTHEAST TRAJECTORY
THROUGH THE PERIOD...WITH SOME OCCASIONAL GUSTINESS OVER RIDGE TOPS
BUT ALL IN ALL VERY TYPICAL SPEEDS. OVERALL...FIRE DANGER WILL BE
LIMITED DURING THIS TIME FRAME.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...PERCHA/CB
AVIATION...NOLTE/MO
FIRE WEATHER...MO

















000
FXUS65 KPSR 031625
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
925 AM MST TUE MAR 3 2015

.SYNOPSIS...
LOW PRESSURE...THAT WILL BE MOVING SLOWLY SOUTHWARD ACROSS THE
REGION...WILL KEEP THE WEATHER RATHER UNSETTLED AND COOL THROUGH
WEDNESDAY. A SLIGHT CHANCE OF SHOWERS...AND EVEN A FEW THUNDERSTORMS
CAN BE EXPECTED OVER SOUTH CENTRAL ARIZONA THROUGH TUESDAY EVENING.
A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY THURSDAY...INTO
THE WEEKEND AS HIGH PRESSURE SYSTEM BUILDS OVER THE DESERT
SOUTHWEST.

&&

.DISCUSSION...
INTERESTING WEATHER THIS MORNING AS PATCHY DENSE FOG DEVELOPED
ACROSS PORTIONS OF THE GREATER PHOENIX METROPOLITAN AREA...AND MUCH
OF NORTHWEST PINAL COUNTY. A TROF OF LOW PRESSURE CONTINUED TO SAG
SOUTHEAST ACROSS THE DESERT SOUTHWEST WITH THE TROF AXIS RUNNING
NE-SW ACROSS FAR SERN CA/SRN NEVADA. ORIENTATION OF THE TROF PLACED
A WEAK SWLY FLOW ACROSS THE LOWER DESERTS WHICH CONTINUED TO ADVECT
IN MODEST AMOUNTS OF MOISTURE. OVERALL MOISTURE VALUES ARE LESS THAN
24 HOURS AGO...WITH PWAT VALUES RUNNING AROUND ONE HALF INCH...BUT
THE BOUNDARY LAYER REMAINS QUITE MOIST. SURFACE DEWPOINTS ACROSS THE
CENTRAL DESERTS WERE RUNNING IN THE MID TO UPPER 40S AT 9 AM. SOME
UNEXPECTED CLEARING EARLY THIS MORNING ALLOWED SURFACE TEMPS TO FALL
OFF AND REACH THE CROSSOVER TEMPERATURE AND AS SUCH PATCHY DENSE FOG
DEVELOPED IN THE GREATER PHOENIX AREA...DROPPING VIS AT SKY HARBOR
TO 1/4 MILE. OTHER AREAS...NEAR SOUTH MOUNTAIN...ALONG INTERSTATE 8
AND THE SALT RIVER BED...AND ESPECIALLY SOUTHEAST OF THE VALLEY IN
CASA GRANDE...SAW LOCALLY DENSE FOG WITH VIS VALUES DOWN AT OR BELOW
1/4 MILE. WE ISSUED A DENSE FOG ADVISORY FOR ZONE 28 EFFECTIVE UNTIL
10 AM.

FOR THE REST OF TODAY...THE FOG WILL GRADUALLY ERODE UNDER THE
INFLUENCE OF INCREASING SUN/MIXING...AND WE WILL SEE PARTLY CLOUDY
SKIES THROUGH THE AFTERNOON. AS THE TROF AXIS SLOWLY MOVES IN FROM
THE WEST TODAY AND THIS EVENING THERE WILL BE SUFFICIENT INSTABILITY
TO ALLOW FOR A SLIGHT CHANCE OF SHOWERS OR AFTERNOON THUNDERSTORMS.
DYNAMICS ARE RATHER WEAK...AS THE WIND FIELDS ASSOCIATED WITH THE
PASSING TROF ARE NOT VERY IMPRESSIVE...SO ANY STORM THAT DEVELOPS
WILL BE ON THE WEAK SIDE AS WELL. FORECASTS HAVE BEEN TWEAKED FOR
CURRENT SKY AND WEATHER TRENDS AND ARE IN GOOD SHAPE FOR NOW.

.PREVIOUS DISCUSSION...
TODAY THROUGH WEDNESDAY...
AFTER A RATHER WET AND COOL MONDAY...WITH SOME OF THE MOST FAVORED
AREAS ACROSS NORTHERN MARICOPA COUNTY SEEING UP TO AN INCH OF
RAIN...TODAY LOOKS LIKE IT WILL BE A QUIETER ONE...AS THE UPPER TROF
THAT BROUGHT US ALL THE RAIN AND CLOUDS HAS NOW MOVED OFF WELL TO
OUR EAST...INTO THE CENTRAL PLAINS.

HOWEVER...THE WEATHER TODAY AND TONIGHT STILL LOOKS LIKE IT WILL BE
RATHER UNSETTLED...WITH ISOLATED-TO-SCATTERED SHOWERS TO CONTINUE
OVER SOUTH-CENTRAL ARIZONA...ESPECIALLY OVER THE HIGHER TERRAIN
NORTH AND EAST OF PHOENIX. THIS CONTINUATION OF SHOWER CHANCES IS
DUE TO A COMBINATION OF MOIST SOUTHWESTERLY FLOW ALOFT THAT IS BEING
GENERATED BY ANOTHER UPPER LOW CENTER THAT IS NOW POSITIONED OFF THE
SOUTHERN CA COAST THIS MORNING...AND A COUPLE OF WEAK SHORTWAVES
THAT WILL BE DROPPING SOUTHWARD ACROSS AZ AS THE STRONG LONG-WAVE
UPPER TROF THEY ARE EMBEDDED IN MOVES SOUTHEASTWARD ACROSS THE
CENTRAL ROCKIES INTO THE CENTRAL PLAINS. ALTHOUGH MOISTURE LEVELS
THROUGH THE COLUMN LOOK TO BE RATHER LIMITED...WITH PWATS IN THE
0.50-0.60 INCH RANGE...THERE APPEARS THAT THERE WILL BE ENOUGH
DYNAMICS/INSTABILITY TO TRIGGER LIGHT SHOWERS...AND EVEN ONE OR TWO
THUNDERSTORMS TODAY AND TONIGHT AS THE SHORTWAVES PASS ACROSS THE
REGION...WITH PERHAPS A TENTH OF AN INCH OR SO OF RAIN FALLING FROM
THE HEAVIER SHOWERS...AND EVEN A DUSTING OF SNOW OVER OUR HIGHEST
PEAKS. TEMPERATURES ARE EXPECTED TO REMAIN BELOW NORMAL TODAY...WITH
850MB TEMPERATURES AROUND 5C KEEPING LOWER DESERT HIGHS DOWN IN THE
60S AND LOW 70S...IN SPITE OF CONSIDERABLE SUNSHINE. THE CHANCES FOR
PRECIP WILL PRETTY MUCH END BY MIDDAY ON WEDNESDAY AS THE UPPER LOW
THAT IS NOW OFF THE SOUTHERN CA COAST MOVES OFF WELL TO OUR SOUTH
AND EAST...CUTTING OFF THE MOISTURE FEED FROM THE PACIFIC...AND
RIDGING BEGINS TO BUILD IN FROM THE WEST BEHIND THE MAIN LONG-WAVE
TROF.

THURSDAY...

A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO EARLY NEXT WEEK...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A GOOD CHANCE FOR HIGHS NEAR 80 ACROSS THE LOWER
DESERTS BY THE WEEKEND...AND EVEN INTO THE MID 80S BY NEXT TUESDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
LOCALIZED AND PATCHY FOG DEVELOPMENT WILL CONTINUE TO FAVOR AREAS OF
THE SOUTHEAST PHX METRO AND NW PINAL COUNTY THROUGH THE MORNING...AT
TIMES GENERATING LOCALLY DENSE VSBYS INTO IFR VALUES. ANOTHER ROUND
OF MID TO HIGH LEVEL CLOUDS WILL APPROACH FROM THE SOUTHWEST...WHICH
SHOULD HELP MITIGATE FURTHER FOG DEVELOPMENT THIS MORNING. CANNOT
RULE OUT ISOLATED SHOWER DEVELOP LATER INTO THE DAY/AFTERNOON WITH
THE UPPER TROUGH AXIS STILL OVERHEAD AND ABUNDANT LOW-LEVEL MOISTURE
STILL PREVALENT. HOWEVER...WILL NOT INCLUDE MENTION IN THE TAFS THIS
TIME UNTIL COVERAGE PICKS UP ON AREA RADARS. SFC WINDS WILL REMAIN
LIGHT THROUGH WEDNESDAY MORNING...AND TYPICAL OVERNIGHT SHIFT TO AN
EASTERLY DIRECTION MAY BE VERY DELAYED OR NON-EXISTENT LATE TONIGHT.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
NO AVIATION CONCERNS THROUGH WEDNESDAY MORNING WITH JUST OCCASIONAL
HIGH CLOUDS AND A FEW AFTERNOON CU TO DEAL WITH. SFC WINDS WILL
GENERALLY FAVOR A NORTHWEST DIRECTION...HOWEVER THE WEAK PRESSURE
GRADIENT MAY ALLOW EXTENDED PERIODS OF VARIABLE DIRECTION WITH
SPEEDS AOB 6 KT.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
STRONG HIGH PRESSURE WILL PROVIDE SEASONABLY WARM AND DRY CONDITIONS
TO THE DISTRICT DURING THE END OF OF THIS WEEK INTO EARLY NEXT WEEK.
WITH TEMPERATURES SLIGHTLY ABOVE NORMAL...AFTERNOON HUMIDITY LEVELS
WILL REGULARLY FALL INTO A 15 TO 25 PERCENT RANGE WITH GOOD
OVERNIGHT RECOVERY. WINDS WILL FAVOR A NORTH TO NORTHEAST TRAJECTORY
THROUGH THE PERIOD...WITH SOME OCCASIONAL GUSTINESS OVER RIDGE TOPS
BUT ALL IN ALL VERY TYPICAL SPEEDS. OVERALL...FIRE DANGER WILL BE
LIMITED DURING THIS TIME FRAME.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...PERCHA/CB
AVIATION...NOLTE/MO
FIRE WEATHER...MO














000
FXUS65 KPSR 031625
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
925 AM MST TUE MAR 3 2015

.SYNOPSIS...
LOW PRESSURE...THAT WILL BE MOVING SLOWLY SOUTHWARD ACROSS THE
REGION...WILL KEEP THE WEATHER RATHER UNSETTLED AND COOL THROUGH
WEDNESDAY. A SLIGHT CHANCE OF SHOWERS...AND EVEN A FEW THUNDERSTORMS
CAN BE EXPECTED OVER SOUTH CENTRAL ARIZONA THROUGH TUESDAY EVENING.
A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY THURSDAY...INTO
THE WEEKEND AS HIGH PRESSURE SYSTEM BUILDS OVER THE DESERT
SOUTHWEST.

&&

.DISCUSSION...
INTERESTING WEATHER THIS MORNING AS PATCHY DENSE FOG DEVELOPED
ACROSS PORTIONS OF THE GREATER PHOENIX METROPOLITAN AREA...AND MUCH
OF NORTHWEST PINAL COUNTY. A TROF OF LOW PRESSURE CONTINUED TO SAG
SOUTHEAST ACROSS THE DESERT SOUTHWEST WITH THE TROF AXIS RUNNING
NE-SW ACROSS FAR SERN CA/SRN NEVADA. ORIENTATION OF THE TROF PLACED
A WEAK SWLY FLOW ACROSS THE LOWER DESERTS WHICH CONTINUED TO ADVECT
IN MODEST AMOUNTS OF MOISTURE. OVERALL MOISTURE VALUES ARE LESS THAN
24 HOURS AGO...WITH PWAT VALUES RUNNING AROUND ONE HALF INCH...BUT
THE BOUNDARY LAYER REMAINS QUITE MOIST. SURFACE DEWPOINTS ACROSS THE
CENTRAL DESERTS WERE RUNNING IN THE MID TO UPPER 40S AT 9 AM. SOME
UNEXPECTED CLEARING EARLY THIS MORNING ALLOWED SURFACE TEMPS TO FALL
OFF AND REACH THE CROSSOVER TEMPERATURE AND AS SUCH PATCHY DENSE FOG
DEVELOPED IN THE GREATER PHOENIX AREA...DROPPING VIS AT SKY HARBOR
TO 1/4 MILE. OTHER AREAS...NEAR SOUTH MOUNTAIN...ALONG INTERSTATE 8
AND THE SALT RIVER BED...AND ESPECIALLY SOUTHEAST OF THE VALLEY IN
CASA GRANDE...SAW LOCALLY DENSE FOG WITH VIS VALUES DOWN AT OR BELOW
1/4 MILE. WE ISSUED A DENSE FOG ADVISORY FOR ZONE 28 EFFECTIVE UNTIL
10 AM.

FOR THE REST OF TODAY...THE FOG WILL GRADUALLY ERODE UNDER THE
INFLUENCE OF INCREASING SUN/MIXING...AND WE WILL SEE PARTLY CLOUDY
SKIES THROUGH THE AFTERNOON. AS THE TROF AXIS SLOWLY MOVES IN FROM
THE WEST TODAY AND THIS EVENING THERE WILL BE SUFFICIENT INSTABILITY
TO ALLOW FOR A SLIGHT CHANCE OF SHOWERS OR AFTERNOON THUNDERSTORMS.
DYNAMICS ARE RATHER WEAK...AS THE WIND FIELDS ASSOCIATED WITH THE
PASSING TROF ARE NOT VERY IMPRESSIVE...SO ANY STORM THAT DEVELOPS
WILL BE ON THE WEAK SIDE AS WELL. FORECASTS HAVE BEEN TWEAKED FOR
CURRENT SKY AND WEATHER TRENDS AND ARE IN GOOD SHAPE FOR NOW.

.PREVIOUS DISCUSSION...
TODAY THROUGH WEDNESDAY...
AFTER A RATHER WET AND COOL MONDAY...WITH SOME OF THE MOST FAVORED
AREAS ACROSS NORTHERN MARICOPA COUNTY SEEING UP TO AN INCH OF
RAIN...TODAY LOOKS LIKE IT WILL BE A QUIETER ONE...AS THE UPPER TROF
THAT BROUGHT US ALL THE RAIN AND CLOUDS HAS NOW MOVED OFF WELL TO
OUR EAST...INTO THE CENTRAL PLAINS.

HOWEVER...THE WEATHER TODAY AND TONIGHT STILL LOOKS LIKE IT WILL BE
RATHER UNSETTLED...WITH ISOLATED-TO-SCATTERED SHOWERS TO CONTINUE
OVER SOUTH-CENTRAL ARIZONA...ESPECIALLY OVER THE HIGHER TERRAIN
NORTH AND EAST OF PHOENIX. THIS CONTINUATION OF SHOWER CHANCES IS
DUE TO A COMBINATION OF MOIST SOUTHWESTERLY FLOW ALOFT THAT IS BEING
GENERATED BY ANOTHER UPPER LOW CENTER THAT IS NOW POSITIONED OFF THE
SOUTHERN CA COAST THIS MORNING...AND A COUPLE OF WEAK SHORTWAVES
THAT WILL BE DROPPING SOUTHWARD ACROSS AZ AS THE STRONG LONG-WAVE
UPPER TROF THEY ARE EMBEDDED IN MOVES SOUTHEASTWARD ACROSS THE
CENTRAL ROCKIES INTO THE CENTRAL PLAINS. ALTHOUGH MOISTURE LEVELS
THROUGH THE COLUMN LOOK TO BE RATHER LIMITED...WITH PWATS IN THE
0.50-0.60 INCH RANGE...THERE APPEARS THAT THERE WILL BE ENOUGH
DYNAMICS/INSTABILITY TO TRIGGER LIGHT SHOWERS...AND EVEN ONE OR TWO
THUNDERSTORMS TODAY AND TONIGHT AS THE SHORTWAVES PASS ACROSS THE
REGION...WITH PERHAPS A TENTH OF AN INCH OR SO OF RAIN FALLING FROM
THE HEAVIER SHOWERS...AND EVEN A DUSTING OF SNOW OVER OUR HIGHEST
PEAKS. TEMPERATURES ARE EXPECTED TO REMAIN BELOW NORMAL TODAY...WITH
850MB TEMPERATURES AROUND 5C KEEPING LOWER DESERT HIGHS DOWN IN THE
60S AND LOW 70S...IN SPITE OF CONSIDERABLE SUNSHINE. THE CHANCES FOR
PRECIP WILL PRETTY MUCH END BY MIDDAY ON WEDNESDAY AS THE UPPER LOW
THAT IS NOW OFF THE SOUTHERN CA COAST MOVES OFF WELL TO OUR SOUTH
AND EAST...CUTTING OFF THE MOISTURE FEED FROM THE PACIFIC...AND
RIDGING BEGINS TO BUILD IN FROM THE WEST BEHIND THE MAIN LONG-WAVE
TROF.

THURSDAY...

A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO EARLY NEXT WEEK...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A GOOD CHANCE FOR HIGHS NEAR 80 ACROSS THE LOWER
DESERTS BY THE WEEKEND...AND EVEN INTO THE MID 80S BY NEXT TUESDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
LOCALIZED AND PATCHY FOG DEVELOPMENT WILL CONTINUE TO FAVOR AREAS OF
THE SOUTHEAST PHX METRO AND NW PINAL COUNTY THROUGH THE MORNING...AT
TIMES GENERATING LOCALLY DENSE VSBYS INTO IFR VALUES. ANOTHER ROUND
OF MID TO HIGH LEVEL CLOUDS WILL APPROACH FROM THE SOUTHWEST...WHICH
SHOULD HELP MITIGATE FURTHER FOG DEVELOPMENT THIS MORNING. CANNOT
RULE OUT ISOLATED SHOWER DEVELOP LATER INTO THE DAY/AFTERNOON WITH
THE UPPER TROUGH AXIS STILL OVERHEAD AND ABUNDANT LOW-LEVEL MOISTURE
STILL PREVALENT. HOWEVER...WILL NOT INCLUDE MENTION IN THE TAFS THIS
TIME UNTIL COVERAGE PICKS UP ON AREA RADARS. SFC WINDS WILL REMAIN
LIGHT THROUGH WEDNESDAY MORNING...AND TYPICAL OVERNIGHT SHIFT TO AN
EASTERLY DIRECTION MAY BE VERY DELAYED OR NON-EXISTENT LATE TONIGHT.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
NO AVIATION CONCERNS THROUGH WEDNESDAY MORNING WITH JUST OCCASIONAL
HIGH CLOUDS AND A FEW AFTERNOON CU TO DEAL WITH. SFC WINDS WILL
GENERALLY FAVOR A NORTHWEST DIRECTION...HOWEVER THE WEAK PRESSURE
GRADIENT MAY ALLOW EXTENDED PERIODS OF VARIABLE DIRECTION WITH
SPEEDS AOB 6 KT.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
STRONG HIGH PRESSURE WILL PROVIDE SEASONABLY WARM AND DRY CONDITIONS
TO THE DISTRICT DURING THE END OF OF THIS WEEK INTO EARLY NEXT WEEK.
WITH TEMPERATURES SLIGHTLY ABOVE NORMAL...AFTERNOON HUMIDITY LEVELS
WILL REGULARLY FALL INTO A 15 TO 25 PERCENT RANGE WITH GOOD
OVERNIGHT RECOVERY. WINDS WILL FAVOR A NORTH TO NORTHEAST TRAJECTORY
THROUGH THE PERIOD...WITH SOME OCCASIONAL GUSTINESS OVER RIDGE TOPS
BUT ALL IN ALL VERY TYPICAL SPEEDS. OVERALL...FIRE DANGER WILL BE
LIMITED DURING THIS TIME FRAME.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...PERCHA/CB
AVIATION...NOLTE/MO
FIRE WEATHER...MO













000
FXUS65 KPSR 031547
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
847 AM MST TUE MAR 3 2015

.UPDATE...TO AVIATION DISCUSSION...


&&

.SYNOPSIS...
LOW PRESSURE...THAT WILL BE MOVING SLOWLY SOUTHWARD ACROSS THE
REGION...WILL KEEP THE WEATHER RATHER UNSETTLED AND COOL THROUGH
WEDNESDAY. A SLIGHT CHANCE OF SHOWERS...AND EVEN A FEW THUNDERSTORMS
CAN BE EXPECTED OVER SOUTH CENTRAL ARIZONA THROUGH TUESDAY EVENING.
A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY THURSDAY...INTO
THE WEEKEND AS HIGH PRESSURE SYSTEM BUILDS OVER THE DESERT
SOUTHWEST.

&&

.DISCUSSION...
TODAY THROUGH WEDNESDAY...

AFTER A RATHER WET AND COOL MONDAY...WITH SOME OF THE MOST FAVORED
AREAS ACROSS NORTHERN MARICOPA COUNTY SEEING UP TO AN INCH OF
RAIN...TODAY LOOKS LIKE IT WILL BE A QUIETER ONE...AS THE UPPER TROF
THAT BROUGHT US ALL THE RAIN AND CLOUDS HAS NOW MOVED OFF WELL TO
OUR EAST...INTO THE CENTRAL PLAINS.

HOWEVER...THE WEATHER TODAY AND TONIGHT STILL LOOKS LIKE IT WILL BE
RATHER UNSETTLED...WITH ISOLATED-TO-SCATTERED SHOWERS TO CONTINUE
OVER SOUTH-CENTRAL ARIZONA...ESPECIALLY OVER THE HIGHER TERRAIN
NORTH AND EAST OF PHOENIX. THIS CONTINUATION OF SHOWER CHANCES IS
DUE TO A COMBINATION OF MOIST SOUTHWESTERLY FLOW ALOFT THAT IS BEING
GENERATED BY ANOTHER UPPER LOW CENTER THAT IS NOW POSITIONED OFF THE
SOUTHERN CA COAST THIS MORNING...AND A COUPLE OF WEAK SHORTWAVES
THAT WILL BE DROPPING SOUTHWARD ACROSS AZ AS THE STRONG LONG-WAVE
UPPER TROF THEY ARE EMBEDDED IN MOVES SOUTHEASTWARD ACROSS THE
CENTRAL ROCKIES INTO THE CENTRAL PLAINS. ALTHOUGH MOISTURE LEVELS
THROUGH THE COLUMN LOOK TO BE RATHER LIMITED...WITH PWATS IN THE
0.50-0.60 INCH RANGE...THERE APPEARS THAT THERE WILL BE ENOUGH
DYNAMICS/INSTABILITY TO TRIGGER LIGHT SHOWERS...AND EVEN ONE OR TWO
THUNDERSTORMS TODAY AND TONIGHT AS THE SHORTWAVES PASS ACROSS THE
REGION...WITH PERHAPS A TENTH OF AN INCH OR SO OF RAIN FALLING FROM
THE HEAVIER SHOWERS...AND EVEN A DUSTING OF SNOW OVER OUR HIGHEST
PEAKS. TEMPERATURES ARE EXPECTED TO REMAIN BELOW NORMAL TODAY...WITH
850MB TEMPERATURES AROUND 5C KEEPING LOWER DESERT HIGHS DOWN IN THE
60S AND LOW 70S...IN SPITE OF CONSIDERABLE SUNSHINE. THE CHANCES FOR
PRECIP WILL PRETTY MUCH END BY MIDDAY ON WEDNESDAY AS THE UPPER LOW
THAT IS NOW OFF THE SOUTHERN CA COAST MOVES OFF WELL TO OUR SOUTH
AND EAST...CUTTING OFF THE MOISTURE FEED FROM THE PACIFIC...AND
RIDGING BEGINS TO BUILD IN FROM THE WEST BEHIND THE MAIN LONG-WAVE
TROF.

THURSDAY...

A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO EARLY NEXT WEEK...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A GOOD CHANCE FOR HIGHS NEAR 80 ACROSS THE LOWER
DESERTS BY THE WEEKEND...AND EVEN INTO THE MID 80S BY NEXT TUESDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
LOCALIZED AND PATCHY FOG DEVELOPMENT WILL CONTINUE TO FAVOR AREAS OF
THE SOUTHEAST PHX METRO AND NW PINAL COUNTY THROUGH THE MORNING...AT
TIMES GENERATING LOCALLY DENSE VSBYS INTO IFR VALUES. ANOTHER ROUND
OF MID TO HIGH LEVEL CLOUDS WILL APPROACH FROM THE SOUTHWEST...WHICH
SHOULD HELP MITIGATE FURTHER FOG DEVELOPMENT THIS MORNING. CANNOT
RULE OUT ISOLATED SHOWER DEVELOP LATER INTO THE DAY/AFTERNOON WITH
THE UPPER TROUGH AXIS STILL OVERHEAD AND ABUNDANT LOW-LEVEL MOISTURE
STILL PREVALENT. HOWEVER...WILL NOT INCLUDE MENTION IN THE TAFS THIS
TIME UNTIL COVERAGE PICKS UP ON AREA RADARS. SFC WINDS WILL REMAIN
LIGHT THROUGH WEDNESDAY MORNING...AND TYPICAL OVERNIGHT SHIFT TO AN
EASTERLY DIRECTION MAY BE VERY DELAYED OR NON-EXISTENT LATE TONIGHT.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
NO AVIATION CONCERNS THROUGH WEDNESDAY MORNING WITH JUST OCCASIONAL
HIGH CLOUDS AND A FEW AFTERNOON CU TO DEAL WITH. SFC WINDS WILL
GENERALLY FAVOR A NORTHWEST DIRECTION...HOWEVER THE WEAK PRESSURE
GRADIENT MAY ALLOW EXTENDED PERIODS OF VARIABLE DIRECTION WITH
SPEEDS AOB 6 KT.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
STRONG HIGH PRESSURE WILL PROVIDE SEASONABLY WARM AND DRY CONDITIONS
TO THE DISTRICT DURING THE END OF OF THIS WEEK INTO EARLY NEXT WEEK.
WITH TEMPERATURES SLIGHTLY ABOVE NORMAL...AFTERNOON HUMIDITY LEVELS
WILL REGULARLY FALL INTO A 15 TO 25 PERCENT RANGE WITH GOOD
OVERNIGHT RECOVERY. WINDS WILL FAVOR A NORTH TO NORTHEAST TRAJECTORY
THROUGH THE PERIOD...WITH SOME OCCASIONAL GUSTINESS OVER RIDGE TOPS
BUT ALL IN ALL VERY TYPICAL SPEEDS. OVERALL...FIRE DANGER WILL BE
LIMITED DURING THIS TIME FRAME.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...PERCHA/CB
AVIATION...NOLTE/MO
FIRE WEATHER...MO











000
FXUS65 KPSR 031547
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
847 AM MST TUE MAR 3 2015

.UPDATE...TO AVIATION DISCUSSION...


&&

.SYNOPSIS...
LOW PRESSURE...THAT WILL BE MOVING SLOWLY SOUTHWARD ACROSS THE
REGION...WILL KEEP THE WEATHER RATHER UNSETTLED AND COOL THROUGH
WEDNESDAY. A SLIGHT CHANCE OF SHOWERS...AND EVEN A FEW THUNDERSTORMS
CAN BE EXPECTED OVER SOUTH CENTRAL ARIZONA THROUGH TUESDAY EVENING.
A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY THURSDAY...INTO
THE WEEKEND AS HIGH PRESSURE SYSTEM BUILDS OVER THE DESERT
SOUTHWEST.

&&

.DISCUSSION...
TODAY THROUGH WEDNESDAY...

AFTER A RATHER WET AND COOL MONDAY...WITH SOME OF THE MOST FAVORED
AREAS ACROSS NORTHERN MARICOPA COUNTY SEEING UP TO AN INCH OF
RAIN...TODAY LOOKS LIKE IT WILL BE A QUIETER ONE...AS THE UPPER TROF
THAT BROUGHT US ALL THE RAIN AND CLOUDS HAS NOW MOVED OFF WELL TO
OUR EAST...INTO THE CENTRAL PLAINS.

HOWEVER...THE WEATHER TODAY AND TONIGHT STILL LOOKS LIKE IT WILL BE
RATHER UNSETTLED...WITH ISOLATED-TO-SCATTERED SHOWERS TO CONTINUE
OVER SOUTH-CENTRAL ARIZONA...ESPECIALLY OVER THE HIGHER TERRAIN
NORTH AND EAST OF PHOENIX. THIS CONTINUATION OF SHOWER CHANCES IS
DUE TO A COMBINATION OF MOIST SOUTHWESTERLY FLOW ALOFT THAT IS BEING
GENERATED BY ANOTHER UPPER LOW CENTER THAT IS NOW POSITIONED OFF THE
SOUTHERN CA COAST THIS MORNING...AND A COUPLE OF WEAK SHORTWAVES
THAT WILL BE DROPPING SOUTHWARD ACROSS AZ AS THE STRONG LONG-WAVE
UPPER TROF THEY ARE EMBEDDED IN MOVES SOUTHEASTWARD ACROSS THE
CENTRAL ROCKIES INTO THE CENTRAL PLAINS. ALTHOUGH MOISTURE LEVELS
THROUGH THE COLUMN LOOK TO BE RATHER LIMITED...WITH PWATS IN THE
0.50-0.60 INCH RANGE...THERE APPEARS THAT THERE WILL BE ENOUGH
DYNAMICS/INSTABILITY TO TRIGGER LIGHT SHOWERS...AND EVEN ONE OR TWO
THUNDERSTORMS TODAY AND TONIGHT AS THE SHORTWAVES PASS ACROSS THE
REGION...WITH PERHAPS A TENTH OF AN INCH OR SO OF RAIN FALLING FROM
THE HEAVIER SHOWERS...AND EVEN A DUSTING OF SNOW OVER OUR HIGHEST
PEAKS. TEMPERATURES ARE EXPECTED TO REMAIN BELOW NORMAL TODAY...WITH
850MB TEMPERATURES AROUND 5C KEEPING LOWER DESERT HIGHS DOWN IN THE
60S AND LOW 70S...IN SPITE OF CONSIDERABLE SUNSHINE. THE CHANCES FOR
PRECIP WILL PRETTY MUCH END BY MIDDAY ON WEDNESDAY AS THE UPPER LOW
THAT IS NOW OFF THE SOUTHERN CA COAST MOVES OFF WELL TO OUR SOUTH
AND EAST...CUTTING OFF THE MOISTURE FEED FROM THE PACIFIC...AND
RIDGING BEGINS TO BUILD IN FROM THE WEST BEHIND THE MAIN LONG-WAVE
TROF.

THURSDAY...

A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO EARLY NEXT WEEK...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A GOOD CHANCE FOR HIGHS NEAR 80 ACROSS THE LOWER
DESERTS BY THE WEEKEND...AND EVEN INTO THE MID 80S BY NEXT TUESDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
LOCALIZED AND PATCHY FOG DEVELOPMENT WILL CONTINUE TO FAVOR AREAS OF
THE SOUTHEAST PHX METRO AND NW PINAL COUNTY THROUGH THE MORNING...AT
TIMES GENERATING LOCALLY DENSE VSBYS INTO IFR VALUES. ANOTHER ROUND
OF MID TO HIGH LEVEL CLOUDS WILL APPROACH FROM THE SOUTHWEST...WHICH
SHOULD HELP MITIGATE FURTHER FOG DEVELOPMENT THIS MORNING. CANNOT
RULE OUT ISOLATED SHOWER DEVELOP LATER INTO THE DAY/AFTERNOON WITH
THE UPPER TROUGH AXIS STILL OVERHEAD AND ABUNDANT LOW-LEVEL MOISTURE
STILL PREVALENT. HOWEVER...WILL NOT INCLUDE MENTION IN THE TAFS THIS
TIME UNTIL COVERAGE PICKS UP ON AREA RADARS. SFC WINDS WILL REMAIN
LIGHT THROUGH WEDNESDAY MORNING...AND TYPICAL OVERNIGHT SHIFT TO AN
EASTERLY DIRECTION MAY BE VERY DELAYED OR NON-EXISTENT LATE TONIGHT.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
NO AVIATION CONCERNS THROUGH WEDNESDAY MORNING WITH JUST OCCASIONAL
HIGH CLOUDS AND A FEW AFTERNOON CU TO DEAL WITH. SFC WINDS WILL
GENERALLY FAVOR A NORTHWEST DIRECTION...HOWEVER THE WEAK PRESSURE
GRADIENT MAY ALLOW EXTENDED PERIODS OF VARIABLE DIRECTION WITH
SPEEDS AOB 6 KT.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
STRONG HIGH PRESSURE WILL PROVIDE SEASONABLY WARM AND DRY CONDITIONS
TO THE DISTRICT DURING THE END OF OF THIS WEEK INTO EARLY NEXT WEEK.
WITH TEMPERATURES SLIGHTLY ABOVE NORMAL...AFTERNOON HUMIDITY LEVELS
WILL REGULARLY FALL INTO A 15 TO 25 PERCENT RANGE WITH GOOD
OVERNIGHT RECOVERY. WINDS WILL FAVOR A NORTH TO NORTHEAST TRAJECTORY
THROUGH THE PERIOD...WITH SOME OCCASIONAL GUSTINESS OVER RIDGE TOPS
BUT ALL IN ALL VERY TYPICAL SPEEDS. OVERALL...FIRE DANGER WILL BE
LIMITED DURING THIS TIME FRAME.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...PERCHA/CB
AVIATION...NOLTE/MO
FIRE WEATHER...MO










000
FXUS65 KPSR 031207
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
505 AM MST TUE MAR 3 2015

...UPDATED AVIATION AND FIRE WEATHER...

.SYNOPSIS...
LOW PRESSURE...THAT WILL BE MOVING SLOWLY SOUTHWARD ACROSS THE
REGION...WILL KEEP THE WEATHER RATHER UNSETTLED AND COOL THROUGH
WEDNESDAY. A SLIGHT CHANCE OF SHOWERS...AND EVEN A FEW THUNDERSTORMS
CAN BE EXPECTED OVER SOUTH CENTRAL ARIZONA THROUGH TUESDAY EVENING.
A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY THURSDAY...INTO
THE WEEKEND AS HIGH PRESSURE SYSTEM BUILDS OVER THE DESERT
SOUTHWEST.

&&

.DISCUSSION...
TODAY THROUGH WEDNESDAY...

AFTER A RATHER WET AND COOL MONDAY...WITH SOME OF THE MOST FAVORED
AREAS ACROSS NORTHERN MARICOPA COUNTY SEEING UP TO AN INCH OF
RAIN...TODAY LOOKS LIKE IT WILL BE A QUIETER ONE...AS THE UPPER TROF
THAT BROUGHT US ALL THE RAIN AND CLOUDS HAS NOW MOVED OFF WELL TO
OUR EAST...INTO THE CENTRAL PLAINS.

HOWEVER...THE WEATHER TODAY AND TONIGHT STILL LOOKS LIKE IT WILL BE
RATHER UNSETTLED...WITH ISOLATED-TO-SCATTERED SHOWERS TO CONTINUE
OVER SOUTH-CENTRAL ARIZONA...ESPECIALLY OVER THE HIGHER TERRAIN
NORTH AND EAST OF PHOENIX. THIS CONTINUATION OF SHOWER CHANCES IS
DUE TO A COMBINATION OF MOIST SOUTHWESTERLY FLOW ALOFT THAT IS BEING
GENERATED BY ANOTHER UPPER LOW CENTER THAT IS NOW POSITIONED OFF THE
SOUTHERN CA COAST THIS MORNING...AND A COUPLE OF WEAK SHORTWAVES
THAT WILL BE DROPPING SOUTHWARD ACROSS AZ AS THE STRONG LONG-WAVE
UPPER TROF THEY ARE EMBEDDED IN MOVES SOUTHEASTWARD ACROSS THE
CENTRAL ROCKIES INTO THE CENTRAL PLAINS. ALTHOUGH MOISTURE LEVELS
THROUGH THE COLUMN LOOK TO BE RATHER LIMITED...WITH PWATS IN THE
0.50-0.60 INCH RANGE...THERE APPEARS THAT THERE WILL BE ENOUGH
DYNAMICS/INSTABILITY TO TRIGGER LIGHT SHOWERS...AND EVEN ONE OR TWO
THUNDERSTORMS TODAY AND TONIGHT AS THE SHORTWAVES PASS ACROSS THE
REGION...WITH PERHAPS A TENTH OF AN INCH OR SO OF RAIN FALLING FROM
THE HEAVIER SHOWERS...AND EVEN A DUSTING OF SNOW OVER OUR HIGHEST
PEAKS. TEMPERATURES ARE EXPECTED TO REMAIN BELOW NORMAL TODAY...WITH
850MB TEMPERATURES AROUND 5C KEEPING LOWER DESERT HIGHS DOWN IN THE
60S AND LOW 70S...IN SPITE OF CONSIDERABLE SUNSHINE. THE CHANCES FOR
PRECIP WILL PRETTY MUCH END BY MIDDAY ON WEDNESDAY AS THE UPPER LOW
THAT IS NOW OFF THE SOUTHERN CA COAST MOVES OFF WELL TO OUR SOUTH
AND EAST...CUTTING OFF THE MOISTURE FEED FROM THE PACIFIC...AND
RIDGING BEGINS TO BUILD IN FROM THE WEST BEHIND THE MAIN LONG-WAVE
TROF.

THURSDAY...

A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO EARLY NEXT WEEK...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A GOOD CHANCE FOR HIGHS NEAR 80 ACROSS THE LOWER
DESERTS BY THE WEEKEND...AND EVEN INTO THE MID 80S BY NEXT TUESDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
AREAS OF SCT-BKN 4K-6K FT STRATO-CU HAVE BEEN SLOW TO CLEAR OVER
CNTRL ARIZONA THIS MORNING. MORE FEW-SCT CONDITIONS WILL LIKELY
PREVAIL MID MORNING...HOWEVER DAYTIME HEATING MAY ALLOW FOR BKN
REDEVELOPMENT DURING THE AFTERNOON...ALBEIT WITH BASE HEIGHTS ABOVE
6K FT. WHILE SOME MVFR HZ/BR MAY AFFECT KIWA BEFORE 15Z (MORE
REMOVED FROM THE CITY)...ANY MORE EXTENSIVE FOG WILL STAY WELL SOUTH
OF TERMINAL LOCATIONS. SFC WINDS WILL REMAIN LIGHT THROUGH WEDNESDAY
MORNING...AND TYPICAL OVERNIGHT SHIFT TO AN EASTERLY DIRECTION MAY
BE VERY DELAYED OR NON-EXISTENT LATE TONIGHT.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
NO AVIATION CONCERNS THROUGH WEDNESDAY MORNING WITH JUST OCCASIONAL
HIGH CLOUDS AND A FEW AFTERNOON CU TO DEAL WITH. SFC WINDS WILL
GENERALLY FAVOR A NORTHWEST DIRECTION...HOWEVER THE WEAK PRESSURE
GRADIENT MAY ALLOW EXTENDED PERIODS OF VARIABLE DIRECTION WITH
SPEEDS AOB 6 KT.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
STRONG HIGH PRESSURE WILL PROVIDE SEASONABLY WARM AND DRY CONDITIONS
TO THE DISTRICT DURING THE END OF OF THIS WEEK INTO EARLY NEXT WEEK.
WITH TEMPERATURES SLIGHTLY ABOVE NORMAL...AFTERNOON HUMIDITY LEVELS
WILL REGULARLY FALL INTO A 15 TO 25 PERCENT RANGE WITH GOOD
OVERNIGHT RECOVERY. WINDS WILL FAVOR A NORTH TO NORTHEAST TRAJECTORY
THROUGH THE PERIOD...WITH SOME OCCASIONAL GUSTINESS OVER RIDGE TOPS
BUT ALL IN ALL VERY TYPICAL SPEEDS. OVERALL...FIRE DANGER WILL BE
LIMITED DURING THIS TIME FRAME.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...PERCHA/CB
AVIATION...MO
FIRE WEATHER...MO








000
FXUS65 KPSR 031207
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
505 AM MST TUE MAR 3 2015

...UPDATED AVIATION AND FIRE WEATHER...

.SYNOPSIS...
LOW PRESSURE...THAT WILL BE MOVING SLOWLY SOUTHWARD ACROSS THE
REGION...WILL KEEP THE WEATHER RATHER UNSETTLED AND COOL THROUGH
WEDNESDAY. A SLIGHT CHANCE OF SHOWERS...AND EVEN A FEW THUNDERSTORMS
CAN BE EXPECTED OVER SOUTH CENTRAL ARIZONA THROUGH TUESDAY EVENING.
A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY THURSDAY...INTO
THE WEEKEND AS HIGH PRESSURE SYSTEM BUILDS OVER THE DESERT
SOUTHWEST.

&&

.DISCUSSION...
TODAY THROUGH WEDNESDAY...

AFTER A RATHER WET AND COOL MONDAY...WITH SOME OF THE MOST FAVORED
AREAS ACROSS NORTHERN MARICOPA COUNTY SEEING UP TO AN INCH OF
RAIN...TODAY LOOKS LIKE IT WILL BE A QUIETER ONE...AS THE UPPER TROF
THAT BROUGHT US ALL THE RAIN AND CLOUDS HAS NOW MOVED OFF WELL TO
OUR EAST...INTO THE CENTRAL PLAINS.

HOWEVER...THE WEATHER TODAY AND TONIGHT STILL LOOKS LIKE IT WILL BE
RATHER UNSETTLED...WITH ISOLATED-TO-SCATTERED SHOWERS TO CONTINUE
OVER SOUTH-CENTRAL ARIZONA...ESPECIALLY OVER THE HIGHER TERRAIN
NORTH AND EAST OF PHOENIX. THIS CONTINUATION OF SHOWER CHANCES IS
DUE TO A COMBINATION OF MOIST SOUTHWESTERLY FLOW ALOFT THAT IS BEING
GENERATED BY ANOTHER UPPER LOW CENTER THAT IS NOW POSITIONED OFF THE
SOUTHERN CA COAST THIS MORNING...AND A COUPLE OF WEAK SHORTWAVES
THAT WILL BE DROPPING SOUTHWARD ACROSS AZ AS THE STRONG LONG-WAVE
UPPER TROF THEY ARE EMBEDDED IN MOVES SOUTHEASTWARD ACROSS THE
CENTRAL ROCKIES INTO THE CENTRAL PLAINS. ALTHOUGH MOISTURE LEVELS
THROUGH THE COLUMN LOOK TO BE RATHER LIMITED...WITH PWATS IN THE
0.50-0.60 INCH RANGE...THERE APPEARS THAT THERE WILL BE ENOUGH
DYNAMICS/INSTABILITY TO TRIGGER LIGHT SHOWERS...AND EVEN ONE OR TWO
THUNDERSTORMS TODAY AND TONIGHT AS THE SHORTWAVES PASS ACROSS THE
REGION...WITH PERHAPS A TENTH OF AN INCH OR SO OF RAIN FALLING FROM
THE HEAVIER SHOWERS...AND EVEN A DUSTING OF SNOW OVER OUR HIGHEST
PEAKS. TEMPERATURES ARE EXPECTED TO REMAIN BELOW NORMAL TODAY...WITH
850MB TEMPERATURES AROUND 5C KEEPING LOWER DESERT HIGHS DOWN IN THE
60S AND LOW 70S...IN SPITE OF CONSIDERABLE SUNSHINE. THE CHANCES FOR
PRECIP WILL PRETTY MUCH END BY MIDDAY ON WEDNESDAY AS THE UPPER LOW
THAT IS NOW OFF THE SOUTHERN CA COAST MOVES OFF WELL TO OUR SOUTH
AND EAST...CUTTING OFF THE MOISTURE FEED FROM THE PACIFIC...AND
RIDGING BEGINS TO BUILD IN FROM THE WEST BEHIND THE MAIN LONG-WAVE
TROF.

THURSDAY...

A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO EARLY NEXT WEEK...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A GOOD CHANCE FOR HIGHS NEAR 80 ACROSS THE LOWER
DESERTS BY THE WEEKEND...AND EVEN INTO THE MID 80S BY NEXT TUESDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
AREAS OF SCT-BKN 4K-6K FT STRATO-CU HAVE BEEN SLOW TO CLEAR OVER
CNTRL ARIZONA THIS MORNING. MORE FEW-SCT CONDITIONS WILL LIKELY
PREVAIL MID MORNING...HOWEVER DAYTIME HEATING MAY ALLOW FOR BKN
REDEVELOPMENT DURING THE AFTERNOON...ALBEIT WITH BASE HEIGHTS ABOVE
6K FT. WHILE SOME MVFR HZ/BR MAY AFFECT KIWA BEFORE 15Z (MORE
REMOVED FROM THE CITY)...ANY MORE EXTENSIVE FOG WILL STAY WELL SOUTH
OF TERMINAL LOCATIONS. SFC WINDS WILL REMAIN LIGHT THROUGH WEDNESDAY
MORNING...AND TYPICAL OVERNIGHT SHIFT TO AN EASTERLY DIRECTION MAY
BE VERY DELAYED OR NON-EXISTENT LATE TONIGHT.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
NO AVIATION CONCERNS THROUGH WEDNESDAY MORNING WITH JUST OCCASIONAL
HIGH CLOUDS AND A FEW AFTERNOON CU TO DEAL WITH. SFC WINDS WILL
GENERALLY FAVOR A NORTHWEST DIRECTION...HOWEVER THE WEAK PRESSURE
GRADIENT MAY ALLOW EXTENDED PERIODS OF VARIABLE DIRECTION WITH
SPEEDS AOB 6 KT.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
STRONG HIGH PRESSURE WILL PROVIDE SEASONABLY WARM AND DRY CONDITIONS
TO THE DISTRICT DURING THE END OF OF THIS WEEK INTO EARLY NEXT WEEK.
WITH TEMPERATURES SLIGHTLY ABOVE NORMAL...AFTERNOON HUMIDITY LEVELS
WILL REGULARLY FALL INTO A 15 TO 25 PERCENT RANGE WITH GOOD
OVERNIGHT RECOVERY. WINDS WILL FAVOR A NORTH TO NORTHEAST TRAJECTORY
THROUGH THE PERIOD...WITH SOME OCCASIONAL GUSTINESS OVER RIDGE TOPS
BUT ALL IN ALL VERY TYPICAL SPEEDS. OVERALL...FIRE DANGER WILL BE
LIMITED DURING THIS TIME FRAME.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...PERCHA/CB
AVIATION...MO
FIRE WEATHER...MO







000
FXUS65 KPSR 031207
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
505 AM MST TUE MAR 3 2015

...UPDATED AVIATION AND FIRE WEATHER...

.SYNOPSIS...
LOW PRESSURE...THAT WILL BE MOVING SLOWLY SOUTHWARD ACROSS THE
REGION...WILL KEEP THE WEATHER RATHER UNSETTLED AND COOL THROUGH
WEDNESDAY. A SLIGHT CHANCE OF SHOWERS...AND EVEN A FEW THUNDERSTORMS
CAN BE EXPECTED OVER SOUTH CENTRAL ARIZONA THROUGH TUESDAY EVENING.
A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY THURSDAY...INTO
THE WEEKEND AS HIGH PRESSURE SYSTEM BUILDS OVER THE DESERT
SOUTHWEST.

&&

.DISCUSSION...
TODAY THROUGH WEDNESDAY...

AFTER A RATHER WET AND COOL MONDAY...WITH SOME OF THE MOST FAVORED
AREAS ACROSS NORTHERN MARICOPA COUNTY SEEING UP TO AN INCH OF
RAIN...TODAY LOOKS LIKE IT WILL BE A QUIETER ONE...AS THE UPPER TROF
THAT BROUGHT US ALL THE RAIN AND CLOUDS HAS NOW MOVED OFF WELL TO
OUR EAST...INTO THE CENTRAL PLAINS.

HOWEVER...THE WEATHER TODAY AND TONIGHT STILL LOOKS LIKE IT WILL BE
RATHER UNSETTLED...WITH ISOLATED-TO-SCATTERED SHOWERS TO CONTINUE
OVER SOUTH-CENTRAL ARIZONA...ESPECIALLY OVER THE HIGHER TERRAIN
NORTH AND EAST OF PHOENIX. THIS CONTINUATION OF SHOWER CHANCES IS
DUE TO A COMBINATION OF MOIST SOUTHWESTERLY FLOW ALOFT THAT IS BEING
GENERATED BY ANOTHER UPPER LOW CENTER THAT IS NOW POSITIONED OFF THE
SOUTHERN CA COAST THIS MORNING...AND A COUPLE OF WEAK SHORTWAVES
THAT WILL BE DROPPING SOUTHWARD ACROSS AZ AS THE STRONG LONG-WAVE
UPPER TROF THEY ARE EMBEDDED IN MOVES SOUTHEASTWARD ACROSS THE
CENTRAL ROCKIES INTO THE CENTRAL PLAINS. ALTHOUGH MOISTURE LEVELS
THROUGH THE COLUMN LOOK TO BE RATHER LIMITED...WITH PWATS IN THE
0.50-0.60 INCH RANGE...THERE APPEARS THAT THERE WILL BE ENOUGH
DYNAMICS/INSTABILITY TO TRIGGER LIGHT SHOWERS...AND EVEN ONE OR TWO
THUNDERSTORMS TODAY AND TONIGHT AS THE SHORTWAVES PASS ACROSS THE
REGION...WITH PERHAPS A TENTH OF AN INCH OR SO OF RAIN FALLING FROM
THE HEAVIER SHOWERS...AND EVEN A DUSTING OF SNOW OVER OUR HIGHEST
PEAKS. TEMPERATURES ARE EXPECTED TO REMAIN BELOW NORMAL TODAY...WITH
850MB TEMPERATURES AROUND 5C KEEPING LOWER DESERT HIGHS DOWN IN THE
60S AND LOW 70S...IN SPITE OF CONSIDERABLE SUNSHINE. THE CHANCES FOR
PRECIP WILL PRETTY MUCH END BY MIDDAY ON WEDNESDAY AS THE UPPER LOW
THAT IS NOW OFF THE SOUTHERN CA COAST MOVES OFF WELL TO OUR SOUTH
AND EAST...CUTTING OFF THE MOISTURE FEED FROM THE PACIFIC...AND
RIDGING BEGINS TO BUILD IN FROM THE WEST BEHIND THE MAIN LONG-WAVE
TROF.

THURSDAY...

A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO EARLY NEXT WEEK...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A GOOD CHANCE FOR HIGHS NEAR 80 ACROSS THE LOWER
DESERTS BY THE WEEKEND...AND EVEN INTO THE MID 80S BY NEXT TUESDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
AREAS OF SCT-BKN 4K-6K FT STRATO-CU HAVE BEEN SLOW TO CLEAR OVER
CNTRL ARIZONA THIS MORNING. MORE FEW-SCT CONDITIONS WILL LIKELY
PREVAIL MID MORNING...HOWEVER DAYTIME HEATING MAY ALLOW FOR BKN
REDEVELOPMENT DURING THE AFTERNOON...ALBEIT WITH BASE HEIGHTS ABOVE
6K FT. WHILE SOME MVFR HZ/BR MAY AFFECT KIWA BEFORE 15Z (MORE
REMOVED FROM THE CITY)...ANY MORE EXTENSIVE FOG WILL STAY WELL SOUTH
OF TERMINAL LOCATIONS. SFC WINDS WILL REMAIN LIGHT THROUGH WEDNESDAY
MORNING...AND TYPICAL OVERNIGHT SHIFT TO AN EASTERLY DIRECTION MAY
BE VERY DELAYED OR NON-EXISTENT LATE TONIGHT.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
NO AVIATION CONCERNS THROUGH WEDNESDAY MORNING WITH JUST OCCASIONAL
HIGH CLOUDS AND A FEW AFTERNOON CU TO DEAL WITH. SFC WINDS WILL
GENERALLY FAVOR A NORTHWEST DIRECTION...HOWEVER THE WEAK PRESSURE
GRADIENT MAY ALLOW EXTENDED PERIODS OF VARIABLE DIRECTION WITH
SPEEDS AOB 6 KT.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
STRONG HIGH PRESSURE WILL PROVIDE SEASONABLY WARM AND DRY CONDITIONS
TO THE DISTRICT DURING THE END OF OF THIS WEEK INTO EARLY NEXT WEEK.
WITH TEMPERATURES SLIGHTLY ABOVE NORMAL...AFTERNOON HUMIDITY LEVELS
WILL REGULARLY FALL INTO A 15 TO 25 PERCENT RANGE WITH GOOD
OVERNIGHT RECOVERY. WINDS WILL FAVOR A NORTH TO NORTHEAST TRAJECTORY
THROUGH THE PERIOD...WITH SOME OCCASIONAL GUSTINESS OVER RIDGE TOPS
BUT ALL IN ALL VERY TYPICAL SPEEDS. OVERALL...FIRE DANGER WILL BE
LIMITED DURING THIS TIME FRAME.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...PERCHA/CB
AVIATION...MO
FIRE WEATHER...MO








000
FXUS65 KPSR 030917
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
220 AM MST TUE MAR 3 2015

.SYNOPSIS...
LOW PRESSURE...THAT WILL BE MOVING SLOWLY SOUTHWARD ACROSS THE
REGION...WILL KEEP THE WEATHER RATHER UNSETTLED AND COOL THROUGH
WEDNESDAY. A SLIGHT CHANCE OF SHOWERS...AND EVEN A FEW THUNDERSTORMS
CAN BE EXPECTED OVER SOUTH CENTRAL ARIZONA THROUGH TUESDAY EVENING.
A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY THURSDAY...INTO
THE WEEKEND AS HIGH PRESSURE SYSTEM BUILDS OVER THE DESERT
SOUTHWEST.

&&

.DISCUSSION...
TODAY THROUGH WEDNESDAY...

AFTER A RATHER WET AND COOL MONDAY...WITH SOME OF THE MOST FAVORED
AREAS ACROSS NORTHERN MARICOPA COUNTY SEEING UP TO AN INCH OF
RAIN...TODAY LOOKS LIKE IT WILL BE A QUIETER ONE...AS THE UPPER TROF
THAT BROUGHT US ALL THE RAIN AND CLOUDS HAS NOW MOVED OFF WELL TO
OUR EAST...INTO THE CENTRAL PLAINS.

HOWEVER...THE WEATHER TODAY AND TONIGHT STILL LOOKS LIKE IT WILL BE
RATHER UNSETTLED...WITH ISOLATED-TO-SCATTERED SHOWERS TO CONTINUE
OVER SOUTH-CENTRAL ARIZONA...ESPECIALLY OVER THE HIGHER TERRAIN
NORTH AND EAST OF PHOENIX. THIS CONTINUATION OF SHOWER CHANCES IS
DUE TO A COMBINATION OF MOIST SOUTHWESTERLY FLOW ALOFT THAT IS BEING
GENERATED BY ANOTHER UPPER LOW CENTER THAT IS NOW POSITIONED OFF THE
SOUTHERN CA COAST THIS MORNING...AND A COUPLE OF WEAK SHORTWAVES
THAT WILL BE DROPPING SOUTHWARD ACROSS AZ AS THE STRONG LONG-WAVE
UPPER TROF THEY ARE EMBEDDED IN MOVES SOUTHEASTWARD ACROSS THE
CENTRAL ROCKIES INTO THE CENTRAL PLAINS. ALTHOUGH MOISTURE LEVELS
THROUGH THE COLUMN LOOK TO BE RATHER LIMITED...WITH PWATS IN THE
0.50-0.60 INCH RANGE...THERE APPEARS THAT THERE WILL BE ENOUGH
DYNAMICS/INSTABILITY TO TRIGGER LIGHT SHOWERS...AND EVEN ONE OR TWO
THUNDERSTORMS TODAY AND TONIGHT AS THE SHORTWAVES PASS ACROSS THE
REGION...WITH PERHAPS A TENTH OF AN INCH OR SO OF RAIN FALLING FROM
THE HEAVIER SHOWERS...AND EVEN A DUSTING OF SNOW OVER OUR HIGHEST
PEAKS. TEMPERATURES ARE EXPECTED TO REMAIN BELOW NORMAL TODAY...WITH
850MB TEMPERATURES AROUND 5C KEEPING LOWER DESERT HIGHS DOWN IN THE
60S AND LOW 70S...IN SPITE OF CONSIDERABLE SUNSHINE. THE CHANCES FOR
PRECIP WILL PRETTY MUCH END BY MIDDAY ON WEDNESDAY AS THE UPPER LOW
THAT IS NOW OFF THE SOUTHERN CA COAST MOVES OFF WELL TO OUR SOUTH
AND EAST...CUTTING OFF THE MOISTURE FEED FROM THE PACIFIC...AND
RIDGING BEGINS TO BUILD IN FROM THE WEST BEHIND THE MAIN LONG-WAVE
TROF.

THURSDAY...

A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO EARLY NEXT WEEK...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A GOOD CHANCE FOR HIGHS NEAR 80 ACROSS THE LOWER
DESERTS BY THE WEEKEND...AND EVEN INTO THE MID 80S BY NEXT TUESDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
A BROAD COOL LOW PRESSURE SYSTEM WILL REMAIN OVER THE AREA THROUGH
TUESDAY. VARIABLE AMOUNTS OF MOISTURE WILL CONTINUE A SLIGHT THREAT
OF SHOWERS THROUGH TUESDAY EVENING...ALONG WITH SCT-BKN CLOUDS BASED
BETWEEN 6-8 THSD AGL THROUGH 20Z TUE. LIGHT WIND.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
A BROAD COOL LOW PRESSURE SYSTEM WILL REMAIN OVER THE AREA THROUGH
TUESDAY. VARIABLE AMOUNTS OF MOISTURE WILL CONTINUE SCT-BKN CLOUDS
BASED 8-12 THSD AGL THROUGH 20Z TUE. LIGHT WIND.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
STRONG HIGH PRESSURE AND MUCH DRIER CONDITIONS WILL MOVE BACK INTO
THE DISTRICT DURING THE LATTER HALF OF THE WEEK. TEMPERATURES WILL
REBOUND BACK INTO A NORMAL TO SLIGHTLY ABOVE NORMAL RANGE...WHILE
AFTERNOON HUMIDITY LEVELS RETURN INTO A 15 TO 25 PERCENT RANGE.
OVERNIGHT RECOVERY WILL BE GOOD. PERIODS OF GUSTY NORTH WINDS DOWN
THE COLORADO RIVER VALLEY WILL BE LIKELY WEDNESDAY AFTERNOON...WHILE
OCCASIONAL PERIODS OF STRONGER EASTERLY WINDS OVER RIDGE TOPS OF
CENTRAL ARIZONA MAY BE COMMON LATE IN THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH THROUGH 8 PM TODAY AZZ022>024.

CA...NONE.

&&

$$

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

DISCUSSION...PERCHA/CB
AVIATION...VASQUEZ
FIRE WEATHER...MO






000
FXUS65 KPSR 030917
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
220 AM MST TUE MAR 3 2015

.SYNOPSIS...
LOW PRESSURE...THAT WILL BE MOVING SLOWLY SOUTHWARD ACROSS THE
REGION...WILL KEEP THE WEATHER RATHER UNSETTLED AND COOL THROUGH
WEDNESDAY. A SLIGHT CHANCE OF SHOWERS...AND EVEN A FEW THUNDERSTORMS
CAN BE EXPECTED OVER SOUTH CENTRAL ARIZONA THROUGH TUESDAY EVENING.
A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY THURSDAY...INTO
THE WEEKEND AS HIGH PRESSURE SYSTEM BUILDS OVER THE DESERT
SOUTHWEST.

&&

.DISCUSSION...
TODAY THROUGH WEDNESDAY...

AFTER A RATHER WET AND COOL MONDAY...WITH SOME OF THE MOST FAVORED
AREAS ACROSS NORTHERN MARICOPA COUNTY SEEING UP TO AN INCH OF
RAIN...TODAY LOOKS LIKE IT WILL BE A QUIETER ONE...AS THE UPPER TROF
THAT BROUGHT US ALL THE RAIN AND CLOUDS HAS NOW MOVED OFF WELL TO
OUR EAST...INTO THE CENTRAL PLAINS.

HOWEVER...THE WEATHER TODAY AND TONIGHT STILL LOOKS LIKE IT WILL BE
RATHER UNSETTLED...WITH ISOLATED-TO-SCATTERED SHOWERS TO CONTINUE
OVER SOUTH-CENTRAL ARIZONA...ESPECIALLY OVER THE HIGHER TERRAIN
NORTH AND EAST OF PHOENIX. THIS CONTINUATION OF SHOWER CHANCES IS
DUE TO A COMBINATION OF MOIST SOUTHWESTERLY FLOW ALOFT THAT IS BEING
GENERATED BY ANOTHER UPPER LOW CENTER THAT IS NOW POSITIONED OFF THE
SOUTHERN CA COAST THIS MORNING...AND A COUPLE OF WEAK SHORTWAVES
THAT WILL BE DROPPING SOUTHWARD ACROSS AZ AS THE STRONG LONG-WAVE
UPPER TROF THEY ARE EMBEDDED IN MOVES SOUTHEASTWARD ACROSS THE
CENTRAL ROCKIES INTO THE CENTRAL PLAINS. ALTHOUGH MOISTURE LEVELS
THROUGH THE COLUMN LOOK TO BE RATHER LIMITED...WITH PWATS IN THE
0.50-0.60 INCH RANGE...THERE APPEARS THAT THERE WILL BE ENOUGH
DYNAMICS/INSTABILITY TO TRIGGER LIGHT SHOWERS...AND EVEN ONE OR TWO
THUNDERSTORMS TODAY AND TONIGHT AS THE SHORTWAVES PASS ACROSS THE
REGION...WITH PERHAPS A TENTH OF AN INCH OR SO OF RAIN FALLING FROM
THE HEAVIER SHOWERS...AND EVEN A DUSTING OF SNOW OVER OUR HIGHEST
PEAKS. TEMPERATURES ARE EXPECTED TO REMAIN BELOW NORMAL TODAY...WITH
850MB TEMPERATURES AROUND 5C KEEPING LOWER DESERT HIGHS DOWN IN THE
60S AND LOW 70S...IN SPITE OF CONSIDERABLE SUNSHINE. THE CHANCES FOR
PRECIP WILL PRETTY MUCH END BY MIDDAY ON WEDNESDAY AS THE UPPER LOW
THAT IS NOW OFF THE SOUTHERN CA COAST MOVES OFF WELL TO OUR SOUTH
AND EAST...CUTTING OFF THE MOISTURE FEED FROM THE PACIFIC...AND
RIDGING BEGINS TO BUILD IN FROM THE WEST BEHIND THE MAIN LONG-WAVE
TROF.

THURSDAY...

