Area Forecast Discussion
Issued by NWS Phoenix, AZ

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FXUS65 KPSR 301713
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1012 AM MST TUE JUN 30 2015

.SYNOPSIS...
OCCASIONAL SHOWERS AND THUNDERSTORMS WILL BE COMMON ACROSS THE
MOUNTAINS OF SOUTHERN AND EASTERN ARIZONA THROUGH MUCH OF THE WEEK.
THERE WILL BE SOME OPPORTUNITY FOR SHOWERS TO AFFECT LOWER ELEVATION
DESERT COMMUNITIES DURING THE MIDDLE OF THE WEEK...HOWEVER THE MOST
LIKELY OUTCOME IN THESE AREAS WILL ONLY BE GUSTY WINDS AND SOME
BLOWING DUST. AFTERNOON TEMPERATURES WILL REMAIN SLIGHTLY ABOVE
NORMAL THIS WEEK BEFORE MODERATING BACK DOWN TOWARDS NORMAL BY THE
WEEKEND.

&&

.DISCUSSION...
WESTERN CONUS WV IMAGERY THIS MORNING SHOWS THE BROAD RIDGE
CIRCULATION OVER THE GREAT BASIN AND CARVING INTO PORTIONS OF THE
GREAT PLAINS...WITH ML/HL MOISTURE STREAMING UP INTO SOUTHERN
CA/GREAT BASIN AND SOMEWHAT DRIER AIR OVER PORTIONS OF TX/NM. BACK
CLOSER TO HOME...CONVECTION CONTINUES OVER PORTIONS OF WESTERN PIMA
COUNTY AND NORTHERN SONORA THIS AM...ALONG A WEAK INVERTED WAVE
FEATURE AND AREA OF ENHANCED STEERING FLOW TRACKING ALONG THE INTL
BORDER. FLOW. THE STRONGEST STORMS OVER THE LAST FEW HOURS HAVE
GENERALLY REMAINED SOUTH OF THE BORDER...BUT HAVE SPREAD A HEALTHY
LL MOISTURE INCREASE INTO THE YUMA AND IMPERIAL VALLEY AREAS WITH
DEWPOINTS PUSHING 70F THIS MORNING. FIRST UPDATE FOR THE GRIDS THIS
AM WAS TO INCLUDE ISOLATED THUNDERSTORM MENTION ACROSS SOUTHWEST AZ
PUSHING INTO BEYOND THE CO RIVER VALLEY AND INTO SOUTHEAST CA FOR
THE NEXT FEW HOURS. GIVEN THE EXCESS LL/ML MOISTURE...HEAVY RAINFALL
ALONG WITH STRONG GUSTY WINDS ARE EXPECTED STORM THREATS WITH THE
STRONGER...MORE ORGANIZED STORMS.

12Z RAOBS PAINT AN INTERESTING LATE JUNE PICTURE ACROSS THE
SOUTHWEST...AS 850MB DEWPOINTS ARE PUSHING 10C...KTWC HAS A 9C 700MB
DEWPOINT...AND WINDS THROUGH THE 700-500MB STEERING LEVELS VARY FROM
20 TO 40KTS ACROSS SOUTHERN AND SOUTH-CENTRAL AZ. MORNING SOUNDINGS
AROUND THE AREA TOUT ML CAPES IN THE 1000-1500 J/KG RANGE AND
MUCAPES PUSHING 1500 J/KG...WHICH EVENTUALLY MAY MIX DOWN AROUND
1000 J/KG BY THE AFTERNOON THROUGHOUT THE AREA. IN ADDITION...WV
LOOPS FROM ACROSS WEST TX THIS MORNING INDICATE SOME SORT OF ML VORT
MAX/MCV QUICKLY HEADING WEST-SOUTHWESTWARD INTO CHIHUAHUA THIS AM.
CURRENT TRAJECTORY OF THIS FEATURE HAS IT SINKING FURTHER INTO OLD
MEXICO TODAY...BUT WITH DECENT EASTERLY STEERING FLOW...IT COULD
CLIP PART OF THE REGION LATER TODAY AND CERTAINLY STAND TO HELP
INITIATE AND PROLONG ANY OTHER CONVECTION THAT DOES DEVELOP ACROSS
THE EASTERN THIRD/HIGHER TERRAIN PORTION OF THE STATE.

UPDATES TO THE SHORT TERM GRIDS INCLUDED FINE TUNING THE TIMING OF
POPS ACROSS THE AREA AND ELEVATING CHANCES OVER THE OVERNIGHT HOURS
TO INCLUDE CHANCE MENTIONING FOR THE LOWER DESERTS...INCLUDING
PHOENIX...FOR THE EVENING HOURS. CURRENT THOUGHTS ARE CONDITIONS MAY
BE SIMILAR TO THOSE FROM LAST EVENING...WITH SEVERAL OUTFLOW
INTRUSIONS FROM PERIPHERAL STORMS TO MOVE INTO THE LOWER DESERTS TO
HELP INITIATE ACTIVITY LATER INTO THE EVENING.

