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000
FXUS65 KPSR 241000
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
300 AM MST THU APR 24 2014

.SYNOPSIS...
WARMER TEMPERATURES ARE EXPECTED TODAY AND FRIDAY. HOWEVER
CONSIDERABLE HIGH CLOUDS AND BREEZY CONDITIONS FRIDAY...WILL SIGNAL
THE APPROACH OF A STRONG COLD FRONT FOR SATURDAY MORNING. THE COLD
FRONT SATURDAY WILL PRODUCE VERY WINDY CONDITIONS ACROSS THE
REGION...ALONG WITH AREAS OF BLOWING DUST AND SAND. A CHANCE OF
SHOWERS AND POSSIBLY A THUNDERSTORM WILL DEVELOP MAINLY OVER
PORTIONS OF SOUTH CENTRAL ARIZONA NEAR PHOENIX. MUCH COOLER
TEMPERATURES ARE ALSO EXPECTED SATURDAY. DRY WEATHER...WITH A SLOW
WARMING TREND WILL DEVELOP SUNDAY THROUGH THE MIDDLE OF NEXT WEEK.

&&

.DISCUSSION...
NOTE: A STRONG COLD FRONT WILL PRODUCE HIGH WINDS IN SOUTHEAST CA
LATE FRIDAY NIGHT/SATURDAY MORNING...AND VERY WINDY CONDITIONS
ELSEWHERE IN SOUTHWEST AND SOUTH CENTRAL AZ SATURDAY MORNING.

TODAY AND FRIDAY...
A SHORTWAVE RIDGE TODAY WILL PRODUCE NEARLY CLOUDLESS SKIES AND
SLIGHTLY ABOVE NORMAL AFTERNOON TEMPERATURES...I.E. LOWER 90S ON THE
DESERTS.  ON FRIDAY...CONSIDERABLE HIGH CLOUDS...SLIGHTLY WARMER
TEMPERATURES...AND AFTERNOON BREEZES WILL DEVELOP. HIGH CLOUDS AND
BREEZES WILL SIGNAL THE APPROACH OF A STRONG PACIFIC TROF/COLD FRONT
FOR SATURDAY.

SATURDAY...
MODELS CONTINUE TO MOVE A POTENT SPRING STORM INTO ARIZONA SATURDAY.
WE PREFER THE GFS SOLUTION FOR SEVERAL REASONS. ONE...THE WAVE
PATTERN OVER THE PACIFIC IS PROGRESSIVE. TWO...A STRONG SPLIT FLOW
ALOFT DEVELOPS JUST OFF THE WEST COAST LIMITING AN OVERLY DEEP
DIGGING TROF. THREE...THE CENTRAL AND EASTERN U.S. IS FREE FROM ANY
BLOCKING SYSTEMS DOWNSTREAM.

THE MAGNITUDE OF THE GFS 12 HR 500 MB HEIGHT FALLS...NEARLY 200
METERS OVER JOSHUA TREE N.P. ZONE 30 AT 12Z SAT...AND ANOTHER 160
METERS NEAR PRESCOTT JUST BEFORE 18Z INDICATE SIGNIFICANT MASS FIELD
CHANGES.THEREFORE...THE GREATEST IMPACT OVER OUR FORECAST AREA WILL
BE WIND. GUSTS BETWEEN 35 AND 50 MPH ARE LIKELY IN SOUTHEAST CA LATE
FRIDAY NIGHT/EARLY SATURDAY MORNING WITH THE COLD FRONT. GUSTY WINDS
IN THE 30 TO 45 MPH RANGE WILL SPREAD TOWARD PHOENIX BY LATE
SATURDAY MORNING/EARLY AFTERNOON. AREAS OF BLOWING DUST AND SAND ARE
EXPECTED.

STRONG VERTICAL MOTION/UPPER LEVEL STORM DYNAMICS WILL MOSTLY BE
CONFINED TO AREAS SKIRTING THE FAR NORTHERN PORTIONS OF OUR
FORECAST AREA...I.E. THE NORTHERN PORTIONS OF LA PAZ...NORTHERN
MARICOPA...AND NORTHERN GILA COUNTIES. THESE AREAS COULD SEE A
THREAT OF SHOWERS AND POSSIBLE THUNDERSTORM. THE BEST CHANCE OF
SHOWERS HOWEVER WILL DEVELOP OVER SOUTHERN GILA COUNTY.

THIS IS A FAST MOVING TROF STORM MOST STORM SUPPORT FORECAST TO MOVE
INTO NORTHWEST NEW MEXICO BY EARLY SATURDAY EVENING.

SUNDAY AND MONDAY...
DRY NORTHWEST FLOW ALOFT WITH NEARLY CLOUDLESS SKIES...LIGHTER
WIND...AND SLOWLY WARMING AFTERNOON TEMPERATURES ARE EXPECTED THIS
PERIOD.

TUESDAY THROUGH FRIDAY...
DRY WEATHER WITH ABOVE NORMAL TEMPERATURES ARE FORECAST. THE ONLY
CAVEAT WILL BE GUSTY NORTH WINDS OVER THE FORECAST AREA...ESPECIALLY
DOWN THE COLORADO RIVER VALLEY TUESDAY AND WEDNESDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
TYPICAL EASTERLY DIURNAL WINDS THIS MORNING TO BECOME WESTERLY THIS
AFTERNOON AND EARLY EVENING...THEN REVERT BACK TO EASTERLY LATE
TONIGHT. WIND SPEEDS TO REMAIN MAINLY AOB 8 KTS THROUGH THE TAF
PERIOD. ASIDE FROM SOME HIGH CLOUDINESS FROM TIME-TO-TIME...SKIES TO
REMAIN MOSTLY CLEAR. NO AVIATION CONCERNS.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
CURRENT LIGHT WINDS THIS MORNING TO BECOME SOUTHERLY TO
SOUTHWESTERLY FROM THIS AFTERNOON ONWARD INTO TONIGHT WITH SPEEDS
MAINLY IN THE 7-12 KNOT RANGE. ASIDE FROM A FEW HIGH CLOUDS SKIES
SHOULD BE CLEAR. NO AVIATION CONCERNS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
RATHER STRONG...AND COLD UPPER LOW (FOR THIS TIME OF YEAR) TO
PRODUCE STRONG AND GUSTY WINDS...AND BRING MUCH COOLER TEMPERATURES
TO THE REGION ON SATURDAY. ALTHOUGH FIRE DANGER LEVELS WILL BE
ELEVATED BY THESE STRONG WINDS...INCREASING MOISTURE LEVELS ARE
EXPECTED TO KEEP FIRE DANGER LEVELS BELOW CRITICAL THRESHOLDS AT
MOST LOCATIONS. MUCH LIGHTER WINDS ARE THEN EXPECTED FROM SUNDAY
ONWARD...WITH TEMPERATURES SLOWLY RECOVERING BACK TOWARD NORMAL
VALUES. OVERNIGHT HUMIDITY RECOVERIES WILL GRADUALLY DETERIORATE AS
THE WEEK PROGRESSES.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING
     AZZ020-025.

CA...FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING
     CAZ031.

$$

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

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












000
FXUS65 KPSR 241000
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
300 AM MST THU APR 24 2014

.SYNOPSIS...
WARMER TEMPERATURES ARE EXPECTED TODAY AND FRIDAY. HOWEVER
CONSIDERABLE HIGH CLOUDS AND BREEZY CONDITIONS FRIDAY...WILL SIGNAL
THE APPROACH OF A STRONG COLD FRONT FOR SATURDAY MORNING. THE COLD
FRONT SATURDAY WILL PRODUCE VERY WINDY CONDITIONS ACROSS THE
REGION...ALONG WITH AREAS OF BLOWING DUST AND SAND. A CHANCE OF
SHOWERS AND POSSIBLY A THUNDERSTORM WILL DEVELOP MAINLY OVER
PORTIONS OF SOUTH CENTRAL ARIZONA NEAR PHOENIX. MUCH COOLER
TEMPERATURES ARE ALSO EXPECTED SATURDAY. DRY WEATHER...WITH A SLOW
WARMING TREND WILL DEVELOP SUNDAY THROUGH THE MIDDLE OF NEXT WEEK.

&&

.DISCUSSION...
NOTE: A STRONG COLD FRONT WILL PRODUCE HIGH WINDS IN SOUTHEAST CA
LATE FRIDAY NIGHT/SATURDAY MORNING...AND VERY WINDY CONDITIONS
ELSEWHERE IN SOUTHWEST AND SOUTH CENTRAL AZ SATURDAY MORNING.

TODAY AND FRIDAY...
A SHORTWAVE RIDGE TODAY WILL PRODUCE NEARLY CLOUDLESS SKIES AND
SLIGHTLY ABOVE NORMAL AFTERNOON TEMPERATURES...I.E. LOWER 90S ON THE
DESERTS.  ON FRIDAY...CONSIDERABLE HIGH CLOUDS...SLIGHTLY WARMER
TEMPERATURES...AND AFTERNOON BREEZES WILL DEVELOP. HIGH CLOUDS AND
BREEZES WILL SIGNAL THE APPROACH OF A STRONG PACIFIC TROF/COLD FRONT
FOR SATURDAY.

SATURDAY...
MODELS CONTINUE TO MOVE A POTENT SPRING STORM INTO ARIZONA SATURDAY.
WE PREFER THE GFS SOLUTION FOR SEVERAL REASONS. ONE...THE WAVE
PATTERN OVER THE PACIFIC IS PROGRESSIVE. TWO...A STRONG SPLIT FLOW
ALOFT DEVELOPS JUST OFF THE WEST COAST LIMITING AN OVERLY DEEP
DIGGING TROF. THREE...THE CENTRAL AND EASTERN U.S. IS FREE FROM ANY
BLOCKING SYSTEMS DOWNSTREAM.

THE MAGNITUDE OF THE GFS 12 HR 500 MB HEIGHT FALLS...NEARLY 200
METERS OVER JOSHUA TREE N.P. ZONE 30 AT 12Z SAT...AND ANOTHER 160
METERS NEAR PRESCOTT JUST BEFORE 18Z INDICATE SIGNIFICANT MASS FIELD
CHANGES.THEREFORE...THE GREATEST IMPACT OVER OUR FORECAST AREA WILL
BE WIND. GUSTS BETWEEN 35 AND 50 MPH ARE LIKELY IN SOUTHEAST CA LATE
FRIDAY NIGHT/EARLY SATURDAY MORNING WITH THE COLD FRONT. GUSTY WINDS
IN THE 30 TO 45 MPH RANGE WILL SPREAD TOWARD PHOENIX BY LATE
SATURDAY MORNING/EARLY AFTERNOON. AREAS OF BLOWING DUST AND SAND ARE
EXPECTED.

STRONG VERTICAL MOTION/UPPER LEVEL STORM DYNAMICS WILL MOSTLY BE
CONFINED TO AREAS SKIRTING THE FAR NORTHERN PORTIONS OF OUR
FORECAST AREA...I.E. THE NORTHERN PORTIONS OF LA PAZ...NORTHERN
MARICOPA...AND NORTHERN GILA COUNTIES. THESE AREAS COULD SEE A
THREAT OF SHOWERS AND POSSIBLE THUNDERSTORM. THE BEST CHANCE OF
SHOWERS HOWEVER WILL DEVELOP OVER SOUTHERN GILA COUNTY.

THIS IS A FAST MOVING TROF STORM MOST STORM SUPPORT FORECAST TO MOVE
INTO NORTHWEST NEW MEXICO BY EARLY SATURDAY EVENING.

SUNDAY AND MONDAY...
DRY NORTHWEST FLOW ALOFT WITH NEARLY CLOUDLESS SKIES...LIGHTER
WIND...AND SLOWLY WARMING AFTERNOON TEMPERATURES ARE EXPECTED THIS
PERIOD.

TUESDAY THROUGH FRIDAY...
DRY WEATHER WITH ABOVE NORMAL TEMPERATURES ARE FORECAST. THE ONLY
CAVEAT WILL BE GUSTY NORTH WINDS OVER THE FORECAST AREA...ESPECIALLY
DOWN THE COLORADO RIVER VALLEY TUESDAY AND WEDNESDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
TYPICAL EASTERLY DIURNAL WINDS THIS MORNING TO BECOME WESTERLY THIS
AFTERNOON AND EARLY EVENING...THEN REVERT BACK TO EASTERLY LATE
TONIGHT. WIND SPEEDS TO REMAIN MAINLY AOB 8 KTS THROUGH THE TAF
PERIOD. ASIDE FROM SOME HIGH CLOUDINESS FROM TIME-TO-TIME...SKIES TO
REMAIN MOSTLY CLEAR. NO AVIATION CONCERNS.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
CURRENT LIGHT WINDS THIS MORNING TO BECOME SOUTHERLY TO
SOUTHWESTERLY FROM THIS AFTERNOON ONWARD INTO TONIGHT WITH SPEEDS
MAINLY IN THE 7-12 KNOT RANGE. ASIDE FROM A FEW HIGH CLOUDS SKIES
SHOULD BE CLEAR. NO AVIATION CONCERNS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
RATHER STRONG...AND COLD UPPER LOW (FOR THIS TIME OF YEAR) TO
PRODUCE STRONG AND GUSTY WINDS...AND BRING MUCH COOLER TEMPERATURES
TO THE REGION ON SATURDAY. ALTHOUGH FIRE DANGER LEVELS WILL BE
ELEVATED BY THESE STRONG WINDS...INCREASING MOISTURE LEVELS ARE
EXPECTED TO KEEP FIRE DANGER LEVELS BELOW CRITICAL THRESHOLDS AT
MOST LOCATIONS. MUCH LIGHTER WINDS ARE THEN EXPECTED FROM SUNDAY
ONWARD...WITH TEMPERATURES SLOWLY RECOVERING BACK TOWARD NORMAL
VALUES. OVERNIGHT HUMIDITY RECOVERIES WILL GRADUALLY DETERIORATE AS
THE WEEK PROGRESSES.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING
     AZZ020-025.

CA...FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING
     CAZ031.

$$

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

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













000
FXUS65 KPSR 240355
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
855 PM MST WED APR 23 2014

.SYNOPSIS...
WARMER TEMPERATURES WILL MAKE A RETURN THURSDAY AND FRIDAY.
ANOTHER...MUCH STRONGER LOW PRESSURE SYSTEM WILL THEN AFFECT THE
REGION FROM FRIDAY ONWARD INTO THE UPCOMING WEEKEND. BREEZY TO WINDY
CONDITIONS CAN BE EXPECTED ALONG WITH MUCH COOLER TEMPERATURES ON
SATURDAY. THERE IS ALSO A CHANCE OF SHOWERS LATE FRIDAY NIGHT INTO
SATURDAY NIGHT...MAINLY FOR THE HIGHER TERRAIN OF SOUTH-CENTRAL
ARIZONA. HIGH PRESSURE BUILDING BACK NORTHWARD OVER THE WESTERN US
IS THEN EXPECTED TO BRING WARMER TEMPERATURES FOR THE EARLY AND
MIDDLE PARTS OF NEXT WEEK.

&&

.DISCUSSION...
COOLER BUT CONTINUED BREEZY CONDITIONS LINGERED TODAY IN THE WAKE OF
THE PASSING SHORTWAVE IMPULSE...WHICH HAS NOW CLEAR THE FOUR CORNER
AND CLEARING THE ROCKIES FRONT RANGE THIS EVENING. WHILE SURFACE
CONDITIONS IN TERMS OF DEWPOINTS HAVE DRIED SUBSTANTIALLY
TODAY...WITH SINGLE DIGITS TO LOW 10S OBSERVATIONS...WATER VAPOR
IMAGERY AND UPSTREAM RAOBS SHOW SOME HIGH LEVEL MOISTURE STREAMING
THROUGH THE SUBTLE RIDGE HEIGHTS TO OUR WEST. PATCHES OF HIGH CLOUDS
WILL CONTINUE TO STREAM FROM NORTHWEST TO SOUTHEAST TONIGHT...AT
MOST GENERATING BRIEF PERIODS OF PARTLY CLOUDY SKIES. SURFACE TEMPS
RUNNING 7 TO 10 DEGREES COOLER THAN THIS TIME TUESDAY EVENING...SO
EVEN WITH THE QUICK-PASSING CLOUDS...THINK MIN T FORECAST FOR
TONIGHT IS IN GOOD SHAPE. NO MAJOR UPDATES NEEDED...REMAINDER
OF THE DISCUSSION STILL APPLIES.

&&

.PREVIOUS DISCUSSION /ISSUED AT 255 PM MST/PDT/...
SHORT-WAVE RIDGE WILL BUILD IN OVERNIGHT...RESULTING IN MOSTLY CLEAR
SKIES AND LIGHT WINDS. THIS WILL PROMOTE EFFICIENT RADIATIONAL
COOLING AND TEMPERATURES NEAR OR EVEN SLIGHTLY BELOW NORMAL.

REBOUND IN TEMPERATURES IS EXPECTED THURSDAY AS A SHORT-WAVE RIDGE
IN THE SUBTROPICAL EASTERN PACIFIC BUILDS EASTWARD. ATTENTION WILL
THEN TURN TO A DEEPENING LOW PRESSURE SYSTEM ALONG THE WEST COAST
FRIDAY. BIGGEST IMPACT ACROSS THE FORECAST AREA WILL BE AN INCREASE
IN WIND AHEAD OF THIS SYSTEM. WINDS WILL BE STRONGEST ACROSS SE CA
WHERE GUSTS TO 35 MPH WILL BE POSSIBLE AND UP TO 30 MPH ACROSS
SOUTH-CENTRAL AZ INCLUDING THE PHOENIX METRO AREA.

PREVIOUS DISCUSSION /ISSUED AT 225 AM MST/PDT/...
THE MODELS ARE ALL NOW SHOWING VERY SHARP HEIGHT FALLS AND
TEMPERATURE DROPS AS THIS SYSTEM MOVES THROUGH...WITH 500MB HEIGHTS
OVER THE PHX AREA FALLING FROM AROUND 572DM ON FRIDAY AFTERNOON TO
AROUND 550-552DM BY SATURDAY AFTERNOON...WITH 850MB TEMPERATURES
FALLING FROM AROUND 19C TO 7C DURING THE SAME PERIOD. ALTHOUGH THERE
WILL LIKELY NOT BE A WHOLE LOT OF MOISTURE ASSOCIATED WITH THIS
SYSTEM...WITH PWATS ONLY BRIEFLY RISING INTO THE 0.75-0.85 INCH
RANGE...THE IMPRESSIVE DYNAMICS AND COOLING THAT THIS SYSTEM WILL
POSSESS WILL LIKELY PRODUCE AT LEAST SOME SHOWER ACTIVITY DURING THE
DAY ON SATURDAY ACROSS SOUTH-CENTRAL AZ ALONG AND JUST AHEAD OF THE
MAIN FRONT. HOWEVER...THE BIGGEST IMPACT FROM THIS SYSTEM WILL
LIKELY BE THE WINDS...WITH WIDESPREAD ADVISORY-LEVEL WINDS POSSIBLE
ON SATURDAY AS EFFICIENT MIXING WILL LIKELY ALLOW 35-40KT 700MB
WINDS TO BE BROUGHT ALL THE WAY DOWN TO THE SFC...WITH BLOWING DUST
LIKELY TO BE A PROBLEM AS WELL. AFTER ANOTHER DAY OF 90+ DEGREE
TEMPERATURES ON FRIDAY...IT NOW LOOK LIKELY THAT HIGHS WILL REMAIN
WELL DOWN IN THE 70S ON SATURDAY. SUNDAY LOOKS LIKE IT WILL BE A
MUCH QUIETER DAY AS THE SYSTEM MOVES OFF RAPIDLY TO THE EAST...WITH
HIGHS REBOUNDING INTO THE LOW 80S ACROSS THE LOWER DESERTS UNDER
MOSTLY CLEAR SKIES...WITH JUST SOME AFTERNOON WESTERLY BREEZES.

MONDAY THROUGH WEDNESDAY...
ALTHOUGH THERE ARE DIFFERENCES BETWEEN THE MODELS...WITH THE EURO
BEING THE SLOWEST/COOLEST AND THE GEM BEING THE
FASTEST/WARMEST...THEY ALL ARE ATTEMPTING TO REBUILD RIDGING BACK
NORTHWARD OVER THE REGION FOR THE EARLY AND MIDDLE PART OF NEXT
WEEK...WITH TEMPERATURES WARMING BACK UP WELL INTO THE 90S UNDER
MOSTLY CLEAR SKIES. HOWEVER...WIDESPREAD TRIPLE-DIGIT TEMPERATURES
DO NOT APPEAR LIKELY AT THIS TIME...SINCE LONG-WAVE TROUGHING OVER
THE CENTRAL CONUS SHOULD KEEP OUR UPPER-LEVEL FLOW A NORTHWESTERLY
ONE.

&&

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

LIGHTER WINDS EXPECTED OVERNIGHT FOR THE TERMINALS WITH SPEEDS
STAYING MOSTLY UNDER 8KTS...WITH W/SW HEADINGS FOR THE PHX AREA
AIRFIELDS AND W/NW FOR KIPL AND KBLH. WINDS OVERNIGHT AND CLOSER
TOWARDS SUNRISE MAY BECOME LIGHT ENOUGH TO WARRANT VRB HEADINGS. THE
USUAL EASTERLY DRIFT SHOULD WORK IN FOR THE PHX AREA TERMINALS NEAR
OR AFTER 24/0800Z. SKIES WILL REMAIN MOSTLY CLEAR...SAVE FOR A FEW
HIGH CLOUDS MOVING FROM NW TO SE ACROSS ARIZONA OVERNIGHT.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
UPPER LOW WILL APPROACH THE AREA FRIDAY AND MOVE THROUGH THE AREA ON
SATURDAY. WINDS WILL ONCE AGAIN BE GUSTY ACROSS THE ENTIRE REGION ON
SATURDAY...HOWEVER MOISTURE WILL BE ON THE INCREASE AND TEMPERATURES
WILL BE SUBSTANTIALLY COOLER THAN NORMAL...THUS CRITICAL THRESHOLDS
SHOULD NOT BE REALIZED. MUCH LIGHTER WINDS ARE EXPECTED FROM SUNDAY
ONWARD ALTHOUGH TEMPERATURES WILL SLOWLY RECOVER BACK TOWARD NORMAL
VALUES. RECOVERIES WILL GRADUALLY DETERIORATE AS THE WEEK
PROGRESSES.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING
     AZZ020-025.

CA...FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING
     CAZ031.

$$

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

DISCUSSION...NOLTE
PREVIOUS DISCUSSION...HIRSCH/PERCHA
AVIATION....NOLTE
FIRE WEATHER...LEINS









000
FXUS65 KPSR 240355
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
855 PM MST WED APR 23 2014

.SYNOPSIS...
WARMER TEMPERATURES WILL MAKE A RETURN THURSDAY AND FRIDAY.
ANOTHER...MUCH STRONGER LOW PRESSURE SYSTEM WILL THEN AFFECT THE
REGION FROM FRIDAY ONWARD INTO THE UPCOMING WEEKEND. BREEZY TO WINDY
CONDITIONS CAN BE EXPECTED ALONG WITH MUCH COOLER TEMPERATURES ON
SATURDAY. THERE IS ALSO A CHANCE OF SHOWERS LATE FRIDAY NIGHT INTO
SATURDAY NIGHT...MAINLY FOR THE HIGHER TERRAIN OF SOUTH-CENTRAL
ARIZONA. HIGH PRESSURE BUILDING BACK NORTHWARD OVER THE WESTERN US
IS THEN EXPECTED TO BRING WARMER TEMPERATURES FOR THE EARLY AND
MIDDLE PARTS OF NEXT WEEK.

&&

.DISCUSSION...
COOLER BUT CONTINUED BREEZY CONDITIONS LINGERED TODAY IN THE WAKE OF
THE PASSING SHORTWAVE IMPULSE...WHICH HAS NOW CLEAR THE FOUR CORNER
AND CLEARING THE ROCKIES FRONT RANGE THIS EVENING. WHILE SURFACE
CONDITIONS IN TERMS OF DEWPOINTS HAVE DRIED SUBSTANTIALLY
TODAY...WITH SINGLE DIGITS TO LOW 10S OBSERVATIONS...WATER VAPOR
IMAGERY AND UPSTREAM RAOBS SHOW SOME HIGH LEVEL MOISTURE STREAMING
THROUGH THE SUBTLE RIDGE HEIGHTS TO OUR WEST. PATCHES OF HIGH CLOUDS
WILL CONTINUE TO STREAM FROM NORTHWEST TO SOUTHEAST TONIGHT...AT
MOST GENERATING BRIEF PERIODS OF PARTLY CLOUDY SKIES. SURFACE TEMPS
RUNNING 7 TO 10 DEGREES COOLER THAN THIS TIME TUESDAY EVENING...SO
EVEN WITH THE QUICK-PASSING CLOUDS...THINK MIN T FORECAST FOR
TONIGHT IS IN GOOD SHAPE. NO MAJOR UPDATES NEEDED...REMAINDER
OF THE DISCUSSION STILL APPLIES.

&&

.PREVIOUS DISCUSSION /ISSUED AT 255 PM MST/PDT/...
SHORT-WAVE RIDGE WILL BUILD IN OVERNIGHT...RESULTING IN MOSTLY CLEAR
SKIES AND LIGHT WINDS. THIS WILL PROMOTE EFFICIENT RADIATIONAL
COOLING AND TEMPERATURES NEAR OR EVEN SLIGHTLY BELOW NORMAL.

REBOUND IN TEMPERATURES IS EXPECTED THURSDAY AS A SHORT-WAVE RIDGE
IN THE SUBTROPICAL EASTERN PACIFIC BUILDS EASTWARD. ATTENTION WILL
THEN TURN TO A DEEPENING LOW PRESSURE SYSTEM ALONG THE WEST COAST
FRIDAY. BIGGEST IMPACT ACROSS THE FORECAST AREA WILL BE AN INCREASE
IN WIND AHEAD OF THIS SYSTEM. WINDS WILL BE STRONGEST ACROSS SE CA
WHERE GUSTS TO 35 MPH WILL BE POSSIBLE AND UP TO 30 MPH ACROSS
SOUTH-CENTRAL AZ INCLUDING THE PHOENIX METRO AREA.

PREVIOUS DISCUSSION /ISSUED AT 225 AM MST/PDT/...
THE MODELS ARE ALL NOW SHOWING VERY SHARP HEIGHT FALLS AND
TEMPERATURE DROPS AS THIS SYSTEM MOVES THROUGH...WITH 500MB HEIGHTS
OVER THE PHX AREA FALLING FROM AROUND 572DM ON FRIDAY AFTERNOON TO
AROUND 550-552DM BY SATURDAY AFTERNOON...WITH 850MB TEMPERATURES
FALLING FROM AROUND 19C TO 7C DURING THE SAME PERIOD. ALTHOUGH THERE
WILL LIKELY NOT BE A WHOLE LOT OF MOISTURE ASSOCIATED WITH THIS
SYSTEM...WITH PWATS ONLY BRIEFLY RISING INTO THE 0.75-0.85 INCH
RANGE...THE IMPRESSIVE DYNAMICS AND COOLING THAT THIS SYSTEM WILL
POSSESS WILL LIKELY PRODUCE AT LEAST SOME SHOWER ACTIVITY DURING THE
DAY ON SATURDAY ACROSS SOUTH-CENTRAL AZ ALONG AND JUST AHEAD OF THE
MAIN FRONT. HOWEVER...THE BIGGEST IMPACT FROM THIS SYSTEM WILL
LIKELY BE THE WINDS...WITH WIDESPREAD ADVISORY-LEVEL WINDS POSSIBLE
ON SATURDAY AS EFFICIENT MIXING WILL LIKELY ALLOW 35-40KT 700MB
WINDS TO BE BROUGHT ALL THE WAY DOWN TO THE SFC...WITH BLOWING DUST
LIKELY TO BE A PROBLEM AS WELL. AFTER ANOTHER DAY OF 90+ DEGREE
TEMPERATURES ON FRIDAY...IT NOW LOOK LIKELY THAT HIGHS WILL REMAIN
WELL DOWN IN THE 70S ON SATURDAY. SUNDAY LOOKS LIKE IT WILL BE A
MUCH QUIETER DAY AS THE SYSTEM MOVES OFF RAPIDLY TO THE EAST...WITH
HIGHS REBOUNDING INTO THE LOW 80S ACROSS THE LOWER DESERTS UNDER
MOSTLY CLEAR SKIES...WITH JUST SOME AFTERNOON WESTERLY BREEZES.

MONDAY THROUGH WEDNESDAY...
ALTHOUGH THERE ARE DIFFERENCES BETWEEN THE MODELS...WITH THE EURO
BEING THE SLOWEST/COOLEST AND THE GEM BEING THE
FASTEST/WARMEST...THEY ALL ARE ATTEMPTING TO REBUILD RIDGING BACK
NORTHWARD OVER THE REGION FOR THE EARLY AND MIDDLE PART OF NEXT
WEEK...WITH TEMPERATURES WARMING BACK UP WELL INTO THE 90S UNDER
MOSTLY CLEAR SKIES. HOWEVER...WIDESPREAD TRIPLE-DIGIT TEMPERATURES
DO NOT APPEAR LIKELY AT THIS TIME...SINCE LONG-WAVE TROUGHING OVER
THE CENTRAL CONUS SHOULD KEEP OUR UPPER-LEVEL FLOW A NORTHWESTERLY
ONE.