A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO EARLY NEXT WEEK...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A GOOD CHANCE FOR HIGHS NEAR 80 ACROSS THE LOWER
DESERTS BY THE WEEKEND...AND EVEN INTO THE MID 80S BY NEXT TUESDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
A BROAD COOL LOW PRESSURE SYSTEM WILL REMAIN OVER THE AREA THROUGH
TUESDAY. VARIABLE AMOUNTS OF MOISTURE WILL CONTINUE A SLIGHT THREAT
OF SHOWERS THROUGH TUESDAY EVENING...ALONG WITH SCT-BKN CLOUDS BASED
BETWEEN 6-8 THSD AGL THROUGH 20Z TUE. LIGHT WIND.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
A BROAD COOL LOW PRESSURE SYSTEM WILL REMAIN OVER THE AREA THROUGH
TUESDAY. VARIABLE AMOUNTS OF MOISTURE WILL CONTINUE SCT-BKN CLOUDS
BASED 8-12 THSD AGL THROUGH 20Z TUE. LIGHT WIND.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
STRONG HIGH PRESSURE AND MUCH DRIER CONDITIONS WILL MOVE BACK INTO
THE DISTRICT DURING THE LATTER HALF OF THE WEEK. TEMPERATURES WILL
REBOUND BACK INTO A NORMAL TO SLIGHTLY ABOVE NORMAL RANGE...WHILE
AFTERNOON HUMIDITY LEVELS RETURN INTO A 15 TO 25 PERCENT RANGE.
OVERNIGHT RECOVERY WILL BE GOOD. PERIODS OF GUSTY NORTH WINDS DOWN
THE COLORADO RIVER VALLEY WILL BE LIKELY WEDNESDAY AFTERNOON...WHILE
OCCASIONAL PERIODS OF STRONGER EASTERLY WINDS OVER RIDGE TOPS OF
CENTRAL ARIZONA MAY BE COMMON LATE IN THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH THROUGH 8 PM TODAY AZZ022>024.

CA...NONE.

&&

$$

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

DISCUSSION...PERCHA/CB
AVIATION...VASQUEZ
FIRE WEATHER...MO







000
FXUS65 KPSR 030312
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
810 PM MST MON MAR 2 2015

.SYNOPSIS...
A RELATIVELY COOL LOW PRESSURE SYSTEM WILL LINGER OVER THE REGION
THROUGH WEDNESDAY...PRODUCING PARTLY CLOUDY SKIES AND BELOW NORMAL
TEMPERATURES. A SLIGHT CHANCE OF SHOWERS ARE ALSO FORECAST ACROSS
SOUTHWEST AND SOUTH CENTRAL ARIZONA THROUGH TUESDAY EVENING.
A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY THURSDAY...INTO
THE WEEKEND AS HIGH PRESSURE SYSTEM BUILDS OVER THE DESERT
SOUTHWEST.

&&

.DISCUSSION...
AT 8 PM MST THE COLD FRONT HAD SHIFTED INTO EASTERN ARIZONA ALONG
WITH THE PRECIP BAND. IN THE WAKE OF THE COLD FRONT THIS EVENING A
FEW SHOWERS CONTINUED OVER PORTIONS OF SOUTHEAST CA...SOUTHWEST AND
SOUTH CENTRAL AZ. THIS EVENINGS UPPER AIR DATA CONTINUED TO SHOW LOW
LEVEL SOUTHWEST WINDS STILL ENTRAINING BOUNDARY LAYER MOISTURE INTO
SOUTHWEST AND SOUTH CENTRAL AZ FROM THE BAJA REGION. THIS MOISTURE
COMBINED WITH A BROAD UPPER TROF THROUGH TUESDAY WILL CONTINUE A
MARGINAL THREAT OF SHOWERS. CLEARING WEDNESDAY.

VARIABLE AMOUNTS OF BOUNDARY LAYER MOISTURE A FEW LIGHT SHOWERS
SHOULD PREVENT WIDESPREAD FOG FROM DEVELOPING OVER SOUTH CENTRAL
AZ...INCLUDING THE GREATER PHOENIX AREA TUESDAY MORNING. PATCHY AT
BEST.

MODIFICATIONS TO THIS EVENINGS FORECASTS WERE MADE EARLIER...
INCLUDING CANCELING THE FLOOD WATCH FOR SOUTH CENTRAL AZ. NO FURTHER
UPDATES NECESSARY THE REMAINDER OF TONIGHT.



.PORTIONS OF PREVIOUS DISCUSSION...333 PM MST...

A RATHER COMPLICATED UPPER TROF ALONG THE WEST COAST CONTINUED TO
AFFECT THE DESERT SOUTHWEST...INCLUDING SERN CA AND ARIZONA...EARLY
THIS AFTERNOON. UPPER LOW CENTER CONTINUED TO SPIN ALONG THE FAR
SERN CA COAST...WHILE THE MAIN COLD FRONTAL BAND PUSHED EAST AND
INTO EAST-CENTRAL ARIZONA AT 130 PM. FRONT WAS MOVING PAST CENTRAL
PHOENIX AND INTO SOUTHERN GILA COUNTY...BUT WIDESPREAD SHOWERS
CONTINUED ACROSS MOST OF MARICOPA COUNTY AS WELL AS SOUTHERN GILA
COUNTY. RADAR AND GAGE REPORTS INDICATED THAT MOST RAINFALL TOTALS
SINCE NOON WERE LESS THAN ONE THIRD OF AN INCH...AND IN FACT MOST OF
THE GAGES IN THE MARICOPA COUNTY FLOOD CONTROL DISTRICT NETWORK
MEASURED WELL BELOW ONE QUARTER INCH SINCE 1230 PM.

BY EARLY THIS EVENING...THE MAIN FOCUS OF THIS STORM SYSTEM...THE
FRONTAL BAND AND ASSOCIATED RAIN/RAIN SHOWER SHIELD...WILL PUSH EAST
AND INTO FAR EASTERN AZ AND NEW MEXICO. AT THE SAME TIME THE LOW
ALONG THE SERN CA COAST WILL WEAKEN AND BE MOVED INLAND AS A KICKER
LOW DROPS SOUTH ALONG THE CENTRAL CA COAST. AS SUCH THE CHANCES FOR
MEASURABLE PRECIP WILL DROP OFF SIGNIFICANTLY THIS EVENING...INTO
THE CHANCE CATEGORY OVER THE CENTRAL DESERTS WITH LINGERING LIKELY
POPS ACROSS SRN GILA COUNTY. AFTER MIDNIGHT TONIGHT WE EXPECT MAINLY
SINGLE DIGIT POPS ACROSS THE SWRN AZ DESERTS AS WELL AS SERN CA.
MODELS ARE CONSISTENT IN CALLING FOR THIS KICKER LOW TO DROP
SOUTHEAST TOWARDS THE NRN BAJA CA COAST TONIGHT...THEN SLOWLY DRIFT
EAST AND PASS BY ARIZONA TO THE SOUTH TUESDAY INTO WEDNESDAY. AS THE
LOW PASSES BY...DYNAMICS OVER SRN AZ BECOME WEAK...BUT SIGNIFICANT
LOW/MID LEVEL MOISTURE REMAINS IN PLACE AND AS SUCH WE WILL CONTINUE
A SLIGHT CHANCE FOR INSTABILITY SHOWERS OVER SOUTH CENTRAL AZ
TUESDAY AND TUESDAY NIGHT. IN FACT...INSTABILITY LOOKS TO BE A BIT
BETTER ON TUESDAY WITH LI VALUES GOING WEAKLY NEGATIVE AND THUS WE
HAVE A SLIGHT CHANCE FOR THUNDER IN THE FORECAST ACROSS SOUTH
CENTRAL AZ ON TUESDAY. BY WEDNESDAY AFTERNOON THE ONLY THREAT FOR
PRECIP WILL BE OVER THE HIGHER TERRAIN EAST OF PHOENIX...AND SKIES
WILL BECOME MOSTLY SUNNY FROM PHOENIX WESTWARD INTO SERN CA. TEMPS
TUESDAY AND WEDNESDAY WILLS STEADILY WARM BUT WILL REMAIN BELOW
SEASONAL NORMALS.

ONE ISSUE WE WILL CONTEND WITH TONIGHT WILL BE FOG POTENTIAL ACROSS
SOUTH CENTRAL ARIZONA. MANY LOCATIONS WILL SEE AT LEAST MODERATE
RAINFALL TOTALS TODAY...AND HUMIDITY LEVELS WILL REMAIN HIGH
OVERNIGHT. HOWEVER...WE EXPECT LINGERING LOW/MID CLOUD DECKS TONIGHT
INTO TUESDAY...REDUCING RADIATIONAL COOLING POTENTIAL. ALSO...
FORECAST SOUNDINGS ARE NOT CLASSICAL FOG SOUNDINGS. WINDS WILL BE
LIGHT BUT SHOULD NOT BE CALM FOR EXTENDED PERIODS. THUS...THERE MAY
BE PATCHY FOG WITH VISIBILITY DOWN BELOW 5 MILES AT TIMES BUT WE DO
NOT EXPECT SIGNIFICANT DENSE FOG. AS A COMPROMISE WE ADDED PATCHY
FOG TO OUR FORECAST ZONES EAST OF THE LOWER CO RIVER TONIGHT.

FOR THURSDAY...A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO THE WEEKEND...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A DECENT CHANCE FOR HIGHS IN THE 80S ACROSS THE LOWER
DESERTS BY THE WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
A BROAD COOL LOW PRESSURE SYSTEM WILL REMAIN OVER THE AREA THROUGH
TUESDAY. VARIABLE AMOUNTS OF MOISTURE WILL CONTINUE A SLIGHT THREAT
OF SHOWERS THROUGH TUESDAY EVENING...ALONG WITH SCT-BKN CLOUDS BASED
BETWEEN 6-8 THSD AGL THROUGH 20Z TUE. LIGHT WIND.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
A BROAD COOL LOW PRESSURE SYSTEM WILL REMAIN OVER THE AREA THROUGH
TUESDAY. VARIABLE AMOUNTS OF MOISTURE WILL CONTINUE SCT-BKN CLOUDS
BASED 8-12 THSD AGL THROUGH 20Z TUE. LIGHT WIND.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
STRONG HIGH PRESSURE AND MUCH DRIER CONDITIONS WILL MOVE BACK INTO
THE DISTRICT DURING THE LATTER HALF OF THE WEEK. TEMPERATURES WILL
REBOUND BACK INTO A NORMAL TO SLIGHTLY ABOVE NORMAL RANGE...WHILE
AFTERNOON HUMIDITY LEVELS RETURN INTO A 15 TO 25 PERCENT RANGE.
OVERNIGHT RECOVERY WILL BE GOOD. PERIODS OF GUSTY NORTH WINDS DOWN
THE COLORADO RIVER VALLEY WILL BE LIKELY WEDNESDAY AFTERNOON...WHILE
OCCASIONAL PERIODS OF STRONGER EASTERLY WINDS OVER RIDGE TOPS OF
CENTRAL ARIZONA MAY BE COMMON LATE IN THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH THROUGH 8 PM TODAY AZZ022>024.

CA...NONE.

&&

$$

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

DISCUSSION...VASQUEZ/CB/PERCHA
AVIATION...VASQUEZ
FIRE WEATHER...MO












000
FXUS65 KPSR 030312
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
810 PM MST MON MAR 2 2015

.SYNOPSIS...
A RELATIVELY COOL LOW PRESSURE SYSTEM WILL LINGER OVER THE REGION
THROUGH WEDNESDAY...PRODUCING PARTLY CLOUDY SKIES AND BELOW NORMAL
TEMPERATURES. A SLIGHT CHANCE OF SHOWERS ARE ALSO FORECAST ACROSS
SOUTHWEST AND SOUTH CENTRAL ARIZONA THROUGH TUESDAY EVENING.
A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY THURSDAY...INTO
THE WEEKEND AS HIGH PRESSURE SYSTEM BUILDS OVER THE DESERT
SOUTHWEST.

&&

.DISCUSSION...
AT 8 PM MST THE COLD FRONT HAD SHIFTED INTO EASTERN ARIZONA ALONG
WITH THE PRECIP BAND. IN THE WAKE OF THE COLD FRONT THIS EVENING A
FEW SHOWERS CONTINUED OVER PORTIONS OF SOUTHEAST CA...SOUTHWEST AND
SOUTH CENTRAL AZ. THIS EVENINGS UPPER AIR DATA CONTINUED TO SHOW LOW
LEVEL SOUTHWEST WINDS STILL ENTRAINING BOUNDARY LAYER MOISTURE INTO
SOUTHWEST AND SOUTH CENTRAL AZ FROM THE BAJA REGION. THIS MOISTURE
COMBINED WITH A BROAD UPPER TROF THROUGH TUESDAY WILL CONTINUE A
MARGINAL THREAT OF SHOWERS. CLEARING WEDNESDAY.

VARIABLE AMOUNTS OF BOUNDARY LAYER MOISTURE A FEW LIGHT SHOWERS
SHOULD PREVENT WIDESPREAD FOG FROM DEVELOPING OVER SOUTH CENTRAL
AZ...INCLUDING THE GREATER PHOENIX AREA TUESDAY MORNING. PATCHY AT
BEST.

MODIFICATIONS TO THIS EVENINGS FORECASTS WERE MADE EARLIER...
INCLUDING CANCELING THE FLOOD WATCH FOR SOUTH CENTRAL AZ. NO FURTHER
UPDATES NECESSARY THE REMAINDER OF TONIGHT.



.PORTIONS OF PREVIOUS DISCUSSION...333 PM MST...

A RATHER COMPLICATED UPPER TROF ALONG THE WEST COAST CONTINUED TO
AFFECT THE DESERT SOUTHWEST...INCLUDING SERN CA AND ARIZONA...EARLY
THIS AFTERNOON. UPPER LOW CENTER CONTINUED TO SPIN ALONG THE FAR
SERN CA COAST...WHILE THE MAIN COLD FRONTAL BAND PUSHED EAST AND
INTO EAST-CENTRAL ARIZONA AT 130 PM. FRONT WAS MOVING PAST CENTRAL
PHOENIX AND INTO SOUTHERN GILA COUNTY...BUT WIDESPREAD SHOWERS
CONTINUED ACROSS MOST OF MARICOPA COUNTY AS WELL AS SOUTHERN GILA
COUNTY. RADAR AND GAGE REPORTS INDICATED THAT MOST RAINFALL TOTALS
SINCE NOON WERE LESS THAN ONE THIRD OF AN INCH...AND IN FACT MOST OF
THE GAGES IN THE MARICOPA COUNTY FLOOD CONTROL DISTRICT NETWORK
MEASURED WELL BELOW ONE QUARTER INCH SINCE 1230 PM.

BY EARLY THIS EVENING...THE MAIN FOCUS OF THIS STORM SYSTEM...THE
FRONTAL BAND AND ASSOCIATED RAIN/RAIN SHOWER SHIELD...WILL PUSH EAST
AND INTO FAR EASTERN AZ AND NEW MEXICO. AT THE SAME TIME THE LOW
ALONG THE SERN CA COAST WILL WEAKEN AND BE MOVED INLAND AS A KICKER
LOW DROPS SOUTH ALONG THE CENTRAL CA COAST. AS SUCH THE CHANCES FOR
MEASURABLE PRECIP WILL DROP OFF SIGNIFICANTLY THIS EVENING...INTO
THE CHANCE CATEGORY OVER THE CENTRAL DESERTS WITH LINGERING LIKELY
POPS ACROSS SRN GILA COUNTY. AFTER MIDNIGHT TONIGHT WE EXPECT MAINLY
SINGLE DIGIT POPS ACROSS THE SWRN AZ DESERTS AS WELL AS SERN CA.
MODELS ARE CONSISTENT IN CALLING FOR THIS KICKER LOW TO DROP
SOUTHEAST TOWARDS THE NRN BAJA CA COAST TONIGHT...THEN SLOWLY DRIFT
EAST AND PASS BY ARIZONA TO THE SOUTH TUESDAY INTO WEDNESDAY. AS THE
LOW PASSES BY...DYNAMICS OVER SRN AZ BECOME WEAK...BUT SIGNIFICANT
LOW/MID LEVEL MOISTURE REMAINS IN PLACE AND AS SUCH WE WILL CONTINUE
A SLIGHT CHANCE FOR INSTABILITY SHOWERS OVER SOUTH CENTRAL AZ
TUESDAY AND TUESDAY NIGHT. IN FACT...INSTABILITY LOOKS TO BE A BIT
BETTER ON TUESDAY WITH LI VALUES GOING WEAKLY NEGATIVE AND THUS WE
HAVE A SLIGHT CHANCE FOR THUNDER IN THE FORECAST ACROSS SOUTH
CENTRAL AZ ON TUESDAY. BY WEDNESDAY AFTERNOON THE ONLY THREAT FOR
PRECIP WILL BE OVER THE HIGHER TERRAIN EAST OF PHOENIX...AND SKIES
WILL BECOME MOSTLY SUNNY FROM PHOENIX WESTWARD INTO SERN CA. TEMPS
TUESDAY AND WEDNESDAY WILLS STEADILY WARM BUT WILL REMAIN BELOW
SEASONAL NORMALS.

ONE ISSUE WE WILL CONTEND WITH TONIGHT WILL BE FOG POTENTIAL ACROSS
SOUTH CENTRAL ARIZONA. MANY LOCATIONS WILL SEE AT LEAST MODERATE
RAINFALL TOTALS TODAY...AND HUMIDITY LEVELS WILL REMAIN HIGH
OVERNIGHT. HOWEVER...WE EXPECT LINGERING LOW/MID CLOUD DECKS TONIGHT
INTO TUESDAY...REDUCING RADIATIONAL COOLING POTENTIAL. ALSO...
FORECAST SOUNDINGS ARE NOT CLASSICAL FOG SOUNDINGS. WINDS WILL BE
LIGHT BUT SHOULD NOT BE CALM FOR EXTENDED PERIODS. THUS...THERE MAY
BE PATCHY FOG WITH VISIBILITY DOWN BELOW 5 MILES AT TIMES BUT WE DO
NOT EXPECT SIGNIFICANT DENSE FOG. AS A COMPROMISE WE ADDED PATCHY
FOG TO OUR FORECAST ZONES EAST OF THE LOWER CO RIVER TONIGHT.

FOR THURSDAY...A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO THE WEEKEND...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A DECENT CHANCE FOR HIGHS IN THE 80S ACROSS THE LOWER
DESERTS BY THE WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
A BROAD COOL LOW PRESSURE SYSTEM WILL REMAIN OVER THE AREA THROUGH
TUESDAY. VARIABLE AMOUNTS OF MOISTURE WILL CONTINUE A SLIGHT THREAT
OF SHOWERS THROUGH TUESDAY EVENING...ALONG WITH SCT-BKN CLOUDS BASED
BETWEEN 6-8 THSD AGL THROUGH 20Z TUE. LIGHT WIND.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
A BROAD COOL LOW PRESSURE SYSTEM WILL REMAIN OVER THE AREA THROUGH
TUESDAY. VARIABLE AMOUNTS OF MOISTURE WILL CONTINUE SCT-BKN CLOUDS
BASED 8-12 THSD AGL THROUGH 20Z TUE. LIGHT WIND.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
STRONG HIGH PRESSURE AND MUCH DRIER CONDITIONS WILL MOVE BACK INTO
THE DISTRICT DURING THE LATTER HALF OF THE WEEK. TEMPERATURES WILL
REBOUND BACK INTO A NORMAL TO SLIGHTLY ABOVE NORMAL RANGE...WHILE
AFTERNOON HUMIDITY LEVELS RETURN INTO A 15 TO 25 PERCENT RANGE.
OVERNIGHT RECOVERY WILL BE GOOD. PERIODS OF GUSTY NORTH WINDS DOWN
THE COLORADO RIVER VALLEY WILL BE LIKELY WEDNESDAY AFTERNOON...WHILE
OCCASIONAL PERIODS OF STRONGER EASTERLY WINDS OVER RIDGE TOPS OF
CENTRAL ARIZONA MAY BE COMMON LATE IN THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH THROUGH 8 PM TODAY AZZ022>024.

CA...NONE.

&&

$$

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

DISCUSSION...VASQUEZ/CB/PERCHA
AVIATION...VASQUEZ
FIRE WEATHER...MO











000
FXUS65 KPSR 030312
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
810 PM MST MON MAR 2 2015

.SYNOPSIS...
A RELATIVELY COOL LOW PRESSURE SYSTEM WILL LINGER OVER THE REGION
THROUGH WEDNESDAY...PRODUCING PARTLY CLOUDY SKIES AND BELOW NORMAL
TEMPERATURES. A SLIGHT CHANCE OF SHOWERS ARE ALSO FORECAST ACROSS
SOUTHWEST AND SOUTH CENTRAL ARIZONA THROUGH TUESDAY EVENING.
A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY THURSDAY...INTO
THE WEEKEND AS HIGH PRESSURE SYSTEM BUILDS OVER THE DESERT
SOUTHWEST.

&&

.DISCUSSION...
AT 8 PM MST THE COLD FRONT HAD SHIFTED INTO EASTERN ARIZONA ALONG
WITH THE PRECIP BAND. IN THE WAKE OF THE COLD FRONT THIS EVENING A
FEW SHOWERS CONTINUED OVER PORTIONS OF SOUTHEAST CA...SOUTHWEST AND
SOUTH CENTRAL AZ. THIS EVENINGS UPPER AIR DATA CONTINUED TO SHOW LOW
LEVEL SOUTHWEST WINDS STILL ENTRAINING BOUNDARY LAYER MOISTURE INTO
SOUTHWEST AND SOUTH CENTRAL AZ FROM THE BAJA REGION. THIS MOISTURE
COMBINED WITH A BROAD UPPER TROF THROUGH TUESDAY WILL CONTINUE A
MARGINAL THREAT OF SHOWERS. CLEARING WEDNESDAY.

VARIABLE AMOUNTS OF BOUNDARY LAYER MOISTURE A FEW LIGHT SHOWERS
SHOULD PREVENT WIDESPREAD FOG FROM DEVELOPING OVER SOUTH CENTRAL
AZ...INCLUDING THE GREATER PHOENIX AREA TUESDAY MORNING. PATCHY AT
BEST.

MODIFICATIONS TO THIS EVENINGS FORECASTS WERE MADE EARLIER...
INCLUDING CANCELING THE FLOOD WATCH FOR SOUTH CENTRAL AZ. NO FURTHER
UPDATES NECESSARY THE REMAINDER OF TONIGHT.



.PORTIONS OF PREVIOUS DISCUSSION...333 PM MST...

A RATHER COMPLICATED UPPER TROF ALONG THE WEST COAST CONTINUED TO
AFFECT THE DESERT SOUTHWEST...INCLUDING SERN CA AND ARIZONA...EARLY
THIS AFTERNOON. UPPER LOW CENTER CONTINUED TO SPIN ALONG THE FAR
SERN CA COAST...WHILE THE MAIN COLD FRONTAL BAND PUSHED EAST AND
INTO EAST-CENTRAL ARIZONA AT 130 PM. FRONT WAS MOVING PAST CENTRAL
PHOENIX AND INTO SOUTHERN GILA COUNTY...BUT WIDESPREAD SHOWERS
CONTINUED ACROSS MOST OF MARICOPA COUNTY AS WELL AS SOUTHERN GILA
COUNTY. RADAR AND GAGE REPORTS INDICATED THAT MOST RAINFALL TOTALS
SINCE NOON WERE LESS THAN ONE THIRD OF AN INCH...AND IN FACT MOST OF
THE GAGES IN THE MARICOPA COUNTY FLOOD CONTROL DISTRICT NETWORK
MEASURED WELL BELOW ONE QUARTER INCH SINCE 1230 PM.

BY EARLY THIS EVENING...THE MAIN FOCUS OF THIS STORM SYSTEM...THE
FRONTAL BAND AND ASSOCIATED RAIN/RAIN SHOWER SHIELD...WILL PUSH EAST
AND INTO FAR EASTERN AZ AND NEW MEXICO. AT THE SAME TIME THE LOW
ALONG THE SERN CA COAST WILL WEAKEN AND BE MOVED INLAND AS A KICKER
LOW DROPS SOUTH ALONG THE CENTRAL CA COAST. AS SUCH THE CHANCES FOR
MEASURABLE PRECIP WILL DROP OFF SIGNIFICANTLY THIS EVENING...INTO
THE CHANCE CATEGORY OVER THE CENTRAL DESERTS WITH LINGERING LIKELY
POPS ACROSS SRN GILA COUNTY. AFTER MIDNIGHT TONIGHT WE EXPECT MAINLY
SINGLE DIGIT POPS ACROSS THE SWRN AZ DESERTS AS WELL AS SERN CA.
MODELS ARE CONSISTENT IN CALLING FOR THIS KICKER LOW TO DROP
SOUTHEAST TOWARDS THE NRN BAJA CA COAST TONIGHT...THEN SLOWLY DRIFT
EAST AND PASS BY ARIZONA TO THE SOUTH TUESDAY INTO WEDNESDAY. AS THE
LOW PASSES BY...DYNAMICS OVER SRN AZ BECOME WEAK...BUT SIGNIFICANT
LOW/MID LEVEL MOISTURE REMAINS IN PLACE AND AS SUCH WE WILL CONTINUE
A SLIGHT CHANCE FOR INSTABILITY SHOWERS OVER SOUTH CENTRAL AZ
TUESDAY AND TUESDAY NIGHT. IN FACT...INSTABILITY LOOKS TO BE A BIT
BETTER ON TUESDAY WITH LI VALUES GOING WEAKLY NEGATIVE AND THUS WE
HAVE A SLIGHT CHANCE FOR THUNDER IN THE FORECAST ACROSS SOUTH
CENTRAL AZ ON TUESDAY. BY WEDNESDAY AFTERNOON THE ONLY THREAT FOR
PRECIP WILL BE OVER THE HIGHER TERRAIN EAST OF PHOENIX...AND SKIES
WILL BECOME MOSTLY SUNNY FROM PHOENIX WESTWARD INTO SERN CA. TEMPS
TUESDAY AND WEDNESDAY WILLS STEADILY WARM BUT WILL REMAIN BELOW
SEASONAL NORMALS.

ONE ISSUE WE WILL CONTEND WITH TONIGHT WILL BE FOG POTENTIAL ACROSS
SOUTH CENTRAL ARIZONA. MANY LOCATIONS WILL SEE AT LEAST MODERATE
RAINFALL TOTALS TODAY...AND HUMIDITY LEVELS WILL REMAIN HIGH
OVERNIGHT. HOWEVER...WE EXPECT LINGERING LOW/MID CLOUD DECKS TONIGHT
INTO TUESDAY...REDUCING RADIATIONAL COOLING POTENTIAL. ALSO...
FORECAST SOUNDINGS ARE NOT CLASSICAL FOG SOUNDINGS. WINDS WILL BE
LIGHT BUT SHOULD NOT BE CALM FOR EXTENDED PERIODS. THUS...THERE MAY
BE PATCHY FOG WITH VISIBILITY DOWN BELOW 5 MILES AT TIMES BUT WE DO
NOT EXPECT SIGNIFICANT DENSE FOG. AS A COMPROMISE WE ADDED PATCHY
FOG TO OUR FORECAST ZONES EAST OF THE LOWER CO RIVER TONIGHT.

FOR THURSDAY...A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO THE WEEKEND...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A DECENT CHANCE FOR HIGHS IN THE 80S ACROSS THE LOWER
DESERTS BY THE WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
A BROAD COOL LOW PRESSURE SYSTEM WILL REMAIN OVER THE AREA THROUGH
TUESDAY. VARIABLE AMOUNTS OF MOISTURE WILL CONTINUE A SLIGHT THREAT
OF SHOWERS THROUGH TUESDAY EVENING...ALONG WITH SCT-BKN CLOUDS BASED
BETWEEN 6-8 THSD AGL THROUGH 20Z TUE. LIGHT WIND.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
A BROAD COOL LOW PRESSURE SYSTEM WILL REMAIN OVER THE AREA THROUGH
TUESDAY. VARIABLE AMOUNTS OF MOISTURE WILL CONTINUE SCT-BKN CLOUDS
BASED 8-12 THSD AGL THROUGH 20Z TUE. LIGHT WIND.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
STRONG HIGH PRESSURE AND MUCH DRIER CONDITIONS WILL MOVE BACK INTO
THE DISTRICT DURING THE LATTER HALF OF THE WEEK. TEMPERATURES WILL
REBOUND BACK INTO A NORMAL TO SLIGHTLY ABOVE NORMAL RANGE...WHILE
AFTERNOON HUMIDITY LEVELS RETURN INTO A 15 TO 25 PERCENT RANGE.
OVERNIGHT RECOVERY WILL BE GOOD. PERIODS OF GUSTY NORTH WINDS DOWN
THE COLORADO RIVER VALLEY WILL BE LIKELY WEDNESDAY AFTERNOON...WHILE
OCCASIONAL PERIODS OF STRONGER EASTERLY WINDS OVER RIDGE TOPS OF
CENTRAL ARIZONA MAY BE COMMON LATE IN THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH THROUGH 8 PM TODAY AZZ022>024.

CA...NONE.

&&

$$

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

DISCUSSION...VASQUEZ/CB/PERCHA
AVIATION...VASQUEZ
FIRE WEATHER...MO












000
FXUS65 KPSR 030312
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
810 PM MST MON MAR 2 2015

.SYNOPSIS...
A RELATIVELY COOL LOW PRESSURE SYSTEM WILL LINGER OVER THE REGION
THROUGH WEDNESDAY...PRODUCING PARTLY CLOUDY SKIES AND BELOW NORMAL
TEMPERATURES. A SLIGHT CHANCE OF SHOWERS ARE ALSO FORECAST ACROSS
SOUTHWEST AND SOUTH CENTRAL ARIZONA THROUGH TUESDAY EVENING.
A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY THURSDAY...INTO
THE WEEKEND AS HIGH PRESSURE SYSTEM BUILDS OVER THE DESERT
SOUTHWEST.

&&

.DISCUSSION...
AT 8 PM MST THE COLD FRONT HAD SHIFTED INTO EASTERN ARIZONA ALONG
WITH THE PRECIP BAND. IN THE WAKE OF THE COLD FRONT THIS EVENING A
FEW SHOWERS CONTINUED OVER PORTIONS OF SOUTHEAST CA...SOUTHWEST AND
SOUTH CENTRAL AZ. THIS EVENINGS UPPER AIR DATA CONTINUED TO SHOW LOW
LEVEL SOUTHWEST WINDS STILL ENTRAINING BOUNDARY LAYER MOISTURE INTO
SOUTHWEST AND SOUTH CENTRAL AZ FROM THE BAJA REGION. THIS MOISTURE
COMBINED WITH A BROAD UPPER TROF THROUGH TUESDAY WILL CONTINUE A
MARGINAL THREAT OF SHOWERS. CLEARING WEDNESDAY.

VARIABLE AMOUNTS OF BOUNDARY LAYER MOISTURE A FEW LIGHT SHOWERS
SHOULD PREVENT WIDESPREAD FOG FROM DEVELOPING OVER SOUTH CENTRAL
AZ...INCLUDING THE GREATER PHOENIX AREA TUESDAY MORNING. PATCHY AT
BEST.

MODIFICATIONS TO THIS EVENINGS FORECASTS WERE MADE EARLIER...
INCLUDING CANCELING THE FLOOD WATCH FOR SOUTH CENTRAL AZ. NO FURTHER
UPDATES NECESSARY THE REMAINDER OF TONIGHT.



.PORTIONS OF PREVIOUS DISCUSSION...333 PM MST...

A RATHER COMPLICATED UPPER TROF ALONG THE WEST COAST CONTINUED TO
AFFECT THE DESERT SOUTHWEST...INCLUDING SERN CA AND ARIZONA...EARLY
THIS AFTERNOON. UPPER LOW CENTER CONTINUED TO SPIN ALONG THE FAR
SERN CA COAST...WHILE THE MAIN COLD FRONTAL BAND PUSHED EAST AND
INTO EAST-CENTRAL ARIZONA AT 130 PM. FRONT WAS MOVING PAST CENTRAL
PHOENIX AND INTO SOUTHERN GILA COUNTY...BUT WIDESPREAD SHOWERS
CONTINUED ACROSS MOST OF MARICOPA COUNTY AS WELL AS SOUTHERN GILA
COUNTY. RADAR AND GAGE REPORTS INDICATED THAT MOST RAINFALL TOTALS
SINCE NOON WERE LESS THAN ONE THIRD OF AN INCH...AND IN FACT MOST OF
THE GAGES IN THE MARICOPA COUNTY FLOOD CONTROL DISTRICT NETWORK
MEASURED WELL BELOW ONE QUARTER INCH SINCE 1230 PM.

BY EARLY THIS EVENING...THE MAIN FOCUS OF THIS STORM SYSTEM...THE
FRONTAL BAND AND ASSOCIATED RAIN/RAIN SHOWER SHIELD...WILL PUSH EAST
AND INTO FAR EASTERN AZ AND NEW MEXICO. AT THE SAME TIME THE LOW
ALONG THE SERN CA COAST WILL WEAKEN AND BE MOVED INLAND AS A KICKER
LOW DROPS SOUTH ALONG THE CENTRAL CA COAST. AS SUCH THE CHANCES FOR
MEASURABLE PRECIP WILL DROP OFF SIGNIFICANTLY THIS EVENING...INTO
THE CHANCE CATEGORY OVER THE CENTRAL DESERTS WITH LINGERING LIKELY
POPS ACROSS SRN GILA COUNTY. AFTER MIDNIGHT TONIGHT WE EXPECT MAINLY
SINGLE DIGIT POPS ACROSS THE SWRN AZ DESERTS AS WELL AS SERN CA.
MODELS ARE CONSISTENT IN CALLING FOR THIS KICKER LOW TO DROP
SOUTHEAST TOWARDS THE NRN BAJA CA COAST TONIGHT...THEN SLOWLY DRIFT
EAST AND PASS BY ARIZONA TO THE SOUTH TUESDAY INTO WEDNESDAY. AS THE
LOW PASSES BY...DYNAMICS OVER SRN AZ BECOME WEAK...BUT SIGNIFICANT
LOW/MID LEVEL MOISTURE REMAINS IN PLACE AND AS SUCH WE WILL CONTINUE
A SLIGHT CHANCE FOR INSTABILITY SHOWERS OVER SOUTH CENTRAL AZ
TUESDAY AND TUESDAY NIGHT. IN FACT...INSTABILITY LOOKS TO BE A BIT
BETTER ON TUESDAY WITH LI VALUES GOING WEAKLY NEGATIVE AND THUS WE
HAVE A SLIGHT CHANCE FOR THUNDER IN THE FORECAST ACROSS SOUTH
CENTRAL AZ ON TUESDAY. BY WEDNESDAY AFTERNOON THE ONLY THREAT FOR
PRECIP WILL BE OVER THE HIGHER TERRAIN EAST OF PHOENIX...AND SKIES
WILL BECOME MOSTLY SUNNY FROM PHOENIX WESTWARD INTO SERN CA. TEMPS
TUESDAY AND WEDNESDAY WILLS STEADILY WARM BUT WILL REMAIN BELOW
SEASONAL NORMALS.

ONE ISSUE WE WILL CONTEND WITH TONIGHT WILL BE FOG POTENTIAL ACROSS
SOUTH CENTRAL ARIZONA. MANY LOCATIONS WILL SEE AT LEAST MODERATE
RAINFALL TOTALS TODAY...AND HUMIDITY LEVELS WILL REMAIN HIGH
OVERNIGHT. HOWEVER...WE EXPECT LINGERING LOW/MID CLOUD DECKS TONIGHT
INTO TUESDAY...REDUCING RADIATIONAL COOLING POTENTIAL. ALSO...
FORECAST SOUNDINGS ARE NOT CLASSICAL FOG SOUNDINGS. WINDS WILL BE
LIGHT BUT SHOULD NOT BE CALM FOR EXTENDED PERIODS. THUS...THERE MAY
BE PATCHY FOG WITH VISIBILITY DOWN BELOW 5 MILES AT TIMES BUT WE DO
NOT EXPECT SIGNIFICANT DENSE FOG. AS A COMPROMISE WE ADDED PATCHY
FOG TO OUR FORECAST ZONES EAST OF THE LOWER CO RIVER TONIGHT.

FOR THURSDAY...A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO THE WEEKEND...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A DECENT CHANCE FOR HIGHS IN THE 80S ACROSS THE LOWER
DESERTS BY THE WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
A BROAD COOL LOW PRESSURE SYSTEM WILL REMAIN OVER THE AREA THROUGH
TUESDAY. VARIABLE AMOUNTS OF MOISTURE WILL CONTINUE A SLIGHT THREAT
OF SHOWERS THROUGH TUESDAY EVENING...ALONG WITH SCT-BKN CLOUDS BASED
BETWEEN 6-8 THSD AGL THROUGH 20Z TUE. LIGHT WIND.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
A BROAD COOL LOW PRESSURE SYSTEM WILL REMAIN OVER THE AREA THROUGH
TUESDAY. VARIABLE AMOUNTS OF MOISTURE WILL CONTINUE SCT-BKN CLOUDS
BASED 8-12 THSD AGL THROUGH 20Z TUE. LIGHT WIND.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
STRONG HIGH PRESSURE AND MUCH DRIER CONDITIONS WILL MOVE BACK INTO
THE DISTRICT DURING THE LATTER HALF OF THE WEEK. TEMPERATURES WILL
REBOUND BACK INTO A NORMAL TO SLIGHTLY ABOVE NORMAL RANGE...WHILE
AFTERNOON HUMIDITY LEVELS RETURN INTO A 15 TO 25 PERCENT RANGE.
OVERNIGHT RECOVERY WILL BE GOOD. PERIODS OF GUSTY NORTH WINDS DOWN
THE COLORADO RIVER VALLEY WILL BE LIKELY WEDNESDAY AFTERNOON...WHILE
OCCASIONAL PERIODS OF STRONGER EASTERLY WINDS OVER RIDGE TOPS OF
CENTRAL ARIZONA MAY BE COMMON LATE IN THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH THROUGH 8 PM TODAY AZZ022>024.

CA...NONE.

&&

$$

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

DISCUSSION...VASQUEZ/CB/PERCHA
AVIATION...VASQUEZ
FIRE WEATHER...MO











000
FXUS65 KPSR 022235
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
333 PM MST MON MAR 2 2015

.UPDATE...TO AVIATION DISCUSSION...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL CONTINUE TO SHIFT EASTWARD THIS
AFTERNOON AND INTO THE EVENING HOURS TONIGHT. PERIODS OF MODERATE TO
HEAVY RAIN ARE ANTICIPATED ACROSS SOUTH CENTRAL ARIZONA...ESPECIALLY
OVER THE HIGHER TERRAIN AND FOOTHILL LOCATIONS NORTH AND EAST OF
CENTRAL PHOENIX. THERE WILL ALSO BE A SLIGHT CHANCE OF THUNDERSTORMS
AS WELL THIS AFTERNOON AND EARLY EVENING. THERE WILL ALSO BE A
LINGERING SLIGHT CHANCE FOR SHOWERS OVER SOUTH CENTRAL ARIZONA
TUESDAY INTO WEDNESDAY AS THE SYSTEM SLOWLY EXITS TO THE EAST.
COOLER TEMPERATURES WILL ACCOMPANY THIS SYSTEM WITH BELOW NORMAL
READINGS EXPECTED THROUGH MID WEEK. A RETURN TO ABOVE NORMAL
TEMPERATURES IS LIKELY BY THURSDAY AS HIGH PRESSURE BUILDS INTO THE
DESERT SOUTHWEST.

&&

.DISCUSSION...
A RATHER COMPLICATED UPPER TROF ALONG THE WEST COAST CONTINUED TO
AFFECT THE DESERT SOUTHWEST...INCLUDING SERN CA AND ARIZONA...EARLY
THIS AFTERNOON. UPPER LOW CENTER CONTINUED TO SPIN ALONG THE FAR
SERN CA COAST...WHILE THE MAIN COLD FRONTAL BAND PUSHED EAST AND
INTO EAST-CENTRAL ARIZONA AT 130 PM. FRONT WAS MOVING PAST CENTRAL
PHOENIX AND INTO SOUTHERN GILA COUNTY...BUT WIDESPREAD SHOWERS
CONTINUED ACROSS MOST OF MARICOPA COUNTY AS WELL AS SOUTHERN GILA
COUNTY. RADAR AND GAGE REPORTS INDICATED THAT MOST RAINFALL TOTALS
SINCE NOON WERE LESS THAN ONE THIRD OF AN INCH...AND IN FACT MOST OF
THE GAGES IN THE MARICOPA COUNTY FLOOD CONTROL DISTRICT NETWORK
MEASURED WELL BELOW ONE QUARTER INCH SINCE 1230 PM. SO FAR WE HAVE
NOT SEEN THUNDERSTORM DEVELOPMENT ACROSS THE CENTRAL DESERTS...BUT
AN ISOLATED STORM IS POSSIBLE THIS AFTERNOON AND INTO THE EARLY
EVENING...AND ANY STORM THAT FORMS WILL LEAD TO LOCALLY MODERATE OR
HEAVY RAINFALL. AS A RESULT...WE WILL CONTINUE THE FLOOD WATCH FOR
MARICOPA COUNTY EASTWARD...AND WE HAVE DROPPED THE WATCH FOR ALL
AREAS WEST OF MARICOPA COUNTY.

FOR THE REST OF THIS AFTERNOON...WE MAY SEE A FEW SHOWERS OR EVEN A
THUNDERSTORM REDEVELOP OVER PORTIONS OF SERN AZ AS CONVECTION SPILLS
OVER THE COASTAL RANGES...AND MOVES INLAND AND AHEAD OF THE
WEAKENING UPPER LOW ALONG THE FAR SERN CA COAST. WE DO NOT EXPECT
SIGNIFICANT PRECIP WITH ANY SHOWERS/STORMS THAT MOVE THROUGH SERN CA
HOWEVER...BUT SOME SPOTS COULD SEE AMOUNTS IN EXCESS OF ONE QUARTER
INCH.

BY EARLY THIS EVENING...THE MAIN FOCUS OF THIS STORM SYSTEM...THE
FRONTAL BAND AND ASSOCIATED RAIN/RAIN SHOWER SHIELD...WILL PUSH EAST
AND INTO FAR EASTERN AZ AND NEW MEXICO. AT THE SAME TIME THE LOW
ALONG THE SERN CA COAST WILL WEAKEN AND BE MOVED INLAND AS A KICKER
LOW DROPS SOUTH ALONG THE CENTRAL CA COAST. AS SUCH THE CHANCES FOR
MEASURABLE PRECIP WILL DROP OFF SIGNIFICANTLY THIS EVENING...INTO
THE CHANCE CATEGORY OVER THE CENTRAL DESERTS WITH LINGERING LIKELY
POPS ACROSS SRN GILA COUNTY. AFTER MIDNIGHT TONIGHT WE EXPECT MAINLY
SINGLE DIGIT POPS ACROSS THE SWRN AZ DESERTS AS WELL AS SERN CA.
MODELS ARE CONSISTENT IN CALLING FOR THIS KICKER LOW TO DROP
SOUTHEAST TOWARDS THE NRN BAJA CA COAST TONIGHT...THEN SLOWLY DRIFT
EAST AND PASS BY ARIZONA TO THE SOUTH TUESDAY INTO WEDNESDAY. AS THE
LOW PASSES BY...DYNAMICS OVER SRN AZ BECOME WEAK...BUT SIGNIFICANT
LOW/MID LEVEL MOISTURE REMAINS IN PLACE AND AS SUCH WE WILL CONTINUE
A SLIGHT CHANCE FOR INSTABILITY SHOWERS OVER SOUTH CENTRAL AZ
TUESDAY AND TUESDAY NIGHT. IN FACT...INSTABILITY LOOKS TO BE A BIT
BETTER ON TUESDAY WITH LI VALUES GOING WEAKLY NEGATIVE AND THUS WE
HAVE A SLIGHT CHANCE FOR THUNDER IN THE FORECAST ACROSS SOUTH
CENTRAL AZ ON TUESDAY. BY WEDNESDAY AFTERNOON THE ONLY THREAT FOR
PRECIP WILL BE OVER THE HIGHER TERRAIN EAST OF PHOENIX...AND SKIES
WILL BECOME MOSTLY SUNNY FROM PHOENIX WESTWARD INTO SERN CA. TEMPS
TUESDAY AND WEDNESDAY WILLS STEADILY WARM BUT WILL REMAIN BELOW
SEASONAL NORMALS.

ONE ISSUE WE WILL CONTEND WITH TONIGHT WILL BE FOG POTENTIAL ACROSS
SOUTH CENTRAL ARIZONA. MANY LOCATIONS WILL SEE AT LEAST MODERATE
RAINFALL TOTALS TODAY...AND HUMIDITY LEVELS WILL REMAIN HIGH
OVERNIGHT. HOWEVER...WE EXPECT LINGERING LOW/MID CLOUD DECKS TONIGHT
INTO TUESDAY...REDUCING RADIATIONAL COOLING POTENTIAL. ALSO...
FORECAST SOUNDINGS ARE NOT CLASSICAL FOG SOUNDINGS. WINDS WILL BE
LIGHT BUT SHOULD NOT BE CALM FOR EXTENDED PERIODS. THUS...THERE MAY
BE PATCHY FOG WITH VISIBILITY DOWN BELOW 5 MILES AT TIMES BUT WE DO
NOT EXPECT SIGNIFICANT DENSE FOG. AS A COMPROMISE WE ADDED PATCHY
FOG TO OUR FORECAST ZONES EAST OF THE LOWER CO RIVER TONIGHT.

FOR THURSDAY...A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO THE WEEKEND...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A DECENT CHANCE FOR HIGHS IN THE 80S ACROSS THE LOWER
DESERTS BY THE WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
MAIN RAIN SHOWER BAND REMAINS OVER THE EASTERN HALF OF THE PHX
METRO...WITH -SHRA/VCSH TO CONTINUE FOR KPHX...KIWA AND KSDL OVER
THE NEXT FEW HOURS. RAIN WILL CONTINUE TO TRANSITION EAST OF THE
AREA...WITH SHOWER CLEARING ALREADY NOTED ACROSS THE WESTERN
PORTIONS OF THE PHX METRO. WINDS TO GNLY HOLD POST-FRONTAL WEST TO
NORTHWEST HEADINGS WITH ELEVATED SPEEDS OF 10KTS AT LEAST...WITH
BRIEF PERIODS OF CALMER SPEEDS...UNDER 5KTS. MVFR CIGS REMAIN OVER
WESTERN MARICOPA COUNTY...DESPITE SHOWER ACTIVITY ENDING OVER THAT
AREA. CONFIDENCE IS MEDIUM IN PERIODS OF MVFR CIGS TO LINGER INTO
THE EVENING...BEFORE GRADUALLY LIFTING TOWARDS THE 5-7KFT LEVEL.
COULD SEE SOME ADDITIONAL STRAY SHOWERS DEVELOP ACROSS THE METRO
LATER IN THE EVENING...IN SIMILAR FASHION TO THE PAST COUPLE
NIGHTS...WARRANTING VCSH FOR THE EARLY EVENING.

FORECAST THOUGHTS NATURALLY TEND TOWARDS THE POTENTIAL FOR FOG
DEVELOPMENT FOR THE PHX TERMINALS...AND CRITICALLY KPHX...FOR
TUESDAY AM. WITH THE CURRENT FORECAST GUIDANCE AND SATELLITE
TRENDS...FEEL THAT WIDESPREAD SIGNIFICANT FOG DEVELOPMENT IS NOT
ANTICIPATED. SOME PATCHY FOG MAY DEVELOP FOR SOME OF THE SATELLITE
AIRFIELDS...BUT WITHIN THE PHX METRO DO NOT FEEL IFR/LIFR VSBYS WILL
BE REALIZED AT THE TERMINALS. FORECAST SOUNDINGS INDICATE SOME MID
LEVEL CLOUDS HELPING TO INSULATE OVERNIGHT TEMPERATURES...WHICH MAY
RESULT IN SOME STRATUS LAYERS ALONG NEARBY TERRAIN AND IN THE
VICINITY OF THE AIRFIELDS.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
INSTABILITY SHOWER AND ISOLATED THUNDER WILL CONTINUE ACROSS
SOUTHEAST CA IN RESPONSE TO THE ADVANCING UPPER LOW THROUGH THE
EARLY EVENING. ELEVATED WEST TO SOUTHWEST WINDS WILL ALSO PERSIST
INTO THE EVENING...WITH GUSTS UPWARDS OF 20KTS. AFTER 03/03Z OR
SO...SOME STRAY SHOWERS MAY LINGER BUT FEEL THE BULK OF THE PRECIP
ACTIVITY WILL BE WRAPPED. FEW-SCT CLOUDS 10KFT OR HIGHER MAY DRIFT
ACROSS THE AREA ALONG WITH DRIER AIR MOVING IN FROM THE WEST. THE
ADVANCE OF DRIER AIR AT THE SURFACE SHOULD HOLD OFF ANY FOG
DEVELOPMENT FOR THE MORNING HOURS...SO ATTM DO NOT HAVE ANY MENTION
IN THE TAFS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
STRONG HIGH PRESSURE AND MUCH DRIER CONDITIONS WILL MOVE BACK INTO
THE DISTRICT DURING THE LATTER HALF OF THE WEEK. TEMPERATURES WILL
REBOUND BACK INTO A NORMAL TO SLIGHTLY ABOVE NORMAL RANGE...WHILE
AFTERNOON HUMIDITY LEVELS RETURN INTO A 15 TO 25 PERCENT RANGE.
OVERNIGHT RECOVERY WILL BE GOOD. PERIODS OF GUSTY NORTH WINDS DOWN
THE COLORADO RIVER VALLEY WILL BE LIKELY WEDNESDAY AFTERNOON...WHILE
OCCASIONAL PERIODS OF STRONGER EASTERLY WINDS OVER RIDGE TOPS OF
CENTRAL ARIZONA MAY BE COMMON LATE IN THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH THROUGH 8 PM TODAY AZZ022>024.

CA...NONE.

&&

$$

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

DISCUSSION...CB/PERCHA
AVIATION...NOLTE
FIRE WEATHER...MO









000
FXUS65 KPSR 022235
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
333 PM MST MON MAR 2 2015

.UPDATE...TO AVIATION DISCUSSION...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL CONTINUE TO SHIFT EASTWARD THIS
AFTERNOON AND INTO THE EVENING HOURS TONIGHT. PERIODS OF MODERATE TO
HEAVY RAIN ARE ANTICIPATED ACROSS SOUTH CENTRAL ARIZONA...ESPECIALLY
OVER THE HIGHER TERRAIN AND FOOTHILL LOCATIONS NORTH AND EAST OF
CENTRAL PHOENIX. THERE WILL ALSO BE A SLIGHT CHANCE OF THUNDERSTORMS
AS WELL THIS AFTERNOON AND EARLY EVENING. THERE WILL ALSO BE A
LINGERING SLIGHT CHANCE FOR SHOWERS OVER SOUTH CENTRAL ARIZONA
TUESDAY INTO WEDNESDAY AS THE SYSTEM SLOWLY EXITS TO THE EAST.
COOLER TEMPERATURES WILL ACCOMPANY THIS SYSTEM WITH BELOW NORMAL
READINGS EXPECTED THROUGH MID WEEK. A RETURN TO ABOVE NORMAL
TEMPERATURES IS LIKELY BY THURSDAY AS HIGH PRESSURE BUILDS INTO THE
DESERT SOUTHWEST.

&&

.DISCUSSION...
A RATHER COMPLICATED UPPER TROF ALONG THE WEST COAST CONTINUED TO
AFFECT THE DESERT SOUTHWEST...INCLUDING SERN CA AND ARIZONA...EARLY
THIS AFTERNOON. UPPER LOW CENTER CONTINUED TO SPIN ALONG THE FAR
SERN CA COAST...WHILE THE MAIN COLD FRONTAL BAND PUSHED EAST AND
INTO EAST-CENTRAL ARIZONA AT 130 PM. FRONT WAS MOVING PAST CENTRAL
PHOENIX AND INTO SOUTHERN GILA COUNTY...BUT WIDESPREAD SHOWERS
CONTINUED ACROSS MOST OF MARICOPA COUNTY AS WELL AS SOUTHERN GILA
COUNTY. RADAR AND GAGE REPORTS INDICATED THAT MOST RAINFALL TOTALS
SINCE NOON WERE LESS THAN ONE THIRD OF AN INCH...AND IN FACT MOST OF
THE GAGES IN THE MARICOPA COUNTY FLOOD CONTROL DISTRICT NETWORK
MEASURED WELL BELOW ONE QUARTER INCH SINCE 1230 PM. SO FAR WE HAVE
NOT SEEN THUNDERSTORM DEVELOPMENT ACROSS THE CENTRAL DESERTS...BUT
AN ISOLATED STORM IS POSSIBLE THIS AFTERNOON AND INTO THE EARLY
EVENING...AND ANY STORM THAT FORMS WILL LEAD TO LOCALLY MODERATE OR
HEAVY RAINFALL. AS A RESULT...WE WILL CONTINUE THE FLOOD WATCH FOR
MARICOPA COUNTY EASTWARD...AND WE HAVE DROPPED THE WATCH FOR ALL
AREAS WEST OF MARICOPA COUNTY.

FOR THE REST OF THIS AFTERNOON...WE MAY SEE A FEW SHOWERS OR EVEN A
THUNDERSTORM REDEVELOP OVER PORTIONS OF SERN AZ AS CONVECTION SPILLS
OVER THE COASTAL RANGES...AND MOVES INLAND AND AHEAD OF THE
WEAKENING UPPER LOW ALONG THE FAR SERN CA COAST. WE DO NOT EXPECT
SIGNIFICANT PRECIP WITH ANY SHOWERS/STORMS THAT MOVE THROUGH SERN CA
HOWEVER...BUT SOME SPOTS COULD SEE AMOUNTS IN EXCESS OF ONE QUARTER
INCH.

BY EARLY THIS EVENING...THE MAIN FOCUS OF THIS STORM SYSTEM...THE
FRONTAL BAND AND ASSOCIATED RAIN/RAIN SHOWER SHIELD...WILL PUSH EAST
AND INTO FAR EASTERN AZ AND NEW MEXICO. AT THE SAME TIME THE LOW
ALONG THE SERN CA COAST WILL WEAKEN AND BE MOVED INLAND AS A KICKER
LOW DROPS SOUTH ALONG THE CENTRAL CA COAST. AS SUCH THE CHANCES FOR
MEASURABLE PRECIP WILL DROP OFF SIGNIFICANTLY THIS EVENING...INTO
THE CHANCE CATEGORY OVER THE CENTRAL DESERTS WITH LINGERING LIKELY
POPS ACROSS SRN GILA COUNTY. AFTER MIDNIGHT TONIGHT WE EXPECT MAINLY
SINGLE DIGIT POPS ACROSS THE SWRN AZ DESERTS AS WELL AS SERN CA.
MODELS ARE CONSISTENT IN CALLING FOR THIS KICKER LOW TO DROP
SOUTHEAST TOWARDS THE NRN BAJA CA COAST TONIGHT...THEN SLOWLY DRIFT
EAST AND PASS BY ARIZONA TO THE SOUTH TUESDAY INTO WEDNESDAY. AS THE
LOW PASSES BY...DYNAMICS OVER SRN AZ BECOME WEAK...BUT SIGNIFICANT
LOW/MID LEVEL MOISTURE REMAINS IN PLACE AND AS SUCH WE WILL CONTINUE
A SLIGHT CHANCE FOR INSTABILITY SHOWERS OVER SOUTH CENTRAL AZ
TUESDAY AND TUESDAY NIGHT. IN FACT...INSTABILITY LOOKS TO BE A BIT
BETTER ON TUESDAY WITH LI VALUES GOING WEAKLY NEGATIVE AND THUS WE
HAVE A SLIGHT CHANCE FOR THUNDER IN THE FORECAST ACROSS SOUTH
CENTRAL AZ ON TUESDAY. BY WEDNESDAY AFTERNOON THE ONLY THREAT FOR
PRECIP WILL BE OVER THE HIGHER TERRAIN EAST OF PHOENIX...AND SKIES
WILL BECOME MOSTLY SUNNY FROM PHOENIX WESTWARD INTO SERN CA. TEMPS
TUESDAY AND WEDNESDAY WILLS STEADILY WARM BUT WILL REMAIN BELOW
SEASONAL NORMALS.

ONE ISSUE WE WILL CONTEND WITH TONIGHT WILL BE FOG POTENTIAL ACROSS
SOUTH CENTRAL ARIZONA. MANY LOCATIONS WILL SEE AT LEAST MODERATE
RAINFALL TOTALS TODAY...AND HUMIDITY LEVELS WILL REMAIN HIGH
OVERNIGHT. HOWEVER...WE EXPECT LINGERING LOW/MID CLOUD DECKS TONIGHT
INTO TUESDAY...REDUCING RADIATIONAL COOLING POTENTIAL. ALSO...
FORECAST SOUNDINGS ARE NOT CLASSICAL FOG SOUNDINGS. WINDS WILL BE
LIGHT BUT SHOULD NOT BE CALM FOR EXTENDED PERIODS. THUS...THERE MAY
BE PATCHY FOG WITH VISIBILITY DOWN BELOW 5 MILES AT TIMES BUT WE DO
NOT EXPECT SIGNIFICANT DENSE FOG. AS A COMPROMISE WE ADDED PATCHY
FOG TO OUR FORECAST ZONES EAST OF THE LOWER CO RIVER TONIGHT.

FOR THURSDAY...A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO THE WEEKEND...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A DECENT CHANCE FOR HIGHS IN THE 80S ACROSS THE LOWER
DESERTS BY THE WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
MAIN RAIN SHOWER BAND REMAINS OVER THE EASTERN HALF OF THE PHX
METRO...WITH -SHRA/VCSH TO CONTINUE FOR KPHX...KIWA AND KSDL OVER
THE NEXT FEW HOURS. RAIN WILL CONTINUE TO TRANSITION EAST OF THE
AREA...WITH SHOWER CLEARING ALREADY NOTED ACROSS THE WESTERN
PORTIONS OF THE PHX METRO. WINDS TO GNLY HOLD POST-FRONTAL WEST TO
NORTHWEST HEADINGS WITH ELEVATED SPEEDS OF 10KTS AT LEAST...WITH
BRIEF PERIODS OF CALMER SPEEDS...UNDER 5KTS. MVFR CIGS REMAIN OVER
WESTERN MARICOPA COUNTY...DESPITE SHOWER ACTIVITY ENDING OVER THAT
AREA. CONFIDENCE IS MEDIUM IN PERIODS OF MVFR CIGS TO LINGER INTO
THE EVENING...BEFORE GRADUALLY LIFTING TOWARDS THE 5-7KFT LEVEL.
COULD SEE SOME ADDITIONAL STRAY SHOWERS DEVELOP ACROSS THE METRO
LATER IN THE EVENING...IN SIMILAR FASHION TO THE PAST COUPLE
NIGHTS...WARRANTING VCSH FOR THE EARLY EVENING.

FORECAST THOUGHTS NATURALLY TEND TOWARDS THE POTENTIAL FOR FOG
DEVELOPMENT FOR THE PHX TERMINALS...AND CRITICALLY KPHX...FOR
TUESDAY AM. WITH THE CURRENT FORECAST GUIDANCE AND SATELLITE
TRENDS...FEEL THAT WIDESPREAD SIGNIFICANT FOG DEVELOPMENT IS NOT
ANTICIPATED. SOME PATCHY FOG MAY DEVELOP FOR SOME OF THE SATELLITE
AIRFIELDS...BUT WITHIN THE PHX METRO DO NOT FEEL IFR/LIFR VSBYS WILL
BE REALIZED AT THE TERMINALS. FORECAST SOUNDINGS INDICATE SOME MID
LEVEL CLOUDS HELPING TO INSULATE OVERNIGHT TEMPERATURES...WHICH MAY
RESULT IN SOME STRATUS LAYERS ALONG NEARBY TERRAIN AND IN THE
VICINITY OF THE AIRFIELDS.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
INSTABILITY SHOWER AND ISOLATED THUNDER WILL CONTINUE ACROSS
SOUTHEAST CA IN RESPONSE TO THE ADVANCING UPPER LOW THROUGH THE
EARLY EVENING. ELEVATED WEST TO SOUTHWEST WINDS WILL ALSO PERSIST
INTO THE EVENING...WITH GUSTS UPWARDS OF 20KTS. AFTER 03/03Z OR
SO...SOME STRAY SHOWERS MAY LINGER BUT FEEL THE BULK OF THE PRECIP
ACTIVITY WILL BE WRAPPED. FEW-SCT CLOUDS 10KFT OR HIGHER MAY DRIFT
ACROSS THE AREA ALONG WITH DRIER AIR MOVING IN FROM THE WEST. THE
ADVANCE OF DRIER AIR AT THE SURFACE SHOULD HOLD OFF ANY FOG
DEVELOPMENT FOR THE MORNING HOURS...SO ATTM DO NOT HAVE ANY MENTION
IN THE TAFS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
STRONG HIGH PRESSURE AND MUCH DRIER CONDITIONS WILL MOVE BACK INTO
THE DISTRICT DURING THE LATTER HALF OF THE WEEK. TEMPERATURES WILL
REBOUND BACK INTO A NORMAL TO SLIGHTLY ABOVE NORMAL RANGE...WHILE
AFTERNOON HUMIDITY LEVELS RETURN INTO A 15 TO 25 PERCENT RANGE.
OVERNIGHT RECOVERY WILL BE GOOD. PERIODS OF GUSTY NORTH WINDS DOWN
THE COLORADO RIVER VALLEY WILL BE LIKELY WEDNESDAY AFTERNOON...WHILE
OCCASIONAL PERIODS OF STRONGER EASTERLY WINDS OVER RIDGE TOPS OF
CENTRAL ARIZONA MAY BE COMMON LATE IN THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH THROUGH 8 PM TODAY AZZ022>024.

CA...NONE.

&&

$$

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

DISCUSSION...CB/PERCHA
AVIATION...NOLTE
FIRE WEATHER...MO








000
FXUS65 KPSR 022235
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
333 PM MST MON MAR 2 2015

.UPDATE...TO AVIATION DISCUSSION...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL CONTINUE TO SHIFT EASTWARD THIS
AFTERNOON AND INTO THE EVENING HOURS TONIGHT. PERIODS OF MODERATE TO
HEAVY RAIN ARE ANTICIPATED ACROSS SOUTH CENTRAL ARIZONA...ESPECIALLY
OVER THE HIGHER TERRAIN AND FOOTHILL LOCATIONS NORTH AND EAST OF
CENTRAL PHOENIX. THERE WILL ALSO BE A SLIGHT CHANCE OF THUNDERSTORMS
AS WELL THIS AFTERNOON AND EARLY EVENING. THERE WILL ALSO BE A
LINGERING SLIGHT CHANCE FOR SHOWERS OVER SOUTH CENTRAL ARIZONA
TUESDAY INTO WEDNESDAY AS THE SYSTEM SLOWLY EXITS TO THE EAST.
COOLER TEMPERATURES WILL ACCOMPANY THIS SYSTEM WITH BELOW NORMAL
READINGS EXPECTED THROUGH MID WEEK. A RETURN TO ABOVE NORMAL
TEMPERATURES IS LIKELY BY THURSDAY AS HIGH PRESSURE BUILDS INTO THE
DESERT SOUTHWEST.