&&

.PREVIOUS DISCUSSION /ISSUED AT 328 AM MST/PDT/...
OPERATIONAL MODELS CONTINUE TO PLACE THE CENTER OF THE 594-596DM
ANTICYCLONE OVER UTAH TODAY...THE CENTER ELONGATING AND THE AXIS
TAKING ON A NW TO SE ORIENTATION OVER NEVADA AND INTO NEW MEXICO BY
WEDNESDAY AFTERNOON. AS THE HIGH REPOSITIONS...A WAVE OR TWO ROTATES
AROUND THE SOUTHERN PERIPHERY OF THE HIGH. THESE FEATURES WILL HELP
TO ENHANCE PRECIPITATION CHANCES TODAY AND WEDNESDAY...ALBEIT STILL
SLIGHT CHANCES FOR THE LOWER DESERTS...AND THE BEST CHANCES OVER THE
HIGHER TERRAIN EAST OF PHOENIX. DAYTIME TEMPERATURES THROUGH THE
MAJORITY OF THE WORK WEEK WILL REMAIN ON THE ABOVE-NORMAL SIDE...
RANGING 105-110F OR SO WITH FAIRLY MILD OVERNIGHTS.

THE UPPER LEVEL HIGH REMAINS IN A NW-SE ORIENTED FASHION THROUGH
FRIDAY. THIS CONFIGURATION WILL CONTINUE TO PROMOTE A LOW GRADE
MONSOON PATTERN AND DAILY CONVECTION DEPENDENT ON HOW INSTABILITY
MODIFIES OVER TIME. PRECIPITATION CHANCES DWINDLE A BIT THURSDAY
AND FRIDAY AS THE LOW LEVEL FLOW IS REALLY NOT CONDUCIVE TO
IMPORTING RICHER MOISTURE INTO THE REGION. SO...THE BEST PRECIP
CHANCES WILL BE LIMITED TO HIGHER TERRAIN LOCATIONS DURING THIS TIME
FRAME AS MOISTURE MAY BEGIN TO MIX OUT AT LOWER ELEVATIONS.

HOWEVER...BY SATURDAY-SUNDAY...THE HIGH BEGINS TO SHIFT AND THE AXIS
ONCE AGAIN ALIGNING NORTH TO SOUTH OVER THE INTERMOUNTAIN WEST...
THE HIGH 500-300MB CENTERS STACKING/CO-LOCATING NEAR THE FOUR
CORNERS AREA. THIS IS A VERY FAVORABLE POSITION OF THE HIGH FOR
SOUTHEAST FLOW AND GOOD MOISTURE ADVECTION.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...KSDL...
THUNDERSTORM CHANCES LATER THIS EVENING AND TONIGHT WILL BE THE
PRIMARY AVIATION CONCERN FOR CNTRL AZ TERMINALS. IN THE NEAR
TERM...ONLY SCT MID/HIGH CLOUDS AND ELY WINDS SWITCHING TO WLY BY
MID/LATE MORNING WILL LEAD TO LITTLE TO NO IMPACTS. ENOUGH MODEL
EVIDENCE EXITS TO INCLUDE A VCTS MENTION LATE THIS EVENING. MUCH
LIKE LAST NIGHT...COVERAGE MAY BE QUITE LIMITED TO NOT DIRECTLY
AFFECT A SPECIFIC TERMINAL LOCATION...BUT POSSIBLY APPROACHES AND
DEPARTURE ROUTES.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
THERE IS A SLIGHT CHANCE FOR AVIATION IMPACTS IN THE FORM OF SHRA
AND TSRA LATE IN THE PERIOD (WED MORNING) WITH ACTIVITY MOVING EAST
FROM ARIZONA. COVERAGE MAY BE LIMITED AND AND STORMS DECAYING SUCH
THAT ONLY A VCSH INTRODUCTION WAS JUSTIFIED. OTHERWISE...ONLY
MID/HIGH CLOUDS AND LIGHT S/SE SFC WINDS THROUGH THE AFTERNOON WILL
OFFER GOOD FLYING CONDITIONS IN THE SHORT TERM.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
A LOW GRADE MONSOON PATTERN WILL BE IN PLACE THROUGH THE WEEK...
CHARACTERIZED BY NEAR OR SLIGHTLY ABOVE NORMAL TEMPERATURES...AND
WIDELY SCATTERED AFTERNOON AND EVENING SHOWERS/THUNDERSTORMS THAT
MOVE FROM EAST TO WEST OFF THE MOUNTAINS AND INTO THE LOWER DESERTS
EACH DAY. FOR THURSDAY INTO SATURDAY THE STORMS WILL PRIMARILY FOCUS
OVER THE HIGHER TERRAIN WITH RATHER LOW CHANCES OF SURVIVING INTO
THE LOWER DESERTS. SUNDAY INTO EARLY NEXT WEEK...AS HUMIDITIES RISE
THERE WILL BE A BETTER CHANCE OF THUNDERSTORMS AND SHOWERS MOVING
INTO THE CENTRAL DESERTS DURING THE OVERNIGHT HOURS. DAYTIME
HUMIDITY VALUES GENERALLY WILL BE IN THE UPPER TEENS TO MID 20
PERCENT RANGE THROUGH SATURDAY WITH HUMIDITIES RISING SEVERAL
PERCENT BY MONDAY. VERY GOOD OVERNIGHT RECOVERY IS EXPECTED EACH
NIGHT. WINDS EACH DAY WILL BE LIGHT AND FAVOR SOUTHWESTERLY
DIRECTIONS THROUGH FRIDAY...BECOMING SOUTHERLY BY THE WEEKEND.

&&

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


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