&&

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

LIGHTER WINDS EXPECTED OVERNIGHT FOR THE TERMINALS WITH SPEEDS
STAYING MOSTLY UNDER 8KTS...WITH W/SW HEADINGS FOR THE PHX AREA
AIRFIELDS AND W/NW FOR KIPL AND KBLH. WINDS OVERNIGHT AND CLOSER
TOWARDS SUNRISE MAY BECOME LIGHT ENOUGH TO WARRANT VRB HEADINGS. THE
USUAL EASTERLY DRIFT SHOULD WORK IN FOR THE PHX AREA TERMINALS NEAR
OR AFTER 24/0800Z. SKIES WILL REMAIN MOSTLY CLEAR...SAVE FOR A FEW
HIGH CLOUDS MOVING FROM NW TO SE ACROSS ARIZONA OVERNIGHT.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
UPPER LOW WILL APPROACH THE AREA FRIDAY AND MOVE THROUGH THE AREA ON
SATURDAY. WINDS WILL ONCE AGAIN BE GUSTY ACROSS THE ENTIRE REGION ON
SATURDAY...HOWEVER MOISTURE WILL BE ON THE INCREASE AND TEMPERATURES
WILL BE SUBSTANTIALLY COOLER THAN NORMAL...THUS CRITICAL THRESHOLDS
SHOULD NOT BE REALIZED. MUCH LIGHTER WINDS ARE EXPECTED FROM SUNDAY
ONWARD ALTHOUGH TEMPERATURES WILL SLOWLY RECOVER BACK TOWARD NORMAL
VALUES. RECOVERIES WILL GRADUALLY DETERIORATE AS THE WEEK
PROGRESSES.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING
     AZZ020-025.

CA...FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING
     CAZ031.

$$

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

DISCUSSION...NOLTE
PREVIOUS DISCUSSION...HIRSCH/PERCHA
AVIATION....NOLTE
FIRE WEATHER...LEINS










000
FXUS65 KPSR 232157
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
255 PM MST WED APR 23 2014

.SYNOPSIS...
WARMER TEMPERATURES WILL MAKE A RETURN THURSDAY AND FRIDAY.
ANOTHER...MUCH STRONGER LOW PRESSURE SYSTEM WILL THEN AFFECT THE
REGION FROM FRIDAY ONWARD INTO THE UPCOMING WEEKEND. BREEZY TO WINDY
CONDITIONS CAN BE EXPECTED ALONG WITH MUCH COOLER TEMPERATURES ON
SATURDAY. THERE IS ALSO A CHANCE OF SHOWERS LATE FRIDAY NIGHT INTO
SATURDAY NIGHT...MAINLY FOR THE HIGHER TERRAIN OF SOUTH-CENTRAL
ARIZONA. HIGH PRESSURE BUILDING BACK NORTHWARD OVER THE WESTERN US
IS THEN EXPECTED TO BRING WARMER TEMPERATURES FOR THE EARLY AND
MIDDLE PARTS OF NEXT WEEK.

&&

.DISCUSSION...
SHORT-WAVE TROUGH NEAR THE FOUR CORNERS CONTINUES TO SLIDE EASTWARD.
BEHIND THE TROUGH AXIS...NORTHWESTERLY FLOW HAS ADVECTED COOLER AND
DRIER AIR INTO THE REGION...WITH TEMPERATURES RUNNING NEARLY 10
DEGREES BELOW THOSE OBSERVED YESTERDAY. SHORT-WAVE RIDGE WILL BUILD
IN OVERNIGHT...RESULTING IN MOSTLY CLEAR SKIES AND LIGHT WINDS. THIS
WILL PROMOTE EFFICIENT RADIATIONAL COOLING AND TEMPERATURES NEAR OR
EVEN SLIGHTLY BELOW NORMAL.

REBOUND IN TEMPERATURES IS EXPECTED THURSDAY AS A SHORT-WAVE RIDGE
IN THE SUBTROPICAL EASTERN PACIFIC BUILDS EASTWARD. ATTENTION WILL
THEN TURN TO A DEEPENING LOW PRESSURE SYSTEM ALONG THE WEST COAST
FRIDAY. BIGGEST IMPACT ACROSS THE FORECAST AREA WILL BE AN INCREASE
IN WIND AHEAD OF THIS SYSTEM. WINDS WILL BE STRONGEST ACROSS SE CA
WHERE GUSTS TO 35 MPH WILL BE POSSIBLE AND UP TO 30 MPH ACROSS
SOUTH-CENTRAL AZ INCLUDING THE PHOENIX METRO AREA.

&&

.PREVIOUS DISCUSSION...
THE MODELS ARE ALL NOW SHOWING VERY SHARP HEIGHT FALLS AND
TEMPERATURE DROPS AS THIS SYSTEM MOVES THROUGH...WITH 500MB HEIGHTS
OVER THE PHX AREA FALLING FROM AROUND 572DM ON FRIDAY AFTERNOON TO
AROUND 550-552DM BY SATURDAY AFTERNOON...WITH 850MB TEMPERATURES
FALLING FROM AROUND 19C TO 7C DURING THE SAME PERIOD. ALTHOUGH THERE
WILL LIKELY NOT BE A WHOLE LOT OF MOISTURE ASSOCIATED WITH THIS
SYSTEM...WITH PWATS ONLY BRIEFLY RISING INTO THE 0.75-0.85 INCH
RANGE...THE IMPRESSIVE DYNAMICS AND COOLING THAT THIS SYSTEM WILL
POSSESS WILL LIKELY PRODUCE AT LEAST SOME SHOWER ACTIVITY DURING THE
DAY ON SATURDAY ACROSS SOUTH-CENTRAL AZ ALONG AND JUST AHEAD OF THE
MAIN FRONT. HOWEVER...THE BIGGEST IMPACT FROM THIS SYSTEM WILL
LIKELY BE THE WINDS...WITH WIDESPREAD ADVISORY-LEVEL WINDS POSSIBLE
ON SATURDAY AS EFFICIENT MIXING WILL LIKELY ALLOW 35-40KT 700MB
WINDS TO BE BROUGHT ALL THE WAY DOWN TO THE SFC...WITH BLOWING DUST
LIKELY TO BE A PROBLEM AS WELL. AFTER ANOTHER DAY OF 90+ DEGREE
TEMPERATURES ON FRIDAY...IT NOW LOOK LIKELY THAT HIGHS WILL REMAIN
WELL DOWN IN THE 70S ON SATURDAY. SUNDAY LOOKS LIKE IT WILL BE A
MUCH QUIETER DAY AS THE SYSTEM MOVES OFF RAPIDLY TO THE EAST...WITH
HIGHS REBOUNDING INTO THE LOW 80S ACROSS THE LOWER DESERTS UNDER
MOSTLY CLEAR SKIES...WITH JUST SOME AFTERNOON WESTERLY BREEZES.

MONDAY THROUGH WEDNESDAY...
ALTHOUGH THERE ARE DIFFERENCES BETWEEN THE MODELS...WITH THE EURO
BEING THE SLOWEST/COOLEST AND THE GEM BEING THE
FASTEST/WARMEST...THEY ALL ARE ATTEMPTING TO REBUILD RIDGING BACK
NORTHWARD OVER THE REGION FOR THE EARLY AND MIDDLE PART OF NEXT
WEEK...WITH TEMPERATURES WARMING BACK UP WELL INTO THE 90S UNDER
MOSTLY CLEAR SKIES. HOWEVER...WIDESPREAD TRIPLE-DIGIT TEMPERATURES
DO NOT APPEAR LIKELY AT THIS TIME...SINCE LONG-WAVE TROUGHING OVER
THE CENTRAL CONUS SHOULD KEEP OUR UPPER-LEVEL FLOW A NORTHWESTERLY
ONE.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
WEST WINDS AROUND 12G20KTS WILL PREVAIL AT ALL PHOENIX SITES THROUGH
LATE AFTERNOON BUT SHOULD RELAX QUICKLY AFTER SUNSET. FROM
THERE...EXPECT THE USUAL EASTERLY DRIFT TO KICK IN AROUND MIDNIGHT
WITH LIGHT SPEEDS THROUGH AT LEAST 18Z THURSDAY.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
NORTHWEST GUSTY WINDS WILL GRADUALLY BACK TO THE WEST LATER THIS
AFTERNOON AND RELAX AFTER 03Z WITH THE LOSS OF DAYTIME HEATING.
ASIDE FROM A FEW HIGH CLOUDS SKIES SHOULD BE CLEAR. NO AVIATION
CONCERNS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
UPPER LOW WILL APPROACH THE AREA FRIDAY AND MOVE THROUGH THE AREA ON
SATURDAY. WINDS WILL ONCE AGAIN BE GUSTY ACROSS THE ENTIRE REGION ON
SATURDAY...HOWEVER MOISTURE WILL BE ON THE INCREASE AND TEMPERATURES
WILL BE SUBSTANTIALLY COOLER THAN NORMAL...THUS CRITICAL THRESHOLDS
SHOULD NOT BE REALIZED. MUCH LIGHTER WINDS ARE EXPECTED FROM SUNDAY
ONWARD ALTHOUGH TEMPERATURES WILL SLOWLY RECOVER BACK TOWARD NORMAL
VALUES. RECOVERIES WILL GRADUALLY DETERIORATE AS THE WEEK
PROGRESSES.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING
     AZZ020-025.

CA...FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING
     CAZ031.

$$

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

DISCUSSION...HIRSCH
PREVIOUS DISCUSSION...PERCHA
AVIATION....LEINS
FIRE WEATHER...LEINS






000
FXUS65 KPSR 232157
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
255 PM MST WED APR 23 2014

.SYNOPSIS...
WARMER TEMPERATURES WILL MAKE A RETURN THURSDAY AND FRIDAY.
ANOTHER...MUCH STRONGER LOW PRESSURE SYSTEM WILL THEN AFFECT THE
REGION FROM FRIDAY ONWARD INTO THE UPCOMING WEEKEND. BREEZY TO WINDY
CONDITIONS CAN BE EXPECTED ALONG WITH MUCH COOLER TEMPERATURES ON
SATURDAY. THERE IS ALSO A CHANCE OF SHOWERS LATE FRIDAY NIGHT INTO
SATURDAY NIGHT...MAINLY FOR THE HIGHER TERRAIN OF SOUTH-CENTRAL
ARIZONA. HIGH PRESSURE BUILDING BACK NORTHWARD OVER THE WESTERN US
IS THEN EXPECTED TO BRING WARMER TEMPERATURES FOR THE EARLY AND
MIDDLE PARTS OF NEXT WEEK.

&&

.DISCUSSION...
SHORT-WAVE TROUGH NEAR THE FOUR CORNERS CONTINUES TO SLIDE EASTWARD.
BEHIND THE TROUGH AXIS...NORTHWESTERLY FLOW HAS ADVECTED COOLER AND
DRIER AIR INTO THE REGION...WITH TEMPERATURES RUNNING NEARLY 10
DEGREES BELOW THOSE OBSERVED YESTERDAY. SHORT-WAVE RIDGE WILL BUILD
IN OVERNIGHT...RESULTING IN MOSTLY CLEAR SKIES AND LIGHT WINDS. THIS
WILL PROMOTE EFFICIENT RADIATIONAL COOLING AND TEMPERATURES NEAR OR
EVEN SLIGHTLY BELOW NORMAL.

REBOUND IN TEMPERATURES IS EXPECTED THURSDAY AS A SHORT-WAVE RIDGE
IN THE SUBTROPICAL EASTERN PACIFIC BUILDS EASTWARD. ATTENTION WILL
THEN TURN TO A DEEPENING LOW PRESSURE SYSTEM ALONG THE WEST COAST
FRIDAY. BIGGEST IMPACT ACROSS THE FORECAST AREA WILL BE AN INCREASE
IN WIND AHEAD OF THIS SYSTEM. WINDS WILL BE STRONGEST ACROSS SE CA
WHERE GUSTS TO 35 MPH WILL BE POSSIBLE AND UP TO 30 MPH ACROSS
SOUTH-CENTRAL AZ INCLUDING THE PHOENIX METRO AREA.

&&

.PREVIOUS DISCUSSION...
THE MODELS ARE ALL NOW SHOWING VERY SHARP HEIGHT FALLS AND
TEMPERATURE DROPS AS THIS SYSTEM MOVES THROUGH...WITH 500MB HEIGHTS
OVER THE PHX AREA FALLING FROM AROUND 572DM ON FRIDAY AFTERNOON TO
AROUND 550-552DM BY SATURDAY AFTERNOON...WITH 850MB TEMPERATURES
FALLING FROM AROUND 19C TO 7C DURING THE SAME PERIOD. ALTHOUGH THERE
WILL LIKELY NOT BE A WHOLE LOT OF MOISTURE ASSOCIATED WITH THIS
SYSTEM...WITH PWATS ONLY BRIEFLY RISING INTO THE 0.75-0.85 INCH
RANGE...THE IMPRESSIVE DYNAMICS AND COOLING THAT THIS SYSTEM WILL
POSSESS WILL LIKELY PRODUCE AT LEAST SOME SHOWER ACTIVITY DURING THE
DAY ON SATURDAY ACROSS SOUTH-CENTRAL AZ ALONG AND JUST AHEAD OF THE
MAIN FRONT. HOWEVER...THE BIGGEST IMPACT FROM THIS SYSTEM WILL
LIKELY BE THE WINDS...WITH WIDESPREAD ADVISORY-LEVEL WINDS POSSIBLE
ON SATURDAY AS EFFICIENT MIXING WILL LIKELY ALLOW 35-40KT 700MB
WINDS TO BE BROUGHT ALL THE WAY DOWN TO THE SFC...WITH BLOWING DUST
LIKELY TO BE A PROBLEM AS WELL. AFTER ANOTHER DAY OF 90+ DEGREE
TEMPERATURES ON FRIDAY...IT NOW LOOK LIKELY THAT HIGHS WILL REMAIN
WELL DOWN IN THE 70S ON SATURDAY. SUNDAY LOOKS LIKE IT WILL BE A
MUCH QUIETER DAY AS THE SYSTEM MOVES OFF RAPIDLY TO THE EAST...WITH
HIGHS REBOUNDING INTO THE LOW 80S ACROSS THE LOWER DESERTS UNDER
MOSTLY CLEAR SKIES...WITH JUST SOME AFTERNOON WESTERLY BREEZES.

MONDAY THROUGH WEDNESDAY...
ALTHOUGH THERE ARE DIFFERENCES BETWEEN THE MODELS...WITH THE EURO
BEING THE SLOWEST/COOLEST AND THE GEM BEING THE
FASTEST/WARMEST...THEY ALL ARE ATTEMPTING TO REBUILD RIDGING BACK
NORTHWARD OVER THE REGION FOR THE EARLY AND MIDDLE PART OF NEXT
WEEK...WITH TEMPERATURES WARMING BACK UP WELL INTO THE 90S UNDER
MOSTLY CLEAR SKIES. HOWEVER...WIDESPREAD TRIPLE-DIGIT TEMPERATURES
DO NOT APPEAR LIKELY AT THIS TIME...SINCE LONG-WAVE TROUGHING OVER
THE CENTRAL CONUS SHOULD KEEP OUR UPPER-LEVEL FLOW A NORTHWESTERLY
ONE.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
WEST WINDS AROUND 12G20KTS WILL PREVAIL AT ALL PHOENIX SITES THROUGH
LATE AFTERNOON BUT SHOULD RELAX QUICKLY AFTER SUNSET. FROM
THERE...EXPECT THE USUAL EASTERLY DRIFT TO KICK IN AROUND MIDNIGHT
WITH LIGHT SPEEDS THROUGH AT LEAST 18Z THURSDAY.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
NORTHWEST GUSTY WINDS WILL GRADUALLY BACK TO THE WEST LATER THIS
AFTERNOON AND RELAX AFTER 03Z WITH THE LOSS OF DAYTIME HEATING.
ASIDE FROM A FEW HIGH CLOUDS SKIES SHOULD BE CLEAR. NO AVIATION
CONCERNS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
UPPER LOW WILL APPROACH THE AREA FRIDAY AND MOVE THROUGH THE AREA ON
SATURDAY. WINDS WILL ONCE AGAIN BE GUSTY ACROSS THE ENTIRE REGION ON
SATURDAY...HOWEVER MOISTURE WILL BE ON THE INCREASE AND TEMPERATURES
WILL BE SUBSTANTIALLY COOLER THAN NORMAL...THUS CRITICAL THRESHOLDS
SHOULD NOT BE REALIZED. MUCH LIGHTER WINDS ARE EXPECTED FROM SUNDAY
ONWARD ALTHOUGH TEMPERATURES WILL SLOWLY RECOVER BACK TOWARD NORMAL
VALUES. RECOVERIES WILL GRADUALLY DETERIORATE AS THE WEEK
PROGRESSES.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING
     AZZ020-025.

CA...FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING
     CAZ031.

$$

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

DISCUSSION...HIRSCH
PREVIOUS DISCUSSION...PERCHA
AVIATION....LEINS
FIRE WEATHER...LEINS







000
FXUS65 KPSR 231617
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
915 AM MST WED APR 23 2014

.SYNOPSIS...
THE WEATHER DISTURBANCE THAT BROUGHT GUSTY WINDS AND AREAS OF
BLOWING DUST TO THE REGION ON TUESDAY IS EXPECTED TO BRING COOLER
TEMPERATURES TODAY AS IT MOVES OFF TO THE EAST. WARMER TEMPERATURES
WILL MAKE A RETURN THURSDAY AND FRIDAY. ANOTHER...MUCH STRONGER LOW
PRESSURE SYSTEM WILL THEN AFFECT THE REGION FROM FRIDAY ONWARD INTO
THE UPCOMING WEEKEND. BREEZY TO WINDY CONDITIONS CAN BE EXPECTED
ALONG WITH MUCH COOLER TEMPERATURES ON SATURDAY. THERE IS ALSO A
CHANCE OF SHOWERS LATE FRIDAY NIGHT INTO SATURDAY NIGHT...MAINLY FOR
THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA. HIGH PRESSURE BUILDING
BACK NORTHWARD OVER THE WESTERN US IS THEN EXPECTED TO BRING WARMER
TEMPERATURES FOR THE EARLY AND MIDDLE PARTS OF NEXT WEEK.

&&

.DISCUSSION...
ANOTHER MORE COMPACT SHORT-WAVE TROUGH IS EVIDENT IN WV IMAGERY
ACROSS NW AZ. THIS SYSTEM WILL MOVE RAPIDLY EASTWARD...BRINGING A
REINFORCING SHOT OF DRIER AIR TO THE REGION TODAY. OBSERVATIONS
INDICATE THAT SURFACE DEWPOINTS ARE ALREADY AS LOW AS THE TEENS IN
THE PHOENIX METRO AREA. STILL EXPECTING COOLER TEMPERATURES
TODAY...AS MUCH AS 10 DEGREES LOWER THAN THOSE OBSERVED YESTERDAY.
FORECAST REMAINS ON TRACK AND ONLY MINOR ADJUSTMENTS TO THE
SHORT-TERM TEMPERATURES ARE ANTICIPATED.

&&


.PREVIOUS DISCUSSION...
WEDNESDAY AND THURSDAY...
THE DRY COOL FRONT THAT BROUGHT OUR CWA GUSTY WINDS...PATCHY BLOWING
DUST...AND HIGH FIRE DANGER ON TUESDAY HAS FINALLY PUSHED INTO
SOUTHEASTERN AZ THIS MORNING. THE MAIN IMPACTS FROM THIS FRONT TODAY
WILL BE SOMEWHAT COOLER TEMPERATURES AND LOWER DEWPOINTS...ALONG
WITH SOME GUSTY AFTERNOON BREEZES ACROSS SOUTHWEST AND SOUTH-CENTRAL
AZ. CURRENT FORECAST SOUNDINGS FOR THE PHX AREA ARE INDICATING THAT
850MB TEMPS WILL DROP FROM YESTERDAY`S 22C TO AROUND 17C BY THIS
AFTERNOON...WHICH SHOULD RESULT IN ABOUT 8-10 DEGREES OF COOLING AT
THE SFC...WITH HIGHS REMAINING MOSTLY IN THE MID TO UPPER 80S
TODAY...WHICH IS NOW RIGHT AROUND NORMAL FOR THIS TIME OF YEAR.
NIGHTTIME LOWS TONIGHT SHOULD ALSO BE NOTICEABLY COOLER...WITH MOST
OUTLYING LOWER DESERT LOCATIONS SEEING LOWS IN THE 50S UNDER MOSTLY
CLEAR SKIES. WEAK RIDGING AHEAD OF THE NEXT UPPER TROF IS THEN
EXPECTED TO BRING SOMEWHAT WARMER TEMPERATURES ON THURSDAY...WITH
LOWER DESERT HIGHS PUSHING BACK INTO THE LOW TO MID 90S.

FRIDAY THROUGH SUNDAY...
THE NEXT PACIFIC SYSTEM THAT WILL BE AFFECTING OUR AREA FROM FRIDAY
ONWARD INTO THE WEEKEND CAN ALREADY BE SEEN ON LATEST IR SATELLITE
IMAGERY JUST BEGINNING TO MOVE SOUTHWARD FROM THE GULF OF ALASKA
INTO THE EASTERN PACIFIC. THE LATEST GFS...EURO...AND GEM HAVE NOW
COME INTO VERY GOOD AGREEMENT THAT THIS NEXT SYSTEM WILL BE THE
STRONGEST SYSTEM THAT WE HAVE SEEN FOR A WHILE. THEY ALL NOW MOVE A
RATHER ROBUST...AND COLD UPPER LOW INLAND OVER CENTRAL AND SOUTHERN
CA BY LATE FRIDAY EVENING AND EARLY SATURDAY...THEN ACROSS NORTHERN
ARIZONA DURING THE DAY ON SATURDAY...AND INTO NEW MEXICO BY SUNDAY
MORNING.

THE MODELS ARE ALL NOW SHOWING VERY SHARP HEIGHT FALLS AND
TEMPERATURE DROPS AS THIS SYSTEM MOVES THROUGH...WITH 500MB HEIGHTS
OVER THE PHX AREA FALLING FROM AROUND 572DM ON FRIDAY AFTERNOON TO
AROUND 550-552DM BY SATURDAY AFTERNOON...WITH 850MB TEMPERATURES
FALLING FROM AROUND 19C TO 7C DURING THE SAME PERIOD. ALTHOUGH THERE
WILL LIKELY NOT BE A WHOLE LOT OF MOISTURE ASSOCIATED WITH THIS
SYSTEM...WITH PWATS ONLY BRIEFLY RISING INTO THE 0.75-0.85 INCH
RANGE...THE IMPRESSIVE DYNAMICS AND COOLING THAT THIS SYSTEM WILL
POSSESS WILL LIKELY PRODUCE AT LEAST SOME SHOWER ACTIVITY DURING THE
DAY ON SATURDAY ACROSS SOUTH-CENTRAL AZ ALONG AND JUST AHEAD OF THE
MAIN FRONT. HOWEVER...THE BIGGEST IMPACT FROM THIS SYSTEM WILL
LIKELY BE THE WINDS...WITH WIDESPREAD ADVISORY-LEVEL WINDS POSSIBLE
ON SATURDAY AS EFFICIENT MIXING WILL LIKELY ALLOW 35-40KT 700MB
WINDS TO BE BROUGHT ALL THE WAY DOWN TO THE SFC...WITH BLOWING DUST
LIKELY TO BE A PROBLEM AS WELL. AFTER ANOTHER DAY OF 90+ DEGREE
TEMPERATURES ON FRIDAY...IT NOW LOOK LIKELY THAT HIGHS WILL REMAIN
WELL DOWN IN THE 70S ON SATURDAY. SUNDAY LOOKS LIKE IT WILL BE A
MUCH QUIETER DAY AS THE SYSTEM MOVES OFF RAPIDLY TO THE EAST...WITH
HIGHS REBOUNDING INTO THE LOW 80S ACROSS THE LOWER DESERTS UNDER
MOSTLY CLEAR SKIES...WITH JUST SOME AFTERNOON WESTERLY BREEZES.

MONDAY THROUGH WEDNESDAY...
ALTHOUGH THERE ARE DIFFERENCES BETWEEN THE MODELS...WITH THE EURO
BEING THE SLOWEST/COOLEST AND THE GEM BEING THE
FASTEST/WARMEST...THEY ALL ARE ATTEMPTING TO REBUILD RIDGING BACK
NORTHWARD OVER THE REGION FOR THE EARLY AND MIDDLE PART OF NEXT
WEEK...WITH TEMPERATURES WARMING BACK UP WELL INTO THE 90S UNDER
MOSTLY CLEAR SKIES. HOWEVER...WIDESPREAD TRIPLE-DIGIT TEMPERATURES
DO NOT APPEAR LIKELY AT THIS TIME...SINCE LONG-WAVE TROUGHING OVER
THE CENTRAL CONUS SHOULD KEEP OUR UPPER-LEVEL FLOW A NORTHWESTERLY
ONE.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
NO SIGNIFICANT AVIATION CONCERNS THROUGH THURSDAY MORNING...WITH
TIMING OF WIND SHIFTS THE PRIMARY FORECAST CHALLENGE. WITH FAIRLY
GOOD CONFIDENCE...A PERIOD OF VARIABLE SFC WINDS WILL PREVAIL THIS
MORNING DESPITE A PERSISTENT WEST 5-10KT WINDS 2K-4K ABOVE THE
GROUND. EVENTUALLY LATE THIS MORNING...WLY WINDS WILL MIX TO THE
GROUND. THERE MAY BE A PERIOD OF A FEW HIGHER GUSTS UP TO
20KT...THOUGH THESE CONDITIONS SHOULD BE MORE TEMPORALLY LIMITED.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
SFC WINDS WILL EVENTUALLY VEER TO A MORE NLY DIRECTION THIS
MORNING...AND CONFIDENCE IS FAIRLY GOOD THAT A FEW HIGHER GUSTS WILL
MATERIALIZE BY LATE MORNING (PARTICULARLY AT KBLH). NO OTHER
AVIATION CONCERNS AS THE PRESSURE GRADIENT WEAKENS BY LATE
AFTERNOON...AND SFC WINDS FALL BACK TO AROUND 5KT AND BECOME MORE
WLY IN DIRECTION WITH NOCTURNAL DECOUPLING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
A VERY STRONG UPPER LEVEL LOW WILL APPROACH THE AREA ON FRIDAY AND
MOVE THROUGH THE DISTRICTS ON SATURDAY. AHEAD OF THIS WEATHER
SYSTEM...WINDS WILL INCREASE AND BECOME FREQUENTLY GUSTY FRIDAY
AFTERNOON AND EVENING. THE STRONGEST WINDS FRIDAY WILL BE
EXPERIENCED ACROSS SE CALIFORNIA AND THE LOWER COLORADO RIVER
VALLEY...AND ITS POSSIBLE CRITICAL THRESHOLDS MAY BE MET.
TEMPERATURES ON SATURDAY WILL PLUMMET TO WELL BELOW NORMAL
LEVELS...AND HUMIDITY LEVELS WILL INCREASE (ALONG WITH A POSSIBILITY
OF LIGHT RAIN). THIS MAY OTHERWISE LIMIT A MUCH HIGHER FIRE
DANGER...BECAUSE WINDS SATURDAY ACROSS THE ENTIRE REGION WILL BE
UNUSUALLY STRONG FOR MUCH OF THE DAY (LIKELY GUSTING AOA 40 MPH).
COOLER WEATHER WILL LINGER SUNDAY WITH A WARMING TREND EARLY NEXT
WEEK. AS TEMPERATURES RECOVER NEXT WEEK...AFTERNOON HUMIDITIES WILL
ONCE AGAIN DROP INTO THE SINGLE DIGITS WITH ONLY FAIR OVERNIGHT
RECOVERY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...HIRSCH
PREVIOUS DISCUSSION...PERCHA
AVIATION....MO
FIRE WEATHER...LEINS/MO











000
FXUS65 KPSR 231136
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
435 AM MST WED APR 23 2014

...UPDATED AVIATION AND FIRE WEATHER...

.SYNOPSIS...
THE WEATHER DISTURBANCE THAT BROUGHT GUSTY WINDS AND AREAS OF
BLOWING DUST TO THE REGION ON TUESDAY IS EXPECTED TO BRING COOLER
TEMPERATURES TODAY AS IT MOVES OFF TO THE EAST. WARMER TEMPERATURES
WILL MAKE A RETURN THURSDAY AND FRIDAY. ANOTHER...MUCH STRONGER LOW
PRESSURE SYSTEM WILL THEN AFFECT THE REGION FROM FRIDAY ONWARD INTO
THE UPCOMING WEEKEND. BREEZY TO WINDY CONDITIONS CAN BE EXPECTED
ALONG WITH MUCH COOLER TEMPERATURES ON SATURDAY. THERE IS ALSO A
CHANCE OF SHOWERS LATE FRIDAY NIGHT INTO SATURDAY NIGHT...MAINLY FOR
THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA. HIGH PRESSURE BUILDING
BACK NORTHWARD OVER THE WESTERN US IS THEN EXPECTED TO BRING WARMER
TEMPERATURES FOR THE EARLY AND MIDDLE PARTS OF NEXT WEEK.