&&

.DISCUSSION...
A RATHER COMPLICATED UPPER TROF ALONG THE WEST COAST CONTINUED TO
AFFECT THE DESERT SOUTHWEST...INCLUDING SERN CA AND ARIZONA...EARLY
THIS AFTERNOON. UPPER LOW CENTER CONTINUED TO SPIN ALONG THE FAR
SERN CA COAST...WHILE THE MAIN COLD FRONTAL BAND PUSHED EAST AND
INTO EAST-CENTRAL ARIZONA AT 130 PM. FRONT WAS MOVING PAST CENTRAL
PHOENIX AND INTO SOUTHERN GILA COUNTY...BUT WIDESPREAD SHOWERS
CONTINUED ACROSS MOST OF MARICOPA COUNTY AS WELL AS SOUTHERN GILA
COUNTY. RADAR AND GAGE REPORTS INDICATED THAT MOST RAINFALL TOTALS
SINCE NOON WERE LESS THAN ONE THIRD OF AN INCH...AND IN FACT MOST OF
THE GAGES IN THE MARICOPA COUNTY FLOOD CONTROL DISTRICT NETWORK
MEASURED WELL BELOW ONE QUARTER INCH SINCE 1230 PM. SO FAR WE HAVE
NOT SEEN THUNDERSTORM DEVELOPMENT ACROSS THE CENTRAL DESERTS...BUT
AN ISOLATED STORM IS POSSIBLE THIS AFTERNOON AND INTO THE EARLY
EVENING...AND ANY STORM THAT FORMS WILL LEAD TO LOCALLY MODERATE OR
HEAVY RAINFALL. AS A RESULT...WE WILL CONTINUE THE FLOOD WATCH FOR
MARICOPA COUNTY EASTWARD...AND WE HAVE DROPPED THE WATCH FOR ALL
AREAS WEST OF MARICOPA COUNTY.

FOR THE REST OF THIS AFTERNOON...WE MAY SEE A FEW SHOWERS OR EVEN A
THUNDERSTORM REDEVELOP OVER PORTIONS OF SERN AZ AS CONVECTION SPILLS
OVER THE COASTAL RANGES...AND MOVES INLAND AND AHEAD OF THE
WEAKENING UPPER LOW ALONG THE FAR SERN CA COAST. WE DO NOT EXPECT
SIGNIFICANT PRECIP WITH ANY SHOWERS/STORMS THAT MOVE THROUGH SERN CA
HOWEVER...BUT SOME SPOTS COULD SEE AMOUNTS IN EXCESS OF ONE QUARTER
INCH.

BY EARLY THIS EVENING...THE MAIN FOCUS OF THIS STORM SYSTEM...THE
FRONTAL BAND AND ASSOCIATED RAIN/RAIN SHOWER SHIELD...WILL PUSH EAST
AND INTO FAR EASTERN AZ AND NEW MEXICO. AT THE SAME TIME THE LOW
ALONG THE SERN CA COAST WILL WEAKEN AND BE MOVED INLAND AS A KICKER
LOW DROPS SOUTH ALONG THE CENTRAL CA COAST. AS SUCH THE CHANCES FOR
MEASURABLE PRECIP WILL DROP OFF SIGNIFICANTLY THIS EVENING...INTO
THE CHANCE CATEGORY OVER THE CENTRAL DESERTS WITH LINGERING LIKELY
POPS ACROSS SRN GILA COUNTY. AFTER MIDNIGHT TONIGHT WE EXPECT MAINLY
SINGLE DIGIT POPS ACROSS THE SWRN AZ DESERTS AS WELL AS SERN CA.
MODELS ARE CONSISTENT IN CALLING FOR THIS KICKER LOW TO DROP
SOUTHEAST TOWARDS THE NRN BAJA CA COAST TONIGHT...THEN SLOWLY DRIFT
EAST AND PASS BY ARIZONA TO THE SOUTH TUESDAY INTO WEDNESDAY. AS THE
LOW PASSES BY...DYNAMICS OVER SRN AZ BECOME WEAK...BUT SIGNIFICANT
LOW/MID LEVEL MOISTURE REMAINS IN PLACE AND AS SUCH WE WILL CONTINUE
A SLIGHT CHANCE FOR INSTABILITY SHOWERS OVER SOUTH CENTRAL AZ
TUESDAY AND TUESDAY NIGHT. IN FACT...INSTABILITY LOOKS TO BE A BIT
BETTER ON TUESDAY WITH LI VALUES GOING WEAKLY NEGATIVE AND THUS WE
HAVE A SLIGHT CHANCE FOR THUNDER IN THE FORECAST ACROSS SOUTH
CENTRAL AZ ON TUESDAY. BY WEDNESDAY AFTERNOON THE ONLY THREAT FOR
PRECIP WILL BE OVER THE HIGHER TERRAIN EAST OF PHOENIX...AND SKIES
WILL BECOME MOSTLY SUNNY FROM PHOENIX WESTWARD INTO SERN CA. TEMPS
TUESDAY AND WEDNESDAY WILLS STEADILY WARM BUT WILL REMAIN BELOW
SEASONAL NORMALS.

ONE ISSUE WE WILL CONTEND WITH TONIGHT WILL BE FOG POTENTIAL ACROSS
SOUTH CENTRAL ARIZONA. MANY LOCATIONS WILL SEE AT LEAST MODERATE
RAINFALL TOTALS TODAY...AND HUMIDITY LEVELS WILL REMAIN HIGH
OVERNIGHT. HOWEVER...WE EXPECT LINGERING LOW/MID CLOUD DECKS TONIGHT
INTO TUESDAY...REDUCING RADIATIONAL COOLING POTENTIAL. ALSO...
FORECAST SOUNDINGS ARE NOT CLASSICAL FOG SOUNDINGS. WINDS WILL BE
LIGHT BUT SHOULD NOT BE CALM FOR EXTENDED PERIODS. THUS...THERE MAY
BE PATCHY FOG WITH VISIBILITY DOWN BELOW 5 MILES AT TIMES BUT WE DO
NOT EXPECT SIGNIFICANT DENSE FOG. AS A COMPROMISE WE ADDED PATCHY
FOG TO OUR FORECAST ZONES EAST OF THE LOWER CO RIVER TONIGHT.

FOR THURSDAY...A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO THE WEEKEND...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A DECENT CHANCE FOR HIGHS IN THE 80S ACROSS THE LOWER
DESERTS BY THE WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
MAIN RAIN SHOWER BAND REMAINS OVER THE EASTERN HALF OF THE PHX
METRO...WITH -SHRA/VCSH TO CONTINUE FOR KPHX...KIWA AND KSDL OVER
THE NEXT FEW HOURS. RAIN WILL CONTINUE TO TRANSITION EAST OF THE
AREA...WITH SHOWER CLEARING ALREADY NOTED ACROSS THE WESTERN
PORTIONS OF THE PHX METRO. WINDS TO GNLY HOLD POST-FRONTAL WEST TO
NORTHWEST HEADINGS WITH ELEVATED SPEEDS OF 10KTS AT LEAST...WITH
BRIEF PERIODS OF CALMER SPEEDS...UNDER 5KTS. MVFR CIGS REMAIN OVER
WESTERN MARICOPA COUNTY...DESPITE SHOWER ACTIVITY ENDING OVER THAT
AREA. CONFIDENCE IS MEDIUM IN PERIODS OF MVFR CIGS TO LINGER INTO
THE EVENING...BEFORE GRADUALLY LIFTING TOWARDS THE 5-7KFT LEVEL.
COULD SEE SOME ADDITIONAL STRAY SHOWERS DEVELOP ACROSS THE METRO
LATER IN THE EVENING...IN SIMILAR FASHION TO THE PAST COUPLE
NIGHTS...WARRANTING VCSH FOR THE EARLY EVENING.

FORECAST THOUGHTS NATURALLY TEND TOWARDS THE POTENTIAL FOR FOG
DEVELOPMENT FOR THE PHX TERMINALS...AND CRITICALLY KPHX...FOR
TUESDAY AM. WITH THE CURRENT FORECAST GUIDANCE AND SATELLITE
TRENDS...FEEL THAT WIDESPREAD SIGNIFICANT FOG DEVELOPMENT IS NOT
ANTICIPATED. SOME PATCHY FOG MAY DEVELOP FOR SOME OF THE SATELLITE
AIRFIELDS...BUT WITHIN THE PHX METRO DO NOT FEEL IFR/LIFR VSBYS WILL
BE REALIZED AT THE TERMINALS. FORECAST SOUNDINGS INDICATE SOME MID
LEVEL CLOUDS HELPING TO INSULATE OVERNIGHT TEMPERATURES...WHICH MAY
RESULT IN SOME STRATUS LAYERS ALONG NEARBY TERRAIN AND IN THE
VICINITY OF THE AIRFIELDS.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
INSTABILITY SHOWER AND ISOLATED THUNDER WILL CONTINUE ACROSS
SOUTHEAST CA IN RESPONSE TO THE ADVANCING UPPER LOW THROUGH THE
EARLY EVENING. ELEVATED WEST TO SOUTHWEST WINDS WILL ALSO PERSIST
INTO THE EVENING...WITH GUSTS UPWARDS OF 20KTS. AFTER 03/03Z OR
SO...SOME STRAY SHOWERS MAY LINGER BUT FEEL THE BULK OF THE PRECIP
ACTIVITY WILL BE WRAPPED. FEW-SCT CLOUDS 10KFT OR HIGHER MAY DRIFT
ACROSS THE AREA ALONG WITH DRIER AIR MOVING IN FROM THE WEST. THE
ADVANCE OF DRIER AIR AT THE SURFACE SHOULD HOLD OFF ANY FOG
DEVELOPMENT FOR THE MORNING HOURS...SO ATTM DO NOT HAVE ANY MENTION
IN THE TAFS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
STRONG HIGH PRESSURE AND MUCH DRIER CONDITIONS WILL MOVE BACK INTO
THE DISTRICT DURING THE LATTER HALF OF THE WEEK. TEMPERATURES WILL
REBOUND BACK INTO A NORMAL TO SLIGHTLY ABOVE NORMAL RANGE...WHILE
AFTERNOON HUMIDITY LEVELS RETURN INTO A 15 TO 25 PERCENT RANGE.
OVERNIGHT RECOVERY WILL BE GOOD. PERIODS OF GUSTY NORTH WINDS DOWN
THE COLORADO RIVER VALLEY WILL BE LIKELY WEDNESDAY AFTERNOON...WHILE
OCCASIONAL PERIODS OF STRONGER EASTERLY WINDS OVER RIDGE TOPS OF
CENTRAL ARIZONA MAY BE COMMON LATE IN THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH THROUGH 8 PM TODAY AZZ022>024.

CA...NONE.

&&

$$

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

DISCUSSION...CB/PERCHA
AVIATION...NOLTE
FIRE WEATHER...MO









000
FXUS65 KPSR 022235
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
333 PM MST MON MAR 2 2015

.UPDATE...TO AVIATION DISCUSSION...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL CONTINUE TO SHIFT EASTWARD THIS
AFTERNOON AND INTO THE EVENING HOURS TONIGHT. PERIODS OF MODERATE TO
HEAVY RAIN ARE ANTICIPATED ACROSS SOUTH CENTRAL ARIZONA...ESPECIALLY
OVER THE HIGHER TERRAIN AND FOOTHILL LOCATIONS NORTH AND EAST OF
CENTRAL PHOENIX. THERE WILL ALSO BE A SLIGHT CHANCE OF THUNDERSTORMS
AS WELL THIS AFTERNOON AND EARLY EVENING. THERE WILL ALSO BE A
LINGERING SLIGHT CHANCE FOR SHOWERS OVER SOUTH CENTRAL ARIZONA
TUESDAY INTO WEDNESDAY AS THE SYSTEM SLOWLY EXITS TO THE EAST.
COOLER TEMPERATURES WILL ACCOMPANY THIS SYSTEM WITH BELOW NORMAL
READINGS EXPECTED THROUGH MID WEEK. A RETURN TO ABOVE NORMAL
TEMPERATURES IS LIKELY BY THURSDAY AS HIGH PRESSURE BUILDS INTO THE
DESERT SOUTHWEST.

&&

.DISCUSSION...
A RATHER COMPLICATED UPPER TROF ALONG THE WEST COAST CONTINUED TO
AFFECT THE DESERT SOUTHWEST...INCLUDING SERN CA AND ARIZONA...EARLY
THIS AFTERNOON. UPPER LOW CENTER CONTINUED TO SPIN ALONG THE FAR
SERN CA COAST...WHILE THE MAIN COLD FRONTAL BAND PUSHED EAST AND
INTO EAST-CENTRAL ARIZONA AT 130 PM. FRONT WAS MOVING PAST CENTRAL
PHOENIX AND INTO SOUTHERN GILA COUNTY...BUT WIDESPREAD SHOWERS
CONTINUED ACROSS MOST OF MARICOPA COUNTY AS WELL AS SOUTHERN GILA
COUNTY. RADAR AND GAGE REPORTS INDICATED THAT MOST RAINFALL TOTALS
SINCE NOON WERE LESS THAN ONE THIRD OF AN INCH...AND IN FACT MOST OF
THE GAGES IN THE MARICOPA COUNTY FLOOD CONTROL DISTRICT NETWORK
MEASURED WELL BELOW ONE QUARTER INCH SINCE 1230 PM. SO FAR WE HAVE
NOT SEEN THUNDERSTORM DEVELOPMENT ACROSS THE CENTRAL DESERTS...BUT
AN ISOLATED STORM IS POSSIBLE THIS AFTERNOON AND INTO THE EARLY
EVENING...AND ANY STORM THAT FORMS WILL LEAD TO LOCALLY MODERATE OR
HEAVY RAINFALL. AS A RESULT...WE WILL CONTINUE THE FLOOD WATCH FOR
MARICOPA COUNTY EASTWARD...AND WE HAVE DROPPED THE WATCH FOR ALL
AREAS WEST OF MARICOPA COUNTY.

FOR THE REST OF THIS AFTERNOON...WE MAY SEE A FEW SHOWERS OR EVEN A
THUNDERSTORM REDEVELOP OVER PORTIONS OF SERN AZ AS CONVECTION SPILLS
OVER THE COASTAL RANGES...AND MOVES INLAND AND AHEAD OF THE
WEAKENING UPPER LOW ALONG THE FAR SERN CA COAST. WE DO NOT EXPECT
SIGNIFICANT PRECIP WITH ANY SHOWERS/STORMS THAT MOVE THROUGH SERN CA
HOWEVER...BUT SOME SPOTS COULD SEE AMOUNTS IN EXCESS OF ONE QUARTER
INCH.

BY EARLY THIS EVENING...THE MAIN FOCUS OF THIS STORM SYSTEM...THE
FRONTAL BAND AND ASSOCIATED RAIN/RAIN SHOWER SHIELD...WILL PUSH EAST
AND INTO FAR EASTERN AZ AND NEW MEXICO. AT THE SAME TIME THE LOW
ALONG THE SERN CA COAST WILL WEAKEN AND BE MOVED INLAND AS A KICKER
LOW DROPS SOUTH ALONG THE CENTRAL CA COAST. AS SUCH THE CHANCES FOR
MEASURABLE PRECIP WILL DROP OFF SIGNIFICANTLY THIS EVENING...INTO
THE CHANCE CATEGORY OVER THE CENTRAL DESERTS WITH LINGERING LIKELY
POPS ACROSS SRN GILA COUNTY. AFTER MIDNIGHT TONIGHT WE EXPECT MAINLY
SINGLE DIGIT POPS ACROSS THE SWRN AZ DESERTS AS WELL AS SERN CA.
MODELS ARE CONSISTENT IN CALLING FOR THIS KICKER LOW TO DROP
SOUTHEAST TOWARDS THE NRN BAJA CA COAST TONIGHT...THEN SLOWLY DRIFT
EAST AND PASS BY ARIZONA TO THE SOUTH TUESDAY INTO WEDNESDAY. AS THE
LOW PASSES BY...DYNAMICS OVER SRN AZ BECOME WEAK...BUT SIGNIFICANT
LOW/MID LEVEL MOISTURE REMAINS IN PLACE AND AS SUCH WE WILL CONTINUE
A SLIGHT CHANCE FOR INSTABILITY SHOWERS OVER SOUTH CENTRAL AZ
TUESDAY AND TUESDAY NIGHT. IN FACT...INSTABILITY LOOKS TO BE A BIT
BETTER ON TUESDAY WITH LI VALUES GOING WEAKLY NEGATIVE AND THUS WE
HAVE A SLIGHT CHANCE FOR THUNDER IN THE FORECAST ACROSS SOUTH
CENTRAL AZ ON TUESDAY. BY WEDNESDAY AFTERNOON THE ONLY THREAT FOR
PRECIP WILL BE OVER THE HIGHER TERRAIN EAST OF PHOENIX...AND SKIES
WILL BECOME MOSTLY SUNNY FROM PHOENIX WESTWARD INTO SERN CA. TEMPS
TUESDAY AND WEDNESDAY WILLS STEADILY WARM BUT WILL REMAIN BELOW
SEASONAL NORMALS.

ONE ISSUE WE WILL CONTEND WITH TONIGHT WILL BE FOG POTENTIAL ACROSS
SOUTH CENTRAL ARIZONA. MANY LOCATIONS WILL SEE AT LEAST MODERATE
RAINFALL TOTALS TODAY...AND HUMIDITY LEVELS WILL REMAIN HIGH
OVERNIGHT. HOWEVER...WE EXPECT LINGERING LOW/MID CLOUD DECKS TONIGHT
INTO TUESDAY...REDUCING RADIATIONAL COOLING POTENTIAL. ALSO...
FORECAST SOUNDINGS ARE NOT CLASSICAL FOG SOUNDINGS. WINDS WILL BE
LIGHT BUT SHOULD NOT BE CALM FOR EXTENDED PERIODS. THUS...THERE MAY
BE PATCHY FOG WITH VISIBILITY DOWN BELOW 5 MILES AT TIMES BUT WE DO
NOT EXPECT SIGNIFICANT DENSE FOG. AS A COMPROMISE WE ADDED PATCHY
FOG TO OUR FORECAST ZONES EAST OF THE LOWER CO RIVER TONIGHT.

FOR THURSDAY...A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEAD TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO THE WEEKEND...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A DECENT CHANCE FOR HIGHS IN THE 80S ACROSS THE LOWER
DESERTS BY THE WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
MAIN RAIN SHOWER BAND REMAINS OVER THE EASTERN HALF OF THE PHX
METRO...WITH -SHRA/VCSH TO CONTINUE FOR KPHX...KIWA AND KSDL OVER
THE NEXT FEW HOURS. RAIN WILL CONTINUE TO TRANSITION EAST OF THE
AREA...WITH SHOWER CLEARING ALREADY NOTED ACROSS THE WESTERN
PORTIONS OF THE PHX METRO. WINDS TO GNLY HOLD POST-FRONTAL WEST TO
NORTHWEST HEADINGS WITH ELEVATED SPEEDS OF 10KTS AT LEAST...WITH
BRIEF PERIODS OF CALMER SPEEDS...UNDER 5KTS. MVFR CIGS REMAIN OVER
WESTERN MARICOPA COUNTY...DESPITE SHOWER ACTIVITY ENDING OVER THAT
AREA. CONFIDENCE IS MEDIUM IN PERIODS OF MVFR CIGS TO LINGER INTO
THE EVENING...BEFORE GRADUALLY LIFTING TOWARDS THE 5-7KFT LEVEL.
COULD SEE SOME ADDITIONAL STRAY SHOWERS DEVELOP ACROSS THE METRO
LATER IN THE EVENING...IN SIMILAR FASHION TO THE PAST COUPLE
NIGHTS...WARRANTING VCSH FOR THE EARLY EVENING.

FORECAST THOUGHTS NATURALLY TEND TOWARDS THE POTENTIAL FOR FOG
DEVELOPMENT FOR THE PHX TERMINALS...AND CRITICALLY KPHX...FOR
TUESDAY AM. WITH THE CURRENT FORECAST GUIDANCE AND SATELLITE
TRENDS...FEEL THAT WIDESPREAD SIGNIFICANT FOG DEVELOPMENT IS NOT
ANTICIPATED. SOME PATCHY FOG MAY DEVELOP FOR SOME OF THE SATELLITE
AIRFIELDS...BUT WITHIN THE PHX METRO DO NOT FEEL IFR/LIFR VSBYS WILL
BE REALIZED AT THE TERMINALS. FORECAST SOUNDINGS INDICATE SOME MID
LEVEL CLOUDS HELPING TO INSULATE OVERNIGHT TEMPERATURES...WHICH MAY
RESULT IN SOME STRATUS LAYERS ALONG NEARBY TERRAIN AND IN THE
VICINITY OF THE AIRFIELDS.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
INSTABILITY SHOWER AND ISOLATED THUNDER WILL CONTINUE ACROSS
SOUTHEAST CA IN RESPONSE TO THE ADVANCING UPPER LOW THROUGH THE
EARLY EVENING. ELEVATED WEST TO SOUTHWEST WINDS WILL ALSO PERSIST
INTO THE EVENING...WITH GUSTS UPWARDS OF 20KTS. AFTER 03/03Z OR
SO...SOME STRAY SHOWERS MAY LINGER BUT FEEL THE BULK OF THE PRECIP
ACTIVITY WILL BE WRAPPED. FEW-SCT CLOUDS 10KFT OR HIGHER MAY DRIFT
ACROSS THE AREA ALONG WITH DRIER AIR MOVING IN FROM THE WEST. THE
ADVANCE OF DRIER AIR AT THE SURFACE SHOULD HOLD OFF ANY FOG
DEVELOPMENT FOR THE MORNING HOURS...SO ATTM DO NOT HAVE ANY MENTION
IN THE TAFS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
STRONG HIGH PRESSURE AND MUCH DRIER CONDITIONS WILL MOVE BACK INTO
THE DISTRICT DURING THE LATTER HALF OF THE WEEK. TEMPERATURES WILL
REBOUND BACK INTO A NORMAL TO SLIGHTLY ABOVE NORMAL RANGE...WHILE
AFTERNOON HUMIDITY LEVELS RETURN INTO A 15 TO 25 PERCENT RANGE.
OVERNIGHT RECOVERY WILL BE GOOD. PERIODS OF GUSTY NORTH WINDS DOWN
THE COLORADO RIVER VALLEY WILL BE LIKELY WEDNESDAY AFTERNOON...WHILE
OCCASIONAL PERIODS OF STRONGER EASTERLY WINDS OVER RIDGE TOPS OF
CENTRAL ARIZONA MAY BE COMMON LATE IN THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH THROUGH 8 PM TODAY AZZ022>024.

CA...NONE.

&&

$$

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

DISCUSSION...CB/PERCHA
AVIATION...NOLTE
FIRE WEATHER...MO








000
FXUS65 KPSR 022125
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
225 PM MST MON MAR 2 2015

...POTENTIAL FOR HEAVY RAIN AFFECTING SOUTH CENTRAL AZ THROUGH THE
EARLY EVENING HOURS TODAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL CONTINUE TO SHIFT EASTWARD THIS
AFTERNOON AND INTO THE EVENING HOURS TONIGHT. PERIODS OF MODERATE TO
HEAVY RAIN ARE ANTICIPATED ACROSS SOUTH CENTRAL ARIZONA...ESPECIALLY
OVER THE HIGHER TERRAIN AND FOOTHILL LOCATIONS NORTH AND EAST OF
CENTRAL PHOENIX. THERE WILL ALSO BE A SLIGHT CHANCE OF THUNDERSTORMS
AS WELL THIS AFTERNOON AND EARLY EVENING. THERE WILL ALSO BE A
LINGERING SLIGHT CHANCE FOR SHOWERS OVER SOUTH CENTRAL ARIZONA
TUESDAY INTO WEDNESDAY AS THE SYSTEM SLOWLY EXITS TO THE EAST.
COOLER TEMPERATURES WILL ACCOMPANY THIS SYSTEM WITH BELOW NORMAL
READINGS EXPECTED THROUGH MID WEEK. A RETURN TO ABOVE NORMAL
TEMPERATURES IS LIKELY BY THURSDAY AS HIGH PRESSURE BUILDS INTO THE
DESERT SOUTHWEST.

&&

.DISCUSSION...
A RATHER COMPLICATED UPPER TROF ALONG THE WEST COAST CONTINUED TO
AFFECT THE DESERT SOUTHWEST...INCLUDING SERN CA AND ARIZONA...EARLY
THIS AFTERNOON. UPPER LOW CENTER CONTINUED TO SPIN ALONG THE FAR
SERN CA COAST...WHILE THE MAIN COLD FRONTAL BAND PUSHED EAST AND
INTO EAST-CENTRAL ARIZONA AT 130 PM. FRONT WAS MOVING PAST CENTRAL
PHOENIX AND INTO SOUTHERN GILA COUNTY...BUT WIDESPREAD SHOWERS
CONTINUED ACROSS MOST OF MARICOPA COUNTY AS WELL AS SOUTHERN GILA
COUNTY. RADAR AND GAGE REPORTS INDICATED THAT MOST RAINFALL TOTALS
SINCE NOON WERE LESS THAN ONE THIRD OF AN INCH...AND IN FACT MOST OF
THE GAGES IN THE MARICOPA COUNTY FLOOD CONTROL DISTRICT NETWORK
MEASURED WELL BELOW ONE QUARTER INCH SINCE 1230 PM. SO FAR WE HAVE
NOT SEEN THUNDERSTORM DEVELOPMENT ACROSS THE CENTRAL DESERTS...BUT
AN ISOLATED STORM IS POSSIBLE THIS AFTERNOON AND INTO THE EARLY
EVENING...AND ANY STORM THAT FORMS WILL LEAD TO LOCALLY MODERATE OR
HEAVY RAINFALL. AS A RESULT...WE WILL CONTINUE THE FLOOD WATCH FOR
MARICOPA COUNTY EASTWARD...AND WE HAVE DROPPED THE WATCH FOR ALL
AREAS WEST OF MARICOPA COUNTY.

FOR THE REST OF THIS AFTERNOON...WE MAY SEE A FEW SHOWERS OR EVEN A
THUNDERSTORM REDEVELOP OVER PORTIONS OF SERN AZ AS CONVECTION SPILLS
OVER THE COASTAL RANGES...AND MOVES INLAND AND AHEAD OF THE
WEAKENING UPPER LOW ALONG THE FAR SERN CA COAST. WE DO NOT EXPECT
SIGNIFICANT PRECIP WITH ANY SHOWERS/STORMS THAT MOVE THROUGH SERN CA
HOWEVER...BUT SOME SPOTS COULD SEE AMOUNTS IN EXCESS OF ONE QUARTER
INCH.

BY EARLY THIS EVENING...THE MAIN FOCUS OF THIS STORM SYSTEM...THE
FRONTAL BAND AND ASSOCIATED RAIN/RAIN SHOWER SHIELD...WILL PUSH EAST
AND INTO FAR EASTERN AZ AND NEW MEXICO. AT THE SAME TIME THE LOW
ALONG THE SERN CA COAST WILL WEAKEN AND BE MOVED INLAND AS A KICKER
LOW DROPS SOUTH ALONG THE CENTRAL CA COAST. AS SUCH THE CHANCES FOR
MEASURABLE PRECIP WILL DROP OFF SIGNIFICANTLY THIS EVENING...INTO
THE CHANCE CATEGORY OVER THE CENTRAL DESERTS WITH LINGERING LIKELY
POPS ACROSS SRN GILA COUNTY. AFTER MIDNIGHT TONIGHT WE EXPECT MAINLY
SINGLE DIGIT POPS ACROSS THE SWRN AZ DESERTS AS WELL AS SERN CA.
MODELS ARE CONSISTENT IN CALLING FOR THIS KICKER LOW TO DROP
SOUTHEAST TOWARDS THE NRN BAJA CA COAST TONIGHT...THEN SLOWLY DRIFT
EAST AND PASS BY ARIZONA TO THE SOUTH TUESDAY INTO WEDNESDAY. AS THE
LOW PASSES BY...DYNAMICS OVER SRN AZ BECOME WEAK...BUT SIGNIFICANT
LOW/MID LEVEL MOISTURE REMAINS IN PLACE AND AS SUCH WE WILL CONTINUE
A SLIGHT CHANCE FOR INSTABILITY SHOWERS OVER SOUTH CENTRAL AZ
TUESDAY AND TUESDAY NIGHT. IN FACT...INSTABILITY LOOKS TO BE A BIT
BETTER ON TUESDAY WITH LI VALUES GOING WEAKLY NEGATIVE AND THUS WE
HAVE A SLIGHT CHANCE FOR THUNDER IN THE FORECAST ACROSS SOUTH
CENTRAL AZ ON TUESDAY. BY WEDNESDAY AFTERNOON THE ONLY THREAT FOR
PRECIP WILL BE OVER THE HIGHER TERRAIN EAST OF PHOENIX...AND SKIES
WILL BECOME MOSTLY SUNNY FROM PHOENIX WESTWARD INTO SERN CA. TEMPS
TUESDAY AND WEDNESDAY WILLS STEADILY WARM BUT WILL REMAIN BELOW
SEASONAL NORMALS.

ONE ISSUE WE WILL CONTEND WITH TONIGHT WILL BE FOG POTENTIAL ACROSS
SOUTH CENTRAL ARIZONA. MANY LOCATIONS WILL SEE AT LEAST MODERATE
RAINFALL TOTALS TODAY...AND HUMIDITY LEVELS WILL REMAIN HIGH
OVERNIGHT. HOWEVER...WE EXPECT LINGERING LOW/MID CLOUD DECKS TONIGHT
INTO TUESDAY...REDUCING RADITIONAL COOLING POTENTIAL. ALSO...
FORECAST SOUNDINGS ARE NOT CLASSICAL FOG SOUNDINGS. WINDS WILL BE
LIGHT BUT SHOULD NOT BE CALM FOR EXTENDED PERIODS. THUS...THERE MAY
BE PATCHY FOG WITH VISIBILITY DOWN BELOW 5 MILES AT TIMES BUT WE DO
NOT EXPECT SIGNIFICANT DENSE FOG. AS A COMPROMISE WE ADDED PATCHY
FOG TO OUR FORECAST ZONES EAST OF THE LOWER CO RIVER TONIGHT.

FOR THURSDAY...A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEADY TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO THE WEEKEND...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A DECENT CHANCE FOR HIGHS IN THE 80S ACROSS THE LOWER
DESERTS BY THE WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
WIDESPREAD IMPACTS INCLUDING LOW CIGS...RAIN SHOWERS...LOWERED
VSBY...AND GUSTY WIND SHIFTS WILL BE COMMON ACROSS CNTRL ARIZONA
TERMINALS THROUGH THIS AFTERNOON. CIGS HAVE ALREADY STARTED LOWERING
BLO 6K FT WITH MTN OBSCURATION PREVAILING THROUGH THE DAY.
CONFIDENCE IS ONLY MODEST IN TIMING THE HEAVIEST SQUALLS INTO
KPHX...THOUGH MOST HIGH RESOLUTION MODELS SUGGEST A COUPLE HOURS
AROUND 18Z WITH PREVAILING MVFR CONDITIONS ALONG WITH A DISTINCT
WIND SHIFT. SOME BRIEF PERIODS OF IFR MAY ALSO BE POSSIBLE IN THE
HEAVIEST SHOWERS...THOUGH CONFIDENCE AND TEMPORAL DURATION TOO LOW
TO MENTION IN THIS TAF PACKAGE. CONFIDENCE IS VERY LOW BEYOND
00Z...AND SOME ADDITIONAL SCT SHRA AND CIGS FALLING BACK BLO 6K FT
MAY BE POSSIBLE.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
PREVAILING RAIN WILL MOVE EAST OF TERMINAL SITES BY 15Z...HOWEVER
LINGER LOW LEVEL MOISTURE HAS ALLOWED PATCHY MVFR TO LIFR CIGS TO
DEVELOP. NOT A LOT OF CONFIDENCE IN HOW LONG THESE LOWER CATEGORIES
WILL PERSIST...THOUGH MODELS SUGGEST ONLY A BRIEF TIME. WITH THE
UPPER LEVEL SYSTEM MOVING THROUGH SOUTHEAST CALIFORNIA THIS
AFTERNOON...CONFIDENCE IS BETTER THAN GUSTY WEST WINDS WILL DEVELOP
WITH SOME SHRA REDEVELOPMENT. CONDITIONS WILL IMPROVE QUICKLY AFTER
SUNSET.


AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
STRONG HIGH PRESSURE AND MUCH DRIER CONDITIONS WILL MOVE BACK INTO
THE DISTRICT DURING THE LATTER HALF OF THE WEEK. TEMPERATURES WILL
REBOUND BACK INTO A NORMAL TO SLIGHTLY ABOVE NORMAL RANGE...WHILE
AFTERNOON HUMIDITY LEVELS RETURN INTO A 15 TO 25 PERCENT RANGE.
OVERNIGHT RECOVERY WILL BE GOOD. PERIODS OF GUSTY NORTH WINDS DOWN
THE COLORADO RIVER VALLEY WILL BE LIKELY WEDNESDAY AFTERNOON...WHILE
OCCASIONAL PERIODS OF STRONGER EASTERLY WINDS OVER RIDGE TOPS OF
CENTRAL ARIZONA MAY BE COMMON LATE IN THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH THROUGH 8 PM TODAY AZZ022>024.

CA...NONE.

&&

$$

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

DISCUSSION...CB/PERCHA
AVIATION...MO
FIRE WEATHER...MO














000
FXUS65 KPSR 022125
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
225 PM MST MON MAR 2 2015

...POTENTIAL FOR HEAVY RAIN AFFECTING SOUTH CENTRAL AZ THROUGH THE
EARLY EVENING HOURS TODAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL CONTINUE TO SHIFT EASTWARD THIS
AFTERNOON AND INTO THE EVENING HOURS TONIGHT. PERIODS OF MODERATE TO
HEAVY RAIN ARE ANTICIPATED ACROSS SOUTH CENTRAL ARIZONA...ESPECIALLY
OVER THE HIGHER TERRAIN AND FOOTHILL LOCATIONS NORTH AND EAST OF
CENTRAL PHOENIX. THERE WILL ALSO BE A SLIGHT CHANCE OF THUNDERSTORMS
AS WELL THIS AFTERNOON AND EARLY EVENING. THERE WILL ALSO BE A
LINGERING SLIGHT CHANCE FOR SHOWERS OVER SOUTH CENTRAL ARIZONA
TUESDAY INTO WEDNESDAY AS THE SYSTEM SLOWLY EXITS TO THE EAST.
COOLER TEMPERATURES WILL ACCOMPANY THIS SYSTEM WITH BELOW NORMAL
READINGS EXPECTED THROUGH MID WEEK. A RETURN TO ABOVE NORMAL
TEMPERATURES IS LIKELY BY THURSDAY AS HIGH PRESSURE BUILDS INTO THE
DESERT SOUTHWEST.

&&

.DISCUSSION...
A RATHER COMPLICATED UPPER TROF ALONG THE WEST COAST CONTINUED TO
AFFECT THE DESERT SOUTHWEST...INCLUDING SERN CA AND ARIZONA...EARLY
THIS AFTERNOON. UPPER LOW CENTER CONTINUED TO SPIN ALONG THE FAR
SERN CA COAST...WHILE THE MAIN COLD FRONTAL BAND PUSHED EAST AND
INTO EAST-CENTRAL ARIZONA AT 130 PM. FRONT WAS MOVING PAST CENTRAL
PHOENIX AND INTO SOUTHERN GILA COUNTY...BUT WIDESPREAD SHOWERS
CONTINUED ACROSS MOST OF MARICOPA COUNTY AS WELL AS SOUTHERN GILA
COUNTY. RADAR AND GAGE REPORTS INDICATED THAT MOST RAINFALL TOTALS
SINCE NOON WERE LESS THAN ONE THIRD OF AN INCH...AND IN FACT MOST OF
THE GAGES IN THE MARICOPA COUNTY FLOOD CONTROL DISTRICT NETWORK
MEASURED WELL BELOW ONE QUARTER INCH SINCE 1230 PM. SO FAR WE HAVE
NOT SEEN THUNDERSTORM DEVELOPMENT ACROSS THE CENTRAL DESERTS...BUT
AN ISOLATED STORM IS POSSIBLE THIS AFTERNOON AND INTO THE EARLY
EVENING...AND ANY STORM THAT FORMS WILL LEAD TO LOCALLY MODERATE OR
HEAVY RAINFALL. AS A RESULT...WE WILL CONTINUE THE FLOOD WATCH FOR
MARICOPA COUNTY EASTWARD...AND WE HAVE DROPPED THE WATCH FOR ALL
AREAS WEST OF MARICOPA COUNTY.

FOR THE REST OF THIS AFTERNOON...WE MAY SEE A FEW SHOWERS OR EVEN A
THUNDERSTORM REDEVELOP OVER PORTIONS OF SERN AZ AS CONVECTION SPILLS
OVER THE COASTAL RANGES...AND MOVES INLAND AND AHEAD OF THE
WEAKENING UPPER LOW ALONG THE FAR SERN CA COAST. WE DO NOT EXPECT
SIGNIFICANT PRECIP WITH ANY SHOWERS/STORMS THAT MOVE THROUGH SERN CA
HOWEVER...BUT SOME SPOTS COULD SEE AMOUNTS IN EXCESS OF ONE QUARTER
INCH.

BY EARLY THIS EVENING...THE MAIN FOCUS OF THIS STORM SYSTEM...THE
FRONTAL BAND AND ASSOCIATED RAIN/RAIN SHOWER SHIELD...WILL PUSH EAST
AND INTO FAR EASTERN AZ AND NEW MEXICO. AT THE SAME TIME THE LOW
ALONG THE SERN CA COAST WILL WEAKEN AND BE MOVED INLAND AS A KICKER
LOW DROPS SOUTH ALONG THE CENTRAL CA COAST. AS SUCH THE CHANCES FOR
MEASURABLE PRECIP WILL DROP OFF SIGNIFICANTLY THIS EVENING...INTO
THE CHANCE CATEGORY OVER THE CENTRAL DESERTS WITH LINGERING LIKELY
POPS ACROSS SRN GILA COUNTY. AFTER MIDNIGHT TONIGHT WE EXPECT MAINLY
SINGLE DIGIT POPS ACROSS THE SWRN AZ DESERTS AS WELL AS SERN CA.
MODELS ARE CONSISTENT IN CALLING FOR THIS KICKER LOW TO DROP
SOUTHEAST TOWARDS THE NRN BAJA CA COAST TONIGHT...THEN SLOWLY DRIFT
EAST AND PASS BY ARIZONA TO THE SOUTH TUESDAY INTO WEDNESDAY. AS THE
LOW PASSES BY...DYNAMICS OVER SRN AZ BECOME WEAK...BUT SIGNIFICANT
LOW/MID LEVEL MOISTURE REMAINS IN PLACE AND AS SUCH WE WILL CONTINUE
A SLIGHT CHANCE FOR INSTABILITY SHOWERS OVER SOUTH CENTRAL AZ
TUESDAY AND TUESDAY NIGHT. IN FACT...INSTABILITY LOOKS TO BE A BIT
BETTER ON TUESDAY WITH LI VALUES GOING WEAKLY NEGATIVE AND THUS WE
HAVE A SLIGHT CHANCE FOR THUNDER IN THE FORECAST ACROSS SOUTH
CENTRAL AZ ON TUESDAY. BY WEDNESDAY AFTERNOON THE ONLY THREAT FOR
PRECIP WILL BE OVER THE HIGHER TERRAIN EAST OF PHOENIX...AND SKIES
WILL BECOME MOSTLY SUNNY FROM PHOENIX WESTWARD INTO SERN CA. TEMPS
TUESDAY AND WEDNESDAY WILLS STEADILY WARM BUT WILL REMAIN BELOW
SEASONAL NORMALS.

ONE ISSUE WE WILL CONTEND WITH TONIGHT WILL BE FOG POTENTIAL ACROSS
SOUTH CENTRAL ARIZONA. MANY LOCATIONS WILL SEE AT LEAST MODERATE
RAINFALL TOTALS TODAY...AND HUMIDITY LEVELS WILL REMAIN HIGH
OVERNIGHT. HOWEVER...WE EXPECT LINGERING LOW/MID CLOUD DECKS TONIGHT
INTO TUESDAY...REDUCING RADITIONAL COOLING POTENTIAL. ALSO...
FORECAST SOUNDINGS ARE NOT CLASSICAL FOG SOUNDINGS. WINDS WILL BE
LIGHT BUT SHOULD NOT BE CALM FOR EXTENDED PERIODS. THUS...THERE MAY
BE PATCHY FOG WITH VISIBILITY DOWN BELOW 5 MILES AT TIMES BUT WE DO
NOT EXPECT SIGNIFICANT DENSE FOG. AS A COMPROMISE WE ADDED PATCHY
FOG TO OUR FORECAST ZONES EAST OF THE LOWER CO RIVER TONIGHT.

FOR THURSDAY...A DRYING AND SUBSIDENT NORTHERLY FLOW ALOFT WILL SET
UP ACROSS THE AREA AS HIGH PRESSURE ALOFT STARTS TO BUILD ALONG THE
CA COAST. THIS WILL LEADY TO SUNNY SKIES...AND CONTINUED WARMING
WITH HIGH TEMPS REACHING INTO THE LOW TO MID 70S...AND TOWARDS
SEASONAL NORMALS.

FRIDAY INTO THE WEEKEND...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A DECENT CHANCE FOR HIGHS IN THE 80S ACROSS THE LOWER
DESERTS BY THE WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
WIDESPREAD IMPACTS INCLUDING LOW CIGS...RAIN SHOWERS...LOWERED
VSBY...AND GUSTY WIND SHIFTS WILL BE COMMON ACROSS CNTRL ARIZONA
TERMINALS THROUGH THIS AFTERNOON. CIGS HAVE ALREADY STARTED LOWERING
BLO 6K FT WITH MTN OBSCURATION PREVAILING THROUGH THE DAY.
CONFIDENCE IS ONLY MODEST IN TIMING THE HEAVIEST SQUALLS INTO
KPHX...THOUGH MOST HIGH RESOLUTION MODELS SUGGEST A COUPLE HOURS
AROUND 18Z WITH PREVAILING MVFR CONDITIONS ALONG WITH A DISTINCT
WIND SHIFT. SOME BRIEF PERIODS OF IFR MAY ALSO BE POSSIBLE IN THE
HEAVIEST SHOWERS...THOUGH CONFIDENCE AND TEMPORAL DURATION TOO LOW
TO MENTION IN THIS TAF PACKAGE. CONFIDENCE IS VERY LOW BEYOND
00Z...AND SOME ADDITIONAL SCT SHRA AND CIGS FALLING BACK BLO 6K FT
MAY BE POSSIBLE.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
PREVAILING RAIN WILL MOVE EAST OF TERMINAL SITES BY 15Z...HOWEVER
LINGER LOW LEVEL MOISTURE HAS ALLOWED PATCHY MVFR TO LIFR CIGS TO
DEVELOP. NOT A LOT OF CONFIDENCE IN HOW LONG THESE LOWER CATEGORIES
WILL PERSIST...THOUGH MODELS SUGGEST ONLY A BRIEF TIME. WITH THE
UPPER LEVEL SYSTEM MOVING THROUGH SOUTHEAST CALIFORNIA THIS
AFTERNOON...CONFIDENCE IS BETTER THAN GUSTY WEST WINDS WILL DEVELOP
WITH SOME SHRA REDEVELOPMENT. CONDITIONS WILL IMPROVE QUICKLY AFTER
SUNSET.


AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
STRONG HIGH PRESSURE AND MUCH DRIER CONDITIONS WILL MOVE BACK INTO
THE DISTRICT DURING THE LATTER HALF OF THE WEEK. TEMPERATURES WILL
REBOUND BACK INTO A NORMAL TO SLIGHTLY ABOVE NORMAL RANGE...WHILE
AFTERNOON HUMIDITY LEVELS RETURN INTO A 15 TO 25 PERCENT RANGE.
OVERNIGHT RECOVERY WILL BE GOOD. PERIODS OF GUSTY NORTH WINDS DOWN
THE COLORADO RIVER VALLEY WILL BE LIKELY WEDNESDAY AFTERNOON...WHILE
OCCASIONAL PERIODS OF STRONGER EASTERLY WINDS OVER RIDGE TOPS OF
CENTRAL ARIZONA MAY BE COMMON LATE IN THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH THROUGH 8 PM TODAY AZZ022>024.

CA...NONE.

&&

$$

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

DISCUSSION...CB/PERCHA
AVIATION...MO
FIRE WEATHER...MO













000
FXUS65 KPSR 021626
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
925 AM MST MON MAR 2 2015

...POTENTIAL FOR HEAVY RAIN AFFECTING THE SOUTHWEST AND SOUTH
CENTRAL AZ DESERTS THROUGH LATE TODAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL EXPAND FROM SOUTHEAST CALIFORNIA INTO
ARIZONA TODAY...AND WILL SLOWLY SHIFT EASTWARD DURING THE COURSE OF
THE DAY. PERIODS OF MODERATE TO HEAVY RAIN ARE ANTICIPATED...
ESPECIALLY OVER THE HIGHER TERRAIN AND FOOTHILL LOCATIONS OF SOUTH
CENTRAL ARIZONA. THERE WILL ALSO BE A SLIGHT CHANCE OF THUNDERSTORMS
AS WELL...MAINLY DURING THE AFTERNOON AND EARLY EVENING HOURS.
COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS SYSTEM WITH BELOW
NORMAL READINGS EXPECTED FROM TODAY THROUGH MID WEEK. A RETURN TO
ABOVE NORMAL TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
A WET PACIFIC LOW PRESSURE SYSTEM CONTINUED TO BRING WIDESPREAD RAIN
AND RAIN SHOWERS TO THE DESERT SOUTHWEST THIS MORNING...ESPECIALLY
IN THE VICINITY OF THE ASSOCIATED COLD FRONT WHICH WAS PUSHING EACH
ACROSS THE CENTRAL DESERTS AS OF 8 AM. MAIN UPPER LOW CENTER WAS
SPINNING ALONG OR JUST OFF THE FAR SERN CA COAST THIS MORNING...AND
THERE WERE A COUPLE LIGHTNING STRIKES NOTED JUST OFFSHORE UNDER THE
UPPER COLD POOL. WIDESPREAD RAIN/RAIN SHOWERS WERE PRESENT ON RADAR
AT 8 AM...MAINLY EAST OF THE LOWER CO RIVER VALLEY OVER EASTERN YUMA
COUNTY AND WEST/CENTRAL MARICOPA COUNTY. AS THE FRONT MOVES EAST
ACROSS THE CENTRAL DESERTS THIS MORNING...RAIN CHANCES WILL APPROACH
100 PERCENT ACROSS MUCH OF THE GREATER PHOENIX AREA AND BY AFTERNOON
MOST OF SOUTH CENTRAL AZ WILL SEE RAIN TOTALS IN EXCESS OF ONE
QUARTER INCH. HIGHER RAINFALL TOTALS ARE LIKELY IN THE
FOOTHILL/HIGHER TERRAIN AREAS TO THE NORTH AND EAST OF CENTRAL
PHOENIX...WITH PEAK TOTALS RANGING FROM 0.75 INCHES TO SLIGHTLY OVER
ONE INCH. THIS SYSTEM LOOKS TO BE RATHER DYNAMIC...AIDED BY A 140KT
UPPER JET MOVING NORTHEASTWARD ACROSS CENTRAL AZ THIS
AFTERNOON...PUTTING MUCH OF SOUTH CENTRAL AZ UNDER THE FAVORED
RIGHT-REAR QUADRANT FOR ENHANCED LIFT. RH/OMEGA CROSS SECTIONS SHOW
DEEP UPWARD MOTION COMBINED WITH NEAR SATURATED CONDITIONS...AND
THUS WE HAVE NEARLY 100 PERCENT CHANCES FOR RAIN OVER THE DESERTS
TODAY. OF COURSE...WITH THE SHOWERS AND CLOUDS...HIGH TEMPS WILL
FALL INTO UPPER 50S TO LOW 60S THIS AFTERNOON OVER THE LOWER
DESERTS...READINGS THAT ARE OVER 10 DEGREES BELOW SEASONAL NORMALS.

BASED ON RADAR AND SATELLITE TRENDS...THREAT FOR SIGNIFICANT AREAL
FLOODING WEST OF THE LOWER CO RIVER IS ALMOST OVER AND THE AREAL
FLOOD WATCH WILL NO LONGER BE NEEDED IN THAT AREA. OTHERWISE WE WILL
KEEP THE AREAL FLOOD WATCH GOING THRU AT LEAST 5 PM FOR THE
CENTRAL/SOUTH CENTRAL ZONES. ALTHOUGH INSTABILITY IS NOT EXCESSIVE
TODAY...WITH LIFTED INDICES NEAR ZERO AND CAPE VALUES MOSTLY LESS
THAN 200 J/KG...SHOULD A STORM FORM THE STRONG DYNAMICS WILL LIKELY
INCREASE THE STORM INTENSITY AND ASSOCIATED RAINFALL. THUS...THREAT
FOR AREAL FLOODING IS STILL THERE AND THE WATCH WILL CONTINUE.

.PREVIOUS DISCUSSION...

TODAY AND TONIGHT...
THE WELL-ADVERTISED UPPER-LEVEL LOW CENTER...THAT HAS BEEN DROPPING
SOUTHWARD ALONG THE WEST COAST OVER THE LAST FEW DAYS...IS FINALLY
BEGINNING TO MOVE OFF TO THE EAST...INTO SOUTHERN CA THIS MORNING AS
THE LONG-AWAITED UPSTREAM KICKER...MOVES SOUTHWARD ACROSS NORTHERN
CA TOWARDS THIS LOW CENTER. THIS SYSTEM...WHICH BROUGHT RAINFALL
AMOUNTS RANGING FROM 0.25 INCH TO JUST OVER 1.00 INCH TO MUCH OF SE
CA YESTERDAY AND LAST NIGHT...WHICH WAS FORECAST WELL BY THE GFS
MODEL OUTPUT...IS EXPECTED TO MOVE INTO WESTERN ARIZONA THIS
MORNING...THEN ACROSS SOUTH-CENTRAL ARIZONA THIS AFTERNOON/EVENING.
NOW THAT THE MAIN UPPER LOW IS FINALLY SHIFTING TO THE EAST...THE
BAROCLINIC LEAF AND ASSOCIATED AREA OF RAINFALL IS ALSO MOVING INTO
EXTREME WESTERN ARIZONA AS OF THIS HOUR...BRINGING LIGHT TO MODERATE
RAINFALL TO PARTS OF YUMA AND LA PAZ COUNTY. THE LATEST GFS AND HRRR
HI-RES MODELS ARE NOW IN GOOD AGREEMENT ON THE TIMING OF THIS SYSTEM
AS IT CONTINUES TO MOVE EASTWARD ACROSS AZ TODAY...WITH BOTH OF THEM
BRINGING RAINFALL TO THE GREATER PHX AREA AROUND DAYBREAK/DURING THE
MORNING COMMUTE...THEN INTO THE EASTERNMOST PORTION OF OUR CWA
(SOUTHERN GILA COUNTY) BY EARLY AFTERNOON.

ALTHOUGH THIS HAS TURNED INTO A FAIRLY PROGRESSIVE SYSTEM (AFTER A
DELAYED ARRIVAL)...IT STILL LOOKS LIKE A FAIRLY ROBUST SYSTEM...AND
IT IS STILL EXPECTED TO BRING LOCALLY HEAVY RAIN TO SOUTH-CENTRAL
ARIZONA TODAY...ESPECIALLY OVER THE HIGHER TERRAIN NORTH AND EAST OF
PHOENIX. THIS IS DUE TO THE FACT THAT A PLUME OF VERY MOIST
AIR...WITH PWATS AROUND ONE INCH IS EXPECTED TO STREAM NORTH OVER
THE REGION TODAY ALONG AND JUST AHEAD OF THE MAIN SURFACE
FRONT/BAROCLINIC ZONE. THIS DEEP MOISTURE...COMBINED WITH GOOD
BAROCLINICITY...STRONG LOW-LEVEL UPSLOPE SOUTHERLY FLOW (850MB WINDS
IN THE 30-40KT RANGE)...AND INFLUENCE FROM THE RIGHT-ENTRANCE REGION
OF THE JET IS EXPECTED TO PRODUCE A RATHER SOLID BAND OF
MODERATE-HEAVY RAINFALL DURING ITS PASSAGE ACROSS SOUTH-CENTRAL
ARIZONA. ALSO...EVEN THOUGH THERE IS NOW A WHOLE LOT OF CAPE IN THE
FORECAST SOUNDINGS (A COUPLE HUNDRED JOULES/KG AT MOST)...THERE
APPEARS TO BE ENOUGH LIFT TO TRIGGER A FEW EMBEDDED THUNDERSTORMS
THIS AFTERNOON AS THE FRONT MOVES THROUGH. THE COMBINATION OF THE
GENERAL RAINFALL...RANGING FROM AROUND 1/2 INCH OVER WESTERN
MARICOPA COUNTY TO AS MUCH AS 2.00 INCHES IN THE MOST FAVORED
LOCATIONS OVER EXTREME NORTH AND NORTHEAST MARICOPA COUNTY...WITH
THESE HEAVIER SHOWERS...WILL LIKELY PRODUCE AT LEAST SOME LOCAL
FLOODING PROBLEMS IN OUR WASHES...HIGHWAY DIPS...AND LOW-LYING
AREAS. THERE COULD ALSO BE SOME RISES IN SOME OF OUR SMALLER CREEKS
AND STREAMS...ESPECIALLY OVER THE HIGHER TERRAIN. SNOWFALL...IF
ANY...IS STILL EXPECTED TO BE CONFINED TO OUR HIGHEST PEAKS...WHERE
A DUSTING TO PERHAPS AN INCH COULD FALL BEFORE THE PRECIP ENDS THIS
EVENING. ON THE OTHER HAND...MUCH GREATER SNOWFALL AMOUNTS ARE
EXPECTED FURTHER NORTH AND EAST...FROM THE FLAGSTAFF AREA EAST
ACROSS THE RIM COUNTY INTO THE WHITE MTNS.

IT NOW APPEARS THAT THE RAINFALL SHOULD DIMINISH RATHER RAPIDLY THIS
EVENING FROM WEST TO EAST AS THE MAIN UPPER TROF MOVES OFF TO THE
EAST AND THE LOW-LEVEL SOUTHERLY JET RAPIDLY BREAKS DOWN AND SHIFTS
TO A MUCH LIGHTER WESTERLY FLOW...WITH JUST A FEW LEFT-OVER
SPRINKLES OR LIGHT SHOWERS REMAINING BY LATE TONIGHT...MAINLY OVER
SOUTHERN GILA COUNTY. TEMPERATURES TODAY ARE EXPECTED TO BE MUCH
COOLER THAN WHAT WE SAW ON SUNDAY...WITH MANY LOWER DESERT LOCATIONS
ACROSS SOUTH-CENTRAL ARIZONA STAYING DOWN IN THE 50S THROUGH MUCH OF
THE DAY. LOWS TONIGHT ARE EXPECTED TO FALL INTO THE 40S AT MOST
LOWER DESERT LOCATIONS...WHICH IS NOW A FEW DEGREES BELOW NORMAL FOR
THIS TIME OF YEAR.

TUESDAY THROUGH THURSDAY...
A MUCH DRIER WEATHER REGIME IS EXPECTED AS NORTHWESTERLY FLOW ALOFT
BECOMES ESTABLISHED ACROSS THE REGION...WITH JUST A FEW SHOWERS
POSSIBLE FROM TIME-TO-TIME OVER THE HIGHER TERRAIN EAST OF
PHOENIX...AS WEAK SHORTWAVES EMBEDDED IN THIS NW FLOW MOVE ACROSS
EXTREME EASTERN AZ. TEMPERATURES ARE EXPECTED TO MAKE A SLOW REBOUND
AS 500MB HEIGHTS RISE...WITH HIGHS RETURNING TO NEAR-NORMAL VALUES
BY THURSDAY.

FRIDAY INTO NEXT WEEKEND...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A DECENT CHANCE FOR HIGHS IN THE 80S ACROSS THE LOWER
DESERTS BY NEXT WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
WIDESPREAD IMPACTS INCLUDING LOW CIGS...RAIN SHOWERS...LOWERED
VSBY...AND GUSTY WIND SHIFTS WILL BE COMMON ACROSS CNTRL ARIZONA
TERMINALS THROUGH THIS AFTERNOON. CIGS HAVE ALREADY STARTED LOWERING
BLO 6K FT WITH MTN OBSCURATION PREVAILING THROUGH THE DAY.
CONFIDENCE IS ONLY MODEST IN TIMING THE HEAVIEST SQUALLS INTO
KPHX...THOUGH MOST HIGH RESOLUTION MODELS SUGGEST A COUPLE HOURS
AROUND 18Z WITH PREVAILING MVFR CONDITIONS ALONG WITH A DISTINCT
WIND SHIFT. SOME BRIEF PERIODS OF IFR MAY ALSO BE POSSIBLE IN THE
HEAVIEST SHOWERS...THOUGH CONFIDENCE AND TEMPORAL DURATION TOO LOW
TO MENTION IN THIS TAF PACKAGE. CONFIDENCE IS VERY LOW BEYOND
00Z...AND SOME ADDITIONAL SCT SHRA AND CIGS FALLING BACK BLO 6K FT
MAY BE POSSIBLE.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
PREVAILING RAIN WILL MOVE EAST OF TERMINAL SITES BY 15Z...HOWEVER
LINGER LOW LEVEL MOISTURE HAS ALLOWED PATCHY MVFR TO LIFR CIGS TO
DEVELOP. NOT A LOT OF CONFIDENCE IN HOW LONG THESE LOWER CATEGORIES
WILL PERSIST...THOUGH MODELS SUGGEST ONLY A BRIEF TIME. WITH THE
UPPER LEVEL SYSTEM MOVING THROUGH SOUTHEAST CALIFORNIA THIS
AFTERNOON...CONFIDENCE IS BETTER THAN GUSTY WEST WINDS WILL DEVELOP
WITH SOME SHRA REDEVELOPMENT. CONDITIONS WILL IMPROVE QUICKLY AFTER
SUNSET.


AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
STRONG HIGH PRESSURE AND MUCH DRIER CONDITIONS WILL MOVE BACK INTO
THE DISTRICT DURING THE LATTER HALF OF THE WEEK. TEMPERATURES WILL
REBOUND BACK INTO A NORMAL TO SLIGHTLY ABOVE NORMAL RANGE...WHILE
AFTERNOON HUMIDITY LEVELS RETURN INTO A 15 TO 25 PERCENT RANGE.
OVERNIGHT RECOVERY WILL BE GOOD. PERIODS OF GUSTY NORTH WINDS DOWN
THE COLORADO RIVER VALLEY WILL BE LIKELY WEDNESDAY AFTERNOON...WHILE
OCCASIONAL PERIODS OF STRONGER EASTERLY WINDS OVER RIDGE TOPS OF
CENTRAL ARIZONA MAY BE COMMON LATE IN THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH THROUGH 5 PM TODAY AZZ020>021.
     FLOOD WATCH THROUGH 8 PM TODAY AZZ022>024.

CA...FLOOD WATCH UNTIL 12 PM TODAY CAZ031>033.

&&

$$

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

DISCUSSION...CB
PREVIOUS DISCUSSION...PERCHA
AVIATION...MO
FIRE WEATHER...MO










000
FXUS65 KPSR 021626
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
925 AM MST MON MAR 2 2015

...POTENTIAL FOR HEAVY RAIN AFFECTING THE SOUTHWEST AND SOUTH
CENTRAL AZ DESERTS THROUGH LATE TODAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL EXPAND FROM SOUTHEAST CALIFORNIA INTO
ARIZONA TODAY...AND WILL SLOWLY SHIFT EASTWARD DURING THE COURSE OF
THE DAY. PERIODS OF MODERATE TO HEAVY RAIN ARE ANTICIPATED...
ESPECIALLY OVER THE HIGHER TERRAIN AND FOOTHILL LOCATIONS OF SOUTH
CENTRAL ARIZONA. THERE WILL ALSO BE A SLIGHT CHANCE OF THUNDERSTORMS
AS WELL...MAINLY DURING THE AFTERNOON AND EARLY EVENING HOURS.
COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS SYSTEM WITH BELOW
NORMAL READINGS EXPECTED FROM TODAY THROUGH MID WEEK. A RETURN TO
ABOVE NORMAL TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
A WET PACIFIC LOW PRESSURE SYSTEM CONTINUED TO BRING WIDESPREAD RAIN
AND RAIN SHOWERS TO THE DESERT SOUTHWEST THIS MORNING...ESPECIALLY
IN THE VICINITY OF THE ASSOCIATED COLD FRONT WHICH WAS PUSHING EACH
ACROSS THE CENTRAL DESERTS AS OF 8 AM. MAIN UPPER LOW CENTER WAS
SPINNING ALONG OR JUST OFF THE FAR SERN CA COAST THIS MORNING...AND
THERE WERE A COUPLE LIGHTNING STRIKES NOTED JUST OFFSHORE UNDER THE
UPPER COLD POOL. WIDESPREAD RAIN/RAIN SHOWERS WERE PRESENT ON RADAR
AT 8 AM...MAINLY EAST OF THE LOWER CO RIVER VALLEY OVER EASTERN YUMA
COUNTY AND WEST/CENTRAL MARICOPA COUNTY. AS THE FRONT MOVES EAST
ACROSS THE CENTRAL DESERTS THIS MORNING...RAIN CHANCES WILL APPROACH
100 PERCENT ACROSS MUCH OF THE GREATER PHOENIX AREA AND BY AFTERNOON
MOST OF SOUTH CENTRAL AZ WILL SEE RAIN TOTALS IN EXCESS OF ONE
QUARTER INCH. HIGHER RAINFALL TOTALS ARE LIKELY IN THE
FOOTHILL/HIGHER TERRAIN AREAS TO THE NORTH AND EAST OF CENTRAL
PHOENIX...WITH PEAK TOTALS RANGING FROM 0.75 INCHES TO SLIGHTLY OVER
ONE INCH. THIS SYSTEM LOOKS TO BE RATHER DYNAMIC...AIDED BY A 140KT
UPPER JET MOVING NORTHEASTWARD ACROSS CENTRAL AZ THIS
AFTERNOON...PUTTING MUCH OF SOUTH CENTRAL AZ UNDER THE FAVORED
RIGHT-REAR QUADRANT FOR ENHANCED LIFT. RH/OMEGA CROSS SECTIONS SHOW
DEEP UPWARD MOTION COMBINED WITH NEAR SATURATED CONDITIONS...AND
THUS WE HAVE NEARLY 100 PERCENT CHANCES FOR RAIN OVER THE DESERTS
TODAY. OF COURSE...WITH THE SHOWERS AND CLOUDS...HIGH TEMPS WILL
FALL INTO UPPER 50S TO LOW 60S THIS AFTERNOON OVER THE LOWER
DESERTS...READINGS THAT ARE OVER 10 DEGREES BELOW SEASONAL NORMALS.

