Area Forecast Discussion
Issued by NWS Phoenix, AZ

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS65 KPSR 030943 AAA
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
245 AM MST FRI JUL 3 2015

.UPDATE...UPDATED AVIATION DISCUSSION.

.SYNOPSIS...RELATIVELY HIGH MONSOON HUMIDITY AND A SLIGHTLY STABLE
ATMOSPHERE WILL KEEP THE CHANCE OF SHOWERS AND THUNDERSTORMS OVER
SOUTH CENTRAL ARIZONA TODAY...GENERALLY FROM PHOENIX EASTWARD. THE
THREAT FOR SHOWERS THIS WEEKEND WILL EXPAND INTO PARTS SOUTHWEST
ARIZONA DURING THE AFTERNOON AND EVENINGS. BY NEXT WEEK...DRIER
WESTERLY FLOW WILL PUSH MOST OF THE MONSOON MOISTURE INTO EASTERN
ARIZONA WHERE THE THREAT OF THUNDERSTORMS WILL CONTINUE.

&&

.DISCUSSION...

THIS MORNING...ISOLATED SHOWERS THAT DEVELOPED OVER SOUTHERN GILA
COUNTY JUST BEFORE MIDNIGHT HAVE EXPANDED WEST AND WILL LIKELY
CONTINUE OVER PARTS THE GREATER PHOENIX AREA...SOUTH TO COOLIDGE AND
CASA GRANDE INTO THE MORNING HOURS. THESE SHOWERS WERE UNEXPECTED
AND THE MECHANISM FOR THEIR DEVELOPMENT WAS HARD TO DISCERN...
ALTHOUGH ITS RELATED TO AN UNUSUALLY STRONG 40-50 KNOT 300-250 MB
SOUTHEASTERLY JETSTREAM EXTENDING ACROSS THE WESTERN HALF OF AZ. THE
LATEST HRRR MODEL HAD A GOOD HANDLE ON THE 07Z SHWR DEVELOPMENT...
AND FORECASTS IT TO EXTEND WEST INTO THE GREATER PHOENIX AND CASA
GRANDE AREAS...OR THE LOWER DESERTS THROUGH 16Z FRI.

THE REMAINDER OF FRIDAY AFTERNOON AND EVENING SHOULD BE DRY...WITH
THE EXCEPTION OF MOUNTAINOUS SOUTHERN GILA COUNTY ZONE 24. I.E...A
FEW SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS AFTERNOON AND
EVENING IN ZONE 24.


SATURDAY AND SUNDAY...

MODELS FORECAST THE 300/250 MB HIGH CENTERS TO MOVE SOUTHWARD FROM
FAR NORTHEAST AZ FRIDAY MORNING...TO THE VICINITY OF EL PASO THIS
WEEKEND. THIS PATTERN VEERS THE BELT OF UNUSUALLY STRONG 300/250 MB
40-50 KNOT SOUTHEASTERLY WINDS...TO SOUTHERLY WINDS CENTERED ALONG
THE COLORADO RIVER VALLEY. A FEW HARD TO TIME DISTURBANCES...AS WELL
AS PERIODS OF DIVERGENT FLOW ALOFT DEVELOPS ACROSS SOUTHWEST AND
SOUTH CENTRAL AZ. THIS PORTENDS A THREAT OF AFTN/EVE SHWRS AND TSTMS
SAT AND SUN.


MONDAY THROUGH FRIDAY...

LATEST GFS MODEL FORECASTS HAVE CHANGED SINCE YDA...AND NOW
FORECASTS THE MID/UPPER LEVEL FLOW TO BECOME MORE WESTERLY THRU
FRIDAY. ONLY ONE PERTURBATION IS FORECAST TO MOVE INTO AZ ABOUT
TUESDAY. AS A RESULT...MOST OF THE BOUNDARY LAYER MOISTURE GETS
PUSHED INTO THE EASTERN HALF OF THE STATE. THEREFORE THE CONVECTIVE
POTENTIAL WILL FAVOR THE MOUNTAINS NORTH THROUGH EAST OF PHOENIX.
MID LEVEL STEERING CURRENTS ALSO BECOME WESTERLY. THEREFORE A ONLY A
SLIGHT CHANCE OF LATE AFTERNOON/EVENING STORMS ARE FORECAST ON THE
SOUTH CENTRAL DESERTS...WITH SLIGHTLY HIGHER PROBABILITIES IN OUR
MOUNTAINOUS ZONE 24 EAST OF PHOENIX.


SATURDAY...

MODELS FORECAST AN INVERTED TROF IN THE EASTERLIES TO ROTATE OUT OF
WEST TEXAS THURSDAY NIGHT...AND INTO SOUTHERN AZ FRIDAY NIGHT OR
SATURDAY MORNING. NOT MUCH CREDIENCE IS PUT INTO THE EXTENDED MODEL
FORECASTS DURING THE MONSOON...THEREFORE WE WILL CONTINUE WITH THE
LOW GRADE MONSOON THREAT OF AFTN/EVE SHWRS AND TSTMS OVER
PINAL...EASTERN MARICOPA...AND SOUTHERN GILA COUNTIES.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...KSDL... AFTER SOME
THUNDERSTORM ACTIVITY EARLY THIS MORNING...WHICH COULD ONCE AGAIN
AFFECT ONE...OR MORE OF THE TERMINALS...A RATHER QUIET REMAINDER OF
THE TAF PERIOD IS EXPECTED AS THUNDERSTORM ACTIVITY IS PUSHED BACK
WELL TO THE EAST AND NORTH OF THE TAF SITES. DEBRIS CLOUDINESS FROM
THE CURRENT ROUND OF THUNDERSTORM ACTIVITY WILL LINGER THROUGH THE
REMAINDER OF THE MORNING...WITH MAINLY SCT MID-HIGH CLOUD LAYERS
FORECAST FOR THIS AFTERNOON AND EVENING. OTHERWISE...CONDITIONS LOOK
GENERALLY UNFAVORABLE FOR CONVECTION IN THE LOWER DESERTS FRIDAY
AFTERNOON/EVENING. WINDS TO MAINLY FOLLOW TYPICAL DIURNAL TRENDS
THROUGH THE TAF PERIOD...WITH THE WESTERLY BREEZES THIS AFTERNOON
NOT BEING QUIET OD STRONG AS WE HAVE SEEN THE LAST COUPLE OF DAYS.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND
KBLH... JUST A FEW HIGH CLOUDS AT BOTH SE CA SITES THROUGH THE TAF
PERIOD...WITH WINDS MAINLY FOLLOWING TYPICAL DIURNAL TRENDS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
TYPICAL MONSOON WEATHER EXPECTED ON SUNDAY...FOLLOWED BY DRYING AND
A RE-ORIENTING OF HIGHEST STORMS CHANCES WELL NORTH/EAST OF PHOENIX
MONDAY THROUGH MID WEEK. THIS WILL RESULT IN AFTERNOON HUMIDITIES IN
THE 10-20 PERCENT RANGE WITH FAIR/GOOD OVERNIGHT RECOVERIES
EXPECTED. WINDS WILL FAVOR TYPICAL DIURNAL UPSLOPE/DOWNVALLEY TRENDS
NEXT WEEK OUTSIDE OF THUNDERSTORM INDUCED OUTFLOWS.

&&

.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT ANY SIGNIFICANT WEATHER CONDITIONS
ACCORDING TO STANDARD OPERATING PROCEDURES.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&

$$

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

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



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.