&&

.DISCUSSION...
WEDNESDAY AND THURSDAY...
THE DRY COOL FRONT THAT BROUGHT OUR CWA GUSTY WINDS...PATCHY BLOWING
DUST...AND HIGH FIRE DANGER ON TUESDAY HAS FINALLY PUSHED INTO
SOUTHEASTERN AZ THIS MORNING. THE MAIN IMPACTS FROM THIS FRONT TODAY
WILL BE SOMEWHAT COOLER TEMPERATURES AND LOWER DEWPOINTS...ALONG
WITH SOME GUSTY AFTERNOON BREEZES ACROSS SOUTHWEST AND SOUTH-CENTRAL
AZ. CURRENT FORECAST SOUNDINGS FOR THE PHX AREA ARE INDICATING THAT
850MB TEMPS WILL DROP FROM YESTERDAY`S 22C TO AROUND 17C BY THIS
AFTERNOON...WHICH SHOULD RESULT IN ABOUT 8-10 DEGREES OF COOLING AT
THE SFC...WITH HIGHS REMAINING MOSTLY IN THE MID TO UPPER 80S
TODAY...WHICH IS NOW RIGHT AROUND NORMAL FOR THIS TIME OF YEAR.
NIGHTTIME LOWS TONIGHT SHOULD ALSO BE NOTICEABLY COOLER...WITH MOST
OUTLYING LOWER DESERT LOCATIONS SEEING LOWS IN THE 50S UNDER MOSTLY
CLEAR SKIES. WEAK RIDGING AHEAD OF THE NEXT UPPER TROF IS THEN
EXPECTED TO BRING SOMEWHAT WARMER TEMPERATURES ON THURSDAY...WITH
LOWER DESERT HIGHS PUSHING BACK INTO THE LOW TO MID 90S.

FRIDAY THROUGH SUNDAY...
THE NEXT PACIFIC SYSTEM THAT WILL BE AFFECTING OUR AREA FROM FRIDAY
ONWARD INTO THE WEEKEND CAN ALREADY BE SEEN ON LATEST IR SATELLITE
IMAGERY JUST BEGINNING TO MOVE SOUTHWARD FROM THE GULF OF ALASKA
INTO THE EASTERN PACIFIC. THE LATEST GFS...EURO...AND GEM HAVE NOW
COME INTO VERY GOOD AGREEMENT THAT THIS NEXT SYSTEM WILL BE THE
STRONGEST SYSTEM THAT WE HAVE SEEN FOR A WHILE. THEY ALL NOW MOVE A
RATHER ROBUST...AND COLD UPPER LOW INLAND OVER CENTRAL AND SOUTHERN
CA BY LATE FRIDAY EVENING AND EARLY SATURDAY...THEN ACROSS NORTHERN
ARIZONA DURING THE DAY ON SATURDAY...AND INTO NEW MEXICO BY SUNDAY
MORNING.

THE MODELS ARE ALL NOW SHOWING VERY SHARP HEIGHT FALLS AND
TEMPERATURE DROPS AS THIS SYSTEM MOVES THROUGH...WITH 500MB HEIGHTS
OVER THE PHX AREA FALLING FROM AROUND 572DM ON FRIDAY AFTERNOON TO
AROUND 550-552DM BY SATURDAY AFTERNOON...WITH 850MB TEMPERATURES
FALLING FROM AROUND 19C TO 7C DURING THE SAME PERIOD. ALTHOUGH THERE
WILL LIKELY NOT BE A WHOLE LOT OF MOISTURE ASSOCIATED WITH THIS
SYSTEM...WITH PWATS ONLY BRIEFLY RISING INTO THE 0.75-0.85 INCH
RANGE...THE IMPRESSIVE DYNAMICS AND COOLING THAT THIS SYSTEM WILL
POSSESS WILL LIKELY PRODUCE AT LEAST SOME SHOWER ACTIVITY DURING THE
DAY ON SATURDAY ACROSS SOUTH-CENTRAL AZ ALONG AND JUST AHEAD OF THE
MAIN FRONT. HOWEVER...THE BIGGEST IMPACT FROM THIS SYSTEM WILL
LIKELY BE THE WINDS...WITH WIDESPREAD ADVISORY-LEVEL WINDS POSSIBLE
ON SATURDAY AS EFFICIENT MIXING WILL LIKELY ALLOW 35-40KT 700MB
WINDS TO BE BROUGHT ALL THE WAY DOWN TO THE SFC...WITH BLOWING DUST
LIKELY TO BE A PROBLEM AS WELL. AFTER ANOTHER DAY OF 90+ DEGREE
TEMPERATURES ON FRIDAY...IT NOW LOOK LIKELY THAT HIGHS WILL REMAIN
WELL DOWN IN THE 70S ON SATURDAY. SUNDAY LOOKS LIKE IT WILL BE A
MUCH QUIETER DAY AS THE SYSTEM MOVES OFF RAPIDLY TO THE EAST...WITH
HIGHS REBOUNDING INTO THE LOW 80S ACROSS THE LOWER DESERTS UNDER
MOSTLY CLEAR SKIES...WITH JUST SOME AFTERNOON WESTERLY BREEZES.

MONDAY THROUGH WEDNESDAY...
ALTHOUGH THERE ARE DIFFERENCES BETWEEN THE MODELS...WITH THE EURO
BEING THE SLOWEST/COOLEST AND THE GEM BEING THE
FASTEST/WARMEST...THEY ALL ARE ATTEMPTING TO REBUILD RIDGING BACK
NORTHWARD OVER THE REGION FOR THE EARLY AND MIDDLE PART OF NEXT
WEEK...WITH TEMPERATURES WARMING BACK UP WELL INTO THE 90S UNDER
MOSTLY CLEAR SKIES. HOWEVER...WIDESPREAD TRIPLE-DIGIT TEMPERATURES
DO NOT APPEAR LIKELY AT THIS TIME...SINCE LONG-WAVE TROUGHING OVER
THE CENTRAL CONUS SHOULD KEEP OUR UPPER-LEVEL FLOW A NORTHWESTERLY
ONE.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
NO SIGNIFICANT AVIATION CONCERNS THROUGH THURSDAY MORNING...WITH
TIMING OF WIND SHIFTS THE PRIMARY FORECAST CHALLENGE. WITH FAIRLY
GOOD CONFIDENCE...A PERIOD OF VARIABLE SFC WINDS WILL PREVAIL THIS
MORNING DESPITE A PERSISTENT WEST 5-10KT WINDS 2K-4K ABOVE THE
GROUND. EVENTUALLY LATE THIS MORNING...WLY WINDS WILL MIX TO THE
GROUND. THERE MAY BE A PERIOD OF A FEW HIGHER GUSTS UP TO
20KT...THOUGH THESE CONDITIONS SHOULD BE MORE TEMPORALLY LIMITED.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
SFC WINDS WILL EVENTUALLY VEER TO A MORE NLY DIRECTION THIS
MORNING...AND CONFIDENCE IS FAIRLY GOOD THAT A FEW HIGHER GUSTS WILL
MATERIALIZE BY LATE MORNING (PARTICULARLY AT KBLH). NO OTHER
AVIATION CONCERNS AS THE PRESSURE GRADIENT WEAKENS BY LATE
AFTERNOON...AND SFC WINDS FALL BACK TO AROUND 5KT AND BECOME MORE
WLY IN DIRECTION WITH NOCTURNAL DECOUPLING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
A VERY STRONG UPPER LEVEL LOW WILL APPROACH THE AREA ON FRIDAY AND
MOVE THROUGH THE DISTRICTS ON SATURDAY. AHEAD OF THIS WEATHER
SYSTEM...WINDS WILL INCREASE AND BECOME FREQUENTLY GUSTY FRIDAY
AFTERNOON AND EVENING. THE STRONGEST WINDS FRIDAY WILL BE
EXPERIENCED ACROSS SE CALIFORNIA AND THE LOWER COLORADO RIVER
VALLEY...AND ITS POSSIBLE CRITICAL THRESHOLDS MAY BE MET.
TEMPERATURES ON SATURDAY WILL PLUMMET TO WELL BELOW NORMAL
LEVELS...AND HUMIDITY LEVELS WILL INCREASE (ALONG WITH A POSSIBILITY
OF LIGHT RAIN). THIS MAY OTHERWISE LIMIT A MUCH HIGHER FIRE
DANGER...BECAUSE WINDS SATURDAY ACROSS THE ENTIRE REGION WILL BE
UNUSUALLY STRONG FOR MUCH OF THE DAY (LIKELY GUSTING AOA 40 MPH).
COOLER WEATHER WILL LINGER SUNDAY WITH A WARMING TREND EARLY NEXT
WEEK. AS TEMPERATURES RECOVER NEXT WEEK...AFTERNOON HUMIDITIES WILL
ONCE AGAIN DROP INTO THE SINGLE DIGITS WITH ONLY FAIR OVERNIGHT
RECOVERY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

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








000
FXUS65 KPSR 231136
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
435 AM MST WED APR 23 2014

...UPDATED AVIATION AND FIRE WEATHER...

.SYNOPSIS...
THE WEATHER DISTURBANCE THAT BROUGHT GUSTY WINDS AND AREAS OF
BLOWING DUST TO THE REGION ON TUESDAY IS EXPECTED TO BRING COOLER
TEMPERATURES TODAY AS IT MOVES OFF TO THE EAST. WARMER TEMPERATURES
WILL MAKE A RETURN THURSDAY AND FRIDAY. ANOTHER...MUCH STRONGER LOW
PRESSURE SYSTEM WILL THEN AFFECT THE REGION FROM FRIDAY ONWARD INTO
THE UPCOMING WEEKEND. BREEZY TO WINDY CONDITIONS CAN BE EXPECTED
ALONG WITH MUCH COOLER TEMPERATURES ON SATURDAY. THERE IS ALSO A
CHANCE OF SHOWERS LATE FRIDAY NIGHT INTO SATURDAY NIGHT...MAINLY FOR
THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA. HIGH PRESSURE BUILDING
BACK NORTHWARD OVER THE WESTERN US IS THEN EXPECTED TO BRING WARMER
TEMPERATURES FOR THE EARLY AND MIDDLE PARTS OF NEXT WEEK.

&&

.DISCUSSION...
WEDNESDAY AND THURSDAY...
THE DRY COOL FRONT THAT BROUGHT OUR CWA GUSTY WINDS...PATCHY BLOWING
DUST...AND HIGH FIRE DANGER ON TUESDAY HAS FINALLY PUSHED INTO
SOUTHEASTERN AZ THIS MORNING. THE MAIN IMPACTS FROM THIS FRONT TODAY
WILL BE SOMEWHAT COOLER TEMPERATURES AND LOWER DEWPOINTS...ALONG
WITH SOME GUSTY AFTERNOON BREEZES ACROSS SOUTHWEST AND SOUTH-CENTRAL
AZ. CURRENT FORECAST SOUNDINGS FOR THE PHX AREA ARE INDICATING THAT
850MB TEMPS WILL DROP FROM YESTERDAY`S 22C TO AROUND 17C BY THIS
AFTERNOON...WHICH SHOULD RESULT IN ABOUT 8-10 DEGREES OF COOLING AT
THE SFC...WITH HIGHS REMAINING MOSTLY IN THE MID TO UPPER 80S
TODAY...WHICH IS NOW RIGHT AROUND NORMAL FOR THIS TIME OF YEAR.
NIGHTTIME LOWS TONIGHT SHOULD ALSO BE NOTICEABLY COOLER...WITH MOST
OUTLYING LOWER DESERT LOCATIONS SEEING LOWS IN THE 50S UNDER MOSTLY
CLEAR SKIES. WEAK RIDGING AHEAD OF THE NEXT UPPER TROF IS THEN
EXPECTED TO BRING SOMEWHAT WARMER TEMPERATURES ON THURSDAY...WITH
LOWER DESERT HIGHS PUSHING BACK INTO THE LOW TO MID 90S.

FRIDAY THROUGH SUNDAY...
THE NEXT PACIFIC SYSTEM THAT WILL BE AFFECTING OUR AREA FROM FRIDAY
ONWARD INTO THE WEEKEND CAN ALREADY BE SEEN ON LATEST IR SATELLITE
IMAGERY JUST BEGINNING TO MOVE SOUTHWARD FROM THE GULF OF ALASKA
INTO THE EASTERN PACIFIC. THE LATEST GFS...EURO...AND GEM HAVE NOW
COME INTO VERY GOOD AGREEMENT THAT THIS NEXT SYSTEM WILL BE THE
STRONGEST SYSTEM THAT WE HAVE SEEN FOR A WHILE. THEY ALL NOW MOVE A
RATHER ROBUST...AND COLD UPPER LOW INLAND OVER CENTRAL AND SOUTHERN
CA BY LATE FRIDAY EVENING AND EARLY SATURDAY...THEN ACROSS NORTHERN
ARIZONA DURING THE DAY ON SATURDAY...AND INTO NEW MEXICO BY SUNDAY
MORNING.

THE MODELS ARE ALL NOW SHOWING VERY SHARP HEIGHT FALLS AND
TEMPERATURE DROPS AS THIS SYSTEM MOVES THROUGH...WITH 500MB HEIGHTS
OVER THE PHX AREA FALLING FROM AROUND 572DM ON FRIDAY AFTERNOON TO
AROUND 550-552DM BY SATURDAY AFTERNOON...WITH 850MB TEMPERATURES
FALLING FROM AROUND 19C TO 7C DURING THE SAME PERIOD. ALTHOUGH THERE
WILL LIKELY NOT BE A WHOLE LOT OF MOISTURE ASSOCIATED WITH THIS
SYSTEM...WITH PWATS ONLY BRIEFLY RISING INTO THE 0.75-0.85 INCH
RANGE...THE IMPRESSIVE DYNAMICS AND COOLING THAT THIS SYSTEM WILL
POSSESS WILL LIKELY PRODUCE AT LEAST SOME SHOWER ACTIVITY DURING THE
DAY ON SATURDAY ACROSS SOUTH-CENTRAL AZ ALONG AND JUST AHEAD OF THE
MAIN FRONT. HOWEVER...THE BIGGEST IMPACT FROM THIS SYSTEM WILL
LIKELY BE THE WINDS...WITH WIDESPREAD ADVISORY-LEVEL WINDS POSSIBLE
ON SATURDAY AS EFFICIENT MIXING WILL LIKELY ALLOW 35-40KT 700MB
WINDS TO BE BROUGHT ALL THE WAY DOWN TO THE SFC...WITH BLOWING DUST
LIKELY TO BE A PROBLEM AS WELL. AFTER ANOTHER DAY OF 90+ DEGREE
TEMPERATURES ON FRIDAY...IT NOW LOOK LIKELY THAT HIGHS WILL REMAIN
WELL DOWN IN THE 70S ON SATURDAY. SUNDAY LOOKS LIKE IT WILL BE A
MUCH QUIETER DAY AS THE SYSTEM MOVES OFF RAPIDLY TO THE EAST...WITH
HIGHS REBOUNDING INTO THE LOW 80S ACROSS THE LOWER DESERTS UNDER
MOSTLY CLEAR SKIES...WITH JUST SOME AFTERNOON WESTERLY BREEZES.

MONDAY THROUGH WEDNESDAY...
ALTHOUGH THERE ARE DIFFERENCES BETWEEN THE MODELS...WITH THE EURO
BEING THE SLOWEST/COOLEST AND THE GEM BEING THE
FASTEST/WARMEST...THEY ALL ARE ATTEMPTING TO REBUILD RIDGING BACK
NORTHWARD OVER THE REGION FOR THE EARLY AND MIDDLE PART OF NEXT
WEEK...WITH TEMPERATURES WARMING BACK UP WELL INTO THE 90S UNDER
MOSTLY CLEAR SKIES. HOWEVER...WIDESPREAD TRIPLE-DIGIT TEMPERATURES
DO NOT APPEAR LIKELY AT THIS TIME...SINCE LONG-WAVE TROUGHING OVER
THE CENTRAL CONUS SHOULD KEEP OUR UPPER-LEVEL FLOW A NORTHWESTERLY
ONE.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
NO SIGNIFICANT AVIATION CONCERNS THROUGH THURSDAY MORNING...WITH
TIMING OF WIND SHIFTS THE PRIMARY FORECAST CHALLENGE. WITH FAIRLY
GOOD CONFIDENCE...A PERIOD OF VARIABLE SFC WINDS WILL PREVAIL THIS
MORNING DESPITE A PERSISTENT WEST 5-10KT WINDS 2K-4K ABOVE THE
GROUND. EVENTUALLY LATE THIS MORNING...WLY WINDS WILL MIX TO THE
GROUND. THERE MAY BE A PERIOD OF A FEW HIGHER GUSTS UP TO
20KT...THOUGH THESE CONDITIONS SHOULD BE MORE TEMPORALLY LIMITED.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
SFC WINDS WILL EVENTUALLY VEER TO A MORE NLY DIRECTION THIS
MORNING...AND CONFIDENCE IS FAIRLY GOOD THAT A FEW HIGHER GUSTS WILL
MATERIALIZE BY LATE MORNING (PARTICULARLY AT KBLH). NO OTHER
AVIATION CONCERNS AS THE PRESSURE GRADIENT WEAKENS BY LATE
AFTERNOON...AND SFC WINDS FALL BACK TO AROUND 5KT AND BECOME MORE
WLY IN DIRECTION WITH NOCTURNAL DECOUPLING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
A VERY STRONG UPPER LEVEL LOW WILL APPROACH THE AREA ON FRIDAY AND
MOVE THROUGH THE DISTRICTS ON SATURDAY. AHEAD OF THIS WEATHER
SYSTEM...WINDS WILL INCREASE AND BECOME FREQUENTLY GUSTY FRIDAY
AFTERNOON AND EVENING. THE STRONGEST WINDS FRIDAY WILL BE
EXPERIENCED ACROSS SE CALIFORNIA AND THE LOWER COLORADO RIVER
VALLEY...AND ITS POSSIBLE CRITICAL THRESHOLDS MAY BE MET.
TEMPERATURES ON SATURDAY WILL PLUMMET TO WELL BELOW NORMAL
LEVELS...AND HUMIDITY LEVELS WILL INCREASE (ALONG WITH A POSSIBILITY
OF LIGHT RAIN). THIS MAY OTHERWISE LIMIT A MUCH HIGHER FIRE
DANGER...BECAUSE WINDS SATURDAY ACROSS THE ENTIRE REGION WILL BE
UNUSUALLY STRONG FOR MUCH OF THE DAY (LIKELY GUSTING AOA 40 MPH).
COOLER WEATHER WILL LINGER SUNDAY WITH A WARMING TREND EARLY NEXT
WEEK. AS TEMPERATURES RECOVER NEXT WEEK...AFTERNOON HUMIDITIES WILL
ONCE AGAIN DROP INTO THE SINGLE DIGITS WITH ONLY FAIR OVERNIGHT
RECOVERY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

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







000
FXUS65 KPSR 230924
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
225 AM MST WED APR 23 2014

.SYNOPSIS...
THE WEATHER DISTURBANCE THAT BROUGHT GUSTY WINDS AND AREAS OF
BLOWING DUST TO THE REGION ON TUESDAY IS EXPECTED TO BRING COOLER
TEMPERATURES TODAY AS IT MOVES OFF TO THE EAST. WARMER TEMPERATURES
WILL MAKE A RETURN THURSDAY AND FRIDAY. ANOTHER...MUCH STRONGER LOW
PRESSURE SYSTEM WILL THEN AFFECT THE REGION FROM FRIDAY ONWARD INTO
THE UPCOMING WEEKEND. BREEZY TO WINDY CONDITIONS CAN BE EXPECTED
ALONG WITH MUCH COOLER TEMPERATURES ON SATURDAY. THERE IS ALSO A
CHANCE OF SHOWERS LATE FRIDAY NIGHT INTO SATURDAY NIGHT...MAINLY FOR
THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA. HIGH PRESSURE BUILDING
BACK NORTHWARD OVER THE WESTERN US IS THEN EXPECTED TO BRING WARMER
TEMPERATURES FOR THE EARLY AND MIDDLE PARTS OF NEXT WEEK.

&&

.DISCUSSION...
WEDNESDAY AND THURSDAY...
THE DRY COOL FRONT THAT BROUGHT OUR CWA GUSTY WINDS...PATCHY BLOWING
DUST...AND HIGH FIRE DANGER ON TUESDAY HAS FINALLY PUSHED INTO
SOUTHEASTERN AZ THIS MORNING. THE MAIN IMPACTS FROM THIS FRONT TODAY
WILL BE SOMEWHAT COOLER TEMPERATURES AND LOWER DEWPOINTS...ALONG
WITH SOME GUSTY AFTERNOON BREEZES ACROSS SOUTHWEST AND SOUTH-CENTRAL
AZ. CURRENT FORECAST SOUNDINGS FOR THE PHX AREA ARE INDICATING THAT
850MB TEMPS WILL DROP FROM YESTERDAY`S 22C TO AROUND 17C BY THIS
AFTERNOON...WHICH SHOULD RESULT IN ABOUT 8-10 DEGREES OF COOLING AT
THE SFC...WITH HIGHS REMAINING MOSTLY IN THE MID TO UPPER 80S
TODAY...WHICH IS NOW RIGHT AROUND NORMAL FOR THIS TIME OF YEAR.
NIGHTTIME LOWS TONIGHT SHOULD ALSO BE NOTICEABLY COOLER...WITH MOST
OUTLYING LOWER DESERT LOCATIONS SEEING LOWS IN THE 50S UNDER MOSTLY
CLEAR SKIES. WEAK RIDGING AHEAD OF THE NEXT UPPER TROF IS THEN
EXPECTED TO BRING SOMEWHAT WARMER TEMPERATURES ON THURSDAY...WITH
LOWER DESERT HIGHS PUSHING BACK INTO THE LOW TO MID 90S.

FRIDAY THROUGH SUNDAY...
THE NEXT PACIFIC SYSTEM THAT WILL BE AFFECTING OUR AREA FROM FRIDAY
ONWARD INTO THE WEEKEND CAN ALREADY BE SEEN ON LATEST IR SATELLITE
IMAGERY JUST BEGINNING TO MOVE SOUTHWARD FROM THE GULF OF ALASKA
INTO THE EASTERN PACIFIC. THE LATEST GFS...EURO...AND GEM HAVE NOW
COME INTO VERY GOOD AGREEMENT THAT THIS NEXT SYSTEM WILL BE THE
STRONGEST SYSTEM THAT WE HAVE SEEN FOR A WHILE. THEY ALL NOW MOVE A
RATHER ROBUST...AND COLD UPPER LOW INLAND OVER CENTRAL AND SOUTHERN
CA BY LATE FRIDAY EVENING AND EARLY SATURDAY...THEN ACROSS NORTHERN
ARIZONA DURING THE DAY ON SATURDAY...AND INTO NEW MEXICO BY SUNDAY
MORNING.

THE MODELS ARE ALL NOW SHOWING VERY SHARP HEIGHT FALLS AND
TEMPERATURE DROPS AS THIS SYSTEM MOVES THROUGH...WITH 500MB HEIGHTS
OVER THE PHX AREA FALLING FROM AROUND 572DM ON FRIDAY AFTERNOON TO
AROUND 550-552DM BY SATURDAY AFTERNOON...WITH 850MB TEMPERATURES
FALLING FROM AROUND 19C TO 7C DURING THE SAME PERIOD. ALTHOUGH THERE
WILL LIKELY NOT BE A WHOLE LOT OF MOISTURE ASSOCIATED WITH THIS
SYSTEM...WITH PWATS ONLY BRIEFLY RISING INTO THE 0.75-0.85 INCH
RANGE...THE IMPRESSIVE DYNAMICS AND COOLING THAT THIS SYSTEM WILL
POSSESS WILL LIKELY PRODUCE AT LEAST SOME SHOWER ACTIVITY DURING THE
DAY ON SATURDAY ACROSS SOUTH-CENTRAL AZ ALONG AND JUST AHEAD OF THE
MAIN FRONT. HOWEVER...THE BIGGEST IMPACT FROM THIS SYSTEM WILL
LIKELY BE THE WINDS...WITH WIDESPREAD ADVISORY-LEVEL WINDS POSSIBLE
ON SATURDAY AS EFFICIENT MIXING WILL LIKELY ALLOW 35-40KT 700MB
WINDS TO BE BROUGHT ALL THE WAY DOWN TO THE SFC...WITH BLOWING DUST
LIKELY TO BE A PROBLEM AS WELL. AFTER ANOTHER DAY OF 90+ DEGREE
TEMPERATURES ON FRIDAY...IT NOW LOOK LIKELY THAT HIGHS WILL REMAIN
WELL DOWN IN THE 70S ON SATURDAY. SUNDAY LOOKS LIKE IT WILL BE A
MUCH QUIETER DAY AS THE SYSTEM MOVES OFF RAPIDLY TO THE EAST...WITH
HIGHS REBOUNDING INTO THE LOW 80S ACROSS THE LOWER DESERTS UNDER
MOSTLY CLEAR SKIES...WITH JUST SOME AFTERNOON WESTERLY BREEZES.

MONDAY THROUGH WEDNESDAY...
ALTHOUGH THERE ARE DIFFERENCES BETWEEN THE MODELS...WITH THE EURO
BEING THE SLOWEST/COOLEST AND THE GEM BEING THE
FASTEST/WARMEST...THEY ALL ARE ATTEMPTING TO REBUILD RIDGING BACK
NORTHWARD OVER THE REGION FOR THE EARLY AND MIDDLE PART OF NEXT
WEEK...WITH TEMPERATURES WARMING BACK UP WELL INTO THE 90S UNDER
MOSTLY CLEAR SKIES. HOWEVER...WIDESPREAD TRIPLE-DIGIT TEMPERATURES
DO NOT APPEAR LIKELY AT THIS TIME...SINCE LONG-WAVE TROUGHING OVER
THE CENTRAL CONUS SHOULD KEEP OUR UPPER-LEVEL FLOW A NORTHWESTERLY
ONE.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
WEST/SOUTHWESTERLY WINDS WILL REMAIN ELEVATED THROUGH MUCH OF THE
OVERNIGHT HOURS AS A DRY SURFACE COOL FRONT PASSES THROUGH CENTRAL
ARIZONA. NEAR 23/09-10Z...LIGHT SPEEDS UNDER 6KTS WITH VRB HEADINGS
POSSIBLE BEFORE TURNING WESTERLY AGAIN AS EARLY AS MIDDAY. HIGH
CLOUDS ALONG THE FRONTAL BOUNDARY WILL QUICKLY CLEAR TO THE
EAST...LEAVING MOSTLY CLEAR SKIES FOR THE TERMINALS BY SUNRISE.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
ELEVATED WEST WINDS TO PERSIST OVERNIGHT FOR KIPL AND KBLH...WITH
ISOLATED GUSTS IN THE 20KT RANGE STILL POSSIBLE THROUGH MIDNIGHT
LOCAL. SUSTAINED SPEEDS TO HOLD 10-15KTS GNLY THROUGH SUNRISE BEFORE
DROPPING 8KTS OR LESS FOR WEDNESDAY MORNING. IN THE WAKE OF A DRY
COOL FRONT PASSAGE...SKIES WILL REMAIN MOSTLY CLEAR THROUGH WEDNESDAY
MORNING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
STRONG UPPER LEVEL LOW WILL APPROACH THE AREA ON FRIDAY AND MOVE
THROUGH ARIZONA/CALIFORNIA ON SATURDAY. AHEAD OF THE TROUGH...WINDS
WILL INCREASE QUITE A BIT FRIDAY AFTERNOON AND ITS POSSIBLE CRITICAL
THRESHOLDS COULD BE REALIZED IN SOME PARTS OF THE FORECAST AREA.
STILL NEED A LITTLE BETTER CONSISTENCY IN THE MODELS BEFORE GOING
WITH A FIRE WX WATCH AND WILL HOLD OFF AT THIS POINT. TEMPERATURES
ON SATURDAY AND SUNDAY /POST-TROUGH/ WILL BE SUBSTANTIALLY COOLER
AND HUMIDITIES WILL RECOVER QUITE A BIT...THUS FIRE WEATHER CONCERNS
WILL BE MUCH LESS. TEMPS WILL RECOVER NEXT WEEK AND CONSEQUENTLY
AFTERNOON HUMIDITIES WILL ONCE AGAIN DROP INTO THE SINGLE DIGITS.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

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






000
FXUS65 KPSR 230924
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
225 AM MST WED APR 23 2014

.SYNOPSIS...
THE WEATHER DISTURBANCE THAT BROUGHT GUSTY WINDS AND AREAS OF
BLOWING DUST TO THE REGION ON TUESDAY IS EXPECTED TO BRING COOLER
TEMPERATURES TODAY AS IT MOVES OFF TO THE EAST. WARMER TEMPERATURES
WILL MAKE A RETURN THURSDAY AND FRIDAY. ANOTHER...MUCH STRONGER LOW
PRESSURE SYSTEM WILL THEN AFFECT THE REGION FROM FRIDAY ONWARD INTO
THE UPCOMING WEEKEND. BREEZY TO WINDY CONDITIONS CAN BE EXPECTED
ALONG WITH MUCH COOLER TEMPERATURES ON SATURDAY. THERE IS ALSO A
CHANCE OF SHOWERS LATE FRIDAY NIGHT INTO SATURDAY NIGHT...MAINLY FOR
THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA. HIGH PRESSURE BUILDING
BACK NORTHWARD OVER THE WESTERN US IS THEN EXPECTED TO BRING WARMER
TEMPERATURES FOR THE EARLY AND MIDDLE PARTS OF NEXT WEEK.