BASED ON RADAR AND SATELLITE TRENDS...THREAT FOR SIGNIFICANT AREAL
FLOODING WEST OF THE LOWER CO RIVER IS ALMOST OVER AND THE AREAL
FLOOD WATCH WILL NO LONGER BE NEEDED IN THAT AREA. OTHERWISE WE WILL
KEEP THE AREAL FLOOD WATCH GOING THRU AT LEAST 5 PM FOR THE
CENTRAL/SOUTH CENTRAL ZONES. ALTHOUGH INSTABILITY IS NOT EXCESSIVE
TODAY...WITH LIFTED INDICES NEAR ZERO AND CAPE VALUES MOSTLY LESS
THAN 200 J/KG...SHOULD A STORM FORM THE STRONG DYNAMICS WILL LIKELY
INCREASE THE STORM INTENSITY AND ASSOCIATED RAINFALL. THUS...THREAT
FOR AREAL FLOODING IS STILL THERE AND THE WATCH WILL CONTINUE.

.PREVIOUS DISCUSSION...

TODAY AND TONIGHT...
THE WELL-ADVERTISED UPPER-LEVEL LOW CENTER...THAT HAS BEEN DROPPING
SOUTHWARD ALONG THE WEST COAST OVER THE LAST FEW DAYS...IS FINALLY
BEGINNING TO MOVE OFF TO THE EAST...INTO SOUTHERN CA THIS MORNING AS
THE LONG-AWAITED UPSTREAM KICKER...MOVES SOUTHWARD ACROSS NORTHERN
CA TOWARDS THIS LOW CENTER. THIS SYSTEM...WHICH BROUGHT RAINFALL
AMOUNTS RANGING FROM 0.25 INCH TO JUST OVER 1.00 INCH TO MUCH OF SE
CA YESTERDAY AND LAST NIGHT...WHICH WAS FORECAST WELL BY THE GFS
MODEL OUTPUT...IS EXPECTED TO MOVE INTO WESTERN ARIZONA THIS
MORNING...THEN ACROSS SOUTH-CENTRAL ARIZONA THIS AFTERNOON/EVENING.
NOW THAT THE MAIN UPPER LOW IS FINALLY SHIFTING TO THE EAST...THE
BAROCLINIC LEAF AND ASSOCIATED AREA OF RAINFALL IS ALSO MOVING INTO
EXTREME WESTERN ARIZONA AS OF THIS HOUR...BRINGING LIGHT TO MODERATE
RAINFALL TO PARTS OF YUMA AND LA PAZ COUNTY. THE LATEST GFS AND HRRR
HI-RES MODELS ARE NOW IN GOOD AGREEMENT ON THE TIMING OF THIS SYSTEM
AS IT CONTINUES TO MOVE EASTWARD ACROSS AZ TODAY...WITH BOTH OF THEM
BRINGING RAINFALL TO THE GREATER PHX AREA AROUND DAYBREAK/DURING THE
MORNING COMMUTE...THEN INTO THE EASTERNMOST PORTION OF OUR CWA
(SOUTHERN GILA COUNTY) BY EARLY AFTERNOON.

ALTHOUGH THIS HAS TURNED INTO A FAIRLY PROGRESSIVE SYSTEM (AFTER A
DELAYED ARRIVAL)...IT STILL LOOKS LIKE A FAIRLY ROBUST SYSTEM...AND
IT IS STILL EXPECTED TO BRING LOCALLY HEAVY RAIN TO SOUTH-CENTRAL
ARIZONA TODAY...ESPECIALLY OVER THE HIGHER TERRAIN NORTH AND EAST OF
PHOENIX. THIS IS DUE TO THE FACT THAT A PLUME OF VERY MOIST
AIR...WITH PWATS AROUND ONE INCH IS EXPECTED TO STREAM NORTH OVER
THE REGION TODAY ALONG AND JUST AHEAD OF THE MAIN SURFACE
FRONT/BAROCLINIC ZONE. THIS DEEP MOISTURE...COMBINED WITH GOOD
BAROCLINICITY...STRONG LOW-LEVEL UPSLOPE SOUTHERLY FLOW (850MB WINDS
IN THE 30-40KT RANGE)...AND INFLUENCE FROM THE RIGHT-ENTRANCE REGION
OF THE JET IS EXPECTED TO PRODUCE A RATHER SOLID BAND OF
MODERATE-HEAVY RAINFALL DURING ITS PASSAGE ACROSS SOUTH-CENTRAL
ARIZONA. ALSO...EVEN THOUGH THERE IS NOW A WHOLE LOT OF CAPE IN THE
FORECAST SOUNDINGS (A COUPLE HUNDRED JOULES/KG AT MOST)...THERE
APPEARS TO BE ENOUGH LIFT TO TRIGGER A FEW EMBEDDED THUNDERSTORMS
THIS AFTERNOON AS THE FRONT MOVES THROUGH. THE COMBINATION OF THE
GENERAL RAINFALL...RANGING FROM AROUND 1/2 INCH OVER WESTERN
MARICOPA COUNTY TO AS MUCH AS 2.00 INCHES IN THE MOST FAVORED
LOCATIONS OVER EXTREME NORTH AND NORTHEAST MARICOPA COUNTY...WITH
THESE HEAVIER SHOWERS...WILL LIKELY PRODUCE AT LEAST SOME LOCAL
FLOODING PROBLEMS IN OUR WASHES...HIGHWAY DIPS...AND LOW-LYING
AREAS. THERE COULD ALSO BE SOME RISES IN SOME OF OUR SMALLER CREEKS
AND STREAMS...ESPECIALLY OVER THE HIGHER TERRAIN. SNOWFALL...IF
ANY...IS STILL EXPECTED TO BE CONFINED TO OUR HIGHEST PEAKS...WHERE
A DUSTING TO PERHAPS AN INCH COULD FALL BEFORE THE PRECIP ENDS THIS
EVENING. ON THE OTHER HAND...MUCH GREATER SNOWFALL AMOUNTS ARE
EXPECTED FURTHER NORTH AND EAST...FROM THE FLAGSTAFF AREA EAST
ACROSS THE RIM COUNTY INTO THE WHITE MTNS.

IT NOW APPEARS THAT THE RAINFALL SHOULD DIMINISH RATHER RAPIDLY THIS
EVENING FROM WEST TO EAST AS THE MAIN UPPER TROF MOVES OFF TO THE
EAST AND THE LOW-LEVEL SOUTHERLY JET RAPIDLY BREAKS DOWN AND SHIFTS
TO A MUCH LIGHTER WESTERLY FLOW...WITH JUST A FEW LEFT-OVER
SPRINKLES OR LIGHT SHOWERS REMAINING BY LATE TONIGHT...MAINLY OVER
SOUTHERN GILA COUNTY. TEMPERATURES TODAY ARE EXPECTED TO BE MUCH
COOLER THAN WHAT WE SAW ON SUNDAY...WITH MANY LOWER DESERT LOCATIONS
ACROSS SOUTH-CENTRAL ARIZONA STAYING DOWN IN THE 50S THROUGH MUCH OF
THE DAY. LOWS TONIGHT ARE EXPECTED TO FALL INTO THE 40S AT MOST
LOWER DESERT LOCATIONS...WHICH IS NOW A FEW DEGREES BELOW NORMAL FOR
THIS TIME OF YEAR.

TUESDAY THROUGH THURSDAY...
A MUCH DRIER WEATHER REGIME IS EXPECTED AS NORTHWESTERLY FLOW ALOFT
BECOMES ESTABLISHED ACROSS THE REGION...WITH JUST A FEW SHOWERS
POSSIBLE FROM TIME-TO-TIME OVER THE HIGHER TERRAIN EAST OF
PHOENIX...AS WEAK SHORTWAVES EMBEDDED IN THIS NW FLOW MOVE ACROSS
EXTREME EASTERN AZ. TEMPERATURES ARE EXPECTED TO MAKE A SLOW REBOUND
AS 500MB HEIGHTS RISE...WITH HIGHS RETURNING TO NEAR-NORMAL VALUES
BY THURSDAY.

FRIDAY INTO NEXT WEEKEND...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A DECENT CHANCE FOR HIGHS IN THE 80S ACROSS THE LOWER
DESERTS BY NEXT WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
WIDESPREAD IMPACTS INCLUDING LOW CIGS...RAIN SHOWERS...LOWERED
VSBY...AND GUSTY WIND SHIFTS WILL BE COMMON ACROSS CNTRL ARIZONA
TERMINALS THROUGH THIS AFTERNOON. CIGS HAVE ALREADY STARTED LOWERING
BLO 6K FT WITH MTN OBSCURATION PREVAILING THROUGH THE DAY.
CONFIDENCE IS ONLY MODEST IN TIMING THE HEAVIEST SQUALLS INTO
KPHX...THOUGH MOST HIGH RESOLUTION MODELS SUGGEST A COUPLE HOURS
AROUND 18Z WITH PREVAILING MVFR CONDITIONS ALONG WITH A DISTINCT
WIND SHIFT. SOME BRIEF PERIODS OF IFR MAY ALSO BE POSSIBLE IN THE
HEAVIEST SHOWERS...THOUGH CONFIDENCE AND TEMPORAL DURATION TOO LOW
TO MENTION IN THIS TAF PACKAGE. CONFIDENCE IS VERY LOW BEYOND
00Z...AND SOME ADDITIONAL SCT SHRA AND CIGS FALLING BACK BLO 6K FT
MAY BE POSSIBLE.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
PREVAILING RAIN WILL MOVE EAST OF TERMINAL SITES BY 15Z...HOWEVER
LINGER LOW LEVEL MOISTURE HAS ALLOWED PATCHY MVFR TO LIFR CIGS TO
DEVELOP. NOT A LOT OF CONFIDENCE IN HOW LONG THESE LOWER CATEGORIES
WILL PERSIST...THOUGH MODELS SUGGEST ONLY A BRIEF TIME. WITH THE
UPPER LEVEL SYSTEM MOVING THROUGH SOUTHEAST CALIFORNIA THIS
AFTERNOON...CONFIDENCE IS BETTER THAN GUSTY WEST WINDS WILL DEVELOP
WITH SOME SHRA REDEVELOPMENT. CONDITIONS WILL IMPROVE QUICKLY AFTER
SUNSET.


AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
STRONG HIGH PRESSURE AND MUCH DRIER CONDITIONS WILL MOVE BACK INTO
THE DISTRICT DURING THE LATTER HALF OF THE WEEK. TEMPERATURES WILL
REBOUND BACK INTO A NORMAL TO SLIGHTLY ABOVE NORMAL RANGE...WHILE
AFTERNOON HUMIDITY LEVELS RETURN INTO A 15 TO 25 PERCENT RANGE.
OVERNIGHT RECOVERY WILL BE GOOD. PERIODS OF GUSTY NORTH WINDS DOWN
THE COLORADO RIVER VALLEY WILL BE LIKELY WEDNESDAY AFTERNOON...WHILE
OCCASIONAL PERIODS OF STRONGER EASTERLY WINDS OVER RIDGE TOPS OF
CENTRAL ARIZONA MAY BE COMMON LATE IN THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH THROUGH 5 PM TODAY AZZ020>021.
     FLOOD WATCH THROUGH 8 PM TODAY AZZ022>024.

CA...FLOOD WATCH UNTIL 12 PM TODAY CAZ031>033.

&&

$$

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

DISCUSSION...CB
PREVIOUS DISCUSSION...PERCHA
AVIATION...MO
FIRE WEATHER...MO











000
FXUS65 KPSR 021126
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
425 AM MST MON MAR 2 2015

...UPDATED AVIATION AND FIRE WEATHER...

...POTENTIAL FOR HEAVY RAIN AFFECTING THE SOUTHWEST AND SOUTH
CENTRAL AZ DESERTS THROUGH LATE TODAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL EXPAND FROM SOUTHEAST CALIFORNIA INTO
ARIZONA TODAY...AND WILL SLOWLY SHIFT EASTWARD DURING THE COURSE OF
THE DAY. PERIODS OF MODERATE TO HEAVY RAIN ARE
ANTICIPATED...ESPECIALLY OVER THE HIGHER TERRAIN AND FOOTHILL
LOCATIONS OF SOUTH CENTRAL ARIZONA. THERE WILL ALSO BE A SLIGHT
CHANCE OF THUNDERSTORMS AS WELL...MAINLY DURING THE AFTERNOON AND
EARLY EVENING HOURS. COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS
SYSTEM WITH BELOW NORMAL READINGS EXPECTED FROM TODAY THROUGH MID
WEEK. A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...

TODAY AND TONIGHT...

THE WELL-ADVERTISED UPPER-LEVEL LOW CENTER...THAT HAS BEEN DROPPING
SOUTHWARD ALONG THE WEST COAST OVER THE LAST FEW DAYS...IS FINALLY
BEGINNING TO MOVE OFF TO THE EAST...INTO SOUTHERN CA THIS MORNING AS
THE LONG-AWAITED UPSTREAM KICKER...MOVES SOUTHWARD ACROSS NORTHERN
CA TOWARDS THIS LOW CENTER. THIS SYSTEM...WHICH BROUGHT RAINFALL
AMOUNTS RANGING FROM 0.25 INCH TO JUST OVER 1.00 INCH TO MUCH OF SE
CA YESTERDAY AND LAST NIGHT...WHICH WAS FORECAST WELL BY THE GFS
MODEL OUTPUT...IS EXPECTED TO MOVE INTO WESTERN ARIZONA THIS
MORNING...THEN ACROSS SOUTH-CENTRAL ARIZONA THIS AFTERNOON/EVENING.
NOW THAT THE MAIN UPPER LOW IS FINALLY SHIFTING TO THE EAST...THE
BAROCLINIC LEAF AND ASSOCIATED AREA OF RAINFALL IS ALSO MOVING INTO
EXTREME WESTERN ARIZONA AS OF THIS HOUR...BRINGING LIGHT TO MODERATE
RAINFALL TO PARTS OF YUMA AND LA PAZ COUNTY. THE LATEST GFS AND HRRR
HI-RES MODELS ARE NOW IN GOOD AGREEMENT ON THE TIMING OF THIS SYSTEM
AS IT CONTINUES TO MOVE EASTWARD ACROSS AZ TODAY...WITH BOTH OF THEM
BRINGING RAINFALL TO THE GREATER PHX AREA AROUND DAYBREAK/DURING THE
MORNING COMMUTE...THEN INTO THE EASTERNMOST PORTION OF OUR CWA
(SOUTHERN GILA COUNTY) BY EARLY AFTERNOON.

ALTHOUGH THIS HAS TURNED INTO A FAIRLY PROGRESSIVE SYSTEM (AFTER A
DELAYED ARRIVAL)...IT STILL LOOKS LIKE A FAIRLY ROBUST SYSTEM...AND
IT IS STILL EXPECTED TO BRING LOCALLY HEAVY RAIN TO SOUTH-CENTRAL
ARIZONA TODAY...ESPECIALLY OVER THE HIGHER TERRAIN NORTH AND EAST OF
PHOENIX. THIS IS DUE TO THE FACT THAT A PLUME OF VERY MOIST
AIR...WITH PWATS AROUND ONE INCH IS EXPECTED TO STREAM NORTH OVER
THE REGION TODAY ALONG AND JUST AHEAD OF THE MAIN SURFACE
FRONT/BAROCLINIC ZONE. THIS DEEP MOISTURE...COMBINED WITH GOOD
BAROCLINICITY...STRONG LOW-LEVEL UPSLOPE SOUTHERLY FLOW (850MB WINDS
IN THE 30-40KT RANGE)...AND INFLUENCE FROM THE RIGHT-ENTRANCE REGION
OF THE JET IS EXPECTED TO PRODUCE A RATHER SOLID BAND OF
MODERATE-HEAVY RAINFALL DURING ITS PASSAGE ACROSS SOUTH-CENTRAL
ARIZONA. ALSO...EVEN THOUGH THERE IS NOW A WHOLE LOT OF CAPE IN THE
FORECAST SOUNDINGS (A COUPLE HUNDRED JOULES/KG AT MOST)...THERE
APPEARS TO BE ENOUGH LIFT TO TRIGGER A FEW EMBEDDED THUNDERSTORMS
THIS AFTERNOON AS THE FRONT MOVES THROUGH. THE COMBINATION OF THE
GENERAL RAINFALL...RANGING FROM AROUND 1/2 INCH OVER WESTERN
MARICOPA COUNTY TO AS MUCH AS 2.00 INCHES IN THE MOST FAVORED
LOCATIONS OVER EXTREME NORTH AND NORTHEAST MARICOPA COUNTY...WITH
THESE HEAVIER SHOWERS...WILL LIKELY PRODUCE AT LEAST SOME LOCAL
FLOODING PROBLEMS IN OUR WASHES...HIGHWAY DIPS...AND LOW-LYING
AREAS. THERE COULD ALSO BE SOME RISES IN SOME OF OUR SMALLER CREEKS
AND STREAMS...ESPECIALLY OVER THE HIGHER TERRAIN. SNOWFALL...IF
ANY...IS STILL EXPECTED TO BE CONFINED TO OUR HIGHEST PEAKS...WHERE
A DUSTING TO PERHAPS AN INCH COULD FALL BEFORE THE PRECIP ENDS THIS
EVENING. ON THE OTHER HAND...MUCH GREATER SNOWFALL AMOUNTS ARE
EXPECTED FURTHER NORTH AND EAST...FROM THE FLAGSTAFF AREA EAST
ACROSS THE RIM COUNTY INTO THE WHITE MTNS.

IT NOW APPEARS THAT THE RAINFALL SHOULD DIMINISH RATHER RAPIDLY THIS
EVENING FROM WEST TO EAST AS THE MAIN UPPER TROF MOVES OFF TO THE
EAST AND THE LOW-LEVEL SOUTHERLY JET RAPIDLY BREAKS DOWN AND SHIFTS
TO A MUCH LIGHTER WESTERLY FLOW...WITH JUST A FEW LEFT-OVER
SPRINKLES OR LIGHT SHOWERS REMAINING BY LATE TONIGHT...MAINLY OVER
SOUTHERN GILA COUNTY. TEMPERATURES TODAY ARE EXPECTED TO BE MUCH
COOLER THAN WHAT WE SAW ON SUNDAY...WITH MANY LOWER DESERT LOCATIONS
ACROSS SOUTH-CENTRAL ARIZONA STAYING DOWN IN THE 50S THROUGH MUCH OF
THE DAY. LOWS TONIGHT ARE EXPECTED TO FALL INTO THE 40S AT MOST
LOWER DESERT LOCATIONS...WHICH IS NOW A FEW DEGREES BELOW NORMAL FOR
THIS TIME OF YEAR.

TUESDAY THROUGH THURSDAY...
A MUCH DRIER WEATHER REGIME IS EXPECTED AS NORTHWESTERLY FLOW ALOFT
BECOMES ESTABLISHED ACROSS THE REGION...WITH JUST A FEW SHOWERS
POSSIBLE FROM TIME-TO-TIME OVER THE HIGHER TERRAIN EAST OF
PHOENIX...AS WEAK SHORTWAVES EMBEDDED IN THIS NW FLOW MOVE ACROSS
EXTREME EASTERN AZ. TEMPERATURES ARE EXPECTED TO MAKE A SLOW REBOUND
AS 500MB HEIGHTS RISE...WITH HIGHS RETURNING TO NEAR-NORMAL VALUES
BY THURSDAY.

FRIDAY INTO NEXT WEEKEND...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A DECENT CHANCE FOR HIGHS IN THE 80S ACROSS THE LOWER
DESERTS BY NEXT WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
WIDESPREAD IMPACTS INCLUDING LOW CIGS...RAIN SHOWERS...LOWERED
VSBY...AND GUSTY WIND SHIFTS WILL BE COMMON ACROSS CNTRL ARIZONA
TERMINALS THROUGH THIS AFTERNOON. CIGS HAVE ALREADY STARTED LOWERING
BLO 6K FT WITH MTN OBSCURATION PREVAILING THROUGH THE DAY.
CONFIDENCE IS ONLY MODEST IN TIMING THE HEAVIEST SQUALLS INTO
KPHX...THOUGH MOST HIGH RESOLUTION MODELS SUGGEST A COUPLE HOURS
AROUND 18Z WITH PREVAILING MVFR CONDITIONS ALONG WITH A DISTINCT
WIND SHIFT. SOME BRIEF PERIODS OF IFR MAY ALSO BE POSSIBLE IN THE
HEAVIEST SHOWERS...THOUGH CONFIDENCE AND TEMPORAL DURATION TOO LOW
TO MENTION IN THIS TAF PACKAGE. CONFIDENCE IS VERY LOW BEYOND
00Z...AND SOME ADDITIONAL SCT SHRA AND CIGS FALLING BACK BLO 6K FT
MAY BE POSSIBLE.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
PREVAILING RAIN WILL MOVE EAST OF TERMINAL SITES BY 15Z...HOWEVER
LINGER LOW LEVEL MOISTURE HAS ALLOWED PATCHY MVFR TO LIFR CIGS TO
DEVELOP. NOT A LOT OF CONFIDENCE IN HOW LONG THESE LOWER CATEGORIES
WILL PERSIST...THOUGH MODELS SUGGEST ONLY A BRIEF TIME. WITH THE
UPPER LEVEL SYSTEM MOVING THROUGH SOUTHEAST CALIFORNIA THIS
AFTERNOON...CONFIDENCE IS BETTER THAN GUSTY WEST WINDS WILL DEVELOP
WITH SOME SHRA REDEVELOPMENT. CONDITIONS WILL IMPROVE QUICKLY AFTER
SUNSET.


AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
STRONG HIGH PRESSURE AND MUCH DRIER CONDITIONS WILL MOVE BACK INTO
THE DISTRICT DURING THE LATTER HALF OF THE WEEK. TEMPERATURES WILL
REBOUND BACK INTO A NORMAL TO SLIGHTLY ABOVE NORMAL RANGE...WHILE
AFTERNOON HUMIDITY LEVELS RETURN INTO A 15 TO 25 PERCENT RANGE.
OVERNIGHT RECOVERY WILL BE GOOD. PERIODS OF GUSTY NORTH WINDS DOWN
THE COLORADO RIVER VALLEY WILL BE LIKELY WEDNESDAY AFTERNOON...WHILE
OCCASIONAL PERIODS OF STRONGER EASTERLY WINDS OVER RIDGE TOPS OF
CENTRAL ARIZONA MAY BE COMMON LATE IN THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ020>021.
     FLOOD WATCH FROM MIDNIGHT TONIGHT THROUGH 8 PM MONDAY
     AZZ022>024.

CA...FLOOD WATCH UNTIL 12 PM MONDAY CAZ031>033.

&&

$$

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

DISCUSSION...PERCHA
AVIATION...MO
FIRE WEATHER...MO








000
FXUS65 KPSR 021126
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
425 AM MST MON MAR 2 2015

...UPDATED AVIATION AND FIRE WEATHER...

...POTENTIAL FOR HEAVY RAIN AFFECTING THE SOUTHWEST AND SOUTH
CENTRAL AZ DESERTS THROUGH LATE TODAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL EXPAND FROM SOUTHEAST CALIFORNIA INTO
ARIZONA TODAY...AND WILL SLOWLY SHIFT EASTWARD DURING THE COURSE OF
THE DAY. PERIODS OF MODERATE TO HEAVY RAIN ARE
ANTICIPATED...ESPECIALLY OVER THE HIGHER TERRAIN AND FOOTHILL
LOCATIONS OF SOUTH CENTRAL ARIZONA. THERE WILL ALSO BE A SLIGHT
CHANCE OF THUNDERSTORMS AS WELL...MAINLY DURING THE AFTERNOON AND
EARLY EVENING HOURS. COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS
SYSTEM WITH BELOW NORMAL READINGS EXPECTED FROM TODAY THROUGH MID
WEEK. A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...

TODAY AND TONIGHT...

THE WELL-ADVERTISED UPPER-LEVEL LOW CENTER...THAT HAS BEEN DROPPING
SOUTHWARD ALONG THE WEST COAST OVER THE LAST FEW DAYS...IS FINALLY
BEGINNING TO MOVE OFF TO THE EAST...INTO SOUTHERN CA THIS MORNING AS
THE LONG-AWAITED UPSTREAM KICKER...MOVES SOUTHWARD ACROSS NORTHERN
CA TOWARDS THIS LOW CENTER. THIS SYSTEM...WHICH BROUGHT RAINFALL
AMOUNTS RANGING FROM 0.25 INCH TO JUST OVER 1.00 INCH TO MUCH OF SE
CA YESTERDAY AND LAST NIGHT...WHICH WAS FORECAST WELL BY THE GFS
MODEL OUTPUT...IS EXPECTED TO MOVE INTO WESTERN ARIZONA THIS
MORNING...THEN ACROSS SOUTH-CENTRAL ARIZONA THIS AFTERNOON/EVENING.
NOW THAT THE MAIN UPPER LOW IS FINALLY SHIFTING TO THE EAST...THE
BAROCLINIC LEAF AND ASSOCIATED AREA OF RAINFALL IS ALSO MOVING INTO
EXTREME WESTERN ARIZONA AS OF THIS HOUR...BRINGING LIGHT TO MODERATE
RAINFALL TO PARTS OF YUMA AND LA PAZ COUNTY. THE LATEST GFS AND HRRR
HI-RES MODELS ARE NOW IN GOOD AGREEMENT ON THE TIMING OF THIS SYSTEM
AS IT CONTINUES TO MOVE EASTWARD ACROSS AZ TODAY...WITH BOTH OF THEM
BRINGING RAINFALL TO THE GREATER PHX AREA AROUND DAYBREAK/DURING THE
MORNING COMMUTE...THEN INTO THE EASTERNMOST PORTION OF OUR CWA
(SOUTHERN GILA COUNTY) BY EARLY AFTERNOON.

ALTHOUGH THIS HAS TURNED INTO A FAIRLY PROGRESSIVE SYSTEM (AFTER A
DELAYED ARRIVAL)...IT STILL LOOKS LIKE A FAIRLY ROBUST SYSTEM...AND
IT IS STILL EXPECTED TO BRING LOCALLY HEAVY RAIN TO SOUTH-CENTRAL
ARIZONA TODAY...ESPECIALLY OVER THE HIGHER TERRAIN NORTH AND EAST OF
PHOENIX. THIS IS DUE TO THE FACT THAT A PLUME OF VERY MOIST
AIR...WITH PWATS AROUND ONE INCH IS EXPECTED TO STREAM NORTH OVER
THE REGION TODAY ALONG AND JUST AHEAD OF THE MAIN SURFACE
FRONT/BAROCLINIC ZONE. THIS DEEP MOISTURE...COMBINED WITH GOOD
BAROCLINICITY...STRONG LOW-LEVEL UPSLOPE SOUTHERLY FLOW (850MB WINDS
IN THE 30-40KT RANGE)...AND INFLUENCE FROM THE RIGHT-ENTRANCE REGION
OF THE JET IS EXPECTED TO PRODUCE A RATHER SOLID BAND OF
MODERATE-HEAVY RAINFALL DURING ITS PASSAGE ACROSS SOUTH-CENTRAL
ARIZONA. ALSO...EVEN THOUGH THERE IS NOW A WHOLE LOT OF CAPE IN THE
FORECAST SOUNDINGS (A COUPLE HUNDRED JOULES/KG AT MOST)...THERE
APPEARS TO BE ENOUGH LIFT TO TRIGGER A FEW EMBEDDED THUNDERSTORMS
THIS AFTERNOON AS THE FRONT MOVES THROUGH. THE COMBINATION OF THE
GENERAL RAINFALL...RANGING FROM AROUND 1/2 INCH OVER WESTERN
MARICOPA COUNTY TO AS MUCH AS 2.00 INCHES IN THE MOST FAVORED
LOCATIONS OVER EXTREME NORTH AND NORTHEAST MARICOPA COUNTY...WITH
THESE HEAVIER SHOWERS...WILL LIKELY PRODUCE AT LEAST SOME LOCAL
FLOODING PROBLEMS IN OUR WASHES...HIGHWAY DIPS...AND LOW-LYING
AREAS. THERE COULD ALSO BE SOME RISES IN SOME OF OUR SMALLER CREEKS
AND STREAMS...ESPECIALLY OVER THE HIGHER TERRAIN. SNOWFALL...IF
ANY...IS STILL EXPECTED TO BE CONFINED TO OUR HIGHEST PEAKS...WHERE
A DUSTING TO PERHAPS AN INCH COULD FALL BEFORE THE PRECIP ENDS THIS
EVENING. ON THE OTHER HAND...MUCH GREATER SNOWFALL AMOUNTS ARE
EXPECTED FURTHER NORTH AND EAST...FROM THE FLAGSTAFF AREA EAST
ACROSS THE RIM COUNTY INTO THE WHITE MTNS.

IT NOW APPEARS THAT THE RAINFALL SHOULD DIMINISH RATHER RAPIDLY THIS
EVENING FROM WEST TO EAST AS THE MAIN UPPER TROF MOVES OFF TO THE
EAST AND THE LOW-LEVEL SOUTHERLY JET RAPIDLY BREAKS DOWN AND SHIFTS
TO A MUCH LIGHTER WESTERLY FLOW...WITH JUST A FEW LEFT-OVER
SPRINKLES OR LIGHT SHOWERS REMAINING BY LATE TONIGHT...MAINLY OVER
SOUTHERN GILA COUNTY. TEMPERATURES TODAY ARE EXPECTED TO BE MUCH
COOLER THAN WHAT WE SAW ON SUNDAY...WITH MANY LOWER DESERT LOCATIONS
ACROSS SOUTH-CENTRAL ARIZONA STAYING DOWN IN THE 50S THROUGH MUCH OF
THE DAY. LOWS TONIGHT ARE EXPECTED TO FALL INTO THE 40S AT MOST
LOWER DESERT LOCATIONS...WHICH IS NOW A FEW DEGREES BELOW NORMAL FOR
THIS TIME OF YEAR.

TUESDAY THROUGH THURSDAY...
A MUCH DRIER WEATHER REGIME IS EXPECTED AS NORTHWESTERLY FLOW ALOFT
BECOMES ESTABLISHED ACROSS THE REGION...WITH JUST A FEW SHOWERS
POSSIBLE FROM TIME-TO-TIME OVER THE HIGHER TERRAIN EAST OF
PHOENIX...AS WEAK SHORTWAVES EMBEDDED IN THIS NW FLOW MOVE ACROSS
EXTREME EASTERN AZ. TEMPERATURES ARE EXPECTED TO MAKE A SLOW REBOUND
AS 500MB HEIGHTS RISE...WITH HIGHS RETURNING TO NEAR-NORMAL VALUES
BY THURSDAY.

FRIDAY INTO NEXT WEEKEND...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A DECENT CHANCE FOR HIGHS IN THE 80S ACROSS THE LOWER
DESERTS BY NEXT WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
WIDESPREAD IMPACTS INCLUDING LOW CIGS...RAIN SHOWERS...LOWERED
VSBY...AND GUSTY WIND SHIFTS WILL BE COMMON ACROSS CNTRL ARIZONA
TERMINALS THROUGH THIS AFTERNOON. CIGS HAVE ALREADY STARTED LOWERING
BLO 6K FT WITH MTN OBSCURATION PREVAILING THROUGH THE DAY.
CONFIDENCE IS ONLY MODEST IN TIMING THE HEAVIEST SQUALLS INTO
KPHX...THOUGH MOST HIGH RESOLUTION MODELS SUGGEST A COUPLE HOURS
AROUND 18Z WITH PREVAILING MVFR CONDITIONS ALONG WITH A DISTINCT
WIND SHIFT. SOME BRIEF PERIODS OF IFR MAY ALSO BE POSSIBLE IN THE
HEAVIEST SHOWERS...THOUGH CONFIDENCE AND TEMPORAL DURATION TOO LOW
TO MENTION IN THIS TAF PACKAGE. CONFIDENCE IS VERY LOW BEYOND
00Z...AND SOME ADDITIONAL SCT SHRA AND CIGS FALLING BACK BLO 6K FT
MAY BE POSSIBLE.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
PREVAILING RAIN WILL MOVE EAST OF TERMINAL SITES BY 15Z...HOWEVER
LINGER LOW LEVEL MOISTURE HAS ALLOWED PATCHY MVFR TO LIFR CIGS TO
DEVELOP. NOT A LOT OF CONFIDENCE IN HOW LONG THESE LOWER CATEGORIES
WILL PERSIST...THOUGH MODELS SUGGEST ONLY A BRIEF TIME. WITH THE
UPPER LEVEL SYSTEM MOVING THROUGH SOUTHEAST CALIFORNIA THIS
AFTERNOON...CONFIDENCE IS BETTER THAN GUSTY WEST WINDS WILL DEVELOP
WITH SOME SHRA REDEVELOPMENT. CONDITIONS WILL IMPROVE QUICKLY AFTER
SUNSET.


AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
STRONG HIGH PRESSURE AND MUCH DRIER CONDITIONS WILL MOVE BACK INTO
THE DISTRICT DURING THE LATTER HALF OF THE WEEK. TEMPERATURES WILL
REBOUND BACK INTO A NORMAL TO SLIGHTLY ABOVE NORMAL RANGE...WHILE
AFTERNOON HUMIDITY LEVELS RETURN INTO A 15 TO 25 PERCENT RANGE.
OVERNIGHT RECOVERY WILL BE GOOD. PERIODS OF GUSTY NORTH WINDS DOWN
THE COLORADO RIVER VALLEY WILL BE LIKELY WEDNESDAY AFTERNOON...WHILE
OCCASIONAL PERIODS OF STRONGER EASTERLY WINDS OVER RIDGE TOPS OF
CENTRAL ARIZONA MAY BE COMMON LATE IN THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ020>021.
     FLOOD WATCH FROM MIDNIGHT TONIGHT THROUGH 8 PM MONDAY
     AZZ022>024.

CA...FLOOD WATCH UNTIL 12 PM MONDAY CAZ031>033.

&&

$$

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

DISCUSSION...PERCHA
AVIATION...MO
FIRE WEATHER...MO







000
FXUS65 KPSR 020930
AFDPSR

AREA FORECAST DISCUSSION ...CORRECTION
NATIONAL WEATHER SERVICE PHOENIX AZ
230 AM MST MON MAR 2 2015

...POTENTIAL FOR HEAVY RAIN AFFECTING THE SOUTHWEST AND SOUTH
CENTRAL AZ DESERTS THROUGH LATE TODAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL EXPAND FROM SOUTHEAST CALIFORNIA INTO
ARIZONA TODAY...AND WILL SLOWLY SHIFT EASTWARD DURING THE COURSE OF
THE DAY. PERIODS OF MODERATE TO HEAVY RAIN ARE
ANTICIPATED...ESPECIALLY OVER THE HIGHER TERRAIN AND FOOTHILL
LOCATIONS OF SOUTH CENTRAL ARIZONA. THERE WILL ALSO BE A SLIGHT
CHANCE OF THUNDERSTORMS AS WELL...MAINLY DURING THE AFTERNOON AND
EARLY EVENING HOURS. COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS
SYSTEM WITH BELOW NORMAL READINGS EXPECTED FROM TODAY THROUGH MID
WEEK. A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...

TODAY AND TONIGHT...

THE WELL-ADVERTISED UPPER-LEVEL LOW CENTER...THAT HAS BEEN DROPPING
SOUTHWARD ALONG THE WEST COAST OVER THE LAST FEW DAYS...IS FINALLY
BEGINNING TO MOVE OFF TO THE EAST...INTO SOUTHERN CA THIS MORNING AS
THE LONG-AWAITED UPSTREAM KICKER...MOVES SOUTHWARD ACROSS NORTHERN
CA TOWARDS THIS LOW CENTER. THIS SYSTEM...WHICH BROUGHT RAINFALL
AMOUNTS RANGING FROM 0.25 INCH TO JUST OVER 1.00 INCH TO MUCH OF SE
CA YESTERDAY AND LAST NIGHT...WHICH WAS FORECAST WELL BY THE GFS
MODEL OUTPUT...IS EXPECTED TO MOVE INTO WESTERN ARIZONA THIS
MORNING...THEN ACROSS SOUTH-CENTRAL ARIZONA THIS AFTERNOON/EVENING.
NOW THAT THE MAIN UPPER LOW IS FINALLY SHIFTING TO THE EAST...THE
BAROCLINIC LEAF AND ASSOCIATED AREA OF RAINFALL IS ALSO MOVING INTO
EXTREME WESTERN ARIZONA AS OF THIS HOUR...BRINGING LIGHT TO MODERATE
RAINFALL TO PARTS OF YUMA AND LA PAZ COUNTY. THE LATEST GFS AND HRRR
HI-RES MODELS ARE NOW IN GOOD AGREEMENT ON THE TIMING OF THIS SYSTEM
AS IT CONTINUES TO MOVE EASTWARD ACROSS AZ TODAY...WITH BOTH OF THEM
BRINGING RAINFALL TO THE GREATER PHX AREA AROUND DAYBREAK/DURING THE
MORNING COMMUTE...THEN INTO THE EASTERNMOST PORTION OF OUR CWA
(SOUTHERN GILA COUNTY) BY EARLY AFTERNOON.

ALTHOUGH THIS HAS TURNED INTO A FAIRLY PROGRESSIVE SYSTEM (AFTER A
DELAYED ARRIVAL)...IT STILL LOOKS LIKE A FAIRLY ROBUST SYSTEM...AND
IT IS STILL EXPECTED TO BRING LOCALLY HEAVY RAIN TO SOUTH-CENTRAL
ARIZONA TODAY...ESPECIALLY OVER THE HIGHER TERRAIN NORTH AND EAST OF
PHOENIX. THIS IS DUE TO THE FACT THAT A PLUME OF VERY MOIST
AIR...WITH PWATS AROUND ONE INCH IS EXPECTED TO STREAM NORTH OVER
THE REGION TODAY ALONG AND JUST AHEAD OF THE MAIN SURFACE
FRONT/BAROCLINIC ZONE. THIS DEEP MOISTURE...COMBINED WITH GOOD
BAROCLINICITY...STRONG LOW-LEVEL UPSLOPE SOUTHERLY FLOW (850MB WINDS
IN THE 30-40KT RANGE)...AND INFLUENCE FROM THE RIGHT-ENTRANCE REGION
OF THE JET IS EXPECTED TO PRODUCE A RATHER SOLID BAND OF
MODERATE-HEAVY RAINFALL DURING ITS PASSAGE ACROSS SOUTH-CENTRAL
ARIZONA. ALSO...EVEN THOUGH THERE IS NOW A WHOLE LOT OF CAPE IN THE
FORECAST SOUNDINGS (A COUPLE HUNDRED JOULES/KG AT MOST)...THERE
APPEARS TO BE ENOUGH LIFT TO TRIGGER A FEW EMBEDDED THUNDERSTORMS
THIS AFTERNOON AS THE FRONT MOVES THROUGH. THE COMBINATION OF THE
GENERAL RAINFALL...RANGING FROM AROUND 1/2 INCH OVER WESTERN
MARICOPA COUNTY TO AS MUCH AS 2.00 INCHES IN THE MOST FAVORED
LOCATIONS OVER EXTREME NORTH AND NORTHEAST MARICOPA COUNTY...WITH
THESE HEAVIER SHOWERS...WILL LIKELY PRODUCE AT LEAST SOME LOCAL
FLOODING PROBLEMS IN OUR WASHES...HIGHWAY DIPS...AND LOW-LYING
AREAS. THERE COULD ALSO BE SOME RISES IN SOME OF OUR SMALLER CREEKS
AND STREAMS...ESPECIALLY OVER THE HIGHER TERRAIN. SNOWFALL...IF
ANY...IS STILL EXPECTED TO BE CONFINED TO OUR HIGHEST PEAKS...WHERE
A DUSTING TO PERHAPS AN INCH COULD FALL BEFORE THE PRECIP ENDS THIS
EVENING. ON THE OTHER HAND...MUCH GREATER SNOWFALL AMOUNTS ARE
EXPECTED FURTHER NORTH AND EAST...FROM THE FLAGSTAFF AREA EAST
ACROSS THE RIM COUNTY INTO THE WHITE MTNS.

IT NOW APPEARS THAT THE RAINFALL SHOULD DIMINISH RATHER RAPIDLY THIS
EVENING FROM WEST TO EAST AS THE MAIN UPPER TROF MOVES OFF TO THE
EAST AND THE LOW-LEVEL SOUTHERLY JET RAPIDLY BREAKS DOWN AND SHIFTS
TO A MUCH LIGHTER WESTERLY FLOW...WITH JUST A FEW LEFT-OVER
SPRINKLES OR LIGHT SHOWERS REMAINING BY LATE TONIGHT...MAINLY OVER
SOUTHERN GILA COUNTY. TEMPERATURES TODAY ARE EXPECTED TO BE MUCH
COOLER THAN WHAT WE SAW ON SUNDAY...WITH MANY LOWER DESERT LOCATIONS
ACROSS SOUTH-CENTRAL ARIZONA STAYING DOWN IN THE 50S THROUGH MUCH OF
THE DAY. LOWS TONIGHT ARE EXPECTED TO FALL INTO THE 40S AT MOST
LOWER DESERT LOCATIONS...WHICH IS NOW A FEW DEGREES BELOW NORMAL FOR
THIS TIME OF YEAR.

TUESDAY THROUGH THURSDAY...
A MUCH DRIER WEATHER REGIME IS EXPECTED AS NORTHWESTERLY FLOW ALOFT
BECOMES ESTABLISHED ACROSS THE REGION...WITH JUST A FEW SHOWERS
POSSIBLE FROM TIME-TO-TIME OVER THE HIGHER TERRAIN EAST OF
PHOENIX...AS WEAK SHORTWAVES EMBEDDED IN THIS NW FLOW MOVE ACROSS
EXTREME EASTERN AZ. TEMPERATURES ARE EXPECTED TO MAKE A SLOW REBOUND
AS 500MB HEIGHTS RISE...WITH HIGHS RETURNING TO NEAR-NORMAL VALUES
BY THURSDAY.

FRIDAY INTO NEXT WEEKEND...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A DECENT CHANCE FOR HIGHS IN THE 80S ACROSS THE LOWER
DESERTS BY NEXT WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
A MOIST COLD FRONT APPROACHING FOR MONDAY MORNING. CLOUDS AND
SHOWERS WILL SLOWLY INCREASE AFTER 08Z MON...REACHING A PEAK AROUND
18Z MON. AS A RESULT...BKN CLDS BETWEEN 6-8 THSD AGL THROUGH 15Z
MON...THEN LOWERING TO NEAR 2 THSD BKN IN MODERATE RAIN AT TIMES
BETWEEN 15Z AND 21Z MON. SOUTH WIND 6 TO 8 KNOTS...BECOMING GUSTY
NEAR 20 KNOTS AROUND 17Z WITH SHOWERS.


SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
A MOIST COLD FRONT MOVING THROUGH THE AREA BETWEEN 07Z-12Z MON.  AS
A RESULT...OCCASIONAL MVFR CONDITIONS IN CLOUDS AND RAIN. CIGS NEAR
3 THSD AGL WITH OCCASIONAL MODERATE RAIN THROUGH 11Z...CLOUDS
LIFTING AND RAIN ENDING AFTER 13Z MON.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ020>021.
     FLOOD WATCH FROM MIDNIGHT TONIGHT THROUGH 8 PM MONDAY
     AZZ022>024.

CA...FLOOD WATCH UNTIL 12 PM MONDAY CAZ031>033.

&&

$$

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

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







000
FXUS65 KPSR 020930
AFDPSR

AREA FORECAST DISCUSSION ...CORRECTION
NATIONAL WEATHER SERVICE PHOENIX AZ
230 AM MST MON MAR 2 2015

...POTENTIAL FOR HEAVY RAIN AFFECTING THE SOUTHWEST AND SOUTH
CENTRAL AZ DESERTS THROUGH LATE TODAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL EXPAND FROM SOUTHEAST CALIFORNIA INTO
ARIZONA TODAY...AND WILL SLOWLY SHIFT EASTWARD DURING THE COURSE OF
THE DAY. PERIODS OF MODERATE TO HEAVY RAIN ARE
ANTICIPATED...ESPECIALLY OVER THE HIGHER TERRAIN AND FOOTHILL
LOCATIONS OF SOUTH CENTRAL ARIZONA. THERE WILL ALSO BE A SLIGHT
CHANCE OF THUNDERSTORMS AS WELL...MAINLY DURING THE AFTERNOON AND
EARLY EVENING HOURS. COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS
SYSTEM WITH BELOW NORMAL READINGS EXPECTED FROM TODAY THROUGH MID
WEEK. A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...

TODAY AND TONIGHT...

THE WELL-ADVERTISED UPPER-LEVEL LOW CENTER...THAT HAS BEEN DROPPING
SOUTHWARD ALONG THE WEST COAST OVER THE LAST FEW DAYS...IS FINALLY
BEGINNING TO MOVE OFF TO THE EAST...INTO SOUTHERN CA THIS MORNING AS
THE LONG-AWAITED UPSTREAM KICKER...MOVES SOUTHWARD ACROSS NORTHERN
CA TOWARDS THIS LOW CENTER. THIS SYSTEM...WHICH BROUGHT RAINFALL
AMOUNTS RANGING FROM 0.25 INCH TO JUST OVER 1.00 INCH TO MUCH OF SE
CA YESTERDAY AND LAST NIGHT...WHICH WAS FORECAST WELL BY THE GFS
MODEL OUTPUT...IS EXPECTED TO MOVE INTO WESTERN ARIZONA THIS
MORNING...THEN ACROSS SOUTH-CENTRAL ARIZONA THIS AFTERNOON/EVENING.
NOW THAT THE MAIN UPPER LOW IS FINALLY SHIFTING TO THE EAST...THE
BAROCLINIC LEAF AND ASSOCIATED AREA OF RAINFALL IS ALSO MOVING INTO
EXTREME WESTERN ARIZONA AS OF THIS HOUR...BRINGING LIGHT TO MODERATE
RAINFALL TO PARTS OF YUMA AND LA PAZ COUNTY. THE LATEST GFS AND HRRR
HI-RES MODELS ARE NOW IN GOOD AGREEMENT ON THE TIMING OF THIS SYSTEM
AS IT CONTINUES TO MOVE EASTWARD ACROSS AZ TODAY...WITH BOTH OF THEM
BRINGING RAINFALL TO THE GREATER PHX AREA AROUND DAYBREAK/DURING THE
MORNING COMMUTE...THEN INTO THE EASTERNMOST PORTION OF OUR CWA
(SOUTHERN GILA COUNTY) BY EARLY AFTERNOON.

ALTHOUGH THIS HAS TURNED INTO A FAIRLY PROGRESSIVE SYSTEM (AFTER A
DELAYED ARRIVAL)...IT STILL LOOKS LIKE A FAIRLY ROBUST SYSTEM...AND
IT IS STILL EXPECTED TO BRING LOCALLY HEAVY RAIN TO SOUTH-CENTRAL
ARIZONA TODAY...ESPECIALLY OVER THE HIGHER TERRAIN NORTH AND EAST OF
PHOENIX. THIS IS DUE TO THE FACT THAT A PLUME OF VERY MOIST
AIR...WITH PWATS AROUND ONE INCH IS EXPECTED TO STREAM NORTH OVER
THE REGION TODAY ALONG AND JUST AHEAD OF THE MAIN SURFACE
FRONT/BAROCLINIC ZONE. THIS DEEP MOISTURE...COMBINED WITH GOOD
BAROCLINICITY...STRONG LOW-LEVEL UPSLOPE SOUTHERLY FLOW (850MB WINDS
IN THE 30-40KT RANGE)...AND INFLUENCE FROM THE RIGHT-ENTRANCE REGION
OF THE JET IS EXPECTED TO PRODUCE A RATHER SOLID BAND OF
MODERATE-HEAVY RAINFALL DURING ITS PASSAGE ACROSS SOUTH-CENTRAL
ARIZONA. ALSO...EVEN THOUGH THERE IS NOW A WHOLE LOT OF CAPE IN THE
FORECAST SOUNDINGS (A COUPLE HUNDRED JOULES/KG AT MOST)...THERE
APPEARS TO BE ENOUGH LIFT TO TRIGGER A FEW EMBEDDED THUNDERSTORMS
THIS AFTERNOON AS THE FRONT MOVES THROUGH. THE COMBINATION OF THE
GENERAL RAINFALL...RANGING FROM AROUND 1/2 INCH OVER WESTERN
MARICOPA COUNTY TO AS MUCH AS 2.00 INCHES IN THE MOST FAVORED
LOCATIONS OVER EXTREME NORTH AND NORTHEAST MARICOPA COUNTY...WITH
THESE HEAVIER SHOWERS...WILL LIKELY PRODUCE AT LEAST SOME LOCAL
FLOODING PROBLEMS IN OUR WASHES...HIGHWAY DIPS...AND LOW-LYING
AREAS. THERE COULD ALSO BE SOME RISES IN SOME OF OUR SMALLER CREEKS
AND STREAMS...ESPECIALLY OVER THE HIGHER TERRAIN. SNOWFALL...IF
ANY...IS STILL EXPECTED TO BE CONFINED TO OUR HIGHEST PEAKS...WHERE
A DUSTING TO PERHAPS AN INCH COULD FALL BEFORE THE PRECIP ENDS THIS
EVENING. ON THE OTHER HAND...MUCH GREATER SNOWFALL AMOUNTS ARE
EXPECTED FURTHER NORTH AND EAST...FROM THE FLAGSTAFF AREA EAST
ACROSS THE RIM COUNTY INTO THE WHITE MTNS.

IT NOW APPEARS THAT THE RAINFALL SHOULD DIMINISH RATHER RAPIDLY THIS
EVENING FROM WEST TO EAST AS THE MAIN UPPER TROF MOVES OFF TO THE
EAST AND THE LOW-LEVEL SOUTHERLY JET RAPIDLY BREAKS DOWN AND SHIFTS
TO A MUCH LIGHTER WESTERLY FLOW...WITH JUST A FEW LEFT-OVER
SPRINKLES OR LIGHT SHOWERS REMAINING BY LATE TONIGHT...MAINLY OVER
SOUTHERN GILA COUNTY. TEMPERATURES TODAY ARE EXPECTED TO BE MUCH
COOLER THAN WHAT WE SAW ON SUNDAY...WITH MANY LOWER DESERT LOCATIONS
ACROSS SOUTH-CENTRAL ARIZONA STAYING DOWN IN THE 50S THROUGH MUCH OF
THE DAY. LOWS TONIGHT ARE EXPECTED TO FALL INTO THE 40S AT MOST
LOWER DESERT LOCATIONS...WHICH IS NOW A FEW DEGREES BELOW NORMAL FOR
THIS TIME OF YEAR.

TUESDAY THROUGH THURSDAY...
A MUCH DRIER WEATHER REGIME IS EXPECTED AS NORTHWESTERLY FLOW ALOFT
BECOMES ESTABLISHED ACROSS THE REGION...WITH JUST A FEW SHOWERS
POSSIBLE FROM TIME-TO-TIME OVER THE HIGHER TERRAIN EAST OF
PHOENIX...AS WEAK SHORTWAVES EMBEDDED IN THIS NW FLOW MOVE ACROSS
EXTREME EASTERN AZ. TEMPERATURES ARE EXPECTED TO MAKE A SLOW REBOUND
AS 500MB HEIGHTS RISE...WITH HIGHS RETURNING TO NEAR-NORMAL VALUES
BY THURSDAY.

FRIDAY INTO NEXT WEEKEND...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A DECENT CHANCE FOR HIGHS IN THE 80S ACROSS THE LOWER
DESERTS BY NEXT WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
A MOIST COLD FRONT APPROACHING FOR MONDAY MORNING. CLOUDS AND
SHOWERS WILL SLOWLY INCREASE AFTER 08Z MON...REACHING A PEAK AROUND
18Z MON. AS A RESULT...BKN CLDS BETWEEN 6-8 THSD AGL THROUGH 15Z
MON...THEN LOWERING TO NEAR 2 THSD BKN IN MODERATE RAIN AT TIMES
BETWEEN 15Z AND 21Z MON. SOUTH WIND 6 TO 8 KNOTS...BECOMING GUSTY
NEAR 20 KNOTS AROUND 17Z WITH SHOWERS.


SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
A MOIST COLD FRONT MOVING THROUGH THE AREA BETWEEN 07Z-12Z MON.  AS
A RESULT...OCCASIONAL MVFR CONDITIONS IN CLOUDS AND RAIN. CIGS NEAR
3 THSD AGL WITH OCCASIONAL MODERATE RAIN THROUGH 11Z...CLOUDS
LIFTING AND RAIN ENDING AFTER 13Z MON.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ020>021.
     FLOOD WATCH FROM MIDNIGHT TONIGHT THROUGH 8 PM MONDAY
     AZZ022>024.

CA...FLOOD WATCH UNTIL 12 PM MONDAY CAZ031>033.

&&

$$

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

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






000
FXUS65 KPSR 020930
AFDPSR

AREA FORECAST DISCUSSION ...CORRECTION
NATIONAL WEATHER SERVICE PHOENIX AZ
230 AM MST MON MAR 2 2015

...POTENTIAL FOR HEAVY RAIN AFFECTING THE SOUTHWEST AND SOUTH
CENTRAL AZ DESERTS THROUGH LATE TODAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL EXPAND FROM SOUTHEAST CALIFORNIA INTO
ARIZONA TODAY...AND WILL SLOWLY SHIFT EASTWARD DURING THE COURSE OF
THE DAY. PERIODS OF MODERATE TO HEAVY RAIN ARE
ANTICIPATED...ESPECIALLY OVER THE HIGHER TERRAIN AND FOOTHILL
LOCATIONS OF SOUTH CENTRAL ARIZONA. THERE WILL ALSO BE A SLIGHT
CHANCE OF THUNDERSTORMS AS WELL...MAINLY DURING THE AFTERNOON AND
EARLY EVENING HOURS. COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS
SYSTEM WITH BELOW NORMAL READINGS EXPECTED FROM TODAY THROUGH MID
WEEK. A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...

TODAY AND TONIGHT...

THE WELL-ADVERTISED UPPER-LEVEL LOW CENTER...THAT HAS BEEN DROPPING
SOUTHWARD ALONG THE WEST COAST OVER THE LAST FEW DAYS...IS FINALLY
BEGINNING TO MOVE OFF TO THE EAST...INTO SOUTHERN CA THIS MORNING AS
THE LONG-AWAITED UPSTREAM KICKER...MOVES SOUTHWARD ACROSS NORTHERN
CA TOWARDS THIS LOW CENTER. THIS SYSTEM...WHICH BROUGHT RAINFALL
AMOUNTS RANGING FROM 0.25 INCH TO JUST OVER 1.00 INCH TO MUCH OF SE
CA YESTERDAY AND LAST NIGHT...WHICH WAS FORECAST WELL BY THE GFS
MODEL OUTPUT...IS EXPECTED TO MOVE INTO WESTERN ARIZONA THIS
MORNING...THEN ACROSS SOUTH-CENTRAL ARIZONA THIS AFTERNOON/EVENING.
NOW THAT THE MAIN UPPER LOW IS FINALLY SHIFTING TO THE EAST...THE
BAROCLINIC LEAF AND ASSOCIATED AREA OF RAINFALL IS ALSO MOVING INTO
EXTREME WESTERN ARIZONA AS OF THIS HOUR...BRINGING LIGHT TO MODERATE
RAINFALL TO PARTS OF YUMA AND LA PAZ COUNTY. THE LATEST GFS AND HRRR
HI-RES MODELS ARE NOW IN GOOD AGREEMENT ON THE TIMING OF THIS SYSTEM
AS IT CONTINUES TO MOVE EASTWARD ACROSS AZ TODAY...WITH BOTH OF THEM
BRINGING RAINFALL TO THE GREATER PHX AREA AROUND DAYBREAK/DURING THE
MORNING COMMUTE...THEN INTO THE EASTERNMOST PORTION OF OUR CWA
(SOUTHERN GILA COUNTY) BY EARLY AFTERNOON.

ALTHOUGH THIS HAS TURNED INTO A FAIRLY PROGRESSIVE SYSTEM (AFTER A
DELAYED ARRIVAL)...IT STILL LOOKS LIKE A FAIRLY ROBUST SYSTEM...AND
IT IS STILL EXPECTED TO BRING LOCALLY HEAVY RAIN TO SOUTH-CENTRAL
ARIZONA TODAY...ESPECIALLY OVER THE HIGHER TERRAIN NORTH AND EAST OF
PHOENIX. THIS IS DUE TO THE FACT THAT A PLUME OF VERY MOIST
AIR...WITH PWATS AROUND ONE INCH IS EXPECTED TO STREAM NORTH OVER
THE REGION TODAY ALONG AND JUST AHEAD OF THE MAIN SURFACE
FRONT/BAROCLINIC ZONE. THIS DEEP MOISTURE...COMBINED WITH GOOD
BAROCLINICITY...STRONG LOW-LEVEL UPSLOPE SOUTHERLY FLOW (850MB WINDS
IN THE 30-40KT RANGE)...AND INFLUENCE FROM THE RIGHT-ENTRANCE REGION
OF THE JET IS EXPECTED TO PRODUCE A RATHER SOLID BAND OF
MODERATE-HEAVY RAINFALL DURING ITS PASSAGE ACROSS SOUTH-CENTRAL
ARIZONA. ALSO...EVEN THOUGH THERE IS NOW A WHOLE LOT OF CAPE IN THE
FORECAST SOUNDINGS (A COUPLE HUNDRED JOULES/KG AT MOST)...THERE
APPEARS TO BE ENOUGH LIFT TO TRIGGER A FEW EMBEDDED THUNDERSTORMS
THIS AFTERNOON AS THE FRONT MOVES THROUGH. THE COMBINATION OF THE
GENERAL RAINFALL...RANGING FROM AROUND 1/2 INCH OVER WESTERN
MARICOPA COUNTY TO AS MUCH AS 2.00 INCHES IN THE MOST FAVORED
LOCATIONS OVER EXTREME NORTH AND NORTHEAST MARICOPA COUNTY...WITH
THESE HEAVIER SHOWERS...WILL LIKELY PRODUCE AT LEAST SOME LOCAL
FLOODING PROBLEMS IN OUR WASHES...HIGHWAY DIPS...AND LOW-LYING
AREAS. THERE COULD ALSO BE SOME RISES IN SOME OF OUR SMALLER CREEKS
AND STREAMS...ESPECIALLY OVER THE HIGHER TERRAIN. SNOWFALL...IF
ANY...IS STILL EXPECTED TO BE CONFINED TO OUR HIGHEST PEAKS...WHERE
A DUSTING TO PERHAPS AN INCH COULD FALL BEFORE THE PRECIP ENDS THIS
EVENING. ON THE OTHER HAND...MUCH GREATER SNOWFALL AMOUNTS ARE
EXPECTED FURTHER NORTH AND EAST...FROM THE FLAGSTAFF AREA EAST
ACROSS THE RIM COUNTY INTO THE WHITE MTNS.

IT NOW APPEARS THAT THE RAINFALL SHOULD DIMINISH RATHER RAPIDLY THIS
EVENING FROM WEST TO EAST AS THE MAIN UPPER TROF MOVES OFF TO THE
EAST AND THE LOW-LEVEL SOUTHERLY JET RAPIDLY BREAKS DOWN AND SHIFTS
TO A MUCH LIGHTER WESTERLY FLOW...WITH JUST A FEW LEFT-OVER
SPRINKLES OR LIGHT SHOWERS REMAINING BY LATE TONIGHT...MAINLY OVER
SOUTHERN GILA COUNTY. TEMPERATURES TODAY ARE EXPECTED TO BE MUCH
COOLER THAN WHAT WE SAW ON SUNDAY...WITH MANY LOWER DESERT LOCATIONS
ACROSS SOUTH-CENTRAL ARIZONA STAYING DOWN IN THE 50S THROUGH MUCH OF
THE DAY. LOWS TONIGHT ARE EXPECTED TO FALL INTO THE 40S AT MOST
LOWER DESERT LOCATIONS...WHICH IS NOW A FEW DEGREES BELOW NORMAL FOR
THIS TIME OF YEAR.

TUESDAY THROUGH THURSDAY...
A MUCH DRIER WEATHER REGIME IS EXPECTED AS NORTHWESTERLY FLOW ALOFT
BECOMES ESTABLISHED ACROSS THE REGION...WITH JUST A FEW SHOWERS
POSSIBLE FROM TIME-TO-TIME OVER THE HIGHER TERRAIN EAST OF
PHOENIX...AS WEAK SHORTWAVES EMBEDDED IN THIS NW FLOW MOVE ACROSS
EXTREME EASTERN AZ. TEMPERATURES ARE EXPECTED TO MAKE A SLOW REBOUND
AS 500MB HEIGHTS RISE...WITH HIGHS RETURNING TO NEAR-NORMAL VALUES
BY THURSDAY.

FRIDAY INTO NEXT WEEKEND...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A DECENT CHANCE FOR HIGHS IN THE 80S ACROSS THE LOWER
DESERTS BY NEXT WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
A MOIST COLD FRONT APPROACHING FOR MONDAY MORNING. CLOUDS AND
SHOWERS WILL SLOWLY INCREASE AFTER 08Z MON...REACHING A PEAK AROUND
18Z MON. AS A RESULT...BKN CLDS BETWEEN 6-8 THSD AGL THROUGH 15Z
MON...THEN LOWERING TO NEAR 2 THSD BKN IN MODERATE RAIN AT TIMES
BETWEEN 15Z AND 21Z MON. SOUTH WIND 6 TO 8 KNOTS...BECOMING GUSTY
NEAR 20 KNOTS AROUND 17Z WITH SHOWERS.


SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
A MOIST COLD FRONT MOVING THROUGH THE AREA BETWEEN 07Z-12Z MON.  AS
A RESULT...OCCASIONAL MVFR CONDITIONS IN CLOUDS AND RAIN. CIGS NEAR
3 THSD AGL WITH OCCASIONAL MODERATE RAIN THROUGH 11Z...CLOUDS
LIFTING AND RAIN ENDING AFTER 13Z MON.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ020>021.
     FLOOD WATCH FROM MIDNIGHT TONIGHT THROUGH 8 PM MONDAY
     AZZ022>024.

CA...FLOOD WATCH UNTIL 12 PM MONDAY CAZ031>033.

