Area Forecast Discussion
Issued by NWS Phoenix, AZ

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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 051015
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
315 AM MST WED AUG 5 2015

.SYNOPSIS...
MOSTLY CLEAR SKIES AND DRY WEATHER WILL PREVAIL ACROSS THE REGION
TODAY...WITH HIGH TEMPERATURES ON THE LOWER DESERTS RANGING FROM 112
TO 115 DEGREES. MONSOON HUMIDITY WILL RETURN TO THE AREA THURSDAY
AND FRIDAY...PROVIDING A THREAT OF AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS ALONG WITH COOLER AFTERNOON TEMPERATURES REGION-WIDE.
A MORE STABLE AND DRIER PATTERN WILL SHIFT MOST OF THE MONSOON
MOISTURE AND THREAT FOR SHOWERS INTO EASTERN ARIZONA THIS WEEKEND.

&&

.DISCUSSION...
SATELLITE IMAGERY SHOWS VERY LITTLE IN THE WAY OF CLOUD COVER OVER
OUR FORECAST AREA THIS MORNING. THE UPPER LEVEL ANTICYCLONE WITH 594-
596DM 500MB HEIGHTS CONTINUES TO CENTER OVER OVER ARIZONA/NEW
MEXICO...AND ALONG WITH THE DRIER SOUTHWESTERLY FLOW...THERE IS
LITTLE IN THE WAY OF ANY STORM ACTIVITY THAT IS EXPECTED TODAY. AT
THE SURFACE...WITH THE LACK OF CLOUDS...MANY SITES ACROSS OUR CWA
HAVE DROPPED NICELY INTO THE UPPER 80S. HOWEVER...AT PHOENIX SKY
HARBOR...TEMPS HAVE BEEN SLOW TO FALL OVERNIGHT...AND THE
THERMOMETER APPEARS TO BE STUCK AT A VERY WARM 96 DEGREES...KIND OF
A SLIM OPPORTUNITY TO REACH THE COOLER FORECAST TEMP OF 88 DEGREES.

WITH THE WARM START TO THE MORNING...THE EXCESSIVE HEAT WARNING WILL
CONTINUE FOR OUR LOWER DESERTS...WITH AFTERNOON TEMPS TOPPING OUT IN
THE 109-114 DEGREE RANGE. HOWEVER...THE HOT DRY SUBSIDENT PATTERN
CHANGES LATTER THIS EVENING AS THE MID AND UPPER LEVEL FLOW BECOMES
MORE SOUTHERLY AND BEGINS TO IMPORT INCREASING CLOUDS INTO SOUTHERN
ARIZONA. ANY INCREASE IN LOW LEVEL MOISTURE INTO THE SOUTHWEST
DESERTS IS EXPECTED TO ARRIVE OVERNIGHT INTO THURSDAY MORNING.

THURSDAY AND FRIDAY...SOUTHERLY LOW LEVEL WINDS WILL START TO ADVECT
INCREASING AMOUNTS OF LOW LEVEL MONSOON MOISTURE INTO SOUTHERN
ARIZONA...EVENTUALLY OVERSPREADING THE AREA FRIDAY. THERE IS A
THREAT OF AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS THURSDAY AS
THE LOWER LEVELS OF THE ATMOSPHERE QUICKLY DESTABILIZE ACROSS
PORTIONS OF SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA...AT THE SAME
THIS AREA IS UNDER FAVORABLE UPPER LEVEL DEFORMATION/DIFFLUENCE.
THE THREAT OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL
SHIFT OVER PORTIONS OF THE SOUTH-CENTRAL ARIZONA FRIDAY.

SATURDAY AND SUNDAY...A DRIER AND MORE STABLE AIRMASS WILL SPREAD
INTO OUR FORECAST AREA FROM THE WEST THIS WEEKEND...KEEPING STORMS
CONFINED TO EASTERN ARIZONA. EXCEPT FOR A SLIGHT CHANCE OF AFTERNOON
SHOWERS AND THUNDERSTORMS OVER THE HIGHER TERRAIN AND MOUNTAINS OF
SOUTHERN GILA COUNTY/ZONE 24...THE REMAINDER OF OUR FORECAST AREA
WILL BE DRY.

MONDAY AND TUESDAY...MODELS CONTINUE TO SUGGEST A SIGNIFICANT UPPER
LEVEL INVERTED TROUGH TO MOVE INTO FAR SOUTHEAST ARIZONA MONDAY
AFTERNOON AND CONTINUE NORTH TOWARD PHOENIX MONDAY NIGHT. THIS COULD
BE A SIGNIFICANT SHOWER/THUNDERSTORM EVENT...HOWEVER SINCE THIS
SYSTEM IS STILL TOO FAR AWAY...THE BEST APPROACH IS TO INTRODUCE A
THREAT OF SHOWERS AND THUNDERSTORMS OVER SOUTH CENTRAL AZ
MONDAY...MONDAY NIGHT AND TUESDAY.

&&

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

MOSTLY CLEAR SKIES AND LIGHT DIURNALLY DRIVEN WINDS WILL PREVAIL AT
ALL TAF SITES THROUGH AT LEAST LATE WEDNESDAY NIGHT.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
AN INCREASE IN MOISTURE WILL BRING CHANCES OF AFTERNOON AND EARLY
EVENING SHOWERS AND THUNDERSTORMS TO SOUTH CENTRAL ARIZONA ON FRIDAY
WHILE ACTIVITY WILL BE MOSTLY LIMITED TO HIGHER TERRAIN AREAS EAST OF
PHOENIX FOR THE WEEKEND. AN ADDITIONAL MOISTURE SURGE WILL THEN
INCREASE CHANCES OF SHOWERS AND THUNDERSTORMS ACROSS SOUTHERN ARIZONA
FOR EARLY NEXT WEEK. MINIMUM RELATIVE HUMIDITIES OF 15 TO 20 PERCENT
RANGE WILL BE COMMON FOR MUCH OF THE PERIOD ACROSS THE DESERTS. HIGH
TEMPERATURES WILL BE AROUND OR SLIGHTLY ABOVE NORMAL. WINDS WILL BE
LIGHT THROUGH MUCH OF THE PERIOD FOLLOWING TYPICAL DIURNAL DIRECTIONS
EXCEPT FOR AFTERNOON UPSLOPE BREEZES GUSTING AT TIMES UP TO 20 MPH.

&&

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

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...EXCESSIVE HEAT WARNING FROM 11 AM TO 8 PM MST WEDNESDAY FOR
     AZZ020>023-025>028.

CA...EXCESSIVE HEAT WARNING FROM 11 AM TO 8 PM PDT WEDNESDAY FOR
     CAZ031>033.

&&

$$

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

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


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