&&

.DISCUSSION...
WEDNESDAY AND THURSDAY...
THE DRY COOL FRONT THAT BROUGHT OUR CWA GUSTY WINDS...PATCHY BLOWING
DUST...AND HIGH FIRE DANGER ON TUESDAY HAS FINALLY PUSHED INTO
SOUTHEASTERN AZ THIS MORNING. THE MAIN IMPACTS FROM THIS FRONT TODAY
WILL BE SOMEWHAT COOLER TEMPERATURES AND LOWER DEWPOINTS...ALONG
WITH SOME GUSTY AFTERNOON BREEZES ACROSS SOUTHWEST AND SOUTH-CENTRAL
AZ. CURRENT FORECAST SOUNDINGS FOR THE PHX AREA ARE INDICATING THAT
850MB TEMPS WILL DROP FROM YESTERDAY`S 22C TO AROUND 17C BY THIS
AFTERNOON...WHICH SHOULD RESULT IN ABOUT 8-10 DEGREES OF COOLING AT
THE SFC...WITH HIGHS REMAINING MOSTLY IN THE MID TO UPPER 80S
TODAY...WHICH IS NOW RIGHT AROUND NORMAL FOR THIS TIME OF YEAR.
NIGHTTIME LOWS TONIGHT SHOULD ALSO BE NOTICEABLY COOLER...WITH MOST
OUTLYING LOWER DESERT LOCATIONS SEEING LOWS IN THE 50S UNDER MOSTLY
CLEAR SKIES. WEAK RIDGING AHEAD OF THE NEXT UPPER TROF IS THEN
EXPECTED TO BRING SOMEWHAT WARMER TEMPERATURES ON THURSDAY...WITH
LOWER DESERT HIGHS PUSHING BACK INTO THE LOW TO MID 90S.

FRIDAY THROUGH SUNDAY...
THE NEXT PACIFIC SYSTEM THAT WILL BE AFFECTING OUR AREA FROM FRIDAY
ONWARD INTO THE WEEKEND CAN ALREADY BE SEEN ON LATEST IR SATELLITE
IMAGERY JUST BEGINNING TO MOVE SOUTHWARD FROM THE GULF OF ALASKA
INTO THE EASTERN PACIFIC. THE LATEST GFS...EURO...AND GEM HAVE NOW
COME INTO VERY GOOD AGREEMENT THAT THIS NEXT SYSTEM WILL BE THE
STRONGEST SYSTEM THAT WE HAVE SEEN FOR A WHILE. THEY ALL NOW MOVE A
RATHER ROBUST...AND COLD UPPER LOW INLAND OVER CENTRAL AND SOUTHERN
CA BY LATE FRIDAY EVENING AND EARLY SATURDAY...THEN ACROSS NORTHERN
ARIZONA DURING THE DAY ON SATURDAY...AND INTO NEW MEXICO BY SUNDAY
MORNING.

THE MODELS ARE ALL NOW SHOWING VERY SHARP HEIGHT FALLS AND
TEMPERATURE DROPS AS THIS SYSTEM MOVES THROUGH...WITH 500MB HEIGHTS
OVER THE PHX AREA FALLING FROM AROUND 572DM ON FRIDAY AFTERNOON TO
AROUND 550-552DM BY SATURDAY AFTERNOON...WITH 850MB TEMPERATURES
FALLING FROM AROUND 19C TO 7C DURING THE SAME PERIOD. ALTHOUGH THERE
WILL LIKELY NOT BE A WHOLE LOT OF MOISTURE ASSOCIATED WITH THIS
SYSTEM...WITH PWATS ONLY BRIEFLY RISING INTO THE 0.75-0.85 INCH
RANGE...THE IMPRESSIVE DYNAMICS AND COOLING THAT THIS SYSTEM WILL
POSSESS WILL LIKELY PRODUCE AT LEAST SOME SHOWER ACTIVITY DURING THE
DAY ON SATURDAY ACROSS SOUTH-CENTRAL AZ ALONG AND JUST AHEAD OF THE
MAIN FRONT. HOWEVER...THE BIGGEST IMPACT FROM THIS SYSTEM WILL
LIKELY BE THE WINDS...WITH WIDESPREAD ADVISORY-LEVEL WINDS POSSIBLE
ON SATURDAY AS EFFICIENT MIXING WILL LIKELY ALLOW 35-40KT 700MB
WINDS TO BE BROUGHT ALL THE WAY DOWN TO THE SFC...WITH BLOWING DUST
LIKELY TO BE A PROBLEM AS WELL. AFTER ANOTHER DAY OF 90+ DEGREE
TEMPERATURES ON FRIDAY...IT NOW LOOK LIKELY THAT HIGHS WILL REMAIN
WELL DOWN IN THE 70S ON SATURDAY. SUNDAY LOOKS LIKE IT WILL BE A
MUCH QUIETER DAY AS THE SYSTEM MOVES OFF RAPIDLY TO THE EAST...WITH
HIGHS REBOUNDING INTO THE LOW 80S ACROSS THE LOWER DESERTS UNDER
MOSTLY CLEAR SKIES...WITH JUST SOME AFTERNOON WESTERLY BREEZES.

MONDAY THROUGH WEDNESDAY...
ALTHOUGH THERE ARE DIFFERENCES BETWEEN THE MODELS...WITH THE EURO
BEING THE SLOWEST/COOLEST AND THE GEM BEING THE
FASTEST/WARMEST...THEY ALL ARE ATTEMPTING TO REBUILD RIDGING BACK
NORTHWARD OVER THE REGION FOR THE EARLY AND MIDDLE PART OF NEXT
WEEK...WITH TEMPERATURES WARMING BACK UP WELL INTO THE 90S UNDER
MOSTLY CLEAR SKIES. HOWEVER...WIDESPREAD TRIPLE-DIGIT TEMPERATURES
DO NOT APPEAR LIKELY AT THIS TIME...SINCE LONG-WAVE TROUGHING OVER
THE CENTRAL CONUS SHOULD KEEP OUR UPPER-LEVEL FLOW A NORTHWESTERLY
ONE.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
WEST/SOUTHWESTERLY WINDS WILL REMAIN ELEVATED THROUGH MUCH OF THE
OVERNIGHT HOURS AS A DRY SURFACE COOL FRONT PASSES THROUGH CENTRAL
ARIZONA. NEAR 23/09-10Z...LIGHT SPEEDS UNDER 6KTS WITH VRB HEADINGS
POSSIBLE BEFORE TURNING WESTERLY AGAIN AS EARLY AS MIDDAY. HIGH
CLOUDS ALONG THE FRONTAL BOUNDARY WILL QUICKLY CLEAR TO THE
EAST...LEAVING MOSTLY CLEAR SKIES FOR THE TERMINALS BY SUNRISE.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
ELEVATED WEST WINDS TO PERSIST OVERNIGHT FOR KIPL AND KBLH...WITH
ISOLATED GUSTS IN THE 20KT RANGE STILL POSSIBLE THROUGH MIDNIGHT
LOCAL. SUSTAINED SPEEDS TO HOLD 10-15KTS GNLY THROUGH SUNRISE BEFORE
DROPPING 8KTS OR LESS FOR WEDNESDAY MORNING. IN THE WAKE OF A DRY
COOL FRONT PASSAGE...SKIES WILL REMAIN MOSTLY CLEAR THROUGH WEDNESDAY
MORNING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
STRONG UPPER LEVEL LOW WILL APPROACH THE AREA ON FRIDAY AND MOVE
THROUGH ARIZONA/CALIFORNIA ON SATURDAY. AHEAD OF THE TROUGH...WINDS
WILL INCREASE QUITE A BIT FRIDAY AFTERNOON AND ITS POSSIBLE CRITICAL
THRESHOLDS COULD BE REALIZED IN SOME PARTS OF THE FORECAST AREA.
STILL NEED A LITTLE BETTER CONSISTENCY IN THE MODELS BEFORE GOING
WITH A FIRE WX WATCH AND WILL HOLD OFF AT THIS POINT. TEMPERATURES
ON SATURDAY AND SUNDAY /POST-TROUGH/ WILL BE SUBSTANTIALLY COOLER
AND HUMIDITIES WILL RECOVER QUITE A BIT...THUS FIRE WEATHER CONCERNS
WILL BE MUCH LESS. TEMPS WILL RECOVER NEXT WEEK AND CONSEQUENTLY
AFTERNOON HUMIDITIES WILL ONCE AGAIN DROP INTO THE SINGLE DIGITS.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

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







000
FXUS65 KPSR 230443
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
943 PM MST TUE APR 22 2014

.SYNOPSIS...
BREEZY TO WINDY CONDITIONS WILL SLOWLY DECREASE TONIGHT AS A DRY
WEATHER SYSTEM PASSES ACROSS ARIZONA. ANTICIPATE COOLER HIGH
TEMPERATURES WEDNESDAY WITH READINGS CLOSE TO NORMAL. WARMER
TEMPERATURES WILL MAKE A RETURN THURSDAY AND FRIDAY. ANOTHER LOW
PRESSURE SYSTEM WILL AFFECT THE REGION FRIDAY AND SATURDAY. BREEZY
TO WINDY CONDITIONS CAN BE EXPECTED ALONG WITH MUCH COOLER
TEMPERATURES SATURDAY. THERE IS ALSO A SLIGHT CHANCE OF SHOWERS LATE
FRIDAY NIGHT INTO SATURDAY NIGHT...MAINLY FOR THE HIGHER TERRAIN OF
SOUTH-CENTRAL ARIZONA. ANTICIPATE A WARMING TREND MONDAY AND TUESDAY.

&&

.DISCUSSION...
WELL-DEFINED AND DEEP PACIFIC TROUGH AND SURFACE FRONTAL BOUNDARY
OBSERVED ON EVENING WV/IR IMAGERY AND MSLP ANALYSIS. HIGH CLOUDS
BISECT ARIZONA...WITH THE EASTERN HALF INCLUDING CENTRAL/EASTERN
MARICOPA COUNTY UNDER PARTLY TO MOSTLY CLOUDY SKIES...AND CLEAR SKIES
ACROSS WESTERN ARIZONA TOWARDS THE COLORADO RIVER VALLEY. ELEVATED
DAYTIME WINDS HAVE DIMINISHED THROUGH THE EARLY EVENING
HOURS...HOWEVER SOME ISOLATED STRONGER GUSTS OF 25 TO 30 MPH HAVE
BEEN REPORTED. WINDS WILL REMAIN BREEZY OVERNIGHT AND MAY SEE
ADDITIONAL GUSTS ACROSS CENTRAL ARIZONA AS THE FRONTAL BOUNDARY MOVES
THROUGH THE AREA...BUT GENERALLY FALL UNDER THE SPEEDS OBSERVED
EARLIER TODAY.

00Z NEIGHBOR RAOB DATA INDICATE THE COOL FRONTAL BOUNDARY HAD REACHED
KVEF...WHERE THE LOWER ATMO LAYERS THROUGH 700MB HAD COOLED ABOUT 8
DEGREES. KTUS HAD YET TO INDICATE THE SAME COOLING...WITH TEMPERATURE
PROFILE READINGS SIMILAR TO THOSE OBSERVED 24 HRS AGO. SFC
TEMPERATURES FOR WEDNESDAY EXPECTED COOLER THAN READINGS OBSERVED
THIS AFTERNOON IN LIGHT OF THIS COOLER AIRMASS MOVING THROUGH THE
STATE...FINALLY GIVING THE AREA AN AFTERNOON OF TEMPERATURES CLOSER
TO APRIL NORMALS. ALONG WITH THE COOLER TEMPERATURES...MUCH DRIER AIR
WILL FILTER INTO THE AREA...DROPPING DAYTIME DEWPOINTS INTO THE TEENS
BY THE AFTERNOON. RESULTING HUMIDITIES WILL FALL BELOW 10 PERCENT FOR
MANY LOCATIONS...BUT GENERALLY LIGHTER POST-FRONTAL
WINDS TOMORROW SHOULD KEEP WIDESPREAD CRITICAL FIRE WEATHER
CONDITIONS AT BAY.

FOR TONIGHT...CLOUDS AND THE SURFACE BOUNDARY WILL CONTINUE TO CLEAR
TO THE EAST WITH WINDS REMAINING BREEZY. MINOR ADJUSTMENTS WERE
NEEDED TO THE SKY COVER GRID TO CAPTURE THE THICKER CLOUDS CURRENTLY
OBSERVED AND THEIR EXIT OVER THE NEXT FEW HOURS. DEWPOINTS WERE ALSO
ADJUSTED TO MATCH CURRENT TRENDS AS UPSTREAM READINGS WERE ALREADY
BELOW EVEN THE RAW GRIDDED FORECAST GUIDANCE. REMAINDER OF THE
FORECAST DISCUSSION STILL APPLICABLE FOR WEDNESDAY AND BEYOND.

&&

.PREVIOUS DISCUSSION /ISSUED AT 325 AM MST/PDT/...
WEDNESDAY AND THURSDAY...
BEHIND THE FRONT ON WEDNESDAY LOOK FOR HIGHS IN THE UPPER 80S ACROSS
THE LOWER DESERTS. ANTICIPATE LESS WIND THOUGH A TRAILING SHORT WAVE
WILL MAINTAIN SOME BREEZINESS. A FLAT RIDGE PASSES BY THURSDAY WITH
HIGHS A FEW DEGREES WARMER.

FRIDAY THROUGH SUNDAY...
THE NEXT PACIFIC SYSTEM WILL AFFECT OUR FORECAST AREA FRIDAY AND
SATURDAY. THE GFS CONTINUES TO BE A BIT FASTER THAN THE ECWMF...WITH
THE GEM IN BETWEEN. IN SHORT...BREEZY TO WINDY CONDITIONS DEVELOP
FRIDAY AFTERNOON...WITH BREEZINESS CONTINUING FRIDAY NIGHT AND
SATURDAY. SPEEDS FRIDAY AFTERNOON ARE LOOKING QUITE SIMILAR TO
TODAY...TUESDAY. EVENING AND OVERNIGHT BREEZINESS WILL BE STRONGER
THOUGH. THUS ANTICIPATE RED FLAG POTENTIAL AND POSSIBLY WIND
ADVISORY CONDITIONS SIMILAR TO TODAY. THE NEXT SYSTEM WILL DIG
DEEPER AND BRING EVEN COOLER AIR. MADE SOME SLIGHT DOWNWARD
ADJUSTMENTS TO THE HIGHS FOR SATURDAY WITH LOWER DESERT HIGHS IN
UPPER 70S. ALSO INTRODUCED SOME SLIGHT CHANCE POPS IN PORTIONS OF
OUR FORECAST AREA FOR LATE FRIDAY NIGHT INTO SATURDAY NIGHT...MAINLY
THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA. ANTICIPATE SLIGHTLY
WARMER HIGHS SUNDAY WITH DRY NORTHWEST FLOW ALOFT.

MONDAY AND TUESDAY...
THE FLOW AMPLIFIES EARLY NEXT WEEK FOR RIDGING OVER THE WEST COAST
FOR A WARMING TREND. LINGERING TROUGHING OVER THE CENTRAL CONUS MAY
KEEP THE TEMPS FROM SHOOTING UP EXCESSIVELY...BUT STILL LOOK FOR
HIGHS GETTING INTO THE 90S BY TUESDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
WEST/SOUTHWESTERLY WINDS WILL REMAIN ELEVATED THROUGH MUCH OF THE
OVERNIGHT HOURS AS A DRY SURFACE COOL FRONT PASSES THROUGH CENTRAL
ARIZONA. NEAR 23/09-10Z...LIGHT SPEEDS UNDER 6KTS WITH VRB HEADINGS
POSSIBLE BEFORE TURNING WESTERLY AGAIN AS EARLY AS MIDDAY. HIGH
CLOUDS ALONG THE FRONTAL BOUNDARY WILL QUICKLY CLEAR TO THE
EAST...LEAVING MOSTLY CLEAR SKIES FOR THE TERMINALS BY SUNRISE.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
ELEVATED WEST WINDS TO PERSIST OVERNIGHT FOR KIPL AND KBLH...WITH
ISOLATED GUSTS IN THE 20KT RANGE STILL POSSIBLE THROUGH MIDNIGHT
LOCAL. SUSTAINED SPEEDS TO HOLD 10-15KTS GNLY THROUGH SUNRISE BEFORE
DROPPING 8KTS OR LESS FOR WEDNESDAY MORNING. IN THE WAKE OF A DRY
COOL FRONT PASSAGE...SKIES WILL REMAIN MOSTLY CLEAR THROUGH WEDNESDAY
MORNING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
STRONG UPPER LEVEL LOW WILL APPROACH THE AREA ON FRIDAY AND MOVE
THROUGH ARIZONA/CALIFORNIA ON SATURDAY. AHEAD OF THE TROUGH...WINDS
WILL INCREASE QUITE A BIT FRIDAY AFTERNOON AND ITS POSSIBLE CRITICAL
THRESHOLDS COULD BE REALIZED IN SOME PARTS OF THE FORECAST AREA.
STILL NEED A LITTLE BETTER CONSISTENCY IN THE MODELS BEFORE GOING
WITH A FIRE WX WATCH AND WILL HOLD OFF AT THIS POINT. TEMPERATURES
ON SATURDAY AND SUNDAY /POST-TROUGH/ WILL BE SUBSTANTIALLY COOLER
AND HUMIDITIES WILL RECOVER QUITE A BIT...THUS FIRE WEATHER CONCERNS
WILL BE MUCH LESS. TEMPS WILL RECOVER NEXT WEEK AND CONSEQUENTLY
AFTERNOON HUMIDITIES WILL ONCE AGAIN DROP INTO THE SINGLE DIGITS.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...NOLTE
PREVIOUS DISCUSSION...AJ/MEYERS
AVIATION....NOLTE
FIRE WEATHER...LEINS/MO






000
FXUS65 KPSR 222244
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
345 PM MST TUE APR 22 2014


.SYNOPSIS...
BREEZY TO WINDY CONDITIONS WILL SLOWLY DECREASE TONIGHT AS A DRY
WEATHER SYSTEM PASSES ACROSS ARIZONA. ANTICIPATE COOLER HIGH
TEMPERATURES WEDNESDAY WITH READINGS CLOSE TO NORMAL. SOMEWHAT
WARMER TEMPERATURES CAN BE EXPECTED THURSDAY. ANOTHER LOW PRESSURE
SYSTEM WILL AFFECT THE REGION FRIDAY AND SATURDAY. BREEZY TO WINDY
CONDITIONS CAN BE EXPECTED ALONG WITH MUCH COOLER TEMPERATURES
SATURDAY. THERE IS ALSO A SLIGHT CHANCE OF SHOWERS LATE FRIDAY NIGHT
INTO SATURDAY NIGHT...MAINLY FOR THE HIGHER TERRAIN OF SOUTH-CENTRAL
ARIZONA. ANTICIPATE A WARMING TREND MONDAY AND TUESDAY.

&&

.DISCUSSION...
WATER VAPOR IMAGERY SHOWS UPPER TROUGH CENTERED OVER THE PACIFIC
COAST. SURFACE AND UPPER AIR OBS INDICATE THE ASSOCIATED FRONT IS
OVER NEVADA AND SOUTHERN CALIFORNIA AS OF 16Z. THE FRONT IS
ANTICIPATED TO MOVE INTO MARICOPA COUNTY LATER THIS AFTERNOON.
COOLING FOR THE PHOENIX AREA WILL BE QUITE SUBTLE...MORE NOTICEABLE
FURTHER WEST. MAIN CLOUD BAND THAT WILL MOVE OVER OUR AREA IS ALONG
AND AHEAD OF THE FRONT BUT MAINLY JUST HIGH CLOUDS. MODELS INDICATE
THAT WE MAY ADDITIONALLY HAVE SOME CUMULUS/ALTOCUMULUS WITH THE
FRONTAL ZONE. LIMITED MOISTURE IS SUPPORTED BY PRECIPITABLE WATER
VALUES TRENDING DOWNWARD WITH THE SYSTEM PER BLENDED TPW SATELLITE
IMAGERY. MODELS INDICATE ONLY A SMALL BATCH OF CAPE NEAR THE YUMA
COUNTY/MEXICO BORDER THIS AFTERNOON. THEY ALSO DEPICT SOMEWHAT LOWER
LIFTED INDEX VALUES WITH THE FRONTAL ZONE THIS AFTERNOON AND EVENING
BUT OVERALL TOO LITTLE TO MENTION THUNDERSTORM POTENTIAL. SYSTEMS
WITH LIMITED MOISTURE ARE QUITE TYPICAL THIS TIME OF YEAR...MAINLY
JUST WIND PRODUCERS. UNFORTUNATELY THAT MEANS ELEVATED FIRE WEATHER
CONCERNS WITH THE STRONG WINDS AND LOW HUMIDITIES. IN FACT...A RED
FLAG WARNING REMAINS IN EFFECT FOR THE LOWER COLORADO RIVER VALLEY
AND THE SOUTHWEST AND SOUTH-CENTRAL ARIZONA DESERTS...MAIN EMPHASIS
WEST OF MARICOPA COUNTY. MORE LATER.

&&

.PREVIOUS DISCUSSION ISSUED 325 AM...
REST OF TODAY THROUGH THURSDAY...
WINDS HAVE BEEN PICKING UP WITH REGULAR GUSTS OF AROUND 30 MPH SO
FAR IN SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA AND 20-25 MPH IN
SOUTH-CENTRAL ARIZONA. SOME STRONGER WINDS YET TO COME AS THE
SURFACE LOW OVER AND NEAR THE NV/UT BORDER CONTINUES TO DEEPEN AND
THE DRY FRONT STARTS MOVING INTO ARIZONA LATER THIS AFTERNOON. THE
RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MST/PDT. NO EPISODES
OF DENSE BLOWING DUST SO FAR THAT WE ARE AWARE OF BUT LOCALIZED
BRIEF EPISODES IN THE DUST PRONE AREAS REMAINS A POSSIBILITY. 24 HR
TEMPERATURE TRENDS RUNNING AT LEAST A FEW DEGREES COOLER WESTERN
PORTIONS OF THE FORECAST AREA...LITTLE CHANGE EASTERN PORTIONS.
BEHIND THE FRONT ON WEDNESDAY LOOK FOR HIGHS IN THE UPPER 80S ACROSS
THE LOWER DESERTS. ANTICIPATE LESS WIND THOUGH A TRAILING SHORT WAVE
WILL MAINTAIN SOME BREEZINESS. A FLAT RIDGE PASSES BY THURSDAY WITH
HIGHS A FEW DEGREES WARMER.

FRIDAY THROUGH SUNDAY...
THE NEXT PACIFIC SYSTEM WILL AFFECT OUR FORECAST AREA FRIDAY AND
SATURDAY. THE GFS CONTINUES TO BE A BIT FASTER THAN THE ECWMF...WITH
THE GEM IN BETWEEN. IN SHORT...BREEZY TO WINDY CONDITIONS DEVELOP
FRIDAY AFTERNOON...WITH BREEZINESS CONTINUING FRIDAY NIGHT AND
SATURDAY. SPEEDS FRIDAY AFTERNOON ARE LOOKING QUITE SIMILAR TO
TODAY...TUESDAY. EVENING AND OVERNIGHT BREEZINESS WILL BE STRONGER
THOUGH. THUS ANTICIPATE RED FLAG POTENTIAL AND POSSIBLY WIND
ADVISORY CONDITIONS SIMILAR TO TODAY. THE NEXT SYSTEM WILL DIG
DEEPER AND BRING EVEN COOLER AIR. MADE SOME SLIGHT DOWNWARD
ADJUSTMENTS TO THE HIGHS FOR SATURDAY WITH LOWER DESERT HIGHS IN
UPPER 70S. ALSO INTRODUCED SOME SLIGHT CHANCE POPS IN PORTIONS OF
OUR FORECAST AREA FOR LATE FRIDAY NIGHT INTO SATURDAY NIGHT...MAINLY
THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA. ANTICIPATE SLIGHTLY
WARMER HIGHS SUNDAY WITH DRY NORTHWEST FLOW ALOFT.

MONDAY AND TUESDAY...
THE FLOW AMPLIFIES EARLY NEXT WEEK FOR RIDGING OVER THE WEST COAST
FOR A WARMING TREND. LINGERING TROUGHING OVER THE CENTRAL CONUS MAY
KEEP THE TEMPS FROM SHOOTING UP EXCESSIVELY...BUT STILL LOOK FOR
HIGHS GETTING INTO THE 90S BY TUESDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
WINDS ARE SLOWLY INCREASING ACROSS THE PHOENIX AREA AND HAVE ALREADY
COME AROUND OUT OF THE SOUTHWEST. FORTUNATELY THIS MEANS THE STRONG
180 DEGREE CROSSWIND AT PHX WONT MATERIALIZE AND WINDS SHOULD
RETAIN A WESTERLY COMPONENT THROUGH THE REST OF THE AFTERNOON AND
EVENING. EXPECT WINDS TO PEAK AROUND 15G25KTS AROUND 00Z AND SLOWLY
SLACK OFF INTO THE EVENING. THE GUSTINESS SHOULD DISSIPATE AROUND
03Z BASED ON LATEST MODEL GUIDANCE. WHILE BLDU IS A POSSIBILITY THIS
AFTERNOON...DUST WOULD BE VERY LOCALIZED AND I AM NOT GOING TO
INCLUDE IT IN THE TAFS.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
GUSTY WEST WINDS INCREASING ALREADY AND SHOULD REMAIN ELEVATED
THROUGH AT LEAST 03Z. EXPECT 20G30KTS AT BOTH IPL/BLH THROUGH EARLY
EVENING. BLDU AND BLSA CERTAINLY POSSIBLE BUT SHOULD BE VERY
LOCALIZED IN NATURE. WILL NOT INCLUDE IN EITHER TAF. LIGHTER WINDS
EXPECTED ON WEDNESDAY.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
STRONG UPPER LEVEL LOW WILL APPROACH THE AREA ON FRIDAY AND MOVE
THROUGH ARIZONA/CALIFORNIA ON SATURDAY. AHEAD OF THE TROUGH...WINDS
WILL INCREASE QUITE A BIT FRIDAY AFTERNOON AND ITS POSSIBLE CRITICAL
THRESHOLDS COULD BE REALIZED IN SOME PARTS OF THE FORECAST AREA.
STILL NEED A LITTLE BETTER CONSISTENCY IN THE MODELS BEFORE GOING
WITH A FIRE WX WATCH AND WILL HOLD OFF AT THIS POINT. TEMPERATURES
ON SATURDAY AND SUNDAY /POST-TROUGH/ WILL BE SUBSTANTIALLY COOLER
AND HUMIDITIES WILL RECOVER QUITE A BIT...THUS FIRE WEATHER CONCERNS
WILL BE MUCH LESS. TEMPS WILL RECOVER NEXT WEEK AND CONSEQUENTLY
AFTERNOON HUMIDITIES WILL ONCE AGAIN DROP INTO THE SINGLE DIGITS.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...RED FLAG WARNING FOR FIRE ZONES AZZ131 AND AZZ132 UNTIL 8 PM.

CA...RED FLAG WARNING FIRE ZONE CAZ231 UNTIL 8 PM.

&&

$$

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

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








000
FXUS65 KPSR 222244
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
345 PM MST TUE APR 22 2014


.SYNOPSIS...
BREEZY TO WINDY CONDITIONS WILL SLOWLY DECREASE TONIGHT AS A DRY
WEATHER SYSTEM PASSES ACROSS ARIZONA. ANTICIPATE COOLER HIGH
TEMPERATURES WEDNESDAY WITH READINGS CLOSE TO NORMAL. SOMEWHAT
WARMER TEMPERATURES CAN BE EXPECTED THURSDAY. ANOTHER LOW PRESSURE
SYSTEM WILL AFFECT THE REGION FRIDAY AND SATURDAY. BREEZY TO WINDY
CONDITIONS CAN BE EXPECTED ALONG WITH MUCH COOLER TEMPERATURES
SATURDAY. THERE IS ALSO A SLIGHT CHANCE OF SHOWERS LATE FRIDAY NIGHT
INTO SATURDAY NIGHT...MAINLY FOR THE HIGHER TERRAIN OF SOUTH-CENTRAL
ARIZONA. ANTICIPATE A WARMING TREND MONDAY AND TUESDAY.