&&

$$

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

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






000
FXUS65 KPSR 020930
AFDPSR

AREA FORECAST DISCUSSION ...CORRECTION
NATIONAL WEATHER SERVICE PHOENIX AZ
230 AM MST MON MAR 2 2015

...POTENTIAL FOR HEAVY RAIN AFFECTING THE SOUTHWEST AND SOUTH
CENTRAL AZ DESERTS THROUGH LATE TODAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL EXPAND FROM SOUTHEAST CALIFORNIA INTO
ARIZONA TODAY...AND WILL SLOWLY SHIFT EASTWARD DURING THE COURSE OF
THE DAY. PERIODS OF MODERATE TO HEAVY RAIN ARE
ANTICIPATED...ESPECIALLY OVER THE HIGHER TERRAIN AND FOOTHILL
LOCATIONS OF SOUTH CENTRAL ARIZONA. THERE WILL ALSO BE A SLIGHT
CHANCE OF THUNDERSTORMS AS WELL...MAINLY DURING THE AFTERNOON AND
EARLY EVENING HOURS. COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS
SYSTEM WITH BELOW NORMAL READINGS EXPECTED FROM TODAY THROUGH MID
WEEK. A RETURN TO ABOVE NORMAL TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...

TODAY AND TONIGHT...

THE WELL-ADVERTISED UPPER-LEVEL LOW CENTER...THAT HAS BEEN DROPPING
SOUTHWARD ALONG THE WEST COAST OVER THE LAST FEW DAYS...IS FINALLY
BEGINNING TO MOVE OFF TO THE EAST...INTO SOUTHERN CA THIS MORNING AS
THE LONG-AWAITED UPSTREAM KICKER...MOVES SOUTHWARD ACROSS NORTHERN
CA TOWARDS THIS LOW CENTER. THIS SYSTEM...WHICH BROUGHT RAINFALL
AMOUNTS RANGING FROM 0.25 INCH TO JUST OVER 1.00 INCH TO MUCH OF SE
CA YESTERDAY AND LAST NIGHT...WHICH WAS FORECAST WELL BY THE GFS
MODEL OUTPUT...IS EXPECTED TO MOVE INTO WESTERN ARIZONA THIS
MORNING...THEN ACROSS SOUTH-CENTRAL ARIZONA THIS AFTERNOON/EVENING.
NOW THAT THE MAIN UPPER LOW IS FINALLY SHIFTING TO THE EAST...THE
BAROCLINIC LEAF AND ASSOCIATED AREA OF RAINFALL IS ALSO MOVING INTO
EXTREME WESTERN ARIZONA AS OF THIS HOUR...BRINGING LIGHT TO MODERATE
RAINFALL TO PARTS OF YUMA AND LA PAZ COUNTY. THE LATEST GFS AND HRRR
HI-RES MODELS ARE NOW IN GOOD AGREEMENT ON THE TIMING OF THIS SYSTEM
AS IT CONTINUES TO MOVE EASTWARD ACROSS AZ TODAY...WITH BOTH OF THEM
BRINGING RAINFALL TO THE GREATER PHX AREA AROUND DAYBREAK/DURING THE
MORNING COMMUTE...THEN INTO THE EASTERNMOST PORTION OF OUR CWA
(SOUTHERN GILA COUNTY) BY EARLY AFTERNOON.

ALTHOUGH THIS HAS TURNED INTO A FAIRLY PROGRESSIVE SYSTEM (AFTER A
DELAYED ARRIVAL)...IT STILL LOOKS LIKE A FAIRLY ROBUST SYSTEM...AND
IT IS STILL EXPECTED TO BRING LOCALLY HEAVY RAIN TO SOUTH-CENTRAL
ARIZONA TODAY...ESPECIALLY OVER THE HIGHER TERRAIN NORTH AND EAST OF
PHOENIX. THIS IS DUE TO THE FACT THAT A PLUME OF VERY MOIST
AIR...WITH PWATS AROUND ONE INCH IS EXPECTED TO STREAM NORTH OVER
THE REGION TODAY ALONG AND JUST AHEAD OF THE MAIN SURFACE
FRONT/BAROCLINIC ZONE. THIS DEEP MOISTURE...COMBINED WITH GOOD
BAROCLINICITY...STRONG LOW-LEVEL UPSLOPE SOUTHERLY FLOW (850MB WINDS
IN THE 30-40KT RANGE)...AND INFLUENCE FROM THE RIGHT-ENTRANCE REGION
OF THE JET IS EXPECTED TO PRODUCE A RATHER SOLID BAND OF
MODERATE-HEAVY RAINFALL DURING ITS PASSAGE ACROSS SOUTH-CENTRAL
ARIZONA. ALSO...EVEN THOUGH THERE IS NOW A WHOLE LOT OF CAPE IN THE
FORECAST SOUNDINGS (A COUPLE HUNDRED JOULES/KG AT MOST)...THERE
APPEARS TO BE ENOUGH LIFT TO TRIGGER A FEW EMBEDDED THUNDERSTORMS
THIS AFTERNOON AS THE FRONT MOVES THROUGH. THE COMBINATION OF THE
GENERAL RAINFALL...RANGING FROM AROUND 1/2 INCH OVER WESTERN
MARICOPA COUNTY TO AS MUCH AS 2.00 INCHES IN THE MOST FAVORED
LOCATIONS OVER EXTREME NORTH AND NORTHEAST MARICOPA COUNTY...WITH
THESE HEAVIER SHOWERS...WILL LIKELY PRODUCE AT LEAST SOME LOCAL
FLOODING PROBLEMS IN OUR WASHES...HIGHWAY DIPS...AND LOW-LYING
AREAS. THERE COULD ALSO BE SOME RISES IN SOME OF OUR SMALLER CREEKS
AND STREAMS...ESPECIALLY OVER THE HIGHER TERRAIN. SNOWFALL...IF
ANY...IS STILL EXPECTED TO BE CONFINED TO OUR HIGHEST PEAKS...WHERE
A DUSTING TO PERHAPS AN INCH COULD FALL BEFORE THE PRECIP ENDS THIS
EVENING. ON THE OTHER HAND...MUCH GREATER SNOWFALL AMOUNTS ARE
EXPECTED FURTHER NORTH AND EAST...FROM THE FLAGSTAFF AREA EAST
ACROSS THE RIM COUNTY INTO THE WHITE MTNS.

IT NOW APPEARS THAT THE RAINFALL SHOULD DIMINISH RATHER RAPIDLY THIS
EVENING FROM WEST TO EAST AS THE MAIN UPPER TROF MOVES OFF TO THE
EAST AND THE LOW-LEVEL SOUTHERLY JET RAPIDLY BREAKS DOWN AND SHIFTS
TO A MUCH LIGHTER WESTERLY FLOW...WITH JUST A FEW LEFT-OVER
SPRINKLES OR LIGHT SHOWERS REMAINING BY LATE TONIGHT...MAINLY OVER
SOUTHERN GILA COUNTY. TEMPERATURES TODAY ARE EXPECTED TO BE MUCH
COOLER THAN WHAT WE SAW ON SUNDAY...WITH MANY LOWER DESERT LOCATIONS
ACROSS SOUTH-CENTRAL ARIZONA STAYING DOWN IN THE 50S THROUGH MUCH OF
THE DAY. LOWS TONIGHT ARE EXPECTED TO FALL INTO THE 40S AT MOST
LOWER DESERT LOCATIONS...WHICH IS NOW A FEW DEGREES BELOW NORMAL FOR
THIS TIME OF YEAR.

TUESDAY THROUGH THURSDAY...
A MUCH DRIER WEATHER REGIME IS EXPECTED AS NORTHWESTERLY FLOW ALOFT
BECOMES ESTABLISHED ACROSS THE REGION...WITH JUST A FEW SHOWERS
POSSIBLE FROM TIME-TO-TIME OVER THE HIGHER TERRAIN EAST OF
PHOENIX...AS WEAK SHORTWAVES EMBEDDED IN THIS NW FLOW MOVE ACROSS
EXTREME EASTERN AZ. TEMPERATURES ARE EXPECTED TO MAKE A SLOW REBOUND
AS 500MB HEIGHTS RISE...WITH HIGHS RETURNING TO NEAR-NORMAL VALUES
BY THURSDAY.

FRIDAY INTO NEXT WEEKEND...
A WARMING TREND IS EXPECTED TO CONTINUE THROUGH THIS PERIOD UNDER
MAINLY CLEAR SKIES AS HIGH PRESSURE STRENGTHENS OVER THE
REGION...WITH A DECENT CHANCE FOR HIGHS IN THE 80S ACROSS THE LOWER
DESERTS BY NEXT WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
A MOIST COLD FRONT APPROACHING FOR MONDAY MORNING. CLOUDS AND
SHOWERS WILL SLOWLY INCREASE AFTER 08Z MON...REACHING A PEAK AROUND
18Z MON. AS A RESULT...BKN CLDS BETWEEN 6-8 THSD AGL THROUGH 15Z
MON...THEN LOWERING TO NEAR 2 THSD BKN IN MODERATE RAIN AT TIMES
BETWEEN 15Z AND 21Z MON. SOUTH WIND 6 TO 8 KNOTS...BECOMING GUSTY
NEAR 20 KNOTS AROUND 17Z WITH SHOWERS.


SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
A MOIST COLD FRONT MOVING THROUGH THE AREA BETWEEN 07Z-12Z MON.  AS
A RESULT...OCCASIONAL MVFR CONDITIONS IN CLOUDS AND RAIN. CIGS NEAR
3 THSD AGL WITH OCCASIONAL MODERATE RAIN THROUGH 11Z...CLOUDS
LIFTING AND RAIN ENDING AFTER 13Z MON.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ020>021.
     FLOOD WATCH FROM MIDNIGHT TONIGHT THROUGH 8 PM MONDAY
     AZZ022>024.

CA...FLOOD WATCH UNTIL 12 PM MONDAY CAZ031>033.

&&

$$

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

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







000
FXUS65 KPSR 020330
AFDPSR

AREA FORECAST DISCUSSION ...CORRECTION
NATIONAL WEATHER SERVICE PHOENIX AZ
830 PM MST SUN MAR 1 2015

...POTENTIAL FOR HEAVY RAIN AFFECTING THE SOUTHWEST AND SOUTH
CENTRAL AZ DESERTS THROUGH LATE MONDAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL EXPAND FROM SOUTHEAST CALIFORNIA INTO
ARIZONA TONIGHT AND SLOWLY SHIFT EASTWARD DURING THE DAY MONDAY.
PERIODS OF MODERATE TO HEAVY RAIN ARE ANTICIPATED...ESPECIALLY OVER
HIGHER TERRAIN AND FOOTHILL LOCATIONS. THERE WILL ALSO BE A SLIGHT
CHANCE OF THUNDERSTORMS DURING THE DAY MONDAY...MAINLY OVER PORTIONS
OF ARIZONA. COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS SYSTEM WITH
BELOW NORMAL READINGS EXPECTED MONDAY THROUGH MID WEEK. A RETURN TO
ABOVE NORMAL TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
THE COLD UPPER TROF THAT HAD BEEN DEVELOPING SLOWLY SOUTH ALONG THE
CENTRAL AND SOUTHERN CA COAST THE PAST 36 HOURS...AND HAS BEEN
SLOWLY CIRCULATING APPRECIABLE AMOUNTS OF LOW LEVEL MOISTURE INTO
THE REGION...HAS BEGUN TO KICK INLAND THIS EVENING. SAT IMAGERY
SHOWED A WELL DEFINED KICKER TROF MOVING RAPIDLY SOUTH THROUGH THE
PACIFIC NORTHWEST UNDER NORTHERLY FLOW ALOFT.

AS A RESULT...REGIONAL UPPER AIR DATA SHOWED A PROFOUNDLY SHARP
BAROCLINIC ZONE ACROSS SOUTHERN CA/SOUTHERN NEVADA THAT HAS BACKED
AND INCREASED THE WINDS ALOFT SINCE MORNING. 700 MB WINDS ALONG THE
COLORADO RIVER WERE NEARLY SOUTH AT 40 KNOTS WHILE 300 MB WINDS WERE
WERE SOUTHWEST 100-120 KNOTS AND DIFLUENT. ALSO...MORE BOUNDARY
LAYER MOISTURE HAS TRANSPORTED NORTH ALONG THE FRONTAL ZONE AND
CURRENTLY FOCUSED IN SOUTHEAST CA/COLORADO RIVER WHERE FAST MOVING
BANDS OF PRECIP HAVE INCREASED THE PAST FEW HOURS.

THEREFORE AS THE COLD DYNAMICAL SYSTEM MOVES INLAND FROM OFFSHORE
SOUTHERN CA/NORTHERN BAJA TONIGHT...AN UPSWING IN PRECIP IS
EXPECTED. PRECIP WILL FOCUS ALONG THE COLORADO RIVER BY MIDNIGHT...
MOVING INTO SOUTHWEST AZ BY 12Z MON...THEN INTO CENTRAL AZ INCLUDING
PHOENIX BY 18Z MON. SINCE SOUTHERLY LOW LEVEL WINDS ARE FAIRLY
STRONG...ENHANCED UPSLOPE PRECIP WILL BE A BIG FACTOR IN THE
POTENTIAL FOR HEAVY RAIN AND RUNOFF. THE FLASH FLOOD WATCH THROUGH
MONDAY...FOCUSED IN THE UPSLOPE AREAS OF SOUTHWEST AND SOUTH CENTRAL
AZ WHERE MOUNTAIN WASHES DRAIN SOUTH INTO THE LOWER DESERTS LOOKS
GOOD FOR NOW.  A QUICK LOOK AT SOME OF THE OFFICE WARM COLLISION
COALESCENCE RAIN STUDIES INDICATE THE POTENTIAL FOR 0.50-0.60 INCHES
ON THE LOWER CENTRAL DESERTS TO NEARLY 2 INCHES IN THE MOUNTAINS AND
FOOTHILLS NORTHWEST THROUGH EAST OF PHOENIX MONDAY.

CURRENT FORECASTS LOOK IN GOOD SHAPE WITH HIGH PRECIP PROBABILITIES
AND THE POTENTIAL FOR HEAVY RAIN. NO UPDATES PLANNED. PREVIOUS
DISCUSSION BELOW STILL APPLIES.



.PREVIOUS DISCUSSION...302 PM MST...

REST OF TODAY THROUGH WEDNESDAY...
SHOWERS HAVE MOVED OVER OUR SOUTHEAST CALIFORNIA ZONES TODAY.
ISOLATED SHOWERS HAVE STARTED TO DEVELOP ELSEWHERE INCLUDING THE
PHOENIX AREA. MADE SOME EARLIER CHANGES TO THE FORECAST TO EXPAND
THE AREAL FLOOD WATCH TO SOUTHEAST CALIFORNIA. THE OTHER MAIN CHANGE
INCLUDED ANOTHER TIMING ADJUSTMENT FOR SOUTH-CENTRAL
ARIZONA...INCLUDING THE PHOENIX AREA...FOR A LATER START AND END. IN
SHORT...ANTICIPATE A SLOW RUNOFF RESPONSE TO THE RAINFALL BUT EXPECT
THERE WILL BE WASHES WITH SUFFICIENT FLOW TO CAUSE DANGEROUS
CONDITIONS AT SOME OF THE UNBRIDGED CROSSINGS. THERE WILL BE SOME
HIGHWAY DIPS AND OTHER LOW LYING AREAS THAT WILL SEE SOME INUNDATION
AS WELL. THE MAIN PRECIP MECHANISMS WITHIN THE LOW PRESSURE SYSTEM
ARE THE FRONTAL ZONE...CURRENTLY EXTENDING SOUTHWESTWARD FROM THE
MOHAVE DESERT...AND DYNAMICAL FORCING FROM SOME DIFFLUENCE RELATED
UPPER LEVEL DIVERGENCE...MAINLY NORTHWEST ARIZONA...AS WELL AS QG
FORCING FROM THE VORTICITY AND WARM AIR ADVECTION. THERE WILL ALSO
BE SOME INFLUENCE FROM THE RIGHT ENTRANCE REGION OF THE JET FOR
TOMORROW. THE FRONT IS ANTICIPATED TO MOVE THROUGH THE PHOENIX AREA
LATE MORNING/MIDDAY WITH PRECIP TRENDING DOWN FROM WEST TO EAST OVER
THE LOWER DESERTS OF ARIZONA IN MONDAY AFTERNOON...CONTINUING HIGHER
TERRAIN. THE MODELS ARE IN GENERALLY GOOD AGREEMENT ON THE TIMING
AND PLACEMENT OF THESE FEATURES THOUGH THE GFS IS A BIT MORE
GENEROUS WITH THE QG FORCING THAN NAM WHILE ECMWF IS A BIT SLOWER
WITH THE ONSET AND DEPARTURE OF PRECIP THAN NAM AND GFS. SEE THE
FLOOD WATCH FOR DETAILS ON THE TIMING AND PRECIP AMOUNTS. THE
UPSTREAM SYSTEM THAT WILL BE HELPING TO MOVE THIS MAIN ONE ALONG IS
CURRENTLY CENTERED NEAR THE ALASKA/CANADA BORDER. IT WILL RAPIDLY
MOVE DOWN THE COAST MONDAY AND THEN INTO NORTHWEST MEXICO TUESDAY.
MEANWHILE ANOTHER SHORT WAVE TRACKS THROUGH THE GREAT BASIN.
OUR FORECAST AREA WILL LARGELY BE BETWEEN THESE FEATURES BUT THEY
WILL CAUSE US TO KEEP A LINGERING SLIGHT CHANCE GOING...MAINLY OVER
SOUTH-CENTRAL ARIZONA. A MUCH WEAKER SHORT WAVE IS ADVERTISED TO
SLIDE DOWN FROM THE NORTH ON WEDNESDAY FOR SLIGHT CHANCES LIMITED TO
THE HIGHER TERRAIN OF SOUTH-CENTRAL AZ. SNOW LEVELS DROP TO NEAR
5000 FEET...INITIALLY OVER SOUTHEAST CALIFORNIA MONDAY MORNING THEN
EASTWARD TO SOUTH-CENTRAL ARIZONA BY EARLY MONDAY EVENING. THE
PRECIP WILL LARGELY BE OVER BY THE TIME THE SNOW LEVELS GET THAT LOW
AND THUS NO NOTABLE ACCUMULATIONS FOR OUR AREA...PERHAPS A DUSTING.
MADE A NUMBER OF TWEAKS TO THE POP/QPF GRIDS BUT NO MAJOR
ALTERATIONS FROM PREVIOUS PACKAGE. AS FOR TEMPERATURES...ANTICIPATE
LITTLE CHANGE OVER SOUTHEAST CALIFORNIA MONDAY SINCE THEY HAVE
ALREADY BEEN GETTING PRECIP. IT WILL BE MUCH COOLER THOUGH EAST OF
THE LOWER COLORADO RIVER VALLEY...ESPECIALLY SOUTH-CENTRAL ARIZONA.
IN FACT...PHOENIX AREA HIGH TEMP MONDAY MAY OCCUR BEFORE SUNRISE
WITH AFTERNOON PEAK IN THE 50S. WITH THE FOLLOW ON DISTURBANCES
TUESDAY AND WEDNESDAY...TEMPS WILL BE SLOW TO WARM UP THE FIRST HALF
OF THE WEEK.

FROM MID-WEEK ONWARD...RIDGING WILL TAKE HOLD ACROSS THE REGION AND
CONSEQUENTLY TEMPERATURES WILL ALSO CLIMB BACK ABOVE NORMAL BY LATE
WEEK INTO THE WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
A MOIST COLD FRONT APPROACHING FOR MONDAY MORNING. CLOUDS AND
SHOWERS WILL SLOWLY INCREASE AFTER 08Z MON...REACHING A PEAK AROUND
18Z MON. AS A RESULT...BKN CLDS BETWEEN 6-8 THSD AGL THROUGH 15Z
MON...THEN LOWERING TO NEAR 2 THSD BKN IN MODERATE RAIN AT TIMES
BETWEEN 15Z AND 21Z MON. SOUTH WIND 6 TO 8 KNOTS...BECOMING GUSTY
NEAR 20 KNOTS AROUND 17Z WITH SHOWERS.


SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
A MOIST COLD FRONT MOVING THROUGH THE AREA BETWEEN 07Z-12Z MON.  AS
A RESULT...OCCASIONAL MVFR CONDITIONS IN CLOUDS AND RAIN. CIGS NEAR
3 THSD AGL WITH OCCASIONAL MODERATE RAIN THROUGH 11Z...CLOUDS
LIFTING AND RAIN ENDING AFTER 13Z MON.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ020>021.
     FLOOD WATCH FROM MIDNIGHT TONIGHT THROUGH 8 PM MONDAY
     AZZ022>024.

CA...FLOOD WATCH UNTIL 12 PM MONDAY CAZ031>033.

&&

$$

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

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










000
FXUS65 KPSR 020330
AFDPSR

AREA FORECAST DISCUSSION ...CORRECTION
NATIONAL WEATHER SERVICE PHOENIX AZ
830 PM MST SUN MAR 1 2015

...POTENTIAL FOR HEAVY RAIN AFFECTING THE SOUTHWEST AND SOUTH
CENTRAL AZ DESERTS THROUGH LATE MONDAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL EXPAND FROM SOUTHEAST CALIFORNIA INTO
ARIZONA TONIGHT AND SLOWLY SHIFT EASTWARD DURING THE DAY MONDAY.
PERIODS OF MODERATE TO HEAVY RAIN ARE ANTICIPATED...ESPECIALLY OVER
HIGHER TERRAIN AND FOOTHILL LOCATIONS. THERE WILL ALSO BE A SLIGHT
CHANCE OF THUNDERSTORMS DURING THE DAY MONDAY...MAINLY OVER PORTIONS
OF ARIZONA. COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS SYSTEM WITH
BELOW NORMAL READINGS EXPECTED MONDAY THROUGH MID WEEK. A RETURN TO
ABOVE NORMAL TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
THE COLD UPPER TROF THAT HAD BEEN DEVELOPING SLOWLY SOUTH ALONG THE
CENTRAL AND SOUTHERN CA COAST THE PAST 36 HOURS...AND HAS BEEN
SLOWLY CIRCULATING APPRECIABLE AMOUNTS OF LOW LEVEL MOISTURE INTO
THE REGION...HAS BEGUN TO KICK INLAND THIS EVENING. SAT IMAGERY
SHOWED A WELL DEFINED KICKER TROF MOVING RAPIDLY SOUTH THROUGH THE
PACIFIC NORTHWEST UNDER NORTHERLY FLOW ALOFT.

AS A RESULT...REGIONAL UPPER AIR DATA SHOWED A PROFOUNDLY SHARP
BAROCLINIC ZONE ACROSS SOUTHERN CA/SOUTHERN NEVADA THAT HAS BACKED
AND INCREASED THE WINDS ALOFT SINCE MORNING. 700 MB WINDS ALONG THE
COLORADO RIVER WERE NEARLY SOUTH AT 40 KNOTS WHILE 300 MB WINDS WERE
WERE SOUTHWEST 100-120 KNOTS AND DIFLUENT. ALSO...MORE BOUNDARY
LAYER MOISTURE HAS TRANSPORTED NORTH ALONG THE FRONTAL ZONE AND
CURRENTLY FOCUSED IN SOUTHEAST CA/COLORADO RIVER WHERE FAST MOVING
BANDS OF PRECIP HAVE INCREASED THE PAST FEW HOURS.

THEREFORE AS THE COLD DYNAMICAL SYSTEM MOVES INLAND FROM OFFSHORE
SOUTHERN CA/NORTHERN BAJA TONIGHT...AN UPSWING IN PRECIP IS
EXPECTED. PRECIP WILL FOCUS ALONG THE COLORADO RIVER BY MIDNIGHT...
MOVING INTO SOUTHWEST AZ BY 12Z MON...THEN INTO CENTRAL AZ INCLUDING
PHOENIX BY 18Z MON. SINCE SOUTHERLY LOW LEVEL WINDS ARE FAIRLY
STRONG...ENHANCED UPSLOPE PRECIP WILL BE A BIG FACTOR IN THE
POTENTIAL FOR HEAVY RAIN AND RUNOFF. THE FLASH FLOOD WATCH THROUGH
MONDAY...FOCUSED IN THE UPSLOPE AREAS OF SOUTHWEST AND SOUTH CENTRAL
AZ WHERE MOUNTAIN WASHES DRAIN SOUTH INTO THE LOWER DESERTS LOOKS
GOOD FOR NOW.  A QUICK LOOK AT SOME OF THE OFFICE WARM COLLISION
COALESCENCE RAIN STUDIES INDICATE THE POTENTIAL FOR 0.50-0.60 INCHES
ON THE LOWER CENTRAL DESERTS TO NEARLY 2 INCHES IN THE MOUNTAINS AND
FOOTHILLS NORTHWEST THROUGH EAST OF PHOENIX MONDAY.

CURRENT FORECASTS LOOK IN GOOD SHAPE WITH HIGH PRECIP PROBABILITIES
AND THE POTENTIAL FOR HEAVY RAIN. NO UPDATES PLANNED. PREVIOUS
DISCUSSION BELOW STILL APPLIES.



.PREVIOUS DISCUSSION...302 PM MST...

REST OF TODAY THROUGH WEDNESDAY...
SHOWERS HAVE MOVED OVER OUR SOUTHEAST CALIFORNIA ZONES TODAY.
ISOLATED SHOWERS HAVE STARTED TO DEVELOP ELSEWHERE INCLUDING THE
PHOENIX AREA. MADE SOME EARLIER CHANGES TO THE FORECAST TO EXPAND
THE AREAL FLOOD WATCH TO SOUTHEAST CALIFORNIA. THE OTHER MAIN CHANGE
INCLUDED ANOTHER TIMING ADJUSTMENT FOR SOUTH-CENTRAL
ARIZONA...INCLUDING THE PHOENIX AREA...FOR A LATER START AND END. IN
SHORT...ANTICIPATE A SLOW RUNOFF RESPONSE TO THE RAINFALL BUT EXPECT
THERE WILL BE WASHES WITH SUFFICIENT FLOW TO CAUSE DANGEROUS
CONDITIONS AT SOME OF THE UNBRIDGED CROSSINGS. THERE WILL BE SOME
HIGHWAY DIPS AND OTHER LOW LYING AREAS THAT WILL SEE SOME INUNDATION
AS WELL. THE MAIN PRECIP MECHANISMS WITHIN THE LOW PRESSURE SYSTEM
ARE THE FRONTAL ZONE...CURRENTLY EXTENDING SOUTHWESTWARD FROM THE
MOHAVE DESERT...AND DYNAMICAL FORCING FROM SOME DIFFLUENCE RELATED
UPPER LEVEL DIVERGENCE...MAINLY NORTHWEST ARIZONA...AS WELL AS QG
FORCING FROM THE VORTICITY AND WARM AIR ADVECTION. THERE WILL ALSO
BE SOME INFLUENCE FROM THE RIGHT ENTRANCE REGION OF THE JET FOR
TOMORROW. THE FRONT IS ANTICIPATED TO MOVE THROUGH THE PHOENIX AREA
LATE MORNING/MIDDAY WITH PRECIP TRENDING DOWN FROM WEST TO EAST OVER
THE LOWER DESERTS OF ARIZONA IN MONDAY AFTERNOON...CONTINUING HIGHER
TERRAIN. THE MODELS ARE IN GENERALLY GOOD AGREEMENT ON THE TIMING
AND PLACEMENT OF THESE FEATURES THOUGH THE GFS IS A BIT MORE
GENEROUS WITH THE QG FORCING THAN NAM WHILE ECMWF IS A BIT SLOWER
WITH THE ONSET AND DEPARTURE OF PRECIP THAN NAM AND GFS. SEE THE
FLOOD WATCH FOR DETAILS ON THE TIMING AND PRECIP AMOUNTS. THE
UPSTREAM SYSTEM THAT WILL BE HELPING TO MOVE THIS MAIN ONE ALONG IS
CURRENTLY CENTERED NEAR THE ALASKA/CANADA BORDER. IT WILL RAPIDLY
MOVE DOWN THE COAST MONDAY AND THEN INTO NORTHWEST MEXICO TUESDAY.
MEANWHILE ANOTHER SHORT WAVE TRACKS THROUGH THE GREAT BASIN.
OUR FORECAST AREA WILL LARGELY BE BETWEEN THESE FEATURES BUT THEY
WILL CAUSE US TO KEEP A LINGERING SLIGHT CHANCE GOING...MAINLY OVER
SOUTH-CENTRAL ARIZONA. A MUCH WEAKER SHORT WAVE IS ADVERTISED TO
SLIDE DOWN FROM THE NORTH ON WEDNESDAY FOR SLIGHT CHANCES LIMITED TO
THE HIGHER TERRAIN OF SOUTH-CENTRAL AZ. SNOW LEVELS DROP TO NEAR
5000 FEET...INITIALLY OVER SOUTHEAST CALIFORNIA MONDAY MORNING THEN
EASTWARD TO SOUTH-CENTRAL ARIZONA BY EARLY MONDAY EVENING. THE
PRECIP WILL LARGELY BE OVER BY THE TIME THE SNOW LEVELS GET THAT LOW
AND THUS NO NOTABLE ACCUMULATIONS FOR OUR AREA...PERHAPS A DUSTING.
MADE A NUMBER OF TWEAKS TO THE POP/QPF GRIDS BUT NO MAJOR
ALTERATIONS FROM PREVIOUS PACKAGE. AS FOR TEMPERATURES...ANTICIPATE
LITTLE CHANGE OVER SOUTHEAST CALIFORNIA MONDAY SINCE THEY HAVE
ALREADY BEEN GETTING PRECIP. IT WILL BE MUCH COOLER THOUGH EAST OF
THE LOWER COLORADO RIVER VALLEY...ESPECIALLY SOUTH-CENTRAL ARIZONA.
IN FACT...PHOENIX AREA HIGH TEMP MONDAY MAY OCCUR BEFORE SUNRISE
WITH AFTERNOON PEAK IN THE 50S. WITH THE FOLLOW ON DISTURBANCES
TUESDAY AND WEDNESDAY...TEMPS WILL BE SLOW TO WARM UP THE FIRST HALF
OF THE WEEK.

FROM MID-WEEK ONWARD...RIDGING WILL TAKE HOLD ACROSS THE REGION AND
CONSEQUENTLY TEMPERATURES WILL ALSO CLIMB BACK ABOVE NORMAL BY LATE
WEEK INTO THE WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
A MOIST COLD FRONT APPROACHING FOR MONDAY MORNING. CLOUDS AND
SHOWERS WILL SLOWLY INCREASE AFTER 08Z MON...REACHING A PEAK AROUND
18Z MON. AS A RESULT...BKN CLDS BETWEEN 6-8 THSD AGL THROUGH 15Z
MON...THEN LOWERING TO NEAR 2 THSD BKN IN MODERATE RAIN AT TIMES
BETWEEN 15Z AND 21Z MON. SOUTH WIND 6 TO 8 KNOTS...BECOMING GUSTY
NEAR 20 KNOTS AROUND 17Z WITH SHOWERS.


SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
A MOIST COLD FRONT MOVING THROUGH THE AREA BETWEEN 07Z-12Z MON.  AS
A RESULT...OCCASIONAL MVFR CONDITIONS IN CLOUDS AND RAIN. CIGS NEAR
3 THSD AGL WITH OCCASIONAL MODERATE RAIN THROUGH 11Z...CLOUDS
LIFTING AND RAIN ENDING AFTER 13Z MON.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ020>021.
     FLOOD WATCH FROM MIDNIGHT TONIGHT THROUGH 8 PM MONDAY
     AZZ022>024.

CA...FLOOD WATCH UNTIL 12 PM MONDAY CAZ031>033.

&&

$$

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

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











000
FXUS65 KPSR 020322
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
820 PM MST SUN MAR 1 2015

...POTENTIAL FOR HEAVY RAIN AFFECTING THE SOUTHWEST AND SOUTH
CENTRAL AZ DESERTS THROUGH LATE MONDAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL EXPAND FROM SOUTHEAST CALIFORNIA INTO
ARIZONA TONIGHT AND SLOWLY SHIFT EASTWARD DURING THE DAY MONDAY.
PERIODS OF MODERATE TO HEAVY RAIN ARE ANTICIPATED...ESPECIALLY OVER
HIGHER TERRAIN AND FOOTHILL LOCATIONS. THERE WILL ALSO BE A SLIGHT
CHANCE OF THUNDERSTORMS DURING THE DAY MONDAY...MAINLY OVER PORTIONS
OF ARIZONA. COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS SYSTEM WITH
BELOW NORMAL READINGS EXPECTED MONDAY THROUGH MID WEEK. A RETURN TO
ABOVE NORMAL TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
THE COLD UPPER TROF THAT HAD BEEN DEVELOPING SLOWLY SOUTH ALONG THE
CENTRAL AND SOUTHERN CA COAST THE PAST 36 HOURS...AND HAS BEEN
SLOWLY CIRCULATING APPRECIABLE AMOUNTS OF LOW LEVEL MOISTURE INTO
THE REGION...HAS BEGUN TO KICK INLAND THIS EVENING. SAT IMAGERY
SHOWED A WELL DEFINED KICKER TROF MOVING RAPIDLY SOUTH THROUGH THE
PACIFIC NORTHWEST UNDER NORTHERLY FLOW ALOFT.

AS A RESULT...REGIONAL UPPER AIR DATA SHOWED A PROFOUNDLY SHARP
BAROCLINIC ZONE ACROSS SOUTHERN CA/SOUTHERN NEVADA THAT HAS BACKED
AND INCREASED THE WINDS ALOFT SINCE MORNING. 700 MB WINDS ALONG THE
COLORADO RIVER WERE NEARLY SOUTH AT 40 KNOTS WHILE 300 MB WINDS WERE
WERE SOUTHWEST 100-120 KNOTS AND DIFLUENT. ALSO...MORE BOUNDARY
LAYER MOISTURE HAS TRANSPORTED NORTH ALONG THE FRONTAL ZONE AND
CURRENTLY FOCUSED IN SOUTHEAST CA/COLORADO RIVER WHERE FAST MOVING
BANDS OF PRECIP HAVE INCREASED THE PAST FEW HOURS.

THEREFORE AS THE COLD DYNAMICAL SYSTEM MOVES INLAND FROM OFFSHORE
SOUTHERN CA/NORTHERN BAJA TONIGHT...AN UPSWING IN PRECIP IS
EXPECTED. PRECIP WILL FOCUS ALONG THE COLORADO RIVER BY MIDNIGHT...
MOVING INTO SOUTHWEST AZ BY 12Z MON...THEN INTO CENTRAL AZ INCLUDING
PHOENIX BY 18Z MON. SINCE SOUTHERLY LOW LEVEL WINDS ARE FAIRLY
STRONG...ENHANCED UPSLOPE PRECIP WILL BE A BIG FACTOR IN THE
POTENTIAL FOR HEAVY RAIN AND RUNOFF. THE FLASH FLOOD WATCH THROUGH
MONDAY...FOCUSED IN THE UPSLOPE AREAS OF SOUTHWEST AND SOUTH CENTRAL
AZ WHERE MOUNTAIN WASHES DRAIN SOUTH INTO THE LOWER DESERTS LOOKS
GOOD FOR NOW.  A QUICK LOOK AT SOME OF THE OFFICE WARM COLLISION
COALESCENCE RAIN STUDIES INDICATE THE POTENTIAL FOR 0.50-0.60 INCHES
ON THE LOWER CENTRAL DESERTS TO NEARLY 2 INCHES IN THE MOUNTAINS AND
FOOTHILLS NORTHWEST THROUGH EAST OF PHOENIX MONDAY.

CURRENT FORECASTS LOOK IN GOOD SHAPE WITH HIGH PRECIP PROBABILITIES
AND THE POTENTIAL FOR HEAVY RAIN. NO UPDATES PLANNED. PREVIOUS
DISCUSSION BELOW STILL APPLIES.



.PREVIOUS DISCUSSION...302 PM MST...

REST OF TODAY THROUGH WEDNESDAY...
SHOWERS HAVE MOVED OVER OUR SOUTHEAST CALIFORNIA ZONES TODAY.
ISOLATED SHOWERS HAVE STARTED TO DEVELOP ELSEWHERE INCLUDING THE
PHOENIX AREA. MADE SOME EARLIER CHANGES TO THE FORECAST TO EXPAND
THE AREAL FLOOD WATCH TO SOUTHEAST CALIFORNIA. THE OTHER MAIN CHANGE
INCLUDED ANOTHER TIMING ADJUSTMENT FOR SOUTH-CENTRAL
ARIZONA...INCLUDING THE PHOENIX AREA...FOR A LATER START AND END. IN
SHORT...ANTICIPATE A SLOW RUNOFF RESPONSE TO THE RAINFALL BUT EXPECT
THERE WILL BE WASHES WITH SUFFICIENT FLOW TO CAUSE DANGEROUS
CONDITIONS AT SOME OF THE UNBRIDGED CROSSINGS. THERE WILL BE SOME
HIGHWAY DIPS AND OTHER LOW LYING AREAS THAT WILL SEE SOME INUNDATION
AS WELL. THE MAIN PRECIP MECHANISMS WITHIN THE LOW PRESSURE SYSTEM
ARE THE FRONTAL ZONE...CURRENTLY EXTENDING SOUTHWESTWARD FROM THE
MOHAVE DESERT...AND DYNAMICAL FORCING FROM SOME DIFFLUENCE RELATED
UPPER LEVEL DIVERGENCE...MAINLY NORTHWEST ARIZONA...AS WELL AS QG
FORCING FROM THE VORTICITY AND WARM AIR ADVECTION. THERE WILL ALSO
BE SOME INFLUENCE FROM THE RIGHT ENTRANCE REGION OF THE JET FOR
TOMORROW. THE FRONT IS ANTICIPATED TO MOVE THROUGH THE PHOENIX AREA
LATE MORNING/MIDDAY WITH PRECIP TRENDING DOWN FROM WEST TO EAST OVER
THE LOWER DESERTS OF ARIZONA IN MONDAY AFTERNOON...CONTINUING HIGHER
TERRAIN. THE MODELS ARE IN GENERALLY GOOD AGREEMENT ON THE TIMING
AND PLACEMENT OF THESE FEATURES THOUGH THE GFS IS A BIT MORE
GENEROUS WITH THE QG FORCING THAN NAM WHILE ECMWF IS A BIT SLOWER
WITH THE ONSET AND DEPARTURE OF PRECIP THAN NAM AND GFS. SEE THE
FLOOD WATCH FOR DETAILS ON THE TIMING AND PRECIP AMOUNTS. THE
UPSTREAM SYSTEM THAT WILL BE HELPING TO MOVE THIS MAIN ONE ALONG IS
CURRENTLY CENTERED NEAR THE ALASKA/CANADA BORDER. IT WILL RAPIDLY
MOVE DOWN THE COAST MONDAY AND THEN INTO NORTHWEST MEXICO TUESDAY.
MEANWHILE ANOTHER SHORT WAVE TRACKS THROUGH THE GREAT BASIN.
OUR FORECAST AREA WILL LARGELY BE BETWEEN THESE FEATURES BUT THEY
WILL CAUSE US TO KEEP A LINGERING SLIGHT CHANCE GOING...MAINLY OVER
SOUTH-CENTRAL ARIZONA. A MUCH WEAKER SHORT WAVE IS ADVERTISED TO
SLIDE DOWN FROM THE NORTH ON WEDNESDAY FOR SLIGHT CHANCES LIMITED TO
THE HIGHER TERRAIN OF SOUTH-CENTRAL AZ. SNOW LEVELS DROP TO NEAR
5000 FEET...INITIALLY OVER SOUTHEAST CALIFORNIA MONDAY MORNING THEN
EASTWARD TO SOUTH-CENTRAL ARIZONA BY EARLY MONDAY EVENING. THE
PRECIP WILL LARGELY BE OVER BY THE TIME THE SNOW LEVELS GET THAT LOW
AND THUS NO NOTABLE ACCUMULATIONS FOR OUR AREA...PERHAPS A DUSTING.
MADE A NUMBER OF TWEAKS TO THE POP/QPF GRIDS BUT NO MAJOR
ALTERATIONS FROM PREVIOUS PACKAGE. AS FOR TEMPERATURES...ANTICIPATE
LITTLE CHANGE OVER SOUTHEAST CALIFORNIA MONDAY SINCE THEY HAVE
ALREADY BEEN GETTING PRECIP. IT WILL BE MUCH COOLER THOUGH EAST OF
THE LOWER COLORADO RIVER VALLEY...ESPECIALLY SOUTH-CENTRAL ARIZONA.
IN FACT...PHOENIX AREA HIGH TEMP MONDAY MAY OCCUR BEFORE SUNRISE
WITH AFTERNOON PEAK IN THE 50S. WITH THE FOLLOW ON DISTURBANCES
TUESDAY AND WEDNESDAY...TEMPS WILL BE SLOW TO WARM UP THE FIRST HALF
OF THE WEEK.

FROM MID-WEEK ONWARD...RIDGING WILL TAKE HOLD ACROSS THE REGION AND
CONSEQUENTLY TEMPERATURES WILL ALSO CLIMB BACK ABOVE NORMAL BY LATE
WEEK INTO THE WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
AHEAD OF AN APPROACHING COLD FRONT AND UPPER LOW...MOSTLY BROKEN
SKIES AND ISOLATED POP-UP SHOWERS WILL CONTINUE FOR THE PHX AREA
TERMINALS INTO THIS EVENING. CIGS WILL VARY BETWEEN 5-7KFT OR
SO...SAVE FOR ANY BRIEF LOWERING IF A STRAY SHOWER PASSES OVER THE
TERMINAL. FEEL THE SHOWER COVERAGE SHOULD BE SPARSE ENOUGH THROUGH
THE EVENING THAT VCSH MENTION IS WARRANTED FOR KSDL...LESS SO FOR
KPHX AND KIWA. SURFACE WINDS WILL CONTINUE IN A SOUTH TO SLIGHT
SOUTHEASTERLY ATTITUDE WITH A BRIEF PERIOD OF SOUTHWESTERLY LATER IN
THE AFTERNOON...WITH PERIODIC GUSTS IN THE 20KT RANGE. LONG AWAITED
COLD-FRONT AND PRECIP BAND WILL MOVE IN FROM THE WEST
OVERNIGHT...INCREASING SHOWER COVERAGE MOSTLY AFTER 02/07Z AND
BLOSSOMING INTO AREAS OF MODERATE AND PERSISTENT RAINFALL MONDAY
MORNING...CLOSER TOWARDS 02/13-14Z. INTRODUCED MVFR CIGS AND LOWERED
VSBYS TOWARDS THE END OF THE 01/18Z TAFS. CONFIDENCE IS HIGH FOR THE
SEVERAL HOURS/ROUNDS OF RAINFALL IN THE AM AND MEDIUM FOR THE CIGS
HEIGHTS ATTM. EXPECT WITH THE AMPLE AMOUNT OF LOW LEVEL MOISTURE AND
RAINFALL...TERRAIN OBSCURATIONS WILL BE WIDESPREAD ACROSS THE PHX
METRO THROUGH PORTIONS MONDAY.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
BROAD BAND OF PRECIPITATION WILL CONTINUE TO STRETCH ACROSS
SOUTHEAST CA...FROM KIPL THROUGH KBLH...THROUGH THIS EVENING. LOW
END VFR AND MVFR CIGS WILL RESULT...WITH EVEN SOME SCUD/MIST FEW/SCT
DEVELOPMENT FEW HUNDRED FEET OFF THE SURFACE. PERIODS OF
MODERATE...TO AT TIMES HEAVY...RAINFALL WILL CONTINUE TO MOVE
SOUTHWEST TO NORTHEAST ACROSS THE AREA THROUGH THE EVENING...BEFORE
GRADUALLY TAPERING OFF IN COVERAGE AFTER 02/08-09Z. SURFACE WINDS
WILL CONTINUE TO BE ON THE LIGHT SIDE...ATTEMPT SOME WEST TO
NORTHWEST HEADINGS...OTHERWISE REMAIN VARIABLE. RAIN SHOWER COVERAGE
WILL THIN TOWARDS THE MORNING...BUT WITH STILL ENOUGH COVERAGE TO
WARRANT VCSH MENTION. FAIRLY DECENT RAINFALL ACCUMULATIONS ARE
EXPECTED...WHICH WILL LEAD TO PONDING OF WATER ON APRON AND RUNWAY
SURFACES INTO MONDAY.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ020>021.
     FLOOD WATCH FROM MIDNIGHT TONIGHT THROUGH 8 PM MONDAY
     AZZ022>024.

CA...FLOOD WATCH UNTIL 12 PM MONDAY CAZ031>033.

&&

$$

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

DISCUSSION...AJ/LEINS
AVIATION...NOLTE
FIRE WEATHER...KUHLMAN







000
FXUS65 KPSR 020322
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
820 PM MST SUN MAR 1 2015

...POTENTIAL FOR HEAVY RAIN AFFECTING THE SOUTHWEST AND SOUTH
CENTRAL AZ DESERTS THROUGH LATE MONDAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL EXPAND FROM SOUTHEAST CALIFORNIA INTO
ARIZONA TONIGHT AND SLOWLY SHIFT EASTWARD DURING THE DAY MONDAY.
PERIODS OF MODERATE TO HEAVY RAIN ARE ANTICIPATED...ESPECIALLY OVER
HIGHER TERRAIN AND FOOTHILL LOCATIONS. THERE WILL ALSO BE A SLIGHT
CHANCE OF THUNDERSTORMS DURING THE DAY MONDAY...MAINLY OVER PORTIONS
OF ARIZONA. COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS SYSTEM WITH
BELOW NORMAL READINGS EXPECTED MONDAY THROUGH MID WEEK. A RETURN TO
ABOVE NORMAL TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
THE COLD UPPER TROF THAT HAD BEEN DEVELOPING SLOWLY SOUTH ALONG THE
CENTRAL AND SOUTHERN CA COAST THE PAST 36 HOURS...AND HAS BEEN
SLOWLY CIRCULATING APPRECIABLE AMOUNTS OF LOW LEVEL MOISTURE INTO
THE REGION...HAS BEGUN TO KICK INLAND THIS EVENING. SAT IMAGERY
SHOWED A WELL DEFINED KICKER TROF MOVING RAPIDLY SOUTH THROUGH THE
PACIFIC NORTHWEST UNDER NORTHERLY FLOW ALOFT.

AS A RESULT...REGIONAL UPPER AIR DATA SHOWED A PROFOUNDLY SHARP
BAROCLINIC ZONE ACROSS SOUTHERN CA/SOUTHERN NEVADA THAT HAS BACKED
AND INCREASED THE WINDS ALOFT SINCE MORNING. 700 MB WINDS ALONG THE
COLORADO RIVER WERE NEARLY SOUTH AT 40 KNOTS WHILE 300 MB WINDS WERE
WERE SOUTHWEST 100-120 KNOTS AND DIFLUENT. ALSO...MORE BOUNDARY
LAYER MOISTURE HAS TRANSPORTED NORTH ALONG THE FRONTAL ZONE AND
CURRENTLY FOCUSED IN SOUTHEAST CA/COLORADO RIVER WHERE FAST MOVING
BANDS OF PRECIP HAVE INCREASED THE PAST FEW HOURS.

THEREFORE AS THE COLD DYNAMICAL SYSTEM MOVES INLAND FROM OFFSHORE
SOUTHERN CA/NORTHERN BAJA TONIGHT...AN UPSWING IN PRECIP IS
EXPECTED. PRECIP WILL FOCUS ALONG THE COLORADO RIVER BY MIDNIGHT...
MOVING INTO SOUTHWEST AZ BY 12Z MON...THEN INTO CENTRAL AZ INCLUDING
PHOENIX BY 18Z MON. SINCE SOUTHERLY LOW LEVEL WINDS ARE FAIRLY
STRONG...ENHANCED UPSLOPE PRECIP WILL BE A BIG FACTOR IN THE
POTENTIAL FOR HEAVY RAIN AND RUNOFF. THE FLASH FLOOD WATCH THROUGH
MONDAY...FOCUSED IN THE UPSLOPE AREAS OF SOUTHWEST AND SOUTH CENTRAL
AZ WHERE MOUNTAIN WASHES DRAIN SOUTH INTO THE LOWER DESERTS LOOKS
GOOD FOR NOW.  A QUICK LOOK AT SOME OF THE OFFICE WARM COLLISION
COALESCENCE RAIN STUDIES INDICATE THE POTENTIAL FOR 0.50-0.60 INCHES
ON THE LOWER CENTRAL DESERTS TO NEARLY 2 INCHES IN THE MOUNTAINS AND
FOOTHILLS NORTHWEST THROUGH EAST OF PHOENIX MONDAY.

CURRENT FORECASTS LOOK IN GOOD SHAPE WITH HIGH PRECIP PROBABILITIES
AND THE POTENTIAL FOR HEAVY RAIN. NO UPDATES PLANNED. PREVIOUS
DISCUSSION BELOW STILL APPLIES.



.PREVIOUS DISCUSSION...302 PM MST...

REST OF TODAY THROUGH WEDNESDAY...
SHOWERS HAVE MOVED OVER OUR SOUTHEAST CALIFORNIA ZONES TODAY.
ISOLATED SHOWERS HAVE STARTED TO DEVELOP ELSEWHERE INCLUDING THE
PHOENIX AREA. MADE SOME EARLIER CHANGES TO THE FORECAST TO EXPAND
THE AREAL FLOOD WATCH TO SOUTHEAST CALIFORNIA. THE OTHER MAIN CHANGE
INCLUDED ANOTHER TIMING ADJUSTMENT FOR SOUTH-CENTRAL
ARIZONA...INCLUDING THE PHOENIX AREA...FOR A LATER START AND END. IN
SHORT...ANTICIPATE A SLOW RUNOFF RESPONSE TO THE RAINFALL BUT EXPECT
THERE WILL BE WASHES WITH SUFFICIENT FLOW TO CAUSE DANGEROUS
CONDITIONS AT SOME OF THE UNBRIDGED CROSSINGS. THERE WILL BE SOME
HIGHWAY DIPS AND OTHER LOW LYING AREAS THAT WILL SEE SOME INUNDATION
AS WELL. THE MAIN PRECIP MECHANISMS WITHIN THE LOW PRESSURE SYSTEM
ARE THE FRONTAL ZONE...CURRENTLY EXTENDING SOUTHWESTWARD FROM THE
MOHAVE DESERT...AND DYNAMICAL FORCING FROM SOME DIFFLUENCE RELATED
UPPER LEVEL DIVERGENCE...MAINLY NORTHWEST ARIZONA...AS WELL AS QG
FORCING FROM THE VORTICITY AND WARM AIR ADVECTION. THERE WILL ALSO
BE SOME INFLUENCE FROM THE RIGHT ENTRANCE REGION OF THE JET FOR
TOMORROW. THE FRONT IS ANTICIPATED TO MOVE THROUGH THE PHOENIX AREA
LATE MORNING/MIDDAY WITH PRECIP TRENDING DOWN FROM WEST TO EAST OVER
THE LOWER DESERTS OF ARIZONA IN MONDAY AFTERNOON...CONTINUING HIGHER
TERRAIN. THE MODELS ARE IN GENERALLY GOOD AGREEMENT ON THE TIMING
AND PLACEMENT OF THESE FEATURES THOUGH THE GFS IS A BIT MORE
GENEROUS WITH THE QG FORCING THAN NAM WHILE ECMWF IS A BIT SLOWER
WITH THE ONSET AND DEPARTURE OF PRECIP THAN NAM AND GFS. SEE THE
FLOOD WATCH FOR DETAILS ON THE TIMING AND PRECIP AMOUNTS. THE
UPSTREAM SYSTEM THAT WILL BE HELPING TO MOVE THIS MAIN ONE ALONG IS
CURRENTLY CENTERED NEAR THE ALASKA/CANADA BORDER. IT WILL RAPIDLY
MOVE DOWN THE COAST MONDAY AND THEN INTO NORTHWEST MEXICO TUESDAY.
MEANWHILE ANOTHER SHORT WAVE TRACKS THROUGH THE GREAT BASIN.
OUR FORECAST AREA WILL LARGELY BE BETWEEN THESE FEATURES BUT THEY
WILL CAUSE US TO KEEP A LINGERING SLIGHT CHANCE GOING...MAINLY OVER
SOUTH-CENTRAL ARIZONA. A MUCH WEAKER SHORT WAVE IS ADVERTISED TO
SLIDE DOWN FROM THE NORTH ON WEDNESDAY FOR SLIGHT CHANCES LIMITED TO
THE HIGHER TERRAIN OF SOUTH-CENTRAL AZ. SNOW LEVELS DROP TO NEAR
5000 FEET...INITIALLY OVER SOUTHEAST CALIFORNIA MONDAY MORNING THEN
EASTWARD TO SOUTH-CENTRAL ARIZONA BY EARLY MONDAY EVENING. THE
PRECIP WILL LARGELY BE OVER BY THE TIME THE SNOW LEVELS GET THAT LOW
AND THUS NO NOTABLE ACCUMULATIONS FOR OUR AREA...PERHAPS A DUSTING.
MADE A NUMBER OF TWEAKS TO THE POP/QPF GRIDS BUT NO MAJOR
ALTERATIONS FROM PREVIOUS PACKAGE. AS FOR TEMPERATURES...ANTICIPATE
LITTLE CHANGE OVER SOUTHEAST CALIFORNIA MONDAY SINCE THEY HAVE
ALREADY BEEN GETTING PRECIP. IT WILL BE MUCH COOLER THOUGH EAST OF
THE LOWER COLORADO RIVER VALLEY...ESPECIALLY SOUTH-CENTRAL ARIZONA.
IN FACT...PHOENIX AREA HIGH TEMP MONDAY MAY OCCUR BEFORE SUNRISE
WITH AFTERNOON PEAK IN THE 50S. WITH THE FOLLOW ON DISTURBANCES
TUESDAY AND WEDNESDAY...TEMPS WILL BE SLOW TO WARM UP THE FIRST HALF
OF THE WEEK.

FROM MID-WEEK ONWARD...RIDGING WILL TAKE HOLD ACROSS THE REGION AND
CONSEQUENTLY TEMPERATURES WILL ALSO CLIMB BACK ABOVE NORMAL BY LATE
WEEK INTO THE WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
AHEAD OF AN APPROACHING COLD FRONT AND UPPER LOW...MOSTLY BROKEN
SKIES AND ISOLATED POP-UP SHOWERS WILL CONTINUE FOR THE PHX AREA
TERMINALS INTO THIS EVENING. CIGS WILL VARY BETWEEN 5-7KFT OR
SO...SAVE FOR ANY BRIEF LOWERING IF A STRAY SHOWER PASSES OVER THE
TERMINAL. FEEL THE SHOWER COVERAGE SHOULD BE SPARSE ENOUGH THROUGH
THE EVENING THAT VCSH MENTION IS WARRANTED FOR KSDL...LESS SO FOR
KPHX AND KIWA. SURFACE WINDS WILL CONTINUE IN A SOUTH TO SLIGHT
SOUTHEASTERLY ATTITUDE WITH A BRIEF PERIOD OF SOUTHWESTERLY LATER IN
THE AFTERNOON...WITH PERIODIC GUSTS IN THE 20KT RANGE. LONG AWAITED
COLD-FRONT AND PRECIP BAND WILL MOVE IN FROM THE WEST
OVERNIGHT...INCREASING SHOWER COVERAGE MOSTLY AFTER 02/07Z AND
BLOSSOMING INTO AREAS OF MODERATE AND PERSISTENT RAINFALL MONDAY
MORNING...CLOSER TOWARDS 02/13-14Z. INTRODUCED MVFR CIGS AND LOWERED
VSBYS TOWARDS THE END OF THE 01/18Z TAFS. CONFIDENCE IS HIGH FOR THE
SEVERAL HOURS/ROUNDS OF RAINFALL IN THE AM AND MEDIUM FOR THE CIGS
HEIGHTS ATTM. EXPECT WITH THE AMPLE AMOUNT OF LOW LEVEL MOISTURE AND
RAINFALL...TERRAIN OBSCURATIONS WILL BE WIDESPREAD ACROSS THE PHX
METRO THROUGH PORTIONS MONDAY.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
BROAD BAND OF PRECIPITATION WILL CONTINUE TO STRETCH ACROSS
SOUTHEAST CA...FROM KIPL THROUGH KBLH...THROUGH THIS EVENING. LOW
END VFR AND MVFR CIGS WILL RESULT...WITH EVEN SOME SCUD/MIST FEW/SCT
DEVELOPMENT FEW HUNDRED FEET OFF THE SURFACE. PERIODS OF
MODERATE...TO AT TIMES HEAVY...RAINFALL WILL CONTINUE TO MOVE
SOUTHWEST TO NORTHEAST ACROSS THE AREA THROUGH THE EVENING...BEFORE
GRADUALLY TAPERING OFF IN COVERAGE AFTER 02/08-09Z. SURFACE WINDS
WILL CONTINUE TO BE ON THE LIGHT SIDE...ATTEMPT SOME WEST TO
NORTHWEST HEADINGS...OTHERWISE REMAIN VARIABLE. RAIN SHOWER COVERAGE
WILL THIN TOWARDS THE MORNING...BUT WITH STILL ENOUGH COVERAGE TO
WARRANT VCSH MENTION. FAIRLY DECENT RAINFALL ACCUMULATIONS ARE
EXPECTED...WHICH WILL LEAD TO PONDING OF WATER ON APRON AND RUNWAY
SURFACES INTO MONDAY.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ020>021.
     FLOOD WATCH FROM MIDNIGHT TONIGHT THROUGH 8 PM MONDAY
     AZZ022>024.

CA...FLOOD WATCH UNTIL 12 PM MONDAY CAZ031>033.

&&

$$

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

DISCUSSION...AJ/LEINS
AVIATION...NOLTE
FIRE WEATHER...KUHLMAN








000
FXUS65 KPSR 020322
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
820 PM MST SUN MAR 1 2015

...POTENTIAL FOR HEAVY RAIN AFFECTING THE SOUTHWEST AND SOUTH
CENTRAL AZ DESERTS THROUGH LATE MONDAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL EXPAND FROM SOUTHEAST CALIFORNIA INTO
ARIZONA TONIGHT AND SLOWLY SHIFT EASTWARD DURING THE DAY MONDAY.
PERIODS OF MODERATE TO HEAVY RAIN ARE ANTICIPATED...ESPECIALLY OVER
HIGHER TERRAIN AND FOOTHILL LOCATIONS. THERE WILL ALSO BE A SLIGHT
CHANCE OF THUNDERSTORMS DURING THE DAY MONDAY...MAINLY OVER PORTIONS
OF ARIZONA. COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS SYSTEM WITH
BELOW NORMAL READINGS EXPECTED MONDAY THROUGH MID WEEK. A RETURN TO
ABOVE NORMAL TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
THE COLD UPPER TROF THAT HAD BEEN DEVELOPING SLOWLY SOUTH ALONG THE
CENTRAL AND SOUTHERN CA COAST THE PAST 36 HOURS...AND HAS BEEN
SLOWLY CIRCULATING APPRECIABLE AMOUNTS OF LOW LEVEL MOISTURE INTO
THE REGION...HAS BEGUN TO KICK INLAND THIS EVENING. SAT IMAGERY
SHOWED A WELL DEFINED KICKER TROF MOVING RAPIDLY SOUTH THROUGH THE
PACIFIC NORTHWEST UNDER NORTHERLY FLOW ALOFT.

AS A RESULT...REGIONAL UPPER AIR DATA SHOWED A PROFOUNDLY SHARP
BAROCLINIC ZONE ACROSS SOUTHERN CA/SOUTHERN NEVADA THAT HAS BACKED
AND INCREASED THE WINDS ALOFT SINCE MORNING. 700 MB WINDS ALONG THE
COLORADO RIVER WERE NEARLY SOUTH AT 40 KNOTS WHILE 300 MB WINDS WERE
WERE SOUTHWEST 100-120 KNOTS AND DIFLUENT. ALSO...MORE BOUNDARY
LAYER MOISTURE HAS TRANSPORTED NORTH ALONG THE FRONTAL ZONE AND
CURRENTLY FOCUSED IN SOUTHEAST CA/COLORADO RIVER WHERE FAST MOVING
BANDS OF PRECIP HAVE INCREASED THE PAST FEW HOURS.

THEREFORE AS THE COLD DYNAMICAL SYSTEM MOVES INLAND FROM OFFSHORE
SOUTHERN CA/NORTHERN BAJA TONIGHT...AN UPSWING IN PRECIP IS
EXPECTED. PRECIP WILL FOCUS ALONG THE COLORADO RIVER BY MIDNIGHT...
MOVING INTO SOUTHWEST AZ BY 12Z MON...THEN INTO CENTRAL AZ INCLUDING
PHOENIX BY 18Z MON. SINCE SOUTHERLY LOW LEVEL WINDS ARE FAIRLY
STRONG...ENHANCED UPSLOPE PRECIP WILL BE A BIG FACTOR IN THE
POTENTIAL FOR HEAVY RAIN AND RUNOFF. THE FLASH FLOOD WATCH THROUGH
MONDAY...FOCUSED IN THE UPSLOPE AREAS OF SOUTHWEST AND SOUTH CENTRAL
AZ WHERE MOUNTAIN WASHES DRAIN SOUTH INTO THE LOWER DESERTS LOOKS
GOOD FOR NOW.  A QUICK LOOK AT SOME OF THE OFFICE WARM COLLISION
COALESCENCE RAIN STUDIES INDICATE THE POTENTIAL FOR 0.50-0.60 INCHES
ON THE LOWER CENTRAL DESERTS TO NEARLY 2 INCHES IN THE MOUNTAINS AND
FOOTHILLS NORTHWEST THROUGH EAST OF PHOENIX MONDAY.

CURRENT FORECASTS LOOK IN GOOD SHAPE WITH HIGH PRECIP PROBABILITIES
AND THE POTENTIAL FOR HEAVY RAIN. NO UPDATES PLANNED. PREVIOUS
DISCUSSION BELOW STILL APPLIES.



.PREVIOUS DISCUSSION...302 PM MST...