&&

.DISCUSSION...
WATER VAPOR IMAGERY SHOWS UPPER TROUGH CENTERED OVER THE PACIFIC
COAST. SURFACE AND UPPER AIR OBS INDICATE THE ASSOCIATED FRONT IS
OVER NEVADA AND SOUTHERN CALIFORNIA AS OF 16Z. THE FRONT IS
ANTICIPATED TO MOVE INTO MARICOPA COUNTY LATER THIS AFTERNOON.
COOLING FOR THE PHOENIX AREA WILL BE QUITE SUBTLE...MORE NOTICEABLE
FURTHER WEST. MAIN CLOUD BAND THAT WILL MOVE OVER OUR AREA IS ALONG
AND AHEAD OF THE FRONT BUT MAINLY JUST HIGH CLOUDS. MODELS INDICATE
THAT WE MAY ADDITIONALLY HAVE SOME CUMULUS/ALTOCUMULUS WITH THE
FRONTAL ZONE. LIMITED MOISTURE IS SUPPORTED BY PRECIPITABLE WATER
VALUES TRENDING DOWNWARD WITH THE SYSTEM PER BLENDED TPW SATELLITE
IMAGERY. MODELS INDICATE ONLY A SMALL BATCH OF CAPE NEAR THE YUMA
COUNTY/MEXICO BORDER THIS AFTERNOON. THEY ALSO DEPICT SOMEWHAT LOWER
LIFTED INDEX VALUES WITH THE FRONTAL ZONE THIS AFTERNOON AND EVENING
BUT OVERALL TOO LITTLE TO MENTION THUNDERSTORM POTENTIAL. SYSTEMS
WITH LIMITED MOISTURE ARE QUITE TYPICAL THIS TIME OF YEAR...MAINLY
JUST WIND PRODUCERS. UNFORTUNATELY THAT MEANS ELEVATED FIRE WEATHER
CONCERNS WITH THE STRONG WINDS AND LOW HUMIDITIES. IN FACT...A RED
FLAG WARNING REMAINS IN EFFECT FOR THE LOWER COLORADO RIVER VALLEY
AND THE SOUTHWEST AND SOUTH-CENTRAL ARIZONA DESERTS...MAIN EMPHASIS
WEST OF MARICOPA COUNTY. MORE LATER.

&&

.PREVIOUS DISCUSSION ISSUED 325 AM...
REST OF TODAY THROUGH THURSDAY...
WINDS HAVE BEEN PICKING UP WITH REGULAR GUSTS OF AROUND 30 MPH SO
FAR IN SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA AND 20-25 MPH IN
SOUTH-CENTRAL ARIZONA. SOME STRONGER WINDS YET TO COME AS THE
SURFACE LOW OVER AND NEAR THE NV/UT BORDER CONTINUES TO DEEPEN AND
THE DRY FRONT STARTS MOVING INTO ARIZONA LATER THIS AFTERNOON. THE
RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MST/PDT. NO EPISODES
OF DENSE BLOWING DUST SO FAR THAT WE ARE AWARE OF BUT LOCALIZED
BRIEF EPISODES IN THE DUST PRONE AREAS REMAINS A POSSIBILITY. 24 HR
TEMPERATURE TRENDS RUNNING AT LEAST A FEW DEGREES COOLER WESTERN
PORTIONS OF THE FORECAST AREA...LITTLE CHANGE EASTERN PORTIONS.
BEHIND THE FRONT ON WEDNESDAY LOOK FOR HIGHS IN THE UPPER 80S ACROSS
THE LOWER DESERTS. ANTICIPATE LESS WIND THOUGH A TRAILING SHORT WAVE
WILL MAINTAIN SOME BREEZINESS. A FLAT RIDGE PASSES BY THURSDAY WITH
HIGHS A FEW DEGREES WARMER.

FRIDAY THROUGH SUNDAY...
THE NEXT PACIFIC SYSTEM WILL AFFECT OUR FORECAST AREA FRIDAY AND
SATURDAY. THE GFS CONTINUES TO BE A BIT FASTER THAN THE ECWMF...WITH
THE GEM IN BETWEEN. IN SHORT...BREEZY TO WINDY CONDITIONS DEVELOP
FRIDAY AFTERNOON...WITH BREEZINESS CONTINUING FRIDAY NIGHT AND
SATURDAY. SPEEDS FRIDAY AFTERNOON ARE LOOKING QUITE SIMILAR TO
TODAY...TUESDAY. EVENING AND OVERNIGHT BREEZINESS WILL BE STRONGER
THOUGH. THUS ANTICIPATE RED FLAG POTENTIAL AND POSSIBLY WIND
ADVISORY CONDITIONS SIMILAR TO TODAY. THE NEXT SYSTEM WILL DIG
DEEPER AND BRING EVEN COOLER AIR. MADE SOME SLIGHT DOWNWARD
ADJUSTMENTS TO THE HIGHS FOR SATURDAY WITH LOWER DESERT HIGHS IN
UPPER 70S. ALSO INTRODUCED SOME SLIGHT CHANCE POPS IN PORTIONS OF
OUR FORECAST AREA FOR LATE FRIDAY NIGHT INTO SATURDAY NIGHT...MAINLY
THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA. ANTICIPATE SLIGHTLY
WARMER HIGHS SUNDAY WITH DRY NORTHWEST FLOW ALOFT.

MONDAY AND TUESDAY...
THE FLOW AMPLIFIES EARLY NEXT WEEK FOR RIDGING OVER THE WEST COAST
FOR A WARMING TREND. LINGERING TROUGHING OVER THE CENTRAL CONUS MAY
KEEP THE TEMPS FROM SHOOTING UP EXCESSIVELY...BUT STILL LOOK FOR
HIGHS GETTING INTO THE 90S BY TUESDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
WINDS ARE SLOWLY INCREASING ACROSS THE PHOENIX AREA AND HAVE ALREADY
COME AROUND OUT OF THE SOUTHWEST. FORTUNATELY THIS MEANS THE STRONG
180 DEGREE CROSSWIND AT PHX WONT MATERIALIZE AND WINDS SHOULD
RETAIN A WESTERLY COMPONENT THROUGH THE REST OF THE AFTERNOON AND
EVENING. EXPECT WINDS TO PEAK AROUND 15G25KTS AROUND 00Z AND SLOWLY
SLACK OFF INTO THE EVENING. THE GUSTINESS SHOULD DISSIPATE AROUND
03Z BASED ON LATEST MODEL GUIDANCE. WHILE BLDU IS A POSSIBILITY THIS
AFTERNOON...DUST WOULD BE VERY LOCALIZED AND I AM NOT GOING TO
INCLUDE IT IN THE TAFS.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
GUSTY WEST WINDS INCREASING ALREADY AND SHOULD REMAIN ELEVATED
THROUGH AT LEAST 03Z. EXPECT 20G30KTS AT BOTH IPL/BLH THROUGH EARLY
EVENING. BLDU AND BLSA CERTAINLY POSSIBLE BUT SHOULD BE VERY
LOCALIZED IN NATURE. WILL NOT INCLUDE IN EITHER TAF. LIGHTER WINDS
EXPECTED ON WEDNESDAY.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
STRONG UPPER LEVEL LOW WILL APPROACH THE AREA ON FRIDAY AND MOVE
THROUGH ARIZONA/CALIFORNIA ON SATURDAY. AHEAD OF THE TROUGH...WINDS
WILL INCREASE QUITE A BIT FRIDAY AFTERNOON AND ITS POSSIBLE CRITICAL
THRESHOLDS COULD BE REALIZED IN SOME PARTS OF THE FORECAST AREA.
STILL NEED A LITTLE BETTER CONSISTENCY IN THE MODELS BEFORE GOING
WITH A FIRE WX WATCH AND WILL HOLD OFF AT THIS POINT. TEMPERATURES
ON SATURDAY AND SUNDAY /POST-TROUGH/ WILL BE SUBSTANTIALLY COOLER
AND HUMIDITIES WILL RECOVER QUITE A BIT...THUS FIRE WEATHER CONCERNS
WILL BE MUCH LESS. TEMPS WILL RECOVER NEXT WEEK AND CONSEQUENTLY
AFTERNOON HUMIDITIES WILL ONCE AGAIN DROP INTO THE SINGLE DIGITS.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...RED FLAG WARNING FOR FIRE ZONES AZZ131 AND AZZ132 UNTIL 8 PM.

CA...RED FLAG WARNING FIRE ZONE CAZ231 UNTIL 8 PM.

&&

$$

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

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







000
FXUS65 KPSR 222007 AAA
AFDPSR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PHOENIX AZ
107 PM MST TUE APR 22 2014

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

&&

.SYNOPSIS...
BREEZY TO WINDY CONDITIONS WILL DEVELOP OVER MUCH OF THE AREA THIS
AFTERNOON INTO WEDNESDAY AS A DRY WEATHER SYSTEM PASSES TO THE
NORTH. TEMPERATURES WILL FALL IN RESPONSE TO THIS WEATHER SYSTEM...
AND LOWER TO AROUND SEASONAL NORMALS BY WEDNESDAY.  A SLIGHT WARMING
TREND WILL OCCUR THURSDAY INTO FRIDAY AS HIGHER PRESSURE ALOFT
RETURNS TO THE AREA...BEFORE ANOTHER VIGOROUS PACIFIC UPPER LEVEL
LOW PRESSURE SYSTEM BRINGS SIGNIFICANT WIND AND COOLING TO THE AREA
OVER THE WEEKEND.

&&

.DISCUSSION...
WATER VAPOR IMAGERY SHOWS UPPER TROUGH CENTERED OVER THE PACIFIC
COAST. SURFACE AND UPPER AIR OBS INDICATE THE ASSOCIATED FRONT IS
OVER NEVADA AND SOUTHERN CALIFORNIA AS OF 16Z. THE FRONT IS
ANTICIPATED TO MOVE INTO MARICOPA COUNTY LATER THIS AFTERNOON.
COOLING FOR THE PHOENIX AREA WILL BE QUITE SUBTLE...MORE NOTICEABLE
FURTHER WEST. MAIN CLOUD BAND THAT WILL MOVE OVER OUR AREA IS ALONG
AND AHEAD OF THE FRONT BUT MAINLY JUST HIGH CLOUDS. MODELS INDICATE
THAT WE MAY ADDITIONALLY HAVE SOME CUMULUS/ALTOCUMULUS WITH THE
FRONTAL ZONE. LIMITED MOISTURE IS SUPPORTED BY PRECIPITABLE WATER
VALUES TRENDING DOWNWARD WITH THE SYSTEM PER BLENDED TPW SATELLITE
IMAGERY. MODELS INDICATE ONLY A SMALL BATCH OF CAPE NEAR THE YUMA
COUNTY/MEXICO BORDER THIS AFTERNOON. THEY ALSO DEPICT SOMEWHAT LOWER
LIFTED INDEX VALUES WITH THE FRONTAL ZONE THIS AFTERNOON AND EVENING
BUT OVERALL TOO LITTLE TO MENTION THUNDERSTORM POTENTIAL. SYSTEMS
WITH LIMITED MOISTURE ARE QUITE TYPICAL THIS TIME OF YEAR...MAINLY
JUST WIND PRODUCERS. UNFORTUNATELY THAT MEANS ELEVATED FIRE WEATHER
CONCERNS WITH THE STRONG WINDS AND LOW HUMIDITIES. IN FACT...A RED
FLAG WARNING REMAINS IN EFFECT FOR THE LOWER COLORADO RIVER VALLEY
AND THE SOUTHWEST AND SOUTH-CENTRAL ARIZONA DESERTS...MAIN EMPHASIS
WEST OF MARICOPA COUNTY. MORE LATER.

&&

.PREVIOUS DISCUSSION ISSUED 325 AM...
WATER VAPOR IMAGERY REVEALS OUR NEXT WEATHER SYSTEM CURRENTLY MOVING
INLAND ALONG THE WEST COAST...THE CENTER OF THE 533DM LOW SPINNING
IN THE PACIFIC WEST OF BRITISH COLUMBIA...THE SOUTHERN EXTENT OF THE
TROUGH IMPACTING CENTRAL AND NORTHERN CALIFORNIA. FURTHER SOUTH AND
AHEAD OF THE TROUGH...BANDS OF HIGH CLOUDS ARE STREAMING ACROSS
SOUTHEAST CALIFORNIA INTO NEVADA AND WESTERN ARIZONA THIS MORNING.
MID AND LOWER LEVEL PRESSURE GRADIENTS CONTINUE TO TIGHTEN...AND THE
LOW LEVEL WIND FIELDS ARE BEGINNING TO RESPOND THROUGH PORTIONS OF
THE SIERRA NEVADA IN CALIFORNIA WITH SOME GUSTS UP TO 30 MPH NOTED
IN SURFACE OBSERVATIONS.

THE INFLUENCE OF THE TROUGH WILL BE FELT ACROSS OUR CWA LATER THIS
AFTERNOON AND EVENING...WITH STRONG GUSTY WINDS OF 20-25 MPH AND
LOCAL GUSTS TO 35 MPH COMMON ACROSS SOUTHEAST CALIFORNIA AND
SOUTHWEST ARIZONA. SOME LOCATIONS IN AND AROUND THE IMPERIAL
VALLEY/EL CENTRO CA...JOSHUA TREE NATIONAL PARK...AND OTHER HIGHER
TERRAIN AREAS IN LA PAZ COUNTY AZ MAY EXPERIENCE STRONGER WIND GUSTS
ALONG WITH AREAS OF BLOWING DUST/SAND. RIGHT NOW...FORECAST WIND
SPEEDS ARE NOT MEETING WIND ADVISORY CRITERIA...BUT IT WILL BE
SOMETHING TO MONITOR.

GIVEN THE DRY NATURE OF THE TROUGH AND FRONTAL PASSAGE...THE WINDS
WILL ONLY CONTRIBUTE TO DANGEROUS FIRE WEATHER CONDITIONS. AS
SUCH...A RED FLAG WARNING IS IN EFFECT FROM 2 TO 8 PM TODAY FOR
SOUTHWEST ARIZONA INCLUDING THE LOWER COLORADO RIVER VALLEY. THE
SYSTEM WILL ALSO BRING 8-10 DEGREES OF COOLING...LOWERING DAYTIME
TEMPERATURES BACK INTO THE MID TO UPPER 80S OVER THE LOWER DESERTS.

SHORTWAVE RIDGING COMMENCES THURSDAY...WITH 500MB HEIGHTS REBOUNDING
TO NEAR 576DM OVER SOUTHERN CALIFORNIA AND SOUTH-CENTRAL ARIZONA BY
FRIDAY. HOWEVER...ANOTHER POTENT UPPER LEVEL TROUGH WILL MOVE INTO
THE REGION LATE FRIDAY AND ONCE AGAIN BRING ANOTHER ROUND OF COOLER
TEMPERATURES AND INCREASED WINDS THIS WEEKEND.

THE GFS/ECMWF ARE NOW IN MUCH BETTER AGREEMENT WITH THIS NEXT
SYSTEM...EVEN THOUGH THERE ARE STILL SOME TIMING DIFFERENCES. BOTH
PLACE A 542-556DM UPPER LEVEL LOW/OPEN WAVE OVER NEVADA BY SATURDAY
MORNING. THE OPERATIONAL GEM MORE ALIGNED WITH THE GFS AND ECMWF...
BUT MAINTAINING A CLOSED LOW SOLUTION. AT THIS TIME...UNLESS THE
SYSTEM DIGS EVEN DEEPER WEST OF CALIFORNIA...ANY SOLUTION WILL
REMAIN CONSIDERABLY DRY WITH PRECIPITATION CHANCES SLIGHT/SLIM FOR
OUR FORECAST AREA. WITH LOWER HEIGHTS AND A TIGHTENED GRADIENT OF
555-564DM SPLAYED ACROSS SOUTHEAST CALIFORNIA AND SOUTH-CENTRAL
ARIZONA...THE FORECAST WILL CONTINUE TO DROP DAYTIME TEMPERATURES
BACK INTO THE LOW 80S...ALONG WITH BREEZY TO WINDY CONDITIONS AGAIN
SATURDAY AND SUNDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
WINDS ARE SLOWLY INCREASING ACROSS THE PHOENIX AREA AND HAVE ALREADY
COME AROUND OUT OF THE SOUTHWEST. FORTUNATELY THIS MEANS THE STRONG
180 DEGREE CROSSWIND AT PHX WONT MATERIALIZE AND WINDS SHOULD
RETAIN A WESTERLY COMPONENT THROUGH THE REST OF THE AFTERNOON AND
EVENING. EXPECT WINDS TO PEAK AROUND 15G25KTS AROUND 00Z AND SLOWLY
SLACK OFF INTO THE EVENING. THE GUSTINESS SHOULD DISSIPATE AROUND
03Z BASED ON LATEST MODEL GUIDANCE. WHILE BLDU IS A POSSIBILITY THIS
AFTERNOON...DUST WOULD BE VERY LOCALIZED AND I AM NOT GOING TO
INCLUDE IT IN THE TAFS.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
GUSTY WEST WINDS INCREASING ALREADY AND SHOULD REMAIN ELEVATED
THROUGH AT LEAST 03Z. EXPECT 20G30KTS AT BOTH IPL/BLH THROUGH EARLY
EVENING. BLDU AND BLSA CERTAINLY POSSIBLE BUT SHOULD BE VERY
LOCALIZED IN NATURE. WILL NOT INCLUDE IN EITHER TAF. LIGHTER WINDS
EXPECTED ON WEDNESDAY.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
STRONG UPPER LEVEL LOW WILL APPROACH THE AREA ON FRIDAY AND MOVE
THROUGH ARIZONA/CALIFORNIA ON SATURDAY. AHEAD OF THE TROUGH...WINDS
WILL INCREASE QUITE A BIT FRIDAY AFTERNOON AND ITS POSSIBLE CRITICAL
THRESHOLDS COULD BE REALIZED IN SOME PARTS OF THE FORECAST AREA.
STILL NEED A LITTLE BETTER CONSISTENCY IN THE MODELS BEFORE GOING
WITH A FIRE WX WATCH AND WILL HOLD OFF AT THIS POINT. TEMPERATURES
ON SATURDAY AND SUNDAY /POST-TROUGH/ WILL BE SUBSTANTIALLY COOLER
AND HUMIDITIES WILL RECOVER QUITE A BIT...THUS FIRE WEATHER CONCERNS
WILL BE MUCH LESS. TEMPS WILL RECOVER NEXT WEEK AND CONSEQUENTLY
AFTERNOON HUMIDITIES WILL ONCE AGAIN DROP INTO THE SINGLE DIGITS.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...RED FLAG WARNING TUESDAY AFTERNOON AND EVENING FOR FIRE ZONES
AZZ131 AND AZZ132...2 PM UNTIL 8 PM.

CA...RED FLAG WARNING TUESDAY AFTERNOON AND EVENING FOR FIRE ZONE
CAZ231...2 PM UNTIL 8 PM.

&&

$$

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

DISCUSSION...AJ
PREVIOUS DISCUSSION...MEYERS
AVIATION...LEINS
FIRE WEATHER...LEINS/MO







000
FXUS65 KPSR 221659
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1000 AM MST TUE APR 22 2014

.SYNOPSIS...
BREEZY TO WINDY CONDITIONS WILL DEVELOP OVER MUCH OF THE AREA THIS
AFTERNOON INTO WEDNESDAY AS A DRY WEATHER SYSTEM PASSES TO THE
NORTH. TEMPERATURES WILL FALL IN RESPONSE TO THIS WEATHER SYSTEM...
AND LOWER TO AROUND SEASONAL NORMALS BY WEDNESDAY.  A SLIGHT WARMING
TREND WILL OCCUR THURSDAY INTO FRIDAY AS HIGHER PRESSURE ALOFT
RETURNS TO THE AREA...BEFORE ANOTHER VIGOROUS PACIFIC UPPER LEVEL
LOW PRESSURE SYSTEM BRINGS SIGNIFICANT WIND AND COOLING TO THE AREA
OVER THE WEEKEND.

&&

.DISCUSSION...
WATER VAPOR IMAGERY SHOWS UPPER TROUGH CENTERED OVER THE PACIFIC
COAST. SURFACE AND UPPER AIR OBS INDICATE THE ASSOCIATED FRONT IS
OVER NEVADA AND SOUTHERN CALIFORNIA AS OF 16Z. THE FRONT IS
ANTICIPATED TO MOVE INTO MARICOPA COUNTY LATER THIS AFTERNOON.
COOLING FOR THE PHOENIX AREA WILL BE QUITE SUBTLE...MORE NOTICEABLE
FURTHER WEST. MAIN CLOUD BAND THAT WILL MOVE OVER OUR AREA IS ALONG
AND AHEAD OF THE FRONT BUT MAINLY JUST HIGH CLOUDS. MODELS INDICATE
THAT WE MAY ADDITIONALLY HAVE SOME CUMULUS/ALTOCUMULUS WITH THE
FRONTAL ZONE. LIMITED MOISTURE IS SUPPORTED BY PRECIPITABLE WATER
VALUES TRENDING DOWNWARD WITH THE SYSTEM PER BLENDED TPW SATELLITE
IMAGERY. MODELS INDICATE ONLY A SMALL BATCH OF CAPE NEAR THE YUMA
COUNTY/MEXICO BORDER THIS AFTERNOON. THEY ALSO DEPICT SOMEWHAT LOWER
LIFTED INDEX VALUES WITH THE FRONTAL ZONE THIS AFTERNOON AND EVENING
BUT OVERALL TOO LITTLE TO MENTION THUNDERSTORM POTENTIAL. SYSTEMS
WITH LIMITED MOISTURE ARE QUITE TYPICAL THIS TIME OF YEAR...MAINLY
JUST WIND PRODUCERS. UNFORTUNATELY THAT MEANS ELEVATED FIRE WEATHER
CONCERNS WITH THE STRONG WINDS AND LOW HUMIDITIES. IN FACT...A RED
FLAG WARNING REMAINS IN EFFECT FOR THE LOWER COLORADO RIVER VALLEY
AND THE SOUTHWEST AND SOUTH-CENTRAL ARIZONA DESERTS...MAIN EMPHASIS
WEST OF MARICOPA COUNTY. MORE LATER.

&&

.PREVIOUS DISCUSSION ISSUED 325 AM...
WATER VAPOR IMAGERY REVEALS OUR NEXT WEATHER SYSTEM CURRENTLY MOVING
INLAND ALONG THE WEST COAST...THE CENTER OF THE 533DM LOW SPINNING
IN THE PACIFIC WEST OF BRITISH COLUMBIA...THE SOUTHERN EXTENT OF THE
TROUGH IMPACTING CENTRAL AND NORTHERN CALIFORNIA. FURTHER SOUTH AND
AHEAD OF THE TROUGH...BANDS OF HIGH CLOUDS ARE STREAMING ACROSS
SOUTHEAST CALIFORNIA INTO NEVADA AND WESTERN ARIZONA THIS MORNING.
MID AND LOWER LEVEL PRESSURE GRADIENTS CONTINUE TO TIGHTEN...AND THE
LOW LEVEL WIND FIELDS ARE BEGINNING TO RESPOND THROUGH PORTIONS OF
THE SIERRA NEVADA IN CALIFORNIA WITH SOME GUSTS UP TO 30 MPH NOTED
IN SURFACE OBSERVATIONS.

THE INFLUENCE OF THE TROUGH WILL BE FELT ACROSS OUR CWA LATER THIS
AFTERNOON AND EVENING...WITH STRONG GUSTY WINDS OF 20-25 MPH AND
LOCAL GUSTS TO 35 MPH COMMON ACROSS SOUTHEAST CALIFORNIA AND
SOUTHWEST ARIZONA. SOME LOCATIONS IN AND AROUND THE IMPERIAL
VALLEY/EL CENTRO CA...JOSHUA TREE NATIONAL PARK...AND OTHER HIGHER
TERRAIN AREAS IN LA PAZ COUNTY AZ MAY EXPERIENCE STRONGER WIND GUSTS
ALONG WITH AREAS OF BLOWING DUST/SAND. RIGHT NOW...FORECAST WIND
SPEEDS ARE NOT MEETING WIND ADVISORY CRITERIA...BUT IT WILL BE
SOMETHING TO MONITOR.

GIVEN THE DRY NATURE OF THE TROUGH AND FRONTAL PASSAGE...THE WINDS
WILL ONLY CONTRIBUTE TO DANGEROUS FIRE WEATHER CONDITIONS. AS
SUCH...A RED FLAG WARNING IS IN EFFECT FROM 2 TO 8 PM TODAY FOR
SOUTHWEST ARIZONA INCLUDING THE LOWER COLORADO RIVER VALLEY. THE
SYSTEM WILL ALSO BRING 8-10 DEGREES OF COOLING...LOWERING DAYTIME
TEMPERATURES BACK INTO THE MID TO UPPER 80S OVER THE LOWER DESERTS.

SHORTWAVE RIDGING COMMENCES THURSDAY...WITH 500MB HEIGHTS REBOUNDING
TO NEAR 576DM OVER SOUTHERN CALIFORNIA AND SOUTH-CENTRAL ARIZONA BY
FRIDAY. HOWEVER...ANOTHER POTENT UPPER LEVEL TROUGH WILL MOVE INTO
THE REGION LATE FRIDAY AND ONCE AGAIN BRING ANOTHER ROUND OF COOLER
TEMPERATURES AND INCREASED WINDS THIS WEEKEND.

THE GFS/ECMWF ARE NOW IN MUCH BETTER AGREEMENT WITH THIS NEXT
SYSTEM...EVEN THOUGH THERE ARE STILL SOME TIMING DIFFERENCES. BOTH
PLACE A 542-556DM UPPER LEVEL LOW/OPEN WAVE OVER NEVADA BY SATURDAY
MORNING. THE OPERATIONAL GEM MORE ALIGNED WITH THE GFS AND ECMWF...
BUT MAINTAINING A CLOSED LOW SOLUTION. AT THIS TIME...UNLESS THE
SYSTEM DIGS EVEN DEEPER WEST OF CALIFORNIA...ANY SOLUTION WILL
REMAIN CONSIDERABLY DRY WITH PRECIPITATION CHANCES SLIGHT/SLIM FOR
OUR FORECAST AREA. WITH LOWER HEIGHTS AND A TIGHTENED GRADIENT OF
555-564DM SPLAYED ACROSS SOUTHEAST CALIFORNIA AND SOUTH-CENTRAL
ARIZONA...THE FORECAST WILL CONTINUE TO DROP DAYTIME TEMPERATURES
BACK INTO THE LOW 80S...ALONG WITH BREEZY TO WINDY CONDITIONS AGAIN
SATURDAY AND SUNDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
WINDS WILL BE THE MAIN AVIATION CONCERN THROUGH WEDNESDAY
MORNING...WITH INCREASING SPEEDS AND FREQUENT GUSTS DEVELOPING THIS
AFTERNOON THROUGH EARLY EVENING. THE LARGEST PROBLEM MAY BE A
PROLONGED SEVERAL HOUR PERIOD OF A SOUTHERLY CROSS COMPONENT LATE
MORNING/EARLY AFTERNOON. ANY GUSTS ASSOCIATED WITH A DUE SOUTH WIND
SHOULD REMAIN AOB 20KT...BEFORE THE DIRECTION VEERS TOWARDS A MORE
SWLY/WLY DIRECTION LATER IN THE AFTERNOON. GUSTS SHOULD SUBSIDE
LATER THIS EVENING...HOWEVER FORECAST CONFIDENCE IN TIMING THE LOSS
OF GUSTINESS IS LOW.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
STRONG SFC WINDS WILL BE THE LARGEST AVIATION CONCERN ACROSS SE
CALIFORNIA THIS AFTERNOON AND EVENING. A WLY COMPONENT AT KIPL AND
SLY WIND AT KBLH WILL BOTH BEGIN GUSTING ABOVE 20KT BY LATE MORNING.
EVENTUALLY WINDS AT BOTH AIRFIELDS WILL BECOMING SWLY BY LATE
AFTERNOON WITH FREQUENT GUSTS TO AROUND 30KT DEVELOPING. NOCTURNAL
DECOUPLING SHOULD ALLOW GUSTS TO SUBSIDE LATER THIS
EVENING...HOWEVER THE FORECAST CONFIDENCE IN TIMING WHEN WIND SPEEDS
BEGIN TO DECREASE IS LOW.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
WEAK HIGH PRESSURE AND RELATIVELY LIGHT WINDS THURSDAY WILL BE
REPLACED BY A STRONG PACIFIC WEATHER SYSTEM MOVING NORTH OF THE
DISTRICT FRIDAY AND SATURDAY. THIS SYSTEM WILL ALLOW WINDS TO
INCREASE IN A SIMILAR FASHION TO TODAY...YIELDING AN ELEVATED FIRE
DANGER WITH HUMIDITY LEVELS FALLING INTO THE LOWER TEENS AND WIND
GUSTS APPROACHING 30 MPH. MORE TRANQUIL WEATHER CONDITIONS ARE
LIKELY NEXT WEEK WITH A WARMING TREND...ALBEIT WITH MINIMUM HUMIDITY
LEVELS FALLING BACK INTO THE SINGLE DIGITS AND ONLY FAIR OVERNIGHT
RECOVERY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...RED FLAG WARNING TUESDAY AFTERNOON AND EVENING FOR FIRE ZONES
AZZ131 AND AZZ132...2 PM UNTIL 8 PM.

CA...RED FLAG WARNING TUESDAY AFTERNOON AND EVENING FOR FIRE ZONE
CAZ231...2 PM UNTIL 8 PM.

&&

$$

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

DISCUSSION...AJ
PREVIOUS DISCUSSION...MEYERS
AVIATION...MO
FIRE WEATHER...MO







000
FXUS65 KPSR 221659
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1000 AM MST TUE APR 22 2014

.SYNOPSIS...
BREEZY TO WINDY CONDITIONS WILL DEVELOP OVER MUCH OF THE AREA THIS
AFTERNOON INTO WEDNESDAY AS A DRY WEATHER SYSTEM PASSES TO THE
NORTH. TEMPERATURES WILL FALL IN RESPONSE TO THIS WEATHER SYSTEM...
AND LOWER TO AROUND SEASONAL NORMALS BY WEDNESDAY.  A SLIGHT WARMING
TREND WILL OCCUR THURSDAY INTO FRIDAY AS HIGHER PRESSURE ALOFT
RETURNS TO THE AREA...BEFORE ANOTHER VIGOROUS PACIFIC UPPER LEVEL
LOW PRESSURE SYSTEM BRINGS SIGNIFICANT WIND AND COOLING TO THE AREA
OVER THE WEEKEND.

&&

.DISCUSSION...
WATER VAPOR IMAGERY SHOWS UPPER TROUGH CENTERED OVER THE PACIFIC
COAST. SURFACE AND UPPER AIR OBS INDICATE THE ASSOCIATED FRONT IS
OVER NEVADA AND SOUTHERN CALIFORNIA AS OF 16Z. THE FRONT IS
ANTICIPATED TO MOVE INTO MARICOPA COUNTY LATER THIS AFTERNOON.
COOLING FOR THE PHOENIX AREA WILL BE QUITE SUBTLE...MORE NOTICEABLE
FURTHER WEST. MAIN CLOUD BAND THAT WILL MOVE OVER OUR AREA IS ALONG
AND AHEAD OF THE FRONT BUT MAINLY JUST HIGH CLOUDS. MODELS INDICATE
THAT WE MAY ADDITIONALLY HAVE SOME CUMULUS/ALTOCUMULUS WITH THE
FRONTAL ZONE. LIMITED MOISTURE IS SUPPORTED BY PRECIPITABLE WATER
VALUES TRENDING DOWNWARD WITH THE SYSTEM PER BLENDED TPW SATELLITE
IMAGERY. MODELS INDICATE ONLY A SMALL BATCH OF CAPE NEAR THE YUMA
COUNTY/MEXICO BORDER THIS AFTERNOON. THEY ALSO DEPICT SOMEWHAT LOWER
LIFTED INDEX VALUES WITH THE FRONTAL ZONE THIS AFTERNOON AND EVENING
BUT OVERALL TOO LITTLE TO MENTION THUNDERSTORM POTENTIAL. SYSTEMS
WITH LIMITED MOISTURE ARE QUITE TYPICAL THIS TIME OF YEAR...MAINLY
JUST WIND PRODUCERS. UNFORTUNATELY THAT MEANS ELEVATED FIRE WEATHER
CONCERNS WITH THE STRONG WINDS AND LOW HUMIDITIES. IN FACT...A RED
FLAG WARNING REMAINS IN EFFECT FOR THE LOWER COLORADO RIVER VALLEY
AND THE SOUTHWEST AND SOUTH-CENTRAL ARIZONA DESERTS...MAIN EMPHASIS
WEST OF MARICOPA COUNTY. MORE LATER.

&&

.PREVIOUS DISCUSSION ISSUED 325 AM...
WATER VAPOR IMAGERY REVEALS OUR NEXT WEATHER SYSTEM CURRENTLY MOVING
INLAND ALONG THE WEST COAST...THE CENTER OF THE 533DM LOW SPINNING
IN THE PACIFIC WEST OF BRITISH COLUMBIA...THE SOUTHERN EXTENT OF THE
TROUGH IMPACTING CENTRAL AND NORTHERN CALIFORNIA. FURTHER SOUTH AND
AHEAD OF THE TROUGH...BANDS OF HIGH CLOUDS ARE STREAMING ACROSS
SOUTHEAST CALIFORNIA INTO NEVADA AND WESTERN ARIZONA THIS MORNING.
MID AND LOWER LEVEL PRESSURE GRADIENTS CONTINUE TO TIGHTEN...AND THE
LOW LEVEL WIND FIELDS ARE BEGINNING TO RESPOND THROUGH PORTIONS OF
THE SIERRA NEVADA IN CALIFORNIA WITH SOME GUSTS UP TO 30 MPH NOTED
IN SURFACE OBSERVATIONS.

THE INFLUENCE OF THE TROUGH WILL BE FELT ACROSS OUR CWA LATER THIS
AFTERNOON AND EVENING...WITH STRONG GUSTY WINDS OF 20-25 MPH AND
LOCAL GUSTS TO 35 MPH COMMON ACROSS SOUTHEAST CALIFORNIA AND
SOUTHWEST ARIZONA. SOME LOCATIONS IN AND AROUND THE IMPERIAL
VALLEY/EL CENTRO CA...JOSHUA TREE NATIONAL PARK...AND OTHER HIGHER
TERRAIN AREAS IN LA PAZ COUNTY AZ MAY EXPERIENCE STRONGER WIND GUSTS
ALONG WITH AREAS OF BLOWING DUST/SAND. RIGHT NOW...FORECAST WIND
SPEEDS ARE NOT MEETING WIND ADVISORY CRITERIA...BUT IT WILL BE
SOMETHING TO MONITOR.

GIVEN THE DRY NATURE OF THE TROUGH AND FRONTAL PASSAGE...THE WINDS
WILL ONLY CONTRIBUTE TO DANGEROUS FIRE WEATHER CONDITIONS. AS
SUCH...A RED FLAG WARNING IS IN EFFECT FROM 2 TO 8 PM TODAY FOR
SOUTHWEST ARIZONA INCLUDING THE LOWER COLORADO RIVER VALLEY. THE
SYSTEM WILL ALSO BRING 8-10 DEGREES OF COOLING...LOWERING DAYTIME
TEMPERATURES BACK INTO THE MID TO UPPER 80S OVER THE LOWER DESERTS.

SHORTWAVE RIDGING COMMENCES THURSDAY...WITH 500MB HEIGHTS REBOUNDING
TO NEAR 576DM OVER SOUTHERN CALIFORNIA AND SOUTH-CENTRAL ARIZONA BY
FRIDAY. HOWEVER...ANOTHER POTENT UPPER LEVEL TROUGH WILL MOVE INTO
THE REGION LATE FRIDAY AND ONCE AGAIN BRING ANOTHER ROUND OF COOLER
TEMPERATURES AND INCREASED WINDS THIS WEEKEND.

THE GFS/ECMWF ARE NOW IN MUCH BETTER AGREEMENT WITH THIS NEXT
SYSTEM...EVEN THOUGH THERE ARE STILL SOME TIMING DIFFERENCES. BOTH
PLACE A 542-556DM UPPER LEVEL LOW/OPEN WAVE OVER NEVADA BY SATURDAY
MORNING. THE OPERATIONAL GEM MORE ALIGNED WITH THE GFS AND ECMWF...
BUT MAINTAINING A CLOSED LOW SOLUTION. AT THIS TIME...UNLESS THE
SYSTEM DIGS EVEN DEEPER WEST OF CALIFORNIA...ANY SOLUTION WILL
REMAIN CONSIDERABLY DRY WITH PRECIPITATION CHANCES SLIGHT/SLIM FOR
OUR FORECAST AREA. WITH LOWER HEIGHTS AND A TIGHTENED GRADIENT OF
555-564DM SPLAYED ACROSS SOUTHEAST CALIFORNIA AND SOUTH-CENTRAL
ARIZONA...THE FORECAST WILL CONTINUE TO DROP DAYTIME TEMPERATURES
BACK INTO THE LOW 80S...ALONG WITH BREEZY TO WINDY CONDITIONS AGAIN
SATURDAY AND SUNDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
WINDS WILL BE THE MAIN AVIATION CONCERN THROUGH WEDNESDAY
MORNING...WITH INCREASING SPEEDS AND FREQUENT GUSTS DEVELOPING THIS
AFTERNOON THROUGH EARLY EVENING. THE LARGEST PROBLEM MAY BE A
PROLONGED SEVERAL HOUR PERIOD OF A SOUTHERLY CROSS COMPONENT LATE
MORNING/EARLY AFTERNOON. ANY GUSTS ASSOCIATED WITH A DUE SOUTH WIND
SHOULD REMAIN AOB 20KT...BEFORE THE DIRECTION VEERS TOWARDS A MORE
SWLY/WLY DIRECTION LATER IN THE AFTERNOON. GUSTS SHOULD SUBSIDE
LATER THIS EVENING...HOWEVER FORECAST CONFIDENCE IN TIMING THE LOSS
OF GUSTINESS IS LOW.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
STRONG SFC WINDS WILL BE THE LARGEST AVIATION CONCERN ACROSS SE
CALIFORNIA THIS AFTERNOON AND EVENING. A WLY COMPONENT AT KIPL AND
SLY WIND AT KBLH WILL BOTH BEGIN GUSTING ABOVE 20KT BY LATE MORNING.
EVENTUALLY WINDS AT BOTH AIRFIELDS WILL BECOMING SWLY BY LATE
AFTERNOON WITH FREQUENT GUSTS TO AROUND 30KT DEVELOPING. NOCTURNAL
DECOUPLING SHOULD ALLOW GUSTS TO SUBSIDE LATER THIS
EVENING...HOWEVER THE FORECAST CONFIDENCE IN TIMING WHEN WIND SPEEDS
BEGIN TO DECREASE IS LOW.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
WEAK HIGH PRESSURE AND RELATIVELY LIGHT WINDS THURSDAY WILL BE
REPLACED BY A STRONG PACIFIC WEATHER SYSTEM MOVING NORTH OF THE
DISTRICT FRIDAY AND SATURDAY. THIS SYSTEM WILL ALLOW WINDS TO
INCREASE IN A SIMILAR FASHION TO TODAY...YIELDING AN ELEVATED FIRE
DANGER WITH HUMIDITY LEVELS FALLING INTO THE LOWER TEENS AND WIND
GUSTS APPROACHING 30 MPH. MORE TRANQUIL WEATHER CONDITIONS ARE
LIKELY NEXT WEEK WITH A WARMING TREND...ALBEIT WITH MINIMUM HUMIDITY
LEVELS FALLING BACK INTO THE SINGLE DIGITS AND ONLY FAIR OVERNIGHT
RECOVERY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...RED FLAG WARNING TUESDAY AFTERNOON AND EVENING FOR FIRE ZONES
AZZ131 AND AZZ132...2 PM UNTIL 8 PM.

CA...RED FLAG WARNING TUESDAY AFTERNOON AND EVENING FOR FIRE ZONE
CAZ231...2 PM UNTIL 8 PM.

&&

$$

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

DISCUSSION...AJ
PREVIOUS DISCUSSION...MEYERS
AVIATION...MO
FIRE WEATHER...MO








000
FXUS65 KPSR 221156
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
455 AM MST TUE APR 22 2014

...UPDATED AVIATION AND FIRE WEATHER...

.SYNOPSIS...
BREEZY TO WINDY CONDITIONS WILL DEVELOP OVER MUCH OF THE AREA THIS
AFTERNOON INTO WEDNESDAY AS A DRY WEATHER SYSTEM PASSES TO THE
NORTH. TEMPERATURES WILL FALL IN RESPONSE TO THIS WEATHER SYSTEM...
AND LOWER TO AROUND SEASONAL NORMALS BY WEDNESDAY.  A SLIGHT WARMING
TREND WILL OCCUR THURSDAY INTO FRIDAY AS HIGHER PRESSURE ALOFT
RETURNS TO THE AREA...BEFORE ANOTHER VIGOROUS PACIFIC UPPER LEVEL
LOW PRESSURE SYSTEM BRINGS SIGNIFICANT WIND AND COOLING TO THE AREA
OVER THE WEEKEND.

&&

.DISCUSSION...
WATER VAPOR IMAGERY REVEALS OUR NEXT WEATHER SYSTEM CURRENTLY MOVING
INLAND ALONG THE WEST COAST...THE CENTER OF THE 533DM LOW SPINNING
IN THE PACIFIC WEST OF BRITISH COLUMBIA...THE SOUTHERN EXTENT OF THE
TROUGH IMPACTING CENTRAL AND NORTHERN CALIFORNIA. FURTHER SOUTH AND
AHEAD OF THE TROUGH...BANDS OF HIGH CLOUDS ARE STREAMING ACROSS
SOUTHEAST CALIFORNIA INTO NEVADA AND WESTERN ARIZONA THIS MORNING.
MID AND LOWER LEVEL PRESSURE GRADIENTS CONTINUE TO TIGHTEN...AND THE
LOW LEVEL WIND FIELDS ARE BEGINNING TO RESPOND THROUGH PORTIONS OF
THE SIERRA NEVADA IN CALIFORNIA WITH SOME GUSTS UP TO 30 MPH NOTED
IN SURFACE OBSERVATIONS.

THE INFLUENCE OF THE TROUGH WILL BE FELT ACROSS OUR CWA LATER THIS
AFTERNOON AND EVENING...WITH STRONG GUSTY WINDS OF 20-25 MPH AND
LOCAL GUSTS TO 35 MPH COMMON ACROSS SOUTHEAST CALIFORNIA AND
SOUTHWEST ARIZONA. SOME LOCATIONS IN AND AROUND THE IMPERIAL
VALLEY/EL CENTRO CA...JOSHUA TREE NATIONAL PARK...AND OTHER HIGHER
TERRAIN AREAS IN LA PAZ COUNTY AZ MAY EXPERIENCE STRONGER WIND GUSTS
ALONG WITH AREAS OF BLOWING DUST/SAND. RIGHT NOW...FORECAST WIND
SPEEDS ARE NOT MEETING WIND ADVISORY CRITERIA...BUT IT WILL BE
SOMETHING TO MONITOR.

GIVEN THE DRY NATURE OF THE TROUGH AND FRONTAL PASSAGE...THE WINDS
WILL ONLY CONTRIBUTE TO DANGEROUS FIRE WEATHER CONDITIONS. AS
SUCH...A RED FLAG WARNING IS IN EFFECT FROM 2 TO 8 PM TODAY FOR
SOUTHWEST ARIZONA INCLUDING THE LOWER COLORADO RIVER VALLEY. THE
SYSTEM WILL ALSO BRING 8-10 DEGREES OF COOLING...LOWERING DAYTIME
TEMPERATURES BACK INTO THE MID TO UPPER 80S OVER THE LOWER DESERTS.

SHORTWAVE RIDGING COMMENCES THURSDAY...WITH 500MB HEIGHTS REBOUNDING
TO NEAR 576DM OVER SOUTHERN CALIFORNIA AND SOUTH-CENTRAL ARIZONA BY
FRIDAY. HOWEVER...ANOTHER POTENT UPPER LEVEL TROUGH WILL MOVE INTO
THE REGION LATE FRIDAY AND ONCE AGAIN BRING ANOTHER ROUND OF COOLER
TEMPERATURES AND INCREASED WINDS THIS WEEKEND.

THE GFS/ECMWF ARE NOW IN MUCH BETTER AGREEMENT WITH THIS NEXT
SYSTEM...EVEN THOUGH THERE ARE STILL SOME TIMING DIFFERENCES. BOTH
PLACE A 542-556DM UPPER LEVEL LOW/OPEN WAVE OVER NEVADA BY SATURDAY
MORNING. THE OPERATIONAL GEM MORE ALIGNED WITH THE GFS AND ECMWF...
BUT MAINTAINING A CLOSED LOW SOLUTION. AT THIS TIME...UNLESS THE
SYSTEM DIGS EVEN DEEPER WEST OF CALIFORNIA...ANY SOLUTION WILL
REMAIN CONSIDERABLY DRY WITH PRECIPITATION CHANCES SLIGHT/SLIM FOR
OUR FORECAST AREA. WITH LOWER HEIGHTS AND A TIGHTENED GRADIENT OF
555-564DM SPLAYED ACROSS SOUTHEAST CALIFORNIA AND SOUTH-CENTRAL
ARIZONA...THE FORECAST WILL CONTINUE TO DROP DAYTIME TEMPERATURES
BACK INTO THE LOW 80S...ALONG WITH BREEZY TO WINDY CONDITIONS AGAIN
SATURDAY AND SUNDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
WINDS WILL BE THE MAIN AVIATION CONCERN THROUGH WEDNESDAY
MORNING...WITH INCREASING SPEEDS AND FREQUENT GUSTS DEVELOPING THIS
AFTERNOON THROUGH EARLY EVENING. THE LARGEST PROBLEM MAY BE A
PROLONGED SEVERAL HOUR PERIOD OF A SOUTHERLY CROSS COMPONENT LATE
MORNING/EARLY AFTERNOON. ANY GUSTS ASSOCIATED WITH A DUE SOUTH WIND
SHOULD REMAIN AOB 20KT...BEFORE THE DIRECTION VEERS TOWARDS A MORE
SWLY/WLY DIRECTION LATER IN THE AFTERNOON. GUSTS SHOULD SUBSIDE
LATER THIS EVENING...HOWEVER FORECAST CONFIDENCE IN TIMING THE LOSS
OF GUSTINESS IS LOW.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
STRONG SFC WINDS WILL BE THE LARGEST AVIATION CONCERN ACROSS SE
CALIFORNIA THIS AFTERNOON AND EVENING. A WLY COMPONENT AT KIPL AND
SLY WIND AT KBLH WILL BOTH BEGIN GUSTING ABOVE 20KT BY LATE MORNING.
EVENTUALLY WINDS AT BOTH AIRFIELDS WILL BECOMING SWLY BY LATE
AFTERNOON WITH FREQUENT GUSTS TO AROUND 30KT DEVELOPING. NOCTURNAL
DECOUPLING SHOULD ALLOW GUSTS TO SUBSIDE LATER THIS
EVENING...HOWEVER THE FORECAST CONFIDENCE IN TIMING WHEN WIND SPEEDS
BEGIN TO DECREASE IS LOW.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
WEAK HIGH PRESSURE AND RELATIVELY LIGHT WINDS THURSDAY WILL BE
REPLACED BY A STRONG PACIFIC WEATHER SYSTEM MOVING NORTH OF THE
DISTRICT FRIDAY AND SATURDAY. THIS SYSTEM WILL ALLOW WINDS TO
INCREASE IN A SIMILAR FASHION TO TODAY...YIELDING AN ELEVATED FIRE
DANGER WITH HUMIDITY LEVELS FALLING INTO THE LOWER TEENS AND WIND
GUSTS APPROACHING 30 MPH. MORE TRANQUIL WEATHER CONDITIONS ARE
LIKELY NEXT WEEK WITH A WARMING TREND...ALBEIT WITH MINIMUM HUMIDITY
LEVELS FALLING BACK INTO THE SINGLE DIGITS AND ONLY FAIR OVERNIGHT
RECOVERY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...RED FLAG WARNING TUESDAY AFTERNOON AND EVENING FOR FIRE ZONES
AZZ131 AND AZZ132...2 PM UNTIL 8 PM.

CA...RED FLAG WARNING TUESDAY AFTERNOON AND EVENING FOR FIRE ZONE
CAZ231...2 PM UNTIL 8 PM.

&&

$$

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

DISCUSSION...MEYERS
AVIATION...MO
FIRE WEATHER...MO







000
FXUS65 KPSR 221156
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
455 AM MST TUE APR 22 2014

...UPDATED AVIATION AND FIRE WEATHER...

.SYNOPSIS...
BREEZY TO WINDY CONDITIONS WILL DEVELOP OVER MUCH OF THE AREA THIS
AFTERNOON INTO WEDNESDAY AS A DRY WEATHER SYSTEM PASSES TO THE
NORTH. TEMPERATURES WILL FALL IN RESPONSE TO THIS WEATHER SYSTEM...
AND LOWER TO AROUND SEASONAL NORMALS BY WEDNESDAY.  A SLIGHT WARMING
TREND WILL OCCUR THURSDAY INTO FRIDAY AS HIGHER PRESSURE ALOFT
RETURNS TO THE AREA...BEFORE ANOTHER VIGOROUS PACIFIC UPPER LEVEL
LOW PRESSURE SYSTEM BRINGS SIGNIFICANT WIND AND COOLING TO THE AREA
OVER THE WEEKEND.

&&

.DISCUSSION...
WATER VAPOR IMAGERY REVEALS OUR NEXT WEATHER SYSTEM CURRENTLY MOVING
INLAND ALONG THE WEST COAST...THE CENTER OF THE 533DM LOW SPINNING
IN THE PACIFIC WEST OF BRITISH COLUMBIA...THE SOUTHERN EXTENT OF THE
TROUGH IMPACTING CENTRAL AND NORTHERN CALIFORNIA. FURTHER SOUTH AND
AHEAD OF THE TROUGH...BANDS OF HIGH CLOUDS ARE STREAMING ACROSS
SOUTHEAST CALIFORNIA INTO NEVADA AND WESTERN ARIZONA THIS MORNING.
MID AND LOWER LEVEL PRESSURE GRADIENTS CONTINUE TO TIGHTEN...AND THE
LOW LEVEL WIND FIELDS ARE BEGINNING TO RESPOND THROUGH PORTIONS OF
THE SIERRA NEVADA IN CALIFORNIA WITH SOME GUSTS UP TO 30 MPH NOTED
IN SURFACE OBSERVATIONS.

THE INFLUENCE OF THE TROUGH WILL BE FELT ACROSS OUR CWA LATER THIS
AFTERNOON AND EVENING...WITH STRONG GUSTY WINDS OF 20-25 MPH AND
LOCAL GUSTS TO 35 MPH COMMON ACROSS SOUTHEAST CALIFORNIA AND
SOUTHWEST ARIZONA. SOME LOCATIONS IN AND AROUND THE IMPERIAL
VALLEY/EL CENTRO CA...JOSHUA TREE NATIONAL PARK...AND OTHER HIGHER
TERRAIN AREAS IN LA PAZ COUNTY AZ MAY EXPERIENCE STRONGER WIND GUSTS
ALONG WITH AREAS OF BLOWING DUST/SAND. RIGHT NOW...FORECAST WIND
SPEEDS ARE NOT MEETING WIND ADVISORY CRITERIA...BUT IT WILL BE
SOMETHING TO MONITOR.

GIVEN THE DRY NATURE OF THE TROUGH AND FRONTAL PASSAGE...THE WINDS
WILL ONLY CONTRIBUTE TO DANGEROUS FIRE WEATHER CONDITIONS. AS
SUCH...A RED FLAG WARNING IS IN EFFECT FROM 2 TO 8 PM TODAY FOR
SOUTHWEST ARIZONA INCLUDING THE LOWER COLORADO RIVER VALLEY. THE
SYSTEM WILL ALSO BRING 8-10 DEGREES OF COOLING...LOWERING DAYTIME
TEMPERATURES BACK INTO THE MID TO UPPER 80S OVER THE LOWER DESERTS.

SHORTWAVE RIDGING COMMENCES THURSDAY...WITH 500MB HEIGHTS REBOUNDING
TO NEAR 576DM OVER SOUTHERN CALIFORNIA AND SOUTH-CENTRAL ARIZONA BY
FRIDAY. HOWEVER...ANOTHER POTENT UPPER LEVEL TROUGH WILL MOVE INTO
THE REGION LATE FRIDAY AND ONCE AGAIN BRING ANOTHER ROUND OF COOLER
TEMPERATURES AND INCREASED WINDS THIS WEEKEND.

THE GFS/ECMWF ARE NOW IN MUCH BETTER AGREEMENT WITH THIS NEXT
SYSTEM...EVEN THOUGH THERE ARE STILL SOME TIMING DIFFERENCES. BOTH
PLACE A 542-556DM UPPER LEVEL LOW/OPEN WAVE OVER NEVADA BY SATURDAY
MORNING. THE OPERATIONAL GEM MORE ALIGNED WITH THE GFS AND ECMWF...
BUT MAINTAINING A CLOSED LOW SOLUTION. AT THIS TIME...UNLESS THE
SYSTEM DIGS EVEN DEEPER WEST OF CALIFORNIA...ANY SOLUTION WILL
REMAIN CONSIDERABLY DRY WITH PRECIPITATION CHANCES SLIGHT/SLIM FOR
OUR FORECAST AREA. WITH LOWER HEIGHTS AND A TIGHTENED GRADIENT OF
555-564DM SPLAYED ACROSS SOUTHEAST CALIFORNIA AND SOUTH-CENTRAL
ARIZONA...THE FORECAST WILL CONTINUE TO DROP DAYTIME TEMPERATURES
BACK INTO THE LOW 80S...ALONG WITH BREEZY TO WINDY CONDITIONS AGAIN
SATURDAY AND SUNDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
WINDS WILL BE THE MAIN AVIATION CONCERN THROUGH WEDNESDAY
MORNING...WITH INCREASING SPEEDS AND FREQUENT GUSTS DEVELOPING THIS
AFTERNOON THROUGH EARLY EVENING. THE LARGEST PROBLEM MAY BE A
PROLONGED SEVERAL HOUR PERIOD OF A SOUTHERLY CROSS COMPONENT LATE
MORNING/EARLY AFTERNOON. ANY GUSTS ASSOCIATED WITH A DUE SOUTH WIND
SHOULD REMAIN AOB 20KT...BEFORE THE DIRECTION VEERS TOWARDS A MORE
SWLY/WLY DIRECTION LATER IN THE AFTERNOON. GUSTS SHOULD SUBSIDE
LATER THIS EVENING...HOWEVER FORECAST CONFIDENCE IN TIMING THE LOSS
OF GUSTINESS IS LOW.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
STRONG SFC WINDS WILL BE THE LARGEST AVIATION CONCERN ACROSS SE
CALIFORNIA THIS AFTERNOON AND EVENING. A WLY COMPONENT AT KIPL AND
SLY WIND AT KBLH WILL BOTH BEGIN GUSTING ABOVE 20KT BY LATE MORNING.
EVENTUALLY WINDS AT BOTH AIRFIELDS WILL BECOMING SWLY BY LATE
AFTERNOON WITH FREQUENT GUSTS TO AROUND 30KT DEVELOPING. NOCTURNAL
DECOUPLING SHOULD ALLOW GUSTS TO SUBSIDE LATER THIS
EVENING...HOWEVER THE FORECAST CONFIDENCE IN TIMING WHEN WIND SPEEDS
BEGIN TO DECREASE IS LOW.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
WEAK HIGH PRESSURE AND RELATIVELY LIGHT WINDS THURSDAY WILL BE
REPLACED BY A STRONG PACIFIC WEATHER SYSTEM MOVING NORTH OF THE
DISTRICT FRIDAY AND SATURDAY. THIS SYSTEM WILL ALLOW WINDS TO
INCREASE IN A SIMILAR FASHION TO TODAY...YIELDING AN ELEVATED FIRE
DANGER WITH HUMIDITY LEVELS FALLING INTO THE LOWER TEENS AND WIND
GUSTS APPROACHING 30 MPH. MORE TRANQUIL WEATHER CONDITIONS ARE
LIKELY NEXT WEEK WITH A WARMING TREND...ALBEIT WITH MINIMUM HUMIDITY
LEVELS FALLING BACK INTO THE SINGLE DIGITS AND ONLY FAIR OVERNIGHT
RECOVERY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...RED FLAG WARNING TUESDAY AFTERNOON AND EVENING FOR FIRE ZONES
AZZ131 AND AZZ132...2 PM UNTIL 8 PM.

CA...RED FLAG WARNING TUESDAY AFTERNOON AND EVENING FOR FIRE ZONE
CAZ231...2 PM UNTIL 8 PM.

&&

$$

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

DISCUSSION...MEYERS
AVIATION...MO
FIRE WEATHER...MO








000
FXUS65 KPSR 221032
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
325 AM MST TUE APR 22 2014

.SYNOPSIS...
BREEZY TO WINDY CONDITIONS WILL DEVELOP OVER MUCH OF THE AREA THIS
AFTERNOON INTO WEDNESDAY AS A DRY WEATHER SYSTEM PASSES TO THE
NORTH. TEMPERATURES WILL FALL IN RESPONSE TO THIS WEATHER SYSTEM...
AND LOWER TO AROUND SEASONAL NORMALS BY WEDNESDAY.  A SLIGHT WARMING
TREND WILL OCCUR THURSDAY INTO FRIDAY AS HIGHER PRESSURE ALOFT
RETURNS TO THE AREA...BEFORE ANOTHER VIGOROUS PACIFIC UPPER LEVEL
LOW PRESSURE SYSTEM BRINGS SIGNIFICANT WIND AND COOLING TO THE AREA
OVER THE WEEKEND.