REST OF TODAY THROUGH WEDNESDAY...
SHOWERS HAVE MOVED OVER OUR SOUTHEAST CALIFORNIA ZONES TODAY.
ISOLATED SHOWERS HAVE STARTED TO DEVELOP ELSEWHERE INCLUDING THE
PHOENIX AREA. MADE SOME EARLIER CHANGES TO THE FORECAST TO EXPAND
THE AREAL FLOOD WATCH TO SOUTHEAST CALIFORNIA. THE OTHER MAIN CHANGE
INCLUDED ANOTHER TIMING ADJUSTMENT FOR SOUTH-CENTRAL
ARIZONA...INCLUDING THE PHOENIX AREA...FOR A LATER START AND END. IN
SHORT...ANTICIPATE A SLOW RUNOFF RESPONSE TO THE RAINFALL BUT EXPECT
THERE WILL BE WASHES WITH SUFFICIENT FLOW TO CAUSE DANGEROUS
CONDITIONS AT SOME OF THE UNBRIDGED CROSSINGS. THERE WILL BE SOME
HIGHWAY DIPS AND OTHER LOW LYING AREAS THAT WILL SEE SOME INUNDATION
AS WELL. THE MAIN PRECIP MECHANISMS WITHIN THE LOW PRESSURE SYSTEM
ARE THE FRONTAL ZONE...CURRENTLY EXTENDING SOUTHWESTWARD FROM THE
MOHAVE DESERT...AND DYNAMICAL FORCING FROM SOME DIFFLUENCE RELATED
UPPER LEVEL DIVERGENCE...MAINLY NORTHWEST ARIZONA...AS WELL AS QG
FORCING FROM THE VORTICITY AND WARM AIR ADVECTION. THERE WILL ALSO
BE SOME INFLUENCE FROM THE RIGHT ENTRANCE REGION OF THE JET FOR
TOMORROW. THE FRONT IS ANTICIPATED TO MOVE THROUGH THE PHOENIX AREA
LATE MORNING/MIDDAY WITH PRECIP TRENDING DOWN FROM WEST TO EAST OVER
THE LOWER DESERTS OF ARIZONA IN MONDAY AFTERNOON...CONTINUING HIGHER
TERRAIN. THE MODELS ARE IN GENERALLY GOOD AGREEMENT ON THE TIMING
AND PLACEMENT OF THESE FEATURES THOUGH THE GFS IS A BIT MORE
GENEROUS WITH THE QG FORCING THAN NAM WHILE ECMWF IS A BIT SLOWER
WITH THE ONSET AND DEPARTURE OF PRECIP THAN NAM AND GFS. SEE THE
FLOOD WATCH FOR DETAILS ON THE TIMING AND PRECIP AMOUNTS. THE
UPSTREAM SYSTEM THAT WILL BE HELPING TO MOVE THIS MAIN ONE ALONG IS
CURRENTLY CENTERED NEAR THE ALASKA/CANADA BORDER. IT WILL RAPIDLY
MOVE DOWN THE COAST MONDAY AND THEN INTO NORTHWEST MEXICO TUESDAY.
MEANWHILE ANOTHER SHORT WAVE TRACKS THROUGH THE GREAT BASIN.
OUR FORECAST AREA WILL LARGELY BE BETWEEN THESE FEATURES BUT THEY
WILL CAUSE US TO KEEP A LINGERING SLIGHT CHANCE GOING...MAINLY OVER
SOUTH-CENTRAL ARIZONA. A MUCH WEAKER SHORT WAVE IS ADVERTISED TO
SLIDE DOWN FROM THE NORTH ON WEDNESDAY FOR SLIGHT CHANCES LIMITED TO
THE HIGHER TERRAIN OF SOUTH-CENTRAL AZ. SNOW LEVELS DROP TO NEAR
5000 FEET...INITIALLY OVER SOUTHEAST CALIFORNIA MONDAY MORNING THEN
EASTWARD TO SOUTH-CENTRAL ARIZONA BY EARLY MONDAY EVENING. THE
PRECIP WILL LARGELY BE OVER BY THE TIME THE SNOW LEVELS GET THAT LOW
AND THUS NO NOTABLE ACCUMULATIONS FOR OUR AREA...PERHAPS A DUSTING.
MADE A NUMBER OF TWEAKS TO THE POP/QPF GRIDS BUT NO MAJOR
ALTERATIONS FROM PREVIOUS PACKAGE. AS FOR TEMPERATURES...ANTICIPATE
LITTLE CHANGE OVER SOUTHEAST CALIFORNIA MONDAY SINCE THEY HAVE
ALREADY BEEN GETTING PRECIP. IT WILL BE MUCH COOLER THOUGH EAST OF
THE LOWER COLORADO RIVER VALLEY...ESPECIALLY SOUTH-CENTRAL ARIZONA.
IN FACT...PHOENIX AREA HIGH TEMP MONDAY MAY OCCUR BEFORE SUNRISE
WITH AFTERNOON PEAK IN THE 50S. WITH THE FOLLOW ON DISTURBANCES
TUESDAY AND WEDNESDAY...TEMPS WILL BE SLOW TO WARM UP THE FIRST HALF
OF THE WEEK.

FROM MID-WEEK ONWARD...RIDGING WILL TAKE HOLD ACROSS THE REGION AND
CONSEQUENTLY TEMPERATURES WILL ALSO CLIMB BACK ABOVE NORMAL BY LATE
WEEK INTO THE WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
AHEAD OF AN APPROACHING COLD FRONT AND UPPER LOW...MOSTLY BROKEN
SKIES AND ISOLATED POP-UP SHOWERS WILL CONTINUE FOR THE PHX AREA
TERMINALS INTO THIS EVENING. CIGS WILL VARY BETWEEN 5-7KFT OR
SO...SAVE FOR ANY BRIEF LOWERING IF A STRAY SHOWER PASSES OVER THE
TERMINAL. FEEL THE SHOWER COVERAGE SHOULD BE SPARSE ENOUGH THROUGH
THE EVENING THAT VCSH MENTION IS WARRANTED FOR KSDL...LESS SO FOR
KPHX AND KIWA. SURFACE WINDS WILL CONTINUE IN A SOUTH TO SLIGHT
SOUTHEASTERLY ATTITUDE WITH A BRIEF PERIOD OF SOUTHWESTERLY LATER IN
THE AFTERNOON...WITH PERIODIC GUSTS IN THE 20KT RANGE. LONG AWAITED
COLD-FRONT AND PRECIP BAND WILL MOVE IN FROM THE WEST
OVERNIGHT...INCREASING SHOWER COVERAGE MOSTLY AFTER 02/07Z AND
BLOSSOMING INTO AREAS OF MODERATE AND PERSISTENT RAINFALL MONDAY
MORNING...CLOSER TOWARDS 02/13-14Z. INTRODUCED MVFR CIGS AND LOWERED
VSBYS TOWARDS THE END OF THE 01/18Z TAFS. CONFIDENCE IS HIGH FOR THE
SEVERAL HOURS/ROUNDS OF RAINFALL IN THE AM AND MEDIUM FOR THE CIGS
HEIGHTS ATTM. EXPECT WITH THE AMPLE AMOUNT OF LOW LEVEL MOISTURE AND
RAINFALL...TERRAIN OBSCURATIONS WILL BE WIDESPREAD ACROSS THE PHX
METRO THROUGH PORTIONS MONDAY.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
BROAD BAND OF PRECIPITATION WILL CONTINUE TO STRETCH ACROSS
SOUTHEAST CA...FROM KIPL THROUGH KBLH...THROUGH THIS EVENING. LOW
END VFR AND MVFR CIGS WILL RESULT...WITH EVEN SOME SCUD/MIST FEW/SCT
DEVELOPMENT FEW HUNDRED FEET OFF THE SURFACE. PERIODS OF
MODERATE...TO AT TIMES HEAVY...RAINFALL WILL CONTINUE TO MOVE
SOUTHWEST TO NORTHEAST ACROSS THE AREA THROUGH THE EVENING...BEFORE
GRADUALLY TAPERING OFF IN COVERAGE AFTER 02/08-09Z. SURFACE WINDS
WILL CONTINUE TO BE ON THE LIGHT SIDE...ATTEMPT SOME WEST TO
NORTHWEST HEADINGS...OTHERWISE REMAIN VARIABLE. RAIN SHOWER COVERAGE
WILL THIN TOWARDS THE MORNING...BUT WITH STILL ENOUGH COVERAGE TO
WARRANT VCSH MENTION. FAIRLY DECENT RAINFALL ACCUMULATIONS ARE
EXPECTED...WHICH WILL LEAD TO PONDING OF WATER ON APRON AND RUNWAY
SURFACES INTO MONDAY.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ020>021.
     FLOOD WATCH FROM MIDNIGHT TONIGHT THROUGH 8 PM MONDAY
     AZZ022>024.

CA...FLOOD WATCH UNTIL 12 PM MONDAY CAZ031>033.

&&

$$

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

DISCUSSION...AJ/LEINS
AVIATION...NOLTE
FIRE WEATHER...KUHLMAN







000
FXUS65 KPSR 020322
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
820 PM MST SUN MAR 1 2015

...POTENTIAL FOR HEAVY RAIN AFFECTING THE SOUTHWEST AND SOUTH
CENTRAL AZ DESERTS THROUGH LATE MONDAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL EXPAND FROM SOUTHEAST CALIFORNIA INTO
ARIZONA TONIGHT AND SLOWLY SHIFT EASTWARD DURING THE DAY MONDAY.
PERIODS OF MODERATE TO HEAVY RAIN ARE ANTICIPATED...ESPECIALLY OVER
HIGHER TERRAIN AND FOOTHILL LOCATIONS. THERE WILL ALSO BE A SLIGHT
CHANCE OF THUNDERSTORMS DURING THE DAY MONDAY...MAINLY OVER PORTIONS
OF ARIZONA. COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS SYSTEM WITH
BELOW NORMAL READINGS EXPECTED MONDAY THROUGH MID WEEK. A RETURN TO
ABOVE NORMAL TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
THE COLD UPPER TROF THAT HAD BEEN DEVELOPING SLOWLY SOUTH ALONG THE
CENTRAL AND SOUTHERN CA COAST THE PAST 36 HOURS...AND HAS BEEN
SLOWLY CIRCULATING APPRECIABLE AMOUNTS OF LOW LEVEL MOISTURE INTO
THE REGION...HAS BEGUN TO KICK INLAND THIS EVENING. SAT IMAGERY
SHOWED A WELL DEFINED KICKER TROF MOVING RAPIDLY SOUTH THROUGH THE
PACIFIC NORTHWEST UNDER NORTHERLY FLOW ALOFT.

AS A RESULT...REGIONAL UPPER AIR DATA SHOWED A PROFOUNDLY SHARP
BAROCLINIC ZONE ACROSS SOUTHERN CA/SOUTHERN NEVADA THAT HAS BACKED
AND INCREASED THE WINDS ALOFT SINCE MORNING. 700 MB WINDS ALONG THE
COLORADO RIVER WERE NEARLY SOUTH AT 40 KNOTS WHILE 300 MB WINDS WERE
WERE SOUTHWEST 100-120 KNOTS AND DIFLUENT. ALSO...MORE BOUNDARY
LAYER MOISTURE HAS TRANSPORTED NORTH ALONG THE FRONTAL ZONE AND
CURRENTLY FOCUSED IN SOUTHEAST CA/COLORADO RIVER WHERE FAST MOVING
BANDS OF PRECIP HAVE INCREASED THE PAST FEW HOURS.

THEREFORE AS THE COLD DYNAMICAL SYSTEM MOVES INLAND FROM OFFSHORE
SOUTHERN CA/NORTHERN BAJA TONIGHT...AN UPSWING IN PRECIP IS
EXPECTED. PRECIP WILL FOCUS ALONG THE COLORADO RIVER BY MIDNIGHT...
MOVING INTO SOUTHWEST AZ BY 12Z MON...THEN INTO CENTRAL AZ INCLUDING
PHOENIX BY 18Z MON. SINCE SOUTHERLY LOW LEVEL WINDS ARE FAIRLY
STRONG...ENHANCED UPSLOPE PRECIP WILL BE A BIG FACTOR IN THE
POTENTIAL FOR HEAVY RAIN AND RUNOFF. THE FLASH FLOOD WATCH THROUGH
MONDAY...FOCUSED IN THE UPSLOPE AREAS OF SOUTHWEST AND SOUTH CENTRAL
AZ WHERE MOUNTAIN WASHES DRAIN SOUTH INTO THE LOWER DESERTS LOOKS
GOOD FOR NOW.  A QUICK LOOK AT SOME OF THE OFFICE WARM COLLISION
COALESCENCE RAIN STUDIES INDICATE THE POTENTIAL FOR 0.50-0.60 INCHES
ON THE LOWER CENTRAL DESERTS TO NEARLY 2 INCHES IN THE MOUNTAINS AND
FOOTHILLS NORTHWEST THROUGH EAST OF PHOENIX MONDAY.

CURRENT FORECASTS LOOK IN GOOD SHAPE WITH HIGH PRECIP PROBABILITIES
AND THE POTENTIAL FOR HEAVY RAIN. NO UPDATES PLANNED. PREVIOUS
DISCUSSION BELOW STILL APPLIES.



.PREVIOUS DISCUSSION...302 PM MST...

REST OF TODAY THROUGH WEDNESDAY...
SHOWERS HAVE MOVED OVER OUR SOUTHEAST CALIFORNIA ZONES TODAY.
ISOLATED SHOWERS HAVE STARTED TO DEVELOP ELSEWHERE INCLUDING THE
PHOENIX AREA. MADE SOME EARLIER CHANGES TO THE FORECAST TO EXPAND
THE AREAL FLOOD WATCH TO SOUTHEAST CALIFORNIA. THE OTHER MAIN CHANGE
INCLUDED ANOTHER TIMING ADJUSTMENT FOR SOUTH-CENTRAL
ARIZONA...INCLUDING THE PHOENIX AREA...FOR A LATER START AND END. IN
SHORT...ANTICIPATE A SLOW RUNOFF RESPONSE TO THE RAINFALL BUT EXPECT
THERE WILL BE WASHES WITH SUFFICIENT FLOW TO CAUSE DANGEROUS
CONDITIONS AT SOME OF THE UNBRIDGED CROSSINGS. THERE WILL BE SOME
HIGHWAY DIPS AND OTHER LOW LYING AREAS THAT WILL SEE SOME INUNDATION
AS WELL. THE MAIN PRECIP MECHANISMS WITHIN THE LOW PRESSURE SYSTEM
ARE THE FRONTAL ZONE...CURRENTLY EXTENDING SOUTHWESTWARD FROM THE
MOHAVE DESERT...AND DYNAMICAL FORCING FROM SOME DIFFLUENCE RELATED
UPPER LEVEL DIVERGENCE...MAINLY NORTHWEST ARIZONA...AS WELL AS QG
FORCING FROM THE VORTICITY AND WARM AIR ADVECTION. THERE WILL ALSO
BE SOME INFLUENCE FROM THE RIGHT ENTRANCE REGION OF THE JET FOR
TOMORROW. THE FRONT IS ANTICIPATED TO MOVE THROUGH THE PHOENIX AREA
LATE MORNING/MIDDAY WITH PRECIP TRENDING DOWN FROM WEST TO EAST OVER
THE LOWER DESERTS OF ARIZONA IN MONDAY AFTERNOON...CONTINUING HIGHER
TERRAIN. THE MODELS ARE IN GENERALLY GOOD AGREEMENT ON THE TIMING
AND PLACEMENT OF THESE FEATURES THOUGH THE GFS IS A BIT MORE
GENEROUS WITH THE QG FORCING THAN NAM WHILE ECMWF IS A BIT SLOWER
WITH THE ONSET AND DEPARTURE OF PRECIP THAN NAM AND GFS. SEE THE
FLOOD WATCH FOR DETAILS ON THE TIMING AND PRECIP AMOUNTS. THE
UPSTREAM SYSTEM THAT WILL BE HELPING TO MOVE THIS MAIN ONE ALONG IS
CURRENTLY CENTERED NEAR THE ALASKA/CANADA BORDER. IT WILL RAPIDLY
MOVE DOWN THE COAST MONDAY AND THEN INTO NORTHWEST MEXICO TUESDAY.
MEANWHILE ANOTHER SHORT WAVE TRACKS THROUGH THE GREAT BASIN.
OUR FORECAST AREA WILL LARGELY BE BETWEEN THESE FEATURES BUT THEY
WILL CAUSE US TO KEEP A LINGERING SLIGHT CHANCE GOING...MAINLY OVER
SOUTH-CENTRAL ARIZONA. A MUCH WEAKER SHORT WAVE IS ADVERTISED TO
SLIDE DOWN FROM THE NORTH ON WEDNESDAY FOR SLIGHT CHANCES LIMITED TO
THE HIGHER TERRAIN OF SOUTH-CENTRAL AZ. SNOW LEVELS DROP TO NEAR
5000 FEET...INITIALLY OVER SOUTHEAST CALIFORNIA MONDAY MORNING THEN
EASTWARD TO SOUTH-CENTRAL ARIZONA BY EARLY MONDAY EVENING. THE
PRECIP WILL LARGELY BE OVER BY THE TIME THE SNOW LEVELS GET THAT LOW
AND THUS NO NOTABLE ACCUMULATIONS FOR OUR AREA...PERHAPS A DUSTING.
MADE A NUMBER OF TWEAKS TO THE POP/QPF GRIDS BUT NO MAJOR
ALTERATIONS FROM PREVIOUS PACKAGE. AS FOR TEMPERATURES...ANTICIPATE
LITTLE CHANGE OVER SOUTHEAST CALIFORNIA MONDAY SINCE THEY HAVE
ALREADY BEEN GETTING PRECIP. IT WILL BE MUCH COOLER THOUGH EAST OF
THE LOWER COLORADO RIVER VALLEY...ESPECIALLY SOUTH-CENTRAL ARIZONA.
IN FACT...PHOENIX AREA HIGH TEMP MONDAY MAY OCCUR BEFORE SUNRISE
WITH AFTERNOON PEAK IN THE 50S. WITH THE FOLLOW ON DISTURBANCES
TUESDAY AND WEDNESDAY...TEMPS WILL BE SLOW TO WARM UP THE FIRST HALF
OF THE WEEK.

FROM MID-WEEK ONWARD...RIDGING WILL TAKE HOLD ACROSS THE REGION AND
CONSEQUENTLY TEMPERATURES WILL ALSO CLIMB BACK ABOVE NORMAL BY LATE
WEEK INTO THE WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
AHEAD OF AN APPROACHING COLD FRONT AND UPPER LOW...MOSTLY BROKEN
SKIES AND ISOLATED POP-UP SHOWERS WILL CONTINUE FOR THE PHX AREA
TERMINALS INTO THIS EVENING. CIGS WILL VARY BETWEEN 5-7KFT OR
SO...SAVE FOR ANY BRIEF LOWERING IF A STRAY SHOWER PASSES OVER THE
TERMINAL. FEEL THE SHOWER COVERAGE SHOULD BE SPARSE ENOUGH THROUGH
THE EVENING THAT VCSH MENTION IS WARRANTED FOR KSDL...LESS SO FOR
KPHX AND KIWA. SURFACE WINDS WILL CONTINUE IN A SOUTH TO SLIGHT
SOUTHEASTERLY ATTITUDE WITH A BRIEF PERIOD OF SOUTHWESTERLY LATER IN
THE AFTERNOON...WITH PERIODIC GUSTS IN THE 20KT RANGE. LONG AWAITED
COLD-FRONT AND PRECIP BAND WILL MOVE IN FROM THE WEST
OVERNIGHT...INCREASING SHOWER COVERAGE MOSTLY AFTER 02/07Z AND
BLOSSOMING INTO AREAS OF MODERATE AND PERSISTENT RAINFALL MONDAY
MORNING...CLOSER TOWARDS 02/13-14Z. INTRODUCED MVFR CIGS AND LOWERED
VSBYS TOWARDS THE END OF THE 01/18Z TAFS. CONFIDENCE IS HIGH FOR THE
SEVERAL HOURS/ROUNDS OF RAINFALL IN THE AM AND MEDIUM FOR THE CIGS
HEIGHTS ATTM. EXPECT WITH THE AMPLE AMOUNT OF LOW LEVEL MOISTURE AND
RAINFALL...TERRAIN OBSCURATIONS WILL BE WIDESPREAD ACROSS THE PHX
METRO THROUGH PORTIONS MONDAY.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
BROAD BAND OF PRECIPITATION WILL CONTINUE TO STRETCH ACROSS
SOUTHEAST CA...FROM KIPL THROUGH KBLH...THROUGH THIS EVENING. LOW
END VFR AND MVFR CIGS WILL RESULT...WITH EVEN SOME SCUD/MIST FEW/SCT
DEVELOPMENT FEW HUNDRED FEET OFF THE SURFACE. PERIODS OF
MODERATE...TO AT TIMES HEAVY...RAINFALL WILL CONTINUE TO MOVE
SOUTHWEST TO NORTHEAST ACROSS THE AREA THROUGH THE EVENING...BEFORE
GRADUALLY TAPERING OFF IN COVERAGE AFTER 02/08-09Z. SURFACE WINDS
WILL CONTINUE TO BE ON THE LIGHT SIDE...ATTEMPT SOME WEST TO
NORTHWEST HEADINGS...OTHERWISE REMAIN VARIABLE. RAIN SHOWER COVERAGE
WILL THIN TOWARDS THE MORNING...BUT WITH STILL ENOUGH COVERAGE TO
WARRANT VCSH MENTION. FAIRLY DECENT RAINFALL ACCUMULATIONS ARE
EXPECTED...WHICH WILL LEAD TO PONDING OF WATER ON APRON AND RUNWAY
SURFACES INTO MONDAY.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ020>021.
     FLOOD WATCH FROM MIDNIGHT TONIGHT THROUGH 8 PM MONDAY
     AZZ022>024.

CA...FLOOD WATCH UNTIL 12 PM MONDAY CAZ031>033.

&&

$$

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

DISCUSSION...AJ/LEINS
AVIATION...NOLTE
FIRE WEATHER...KUHLMAN








000
FXUS65 KPSR 012203 AAA
AFDPSR

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE PHOENIX AZ
302 PM MST SUN MAR 1 2015

...WINTER WEATHER EVENT AFFECTING THE DESERT SOUTHWEST THROUGH LATE
MONDAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL EXPAND FROM SOUTHEAST CALIFORNIA INTO
ARIZONA TONIGHT AND SLOWLY SHIFT EASTWARD DURING THE DAY MONDAY.
PERIODS OF MODERATE TO HEAVY RAIN ARE ANTICIPATED...ESPECIALLY OVER
HIGHER TERRAIN AND FOOTHILL LOCATIONS. THERE WILL ALSO BE A SLIGHT
CHANCE OF THUNDERSTORMS DURING THE DAY MONDAY...MAINLY OVER PORTIONS
OF ARIZONA. COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS SYSTEM WITH
BELOW NORMAL READINGS EXPECTED MONDAY THROUGH MID WEEK. A RETURN TO
ABOVE NORMAL TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
REST OF TODAY THROUGH WEDNESDAY...
SHOWERS HAVE MOVED OVER OUR SOUTHEAST CALIFORNIA ZONES TODAY.
ISOLATED SHOWERS HAVE STARTED TO DEVELOP ELSEWHERE INCLUDING THE
PHOENIX AREA. MADE SOME EARLIER CHANGES TO THE FORECAST TO EXPAND
THE AREAL FLOOD WATCH TO SOUTHEAST CALIFORNIA. THE OTHER MAIN CHANGE
INCLUDED ANOTHER TIMING ADJUSTMENT FOR SOUTH-CENTRAL
ARIZONA...INCLUDING THE PHOENIX AREA...FOR A LATER START AND END. IN
SHORT...ANTICIPATE A SLOW RUNOFF RESPONSE TO THE RAINFALL BUT EXPECT
THERE WILL BE WASHES WITH SUFFICIENT FLOW TO CAUSE DANGEROUS
CONDITIONS AT SOME OF THE UNBRIDGED CROSSINGS. THERE WILL BE SOME
HIGHWAY DIPS AND OTHER LOW LYING AREAS THAT WILL SEE SOME INUNDATION
AS WELL. THE MAIN PRECIP MECHANISMS WITHIN THE LOW PRESSURE SYSTEM
ARE THE FRONTAL ZONE...CURRENTLY EXTENDING SOUTHWESTWARD FROM THE
MOHAVE DESERT...AND DYNAMICAL FORCING FROM SOME DIFFLUENCE RELATED
UPPER LEVEL DIVERGENCE...MAINLY NORTHWEST ARIZONA...AS WELL AS QG
FORCING FROM THE VORTICITY AND WARM AIR ADVECTION. THERE WILL ALSO
BE SOME INFLUENCE FROM THE RIGHT ENTRANCE REGION OF THE JET FOR
TOMORROW. THE FRONT IS ANTICIPATED TO MOVE THROUGH THE PHOENIX AREA
LATE MORNING/MIDDAY WITH PRECIP TRENDING DOWN FROM WEST TO EAST OVER
THE LOWER DESERTS OF ARIZONA IN MONDAY AFTERNOON...CONTINUING HIGHER
TERRAIN. THE MODELS ARE IN GENERALLY GOOD AGREEMENT ON THE TIMING
AND PLACEMENT OF THESE FEATURES THOUGH THE GFS IS A BIT MORE
GENEROUS WITH THE QG FORCING THAN NAM WHILE ECMWF IS A BIT SLOWER
WITH THE ONSET AND DEPARTURE OF PRECIP THAN NAM AND GFS. SEE THE
FLOOD WATCH FOR DETAILS ON THE TIMING AND PRECIP AMOUNTS. THE
UPSTREAM SYSTEM THAT WILL BE HELPING TO MOVE THIS MAIN ONE ALONG IS
CURRENTLY CENTERED NEAR THE ALASKA/CANADA BORDER. IT WILL RAPIDLY
MOVE DOWN THE COAST MONDAY AND THEN INTO NORTHWEST MEXICO TUESDAY.
MEANWHILE ANOTHER SHORT WAVE TRACKS THROUGH THE GREAT BASIN.
OUR FORECAST AREA WILL LARGELY BE BETWEEN THESE FEATURES BUT THEY
WILL CAUSE US TO KEEP A LINGERING SLIGHT CHANCE GOING...MAINLY OVER
SOUTH-CENTRAL ARIZONA. A MUCH WEAKER SHORT WAVE IS ADVERTISED TO
SLIDE DOWN FROM THE NORTH ON WEDNESDAY FOR SLIGHT CHANCES LIMITED TO
THE HIGHER TERRAIN OF SOUTH-CENTRAL AZ. SNOW LEVELS DROP TO NEAR
5000 FEET...INITIALLY OVER SOUTHEAST CALIFORNIA MONDAY MORNING THEN
EASTWARD TO SOUTH-CENTRAL ARIZONA BY EARLY MONDAY EVENING. THE
PRECIP WILL LARGELY BE OVER BY THE TIME THE SNOW LEVELS GET THAT LOW
AND THUS NO NOTABLE ACCUMULATIONS FOR OUR AREA...PERHAPS A DUSTING.
MADE A NUMBER OF TWEAKS TO THE POP/QPF GRIDS BUT NO MAJOR
ALTERATIONS FROM PREVIOUS PACKAGE. AS FOR TEMPERATURES...ANTICIPATE
LITTLE CHANGE OVER SOUTHEAST CALIFORNIA MONDAY SINCE THEY HAVE
ALREADY BEEN GETTING PRECIP. IT WILL BE MUCH COOLER THOUGH EAST OF
THE LOWER COLORADO RIVER VALLEY...ESPECIALLY SOUTH-CENTRAL ARIZONA.
IN FACT...PHOENIX AREA HIGH TEMP MONDAY MAY OCCUR BEFORE SUNRISE
WITH AFTERNOON PEAK IN THE 50S. WITH THE FOLLOW ON DISTURBANCES
TUESDAY AND WEDNESDAY...TEMPS WILL BE SLOW TO WARM UP THE FIRST HALF
OF THE WEEK.

FROM MID-WEEK ONWARD...RIDGING WILL TAKE HOLD ACROSS THE REGION AND
CONSEQUENTLY TEMPERATURES WILL ALSO CLIMB BACK ABOVE NORMAL BY LATE
WEEK INTO THE WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
AHEAD OF AN APPROACHING COLD FRONT AND UPPER LOW...MOSTLY BROKEN
SKIES AND ISOLATED POP-UP SHOWERS WILL CONTINUE FOR THE PHX AREA
TERMINALS INTO THIS EVENING. CIGS WILL VARY BETWEEN 5-7KFT OR
SO...SAVE FOR ANY BRIEF LOWERING IF A STRAY SHOWER PASSES OVER THE
TERMINAL. FEEL THE SHOWER COVERAGE SHOULD BE SPARSE ENOUGH THROUGH
THE EVENING THAT VCSH MENTION IS WARRANTED FOR KSDL...LESS SO FOR
KPHX AND KIWA. SURFACE WINDS WILL CONTINUE IN A SOUTH TO SLIGHT
SOUTHEASTERLY ATTITUDE WITH A BRIEF PERIOD OF SOUTHWESTERLY LATER IN
THE AFTERNOON...WITH PERIODIC GUSTS IN THE 20KT RANGE. LONG AWAITED
COLD-FRONT AND PRECIP BAND WILL MOVE IN FROM THE WEST
OVERNIGHT...INCREASING SHOWER COVERAGE MOSTLY AFTER 02/07Z AND
BLOSSOMING INTO AREAS OF MODERATE AND PERSISTENT RAINFALL MONDAY
MORNING...CLOSER TOWARDS 02/13-14Z. INTRODUCED MVFR CIGS AND LOWERED
VSBYS TOWARDS THE END OF THE 01/18Z TAFS. CONFIDENCE IS HIGH FOR THE
SEVERAL HOURS/ROUNDS OF RAINFALL IN THE AM AND MEDIUM FOR THE CIGS
HEIGHTS ATTM. EXPECT WITH THE AMPLE AMOUNT OF LOW LEVEL MOISTURE AND
RAINFALL...TERRAIN OBSCURATIONS WILL BE WIDESPREAD ACROSS THE PHX
METRO THROUGH PORTIONS MONDAY.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
BROAD BAND OF PRECIPITATION WILL CONTINUE TO STRETCH ACROSS
SOUTHEAST CA...FROM KIPL THROUGH KBLH...THROUGH THIS EVENING. LOW
END VFR AND MVFR CIGS WILL RESULT...WITH EVEN SOME SCUD/MIST FEW/SCT
DEVELOPMENT FEW HUNDRED FEET OFF THE SURFACE. PERIODS OF
MODERATE...TO AT TIMES HEAVY...RAINFALL WILL CONTINUE TO MOVE
SOUTHWEST TO NORTHEAST ACROSS THE AREA THROUGH THE EVENING...BEFORE
GRADUALLY TAPERING OFF IN COVERAGE AFTER 02/08-09Z. SURFACE WINDS
WILL CONTINUE TO BE ON THE LIGHT SIDE...ATTEMPT SOME WEST TO
NORTHWEST HEADINGS...OTHERWISE REMAIN VARIABLE. RAIN SHOWER COVERAGE
WILL THIN TOWARDS THE MORNING...BUT WITH STILL ENOUGH COVERAGE TO
WARRANT VCSH MENTION. FAIRLY DECENT RAINFALL ACCUMULATIONS ARE
EXPECTED...WHICH WILL LEAD TO PONDING OF WATER ON APRON AND RUNWAY
SURFACES INTO MONDAY.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ020>021.
     FLOOD WATCH FROM MIDNIGHT TONIGHT THROUGH 8 PM MONDAY
     AZZ022>024.

CA...FLOOD WATCH UNTIL 12 PM MONDAY CAZ031>033.

&&

$$

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

DISCUSSION...AJ/LEINS
AVIATION...NOLTE
FIRE WEATHER...KUHLMAN











000
FXUS65 KPSR 012150
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
250 PM MST SUN MAR 1 2015

...WINTER WEATHER EVENT AFFECTING THE DESERT SOUTHWEST THROUGH LATE
MONDAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL EXPAND FROM SOUTHEAST CALIFORNIA INTO
ARIZONA TONIGHT AND SLOWLY SHIFT EASTWARD DURING THE DAY MONDAY.
PERIODS OF MODERATE TO HEAVY RAIN ARE ANTICIPATED...ESPECIALLY OVER
HIGHER TERRAIN AND FOOTHILL LOCATIONS. THERE WILL ALSO BE A SLIGHT
CHANCE OF THUNDERSTORMS DURING THE DAY MONDAY...MAINLY OVER PORTIONS
OF ARIZONA. COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS SYSTEM WITH
BELOW NORMAL READINGS EXPECTED MONDAY THROUGH MID WEEK. A RETURN TO
ABOVE NORMAL TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
REST OF TODAY THROUGH WEDNESDAY...
SHOWERS HAVE MOVED OVER OUR SOUTHEAST CALIFORNIA ZONES TODAY.
ISOLATED SHOWERS HAVE STARTED TO DEVELOP ELSEWHERE INCLUDING THE
PHOENIX AREA. MADE SOME EARLIER CHANGES TO THE FORECAST TO EXPAND
THE AREAL FLOOD WATCH TO SOUTHEAST CALIFORNIA. THE OTHER MAIN CHANGE
INCLUDED ANOTHER TIMING ADJUSTMENT FOR SOUTH-CENTRAL
ARIZONA...INCLUDING THE PHOENIX AREA...FOR A LATER START AND END. IN
SHORT...ANTICIPATE A SLOW RUNOFF RESPONSE TO THE RAINFALL BUT EXPECT
THERE WILL BE WASHES WITH SUFFICIENT FLOW TO CAUSE DANGEROUS
CONDITIONS AT SOME OF THE UNBRIDGED CROSSINGS. THERE WILL BE SOME
HIGHWAY DIPS AND OTHER LOW LYING AREAS THAT WILL SEE SOME INUNDATION
AS WELL. THE MAIN PRECIP MECHANISMS WITHIN THE LOW PRESSURE SYSTEM
ARE THE FRONTAL ZONE...CURRENTLY EXTENDING SOUTHWESTWARD FROM THE
MOHAVE DESERT...AND DYNAMICAL FORCING FROM SOME DIFFLUENCE RELATED
UPPER LEVEL DIVERGENCE...MAINLY NORTHWEST ARIZONA...AS WELL AS QG
FORCING FROM THE VORTICITY AND WARM AIR ADVECTION. THERE WILL ALSO
BE SOME INFLUENCE FROM THE RIGHT ENTRANCE REGION OF THE JET FOR
TOMORROW. THE FRONT IS ANTICIPATED TO MOVE THROUGH THE PHOENIX AREA
LATE MORNING/MIDDAY WITH PRECIP TRENDING DOWN FROM WEST TO EAST OVER
THE LOWER DESERTS OF ARIZONA IN MONDAY AFTERNOON...CONTINUING HIGHER
TERRAIN. THE MODELS ARE IN GENERALLY GOOD AGREEMENT ON THE TIMING
AND PLACEMENT OF THESE FEATURES THOUGH THE GFS IS A BIT MORE
GENEROUS WITH THE QG FORCING THAN NAM WHILE ECMWF IS A BIT SLOWER
WITH THE ONSET AND DEPARTURE OF PRECIP THAN NAM AND GFS. SEE THE
FLOOD WATCH FOR DETAILS ON THE TIMING AND PRECIP AMOUNTS. THE
UPSTREAM SYSTEM THAT WILL BE HELPING TO MOVE THIS MAIN ONE ALONG IS
CURRENTLY CENTERED NEAR THE ALASKA/CANADA BORDER. IT WILL RAPIDLY
MOVE DOWN THE COAST MONDAY AND THEN INTO NORTHWEST MEXICO TUESDAY.
MEANWHILE ANOTHER SHORT WAVE TRACKS THROUGH THE GREAT BASIN.
OUR FORECAST AREA WILL LARGELY BE BETWEEN THESE FEATURES BUT THEY
WILL CAUSE US TO KEEP A LINGERING SLIGHT CHANCE GOING...MAINLY OVER
SOUTH-CENTRAL ARIZONA. A MUCH WEAKER SHORT WAVE IS ADVERTISED TO
SLIDE DOWN FROM THE NORTH ON WEDNESDAY FOR SLIGHT CHANCES LIMITED TO
THE HIGHER TERRAIN OF SOUTH-CENTRAL AZ. SNOW LEVELS DROP TO NEAR
5000 FEET...INITIALLY OVER SOUTHEAST CALIFORNIA MONDAY MORNING THEN
EASTWARD TO SOUTH-CENTRAL ARIZONA BY EARLY MONDAY EVENING. THE
PRECIP WILL LARGELY BE OVER BY THE TIME THE SNOW LEVELS GET THAT LOW
AND THUS NO NOTABLE ACCUMULATIONS FOR OUR AREA...PERHAPS A DUSTING.
MADE A NUMBER OF TWEAKS TO THE POP/QPF GRIDS BUT NO MAJOR
ALTERATIONS FROM PREVIOUS PACKAGE. AS FOR TEMPERATURES...ANTICIPATE
LITTLE CHANGE OVER SOUTHEAST CALIFORNIA MONDAY SINCE THEY HAVE
ALREADY BEEN GETTING PRECIP. IT WILL BE MUCH COOLER THOUGH EAST OF
THE LOWER COLORADO RIVER VALLEY...ESPECIALLY SOUTH-CENTRAL ARIZONA.
IN FACT...PHOENIX AREA HIGH TEMP MONDAY MAY OCCUR BEFORE SUNRISE
WITH AFTERNOON PEAK IN THE 50S. WITH THE FOLLOW ON DISTURBANCES
TUESDAY AND WEDNESDAY...TEMPS WILL BE SLOW TO WARM UP THE FIRST HALF
OF THE WEEK.

FROM MID-WEEK ONWARD...RIDGING WILL TAKE HOLD ACROSS THE REGION AND
CONSEQUENTLY TEMPERATURES WILL ALSO CLIMB BACK ABOVE NORMAL BY LATE
WEEK INTO THE WEEKEND.

&&

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

A SLOW APPROACHING COLD FRONT WILL CONTINUE TO DRAW LOW LEVEL
MOISTURE INTO THE AREA FROM NORTHERN BAJA TODAY. ANY SHOWER ACTIVITY
THROUGH THIS AFTERNOON WILL MAINLY STAY TO THE NORTH AND WEST OF THE
PHOENIX TERMINALS...BUT A FEW LIGHT SHOWERS MAY AFFECT KSDL. CIGS
FOR NOW SHOULD STAY ABOVE 8KT FEET THROUGH THE AFTERNOON HOURS...BUT
IF ANY SHOWERS DO OCCUR...CIGS WOULD TEMPORARILY DROP TO AROUND 5-6K
FEET. THE COLD FRONT AND AREA OF RAIN WILL APPROACH THE PHOENIX AREA
SOMETIME LATE THIS EVENING INTO TONIGHT...BUT CONFIDENCE IN THE
EXACT TIME OF ARRIVAL OF THE RAIN...LOWER CIGS...AND ANY RESTRICTED
VISIBILITIES IS STILL SOMEWHAT LOW.

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

MID LEVEL CIGS WILL GRADUALLY LOWER THIS MORNING AND EVENTUALLY DROP
TO MVFR BY AROUND NOON AFTER SOME STEADY RAIN MOVES IN. CONFIDENCE
IS FAIRLY HIGH THAT A BAND OF LIGHT TO MODERATE RAIN WILL AFFECT
SOUTHEAST CALIFORNIA AND PORTIONS OF SOUTHWEST ARIZONA THIS
AFTERNOON INTO THIS EVENING. MAY SEE SOME MVFR VISIBILITIES AT TIMES
DUE TO THE RAIN AND POTENTIALLY IFR CIGS BRIEFLY DEPENDING ON HOW
STEADY THE RAIN ENDS UP BEING. RAIN SHOULD DIMINISH AFTER 09Z
TONIGHT WITH GRADUALLY IMPROVING CIGS BY 12Z MONDAY MORNING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ020>021.
     FLOOD WATCH FROM MIDNIGHT TONIGHT THROUGH 8 PM MONDAY
     AZZ022>024.

CA...FLOOD WATCH UNTIL 12 PM MONDAY CAZ031>033.

&&

$$

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

DISCUSSION...AJ/LEINS
AVIATION...KUHLMAN
FIRE WEATHER...KUHLMAN







000
FXUS65 KPSR 012150
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
250 PM MST SUN MAR 1 2015

...WINTER WEATHER EVENT AFFECTING THE DESERT SOUTHWEST THROUGH LATE
MONDAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL EXPAND FROM SOUTHEAST CALIFORNIA INTO
ARIZONA TONIGHT AND SLOWLY SHIFT EASTWARD DURING THE DAY MONDAY.
PERIODS OF MODERATE TO HEAVY RAIN ARE ANTICIPATED...ESPECIALLY OVER
HIGHER TERRAIN AND FOOTHILL LOCATIONS. THERE WILL ALSO BE A SLIGHT
CHANCE OF THUNDERSTORMS DURING THE DAY MONDAY...MAINLY OVER PORTIONS
OF ARIZONA. COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS SYSTEM WITH
BELOW NORMAL READINGS EXPECTED MONDAY THROUGH MID WEEK. A RETURN TO
ABOVE NORMAL TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
REST OF TODAY THROUGH WEDNESDAY...
SHOWERS HAVE MOVED OVER OUR SOUTHEAST CALIFORNIA ZONES TODAY.
ISOLATED SHOWERS HAVE STARTED TO DEVELOP ELSEWHERE INCLUDING THE
PHOENIX AREA. MADE SOME EARLIER CHANGES TO THE FORECAST TO EXPAND
THE AREAL FLOOD WATCH TO SOUTHEAST CALIFORNIA. THE OTHER MAIN CHANGE
INCLUDED ANOTHER TIMING ADJUSTMENT FOR SOUTH-CENTRAL
ARIZONA...INCLUDING THE PHOENIX AREA...FOR A LATER START AND END. IN
SHORT...ANTICIPATE A SLOW RUNOFF RESPONSE TO THE RAINFALL BUT EXPECT
THERE WILL BE WASHES WITH SUFFICIENT FLOW TO CAUSE DANGEROUS
CONDITIONS AT SOME OF THE UNBRIDGED CROSSINGS. THERE WILL BE SOME
HIGHWAY DIPS AND OTHER LOW LYING AREAS THAT WILL SEE SOME INUNDATION
AS WELL. THE MAIN PRECIP MECHANISMS WITHIN THE LOW PRESSURE SYSTEM
ARE THE FRONTAL ZONE...CURRENTLY EXTENDING SOUTHWESTWARD FROM THE
MOHAVE DESERT...AND DYNAMICAL FORCING FROM SOME DIFFLUENCE RELATED
UPPER LEVEL DIVERGENCE...MAINLY NORTHWEST ARIZONA...AS WELL AS QG
FORCING FROM THE VORTICITY AND WARM AIR ADVECTION. THERE WILL ALSO
BE SOME INFLUENCE FROM THE RIGHT ENTRANCE REGION OF THE JET FOR
TOMORROW. THE FRONT IS ANTICIPATED TO MOVE THROUGH THE PHOENIX AREA
LATE MORNING/MIDDAY WITH PRECIP TRENDING DOWN FROM WEST TO EAST OVER
THE LOWER DESERTS OF ARIZONA IN MONDAY AFTERNOON...CONTINUING HIGHER
TERRAIN. THE MODELS ARE IN GENERALLY GOOD AGREEMENT ON THE TIMING
AND PLACEMENT OF THESE FEATURES THOUGH THE GFS IS A BIT MORE
GENEROUS WITH THE QG FORCING THAN NAM WHILE ECMWF IS A BIT SLOWER
WITH THE ONSET AND DEPARTURE OF PRECIP THAN NAM AND GFS. SEE THE
FLOOD WATCH FOR DETAILS ON THE TIMING AND PRECIP AMOUNTS. THE
UPSTREAM SYSTEM THAT WILL BE HELPING TO MOVE THIS MAIN ONE ALONG IS
CURRENTLY CENTERED NEAR THE ALASKA/CANADA BORDER. IT WILL RAPIDLY
MOVE DOWN THE COAST MONDAY AND THEN INTO NORTHWEST MEXICO TUESDAY.
MEANWHILE ANOTHER SHORT WAVE TRACKS THROUGH THE GREAT BASIN.
OUR FORECAST AREA WILL LARGELY BE BETWEEN THESE FEATURES BUT THEY
WILL CAUSE US TO KEEP A LINGERING SLIGHT CHANCE GOING...MAINLY OVER
SOUTH-CENTRAL ARIZONA. A MUCH WEAKER SHORT WAVE IS ADVERTISED TO
SLIDE DOWN FROM THE NORTH ON WEDNESDAY FOR SLIGHT CHANCES LIMITED TO
THE HIGHER TERRAIN OF SOUTH-CENTRAL AZ. SNOW LEVELS DROP TO NEAR
5000 FEET...INITIALLY OVER SOUTHEAST CALIFORNIA MONDAY MORNING THEN
EASTWARD TO SOUTH-CENTRAL ARIZONA BY EARLY MONDAY EVENING. THE
PRECIP WILL LARGELY BE OVER BY THE TIME THE SNOW LEVELS GET THAT LOW
AND THUS NO NOTABLE ACCUMULATIONS FOR OUR AREA...PERHAPS A DUSTING.
MADE A NUMBER OF TWEAKS TO THE POP/QPF GRIDS BUT NO MAJOR
ALTERATIONS FROM PREVIOUS PACKAGE. AS FOR TEMPERATURES...ANTICIPATE
LITTLE CHANGE OVER SOUTHEAST CALIFORNIA MONDAY SINCE THEY HAVE
ALREADY BEEN GETTING PRECIP. IT WILL BE MUCH COOLER THOUGH EAST OF
THE LOWER COLORADO RIVER VALLEY...ESPECIALLY SOUTH-CENTRAL ARIZONA.
IN FACT...PHOENIX AREA HIGH TEMP MONDAY MAY OCCUR BEFORE SUNRISE
WITH AFTERNOON PEAK IN THE 50S. WITH THE FOLLOW ON DISTURBANCES
TUESDAY AND WEDNESDAY...TEMPS WILL BE SLOW TO WARM UP THE FIRST HALF
OF THE WEEK.

FROM MID-WEEK ONWARD...RIDGING WILL TAKE HOLD ACROSS THE REGION AND
CONSEQUENTLY TEMPERATURES WILL ALSO CLIMB BACK ABOVE NORMAL BY LATE
WEEK INTO THE WEEKEND.

&&

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

A SLOW APPROACHING COLD FRONT WILL CONTINUE TO DRAW LOW LEVEL
MOISTURE INTO THE AREA FROM NORTHERN BAJA TODAY. ANY SHOWER ACTIVITY
THROUGH THIS AFTERNOON WILL MAINLY STAY TO THE NORTH AND WEST OF THE
PHOENIX TERMINALS...BUT A FEW LIGHT SHOWERS MAY AFFECT KSDL. CIGS
FOR NOW SHOULD STAY ABOVE 8KT FEET THROUGH THE AFTERNOON HOURS...BUT
IF ANY SHOWERS DO OCCUR...CIGS WOULD TEMPORARILY DROP TO AROUND 5-6K
FEET. THE COLD FRONT AND AREA OF RAIN WILL APPROACH THE PHOENIX AREA
SOMETIME LATE THIS EVENING INTO TONIGHT...BUT CONFIDENCE IN THE
EXACT TIME OF ARRIVAL OF THE RAIN...LOWER CIGS...AND ANY RESTRICTED
VISIBILITIES IS STILL SOMEWHAT LOW.

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

MID LEVEL CIGS WILL GRADUALLY LOWER THIS MORNING AND EVENTUALLY DROP
TO MVFR BY AROUND NOON AFTER SOME STEADY RAIN MOVES IN. CONFIDENCE
IS FAIRLY HIGH THAT A BAND OF LIGHT TO MODERATE RAIN WILL AFFECT
SOUTHEAST CALIFORNIA AND PORTIONS OF SOUTHWEST ARIZONA THIS
AFTERNOON INTO THIS EVENING. MAY SEE SOME MVFR VISIBILITIES AT TIMES
DUE TO THE RAIN AND POTENTIALLY IFR CIGS BRIEFLY DEPENDING ON HOW
STEADY THE RAIN ENDS UP BEING. RAIN SHOULD DIMINISH AFTER 09Z
TONIGHT WITH GRADUALLY IMPROVING CIGS BY 12Z MONDAY MORNING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ020>021.
     FLOOD WATCH FROM MIDNIGHT TONIGHT THROUGH 8 PM MONDAY
     AZZ022>024.

CA...FLOOD WATCH UNTIL 12 PM MONDAY CAZ031>033.

&&

$$

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

DISCUSSION...AJ/LEINS
AVIATION...KUHLMAN
FIRE WEATHER...KUHLMAN








000
FXUS65 KPSR 012150
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
250 PM MST SUN MAR 1 2015

...WINTER WEATHER EVENT AFFECTING THE DESERT SOUTHWEST THROUGH LATE
MONDAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL EXPAND FROM SOUTHEAST CALIFORNIA INTO
ARIZONA TONIGHT AND SLOWLY SHIFT EASTWARD DURING THE DAY MONDAY.
PERIODS OF MODERATE TO HEAVY RAIN ARE ANTICIPATED...ESPECIALLY OVER
HIGHER TERRAIN AND FOOTHILL LOCATIONS. THERE WILL ALSO BE A SLIGHT
CHANCE OF THUNDERSTORMS DURING THE DAY MONDAY...MAINLY OVER PORTIONS
OF ARIZONA. COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS SYSTEM WITH
BELOW NORMAL READINGS EXPECTED MONDAY THROUGH MID WEEK. A RETURN TO
ABOVE NORMAL TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
REST OF TODAY THROUGH WEDNESDAY...
SHOWERS HAVE MOVED OVER OUR SOUTHEAST CALIFORNIA ZONES TODAY.
ISOLATED SHOWERS HAVE STARTED TO DEVELOP ELSEWHERE INCLUDING THE
PHOENIX AREA. MADE SOME EARLIER CHANGES TO THE FORECAST TO EXPAND
THE AREAL FLOOD WATCH TO SOUTHEAST CALIFORNIA. THE OTHER MAIN CHANGE
INCLUDED ANOTHER TIMING ADJUSTMENT FOR SOUTH-CENTRAL
ARIZONA...INCLUDING THE PHOENIX AREA...FOR A LATER START AND END. IN
SHORT...ANTICIPATE A SLOW RUNOFF RESPONSE TO THE RAINFALL BUT EXPECT
THERE WILL BE WASHES WITH SUFFICIENT FLOW TO CAUSE DANGEROUS
CONDITIONS AT SOME OF THE UNBRIDGED CROSSINGS. THERE WILL BE SOME
HIGHWAY DIPS AND OTHER LOW LYING AREAS THAT WILL SEE SOME INUNDATION
AS WELL. THE MAIN PRECIP MECHANISMS WITHIN THE LOW PRESSURE SYSTEM
ARE THE FRONTAL ZONE...CURRENTLY EXTENDING SOUTHWESTWARD FROM THE
MOHAVE DESERT...AND DYNAMICAL FORCING FROM SOME DIFFLUENCE RELATED
UPPER LEVEL DIVERGENCE...MAINLY NORTHWEST ARIZONA...AS WELL AS QG
FORCING FROM THE VORTICITY AND WARM AIR ADVECTION. THERE WILL ALSO
BE SOME INFLUENCE FROM THE RIGHT ENTRANCE REGION OF THE JET FOR
TOMORROW. THE FRONT IS ANTICIPATED TO MOVE THROUGH THE PHOENIX AREA
LATE MORNING/MIDDAY WITH PRECIP TRENDING DOWN FROM WEST TO EAST OVER
THE LOWER DESERTS OF ARIZONA IN MONDAY AFTERNOON...CONTINUING HIGHER
TERRAIN. THE MODELS ARE IN GENERALLY GOOD AGREEMENT ON THE TIMING
AND PLACEMENT OF THESE FEATURES THOUGH THE GFS IS A BIT MORE
GENEROUS WITH THE QG FORCING THAN NAM WHILE ECMWF IS A BIT SLOWER
WITH THE ONSET AND DEPARTURE OF PRECIP THAN NAM AND GFS. SEE THE
FLOOD WATCH FOR DETAILS ON THE TIMING AND PRECIP AMOUNTS. THE
UPSTREAM SYSTEM THAT WILL BE HELPING TO MOVE THIS MAIN ONE ALONG IS
CURRENTLY CENTERED NEAR THE ALASKA/CANADA BORDER. IT WILL RAPIDLY
MOVE DOWN THE COAST MONDAY AND THEN INTO NORTHWEST MEXICO TUESDAY.
MEANWHILE ANOTHER SHORT WAVE TRACKS THROUGH THE GREAT BASIN.
OUR FORECAST AREA WILL LARGELY BE BETWEEN THESE FEATURES BUT THEY
WILL CAUSE US TO KEEP A LINGERING SLIGHT CHANCE GOING...MAINLY OVER
SOUTH-CENTRAL ARIZONA. A MUCH WEAKER SHORT WAVE IS ADVERTISED TO
SLIDE DOWN FROM THE NORTH ON WEDNESDAY FOR SLIGHT CHANCES LIMITED TO
THE HIGHER TERRAIN OF SOUTH-CENTRAL AZ. SNOW LEVELS DROP TO NEAR
5000 FEET...INITIALLY OVER SOUTHEAST CALIFORNIA MONDAY MORNING THEN
EASTWARD TO SOUTH-CENTRAL ARIZONA BY EARLY MONDAY EVENING. THE
PRECIP WILL LARGELY BE OVER BY THE TIME THE SNOW LEVELS GET THAT LOW
AND THUS NO NOTABLE ACCUMULATIONS FOR OUR AREA...PERHAPS A DUSTING.
MADE A NUMBER OF TWEAKS TO THE POP/QPF GRIDS BUT NO MAJOR
ALTERATIONS FROM PREVIOUS PACKAGE. AS FOR TEMPERATURES...ANTICIPATE
LITTLE CHANGE OVER SOUTHEAST CALIFORNIA MONDAY SINCE THEY HAVE
ALREADY BEEN GETTING PRECIP. IT WILL BE MUCH COOLER THOUGH EAST OF
THE LOWER COLORADO RIVER VALLEY...ESPECIALLY SOUTH-CENTRAL ARIZONA.
IN FACT...PHOENIX AREA HIGH TEMP MONDAY MAY OCCUR BEFORE SUNRISE
WITH AFTERNOON PEAK IN THE 50S. WITH THE FOLLOW ON DISTURBANCES
TUESDAY AND WEDNESDAY...TEMPS WILL BE SLOW TO WARM UP THE FIRST HALF
OF THE WEEK.

FROM MID-WEEK ONWARD...RIDGING WILL TAKE HOLD ACROSS THE REGION AND
CONSEQUENTLY TEMPERATURES WILL ALSO CLIMB BACK ABOVE NORMAL BY LATE
WEEK INTO THE WEEKEND.

&&

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

A SLOW APPROACHING COLD FRONT WILL CONTINUE TO DRAW LOW LEVEL
MOISTURE INTO THE AREA FROM NORTHERN BAJA TODAY. ANY SHOWER ACTIVITY
THROUGH THIS AFTERNOON WILL MAINLY STAY TO THE NORTH AND WEST OF THE
PHOENIX TERMINALS...BUT A FEW LIGHT SHOWERS MAY AFFECT KSDL. CIGS
FOR NOW SHOULD STAY ABOVE 8KT FEET THROUGH THE AFTERNOON HOURS...BUT
IF ANY SHOWERS DO OCCUR...CIGS WOULD TEMPORARILY DROP TO AROUND 5-6K
FEET. THE COLD FRONT AND AREA OF RAIN WILL APPROACH THE PHOENIX AREA
SOMETIME LATE THIS EVENING INTO TONIGHT...BUT CONFIDENCE IN THE
EXACT TIME OF ARRIVAL OF THE RAIN...LOWER CIGS...AND ANY RESTRICTED
VISIBILITIES IS STILL SOMEWHAT LOW.

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

MID LEVEL CIGS WILL GRADUALLY LOWER THIS MORNING AND EVENTUALLY DROP
TO MVFR BY AROUND NOON AFTER SOME STEADY RAIN MOVES IN. CONFIDENCE
IS FAIRLY HIGH THAT A BAND OF LIGHT TO MODERATE RAIN WILL AFFECT
SOUTHEAST CALIFORNIA AND PORTIONS OF SOUTHWEST ARIZONA THIS
AFTERNOON INTO THIS EVENING. MAY SEE SOME MVFR VISIBILITIES AT TIMES
DUE TO THE RAIN AND POTENTIALLY IFR CIGS BRIEFLY DEPENDING ON HOW
STEADY THE RAIN ENDS UP BEING. RAIN SHOULD DIMINISH AFTER 09Z
TONIGHT WITH GRADUALLY IMPROVING CIGS BY 12Z MONDAY MORNING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ020>021.
     FLOOD WATCH FROM MIDNIGHT TONIGHT THROUGH 8 PM MONDAY
     AZZ022>024.

CA...FLOOD WATCH UNTIL 12 PM MONDAY CAZ031>033.

&&

$$

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

DISCUSSION...AJ/LEINS
AVIATION...KUHLMAN
FIRE WEATHER...KUHLMAN







000
FXUS65 KPSR 012150
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
250 PM MST SUN MAR 1 2015

...WINTER WEATHER EVENT AFFECTING THE DESERT SOUTHWEST THROUGH LATE
MONDAY...

&&

.SYNOPSIS...
WIDESPREAD PRECIPITATION WILL EXPAND FROM SOUTHEAST CALIFORNIA INTO
ARIZONA TONIGHT AND SLOWLY SHIFT EASTWARD DURING THE DAY MONDAY.
PERIODS OF MODERATE TO HEAVY RAIN ARE ANTICIPATED...ESPECIALLY OVER
HIGHER TERRAIN AND FOOTHILL LOCATIONS. THERE WILL ALSO BE A SLIGHT
CHANCE OF THUNDERSTORMS DURING THE DAY MONDAY...MAINLY OVER PORTIONS
OF ARIZONA. COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS SYSTEM WITH
BELOW NORMAL READINGS EXPECTED MONDAY THROUGH MID WEEK. A RETURN TO
ABOVE NORMAL TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
REST OF TODAY THROUGH WEDNESDAY...
SHOWERS HAVE MOVED OVER OUR SOUTHEAST CALIFORNIA ZONES TODAY.
ISOLATED SHOWERS HAVE STARTED TO DEVELOP ELSEWHERE INCLUDING THE
PHOENIX AREA. MADE SOME EARLIER CHANGES TO THE FORECAST TO EXPAND
THE AREAL FLOOD WATCH TO SOUTHEAST CALIFORNIA. THE OTHER MAIN CHANGE
INCLUDED ANOTHER TIMING ADJUSTMENT FOR SOUTH-CENTRAL
ARIZONA...INCLUDING THE PHOENIX AREA...FOR A LATER START AND END. IN
SHORT...ANTICIPATE A SLOW RUNOFF RESPONSE TO THE RAINFALL BUT EXPECT
THERE WILL BE WASHES WITH SUFFICIENT FLOW TO CAUSE DANGEROUS
CONDITIONS AT SOME OF THE UNBRIDGED CROSSINGS. THERE WILL BE SOME
HIGHWAY DIPS AND OTHER LOW LYING AREAS THAT WILL SEE SOME INUNDATION
AS WELL. THE MAIN PRECIP MECHANISMS WITHIN THE LOW PRESSURE SYSTEM
ARE THE FRONTAL ZONE...CURRENTLY EXTENDING SOUTHWESTWARD FROM THE
MOHAVE DESERT...AND DYNAMICAL FORCING FROM SOME DIFFLUENCE RELATED
UPPER LEVEL DIVERGENCE...MAINLY NORTHWEST ARIZONA...AS WELL AS QG
FORCING FROM THE VORTICITY AND WARM AIR ADVECTION. THERE WILL ALSO
BE SOME INFLUENCE FROM THE RIGHT ENTRANCE REGION OF THE JET FOR
TOMORROW. THE FRONT IS ANTICIPATED TO MOVE THROUGH THE PHOENIX AREA
LATE MORNING/MIDDAY WITH PRECIP TRENDING DOWN FROM WEST TO EAST OVER
THE LOWER DESERTS OF ARIZONA IN MONDAY AFTERNOON...CONTINUING HIGHER
TERRAIN. THE MODELS ARE IN GENERALLY GOOD AGREEMENT ON THE TIMING
AND PLACEMENT OF THESE FEATURES THOUGH THE GFS IS A BIT MORE
GENEROUS WITH THE QG FORCING THAN NAM WHILE ECMWF IS A BIT SLOWER
WITH THE ONSET AND DEPARTURE OF PRECIP THAN NAM AND GFS. SEE THE
FLOOD WATCH FOR DETAILS ON THE TIMING AND PRECIP AMOUNTS. THE
UPSTREAM SYSTEM THAT WILL BE HELPING TO MOVE THIS MAIN ONE ALONG IS
CURRENTLY CENTERED NEAR THE ALASKA/CANADA BORDER. IT WILL RAPIDLY
MOVE DOWN THE COAST MONDAY AND THEN INTO NORTHWEST MEXICO TUESDAY.
MEANWHILE ANOTHER SHORT WAVE TRACKS THROUGH THE GREAT BASIN.
OUR FORECAST AREA WILL LARGELY BE BETWEEN THESE FEATURES BUT THEY
WILL CAUSE US TO KEEP A LINGERING SLIGHT CHANCE GOING...MAINLY OVER
SOUTH-CENTRAL ARIZONA. A MUCH WEAKER SHORT WAVE IS ADVERTISED TO
SLIDE DOWN FROM THE NORTH ON WEDNESDAY FOR SLIGHT CHANCES LIMITED TO
THE HIGHER TERRAIN OF SOUTH-CENTRAL AZ. SNOW LEVELS DROP TO NEAR
5000 FEET...INITIALLY OVER SOUTHEAST CALIFORNIA MONDAY MORNING THEN
EASTWARD TO SOUTH-CENTRAL ARIZONA BY EARLY MONDAY EVENING. THE
PRECIP WILL LARGELY BE OVER BY THE TIME THE SNOW LEVELS GET THAT LOW
AND THUS NO NOTABLE ACCUMULATIONS FOR OUR AREA...PERHAPS A DUSTING.
MADE A NUMBER OF TWEAKS TO THE POP/QPF GRIDS BUT NO MAJOR
ALTERATIONS FROM PREVIOUS PACKAGE. AS FOR TEMPERATURES...ANTICIPATE
LITTLE CHANGE OVER SOUTHEAST CALIFORNIA MONDAY SINCE THEY HAVE
ALREADY BEEN GETTING PRECIP. IT WILL BE MUCH COOLER THOUGH EAST OF
THE LOWER COLORADO RIVER VALLEY...ESPECIALLY SOUTH-CENTRAL ARIZONA.
IN FACT...PHOENIX AREA HIGH TEMP MONDAY MAY OCCUR BEFORE SUNRISE
WITH AFTERNOON PEAK IN THE 50S. WITH THE FOLLOW ON DISTURBANCES
TUESDAY AND WEDNESDAY...TEMPS WILL BE SLOW TO WARM UP THE FIRST HALF
OF THE WEEK.

FROM MID-WEEK ONWARD...RIDGING WILL TAKE HOLD ACROSS THE REGION AND
CONSEQUENTLY TEMPERATURES WILL ALSO CLIMB BACK ABOVE NORMAL BY LATE
WEEK INTO THE WEEKEND.