&&

.DISCUSSION...
WATER VAPOR IMAGERY REVEALS OUR NEXT WEATHER SYSTEM CURRENTLY MOVING
INLAND ALONG THE WEST COAST...THE CENTER OF THE 533DM LOW SPINNING
IN THE PACIFIC WEST OF BRITISH COLUMBIA...THE SOUTHERN EXTENT OF THE
TROUGH IMPACTING CENTRAL AND NORTHERN CALIFORNIA. FURTHER SOUTH AND
AHEAD OF THE TROUGH...BANDS OF HIGH CLOUDS ARE STREAMING ACROSS
SOUTHEAST CALIFORNIA INTO NEVADA AND WESTERN ARIZONA THIS MORNING.
MID AND LOWER LEVEL PRESSURE GRADIENTS CONTINUE TO TIGHTEN...AND THE
LOW LEVEL WIND FIELDS ARE BEGINNING TO RESPOND THROUGH PORTIONS OF
THE SIERRA NEVADA IN CALIFORNIA WITH SOME GUSTS UP TO 30 MPH NOTED
IN SURFACE OBSERVATIONS.

THE INFLUENCE OF THE TROUGH WILL BE FELT ACROSS OUR CWA LATER THIS
AFTERNOON AND EVENING...WITH STRONG GUSTY WINDS OF 20-25 MPH AND
LOCAL GUSTS TO 35 MPH COMMON ACROSS SOUTHEAST CALIFORNIA AND
SOUTHWEST ARIZONA. SOME LOCATIONS IN AND AROUND THE IMPERIAL
VALLEY/EL CENTRO CA...JOSHUA TREE NATIONAL PARK...AND OTHER HIGHER
TERRAIN AREAS IN LA PAZ COUNTY AZ MAY EXPERIENCE STRONGER WIND GUSTS
ALONG WITH AREAS OF BLOWING DUST/SAND. RIGHT NOW...FORECAST WIND
SPEEDS ARE NOT MEETING WIND ADVISORY CRITERIA...BUT IT WILL BE
SOMETHING TO MONITOR.

GIVEN THE DRY NATURE OF THE TROUGH AND FRONTAL PASSAGE...THE WINDS
WILL ONLY CONTRIBUTE TO DANGEROUS FIRE WEATHER CONDITIONS. AS
SUCH...A RED FLAG WARNING IS IN EFFECT FROM 2 TO 8 PM TODAY FOR
SOUTHWEST ARIZONA INCLUDING THE LOWER COLORADO RIVER VALLEY. THE
SYSTEM WILL ALSO BRING 8-10 DEGREES OF COOLING...LOWERING DAYTIME
TEMPERATURES BACK INTO THE MID TO UPPER 80S OVER THE LOWER DESERTS.

SHORTWAVE RIDGING COMMENCES THURSDAY...WITH 500MB HEIGHTS REBOUNDING
TO NEAR 576DM OVER SOUTHERN CALIFORNIA AND SOUTH-CENTRAL ARIZONA BY
FRIDAY. HOWEVER...ANOTHER POTENT UPPER LEVEL TROUGH WILL MOVE INTO
THE REGION LATE FRIDAY AND ONCE AGAIN BRING ANOTHER ROUND OF COOLER
TEMPERATURES AND INCREASED WINDS THIS WEEKEND.

THE GFS/ECMWF ARE NOW IN MUCH BETTER AGREEMENT WITH THIS NEXT
SYSTEM...EVEN THOUGH THERE ARE STILL SOME TIMING DIFFERENCES. BOTH
PLACE A 542-556DM UPPER LEVEL LOW/OPEN WAVE OVER NEVADA BY SATURDAY
MORNING. THE OPERATIONAL GEM MORE ALIGNED WITH THE GFS AND ECMWF...
BUT MAINTAINING A CLOSED LOW SOLUTION. AT THIS TIME...UNLESS THE
SYSTEM DIGS EVEN DEEPER WEST OF CALIFORNIA...ANY SOLUTION WILL
REMAIN CONSIDERABLY DRY WITH PRECIPITATION CHANCES SLIGHT/SLIM FOR
OUR FORECAST AREA. WITH LOWER HEIGHTS AND A TIGHTENED GRADIENT OF
555-564DM SPLAYED ACROSS SOUTHEAST CALIFORNIA AND SOUTH-CENTRAL
ARIZONA...THE FORECAST WILL CONTINUE TO DROP DAYTIME TEMPERATURES
BACK INTO THE LOW 80S...ALONG WITH BREEZY TO WINDY CONDITIONS AGAIN
SATURDAY AND SUNDAY.

&&

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

SKIES TO REMAIN MOSTLY CLEAR TONIGHT...WITH THIN HIGH LEVEL CIRRUS
SLOWLY MOVING INTO THE AREA FROM THE WEST. OVERNIGHT WINDS ACROSS
SOUTHEAST CA...INCLUDING KIPL AND KBLH WILL HOLD S/SW HEADINGS
OVERNIGHT WITH SPEEDS GENERALLY 10KTS OR LESS. PHX AREA TERMINALS TO
SEE LIGHT AND VRB BEFORE TRANSITIONING TO E/SE NEAR OR AFTER 22/10Z.
FOR TUESDAY AFTERNOON...WESTERLY WINDS WILL BECOME BREEZY TO WINDY
AT TIMES...ESPECIALLY ACROSS SOUTHEAST CA AND SOUTHWEST AZ WITH
GUSTS APPROACHING 30KTS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
WEAK HIGH PRESSURE WILL DOMINATE FOR THE LATER PART OF THE
WEEK...WITH LIGHT WINDS THURSDAY AND BREEZY CONDITIONS FRIDAY
AFTERNOON. DRY AND SLIGHTLY ABOVE NORMAL TEMPERATURES ARE EXPECTED
BOTH THURSDAY AND FRIDAY. A STRONG PACIFIC LOW PRESSURE SYSTEM WILL
PROPAGATE INTO THE REGION FRIDAY NIGHT THROUGH SUNDAY ALLOWING WINDS
TO STRENGTHEN AND CREATING ELEVATED FIRE DANGER. MINIMUM HUMIDITIES
WILL GENERALLY BE IN THE TEENS THIS WEEKEND INTO MONDAY AND
TEMPERATURES WILL FALL TO BELOW NORMAL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...RED FLAG WARNING TUESDAY AFTERNOON AND EVENING FOR FIRE ZONES
AZZ131 AND AZZ132...2 PM UNTIL 8 PM.

CA...RED FLAG WARNING TUESDAY AFTERNOON AND EVENING FOR FIRE ZONE
CAZ231...2 PM UNTIL 8 PM.

&&

$$

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

DISCUSSION...MEYERS
AVIATION...NOLTE/CB
FIRE WEATHER...CB






000
FXUS65 KPSR 221032
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
325 AM MST TUE APR 22 2014

.SYNOPSIS...
BREEZY TO WINDY CONDITIONS WILL DEVELOP OVER MUCH OF THE AREA THIS
AFTERNOON INTO WEDNESDAY AS A DRY WEATHER SYSTEM PASSES TO THE
NORTH. TEMPERATURES WILL FALL IN RESPONSE TO THIS WEATHER SYSTEM...
AND LOWER TO AROUND SEASONAL NORMALS BY WEDNESDAY.  A SLIGHT WARMING
TREND WILL OCCUR THURSDAY INTO FRIDAY AS HIGHER PRESSURE ALOFT
RETURNS TO THE AREA...BEFORE ANOTHER VIGOROUS PACIFIC UPPER LEVEL
LOW PRESSURE SYSTEM BRINGS SIGNIFICANT WIND AND COOLING TO THE AREA
OVER THE WEEKEND.

&&

.DISCUSSION...
WATER VAPOR IMAGERY REVEALS OUR NEXT WEATHER SYSTEM CURRENTLY MOVING
INLAND ALONG THE WEST COAST...THE CENTER OF THE 533DM LOW SPINNING
IN THE PACIFIC WEST OF BRITISH COLUMBIA...THE SOUTHERN EXTENT OF THE
TROUGH IMPACTING CENTRAL AND NORTHERN CALIFORNIA. FURTHER SOUTH AND
AHEAD OF THE TROUGH...BANDS OF HIGH CLOUDS ARE STREAMING ACROSS
SOUTHEAST CALIFORNIA INTO NEVADA AND WESTERN ARIZONA THIS MORNING.
MID AND LOWER LEVEL PRESSURE GRADIENTS CONTINUE TO TIGHTEN...AND THE
LOW LEVEL WIND FIELDS ARE BEGINNING TO RESPOND THROUGH PORTIONS OF
THE SIERRA NEVADA IN CALIFORNIA WITH SOME GUSTS UP TO 30 MPH NOTED
IN SURFACE OBSERVATIONS.

THE INFLUENCE OF THE TROUGH WILL BE FELT ACROSS OUR CWA LATER THIS
AFTERNOON AND EVENING...WITH STRONG GUSTY WINDS OF 20-25 MPH AND
LOCAL GUSTS TO 35 MPH COMMON ACROSS SOUTHEAST CALIFORNIA AND
SOUTHWEST ARIZONA. SOME LOCATIONS IN AND AROUND THE IMPERIAL
VALLEY/EL CENTRO CA...JOSHUA TREE NATIONAL PARK...AND OTHER HIGHER
TERRAIN AREAS IN LA PAZ COUNTY AZ MAY EXPERIENCE STRONGER WIND GUSTS
ALONG WITH AREAS OF BLOWING DUST/SAND. RIGHT NOW...FORECAST WIND
SPEEDS ARE NOT MEETING WIND ADVISORY CRITERIA...BUT IT WILL BE
SOMETHING TO MONITOR.

GIVEN THE DRY NATURE OF THE TROUGH AND FRONTAL PASSAGE...THE WINDS
WILL ONLY CONTRIBUTE TO DANGEROUS FIRE WEATHER CONDITIONS. AS
SUCH...A RED FLAG WARNING IS IN EFFECT FROM 2 TO 8 PM TODAY FOR
SOUTHWEST ARIZONA INCLUDING THE LOWER COLORADO RIVER VALLEY. THE
SYSTEM WILL ALSO BRING 8-10 DEGREES OF COOLING...LOWERING DAYTIME
TEMPERATURES BACK INTO THE MID TO UPPER 80S OVER THE LOWER DESERTS.

SHORTWAVE RIDGING COMMENCES THURSDAY...WITH 500MB HEIGHTS REBOUNDING
TO NEAR 576DM OVER SOUTHERN CALIFORNIA AND SOUTH-CENTRAL ARIZONA BY
FRIDAY. HOWEVER...ANOTHER POTENT UPPER LEVEL TROUGH WILL MOVE INTO
THE REGION LATE FRIDAY AND ONCE AGAIN BRING ANOTHER ROUND OF COOLER
TEMPERATURES AND INCREASED WINDS THIS WEEKEND.

THE GFS/ECMWF ARE NOW IN MUCH BETTER AGREEMENT WITH THIS NEXT
SYSTEM...EVEN THOUGH THERE ARE STILL SOME TIMING DIFFERENCES. BOTH
PLACE A 542-556DM UPPER LEVEL LOW/OPEN WAVE OVER NEVADA BY SATURDAY
MORNING. THE OPERATIONAL GEM MORE ALIGNED WITH THE GFS AND ECMWF...
BUT MAINTAINING A CLOSED LOW SOLUTION. AT THIS TIME...UNLESS THE
SYSTEM DIGS EVEN DEEPER WEST OF CALIFORNIA...ANY SOLUTION WILL
REMAIN CONSIDERABLY DRY WITH PRECIPITATION CHANCES SLIGHT/SLIM FOR
OUR FORECAST AREA. WITH LOWER HEIGHTS AND A TIGHTENED GRADIENT OF
555-564DM SPLAYED ACROSS SOUTHEAST CALIFORNIA AND SOUTH-CENTRAL
ARIZONA...THE FORECAST WILL CONTINUE TO DROP DAYTIME TEMPERATURES
BACK INTO THE LOW 80S...ALONG WITH BREEZY TO WINDY CONDITIONS AGAIN
SATURDAY AND SUNDAY.

&&

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

SKIES TO REMAIN MOSTLY CLEAR TONIGHT...WITH THIN HIGH LEVEL CIRRUS
SLOWLY MOVING INTO THE AREA FROM THE WEST. OVERNIGHT WINDS ACROSS
SOUTHEAST CA...INCLUDING KIPL AND KBLH WILL HOLD S/SW HEADINGS
OVERNIGHT WITH SPEEDS GENERALLY 10KTS OR LESS. PHX AREA TERMINALS TO
SEE LIGHT AND VRB BEFORE TRANSITIONING TO E/SE NEAR OR AFTER 22/10Z.
FOR TUESDAY AFTERNOON...WESTERLY WINDS WILL BECOME BREEZY TO WINDY
AT TIMES...ESPECIALLY ACROSS SOUTHEAST CA AND SOUTHWEST AZ WITH
GUSTS APPROACHING 30KTS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
WEAK HIGH PRESSURE WILL DOMINATE FOR THE LATER PART OF THE
WEEK...WITH LIGHT WINDS THURSDAY AND BREEZY CONDITIONS FRIDAY
AFTERNOON. DRY AND SLIGHTLY ABOVE NORMAL TEMPERATURES ARE EXPECTED
BOTH THURSDAY AND FRIDAY. A STRONG PACIFIC LOW PRESSURE SYSTEM WILL
PROPAGATE INTO THE REGION FRIDAY NIGHT THROUGH SUNDAY ALLOWING WINDS
TO STRENGTHEN AND CREATING ELEVATED FIRE DANGER. MINIMUM HUMIDITIES
WILL GENERALLY BE IN THE TEENS THIS WEEKEND INTO MONDAY AND
TEMPERATURES WILL FALL TO BELOW NORMAL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...RED FLAG WARNING TUESDAY AFTERNOON AND EVENING FOR FIRE ZONES
AZZ131 AND AZZ132...2 PM UNTIL 8 PM.

CA...RED FLAG WARNING TUESDAY AFTERNOON AND EVENING FOR FIRE ZONE
CAZ231...2 PM UNTIL 8 PM.

&&

$$

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

DISCUSSION...MEYERS
AVIATION...NOLTE/CB
FIRE WEATHER...CB







000
FXUS65 KPSR 220403
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
902 PM MST MON APR 21 2014

.SYNOPSIS...
BREEZY TO WINDY CONDITIONS WILL DEVELOP OVER MUCH OF THE AREA
TUESDAY AFTERNOON INTO WEDNESDAY AS A DRY WEATHER SYSTEM PASSES TO
THE NORTH. TEMPERATURES WILL FALL IN RESPONSE TO THIS WEATHER
SYSTEM...AND LOWER TO AROUND SEASONAL NORMALS BY WEDNESDAY.  A
SLIGHT WARMING TREND WILL OCCUR THURSDAY INTO FRIDAY AS HIGHER
PRESSURE ALOFT RETURNS TO THE AREA...BEFORE ANOTHER VIGOROUS PACIFIC
UPPER LEVEL LOW PRESSURE SYSTEM BRINGS SIGNIFICANT WIND AND COOLING
TO THE AREA OVER THE WEEKEND.

&&

.DISCUSSION...
TERRAIN DRIVEN CU...PRIMARILY OVER THE MOGOLLON RIM THIS AFTERNOON
WITH VERY ISOLATED DEVELOPMENT OVER GILA COUNTY...HAVE THINNED AND
GRADUALLY DISSIPATED THIS EVENING WITH SUNSET. SOME CLOUDS STILL
LINGER ACROSS THE NORTHEASTERN CORNER OF ARIZONA...AND ADDITIONAL
HIGH CIRRUS BANDS ARE STARTING TO STREAM IN FROM THE WEST AHEAD OF A
WELL DEFINED PACIFIC TROUGH. SFC WINDS WILL INCREASE THROUGH THE
MORNING TUESDAY WITH STRONG AFTERNOON GUSTS EXPECTED OVER MUCH OF
THE FORECAST AREA. CONCERN STILL REMAINS FOR THE DEVELOPMENT OF
CRITICAL FIRE WX CONDITIONS ALONG AND JUST EAST OF THE COLORADO
RIVER AND A RED FLAG WARNING REMAINS IN EFFECT FOR TUESDAY. ANOTHER
WARM AFTERNOON...BUT STILL SHY OF THE 100-DEGREE MARK...IN THE BOOKS
WITH PHOENIX AND YUMA WARMING BOTH TO 98F. DAYTIME TEMPS TUESDAY
EXPECTED TO SEE A FEW DEGREES OF COOLING COMPARED TO THEIR READINGS
TODAY...AND A FEW ADDITIONAL DEGREES ON WEDNESDAY ONCE THE COOL
FRONT/PACIFIC AIRMASS MOVES THROUGH THE AREA. OUTSIDE OF SOME FINE
TUNING OF THE HOURLY GRIDS TO CURRENT TRENDS...NO MAJOR FORECAST
UPDATES NEEDED.

&&

.PREVIOUS DISCUSSION /ISSUED AT 215 PM MST/PDT/...
GUIDANCE REMAINS VERY CONSISTENT IN CALLING FOR THE AFOREMENTIONED
PACIFIC TROF TO PUSH EAST ACROSS THE AREA TUESDAY INTO
WEDNESDAY...BRINGING SIGNIFICANTLY ELEVATED WIND AND DRIER AIR TO
SERN CA AND SRN AZ...BUT NO PRECIP. THIS TYPE OF PATTERN IS VERY
COMMON FOR LATE APRIL. WINDS ON TUESDAY AFTN/EVE ARE EXPECTED TO
STAY BELOW ADVISORY LEVELS BUT GIVEN THE DRY AIR THAT WILL BE IN
PLACE...THEY WILL BE STRONG ENOUGH TO LEAD TO DANGEROUS FIRE WEATHER
CONDITIONS. AS SUCH A RED FLAG WARNING WILL BE ISSUED FOR SOUTHWEST
ARIZONA INCLUDING THE LOWER COLORADO RIVER VALLEY. THE WARNING WILL
COMMENCE AT 2 PM TUESDAY AND RUN THROUGH 8 PM...AND WILL FOCUS ON
DESERT AREAS TO THE WEST OF THE GREATER PHOENIX AREA. THE SYSTEM
WILL ALSO BRING 8-10 DEGREES OF COOLING...LOWERING HIGH TEMPS
WEDNESDAY INTO THE MID TO UPPER 80S OVER THE DESERTS UNDER MOSTLY
SUNNY SKIES.

SHORTWAVE RIDGING COMMENCES THURSDAY...WITH 500MB HEIGHTS REBOUNDING
TO NEAR 576DM OVER SOUTHERN CA AND AZ BY FRIDAY. ENSEMBLE SPREAD
CONTINUES TO GROW FOR THE WEEKEND TIME FRAME WITH EACH FORECAST
ITERATION. THE MODEL TREND OF NEGATIVE HEIGHT ANOMALIES COVERING THE
NORTHEAST PACIFIC BASIN REMAINS CONSISTENT...HOWEVER THE SUBSEQUENT
PROGRESSION OF SHORTWAVES INTO THE WESTERN AND CENTRAL CONUS IS
HIGHLY UNCERTAIN.

OPERATIONAL MEMBERS HAVE RETAINED GOOD RUN TO RUN CONTINUITY...WITH
THE GFS CURRENTLY DEEPENING A 541DM CLOSED LOW INTO THE SOUTHWESTERN
CONUS OVER THE WEEKEND...WHILE THE ECMWF EJECTS SEVERAL WEAKER LEAD
WAVES THROUGH THE DOWNSTREAM QUASI-ZONAL FLOW WHILE MAINTAINING
GENERAL EAST PACIFIC TROUGHING. THE OPERATIONAL GEM IS SOMEWHAT OF A
COMPROMISE OF THESE TWO EXTREMES...BUT IT CONTINUES TO FAVOR SOME
MEASURE OF DEEPER TROUGHING NEAR THE FORECAST AREA.

ENSEMBLE MEMBERS STILL EXHIBIT A VAST ARRAY OF POSSIBLE OUTCOMES...
RESULTING IN A LOWER FORECAST CONFIDENCE FOR THE WEEKEND. AT THIS
TIME...UNLESS THE SYSTEM DIGS EVEN DEEPER WEST OF CALIFORNIA...ANY
SOLUTION WILL BE CONSIDERABLY DRY WITH PRECIPITATION CHANCES
SLIGHT/SLIM FOR OUR FORECAST AREA. THERE IS SOME AGREEMENT AS TO
LOWER HEIGHTS SPLAYED OVER THE REGION...WITH A TIGHTENED GRADIENT
SOMEWHERE IN THE 564DM RANGE STRETCHED ACROSS SOUTHEAST CA AND
SOUTH-CENTRAL AZ. AS SUCH...ELECTED TO DROP FORECAST DAYTIME
TEMPERATURES BACK INTO THE LOW 80S FOR THE WEEKEND...ALONG WITH
BREEZY TO WINDY CONDITIONS AGAIN SATURDAY AND SUNDAY.

&&

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

SKIES TO REMAIN MOSTLY CLEAR TONIGHT...WITH THIN HIGH LEVEL CIRRUS
SLOWLY MOVING INTO THE AREA FROM THE WEST. OVERNIGHT WINDS ACROSS
SOUTHEAST CA...INCLUDING KIPL AND KBLH WILL HOLD S/SW HEADINGS
OVERNIGHT WITH SPEEDS GNLY 10KTS OR LESS. PHX AREA TERMINALS TO SEE
LIGHT AND VRB BEFORE TRANSITIONING TO E/SE NEAR OR AFTER 22/10Z. FOR
TUESDAY AFTERNOON...WESTERLY WINDS WILL BECOME BREEZY TO WINDY AT
TIMES...ESPECIALLY ACROSS SOUTHEAST CA AND SOUTHWEST AZ WITH GUSTS
APPROACHING 30KTS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
WEAK HIGH PRESSURE WILL DOMINATE FOR THE LATER PART OF THE
WEEK...WITH LIGHT WINDS THURSDAY AND BREEZY CONDITIONS FRIDAY
AFTERNOON. DRY AND SLIGHTLY ABOVE NORMAL TEMPERATURES ARE EXPECTED
BOTH THURSDAY AND FRIDAY. A STRONG PACIFIC LOW PRESSURE SYSTEM WILL
PROPAGATE INTO THE REGION FRIDAY NIGHT THROUGH SUNDAY ALLOWING WINDS
TO STRENGTHEN AND CREATING ELEVATED FIRE DANGER. MINIMUM HUMIDITIES
WILL GENERALLY BE IN THE TEENS THIS WEEKEND INTO MONDAY AND
TEMPERATURES WILL FALL TO BELOW NORMAL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...RED FLAG WARNING TUESDAY AFTERNOON AND EVENING FOR FIRE ZONES
AZZ131 AND AZZ132...2 PM UNTIL 8 PM.

CA...RED FLAG WARNING TUESDAY AFTERNOON AND EVENING FOR FIRE ZONE
CAZ231...2 PM UNTIL 8 PM.

&&

$$

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

DISCUSSION...NOLTE
PREVIOUS DISCUSSION...CB/MEYERS/MO
AVIATION...NOLTE/CB
FIRE WEATHER...CB










000
FXUS65 KPSR 212115
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
215 PM MST MON APR 21 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE AREA EARLY THIS WEEK LEADING TO
MOSTLY SUNNY DAYS...CLEAR NIGHTS...AND SHARPLY WARMER AFTERNOON HIGH
TEMPERATURES. BREEZY TO WINDY CONDITIONS WILL DEVELOP OVER MUCH OF
THE AREA TUESDAY AFTERNOON INTO WEDNESDAY AS A DRY WEATHER SYSTEM
PASSES TO THE NORTH. TEMPERATURES WILL FALL IN RESPONSE TO THIS
WEATHER SYSTEM...AND LOWER TO AROUND SEASONAL NORMALS BY WEDNESDAY.
A SLIGHT WARMING TREND WILL OCCUR THURSDAY INTO FRIDAY AS HIGHER
PRESSURE ALOFT RETURNS TO THE AREA...BEFORE ANOTHER VIGOROUS PACIFIC
UPPER LEVEL LOW PRESSURE SYSTEM BRINGS SIGNIFICANT WIND AND COOLING
TO THE AREA OVER THE WEEKEND.

&&

.DISCUSSION...
HIGH PRESSURE ALOFT CONTINUED TO BUILD ACROSS THE DESERT SOUTHWEST
THIS AFTERNOON...AHEAD OF AN APPROACHING PACIFIC UPPER TROF. H5
HEIGHTS ACROSS SRN AZ APPROACHED 582DM THIS MORNING...AND AREA
SOUNDINGS ALL SHOWED ABOUT 5-7F WARMING BELOW 700MB. IR AND VISIBLE
IMAGERY SHOWED SUNNY SKIES ACROSS THE DESERTS...AND WITH THE GOOD
MIXING HIGH TEMPS WERE RUNNING 3-8 DEGREES WARMER THAN 24 HOURS AGO.
DESERT HIGHS THIS AFTERNOON SHOULD MOSTLY FINISH IN THE MID 90S TO
NEAR 100 OVER THE WARMER LOWER DESERT.

GUIDANCE REMAINS VERY CONSISTENT IN CALLING FOR THE AFOREMENTIONED
PACIFIC TROF TO PUSH EAST ACROSS THE AREA TUESDAY INTO
WEDNESDAY...BRINGING SIGNIFICANTLY ELEVATED WIND AND DRIER AIR TO
SERN CA AND SRN AZ...BUT NO PRECIP. THIS TYPE OF PATTERN IS VERY
COMMON FOR LATE APRIL. WINDS ON TUESDAY AFTN/EVE ARE EXPECTED TO
STAY BELOW ADVISORY LEVELS BUT GIVEN THE DRY AIR THAT WILL BE IN
PLACE...THEY WILL BE STRONG ENOUGH TO LEAD TO DANGEROUS FIRE WEATHER
CONDITIONS. AS SUCH A RED FLAG WARNING WILL BE ISSUED FOR SOUTHWEST
ARIZONA INCLUDING THE LOWER COLORADO RIVER VALLEY. THE WARNING WILL
COMMENCE AT 2 PM TUESDAY AND RUN THROUGH 8 PM...AND WILL FOCUS ON
DESERT AREAS TO THE WEST OF THE GREATER PHOENIX AREA. THE SYSTEM
WILL ALSO BRING 8-10 DEGREES OF COOLING...LOWERING HIGH TEMPS
WEDNESDAY INTO THE MID TO UPPER 80S OVER THE DESERTS UNDER MOSTLY
SUNNY SKIES.

SHORTWAVE RIDGING COMMENCES THURSDAY...WITH 500MB HEIGHTS REBOUNDING
TO NEAR 576DM OVER SOUTHERN CA AND AZ BY FRIDAY. ENSEMBLE SPREAD
CONTINUES TO GROW FOR THE WEEKEND TIME FRAME WITH EACH FORECAST
ITERATION. THE MODEL TREND OF NEGATIVE HEIGHT ANOMALIES COVERING THE
NORTHEAST PACIFIC BASIN REMAINS CONSISTENT...HOWEVER THE SUBSEQUENT
PROGRESSION OF SHORTWAVES INTO THE WESTERN AND CENTRAL CONUS IS
HIGHLY UNCERTAIN.

OPERATIONAL MEMBERS HAVE RETAINED GOOD RUN TO RUN CONTINUITY...WITH
THE GFS CURRENTLY DEEPENING A 541DM CLOSED LOW INTO THE SOUTHWESTERN
CONUS OVER THE WEEKEND...WHILE THE ECMWF EJECTS SEVERAL WEAKER LEAD
WAVES THROUGH THE DOWNSTREAM QUASI-ZONAL FLOW WHILE MAINTAINING
GENERAL EAST PACIFIC TROUGHING. THE OPERATIONAL GEM IS SOMEWHAT OF A
COMPROMISE OF THESE TWO EXTREMES...BUT IT CONTINUES TO FAVOR SOME
MEASURE OF DEEPER TROUGHING NEAR THE FORECAST AREA.

ENSEMBLE MEMBERS STILL EXHIBIT A VAST ARRAY OF POSSIBLE OUTCOMES...
RESULTING IN A LOWER FORECAST CONFIDENCE FOR THE WEEKEND. AT THIS
TIME...UNLESS THE SYSTEM DIGS EVEN DEEPER WEST OF CALIFORNIA...ANY
SOLUTION WILL BE CONSIDERABLY DRY WITH PRECIPITATION CHANCES
SLIGHT/SLIM FOR OUR FORECAST AREA. THERE IS SOME AGREEMENT AS TO
LOWER HEIGHTS SPLAYED OVER THE REGION...WITH A TIGHTENED GRADIENT
SOMEWHERE IN THE 564DM RANGE STRETCHED ACROSS SOUTHEAST CA AND
SOUTH-CENTRAL AZ. AS SUCH...ELECTED TO DROP FORECAST DAYTIME
TEMPERATURES BACK INTO THE LOW 80S FOR THE WEEKEND...ALONG WITH
BREEZY TO WINDY CONDITIONS AGAIN SATURDAY AND SUNDAY.