&&

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

A SLOW APPROACHING COLD FRONT WILL CONTINUE TO DRAW LOW LEVEL
MOISTURE INTO THE AREA FROM NORTHERN BAJA TODAY. ANY SHOWER ACTIVITY
THROUGH THIS AFTERNOON WILL MAINLY STAY TO THE NORTH AND WEST OF THE
PHOENIX TERMINALS...BUT A FEW LIGHT SHOWERS MAY AFFECT KSDL. CIGS
FOR NOW SHOULD STAY ABOVE 8KT FEET THROUGH THE AFTERNOON HOURS...BUT
IF ANY SHOWERS DO OCCUR...CIGS WOULD TEMPORARILY DROP TO AROUND 5-6K
FEET. THE COLD FRONT AND AREA OF RAIN WILL APPROACH THE PHOENIX AREA
SOMETIME LATE THIS EVENING INTO TONIGHT...BUT CONFIDENCE IN THE
EXACT TIME OF ARRIVAL OF THE RAIN...LOWER CIGS...AND ANY RESTRICTED
VISIBILITIES IS STILL SOMEWHAT LOW.

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

MID LEVEL CIGS WILL GRADUALLY LOWER THIS MORNING AND EVENTUALLY DROP
TO MVFR BY AROUND NOON AFTER SOME STEADY RAIN MOVES IN. CONFIDENCE
IS FAIRLY HIGH THAT A BAND OF LIGHT TO MODERATE RAIN WILL AFFECT
SOUTHEAST CALIFORNIA AND PORTIONS OF SOUTHWEST ARIZONA THIS
AFTERNOON INTO THIS EVENING. MAY SEE SOME MVFR VISIBILITIES AT TIMES
DUE TO THE RAIN AND POTENTIALLY IFR CIGS BRIEFLY DEPENDING ON HOW
STEADY THE RAIN ENDS UP BEING. RAIN SHOULD DIMINISH AFTER 09Z
TONIGHT WITH GRADUALLY IMPROVING CIGS BY 12Z MONDAY MORNING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ020>021.
     FLOOD WATCH FROM MIDNIGHT TONIGHT THROUGH 8 PM MONDAY
     AZZ022>024.

CA...FLOOD WATCH UNTIL 12 PM MONDAY CAZ031>033.

&&

$$

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

DISCUSSION...AJ/LEINS
AVIATION...KUHLMAN
FIRE WEATHER...KUHLMAN








000
FXUS65 KPSR 011641
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
940 AM MST SUN MAR 1 2015

...WINTER WEATHER EVENT ACROSS AFFECTING THE DESERT SOUTHWEST
THROUGH LATE MONDAY...

&&

.SYNOPSIS...
LOW PRESSURE WILL CONTINUE A SLOW APPROACH OF THE FORECAST
AREA...BRINGING MOISTURE INTO THE REGION ALONG WITH INCREASING
CHANCES OF SHOWERS TODAY AND MONDAY. PERIODS OF HEAVY RAIN ARE
POSSIBLE AT TIMES ESPECIALLY SUNDAY NIGHT THROUGH MONDAY AFTERNOON.
COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS STORM WITH BELOW NORMAL
READINGS EXPECTED MONDAY THROUGH MID WEEK. A RETURN TO ABOVE NORMAL
TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
UPPER LOW CENTERED JUST WEST OF SANTA BARBARA THIS MORNING WITH THE
POSITIVELY TILTED TROUGH BEGINNING TRENDING TOWARD A MORE NEUTRAL
ORIENTATION. ANOTHER SYSTEMS IS EVIDENT UPSTREAM CENTERED NEAR THE
ALASKA/CANADA BORDER. AS THE TROUGH SWINGS AROUND...CLOUDINESS OVER
THE SOUTHEASTERN HALF OF ARIZONA HAS BEEN SLOWLY THINNING AND
RETREATING NORTHWARD. THE ASSOCIATED FRONTAL ZONE IS QUITE EVIDENT
IN IR IMAGERY EXTENDING FROM THE MOHAVE DESERT SOUTHWESTWARD FOR A
GOOD DISTANCE OFFSHORE. THE 300 MB JET MAX WAS 110-120 KTS PER PLOT
DATA AND WAS LOCATED OVER THE MOHAVE DESERT. SOME SUBTLE DIFFLUENCE
WAS ALSO EVIDENT OVER PORTIONS OF NORTHERN ARIZONA WITH SHOWER
ACTIVITY AS A RESULT. 12Z NAM AND GFS INITIALIZED THIS DIVERGENCE
FAIRLY WELL. SHOWERS HAVE BEEN FILLING IN OVER FAR SOUTHEAST
CALIFORNIA AS DEEPER MOISTURE HAS FINALLY PUSHED OVER THE SOUTHWEST
CALIFORNIA MOUNTAINS. 12Z MODELS LOOK TO BE IN PRETTY GOOD AGREEMENT
ON THE EVOLUTION OF THE MAIN FEATURES AND AS A RESULT WITH THE MAIN
PATTERN OF STORM TOTAL QPF. GREATEST AMOUNT OF QPF WILL BE OVER THE
WESTERN MOGOLLON RIM AND YAVAPAI COUNTY AND PORTIONS OF MOHAVE
COUNTY...WITH NORTHERN PORTIONS OF OUR FORECAST AREA ON THE SOUTHERN
END OF THAT...PLUS A SECONDARY MAXIMUM NEAR AND WEST OF THE LOWER
COLORADO RIVER VALLEY WHICH WAS SEEN IN PREVIOUS RUNS. FOR
SOUTH-CENTRAL ARIZONA...INCLUDING METRO PHOENIX...ANTICIPATE ONLY
ISOLATED LIGHT SHOWERS REST OF TODAY THROUGH THE EVENING BEFORE RAIN
BEGINS IN EARNEST EARLY MONDAY AND TAPERS OFF MONDAY EVENING. MIGHT
EVEN NEED TO TRIM POPS EVEN MORE FOR TODAY. FURTHER WEST...THE MORE
SIGNIFICANT PRECIP STARTS TODAY. GIVEN THE EAST-WEST TIMING
DIFFERENCES...CONTEMPLATING MAKING ADJUSTMENTS TO THE FLOOD WATCH TO
DELAY THE ONSET FOR SOUTH-CENTRAL ARIZONA BY AT LEAST 6 HOURS. ALSO
CONTEMPLATING EXPANSION OF THE WATCH TO THE LOWER COLORADO RIVER
INTO SOUTHEAST CALIFORNIA. MAIN THREAT AREA FOR FLOODING WILL BE
HIGHER TERRAIN AND NEARBY FOOTHILL AREAS. MORE LATER.

&&

.PREVIOUS DISCUSSION ISSUED 243 AM MST/143 AM PST...
EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SLOWLY RETROGRADING AREA
OF LOW PRESSURE OFF THE SOUTHERN CALIFORNIA COAST...WITH QUITE A BIT
OF MID AND HIGH CLOUD COVER DEVELOPING DOWNWIND OF THE COASTAL
MOUNTAINS ALONG THE LOWER COLORADO RIVER VALLEY. FINALLY AFTER MUCH
ANTICIPATION...PRECIP APPEARS TO BE DEVELOPING ACROSS THE WESTERN
PORTIONS OF THE FORECAST AREA AS RADAR RETURNS HAVE INCREASED
SUBSTANTIALLY SINCE 07Z. MOST THE THE PRECIP THAT IS REACHING THE
GROUND IS STILL CONFINED TO THE HIGHER TERRAIN NORTH OF PHOENIX BUT
NONETHELESS IT`S A GOOD SIGN THAT THE ATMOSPHERE IS RESPONDING TO
THE SUBTROPICAL MOISTURE THAT`S BEING ADVECTED INTO THE AREA.

LOW PRESSURE WILL CONTINUE ITS SLOW TREK DOWN THE CALIFORNIA COAST
TODAY...EVENTUALLY STALLING OUT WEST OF SAN DIEGO THIS AFTERNOON. IN
THE MEANTIME IT WILL CONTINUE TAPPING INTO THE ANOMALOUSLY MOIST
SUBTROPICAL PLUME OF MOISTURE THAT IS EVIDENT ON WATER VAPOR IMAGERY
SOUTH OF THE BAJA SPUR. RAIN SHADOWING DOWNWIND OF THE COASTAL
MOUNTAINS WILL PRECLUDE WIDESPREAD PRECIP FROM DEVELOPING THIS
MORNING...BUT EVENTUALLY ENOUGH MOISTURE WILL BUILD UP ACROSS
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA THAT SHOWERS WILL BECOME
MORE WIDESPREAD IN NATURE. THE INHERITED FORECAST ALREADY DEPICTED
THIS SCENARIO AND I ONLY MADE MINOR CHANGES TO THE FORECAST FOR THE
WESTERN FORECAST AREA. TO THE EAST HOWEVER...IT STILL LOOKS LIKE
PRECIP WILL BE SLOW TO DEVELOP AROUND THE PHOENIX AREA...POSSIBLY
HOLDING OFF UNTIL SUNDAY EVENING/EARLY MONDAY MORNING. LATEST NAEFS
GUIDANCE AND THE PAST 2-3 RUNS OF THE SREF INDICATE THE BEST CHANCE
OF PRECIP WILL COME AFTER 00Z TONIGHT AND THUS I TRIMMED POPS A BIT
FOR TODAY. ONLY THINKING WE WILL SEE 20-30 PERCENT CHANCES AROUND
THE METRO...CERTAINLY LOOKING AT HIGHER CHANCES IN THE FOOTHILL
LOCATIONS NORTH/WEST/EAST OF PHOENIX BUT IT LOOKS MORE AND MORE
LIKELY THAT THE MORE WIDESPREAD RAIN WILL BE DELAYED A BIT.

THE QUASI-STATIONARY LOW WEST OF SAN DIEGO WILL GET KICKED THROUGH
THE AREA TOMORROW BY A RAPIDLY APPROACHING SECONDARY TROUGH MOVING
THROUGH NEVADA. THIS WILL BRING MORE WIDESPREAD PRECIP THROUGH THE
ENTIRE FORECAST AREA MONDAY MORNING/MONDAY AFTERNOON...WITH RAPID
CLEARING FROM WEST TO EAST MONDAY NIGHT. WHILE 500MB TEMPERATURE
FORECASTS HAVE RISEN OVER THE PAST FEW DAYS...BUFR SOUNDINGS
INDICATE ENOUGH INSTABILITY POTENTIAL COINCIDENT WITH THE PASSAGE OF
THE TROUGH TO WARRANT AT LEAST A SLIGHT CHANCE OF THUNDER. ONCE THE
TROUGH AXIS MOVES INTO NEW MEXICO MONDAY NIGHT...PRECIP CHANCES /AND
THE POTENTIAL FOR THUNDER/ WILL DROP CONSIDERABLY. AS FOR STORM
TOTAL PRECIP VALUES...ENSEMBLE MEAN IS AROUND 0.75 INCHES ALONG AND
NORTH OF I-10 WITH CLOSER TO 1-1.5 INCHES IN THE OROGRAPHICALLY
FAVORED UPSLOPE AREAS ACROSS NORTHERN LA PAZ COUNTY TO
WICKENBURG...CAVE CREEK...AND THE MOUNTAINS OF SOUTHERN GILA COUNTY.
MADE SOME SLIGHT ADJUSTMENTS TO STORM TOTAL QPF BASED ON THE SLOWER
ARRIVAL OF THE HEAVIER PRECIP BUT STILL ENOUGH TO KEEP THE FLOOD
WATCH INTACT.

THE IMPACTS ASSOCIATED WITH THE SECONDARY TROUGH ON TUESDAY HAVE
BEEN THE SOURCE OF MUCH DEBATE DUE TO VARYING MODEL SOLUTIONS...AND
INDIVIDUAL ENSEMBLE MEMBERS ARE STILL ALL OVER THE MAP THIS MORNING.
NO DOUBT THERE WILL BE SOME LINGERING MOISTURE IN THE AREA...THE
QUESTION IS IF THERE WILL BE ENOUGH FORCING WITH THIS SECONDARY
TROUGH TO TRIGGER SHOWERS ACROSS THE AREA. FELT IT PRUDENT TO KEEP
THE CHANCE OF PRECIP LINGERING ACROSS THE EASTERN HALF OF THE
FORECAST AREA ON TUESDAY ALTHOUGH MOST OF THE SHOWERS SHOULD BE TO
THE NORTH/EAST OF PHOENIX. 00Z DETERMINISTIC MODELS HAVE TRENDED
DRIER ON TUESDAY...WILL NEED TO SEE IF THIS TREND CONTINUES AND IF
THE ENSEMBLES PICK UP ON THIS DRIER SOLUTION.

FROM MID-WEEK ONWARD...RIDGING WILL TAKE HOLD ACROSS THE REGION AND
CONSEQUENTLY TEMPERATURES WILL ALSO CLIMB BACK ABOVE NORMAL BY LATE
WEEK INTO THE WEEKEND.

&&

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

A SLOW APPROACHING COLD FRONT WILL CONTINUE TO DRAW LOW LEVEL
MOISTURE INTO THE AREA FROM NORTHERN BAJA TODAY. ANY SHOWER ACTIVITY
THROUGH THIS AFTERNOON WILL MAINLY STAY TO THE NORTH AND WEST OF THE
PHOENIX TERMINALS...BUT A FEW LIGHT SHOWERS MAY AFFECT KSDL. CIGS
FOR NOW SHOULD STAY ABOVE 8KT FEET THROUGH THE AFTERNOON HOURS...BUT
IF ANY SHOWERS DO OCCUR...CIGS WOULD TEMPORARILY DROP TO AROUND 5-6K
FEET. THE COLD FRONT AND AREA OF RAIN WILL APPROACH THE PHOENIX AREA
SOMETIME LATE THIS EVENING INTO TONIGHT...BUT CONFIDENCE IN THE
EXACT TIME OF ARRIVAL OF THE RAIN...LOWER CIGS...AND ANY RESTRICTED
VISIBILITIES IS STILL SOMEWHAT LOW.

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

MID LEVEL CIGS WILL GRADUALLY LOWER THIS MORNING AND EVENTUALLY DROP
TO MVFR BY AROUND NOON AFTER SOME STEADY RAIN MOVES IN. CONFIDENCE
IS FAIRLY HIGH THAT A BAND OF LIGHT TO MODERATE RAIN WILL AFFECT
SOUTHEAST CALIFORNIA AND PORTIONS OF SOUTHWEST ARIZONA THIS
AFTERNOON INTO THIS EVENING. MAY SEE SOME MVFR VISIBILITIES AT TIMES
DUE TO THE RAIN AND POTENTIALLY IFR CIGS BRIEFLY DEPENDING ON HOW
STEADY THE RAIN ENDS UP BEING. RAIN SHOULD DIMINISH AFTER 09Z
TONIGHT WITH GRADUALLY IMPROVING CIGS BY 12Z MONDAY MORNING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ021>024.

CA...NONE.

&&

$$

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

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








000
FXUS65 KPSR 011641
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
940 AM MST SUN MAR 1 2015

...WINTER WEATHER EVENT ACROSS AFFECTING THE DESERT SOUTHWEST
THROUGH LATE MONDAY...

&&

.SYNOPSIS...
LOW PRESSURE WILL CONTINUE A SLOW APPROACH OF THE FORECAST
AREA...BRINGING MOISTURE INTO THE REGION ALONG WITH INCREASING
CHANCES OF SHOWERS TODAY AND MONDAY. PERIODS OF HEAVY RAIN ARE
POSSIBLE AT TIMES ESPECIALLY SUNDAY NIGHT THROUGH MONDAY AFTERNOON.
COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS STORM WITH BELOW NORMAL
READINGS EXPECTED MONDAY THROUGH MID WEEK. A RETURN TO ABOVE NORMAL
TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
UPPER LOW CENTERED JUST WEST OF SANTA BARBARA THIS MORNING WITH THE
POSITIVELY TILTED TROUGH BEGINNING TRENDING TOWARD A MORE NEUTRAL
ORIENTATION. ANOTHER SYSTEMS IS EVIDENT UPSTREAM CENTERED NEAR THE
ALASKA/CANADA BORDER. AS THE TROUGH SWINGS AROUND...CLOUDINESS OVER
THE SOUTHEASTERN HALF OF ARIZONA HAS BEEN SLOWLY THINNING AND
RETREATING NORTHWARD. THE ASSOCIATED FRONTAL ZONE IS QUITE EVIDENT
IN IR IMAGERY EXTENDING FROM THE MOHAVE DESERT SOUTHWESTWARD FOR A
GOOD DISTANCE OFFSHORE. THE 300 MB JET MAX WAS 110-120 KTS PER PLOT
DATA AND WAS LOCATED OVER THE MOHAVE DESERT. SOME SUBTLE DIFFLUENCE
WAS ALSO EVIDENT OVER PORTIONS OF NORTHERN ARIZONA WITH SHOWER
ACTIVITY AS A RESULT. 12Z NAM AND GFS INITIALIZED THIS DIVERGENCE
FAIRLY WELL. SHOWERS HAVE BEEN FILLING IN OVER FAR SOUTHEAST
CALIFORNIA AS DEEPER MOISTURE HAS FINALLY PUSHED OVER THE SOUTHWEST
CALIFORNIA MOUNTAINS. 12Z MODELS LOOK TO BE IN PRETTY GOOD AGREEMENT
ON THE EVOLUTION OF THE MAIN FEATURES AND AS A RESULT WITH THE MAIN
PATTERN OF STORM TOTAL QPF. GREATEST AMOUNT OF QPF WILL BE OVER THE
WESTERN MOGOLLON RIM AND YAVAPAI COUNTY AND PORTIONS OF MOHAVE
COUNTY...WITH NORTHERN PORTIONS OF OUR FORECAST AREA ON THE SOUTHERN
END OF THAT...PLUS A SECONDARY MAXIMUM NEAR AND WEST OF THE LOWER
COLORADO RIVER VALLEY WHICH WAS SEEN IN PREVIOUS RUNS. FOR
SOUTH-CENTRAL ARIZONA...INCLUDING METRO PHOENIX...ANTICIPATE ONLY
ISOLATED LIGHT SHOWERS REST OF TODAY THROUGH THE EVENING BEFORE RAIN
BEGINS IN EARNEST EARLY MONDAY AND TAPERS OFF MONDAY EVENING. MIGHT
EVEN NEED TO TRIM POPS EVEN MORE FOR TODAY. FURTHER WEST...THE MORE
SIGNIFICANT PRECIP STARTS TODAY. GIVEN THE EAST-WEST TIMING
DIFFERENCES...CONTEMPLATING MAKING ADJUSTMENTS TO THE FLOOD WATCH TO
DELAY THE ONSET FOR SOUTH-CENTRAL ARIZONA BY AT LEAST 6 HOURS. ALSO
CONTEMPLATING EXPANSION OF THE WATCH TO THE LOWER COLORADO RIVER
INTO SOUTHEAST CALIFORNIA. MAIN THREAT AREA FOR FLOODING WILL BE
HIGHER TERRAIN AND NEARBY FOOTHILL AREAS. MORE LATER.

&&

.PREVIOUS DISCUSSION ISSUED 243 AM MST/143 AM PST...
EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SLOWLY RETROGRADING AREA
OF LOW PRESSURE OFF THE SOUTHERN CALIFORNIA COAST...WITH QUITE A BIT
OF MID AND HIGH CLOUD COVER DEVELOPING DOWNWIND OF THE COASTAL
MOUNTAINS ALONG THE LOWER COLORADO RIVER VALLEY. FINALLY AFTER MUCH
ANTICIPATION...PRECIP APPEARS TO BE DEVELOPING ACROSS THE WESTERN
PORTIONS OF THE FORECAST AREA AS RADAR RETURNS HAVE INCREASED
SUBSTANTIALLY SINCE 07Z. MOST THE THE PRECIP THAT IS REACHING THE
GROUND IS STILL CONFINED TO THE HIGHER TERRAIN NORTH OF PHOENIX BUT
NONETHELESS IT`S A GOOD SIGN THAT THE ATMOSPHERE IS RESPONDING TO
THE SUBTROPICAL MOISTURE THAT`S BEING ADVECTED INTO THE AREA.

LOW PRESSURE WILL CONTINUE ITS SLOW TREK DOWN THE CALIFORNIA COAST
TODAY...EVENTUALLY STALLING OUT WEST OF SAN DIEGO THIS AFTERNOON. IN
THE MEANTIME IT WILL CONTINUE TAPPING INTO THE ANOMALOUSLY MOIST
SUBTROPICAL PLUME OF MOISTURE THAT IS EVIDENT ON WATER VAPOR IMAGERY
SOUTH OF THE BAJA SPUR. RAIN SHADOWING DOWNWIND OF THE COASTAL
MOUNTAINS WILL PRECLUDE WIDESPREAD PRECIP FROM DEVELOPING THIS
MORNING...BUT EVENTUALLY ENOUGH MOISTURE WILL BUILD UP ACROSS
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA THAT SHOWERS WILL BECOME
MORE WIDESPREAD IN NATURE. THE INHERITED FORECAST ALREADY DEPICTED
THIS SCENARIO AND I ONLY MADE MINOR CHANGES TO THE FORECAST FOR THE
WESTERN FORECAST AREA. TO THE EAST HOWEVER...IT STILL LOOKS LIKE
PRECIP WILL BE SLOW TO DEVELOP AROUND THE PHOENIX AREA...POSSIBLY
HOLDING OFF UNTIL SUNDAY EVENING/EARLY MONDAY MORNING. LATEST NAEFS
GUIDANCE AND THE PAST 2-3 RUNS OF THE SREF INDICATE THE BEST CHANCE
OF PRECIP WILL COME AFTER 00Z TONIGHT AND THUS I TRIMMED POPS A BIT
FOR TODAY. ONLY THINKING WE WILL SEE 20-30 PERCENT CHANCES AROUND
THE METRO...CERTAINLY LOOKING AT HIGHER CHANCES IN THE FOOTHILL
LOCATIONS NORTH/WEST/EAST OF PHOENIX BUT IT LOOKS MORE AND MORE
LIKELY THAT THE MORE WIDESPREAD RAIN WILL BE DELAYED A BIT.

THE QUASI-STATIONARY LOW WEST OF SAN DIEGO WILL GET KICKED THROUGH
THE AREA TOMORROW BY A RAPIDLY APPROACHING SECONDARY TROUGH MOVING
THROUGH NEVADA. THIS WILL BRING MORE WIDESPREAD PRECIP THROUGH THE
ENTIRE FORECAST AREA MONDAY MORNING/MONDAY AFTERNOON...WITH RAPID
CLEARING FROM WEST TO EAST MONDAY NIGHT. WHILE 500MB TEMPERATURE
FORECASTS HAVE RISEN OVER THE PAST FEW DAYS...BUFR SOUNDINGS
INDICATE ENOUGH INSTABILITY POTENTIAL COINCIDENT WITH THE PASSAGE OF
THE TROUGH TO WARRANT AT LEAST A SLIGHT CHANCE OF THUNDER. ONCE THE
TROUGH AXIS MOVES INTO NEW MEXICO MONDAY NIGHT...PRECIP CHANCES /AND
THE POTENTIAL FOR THUNDER/ WILL DROP CONSIDERABLY. AS FOR STORM
TOTAL PRECIP VALUES...ENSEMBLE MEAN IS AROUND 0.75 INCHES ALONG AND
NORTH OF I-10 WITH CLOSER TO 1-1.5 INCHES IN THE OROGRAPHICALLY
FAVORED UPSLOPE AREAS ACROSS NORTHERN LA PAZ COUNTY TO
WICKENBURG...CAVE CREEK...AND THE MOUNTAINS OF SOUTHERN GILA COUNTY.
MADE SOME SLIGHT ADJUSTMENTS TO STORM TOTAL QPF BASED ON THE SLOWER
ARRIVAL OF THE HEAVIER PRECIP BUT STILL ENOUGH TO KEEP THE FLOOD
WATCH INTACT.

THE IMPACTS ASSOCIATED WITH THE SECONDARY TROUGH ON TUESDAY HAVE
BEEN THE SOURCE OF MUCH DEBATE DUE TO VARYING MODEL SOLUTIONS...AND
INDIVIDUAL ENSEMBLE MEMBERS ARE STILL ALL OVER THE MAP THIS MORNING.
NO DOUBT THERE WILL BE SOME LINGERING MOISTURE IN THE AREA...THE
QUESTION IS IF THERE WILL BE ENOUGH FORCING WITH THIS SECONDARY
TROUGH TO TRIGGER SHOWERS ACROSS THE AREA. FELT IT PRUDENT TO KEEP
THE CHANCE OF PRECIP LINGERING ACROSS THE EASTERN HALF OF THE
FORECAST AREA ON TUESDAY ALTHOUGH MOST OF THE SHOWERS SHOULD BE TO
THE NORTH/EAST OF PHOENIX. 00Z DETERMINISTIC MODELS HAVE TRENDED
DRIER ON TUESDAY...WILL NEED TO SEE IF THIS TREND CONTINUES AND IF
THE ENSEMBLES PICK UP ON THIS DRIER SOLUTION.

FROM MID-WEEK ONWARD...RIDGING WILL TAKE HOLD ACROSS THE REGION AND
CONSEQUENTLY TEMPERATURES WILL ALSO CLIMB BACK ABOVE NORMAL BY LATE
WEEK INTO THE WEEKEND.

&&

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

A SLOW APPROACHING COLD FRONT WILL CONTINUE TO DRAW LOW LEVEL
MOISTURE INTO THE AREA FROM NORTHERN BAJA TODAY. ANY SHOWER ACTIVITY
THROUGH THIS AFTERNOON WILL MAINLY STAY TO THE NORTH AND WEST OF THE
PHOENIX TERMINALS...BUT A FEW LIGHT SHOWERS MAY AFFECT KSDL. CIGS
FOR NOW SHOULD STAY ABOVE 8KT FEET THROUGH THE AFTERNOON HOURS...BUT
IF ANY SHOWERS DO OCCUR...CIGS WOULD TEMPORARILY DROP TO AROUND 5-6K
FEET. THE COLD FRONT AND AREA OF RAIN WILL APPROACH THE PHOENIX AREA
SOMETIME LATE THIS EVENING INTO TONIGHT...BUT CONFIDENCE IN THE
EXACT TIME OF ARRIVAL OF THE RAIN...LOWER CIGS...AND ANY RESTRICTED
VISIBILITIES IS STILL SOMEWHAT LOW.

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

MID LEVEL CIGS WILL GRADUALLY LOWER THIS MORNING AND EVENTUALLY DROP
TO MVFR BY AROUND NOON AFTER SOME STEADY RAIN MOVES IN. CONFIDENCE
IS FAIRLY HIGH THAT A BAND OF LIGHT TO MODERATE RAIN WILL AFFECT
SOUTHEAST CALIFORNIA AND PORTIONS OF SOUTHWEST ARIZONA THIS
AFTERNOON INTO THIS EVENING. MAY SEE SOME MVFR VISIBILITIES AT TIMES
DUE TO THE RAIN AND POTENTIALLY IFR CIGS BRIEFLY DEPENDING ON HOW
STEADY THE RAIN ENDS UP BEING. RAIN SHOULD DIMINISH AFTER 09Z
TONIGHT WITH GRADUALLY IMPROVING CIGS BY 12Z MONDAY MORNING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ021>024.

CA...NONE.

&&

$$

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

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







000
FXUS65 KPSR 011641
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
940 AM MST SUN MAR 1 2015

...WINTER WEATHER EVENT ACROSS AFFECTING THE DESERT SOUTHWEST
THROUGH LATE MONDAY...

&&

.SYNOPSIS...
LOW PRESSURE WILL CONTINUE A SLOW APPROACH OF THE FORECAST
AREA...BRINGING MOISTURE INTO THE REGION ALONG WITH INCREASING
CHANCES OF SHOWERS TODAY AND MONDAY. PERIODS OF HEAVY RAIN ARE
POSSIBLE AT TIMES ESPECIALLY SUNDAY NIGHT THROUGH MONDAY AFTERNOON.
COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS STORM WITH BELOW NORMAL
READINGS EXPECTED MONDAY THROUGH MID WEEK. A RETURN TO ABOVE NORMAL
TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
UPPER LOW CENTERED JUST WEST OF SANTA BARBARA THIS MORNING WITH THE
POSITIVELY TILTED TROUGH BEGINNING TRENDING TOWARD A MORE NEUTRAL
ORIENTATION. ANOTHER SYSTEMS IS EVIDENT UPSTREAM CENTERED NEAR THE
ALASKA/CANADA BORDER. AS THE TROUGH SWINGS AROUND...CLOUDINESS OVER
THE SOUTHEASTERN HALF OF ARIZONA HAS BEEN SLOWLY THINNING AND
RETREATING NORTHWARD. THE ASSOCIATED FRONTAL ZONE IS QUITE EVIDENT
IN IR IMAGERY EXTENDING FROM THE MOHAVE DESERT SOUTHWESTWARD FOR A
GOOD DISTANCE OFFSHORE. THE 300 MB JET MAX WAS 110-120 KTS PER PLOT
DATA AND WAS LOCATED OVER THE MOHAVE DESERT. SOME SUBTLE DIFFLUENCE
WAS ALSO EVIDENT OVER PORTIONS OF NORTHERN ARIZONA WITH SHOWER
ACTIVITY AS A RESULT. 12Z NAM AND GFS INITIALIZED THIS DIVERGENCE
FAIRLY WELL. SHOWERS HAVE BEEN FILLING IN OVER FAR SOUTHEAST
CALIFORNIA AS DEEPER MOISTURE HAS FINALLY PUSHED OVER THE SOUTHWEST
CALIFORNIA MOUNTAINS. 12Z MODELS LOOK TO BE IN PRETTY GOOD AGREEMENT
ON THE EVOLUTION OF THE MAIN FEATURES AND AS A RESULT WITH THE MAIN
PATTERN OF STORM TOTAL QPF. GREATEST AMOUNT OF QPF WILL BE OVER THE
WESTERN MOGOLLON RIM AND YAVAPAI COUNTY AND PORTIONS OF MOHAVE
COUNTY...WITH NORTHERN PORTIONS OF OUR FORECAST AREA ON THE SOUTHERN
END OF THAT...PLUS A SECONDARY MAXIMUM NEAR AND WEST OF THE LOWER
COLORADO RIVER VALLEY WHICH WAS SEEN IN PREVIOUS RUNS. FOR
SOUTH-CENTRAL ARIZONA...INCLUDING METRO PHOENIX...ANTICIPATE ONLY
ISOLATED LIGHT SHOWERS REST OF TODAY THROUGH THE EVENING BEFORE RAIN
BEGINS IN EARNEST EARLY MONDAY AND TAPERS OFF MONDAY EVENING. MIGHT
EVEN NEED TO TRIM POPS EVEN MORE FOR TODAY. FURTHER WEST...THE MORE
SIGNIFICANT PRECIP STARTS TODAY. GIVEN THE EAST-WEST TIMING
DIFFERENCES...CONTEMPLATING MAKING ADJUSTMENTS TO THE FLOOD WATCH TO
DELAY THE ONSET FOR SOUTH-CENTRAL ARIZONA BY AT LEAST 6 HOURS. ALSO
CONTEMPLATING EXPANSION OF THE WATCH TO THE LOWER COLORADO RIVER
INTO SOUTHEAST CALIFORNIA. MAIN THREAT AREA FOR FLOODING WILL BE
HIGHER TERRAIN AND NEARBY FOOTHILL AREAS. MORE LATER.

&&

.PREVIOUS DISCUSSION ISSUED 243 AM MST/143 AM PST...
EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SLOWLY RETROGRADING AREA
OF LOW PRESSURE OFF THE SOUTHERN CALIFORNIA COAST...WITH QUITE A BIT
OF MID AND HIGH CLOUD COVER DEVELOPING DOWNWIND OF THE COASTAL
MOUNTAINS ALONG THE LOWER COLORADO RIVER VALLEY. FINALLY AFTER MUCH
ANTICIPATION...PRECIP APPEARS TO BE DEVELOPING ACROSS THE WESTERN
PORTIONS OF THE FORECAST AREA AS RADAR RETURNS HAVE INCREASED
SUBSTANTIALLY SINCE 07Z. MOST THE THE PRECIP THAT IS REACHING THE
GROUND IS STILL CONFINED TO THE HIGHER TERRAIN NORTH OF PHOENIX BUT
NONETHELESS IT`S A GOOD SIGN THAT THE ATMOSPHERE IS RESPONDING TO
THE SUBTROPICAL MOISTURE THAT`S BEING ADVECTED INTO THE AREA.

LOW PRESSURE WILL CONTINUE ITS SLOW TREK DOWN THE CALIFORNIA COAST
TODAY...EVENTUALLY STALLING OUT WEST OF SAN DIEGO THIS AFTERNOON. IN
THE MEANTIME IT WILL CONTINUE TAPPING INTO THE ANOMALOUSLY MOIST
SUBTROPICAL PLUME OF MOISTURE THAT IS EVIDENT ON WATER VAPOR IMAGERY
SOUTH OF THE BAJA SPUR. RAIN SHADOWING DOWNWIND OF THE COASTAL
MOUNTAINS WILL PRECLUDE WIDESPREAD PRECIP FROM DEVELOPING THIS
MORNING...BUT EVENTUALLY ENOUGH MOISTURE WILL BUILD UP ACROSS
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA THAT SHOWERS WILL BECOME
MORE WIDESPREAD IN NATURE. THE INHERITED FORECAST ALREADY DEPICTED
THIS SCENARIO AND I ONLY MADE MINOR CHANGES TO THE FORECAST FOR THE
WESTERN FORECAST AREA. TO THE EAST HOWEVER...IT STILL LOOKS LIKE
PRECIP WILL BE SLOW TO DEVELOP AROUND THE PHOENIX AREA...POSSIBLY
HOLDING OFF UNTIL SUNDAY EVENING/EARLY MONDAY MORNING. LATEST NAEFS
GUIDANCE AND THE PAST 2-3 RUNS OF THE SREF INDICATE THE BEST CHANCE
OF PRECIP WILL COME AFTER 00Z TONIGHT AND THUS I TRIMMED POPS A BIT
FOR TODAY. ONLY THINKING WE WILL SEE 20-30 PERCENT CHANCES AROUND
THE METRO...CERTAINLY LOOKING AT HIGHER CHANCES IN THE FOOTHILL
LOCATIONS NORTH/WEST/EAST OF PHOENIX BUT IT LOOKS MORE AND MORE
LIKELY THAT THE MORE WIDESPREAD RAIN WILL BE DELAYED A BIT.

THE QUASI-STATIONARY LOW WEST OF SAN DIEGO WILL GET KICKED THROUGH
THE AREA TOMORROW BY A RAPIDLY APPROACHING SECONDARY TROUGH MOVING
THROUGH NEVADA. THIS WILL BRING MORE WIDESPREAD PRECIP THROUGH THE
ENTIRE FORECAST AREA MONDAY MORNING/MONDAY AFTERNOON...WITH RAPID
CLEARING FROM WEST TO EAST MONDAY NIGHT. WHILE 500MB TEMPERATURE
FORECASTS HAVE RISEN OVER THE PAST FEW DAYS...BUFR SOUNDINGS
INDICATE ENOUGH INSTABILITY POTENTIAL COINCIDENT WITH THE PASSAGE OF
THE TROUGH TO WARRANT AT LEAST A SLIGHT CHANCE OF THUNDER. ONCE THE
TROUGH AXIS MOVES INTO NEW MEXICO MONDAY NIGHT...PRECIP CHANCES /AND
THE POTENTIAL FOR THUNDER/ WILL DROP CONSIDERABLY. AS FOR STORM
TOTAL PRECIP VALUES...ENSEMBLE MEAN IS AROUND 0.75 INCHES ALONG AND
NORTH OF I-10 WITH CLOSER TO 1-1.5 INCHES IN THE OROGRAPHICALLY
FAVORED UPSLOPE AREAS ACROSS NORTHERN LA PAZ COUNTY TO
WICKENBURG...CAVE CREEK...AND THE MOUNTAINS OF SOUTHERN GILA COUNTY.
MADE SOME SLIGHT ADJUSTMENTS TO STORM TOTAL QPF BASED ON THE SLOWER
ARRIVAL OF THE HEAVIER PRECIP BUT STILL ENOUGH TO KEEP THE FLOOD
WATCH INTACT.

THE IMPACTS ASSOCIATED WITH THE SECONDARY TROUGH ON TUESDAY HAVE
BEEN THE SOURCE OF MUCH DEBATE DUE TO VARYING MODEL SOLUTIONS...AND
INDIVIDUAL ENSEMBLE MEMBERS ARE STILL ALL OVER THE MAP THIS MORNING.
NO DOUBT THERE WILL BE SOME LINGERING MOISTURE IN THE AREA...THE
QUESTION IS IF THERE WILL BE ENOUGH FORCING WITH THIS SECONDARY
TROUGH TO TRIGGER SHOWERS ACROSS THE AREA. FELT IT PRUDENT TO KEEP
THE CHANCE OF PRECIP LINGERING ACROSS THE EASTERN HALF OF THE
FORECAST AREA ON TUESDAY ALTHOUGH MOST OF THE SHOWERS SHOULD BE TO
THE NORTH/EAST OF PHOENIX. 00Z DETERMINISTIC MODELS HAVE TRENDED
DRIER ON TUESDAY...WILL NEED TO SEE IF THIS TREND CONTINUES AND IF
THE ENSEMBLES PICK UP ON THIS DRIER SOLUTION.

FROM MID-WEEK ONWARD...RIDGING WILL TAKE HOLD ACROSS THE REGION AND
CONSEQUENTLY TEMPERATURES WILL ALSO CLIMB BACK ABOVE NORMAL BY LATE
WEEK INTO THE WEEKEND.

&&

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

A SLOW APPROACHING COLD FRONT WILL CONTINUE TO DRAW LOW LEVEL
MOISTURE INTO THE AREA FROM NORTHERN BAJA TODAY. ANY SHOWER ACTIVITY
THROUGH THIS AFTERNOON WILL MAINLY STAY TO THE NORTH AND WEST OF THE
PHOENIX TERMINALS...BUT A FEW LIGHT SHOWERS MAY AFFECT KSDL. CIGS
FOR NOW SHOULD STAY ABOVE 8KT FEET THROUGH THE AFTERNOON HOURS...BUT
IF ANY SHOWERS DO OCCUR...CIGS WOULD TEMPORARILY DROP TO AROUND 5-6K
FEET. THE COLD FRONT AND AREA OF RAIN WILL APPROACH THE PHOENIX AREA
SOMETIME LATE THIS EVENING INTO TONIGHT...BUT CONFIDENCE IN THE
EXACT TIME OF ARRIVAL OF THE RAIN...LOWER CIGS...AND ANY RESTRICTED
VISIBILITIES IS STILL SOMEWHAT LOW.

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

MID LEVEL CIGS WILL GRADUALLY LOWER THIS MORNING AND EVENTUALLY DROP
TO MVFR BY AROUND NOON AFTER SOME STEADY RAIN MOVES IN. CONFIDENCE
IS FAIRLY HIGH THAT A BAND OF LIGHT TO MODERATE RAIN WILL AFFECT
SOUTHEAST CALIFORNIA AND PORTIONS OF SOUTHWEST ARIZONA THIS
AFTERNOON INTO THIS EVENING. MAY SEE SOME MVFR VISIBILITIES AT TIMES
DUE TO THE RAIN AND POTENTIALLY IFR CIGS BRIEFLY DEPENDING ON HOW
STEADY THE RAIN ENDS UP BEING. RAIN SHOULD DIMINISH AFTER 09Z
TONIGHT WITH GRADUALLY IMPROVING CIGS BY 12Z MONDAY MORNING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ021>024.

CA...NONE.

&&

$$

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

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








000
FXUS65 KPSR 011641
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
940 AM MST SUN MAR 1 2015

...WINTER WEATHER EVENT ACROSS AFFECTING THE DESERT SOUTHWEST
THROUGH LATE MONDAY...

&&

.SYNOPSIS...
LOW PRESSURE WILL CONTINUE A SLOW APPROACH OF THE FORECAST
AREA...BRINGING MOISTURE INTO THE REGION ALONG WITH INCREASING
CHANCES OF SHOWERS TODAY AND MONDAY. PERIODS OF HEAVY RAIN ARE
POSSIBLE AT TIMES ESPECIALLY SUNDAY NIGHT THROUGH MONDAY AFTERNOON.
COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS STORM WITH BELOW NORMAL
READINGS EXPECTED MONDAY THROUGH MID WEEK. A RETURN TO ABOVE NORMAL
TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
UPPER LOW CENTERED JUST WEST OF SANTA BARBARA THIS MORNING WITH THE
POSITIVELY TILTED TROUGH BEGINNING TRENDING TOWARD A MORE NEUTRAL
ORIENTATION. ANOTHER SYSTEMS IS EVIDENT UPSTREAM CENTERED NEAR THE
ALASKA/CANADA BORDER. AS THE TROUGH SWINGS AROUND...CLOUDINESS OVER
THE SOUTHEASTERN HALF OF ARIZONA HAS BEEN SLOWLY THINNING AND
RETREATING NORTHWARD. THE ASSOCIATED FRONTAL ZONE IS QUITE EVIDENT
IN IR IMAGERY EXTENDING FROM THE MOHAVE DESERT SOUTHWESTWARD FOR A
GOOD DISTANCE OFFSHORE. THE 300 MB JET MAX WAS 110-120 KTS PER PLOT
DATA AND WAS LOCATED OVER THE MOHAVE DESERT. SOME SUBTLE DIFFLUENCE
WAS ALSO EVIDENT OVER PORTIONS OF NORTHERN ARIZONA WITH SHOWER
ACTIVITY AS A RESULT. 12Z NAM AND GFS INITIALIZED THIS DIVERGENCE
FAIRLY WELL. SHOWERS HAVE BEEN FILLING IN OVER FAR SOUTHEAST
CALIFORNIA AS DEEPER MOISTURE HAS FINALLY PUSHED OVER THE SOUTHWEST
CALIFORNIA MOUNTAINS. 12Z MODELS LOOK TO BE IN PRETTY GOOD AGREEMENT
ON THE EVOLUTION OF THE MAIN FEATURES AND AS A RESULT WITH THE MAIN
PATTERN OF STORM TOTAL QPF. GREATEST AMOUNT OF QPF WILL BE OVER THE
WESTERN MOGOLLON RIM AND YAVAPAI COUNTY AND PORTIONS OF MOHAVE
COUNTY...WITH NORTHERN PORTIONS OF OUR FORECAST AREA ON THE SOUTHERN
END OF THAT...PLUS A SECONDARY MAXIMUM NEAR AND WEST OF THE LOWER
COLORADO RIVER VALLEY WHICH WAS SEEN IN PREVIOUS RUNS. FOR
SOUTH-CENTRAL ARIZONA...INCLUDING METRO PHOENIX...ANTICIPATE ONLY
ISOLATED LIGHT SHOWERS REST OF TODAY THROUGH THE EVENING BEFORE RAIN
BEGINS IN EARNEST EARLY MONDAY AND TAPERS OFF MONDAY EVENING. MIGHT
EVEN NEED TO TRIM POPS EVEN MORE FOR TODAY. FURTHER WEST...THE MORE
SIGNIFICANT PRECIP STARTS TODAY. GIVEN THE EAST-WEST TIMING
DIFFERENCES...CONTEMPLATING MAKING ADJUSTMENTS TO THE FLOOD WATCH TO
DELAY THE ONSET FOR SOUTH-CENTRAL ARIZONA BY AT LEAST 6 HOURS. ALSO
CONTEMPLATING EXPANSION OF THE WATCH TO THE LOWER COLORADO RIVER
INTO SOUTHEAST CALIFORNIA. MAIN THREAT AREA FOR FLOODING WILL BE
HIGHER TERRAIN AND NEARBY FOOTHILL AREAS. MORE LATER.

&&

.PREVIOUS DISCUSSION ISSUED 243 AM MST/143 AM PST...
EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SLOWLY RETROGRADING AREA
OF LOW PRESSURE OFF THE SOUTHERN CALIFORNIA COAST...WITH QUITE A BIT
OF MID AND HIGH CLOUD COVER DEVELOPING DOWNWIND OF THE COASTAL
MOUNTAINS ALONG THE LOWER COLORADO RIVER VALLEY. FINALLY AFTER MUCH
ANTICIPATION...PRECIP APPEARS TO BE DEVELOPING ACROSS THE WESTERN
PORTIONS OF THE FORECAST AREA AS RADAR RETURNS HAVE INCREASED
SUBSTANTIALLY SINCE 07Z. MOST THE THE PRECIP THAT IS REACHING THE
GROUND IS STILL CONFINED TO THE HIGHER TERRAIN NORTH OF PHOENIX BUT
NONETHELESS IT`S A GOOD SIGN THAT THE ATMOSPHERE IS RESPONDING TO
THE SUBTROPICAL MOISTURE THAT`S BEING ADVECTED INTO THE AREA.

LOW PRESSURE WILL CONTINUE ITS SLOW TREK DOWN THE CALIFORNIA COAST
TODAY...EVENTUALLY STALLING OUT WEST OF SAN DIEGO THIS AFTERNOON. IN
THE MEANTIME IT WILL CONTINUE TAPPING INTO THE ANOMALOUSLY MOIST
SUBTROPICAL PLUME OF MOISTURE THAT IS EVIDENT ON WATER VAPOR IMAGERY
SOUTH OF THE BAJA SPUR. RAIN SHADOWING DOWNWIND OF THE COASTAL
MOUNTAINS WILL PRECLUDE WIDESPREAD PRECIP FROM DEVELOPING THIS
MORNING...BUT EVENTUALLY ENOUGH MOISTURE WILL BUILD UP ACROSS
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA THAT SHOWERS WILL BECOME
MORE WIDESPREAD IN NATURE. THE INHERITED FORECAST ALREADY DEPICTED
THIS SCENARIO AND I ONLY MADE MINOR CHANGES TO THE FORECAST FOR THE
WESTERN FORECAST AREA. TO THE EAST HOWEVER...IT STILL LOOKS LIKE
PRECIP WILL BE SLOW TO DEVELOP AROUND THE PHOENIX AREA...POSSIBLY
HOLDING OFF UNTIL SUNDAY EVENING/EARLY MONDAY MORNING. LATEST NAEFS
GUIDANCE AND THE PAST 2-3 RUNS OF THE SREF INDICATE THE BEST CHANCE
OF PRECIP WILL COME AFTER 00Z TONIGHT AND THUS I TRIMMED POPS A BIT
FOR TODAY. ONLY THINKING WE WILL SEE 20-30 PERCENT CHANCES AROUND
THE METRO...CERTAINLY LOOKING AT HIGHER CHANCES IN THE FOOTHILL
LOCATIONS NORTH/WEST/EAST OF PHOENIX BUT IT LOOKS MORE AND MORE
LIKELY THAT THE MORE WIDESPREAD RAIN WILL BE DELAYED A BIT.

THE QUASI-STATIONARY LOW WEST OF SAN DIEGO WILL GET KICKED THROUGH
THE AREA TOMORROW BY A RAPIDLY APPROACHING SECONDARY TROUGH MOVING
THROUGH NEVADA. THIS WILL BRING MORE WIDESPREAD PRECIP THROUGH THE
ENTIRE FORECAST AREA MONDAY MORNING/MONDAY AFTERNOON...WITH RAPID
CLEARING FROM WEST TO EAST MONDAY NIGHT. WHILE 500MB TEMPERATURE
FORECASTS HAVE RISEN OVER THE PAST FEW DAYS...BUFR SOUNDINGS
INDICATE ENOUGH INSTABILITY POTENTIAL COINCIDENT WITH THE PASSAGE OF
THE TROUGH TO WARRANT AT LEAST A SLIGHT CHANCE OF THUNDER. ONCE THE
TROUGH AXIS MOVES INTO NEW MEXICO MONDAY NIGHT...PRECIP CHANCES /AND
THE POTENTIAL FOR THUNDER/ WILL DROP CONSIDERABLY. AS FOR STORM
TOTAL PRECIP VALUES...ENSEMBLE MEAN IS AROUND 0.75 INCHES ALONG AND
NORTH OF I-10 WITH CLOSER TO 1-1.5 INCHES IN THE OROGRAPHICALLY
FAVORED UPSLOPE AREAS ACROSS NORTHERN LA PAZ COUNTY TO
WICKENBURG...CAVE CREEK...AND THE MOUNTAINS OF SOUTHERN GILA COUNTY.
MADE SOME SLIGHT ADJUSTMENTS TO STORM TOTAL QPF BASED ON THE SLOWER
ARRIVAL OF THE HEAVIER PRECIP BUT STILL ENOUGH TO KEEP THE FLOOD
WATCH INTACT.

THE IMPACTS ASSOCIATED WITH THE SECONDARY TROUGH ON TUESDAY HAVE
BEEN THE SOURCE OF MUCH DEBATE DUE TO VARYING MODEL SOLUTIONS...AND
INDIVIDUAL ENSEMBLE MEMBERS ARE STILL ALL OVER THE MAP THIS MORNING.
NO DOUBT THERE WILL BE SOME LINGERING MOISTURE IN THE AREA...THE
QUESTION IS IF THERE WILL BE ENOUGH FORCING WITH THIS SECONDARY
TROUGH TO TRIGGER SHOWERS ACROSS THE AREA. FELT IT PRUDENT TO KEEP
THE CHANCE OF PRECIP LINGERING ACROSS THE EASTERN HALF OF THE
FORECAST AREA ON TUESDAY ALTHOUGH MOST OF THE SHOWERS SHOULD BE TO
THE NORTH/EAST OF PHOENIX. 00Z DETERMINISTIC MODELS HAVE TRENDED
DRIER ON TUESDAY...WILL NEED TO SEE IF THIS TREND CONTINUES AND IF
THE ENSEMBLES PICK UP ON THIS DRIER SOLUTION.

FROM MID-WEEK ONWARD...RIDGING WILL TAKE HOLD ACROSS THE REGION AND
CONSEQUENTLY TEMPERATURES WILL ALSO CLIMB BACK ABOVE NORMAL BY LATE
WEEK INTO THE WEEKEND.

&&

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

A SLOW APPROACHING COLD FRONT WILL CONTINUE TO DRAW LOW LEVEL
MOISTURE INTO THE AREA FROM NORTHERN BAJA TODAY. ANY SHOWER ACTIVITY
THROUGH THIS AFTERNOON WILL MAINLY STAY TO THE NORTH AND WEST OF THE
PHOENIX TERMINALS...BUT A FEW LIGHT SHOWERS MAY AFFECT KSDL. CIGS
FOR NOW SHOULD STAY ABOVE 8KT FEET THROUGH THE AFTERNOON HOURS...BUT
IF ANY SHOWERS DO OCCUR...CIGS WOULD TEMPORARILY DROP TO AROUND 5-6K
FEET. THE COLD FRONT AND AREA OF RAIN WILL APPROACH THE PHOENIX AREA
SOMETIME LATE THIS EVENING INTO TONIGHT...BUT CONFIDENCE IN THE
EXACT TIME OF ARRIVAL OF THE RAIN...LOWER CIGS...AND ANY RESTRICTED
VISIBILITIES IS STILL SOMEWHAT LOW.

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

MID LEVEL CIGS WILL GRADUALLY LOWER THIS MORNING AND EVENTUALLY DROP
TO MVFR BY AROUND NOON AFTER SOME STEADY RAIN MOVES IN. CONFIDENCE
IS FAIRLY HIGH THAT A BAND OF LIGHT TO MODERATE RAIN WILL AFFECT
SOUTHEAST CALIFORNIA AND PORTIONS OF SOUTHWEST ARIZONA THIS
AFTERNOON INTO THIS EVENING. MAY SEE SOME MVFR VISIBILITIES AT TIMES
DUE TO THE RAIN AND POTENTIALLY IFR CIGS BRIEFLY DEPENDING ON HOW
STEADY THE RAIN ENDS UP BEING. RAIN SHOULD DIMINISH AFTER 09Z
TONIGHT WITH GRADUALLY IMPROVING CIGS BY 12Z MONDAY MORNING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ021>024.

CA...NONE.

&&

$$

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

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







000
FXUS65 KPSR 011143
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
442 AM MST SUN MAR 1 2015

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

&&

...PROLONGED WET WINTER WEATHER EVENT ACROSS THE DESERT SOUTHWEST
SUNDAY THROUGH LATE MONDAY...

&&

.SYNOPSIS...
LOW PRESSURE WILL CONTINUE A SLOW APPROACH OF THE FORECAST
AREA...BRINGING MOISTURE INTO THE REGION ALONG WITH INCREASING
CHANCES OF SHOWERS TODAY AND MONDAY. PERIODS OF HEAVY RAIN ARE
POSSIBLE AT TIMES ESPECIALLY SUNDAY NIGHT THROUGH MONDAY AFTERNOON.
COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS STORM WITH BELOW NORMAL
READINGS EXPECTED MONDAY THROUGH MID WEEK. A RETURN TO ABOVE NORMAL
TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SLOWLY RETROGRADING AREA
OF LOW PRESSURE OFF THE SOUTHERN CALIFORNIA COAST...WITH QUITE A BIT
OF MID AND HIGH CLOUD COVER DEVELOPING DOWNWIND OF THE COASTAL
MOUNTAINS ALONG THE LOWER COLORADO RIVER VALLEY. FINALLY AFTER MUCH
ANTICIPATION...PRECIP APPEARS TO BE DEVELOPING ACROSS THE WESTERN
PORTIONS OF THE FORECAST AREA AS RADAR RETURNS HAVE INCREASED
SUBSTANTIALLY SINCE 07Z. MOST THE THE PRECIP THAT IS REACHING THE
GROUND IS STILL CONFINED TO THE HIGHER TERRAIN NORTH OF PHOENIX BUT
NONETHELESS IT`S A GOOD SIGN THAT THE ATMOSPHERE IS RESPONDING TO
THE SUBTROPICAL MOISTURE THAT`S BEING ADVECTED INTO THE AREA.

LOW PRESSURE WILL CONTINUE ITS SLOW TREK DOWN THE CALIFORNIA COAST
TODAY...EVENTUALLY STALLING OUT WEST OF SAN DIEGO THIS AFTERNOON. IN
THE MEANTIME IT WILL CONTINUE TAPPING INTO THE ANOMALOUSLY MOIST
SUBTROPICAL PLUME OF MOISTURE THAT IS EVIDENT ON WATER VAPOR IMAGERY
SOUTH OF THE BAJA SPUR. RAIN SHADOWING DOWNWIND OF THE COASTAL
MOUNTAINS WILL PRECLUDE WIDESPREAD PRECIP FROM DEVELOPING THIS
MORNING...BUT EVENTUALLY ENOUGH MOISTURE WILL BUILD UP ACROSS
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA THAT SHOWERS WILL BECOME
MORE WIDESPREAD IN NATURE. THE INHERITED FORECAST ALREADY DEPICTED
THIS SCENARIO AND I ONLY MADE MINOR CHANGES TO THE FORECAST FOR THE
WESTERN FORECAST AREA. TO THE EAST HOWEVER...IT STILL LOOKS LIKE
PRECIP WILL BE SLOW TO DEVELOP AROUND THE PHOENIX AREA...POSSIBLY
HOLDING OFF UNTIL SUNDAY EVENING/EARLY MONDAY MORNING. LATEST NAEFS
GUIDANCE AND THE PAST 2-3 RUNS OF THE SREF INDICATE THE BEST CHANCE
OF PRECIP WILL COME AFTER 00Z TONIGHT AND THUS I TRIMMED POPS A BIT
FOR TODAY. ONLY THINKING WE WILL SEE 20-30 PERCENT CHANCES AROUND
THE METRO...CERTAINLY LOOKING AT HIGHER CHANCES IN THE FOOTHILL
LOCATIONS NORTH/WEST/EAST OF PHOENIX BUT IT LOOKS MORE AND MORE
LIKELY THAT THE MORE WIDESPREAD RAIN WILL BE DELAYED A BIT.

THE QUASI-STATIONARY LOW WEST OF SAN DIEGO WILL GET KICKED THROUGH
THE AREA TOMORROW BY A RAPIDLY APPROACHING SECONDARY TROUGH MOVING
THROUGH NEVADA. THIS WILL BRING MORE WIDESPREAD PRECIP THROUGH THE
ENTIRE FORECAST AREA MONDAY MORNING/MONDAY AFTERNOON...WITH RAPID
CLEARING FROM WEST TO EAST MONDAY NIGHT. WHILE 500MB TEMPERATURE
FORECASTS HAVE RISEN OVER THE PAST FEW DAYS...BUFR SOUNDINGS
INDICATE ENOUGH INSTABILITY POTENTIAL COINCIDENT WITH THE PASSAGE OF
THE TROUGH TO WARRANT AT LEAST A SLIGHT CHANCE OF THUNDER. ONCE THE
TROUGH AXIS MOVES INTO NEW MEXICO MONDAY NIGHT...PRECIP CHANCES /AND
THE POTENTIAL FOR THUNDER/ WILL DROP CONSIDERABLY. AS FOR STORM
TOTAL PRECIP VALUES...ENSEMBLE MEAN IS AROUND 0.75 INCHES ALONG AND
NORTH OF I-10 WITH CLOSER TO 1-1.5 INCHES IN THE OROGRAPHICALLY
FAVORED UPSLOPE AREAS ACROSS NORTHERN LA PAZ COUNTY TO
WICKENBURG...CAVE CREEK...AND THE MOUNTAINS OF SOUTHERN GILA COUNTY.
MADE SOME SLIGHT ADJUSTMENTS TO STORM TOTAL QPF BASED ON THE SLOWER
ARRIVAL OF THE HEAVIER PRECIP BUT STILL ENOUGH TO KEEP THE FLOOD
WATCH INTACT.

THE IMPACTS ASSOCIATED WITH THE SECONDARY TROUGH ON TUESDAY HAVE
BEEN THE SOURCE OF MUCH DEBATE DUE TO VARYING MODEL SOLUTIONS...AND
INDIVIDUAL ENSEMBLE MEMBERS ARE STILL ALL OVER THE MAP THIS MORNING.
NO DOUBT THERE WILL BE SOME LINGERING MOISTURE IN THE AREA...THE
QUESTION IS IF THERE WILL BE ENOUGH FORCING WITH THIS SECONDARY
TROUGH TO TRIGGER SHOWERS ACROSS THE AREA. FELT IT PRUDENT TO KEEP
THE CHANCE OF PRECIP LINGERING ACROSS THE EASTERN HALF OF THE
FORECAST AREA ON TUESDAY ALTHOUGH MOST OF THE SHOWERS SHOULD BE TO
THE NORTH/EAST OF PHOENIX. 00Z DETERMINISTIC MODELS HAVE TRENDED
DRIER ON TUESDAY...WILL NEED TO SEE IF THIS TREND CONTINUES AND IF
THE ENSEMBLES PICK UP ON THIS DRIER SOLUTION.

FROM MID-WEEK ONWARD...RIDGING WILL TAKE HOLD ACROSS THE REGION AND
CONSEQUENTLY TEMPERATURES WILL ALSO CLIMB BACK ABOVE NORMAL BY LATE
WEEK INTO THE WEEKEND.

&&

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

A SLOW APPROACHING COLD FRONT WILL CONTINUE TO DRAW LOW LEVEL
MOISTURE INTO THE AREA FROM NORTHERN BAJA TODAY. ANY SHOWER ACTIVITY
THROUGH THIS AFTERNOON WILL MAINLY STAY TO THE NORTH AND WEST OF THE
PHOENIX TERMINALS...BUT A FEW LIGHT SHOWERS MAY AFFECT KSDL. CIGS
FOR NOW SHOULD STAY ABOVE 8KT FEET THROUGH THE AFTERNOON HOURS...BUT
IF ANY SHOWERS DO OCCUR...CIGS WOULD TEMPORARILY DROP TO AROUND 5-6K
FEET. THE COLD FRONT AND AREA OF RAIN WILL APPROACH THE PHOENIX AREA
SOMETIME LATE THIS EVENING INTO TONIGHT...BUT CONFIDENCE IN THE
EXACT TIME OF ARRIVAL OF THE RAIN...LOWER CIGS...AND ANY RESTRICTED
VISIBILITIES IS STILL SOMEWHAT LOW.

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

MID LEVEL CIGS WILL GRADUALLY LOWER THIS MORNING AND EVENTUALLY DROP
TO MVFR BY AROUND NOON AFTER SOME STEADY RAIN MOVES IN. CONFIDENCE
IS FAIRLY HIGH THAT A BAND OF LIGHT TO MODERATE RAIN WILL AFFECT
SOUTHEAST CALIFORNIA AND PORTIONS OF SOUTHWEST ARIZONA THIS
AFTERNOON INTO THIS EVENING. MAY SEE SOME MVFR VISIBILITIES AT TIMES
DUE TO THE RAIN AND POTENTIALLY IFR CIGS BRIEFLY DEPENDING ON HOW
STEADY THE RAIN ENDS UP BEING. RAIN SHOULD DIMINISH AFTER 09Z
TONIGHT WITH GRADUALLY IMPROVING CIGS BY 12Z MONDAY MORNING..

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ021>024.

CA...NONE.

&&

$$

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

DISCUSSION...LEINS
AVIATION...KUHLMAN
FIRE WEATHER...KUHLMAN









000
FXUS65 KPSR 011143 CCA
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
443 AM MST SUN MAR 1 2015

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

&&

...PROLONGED WET WINTER WEATHER EVENT ACROSS THE DESERT SOUTHWEST
SUNDAY THROUGH LATE MONDAY...

&&

.SYNOPSIS...
LOW PRESSURE WILL CONTINUE A SLOW APPROACH OF THE FORECAST
AREA...BRINGING MOISTURE INTO THE REGION ALONG WITH INCREASING
CHANCES OF SHOWERS TODAY AND MONDAY. PERIODS OF HEAVY RAIN ARE
POSSIBLE AT TIMES ESPECIALLY SUNDAY NIGHT THROUGH MONDAY AFTERNOON.
COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS STORM WITH BELOW NORMAL
READINGS EXPECTED MONDAY THROUGH MID WEEK. A RETURN TO ABOVE NORMAL
TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SLOWLY RETROGRADING AREA
OF LOW PRESSURE OFF THE SOUTHERN CALIFORNIA COAST...WITH QUITE A BIT
OF MID AND HIGH CLOUD COVER DEVELOPING DOWNWIND OF THE COASTAL
MOUNTAINS ALONG THE LOWER COLORADO RIVER VALLEY. FINALLY AFTER MUCH
ANTICIPATION...PRECIP APPEARS TO BE DEVELOPING ACROSS THE WESTERN
PORTIONS OF THE FORECAST AREA AS RADAR RETURNS HAVE INCREASED
SUBSTANTIALLY SINCE 07Z. MOST THE THE PRECIP THAT IS REACHING THE
GROUND IS STILL CONFINED TO THE HIGHER TERRAIN NORTH OF PHOENIX BUT
NONETHELESS IT`S A GOOD SIGN THAT THE ATMOSPHERE IS RESPONDING TO
THE SUBTROPICAL MOISTURE THAT`S BEING ADVECTED INTO THE AREA.

LOW PRESSURE WILL CONTINUE ITS SLOW TREK DOWN THE CALIFORNIA COAST
TODAY...EVENTUALLY STALLING OUT WEST OF SAN DIEGO THIS AFTERNOON. IN
THE MEANTIME IT WILL CONTINUE TAPPING INTO THE ANOMALOUSLY MOIST
SUBTROPICAL PLUME OF MOISTURE THAT IS EVIDENT ON WATER VAPOR IMAGERY
SOUTH OF THE BAJA SPUR. RAIN SHADOWING DOWNWIND OF THE COASTAL
MOUNTAINS WILL PRECLUDE WIDESPREAD PRECIP FROM DEVELOPING THIS
MORNING...BUT EVENTUALLY ENOUGH MOISTURE WILL BUILD UP ACROSS
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA THAT SHOWERS WILL BECOME
MORE WIDESPREAD IN NATURE. THE INHERITED FORECAST ALREADY DEPICTED
THIS SCENARIO AND I ONLY MADE MINOR CHANGES TO THE FORECAST FOR THE
WESTERN FORECAST AREA. TO THE EAST HOWEVER...IT STILL LOOKS LIKE
PRECIP WILL BE SLOW TO DEVELOP AROUND THE PHOENIX AREA...POSSIBLY
HOLDING OFF UNTIL SUNDAY EVENING/EARLY MONDAY MORNING. LATEST NAEFS
GUIDANCE AND THE PAST 2-3 RUNS OF THE SREF INDICATE THE BEST CHANCE
OF PRECIP WILL COME AFTER 00Z TONIGHT AND THUS I TRIMMED POPS A BIT
FOR TODAY. ONLY THINKING WE WILL SEE 20-30 PERCENT CHANCES AROUND
THE METRO...CERTAINLY LOOKING AT HIGHER CHANCES IN THE FOOTHILL
LOCATIONS NORTH/WEST/EAST OF PHOENIX BUT IT LOOKS MORE AND MORE
LIKELY THAT THE MORE WIDESPREAD RAIN WILL BE DELAYED A BIT.

THE QUASI-STATIONARY LOW WEST OF SAN DIEGO WILL GET KICKED THROUGH
THE AREA TOMORROW BY A RAPIDLY APPROACHING SECONDARY TROUGH MOVING
THROUGH NEVADA. THIS WILL BRING MORE WIDESPREAD PRECIP THROUGH THE
ENTIRE FORECAST AREA MONDAY MORNING/MONDAY AFTERNOON...WITH RAPID
CLEARING FROM WEST TO EAST MONDAY NIGHT. WHILE 500MB TEMPERATURE
FORECASTS HAVE RISEN OVER THE PAST FEW DAYS...BUFR SOUNDINGS
INDICATE ENOUGH INSTABILITY POTENTIAL COINCIDENT WITH THE PASSAGE OF
THE TROUGH TO WARRANT AT LEAST A SLIGHT CHANCE OF THUNDER. ONCE THE
TROUGH AXIS MOVES INTO NEW MEXICO MONDAY NIGHT...PRECIP CHANCES /AND
THE POTENTIAL FOR THUNDER/ WILL DROP CONSIDERABLY. AS FOR STORM
TOTAL PRECIP VALUES...ENSEMBLE MEAN IS AROUND 0.75 INCHES ALONG AND
NORTH OF I-10 WITH CLOSER TO 1-1.5 INCHES IN THE OROGRAPHICALLY
FAVORED UPSLOPE AREAS ACROSS NORTHERN LA PAZ COUNTY TO
WICKENBURG...CAVE CREEK...AND THE MOUNTAINS OF SOUTHERN GILA COUNTY.
MADE SOME SLIGHT ADJUSTMENTS TO STORM TOTAL QPF BASED ON THE SLOWER
ARRIVAL OF THE HEAVIER PRECIP BUT STILL ENOUGH TO KEEP THE FLOOD
WATCH INTACT.

THE IMPACTS ASSOCIATED WITH THE SECONDARY TROUGH ON TUESDAY HAVE
BEEN THE SOURCE OF MUCH DEBATE DUE TO VARYING MODEL SOLUTIONS...AND
INDIVIDUAL ENSEMBLE MEMBERS ARE STILL ALL OVER THE MAP THIS MORNING.
NO DOUBT THERE WILL BE SOME LINGERING MOISTURE IN THE AREA...THE
QUESTION IS IF THERE WILL BE ENOUGH FORCING WITH THIS SECONDARY
TROUGH TO TRIGGER SHOWERS ACROSS THE AREA. FELT IT PRUDENT TO KEEP
THE CHANCE OF PRECIP LINGERING ACROSS THE EASTERN HALF OF THE
FORECAST AREA ON TUESDAY ALTHOUGH MOST OF THE SHOWERS SHOULD BE TO
THE NORTH/EAST OF PHOENIX. 00Z DETERMINISTIC MODELS HAVE TRENDED
DRIER ON TUESDAY...WILL NEED TO SEE IF THIS TREND CONTINUES AND IF
THE ENSEMBLES PICK UP ON THIS DRIER SOLUTION.

FROM MID-WEEK ONWARD...RIDGING WILL TAKE HOLD ACROSS THE REGION AND
CONSEQUENTLY TEMPERATURES WILL ALSO CLIMB BACK ABOVE NORMAL BY LATE
WEEK INTO THE WEEKEND.

&&

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

A SLOW APPROACHING COLD FRONT WILL CONTINUE TO DRAW LOW LEVEL
MOISTURE INTO THE AREA FROM NORTHERN BAJA TODAY. ANY SHOWER ACTIVITY
THROUGH THIS AFTERNOON WILL MAINLY STAY TO THE NORTH AND WEST OF THE
PHOENIX TERMINALS...BUT A FEW LIGHT SHOWERS MAY AFFECT KSDL. CIGS
FOR NOW SHOULD STAY ABOVE 8KT FEET THROUGH THE AFTERNOON HOURS...BUT
IF ANY SHOWERS DO OCCUR...CIGS WOULD TEMPORARILY DROP TO AROUND 5-6K
FEET. THE COLD FRONT AND AREA OF RAIN WILL APPROACH THE PHOENIX AREA
SOMETIME LATE THIS EVENING INTO TONIGHT...BUT CONFIDENCE IN THE
EXACT TIME OF ARRIVAL OF THE RAIN...LOWER CIGS...AND ANY RESTRICTED
VISIBILITIES IS STILL SOMEWHAT LOW.

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

MID LEVEL CIGS WILL GRADUALLY LOWER THIS MORNING AND EVENTUALLY DROP
TO MVFR BY AROUND NOON AFTER SOME STEADY RAIN MOVES IN. CONFIDENCE
IS FAIRLY HIGH THAT A BAND OF LIGHT TO MODERATE RAIN WILL AFFECT
SOUTHEAST CALIFORNIA AND PORTIONS OF SOUTHWEST ARIZONA THIS
AFTERNOON INTO THIS EVENING. MAY SEE SOME MVFR VISIBILITIES AT TIMES
DUE TO THE RAIN AND POTENTIALLY IFR CIGS BRIEFLY DEPENDING ON HOW
STEADY THE RAIN ENDS UP BEING. RAIN SHOULD DIMINISH AFTER 09Z
TONIGHT WITH GRADUALLY IMPROVING CIGS BY 12Z MONDAY MORNING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ021>024.

CA...NONE.

&&

$$

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

DISCUSSION...LEINS
AVIATION...KUHLMAN
FIRE WEATHER...KUHLMAN










000
FXUS65 KPSR 011143 CCA
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
443 AM MST SUN MAR 1 2015

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

&&

...PROLONGED WET WINTER WEATHER EVENT ACROSS THE DESERT SOUTHWEST
SUNDAY THROUGH LATE MONDAY...

&&

.SYNOPSIS...
LOW PRESSURE WILL CONTINUE A SLOW APPROACH OF THE FORECAST
AREA...BRINGING MOISTURE INTO THE REGION ALONG WITH INCREASING
CHANCES OF SHOWERS TODAY AND MONDAY. PERIODS OF HEAVY RAIN ARE
POSSIBLE AT TIMES ESPECIALLY SUNDAY NIGHT THROUGH MONDAY AFTERNOON.
COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS STORM WITH BELOW NORMAL
READINGS EXPECTED MONDAY THROUGH MID WEEK. A RETURN TO ABOVE NORMAL
TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SLOWLY RETROGRADING AREA
OF LOW PRESSURE OFF THE SOUTHERN CALIFORNIA COAST...WITH QUITE A BIT
OF MID AND HIGH CLOUD COVER DEVELOPING DOWNWIND OF THE COASTAL
MOUNTAINS ALONG THE LOWER COLORADO RIVER VALLEY. FINALLY AFTER MUCH
ANTICIPATION...PRECIP APPEARS TO BE DEVELOPING ACROSS THE WESTERN
PORTIONS OF THE FORECAST AREA AS RADAR RETURNS HAVE INCREASED
SUBSTANTIALLY SINCE 07Z. MOST THE THE PRECIP THAT IS REACHING THE
GROUND IS STILL CONFINED TO THE HIGHER TERRAIN NORTH OF PHOENIX BUT
NONETHELESS IT`S A GOOD SIGN THAT THE ATMOSPHERE IS RESPONDING TO
THE SUBTROPICAL MOISTURE THAT`S BEING ADVECTED INTO THE AREA.

LOW PRESSURE WILL CONTINUE ITS SLOW TREK DOWN THE CALIFORNIA COAST
TODAY...EVENTUALLY STALLING OUT WEST OF SAN DIEGO THIS AFTERNOON. IN
THE MEANTIME IT WILL CONTINUE TAPPING INTO THE ANOMALOUSLY MOIST
SUBTROPICAL PLUME OF MOISTURE THAT IS EVIDENT ON WATER VAPOR IMAGERY
SOUTH OF THE BAJA SPUR. RAIN SHADOWING DOWNWIND OF THE COASTAL
MOUNTAINS WILL PRECLUDE WIDESPREAD PRECIP FROM DEVELOPING THIS
MORNING...BUT EVENTUALLY ENOUGH MOISTURE WILL BUILD UP ACROSS
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA THAT SHOWERS WILL BECOME
MORE WIDESPREAD IN NATURE. THE INHERITED FORECAST ALREADY DEPICTED
THIS SCENARIO AND I ONLY MADE MINOR CHANGES TO THE FORECAST FOR THE
WESTERN FORECAST AREA. TO THE EAST HOWEVER...IT STILL LOOKS LIKE
PRECIP WILL BE SLOW TO DEVELOP AROUND THE PHOENIX AREA...POSSIBLY
HOLDING OFF UNTIL SUNDAY EVENING/EARLY MONDAY MORNING. LATEST NAEFS
GUIDANCE AND THE PAST 2-3 RUNS OF THE SREF INDICATE THE BEST CHANCE
OF PRECIP WILL COME AFTER 00Z TONIGHT AND THUS I TRIMMED POPS A BIT
FOR TODAY. ONLY THINKING WE WILL SEE 20-30 PERCENT CHANCES AROUND
THE METRO...CERTAINLY LOOKING AT HIGHER CHANCES IN THE FOOTHILL
LOCATIONS NORTH/WEST/EAST OF PHOENIX BUT IT LOOKS MORE AND MORE
LIKELY THAT THE MORE WIDESPREAD RAIN WILL BE DELAYED A BIT.

THE QUASI-STATIONARY LOW WEST OF SAN DIEGO WILL GET KICKED THROUGH
THE AREA TOMORROW BY A RAPIDLY APPROACHING SECONDARY TROUGH MOVING
THROUGH NEVADA. THIS WILL BRING MORE WIDESPREAD PRECIP THROUGH THE
ENTIRE FORECAST AREA MONDAY MORNING/MONDAY AFTERNOON...WITH RAPID
CLEARING FROM WEST TO EAST MONDAY NIGHT. WHILE 500MB TEMPERATURE
FORECASTS HAVE RISEN OVER THE PAST FEW DAYS...BUFR SOUNDINGS
INDICATE ENOUGH INSTABILITY POTENTIAL COINCIDENT WITH THE PASSAGE OF
THE TROUGH TO WARRANT AT LEAST A SLIGHT CHANCE OF THUNDER. ONCE THE
TROUGH AXIS MOVES INTO NEW MEXICO MONDAY NIGHT...PRECIP CHANCES /AND
THE POTENTIAL FOR THUNDER/ WILL DROP CONSIDERABLY. AS FOR STORM
TOTAL PRECIP VALUES...ENSEMBLE MEAN IS AROUND 0.75 INCHES ALONG AND
NORTH OF I-10 WITH CLOSER TO 1-1.5 INCHES IN THE OROGRAPHICALLY
FAVORED UPSLOPE AREAS ACROSS NORTHERN LA PAZ COUNTY TO
WICKENBURG...CAVE CREEK...AND THE MOUNTAINS OF SOUTHERN GILA COUNTY.
MADE SOME SLIGHT ADJUSTMENTS TO STORM TOTAL QPF BASED ON THE SLOWER
ARRIVAL OF THE HEAVIER PRECIP BUT STILL ENOUGH TO KEEP THE FLOOD
WATCH INTACT.

THE IMPACTS ASSOCIATED WITH THE SECONDARY TROUGH ON TUESDAY HAVE
BEEN THE SOURCE OF MUCH DEBATE DUE TO VARYING MODEL SOLUTIONS...AND
INDIVIDUAL ENSEMBLE MEMBERS ARE STILL ALL OVER THE MAP THIS MORNING.
NO DOUBT THERE WILL BE SOME LINGERING MOISTURE IN THE AREA...THE
QUESTION IS IF THERE WILL BE ENOUGH FORCING WITH THIS SECONDARY
TROUGH TO TRIGGER SHOWERS ACROSS THE AREA. FELT IT PRUDENT TO KEEP
THE CHANCE OF PRECIP LINGERING ACROSS THE EASTERN HALF OF THE
FORECAST AREA ON TUESDAY ALTHOUGH MOST OF THE SHOWERS SHOULD BE TO
THE NORTH/EAST OF PHOENIX. 00Z DETERMINISTIC MODELS HAVE TRENDED
DRIER ON TUESDAY...WILL NEED TO SEE IF THIS TREND CONTINUES AND IF
THE ENSEMBLES PICK UP ON THIS DRIER SOLUTION.

FROM MID-WEEK ONWARD...RIDGING WILL TAKE HOLD ACROSS THE REGION AND
CONSEQUENTLY TEMPERATURES WILL ALSO CLIMB BACK ABOVE NORMAL BY LATE
WEEK INTO THE WEEKEND.

&&

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

A SLOW APPROACHING COLD FRONT WILL CONTINUE TO DRAW LOW LEVEL
MOISTURE INTO THE AREA FROM NORTHERN BAJA TODAY. ANY SHOWER ACTIVITY
THROUGH THIS AFTERNOON WILL MAINLY STAY TO THE NORTH AND WEST OF THE
PHOENIX TERMINALS...BUT A FEW LIGHT SHOWERS MAY AFFECT KSDL. CIGS
FOR NOW SHOULD STAY ABOVE 8KT FEET THROUGH THE AFTERNOON HOURS...BUT
IF ANY SHOWERS DO OCCUR...CIGS WOULD TEMPORARILY DROP TO AROUND 5-6K
FEET. THE COLD FRONT AND AREA OF RAIN WILL APPROACH THE PHOENIX AREA
SOMETIME LATE THIS EVENING INTO TONIGHT...BUT CONFIDENCE IN THE
EXACT TIME OF ARRIVAL OF THE RAIN...LOWER CIGS...AND ANY RESTRICTED
VISIBILITIES IS STILL SOMEWHAT LOW.

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

MID LEVEL CIGS WILL GRADUALLY LOWER THIS MORNING AND EVENTUALLY DROP
TO MVFR BY AROUND NOON AFTER SOME STEADY RAIN MOVES IN. CONFIDENCE
IS FAIRLY HIGH THAT A BAND OF LIGHT TO MODERATE RAIN WILL AFFECT
SOUTHEAST CALIFORNIA AND PORTIONS OF SOUTHWEST ARIZONA THIS
AFTERNOON INTO THIS EVENING. MAY SEE SOME MVFR VISIBILITIES AT TIMES
DUE TO THE RAIN AND POTENTIALLY IFR CIGS BRIEFLY DEPENDING ON HOW
STEADY THE RAIN ENDS UP BEING. RAIN SHOULD DIMINISH AFTER 09Z
TONIGHT WITH GRADUALLY IMPROVING CIGS BY 12Z MONDAY MORNING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
COOL AND STILL RELATIVELY MOIST CONDITIONS WILL BE PRESENT ON
TUESDAY WITH LINGERING RAIN CHANCES ACROSS SOUTH-CENTRAL ARIZONA.
WEAK HIGH PRESSURE AND DRYING CONDITIONS WILL MOVE IN STARTING
WEDNESDAY. TEMPERATURES WILL WARM BACK TOWARD NORMALS BY THURSDAY
AND THEN A FEW DEGREES ABOVE NORMAL FOR FRIDAY AND SATURDAY. WINDS
WILL BE RELATIVELY LIGHT THROUGH THE PERIOD...BUT AFTERNOON
BREEZINESS IS EXPECTED ON WEDNESDAY THROUGH FRIDAY. MINIMUM
HUMIDITIES WILL DROP INTO THE 20S ON WEDNESDAY AND THEN INTO THE
TEENS EACH AFTERNOON STARTING THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ021>024.

CA...NONE.

&&

$$

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

DISCUSSION...LEINS
AVIATION...KUHLMAN
FIRE WEATHER...KUHLMAN











000
FXUS65 KPSR 010943
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
243 AM MST SUN MAR 1 2015

...PROLONGED WET WINTER WEATHER EVENT ACROSS THE DESERT SOUTHWEST
SUNDAY THROUGH LATE MONDAY...

&&

.SYNOPSIS...
LOW PRESSURE WILL CONTINUE A SLOW APPROACH OF THE FORECAST
AREA...BRINGING MOISTURE INTO THE REGION ALONG WITH INCREASING
CHANCES OF SHOWERS TODAY AND MONDAY. PERIODS OF HEAVY RAIN ARE
POSSIBLE AT TIMES ESPECIALLY SUNDAY NIGHT THROUGH MONDAY AFTERNOON.
COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS STORM WITH BELOW NORMAL
READINGS EXPECTED MONDAY THROUGH MID WEEK. A RETURN TO ABOVE NORMAL
TEMPERATURES IS LIKELY BY LATE WEEK.

&&

.DISCUSSION...
EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SLOWLY RETROGRADING AREA
OF LOW PRESSURE OFF THE SOUTHERN CALIFORNIA COAST...WITH QUITE A BIT
OF MID AND HIGH CLOUD COVER DEVELOPING DOWNWIND OF THE COASTAL
MOUNTAINS ALONG THE LOWER COLORADO RIVER VALLEY. FINALLY AFTER MUCH
ANTICIPATION...PRECIP APPEARS TO BE DEVELOPING ACROSS THE WESTERN
PORTIONS OF THE FORECAST AREA AS RADAR RETURNS HAVE INCREASED
SUBSTANTIALLY SINCE 07Z. MOST THE THE PRECIP THAT IS REACHING THE
GROUND IS STILL CONFINED TO THE HIGHER TERRAIN NORTH OF PHOENIX BUT
NONETHELESS IT`S A GOOD SIGN THAT THE ATMOSPHERE IS RESPONDING TO
THE SUBTROPICAL MOISTURE THAT`S BEING ADVECTED INTO THE AREA.

LOW PRESSURE WILL CONTINUE ITS SLOW TREK DOWN THE CALIFORNIA COAST
TODAY...EVENTUALLY STALLING OUT WEST OF SAN DIEGO THIS AFTERNOON. IN
THE MEANTIME IT WILL CONTINUE TAPPING INTO THE ANOMALOUSLY MOIST
SUBTROPICAL PLUME OF MOISTURE THAT IS EVIDENT ON WATER VAPOR IMAGERY
SOUTH OF THE BAJA SPUR. RAIN SHADOWING DOWNWIND OF THE COASTAL
MOUNTAINS WILL PRECLUDE WIDESPREAD PRECIP FROM DEVELOPING THIS
MORNING...BUT EVENTUALLY ENOUGH MOISTURE WILL BUILD UP ACROSS
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA THAT SHOWERS WILL BECOME
MORE WIDESPREAD IN NATURE. THE INHERITED FORECAST ALREADY DEPICTED
THIS SCENARIO AND I ONLY MADE MINOR CHANGES TO THE FORECAST FOR THE
WESTERN FORECAST AREA. TO THE EAST HOWEVER...IT STILL LOOKS LIKE
PRECIP WILL BE SLOW TO DEVELOP AROUND THE PHOENIX AREA...POSSIBLY
HOLDING OFF UNTIL SUNDAY EVENING/EARLY MONDAY MORNING. LATEST NAEFS
GUIDANCE AND THE PAST 2-3 RUNS OF THE SREF INDICATE THE BEST CHANCE
OF PRECIP WILL COME AFTER 00Z TONIGHT AND THUS I TRIMMED POPS A BIT
FOR TODAY. ONLY THINKING WE WILL SEE 20-30 PERCENT CHANCES AROUND
THE METRO...CERTAINLY LOOKING AT HIGHER CHANCES IN THE FOOTHILL
LOCATIONS NORTH/WEST/EAST OF PHOENIX BUT IT LOOKS MORE AND MORE
LIKELY THAT THE MORE WIDESPREAD RAIN WILL BE DELAYED A BIT.

THE QUASI-STATIONARY LOW WEST OF SAN DIEGO WILL GET KICKED THROUGH
THE AREA TOMORROW BY A RAPIDLY APPROACHING SECONDARY TROUGH MOVING
THROUGH NEVADA. THIS WILL BRING MORE WIDESPREAD PRECIP THROUGH THE
ENTIRE FORECAST AREA MONDAY MORNING/MONDAY AFTERNOON...WITH RAPID
CLEARING FROM WEST TO EAST MONDAY NIGHT. WHILE 500MB TEMPERATURE
FORECASTS HAVE RISEN OVER THE PAST FEW DAYS...BUFR SOUNDINGS
INDICATE ENOUGH INSTABILITY POTENTIAL COINCIDENT WITH THE PASSAGE OF
THE TROUGH TO WARRANT AT LEAST A SLIGHT CHANCE OF THUNDER. ONCE THE
TROUGH AXIS MOVES INTO NEW MEXICO MONDAY NIGHT...PRECIP CHANCES /AND
THE POTENTIAL FOR THUNDER/ WILL DROP CONSIDERABLY. AS FOR STORM
TOTAL PRECIP VALUES...ENSEMBLE MEAN IS AROUND 0.75 INCHES ALONG AND
NORTH OF I-10 WITH CLOSER TO 1-1.5 INCHES IN THE OROGRAPHICALLY
FAVORED UPSLOPE AREAS ACROSS NORTHERN LA PAZ COUNTY TO
WICKENBURG...CAVE CREEK...AND THE MOUNTAINS OF SOUTHERN GILA COUNTY.
MADE SOME SLIGHT ADJUSTMENTS TO STORM TOTAL QPF BASED ON THE SLOWER
ARRIVAL OF THE HEAVIER PRECIP BUT STILL ENOUGH TO KEEP THE FLOOD
WATCH INTACT.

THE IMPACTS ASSOCIATED WITH THE SECONDARY TROUGH ON TUESDAY HAVE
BEEN THE SOURCE OF MUCH DEBATE DUE TO VARYING MODEL SOLUTIONS...AND
INDIVIDUAL ENSEMBLE MEMBERS ARE STILL ALL OVER THE MAP THIS MORNING.
NO DOUBT THERE WILL BE SOME LINGERING MOISTURE IN THE AREA...THE
QUESTION IS IF THERE WILL BE ENOUGH FORCING WITH THIS SECONDARY
TROUGH TO TRIGGER SHOWERS ACROSS THE AREA. FELT IT PRUDENT TO KEEP
THE CHANCE OF PRECIP LINGERING ACROSS THE EASTERN HALF OF THE
FORECAST AREA ON TUESDAY ALTHOUGH MOST OF THE SHOWERS SHOULD BE TO
THE NORTH/EAST OF PHOENIX. 00Z DETERMINISTIC MODELS HAVE TRENDED
DRIER ON TUESDAY...WILL NEED TO SEE IF THIS TREND CONTINUES AND IF
THE ENSEMBLES PICK UP ON THIS DRIER SOLUTION.

FROM MID-WEEK ONWARD...RIDGING WILL TAKE HOLD ACROSS THE REGION AND
CONSEQUENTLY TEMPERATURES WILL ALSO CLIMB BACK ABOVE NORMAL BY LATE
WEEK INTO THE WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
A SLOW APPROACHING COLD FRONT WILL CONTINUE DRAW LOW LEVEL MOISTURE
INTO THE AREA FROM NORTHERN BAJA THROUGH SUNDAY AFTERNOON. ISOLATED
SHOWERS IN THE PHOENIX VALLEY ARE EXPECTED...WITH A BRIEF HEAVIER
PERIOD AROUND SUNRISE SUNDAY. THEREFORE SCT CLDS BASED NEAR 4 THSD
AGL WITH BKN-OVC CLDS BETWEEN 5-6 THSD AGL WILL CONTINUE THROUGH AT
LEAST 20Z SUN. LIGHT SOUTH WIND IS EXPECTED THROUGH 14Z...INCREASING
TO 10 TO 15 KNOTS FROM 14Z-20Z SUN.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
THROUGH 16Z SUN...SCT CLDS NEAR 6 THSD AGL..BKN CLDS 10-12 THSD AGL.
WEST TO SOUTHWEST WIND 5 TO 10 KNOTS. FROM 16Z SUN TO 20Z SUN...
CLDS LOWERING TO BKN 6 THSD AGL WITH SCT RAIN SHOWERS. LIGHT SOUTH
WIND 5 TO 10 KNOTS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
COOL AND WET CONDITIONS WILL BE PRESENT ON MONDAY AND LIKELY INTO
TUESDAY WITH THE BEST CHANCES FOR WIDESPREAD RAINS ON MONDAY. THERE
WILL BE A CHANCE OF A FEW THUNDERSTORMS ON MONDAY. HUMIDITIES WILL
BE WELL ABOVE TYPICAL VALUES THROUGH TUESDAY BEFORE MINIMUM VALUES
FALL BACK INTO THE TEENS STARTING THURSDAY AFTERNOON. PERIODS OF
BREEZY SOUTHWESTERLY WINDS CAN BE EXPECTED ON MONDAY AND AGAIN ON
WEDNESDAY. HIGH TEMPERATURES ACROSS THE DESERTS WILL ONLY REACH INTO
THE 60S THROUGH WEDNESDAY. HIGH PRESSURE BRINGING WARMER AND DRIER
WEATHER SHOULD MOVE IN STARTING LATER WEDNESDAY AND SHOULD PERSIST
THROUGH THE END OF THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM 5 PM TODAY THROUGH 5 PM MONDAY AZZ021>024.

CA...NONE.

&&

$$

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

DISCUSSION...LEINS
AVIATION...VASQUEZ
FIRE WEATHER...KUHLMAN







000
FXUS65 KPSR 010323
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
820 PM MST SAT FEB 28 2015

...PROLONGED WET WINTER WEATHER EVENT ACROSS THE DESERT SOUTHWEST
SUNDAY THROUGH LATE MONDAY...

&&

.SYNOPSIS...
LOW PRESSURE WILL CONTINUE A SLOW APPROACH OF THE FORECAST
AREA...BRINGING MOISTURE INTO THE REGION ALONG WITH INCREASING
CHANCES OF SHOWERS SUNDAY AND MONDAY. PERIODS OF HEAVY RAIN ARE
POSSIBLE AT TIMES ESPECIALLY SUNDAY NIGHT THROUGH MONDAY AFTERNOON.
COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS STORM WITH BELOW NORMAL
READINGS EXPECTED MONDAY THROUGH LATE WEEK.

&&

.DISCUSSION...
THE STORM TRACK HAS SHIFTED SOUTH FROM SOUTHERN CA TO CENTRAL AZ.
ONE DISTURBANCE MOVED THROUGH CENTRAL AND NORTHERN AZ SATURDAY WITH
A SECOND AND MORE POWERFUL ONE DEVELOPING AND INTENSIFYING OFF THE
CENTRAL CA COAST THIS EVENING. THIS DISTURBANCE WILL MOVE THROUGH AZ
MONDAY...HOWEVER IN THE INTERIM TONIGHT THROUGH SUNDAY NIGHT...THE
COLD FRONT WILL REMAIN NEARLY STATIONARY ACROSS CENTRAL AZ.

REGIONAL WEATHER BALLOON SOUNDINGS SAT MORNING AND EVENING SHOWED
LOW LEVEL MOISTURE ALONG THE FRONTAL ZONE HAD BEEN SLOWLY INCREASING
WITH TIME.  AT 5 PM MST A RELATIVELY HIGH LOW LEVEL MOISTURE PLUME
EXTENDED FROM NORTHERN BAJA INTO SOUTHERN AZ. AS THE DISTURBANCE
OFFSHORE DEVELOPS SOUTHWARD TONIGHT AND SUNDAY...ADDITIONAL MOISTURE
WILL SPIN UP INTO THE SYSTEM FOR A SIGNIFICANT RAIN EVENT LATE
SUNDAY NIGHT AND MONDAY. AS THE MOISTURE INCREASES ALONG THE FRONTAL
ZONE TONIGHT AND SUNDAY...SCT LIGHT SHOWERS ARE EXPECTED...WITH
MAYBE SLIGHTLY HEAVIER AMOUNTS FOR A 6 HOUR PERIOD SUNDAY MORNING.
UPDATES WERE TO INCREASE PRECIP PROBABILITIES IN SOUTH CENTRAL AZ
TONIGHT AND SUNDAY...INCLUDING THE PHOENIX AREA.

OTHERWISE AS NOTE ABOVE...A SIGNIFICANT AMOUNT OF MOISTURE IS
FORECAST TO SURGE INTO SOUTHWEST AND SOUTH CENTRAL AZ LATE SUNDAY
NIGHT AND MONDAY AS THE PACIFIC DISTURBANCE APPROACHES. LOW LEVEL
SOUTHWEST WINDS SHOULD BE FAIRLY STRONG MONDAY...IN THE 20 TO 35
KNOT RANGE...ENHANCING THE POTENTIAL FOR UPSLOPE PRECIP IN LA
PAZ...NORTHERN MARICOPA...AND SOUTHERN GILA COUNTIES. THE FLOOD
WATCH FOR THESE AREAS STARTING SUNDAY AFTERNOON THROUGH MONDAY
AFTERNOON LOOKS OK FOR NOW.

OTHERWISE...FORECASTS LOOK GOOD SHOWING A PROLONGED CHANCE OF PRECIP
TONIGHT THROUGH MONDAY...CULMINATING IN THE HEAVIEST PRECIP LATE
SUNDAY NIGHT AND MONDAY ACROSS SOUTHWEST AND SOUTH CENTRAL AZ.
PREVIOUS DISCUSSION BELOW STILL APPLIES.



.PREVIOUS DISCUSSION...342 PM MST...
AFTERNOON IR/WV IMAGERY LOOPS SHOW THE UPPER LOW CONTINUING TO
TRAVEL SOUTHWARD THROUGH CA...WITH THE CIRCULATION CENTER NOW SOUTH
OF THE SAN FRANCISCO BAY AREA. DOWNSTREAM FROM THE MAIN UPPER
LOW...UNSETTLED WESTERLY MID AND UPPER JET FLOW SPANS FROM THE CA
COAST AND ACROSS MUCH OF THE SOUTHERN CONUS. SPOTTY LIGHT RAIN
SHOWER COVERAGE CONTINUES ACROSS THE NORTHERN FRINGE OF MARICOPA
COUNTY THIS AFTERNOON. ADDITIONAL AREA OF LIGHT RAIN SHOWERS HAVE
BEGUN TO PERCOLATE WELL EAST OF THE PHOENIX METRO...ALONG THE US60
CORRIDOR. IN ADDITION...STRONG SURFACE WINDS CONTINUE ACROSS MUCH OF
THE REGION...ESPECIALLY THE SOUTHEAST CA FORECAST ZONES...WITH MANY
SITES REPORTING GUSTS INTO THE 30 KT/MID 30 MPH RANGE. STRONG WINDS
WILL EVENTUALLY TAPER BACK IN SPEEDS LATER INTO THE EVENING WHILE
STILL REMAINING SLIGHTLY ELEVATED OVER AREA RIDGETOPS. SPOTTY SHOWER
COVERAGE WILL ALSO CONTINUE...ESPECIALLY FOR THE FOOTHILL/HIGH
TERRAIN LOCALES NORTH/EAST OF PHOENIX WITH ADDITIONAL ACCUMULATIONS
ON THE ORDER OF A COUPLE HUNDREDTHS TO POSSIBLE 0.10" OR SO. POP
FORECASTS FOR THE REST OF THE AFTERNOON KEEP ISOLATED SHOWER MENTION
OVER PORTIONS OF THE SOUTH-CENTRAL AZ DESERTS...WITH INCREASING
PERCENTAGES AND COVERAGE BECOMING SCATTERED THE FURTHER
NORTH/NORTHEAST OF PHOENIX YOU GO.

IN GENERAL...VERY LITTLE HAS CHANGED WITH THE OVERALL NARRATIVE OF
SENSIBLE WEATHER IMPACTS ASSOCIATED WITH THIS SYSTEM FOR SUNDAY AND
THE EARLY WORK WEEK. HOWEVER...FORECAST SOLNS HAVE ONCE AGAIN
SHIFTED THE SIGNIFICANT IMPACT WINDOWS OUT BY ANOTHER 6-HRS OR SO.
THE TRANSLATES TO THE WINDOWS WITH MODERATE TO HEAVY RAINFALL
CONCERNS OVER SOUTHEAST CA LATER INTO THE DAY SUNDAY...MORE LIKELY
AFTER 18Z. IN ADDITION...THE WINDOW FOR MODERATE TO HEAVY RAINFALL
OVER THE SOUTH-CENTRAL AZ DESERTS/FOOTHILLS HAS SHIFTED PRIMARILY TO
MONDAY. ONLY SLIGHT ADJUSTMENTS WERE WORKED INTO THE QPF
GRIDS...WITH UPWARD NUDGES OF STORM TOTAL VALUES PUSHING 2 INCHES
POSSIBLY OVER THE FAR NORTHEAST MARICOPA COUNTY CORNER AND 1.5 INCH
VALUES FOR WICKENBURG AND NORTHWEST MARICOPA COUNTY. AROUND 1 INCH
STORM TOTAL HOLDS ACROSS THE PHOENIX METRO WITH 0.60 TO 0.90 OR SO
READINGS POSSIBLE OUT ALONG THE LOWER CO RIVER VALLEY AND SOUTHEAST
CA.

THE UPPER LOW WILL CONTINUE TO DIG DOWN TO THE SOCAL COAST THROUGH
THE EVENING...STALLING OUT WEST OF SAN DIEGO/LA FOR MUCH OF THE DAY
SUNDAY. MEANWHILE...DECENT BAND OF ELEVATED SUBTROPIC MOISTURE WILL
BE DRAWN NORTHWARD TOWARDS THE UPPER LOW AND OVER THE BAJA
PENINSULA. SOME DISCREPANCY LINGERS BETWEEN FORECAST VALUES THIS
AFTERNOON AND OBSERVED TPW PWAT SAT READINGS WITH THE MODELS
OVER-DOING PWAT FCSTS BY ABOUT A TENTH OF AN INCH ATTM.
HOWEVER...QPF FORECAST VALUES REMAIN IN FAIRLY GOOD AGREEMENT ON
TIMING AND AMOUNTS BETWEEN ALL THE MODELS. MAIN FRONTAL FEATURE OFF
THE PARENT LOW AND ASSOCIATED PRECIPITATION BAND WILL SLOWLY WORK
THROUGH SOCAL SUNDAY...AND INTO SOUTHEAST CA BY THE AFTERNOON. THE
UPPER LOW WILL BEGIN TO TRANSITION EASTWARD OVERNIGHT SUNDAY INTO
MONDAY...AS A SECONDARY KICKER SYSTEM QUICKLY DROPS OUT OF THE PAC
NW. MAIN PRECIP FRONTAL BAND...WITH MODERATE TO AT TIMES HEAVY
RAINFALL...WILL TRANSITION FROM PORTIONS OF THE CO RIVER VALLEY AND
WESTERN AZ LATER SUNDAY INTO SOUTH-CENTRAL AZ BY MONDAY MORNING.

RAIN WILL TRANSITION FROM WEST TO EAST DURING THE MONDAY...WITH EVEN
THE THREAT FOR SOME EMBEDDED THUNDERSTORM DEVELOP LATER MONDAY WITH
THE MOVEMENT OF THE UPPER LOW COLD CORE ACROSS AZ. THINK THE
THREAT FOR THUNDER SHOULD WRAP FAIRLY EARLY MONDAY EVENING...BUT DID
EXPAND SLIGHT CHANCE THUNDER MENTION FOR A FEW EXTRA HOURS GIVEN THE
LATEST ROUND OF TIMING ADJUSTMENTS.

THE SECONDARY KICKER SYSTEM QUICKLY SKIRTS DOWN THE WEST COAST AND
DROPS OVER BAJA FOR TUESDAY...NOW PRESENTING A POTENTIALLY DRIER
TUESDAY OVER THE SOUTHWEST DESERTS. GIVEN THE SHORT-TERM STRUGGLES
IN THE MODEL SOLNS...LEFT THE FORECAST POPS FOR TUESDAY AND
WEDNESDAY MAINLY UNTOUCHED. THEY RESULT IN SLIGHT SHOWER CHANCES
LINGER OVER MUCH OF THE SOUTH-CENTRAL AZ DESERTS/HIGHER TERRAIN
TUESDAY AND DRIER CONDITIONS BEGINNING WEDNESDAY. UNSETTLED AND
DRIER NORTHWEST FLOW FILTERS INTO THE AREA FOR THE REMAINDER OF THE
WORK WEEK...WITH ANOTHER SHORTWAVE/CUTOFF FEATURE SKIRTING THE AREA
LATE THURSDAY/FRIDAY. THIS MAY HELP TO KEEP TEMPERATURES ON THE COOL
SIDE...BUT LOOKS TO KEEP OUR AREA DRY AND FREE FROM ANY ADDITIONAL
PRECIP ACTIVITY. TEMPERATURES WILL REACH THEIR LOWEST VALUES ON
MONDAY AND WILL SLOWLY REBOUND BACK INTO THE MID 70S/LOWER 80S BY
LATE NEXT WEEK.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
A SLOW APPROACHING COLD FRONT WILL CONTINUE DRAW LOW LEVEL MOISTURE
INTO THE AREA FROM NORTHERN BAJA THROUGH SUNDAY AFTERNOON. ISOLATED
SHOWERS IN THE PHOENIX VALLEY ARE EXPECTED...WITH A BRIEF HEAVIER
PERIOD AROUND SUNRISE SUNDAY. THEREFORE SCT CLDS BASED NEAR 4 THSD
AGL WITH BKN-OVC CLDS BETWEEN 5-6 THSD AGL WILL CONTINUE THROUGH AT
LEAST 20Z SUN. LIGHT SOUTH WIND IS EXPECTED THROUGH 14Z...INCREASING
TO 10 TO 15 KNOTS FROM 14Z-20Z SUN.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
THROUGH 16Z SUN...SCT CLDS NEAR 6 THSD AGL..BKN CLDS 10-12 THSD AGL.
WEST TO SOUTHWEST WIND 5 TO 10 KNOTS. FROM 16Z SUN TO 20Z SUN...
CLDS LOWERING TO BKN 6 THSD AGL WITH SCT RAIN SHOWERS. LIGHT SOUTH
WIND 5 TO 10 KNOTS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
COOL AND WET CONDITIONS WILL BE PRESENT ON MONDAY AND LIKELY INTO
TUESDAY WITH THE BEST CHANCES FOR WIDESPREAD RAINS ON MONDAY. THERE
WILL BE A CHANCE OF A FEW THUNDERSTORMS ON MONDAY. HUMIDITIES WILL
BE WELL ABOVE TYPICAL VALUES THROUGH TUESDAY BEFORE MINIMUM VALUES
FALL BACK INTO THE TEENS STARTING THURSDAY AFTERNOON. PERIODS OF
BREEZY SOUTHWESTERLY WINDS CAN BE EXPECTED ON MONDAY AND AGAIN ON
WEDNESDAY. HIGH TEMPERATURES ACROSS THE DESERTS WILL ONLY REACH INTO
THE 60S THROUGH WEDNESDAY. HIGH PRESSURE BRINGING WARMER AND DRIER
WEATHER SHOULD MOVE IN STARTING LATER WEDNESDAY AND SHOULD PERSIST
THROUGH THE END OF THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY AFTERNOON
     AZZ021>024.

CA...NONE.

&&

$$

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

DISCUSSION...VASQUEZ/NOLTE
AVIATION...VASQUEZ
FIRE WEATHER...KUHLMAN












000
FXUS65 KPSR 282243
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
342 PM MST SAT FEB 28 2015

...PROLONGED WET WINTER WEATHER EVENT ACROSS THE DESERT SOUTHWEST
SUNDAY THROUGH LATE MONDAY...

&&

.SYNOPSIS...
LOW PRESSURE WILL CONTINUE A SLOW APPROACH OF THE FORECAST
AREA...BRINGING MOISTURE INTO THE REGION ALONG WITH INCREASING
CHANCES OF SHOWERS SUNDAY AND MONDAY. PERIODS OF HEAVY RAIN ARE
POSSIBLE AT TIMES ESPECIALLY SUNDAY NIGHT THROUGH MONDAY AFTERNOON.
COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS STORM WITH BELOW NORMAL
READINGS EXPECTED MONDAY THROUGH LATE WEEK.

&&

.DISCUSSION...
AFTERNOON IR/WV IMAGERY LOOPS SHOW THE UPPER LOW CONTINUING TO
TRAVEL SOUTHWARD THROUGH CA...WITH THE CIRCULATION CENTER NOW SOUTH
OF THE SAN FRANCISCO BAY AREA. DOWNSTREAM FROM THE MAIN UPPER
LOW...UNSETTLED WESTERLY MID AND UPPER JET FLOW SPANS FROM THE CA
COAST AND ACROSS MUCH OF THE SOUTHERN CONUS. SPOTTY LIGHT RAIN
SHOWER COVERAGE CONTINUES ACROSS THE NORTHERN FRINGE OF MARICOPA
COUNTY THIS AFTERNOON. ADDITIONAL AREA OF LIGHT RAIN SHOWERS HAVE
BEGUN TO PERCOLATE WELL EAST OF THE PHOENIX METRO...ALONG THE US60
CORRIDOR. IN ADDITION...STRONG SURFACE WINDS CONTINUE ACROSS MUCH OF
THE REGION...ESPECIALLY THE SOUTHEAST CA FORECAST ZONES...WITH MANY
SITES REPORTING GUSTS INTO THE 30 KT/MID 30 MPH RANGE. STRONG WINDS
WILL EVENTUALLY TAPER BACK IN SPEEDS LATER INTO THE EVENING WHILE
STILL REMAINING SLIGHTLY ELEVATED OVER AREA RIDGETOPS. SPOTTY SHOWER
COVERAGE WILL ALSO CONTINUE...ESPECIALLY FOR THE FOOTHILL/HIGH
TERRAIN LOCALES NORTH/EAST OF PHOENIX WITH ADDITIONAL ACCUMULATIONS
ON THE ORDER OF A COUPLE HUNDREDTHS TO POSSIBLE 0.10" OR SO. POP
FORECASTS FOR THE REST OF THE AFTERNOON KEEP ISOLATED SHOWER MENTION
OVER PORTIONS OF THE SOUTH-CENTRAL AZ DESERTS...WITH INCREASING
PERCENTAGES AND COVERAGE BECOMING SCATTERED THE FURTHER
NORTH/NORTHEAST OF PHOENIX YOU GO.

IN GENERAL...VERY LITTLE HAS CHANGED WITH THE OVERALL NARRATIVE OF
SENSIBLE WEATHER IMPACTS ASSOCIATED WITH THIS SYSTEM FOR SUNDAY AND
THE EARLY WORK WEEK. HOWEVER...FORECAST SOLNS HAVE ONCE AGAIN
SHIFTED THE SIGNIFICANT IMPACT WINDOWS OUT BY ANOTHER 6-HRS OR SO.
THE TRANSLATES TO THE WINDOWS WITH MODERATE TO HEAVY RAINFALL
CONCERNS OVER SOUTHEAST CA LATER INTO THE DAY SUNDAY...MORE LIKELY
AFTER 18Z. IN ADDITION...THE WINDOW FOR MODERATE TO HEAVY RAINFALL
OVER THE SOUTH-CENTRAL AZ DESERTS/FOOTHILLS HAS SHIFTED PRIMARILY TO
MONDAY. ONLY SLIGHT ADJUSTMENTS WERE WORKED INTO THE QPF
GRIDS...WITH UPWARD NUDGES OF STORM TOTAL VALUES PUSHING 2 INCHES
POSSIBLY OVER THE FAR NORTHEAST MARICOPA COUNTY CORNER AND 1.5 INCH
VALUES FOR WICKENBURG AND NORTHWEST MARICOPA COUNTY. AROUND 1 INCH
STORM TOTAL HOLDS ACROSS THE PHOENIX METRO WITH 0.60 TO 0.90 OR SO
READINGS POSSIBLE OUT ALONG THE LOWER CO RIVER VALLEY AND SOUTHEAST
CA.

THE UPPER LOW WILL CONTINUE TO DIG DOWN TO THE SOCAL COAST THROUGH
THE EVENING...STALLING OUT WEST OF SAN DIEGO/LA FOR MUCH OF THE DAY
SUNDAY. MEANWHILE...DECENT BAND OF ELEVATED SUBTROPIC MOISTURE WILL
BE DRAWN NORTHWARD TOWARDS THE UPPER LOW AND OVER THE BAJA
PENINSULA. SOME DISCREPANCY LINGERS BETWEEN FORECAST VALUES THIS
AFTERNOON AND OBSERVED TPW PWAT SAT READINGS WITH THE MODELS
OVER-DOING PWAT FCSTS BY ABOUT A TENTH OF AN INCH ATTM.
HOWEVER...QPF FORECAST VALUES REMAIN IN FAIRLY GOOD AGREEMENT ON
TIMING AND AMOUNTS BETWEEN ALL THE MODELS. MAIN FRONTAL FEATURE OFF
THE PARENT LOW AND ASSOCIATED PRECIPITATION BAND WILL SLOWLY WORK
THROUGH SOCAL SUNDAY...AND INTO SOUTHEAST CA BY THE AFTERNOON. THE
UPPER LOW WILL BEGIN TO TRANSITION EASTWARD OVERNIGHT SUNDAY INTO
MONDAY...AS A SECONDARY KICKER SYSTEM QUICKLY DROPS OUT OF THE PAC
NW. MAIN PRECIP FRONTAL BAND...WITH MODERATE TO AT TIMES HEAVY
RAINFALL...WILL TRANSITION FROM PORTIONS OF THE CO RIVER VALLEY AND
WESTERN AZ LATER SUNDAY INTO SOUTH-CENTRAL AZ BY MONDAY MORNING.

RAIN WILL TRANSITION FROM WEST TO EAST DURING THE MONDAY...WITH EVEN
THE THREAT FOR SOME EMBEDDED THUNDERSTORM DEVELOP LATER MONDAY WITH
THE MOVEMENT OF THE UPPER LOW COLD CORE ACROSS AZ. THINK THE
THREAT FOR THUNDER SHOULD WRAP FAIRLY EARLY MONDAY EVENING...BUT DID
EXPAND SLIGHT CHANCE THUNDER MENTION FOR A FEW EXTRA HOURS GIVEN THE
LATEST ROUND OF TIMING ADJUSTMENTS.

THE SECONDARY KICKER SYSTEM QUICKLY SKIRTS DOWN THE WEST COAST AND
DROPS OVER BAJA FOR TUESDAY...NOW PRESENTING A POTENTIALLY DRIER
TUESDAY OVER THE SOUTHWEST DESERTS. GIVEN THE SHORT-TERM STRUGGLES
IN THE MODEL SOLNS...LEFT THE FORECAST POPS FOR TUESDAY AND
WEDNESDAY MAINLY UNTOUCHED. THEY RESULT IN SLIGHT SHOWER CHANCES
LINGER OVER MUCH OF THE SOUTH-CENTRAL AZ DESERTS/HIGHER TERRAIN
TUESDAY AND DRIER CONDITIONS BEGINNING WEDNESDAY. UNSETTLED AND
DRIER NORTHWEST FLOW FILTERS INTO THE AREA FOR THE REMAINDER OF THE
WORK WEEK...WITH ANOTHER SHORTWAVE/CUTOFF FEATURE SKIRTING THE AREA
LATE THURSDAY/FRIDAY. THIS MAY HELP TO KEEP TEMPERATURES ON THE COOL
SIDE...BUT LOOKS TO KEEP OUR AREA DRY AND FREE FROM ANY ADDITIONAL
PRECIP ACTIVITY. TEMPERATURES WILL REACH THEIR LOWEST VALUES ON
MONDAY AND WILL SLOWLY REBOUND BACK INTO THE MID 70S/LOWER 80S BY
LATE NEXT WEEK.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
LOW PRESSURE SYSTEM CENTERED NEAR S.F. BAY AREA WILL CONTINUE TO
SPREAD LOWER LEVEL MOISTURE OVER THE AREA TONIGHT AND SUNDAY FOR
SCT-BKN DECKS WITH BASES AT FL050-070 DECREASING TO FL040-060 AFTER
06Z. ONLY SPOTTY LIGHT SHOWERS...MAINLY FOOTHILLS/HIGHER TERRAIN
WITH HIGHER MOUNTAINS OBSCURED...THROUGH TONIGHT WITH SOMEWHAT MORE
AREAL COVERAGE OF LIGHT SHOWERS DEVELOPING SUNDAY. SURFACE WINDS
WILL FAVOR SOUTHWEST INTO THE EVENING BEFORE TRENDING SOUTHEAST
OVERNIGHT. ANTICIPATE SOUTHERLY COMPONENT TO PREVAIL THROUGH THE DAY
SUNDAY WITH GUSTS OF 20-25 KTS IN THE AFTERNOON.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
SOUTHWEST WINDS GUSTING 25-30 KNOTS WILL SLOWLY DECREASE EARLY THIS
EVENING. MUCH LIGHTER SURFACE WINDS DURING THE DAY SUNDAY.
SIGNIFICANT SOUTHWEST AND WEST WINDS ABOVE THE SURFACE WILL CONTINUE
OVERNIGHT. SCT...LOCALLY BKN...CLOUD BASES FL060-080 WILL DECREASE
THIS EVENING BEFORE MORE WIDESPREAD CEILINGS DEVELOP DURING THE
DAYTIME HOURS ALONG WITH SCATTERED SHOWERS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
COOL AND WET CONDITIONS WILL BE PRESENT ON MONDAY AND LIKELY INTO
TUESDAY WITH THE BEST CHANCES FOR WIDESPREAD RAINS ON MONDAY. THERE
WILL BE A CHANCE OF A FEW THUNDERSTORMS ON MONDAY. HUMIDITIES WILL
BE WELL ABOVE TYPICAL VALUES THROUGH TUESDAY BEFORE MINIMUM VALUES
FALL BACK INTO THE TEENS STARTING THURSDAY AFTERNOON. PERIODS OF
BREEZY SOUTHWESTERLY WINDS CAN BE EXPECTED ON MONDAY AND AGAIN ON
WEDNESDAY. HIGH TEMPERATURES ACROSS THE DESERTS WILL ONLY REACH INTO
THE 60S THROUGH WEDNESDAY. HIGH PRESSURE BRINGING WARMER AND DRIER
WEATHER SHOULD MOVE IN STARTING LATER WEDNESDAY AND SHOULD PERSIST
THROUGH THE END OF THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY AFTERNOON
     AZZ021>024.

CA...NONE.

&&

$$

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

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









000
FXUS65 KPSR 282243
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
342 PM MST SAT FEB 28 2015

...PROLONGED WET WINTER WEATHER EVENT ACROSS THE DESERT SOUTHWEST
SUNDAY THROUGH LATE MONDAY...

&&

.SYNOPSIS...
LOW PRESSURE WILL CONTINUE A SLOW APPROACH OF THE FORECAST
AREA...BRINGING MOISTURE INTO THE REGION ALONG WITH INCREASING
CHANCES OF SHOWERS SUNDAY AND MONDAY. PERIODS OF HEAVY RAIN ARE
POSSIBLE AT TIMES ESPECIALLY SUNDAY NIGHT THROUGH MONDAY AFTERNOON.
COOLER TEMPERATURES WILL ALSO ACCOMPANY THIS STORM WITH BELOW NORMAL
READINGS EXPECTED MONDAY THROUGH LATE WEEK.

&&

.DISCUSSION...
AFTERNOON IR/WV IMAGERY LOOPS SHOW THE UPPER LOW CONTINUING TO
TRAVEL SOUTHWARD THROUGH CA...WITH THE CIRCULATION CENTER NOW SOUTH
OF THE SAN FRANCISCO BAY AREA. DOWNSTREAM FROM THE MAIN UPPER
LOW...UNSETTLED WESTERLY MID AND UPPER JET FLOW SPANS FROM THE CA
COAST AND ACROSS MUCH OF THE SOUTHERN CONUS. SPOTTY LIGHT RAIN
SHOWER COVERAGE CONTINUES ACROSS THE NORTHERN FRINGE OF MARICOPA
COUNTY THIS AFTERNOON. ADDITIONAL AREA OF LIGHT RAIN SHOWERS HAVE
BEGUN TO PERCOLATE WELL EAST OF THE PHOENIX METRO...ALONG THE US60
CORRIDOR. IN ADDITION...STRONG SURFACE WINDS CONTINUE ACROSS MUCH OF
THE REGION...ESPECIALLY THE SOUTHEAST CA FORECAST ZONES...WITH MANY
SITES REPORTING GUSTS INTO THE 30 KT/MID 30 MPH RANGE. STRONG WINDS
WILL EVENTUALLY TAPER BACK IN SPEEDS LATER INTO THE EVENING WHILE
STILL REMAINING SLIGHTLY ELEVATED OVER AREA RIDGETOPS. SPOTTY SHOWER
COVERAGE WILL ALSO CONTINUE...ESPECIALLY FOR THE FOOTHILL/HIGH
TERRAIN LOCALES NORTH/EAST OF PHOENIX WITH ADDITIONAL ACCUMULATIONS
ON THE ORDER OF A COUPLE HUNDREDTHS TO POSSIBLE 0.10" OR SO. POP
FORECASTS FOR THE REST OF THE AFTERNOON KEEP ISOLATED SHOWER MENTION
OVER PORTIONS OF THE SOUTH-CENTRAL AZ DESERTS...WITH INCREASING
PERCENTAGES AND COVERAGE BECOMING SCATTERED THE FURTHER
NORTH/NORTHEAST OF PHOENIX YOU GO.

IN GENERAL...VERY LITTLE HAS CHANGED WITH THE OVERALL NARRATIVE OF
SENSIBLE WEATHER IMPACTS ASSOCIATED WITH THIS SYSTEM FOR SUNDAY AND
THE EARLY WORK WEEK. HOWEVER...FORECAST SOLNS HAVE ONCE AGAIN
SHIFTED THE SIGNIFICANT IMPACT WINDOWS OUT BY ANOTHER 6-HRS OR SO.
THE TRANSLATES TO THE WINDOWS WITH MODERATE TO HEAVY RAINFALL
CONCERNS OVER SOUTHEAST CA LATER INTO THE DAY SUNDAY...MORE LIKELY
AFTER 18Z. IN ADDITION...THE WINDOW FOR MODERATE TO HEAVY RAINFALL
OVER THE SOUTH-CENTRAL AZ DESERTS/FOOTHILLS HAS SHIFTED PRIMARILY TO
MONDAY. ONLY SLIGHT ADJUSTMENTS WERE WORKED INTO THE QPF
GRIDS...WITH UPWARD NUDGES OF STORM TOTAL VALUES PUSHING 2 INCHES
POSSIBLY OVER THE FAR NORTHEAST MARICOPA COUNTY CORNER AND 1.5 INCH
VALUES FOR WICKENBURG AND NORTHWEST MARICOPA COUNTY. AROUND 1 INCH
STORM TOTAL HOLDS ACROSS THE PHOENIX METRO WITH 0.60 TO 0.90 OR SO
READINGS POSSIBLE OUT ALONG THE LOWER CO RIVER VALLEY AND SOUTHEAST
CA.

THE UPPER LOW WILL CONTINUE TO DIG DOWN TO THE SOCAL COAST THROUGH
THE EVENING...STALLING OUT WEST OF SAN DIEGO/LA FOR MUCH OF THE DAY
SUNDAY. MEANWHILE...DECENT BAND OF ELEVATED SUBTROPIC MOISTURE WILL
BE DRAWN NORTHWARD TOWARDS THE UPPER LOW AND OVER THE BAJA
PENINSULA. SOME DISCREPANCY LINGERS BETWEEN FORECAST VALUES THIS
AFTERNOON AND OBSERVED TPW PWAT SAT READINGS WITH THE MODELS
OVER-DOING PWAT FCSTS BY ABOUT A TENTH OF AN INCH ATTM.
HOWEVER...QPF FORECAST VALUES REMAIN IN FAIRLY GOOD AGREEMENT ON
TIMING AND AMOUNTS BETWEEN ALL THE MODELS. MAIN FRONTAL FEATURE OFF
THE PARENT LOW AND ASSOCIATED PRECIPITATION BAND WILL SLOWLY WORK
THROUGH SOCAL SUNDAY...AND INTO SOUTHEAST CA BY THE AFTERNOON. THE
UPPER LOW WILL BEGIN TO TRANSITION EASTWARD OVERNIGHT SUNDAY INTO
MONDAY...AS A SECONDARY KICKER SYSTEM QUICKLY DROPS OUT OF THE PAC
NW. MAIN PRECIP FRONTAL BAND...WITH MODERATE TO AT TIMES HEAVY
RAINFALL...WILL TRANSITION FROM PORTIONS OF THE CO RIVER VALLEY AND
WESTERN AZ LATER SUNDAY INTO SOUTH-CENTRAL AZ BY MONDAY MORNING.

RAIN WILL TRANSITION FROM WEST TO EAST DURING THE MONDAY...WITH EVEN
THE THREAT FOR SOME EMBEDDED THUNDERSTORM DEVELOP LATER MONDAY WITH
THE MOVEMENT OF THE UPPER LOW COLD CORE ACROSS AZ. THINK THE
THREAT FOR THUNDER SHOULD WRAP FAIRLY EARLY MONDAY EVENING...BUT DID
EXPAND SLIGHT CHANCE THUNDER MENTION FOR A FEW EXTRA HOURS GIVEN THE
LATEST ROUND OF TIMING ADJUSTMENTS.

THE SECONDARY KICKER SYSTEM QUICKLY SKIRTS DOWN THE WEST COAST AND
DROPS OVER BAJA FOR TUESDAY...NOW PRESENTING A POTENTIALLY DRIER
TUESDAY OVER THE SOUTHWEST DESERTS. GIVEN THE SHORT-TERM STRUGGLES
IN THE MODEL SOLNS...LEFT THE FORECAST POPS FOR TUESDAY AND
WEDNESDAY MAINLY UNTOUCHED. THEY RESULT IN SLIGHT SHOWER CHANCES
LINGER OVER MUCH OF THE SOUTH-CENTRAL AZ DESERTS/HIGHER TERRAIN
TUESDAY AND DRIER CONDITIONS BEGINNING WEDNESDAY. UNSETTLED AND
DRIER NORTHWEST FLOW FILTERS INTO THE AREA FOR THE REMAINDER OF THE
WORK WEEK...WITH ANOTHER SHORTWAVE/CUTOFF FEATURE SKIRTING THE AREA
LATE THURSDAY/FRIDAY. THIS MAY HELP TO KEEP TEMPERATURES ON THE COOL
SIDE...BUT LOOKS TO KEEP OUR AREA DRY AND FREE FROM ANY ADDITIONAL
PRECIP ACTIVITY. TEMPERATURES WILL REACH THEIR LOWEST VALUES ON
MONDAY AND WILL SLOWLY REBOUND BACK INTO THE MID 70S/LOWER 80S BY
LATE NEXT WEEK.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
LOW PRESSURE SYSTEM CENTERED NEAR S.F. BAY AREA WILL CONTINUE TO
SPREAD LOWER LEVEL MOISTURE OVER THE AREA TONIGHT AND SUNDAY FOR
SCT-BKN DECKS WITH BASES AT FL050-070 DECREASING TO FL040-060 AFTER
06Z. ONLY SPOTTY LIGHT SHOWERS...MAINLY FOOTHILLS/HIGHER TERRAIN
WITH HIGHER MOUNTAINS OBSCURED...THROUGH TONIGHT WITH SOMEWHAT MORE
AREAL COVERAGE OF LIGHT SHOWERS DEVELOPING SUNDAY. SURFACE WINDS
WILL FAVOR SOUTHWEST INTO THE EVENING BEFORE TRENDING SOUTHEAST
OVERNIGHT. ANTICIPATE SOUTHERLY COMPONENT TO PREVAIL THROUGH THE DAY
SUNDAY WITH GUSTS OF 20-25 KTS IN THE AFTERNOON.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
SOUTHWEST WINDS GUSTING 25-30 KNOTS WILL SLOWLY DECREASE EARLY THIS
EVENING. MUCH LIGHTER SURFACE WINDS DURING THE DAY SUNDAY.
SIGNIFICANT SOUTHWEST AND WEST WINDS ABOVE THE SURFACE WILL CONTINUE
OVERNIGHT. SCT...LOCALLY BKN...CLOUD BASES FL060-080 WILL DECREASE
THIS EVENING BEFORE MORE WIDESPREAD CEILINGS DEVELOP DURING THE
DAYTIME HOURS ALONG WITH SCATTERED SHOWERS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
COOL AND WET CONDITIONS WILL BE PRESENT ON MONDAY AND LIKELY INTO
TUESDAY WITH THE BEST CHANCES FOR WIDESPREAD RAINS ON MONDAY. THERE
WILL BE A CHANCE OF A FEW THUNDERSTORMS ON MONDAY. HUMIDITIES WILL
BE WELL ABOVE TYPICAL VALUES THROUGH TUESDAY BEFORE MINIMUM VALUES
FALL BACK INTO THE TEENS STARTING THURSDAY AFTERNOON. PERIODS OF
BREEZY SOUTHWESTERLY WINDS CAN BE EXPECTED ON MONDAY AND AGAIN ON
WEDNESDAY. HIGH TEMPERATURES ACROSS THE DESERTS WILL ONLY REACH INTO
THE 60S THROUGH WEDNESDAY. HIGH PRESSURE BRINGING WARMER AND DRIER
WEATHER SHOULD MOVE IN STARTING LATER WEDNESDAY AND SHOULD PERSIST
THROUGH THE END OF THE WEEK.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLOOD WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY AFTERNOON
     AZZ021>024.

CA...NONE.

&&

$$

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

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








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