&&

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

NO SIGNIFICANT AVIATION CONCERNS THROUGH TUESDAY MORNING AS MOSTLY
CLEAR SKIES AND LIGHT WINDS WILL PREVAIL ACROSS THE REGION.
CONFIDENCE IS FAIRLY HIGH WESTERLY WINDS WILL PREVAIL THROUGHOUT
MUCH OF THE OVERNIGHT. ACROSS SE CALIFORNIA...A PREVAILING S/SW WIND
SHOULD DEVELOP SOMETIME LATE THIS AFTERNOON INTO THIS EVENING. FOR
TUESDAY AFTERNOON...WESTERLY WINDS WILL BECOME BREEZY TO WINDY AT
TIMES...ESPECIALLY ACROSS SOUTHEAST CALIFORNIA AND SOUTHWEST
ARIZONA.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
WEAK HIGH PRESSURE WILL DOMINATE FOR THE LATER PART OF THE
WEEK...WITH LIGHT WINDS THURSDAY AND BREEZY CONDITIONS FRIDAY
AFTERNOON. DRY AND SLIGHTLY ABOVE NORMAL TEMPERATURES ARE EXPECTED
BOTH THURSDAY AND FRIDAY. A STRONG PACIFIC LOW PRESSURE SYSTEM WILL
PROPAGATE INTO THE REGION FRIDAY NIGHT THROUGH SUNDAY ALLOWING WINDS
TO STRENGTHEN AND CREATING ELEVATED FIRE DANGER. MINIMUM HUMIDITIES
WILL GENERALLY BE IN THE TEENS THIS WEEKEND INTO MONDAY AND
TEMPERATURES WILL FALL TO BELOW NORMAL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...RED FLAG WARNING TUESDAY AFTERNOON AND EVENING FOR FIRE ZONES
AZZ131 AND AZZ132...2 PM UNTIL 8 PM.

CA...RED FLAG WARNING TUESDAY AFTERNOON AND EVENING FOR FIRE ZONE
CAZ231...2 PM UNTIL 8 PM.

&&

$$

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

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






















000
FXUS65 KPSR 212115
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
215 PM MST MON APR 21 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE AREA EARLY THIS WEEK LEADING TO
MOSTLY SUNNY DAYS...CLEAR NIGHTS...AND SHARPLY WARMER AFTERNOON HIGH
TEMPERATURES. BREEZY TO WINDY CONDITIONS WILL DEVELOP OVER MUCH OF
THE AREA TUESDAY AFTERNOON INTO WEDNESDAY AS A DRY WEATHER SYSTEM
PASSES TO THE NORTH. TEMPERATURES WILL FALL IN RESPONSE TO THIS
WEATHER SYSTEM...AND LOWER TO AROUND SEASONAL NORMALS BY WEDNESDAY.
A SLIGHT WARMING TREND WILL OCCUR THURSDAY INTO FRIDAY AS HIGHER
PRESSURE ALOFT RETURNS TO THE AREA...BEFORE ANOTHER VIGOROUS PACIFIC
UPPER LEVEL LOW PRESSURE SYSTEM BRINGS SIGNIFICANT WIND AND COOLING
TO THE AREA OVER THE WEEKEND.

&&

.DISCUSSION...
HIGH PRESSURE ALOFT CONTINUED TO BUILD ACROSS THE DESERT SOUTHWEST
THIS AFTERNOON...AHEAD OF AN APPROACHING PACIFIC UPPER TROF. H5
HEIGHTS ACROSS SRN AZ APPROACHED 582DM THIS MORNING...AND AREA
SOUNDINGS ALL SHOWED ABOUT 5-7F WARMING BELOW 700MB. IR AND VISIBLE
IMAGERY SHOWED SUNNY SKIES ACROSS THE DESERTS...AND WITH THE GOOD
MIXING HIGH TEMPS WERE RUNNING 3-8 DEGREES WARMER THAN 24 HOURS AGO.
DESERT HIGHS THIS AFTERNOON SHOULD MOSTLY FINISH IN THE MID 90S TO
NEAR 100 OVER THE WARMER LOWER DESERT.

GUIDANCE REMAINS VERY CONSISTENT IN CALLING FOR THE AFOREMENTIONED
PACIFIC TROF TO PUSH EAST ACROSS THE AREA TUESDAY INTO
WEDNESDAY...BRINGING SIGNIFICANTLY ELEVATED WIND AND DRIER AIR TO
SERN CA AND SRN AZ...BUT NO PRECIP. THIS TYPE OF PATTERN IS VERY
COMMON FOR LATE APRIL. WINDS ON TUESDAY AFTN/EVE ARE EXPECTED TO
STAY BELOW ADVISORY LEVELS BUT GIVEN THE DRY AIR THAT WILL BE IN
PLACE...THEY WILL BE STRONG ENOUGH TO LEAD TO DANGEROUS FIRE WEATHER
CONDITIONS. AS SUCH A RED FLAG WARNING WILL BE ISSUED FOR SOUTHWEST
ARIZONA INCLUDING THE LOWER COLORADO RIVER VALLEY. THE WARNING WILL
COMMENCE AT 2 PM TUESDAY AND RUN THROUGH 8 PM...AND WILL FOCUS ON
DESERT AREAS TO THE WEST OF THE GREATER PHOENIX AREA. THE SYSTEM
WILL ALSO BRING 8-10 DEGREES OF COOLING...LOWERING HIGH TEMPS
WEDNESDAY INTO THE MID TO UPPER 80S OVER THE DESERTS UNDER MOSTLY
SUNNY SKIES.

SHORTWAVE RIDGING COMMENCES THURSDAY...WITH 500MB HEIGHTS REBOUNDING
TO NEAR 576DM OVER SOUTHERN CA AND AZ BY FRIDAY. ENSEMBLE SPREAD
CONTINUES TO GROW FOR THE WEEKEND TIME FRAME WITH EACH FORECAST
ITERATION. THE MODEL TREND OF NEGATIVE HEIGHT ANOMALIES COVERING THE
NORTHEAST PACIFIC BASIN REMAINS CONSISTENT...HOWEVER THE SUBSEQUENT
PROGRESSION OF SHORTWAVES INTO THE WESTERN AND CENTRAL CONUS IS
HIGHLY UNCERTAIN.

OPERATIONAL MEMBERS HAVE RETAINED GOOD RUN TO RUN CONTINUITY...WITH
THE GFS CURRENTLY DEEPENING A 541DM CLOSED LOW INTO THE SOUTHWESTERN
CONUS OVER THE WEEKEND...WHILE THE ECMWF EJECTS SEVERAL WEAKER LEAD
WAVES THROUGH THE DOWNSTREAM QUASI-ZONAL FLOW WHILE MAINTAINING
GENERAL EAST PACIFIC TROUGHING. THE OPERATIONAL GEM IS SOMEWHAT OF A
COMPROMISE OF THESE TWO EXTREMES...BUT IT CONTINUES TO FAVOR SOME
MEASURE OF DEEPER TROUGHING NEAR THE FORECAST AREA.

ENSEMBLE MEMBERS STILL EXHIBIT A VAST ARRAY OF POSSIBLE OUTCOMES...
RESULTING IN A LOWER FORECAST CONFIDENCE FOR THE WEEKEND. AT THIS
TIME...UNLESS THE SYSTEM DIGS EVEN DEEPER WEST OF CALIFORNIA...ANY
SOLUTION WILL BE CONSIDERABLY DRY WITH PRECIPITATION CHANCES
SLIGHT/SLIM FOR OUR FORECAST AREA. THERE IS SOME AGREEMENT AS TO
LOWER HEIGHTS SPLAYED OVER THE REGION...WITH A TIGHTENED GRADIENT
SOMEWHERE IN THE 564DM RANGE STRETCHED ACROSS SOUTHEAST CA AND
SOUTH-CENTRAL AZ. AS SUCH...ELECTED TO DROP FORECAST DAYTIME
TEMPERATURES BACK INTO THE LOW 80S FOR THE WEEKEND...ALONG WITH
BREEZY TO WINDY CONDITIONS AGAIN SATURDAY AND SUNDAY.

&&

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

NO SIGNIFICANT AVIATION CONCERNS THROUGH TUESDAY MORNING AS MOSTLY
CLEAR SKIES AND LIGHT WINDS WILL PREVAIL ACROSS THE REGION.
CONFIDENCE IS FAIRLY HIGH WESTERLY WINDS WILL PREVAIL THROUGHOUT
MUCH OF THE OVERNIGHT. ACROSS SE CALIFORNIA...A PREVAILING S/SW WIND
SHOULD DEVELOP SOMETIME LATE THIS AFTERNOON INTO THIS EVENING. FOR
TUESDAY AFTERNOON...WESTERLY WINDS WILL BECOME BREEZY TO WINDY AT
TIMES...ESPECIALLY ACROSS SOUTHEAST CALIFORNIA AND SOUTHWEST
ARIZONA.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
WEAK HIGH PRESSURE WILL DOMINATE FOR THE LATER PART OF THE
WEEK...WITH LIGHT WINDS THURSDAY AND BREEZY CONDITIONS FRIDAY
AFTERNOON. DRY AND SLIGHTLY ABOVE NORMAL TEMPERATURES ARE EXPECTED
BOTH THURSDAY AND FRIDAY. A STRONG PACIFIC LOW PRESSURE SYSTEM WILL
PROPAGATE INTO THE REGION FRIDAY NIGHT THROUGH SUNDAY ALLOWING WINDS
TO STRENGTHEN AND CREATING ELEVATED FIRE DANGER. MINIMUM HUMIDITIES
WILL GENERALLY BE IN THE TEENS THIS WEEKEND INTO MONDAY AND
TEMPERATURES WILL FALL TO BELOW NORMAL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...RED FLAG WARNING TUESDAY AFTERNOON AND EVENING FOR FIRE ZONES
AZZ131 AND AZZ132...2 PM UNTIL 8 PM.

CA...RED FLAG WARNING TUESDAY AFTERNOON AND EVENING FOR FIRE ZONE
CAZ231...2 PM UNTIL 8 PM.

&&

$$

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

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





















000
FXUS65 KPSR 211531
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
830 AM MST MON APR 21 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE AREA EARLY THIS WEEK LEADING TO
SUNNY DAYS...CLEAR NIGHTS...AND SHARPLY WARMER AFTERNOON HIGH
TEMPERATURES. BREEZY TO WINDY CONDITIONS WILL DEVELOP OVER MUCH OF
THE AREA TUESDAY AFTERNOON INTO WEDNESDAY AS A DRY WEATHER SYSTEM
PASSES TO THE NORTH. TEMPERATURES WILL FALL ONLY SLIGHT IN RESPONSE
TO THIS WEATHER SYSTEM...CLOSER TO SEASONAL NORMALS FOR THE
REMAINDER OF THE WEEK.

&&

.DISCUSSION...
UPPER LEVEL HIGH PRESSURE RIDGE HAS BUILT INTO THE DESERT SOUTHWEST
WITH H5 HEIGHTS NEARLY 582DM ACROSS THE SRN AZ DESERT. IR IMAGERY
SHOWED SUNNY SKIES ACROSS THE REGION AT 8 AM. AREA SOUNDINGS ALL
INDICATE ABOUT 5F WARMING BELOW 700MB...SO EXPECT HIGH TEMPS TODAY
TO CLIMB ANOTHER SEVERAL DEGREES ONCE THE GOOD MIXING BEGINS IN THE
LATE MORNING TO EARLY AFTN. LOOK FOR THE WARMER DESERTS TO CLIMB
INTO THE MID 90S TO NEAR 100 DEGREES TODAY. CURRENT FORECASTS ARE IN
GOOD SHAPE AND NO UPDATES ARE NEEDED ATTM.

.PREVIOUS DISCUSSION...
WATER VAPOR IMAGERY CLEARLY SHOWS AN EXPANDING ANTICYCLONE OVER
ARIZONA AND PORTIONS OF THE INTERMOUNTAIN WEST...WITH A BROAD
DEEPENING 532DM UPPER LEVEL LOW SPINNING OVER THE GULF OF ALASKA
INTO BRITISH COLUMBIA. REGIONAL UPPER AIR PLOTS OVER THE DESERT
SOUTHWEST HAVE SHOWN AROUND A 70M INCREASE IN 500MB HEIGHTS OVER THE
LAST 24 HOURS OR SO...AND THIS WILL LEAD TO ADDITIONAL WARMING FOR
OUR FORECAST AREA TODAY WITH AFTERNOON TEMPERATURES ACROSS THE LOWER
DESERTS RISING INTO THE MID TO UPPER 90S. WITH THE DRIER NATURE OF
THE ATMOSPHERE AND PLENTY OF SUNSHINE...IT WILL NOT BE OUT OF THE
QUESTION FOR SOME LOCATIONS TO FLIRT WITH THE CENTURY MARK FOR THE
FIRST TIME THIS YEAR.

OPERATIONAL MODELS AND NUMERICAL GUIDANCE ARE STILL IN VERY GOOD
AGREEMENT WITH TRACK OF THE UPPER LEVEL LOW OVER THE GULF OF
ALASKA...DROPPING IT SOUTH ALONG THE WEST COAST AND MOVING AN OPEN
WAVE INLAND INTO THE GREAT BASIN BY TUESDAY MORNING. THE SYSTEM WILL
IMPORT LITTLE IN THE WAY OF MOISTURE...BUT MID AND LOWER LEVEL
PRESSURE GRADIENTS WILL TIGHTEN UP AS THE TROUGH PASSES TO OUR
NORTH...GENERATING BREEZY TO WINDY CONDITIONS ACROSS SOUTHEAST
CALIFORNIA AND SOUTHWEST ARIZONA -- WITH SUSTAINED WINDS 15-25 MPH
AND GUSTS TO 35 MPH COMMON ACROSS OUR WESTERN ZONES TUESDAY
AFTERNOON AND EVENING. SOME LOCATIONS IN AND AROUND THE IMPERIAL
VALLEY/EL CENTRO CA...JOSHUA TREE NATIONAL PARK...AND OTHER HIGHER
TERRAIN AREAS IN LA PAZ COUNTY AZ MAY EXPERIENCE STRONGER WINDS AND
SOME AREAS OF BLOWING DUST/SAND. RIGHT NOW...FORECAST WIND SPEEDS
ARE NOT MEETING WIND ADVISORY CRITERIA...BUT IT WILL BE SOMETHING
FOR FUTURE SHIFTS TO FOLLOW/MONITOR.

THE LOW LEVEL FRONTAL PASSAGE SHOULD CLEAR THE FORECAST AREA BY
WEDNESDAY MORNING...WITH MODEST HEIGHT FALLS AND COOLER AIR HELPING
DROP DAYTIME TEMPS CLOSE TO CLIMATOLOGICAL NORMAL WEDNESDAY
AFTERNOON...MAINLY BACK INTO THE MID TO UPPER 80S OVER THE LOWER
DESERTS. LESS WIND IS EXPECTED WEDNESDAY HOWEVER IT WILL STILL BE ON
THE BREEZY SIDE DURING THE AFTERNOON HOURS.

SHORTWAVE RIDGING COMMENCES THURSDAY...WITH 500MB HEIGHTS REBOUNDING
TO NEAR 576DM OVER SOUTHERN CA AND AZ BY FRIDAY. ENSEMBLE SPREAD
CONTINUES TO GROW FOR THE WEEKEND TIME FRAME WITH EACH FORECAST
ITERATION. THE MODEL TREND OF NEGATIVE HEIGHT ANOMALIES COVERING THE
NORTHEAST PACIFIC BASIN REMAINS CONSISTENT...HOWEVER THE SUBSEQUENT
PROGRESSION OF SHORTWAVES INTO THE WESTERN AND CENTRAL CONUS IS
HIGHLY UNCERTAIN.

OPERATIONAL MEMBERS HAVE RETAINED GOOD RUN TO RUN CONTINUITY...WITH
THE GFS CURRENTLY DEEPENING A 541DM CLOSED LOW INTO THE SOUTHWESTERN
CONUS OVER THE WEEKEND...WHILE THE ECMWF EJECTS SEVERAL WEAKER LEAD
WAVES THROUGH THE DOWNSTREAM QUASI-ZONAL FLOW WHILE MAINTAINING
GENERAL EAST PACIFIC TROUGHING. THE OPERATIONAL GEM IS SOMEWHAT OF A
COMPROMISE OF THESE TWO EXTREMES...BUT IT CONTINUES TO FAVOR SOME
MEASURE OF DEEPER TROUGHING NEAR THE FORECAST AREA.

ENSEMBLE MEMBERS STILL EXHIBIT A VAST ARRAY OF POSSIBLE OUTCOMES...
RESULTING IN A LOWER FORECAST CONFIDENCE FOR THE WEEKEND. AT THIS
TIME...UNLESS THE SYSTEM DIGS EVEN DEEPER WEST OF CALIFORNIA...ANY
SOLUTION WILL BE CONSIDERABLY DRY WITH PRECIPITATION CHANCES
SLIGHT/SLIM FOR OUR FORECAST AREA. THERE IS SOME AGREEMENT AS TO
LOWER HEIGHTS SPLAYED OVER THE REGION...WITH A TIGHTENED GRADIENT
SOMEWHERE IN THE 564DM RANGE STRETCHED ACROSS SOUTHEAST CA AND
SOUTH-CENTRAL AZ. AS SUCH...ELECTED TO DROP FORECAST DAYTIME
TEMPERATURES BACK INTO THE LOW 80S FOR THE WEEKEND...ALONG WITH
BREEZY TO WINDY CONDITIONS AGAIN SATURDAY AND SUNDAY.

&&

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

NO SIGNIFICANT AVIATION CONCERNS THROUGH TUESDAY MORNING AS MOSTLY
CLEAR SKIES AND LIGHT WINDS WILL PREVAIL ACROSS THE REGION. THE
DAILY WESTERLY WIND SHIFT OVER CENTRAL ARIZONA SHOULD TEMPORALLY
OCCUR SIMILARLY TO YESTERDAY (EARLY AFTERNOON)...HOWEVER CONFIDENCE
IS FAIRLY HIGH THAT THE WESTERLY COMPONENT WILL PREVAIL THROUGHOUT
MUCH OF THE OVERNIGHT. ACROSS SE CALIFORNIA...A PREVAILING S/SW WIND
SHOULD DEVELOP THOUGH PRECISE ONSET TIMING IS SLIGHTLY MORE
UNCERTAIN.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
HIGH PRESSURE WILL START BUILDING INTO THE REGION ON
WEDNESDAY...HOWEVER LOCALLY BREEZY CONDITIONS WILL STILL
PERSIST...PARTICULARLY DURING THE EARLY AFTERNOON BEFORE THE
PRESSURE GRADIENT RELAXES BY THE EVENING. ANOTHER STRONG PACIFIC LOW
PRESSURE SYSTEM WILL PROPAGATE INTO THE REGION FRIDAY THROUGH
SUNDAY...ALLOWING WINDS TO STRENGTHEN...AND CREATING ANOTHER PERIOD
OF ELEVATED FIRE DANGER. MINIMUM HUMIDITIES WILL FALL INTO THE
SINGLE DIGITS ACROSS THE LOWER DESERTS THROUGH FRIDAY...BEFORE
SEEING A SLIGHT IMPROVEMENT MAINLY IN THE TEENS OVER THE WEEKEND AS
SOMEWHAT COOLER WEATHER WILL SPREAD INTO THE DISTRICT.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FIRE WEATHER WATCH TUESDAY AFTERNOON AND EVENING FOR FIRE ZONES
AZZ131 AND AZZ132.

CA...FIRE WEATHER WATCH TUESDAY AFTERNOON AND EVENING FOR FIRE ZONE
CAZ231.

&&

$$

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

DISCUSSION...CB
PREVIOUS DISCUSSION...MEYERS/MO
AVIATION...MO
FIRE WEATHER...MO/CK












000
FXUS65 KPSR 211531
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
830 AM MST MON APR 21 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE AREA EARLY THIS WEEK LEADING TO
SUNNY DAYS...CLEAR NIGHTS...AND SHARPLY WARMER AFTERNOON HIGH
TEMPERATURES. BREEZY TO WINDY CONDITIONS WILL DEVELOP OVER MUCH OF
THE AREA TUESDAY AFTERNOON INTO WEDNESDAY AS A DRY WEATHER SYSTEM
PASSES TO THE NORTH. TEMPERATURES WILL FALL ONLY SLIGHT IN RESPONSE
TO THIS WEATHER SYSTEM...CLOSER TO SEASONAL NORMALS FOR THE
REMAINDER OF THE WEEK.

&&

.DISCUSSION...
UPPER LEVEL HIGH PRESSURE RIDGE HAS BUILT INTO THE DESERT SOUTHWEST
WITH H5 HEIGHTS NEARLY 582DM ACROSS THE SRN AZ DESERT. IR IMAGERY
SHOWED SUNNY SKIES ACROSS THE REGION AT 8 AM. AREA SOUNDINGS ALL
INDICATE ABOUT 5F WARMING BELOW 700MB...SO EXPECT HIGH TEMPS TODAY
TO CLIMB ANOTHER SEVERAL DEGREES ONCE THE GOOD MIXING BEGINS IN THE
LATE MORNING TO EARLY AFTN. LOOK FOR THE WARMER DESERTS TO CLIMB
INTO THE MID 90S TO NEAR 100 DEGREES TODAY. CURRENT FORECASTS ARE IN
GOOD SHAPE AND NO UPDATES ARE NEEDED ATTM.

.PREVIOUS DISCUSSION...
WATER VAPOR IMAGERY CLEARLY SHOWS AN EXPANDING ANTICYCLONE OVER
ARIZONA AND PORTIONS OF THE INTERMOUNTAIN WEST...WITH A BROAD
DEEPENING 532DM UPPER LEVEL LOW SPINNING OVER THE GULF OF ALASKA
INTO BRITISH COLUMBIA. REGIONAL UPPER AIR PLOTS OVER THE DESERT
SOUTHWEST HAVE SHOWN AROUND A 70M INCREASE IN 500MB HEIGHTS OVER THE
LAST 24 HOURS OR SO...AND THIS WILL LEAD TO ADDITIONAL WARMING FOR
OUR FORECAST AREA TODAY WITH AFTERNOON TEMPERATURES ACROSS THE LOWER
DESERTS RISING INTO THE MID TO UPPER 90S. WITH THE DRIER NATURE OF
THE ATMOSPHERE AND PLENTY OF SUNSHINE...IT WILL NOT BE OUT OF THE
QUESTION FOR SOME LOCATIONS TO FLIRT WITH THE CENTURY MARK FOR THE
FIRST TIME THIS YEAR.

OPERATIONAL MODELS AND NUMERICAL GUIDANCE ARE STILL IN VERY GOOD
AGREEMENT WITH TRACK OF THE UPPER LEVEL LOW OVER THE GULF OF
ALASKA...DROPPING IT SOUTH ALONG THE WEST COAST AND MOVING AN OPEN
WAVE INLAND INTO THE GREAT BASIN BY TUESDAY MORNING. THE SYSTEM WILL
IMPORT LITTLE IN THE WAY OF MOISTURE...BUT MID AND LOWER LEVEL
PRESSURE GRADIENTS WILL TIGHTEN UP AS THE TROUGH PASSES TO OUR
NORTH...GENERATING BREEZY TO WINDY CONDITIONS ACROSS SOUTHEAST
CALIFORNIA AND SOUTHWEST ARIZONA -- WITH SUSTAINED WINDS 15-25 MPH
AND GUSTS TO 35 MPH COMMON ACROSS OUR WESTERN ZONES TUESDAY
AFTERNOON AND EVENING. SOME LOCATIONS IN AND AROUND THE IMPERIAL
VALLEY/EL CENTRO CA...JOSHUA TREE NATIONAL PARK...AND OTHER HIGHER
TERRAIN AREAS IN LA PAZ COUNTY AZ MAY EXPERIENCE STRONGER WINDS AND
SOME AREAS OF BLOWING DUST/SAND. RIGHT NOW...FORECAST WIND SPEEDS
ARE NOT MEETING WIND ADVISORY CRITERIA...BUT IT WILL BE SOMETHING
FOR FUTURE SHIFTS TO FOLLOW/MONITOR.

THE LOW LEVEL FRONTAL PASSAGE SHOULD CLEAR THE FORECAST AREA BY
WEDNESDAY MORNING...WITH MODEST HEIGHT FALLS AND COOLER AIR HELPING
DROP DAYTIME TEMPS CLOSE TO CLIMATOLOGICAL NORMAL WEDNESDAY
AFTERNOON...MAINLY BACK INTO THE MID TO UPPER 80S OVER THE LOWER
DESERTS. LESS WIND IS EXPECTED WEDNESDAY HOWEVER IT WILL STILL BE ON
THE BREEZY SIDE DURING THE AFTERNOON HOURS.

SHORTWAVE RIDGING COMMENCES THURSDAY...WITH 500MB HEIGHTS REBOUNDING
TO NEAR 576DM OVER SOUTHERN CA AND AZ BY FRIDAY. ENSEMBLE SPREAD
CONTINUES TO GROW FOR THE WEEKEND TIME FRAME WITH EACH FORECAST
ITERATION. THE MODEL TREND OF NEGATIVE HEIGHT ANOMALIES COVERING THE
NORTHEAST PACIFIC BASIN REMAINS CONSISTENT...HOWEVER THE SUBSEQUENT
PROGRESSION OF SHORTWAVES INTO THE WESTERN AND CENTRAL CONUS IS
HIGHLY UNCERTAIN.

OPERATIONAL MEMBERS HAVE RETAINED GOOD RUN TO RUN CONTINUITY...WITH
THE GFS CURRENTLY DEEPENING A 541DM CLOSED LOW INTO THE SOUTHWESTERN
CONUS OVER THE WEEKEND...WHILE THE ECMWF EJECTS SEVERAL WEAKER LEAD
WAVES THROUGH THE DOWNSTREAM QUASI-ZONAL FLOW WHILE MAINTAINING
GENERAL EAST PACIFIC TROUGHING. THE OPERATIONAL GEM IS SOMEWHAT OF A
COMPROMISE OF THESE TWO EXTREMES...BUT IT CONTINUES TO FAVOR SOME
MEASURE OF DEEPER TROUGHING NEAR THE FORECAST AREA.

ENSEMBLE MEMBERS STILL EXHIBIT A VAST ARRAY OF POSSIBLE OUTCOMES...
RESULTING IN A LOWER FORECAST CONFIDENCE FOR THE WEEKEND. AT THIS
TIME...UNLESS THE SYSTEM DIGS EVEN DEEPER WEST OF CALIFORNIA...ANY
SOLUTION WILL BE CONSIDERABLY DRY WITH PRECIPITATION CHANCES
SLIGHT/SLIM FOR OUR FORECAST AREA. THERE IS SOME AGREEMENT AS TO
LOWER HEIGHTS SPLAYED OVER THE REGION...WITH A TIGHTENED GRADIENT
SOMEWHERE IN THE 564DM RANGE STRETCHED ACROSS SOUTHEAST CA AND
SOUTH-CENTRAL AZ. AS SUCH...ELECTED TO DROP FORECAST DAYTIME
TEMPERATURES BACK INTO THE LOW 80S FOR THE WEEKEND...ALONG WITH
BREEZY TO WINDY CONDITIONS AGAIN SATURDAY AND SUNDAY.

&&

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

NO SIGNIFICANT AVIATION CONCERNS THROUGH TUESDAY MORNING AS MOSTLY
CLEAR SKIES AND LIGHT WINDS WILL PREVAIL ACROSS THE REGION. THE
DAILY WESTERLY WIND SHIFT OVER CENTRAL ARIZONA SHOULD TEMPORALLY
OCCUR SIMILARLY TO YESTERDAY (EARLY AFTERNOON)...HOWEVER CONFIDENCE
IS FAIRLY HIGH THAT THE WESTERLY COMPONENT WILL PREVAIL THROUGHOUT
MUCH OF THE OVERNIGHT. ACROSS SE CALIFORNIA...A PREVAILING S/SW WIND
SHOULD DEVELOP THOUGH PRECISE ONSET TIMING IS SLIGHTLY MORE
UNCERTAIN.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
HIGH PRESSURE WILL START BUILDING INTO THE REGION ON
WEDNESDAY...HOWEVER LOCALLY BREEZY CONDITIONS WILL STILL
PERSIST...PARTICULARLY DURING THE EARLY AFTERNOON BEFORE THE
PRESSURE GRADIENT RELAXES BY THE EVENING. ANOTHER STRONG PACIFIC LOW
PRESSURE SYSTEM WILL PROPAGATE INTO THE REGION FRIDAY THROUGH
SUNDAY...ALLOWING WINDS TO STRENGTHEN...AND CREATING ANOTHER PERIOD
OF ELEVATED FIRE DANGER. MINIMUM HUMIDITIES WILL FALL INTO THE
SINGLE DIGITS ACROSS THE LOWER DESERTS THROUGH FRIDAY...BEFORE
SEEING A SLIGHT IMPROVEMENT MAINLY IN THE TEENS OVER THE WEEKEND AS
SOMEWHAT COOLER WEATHER WILL SPREAD INTO THE DISTRICT.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FIRE WEATHER WATCH TUESDAY AFTERNOON AND EVENING FOR FIRE ZONES
AZZ131 AND AZZ132.

CA...FIRE WEATHER WATCH TUESDAY AFTERNOON AND EVENING FOR FIRE ZONE
CAZ231.

&&

$$

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

DISCUSSION...CB
PREVIOUS DISCUSSION...MEYERS/MO
AVIATION...MO
FIRE WEATHER...MO/CK













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