001 
FXUS65 KPSR 152132
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
230 PM MST SUN JUL 15 2012

.SYNOPSIS... 
MONSOONAL MOISTURE WILL REMAIN ACROSS THE DESERT 
SOUTHWEST...HOWEVER STEADILY DECREASE THROUGH MIDWEEK. 
CORRESPONDINGLY...RAINFALL CHANCES WILL ALSO DECREASE THOUGH 
TEMPERATURES SHOULD STAY BELOW AVERAGE. THE BELOW-AVERAGE RAIN 
CHANCES WILL LARGELY PERSIST THROUGH THE END OF THE WEEK WITH A 
GENERAL WARMING TREND...THOUGH MOISTURE MAY TRY TO START WORKING 
WESTWARD INTO THE AREA BY THE WEEKEND.

&&

.DISCUSSION...
THE VORT CENTER THAT ENHANCED LIFT OVER THE REGION YESTERDAY HAS 
LIFTED INTO SWRN UTAH THIS MORNING...THOUGH THE BROAD TROUGH AXIS 
AND SOUTHWESTERLY SIDE OF THE CYCLONIC FLOW ALOFT REMAINS ANCHORED 
OVER THE DESERT SOUTHWEST. A SECONDARY SHORTWAVE WAS DIVING 
SOUTHEASTWARD THROUGH CENTRAL CALIFORNIA...PRODUCING FAVORABLY 
STRONG DIFLUENT FLOW OVER SRN NEVADA. AN ANTI-CYCLONIC CIRCULATION 
ALONG THE INTERNATIONAL BORDER WAS PROVIDING MORE CONVERGENT FLOW 
THROUGH CNTRL/SRN ARIZONA UNSUPPORTIVE FOR PERSISTENT DEEP 
UVV...WITH THE BETTER DIFLUENCE RELEGATED TO NRN MEXICO IN THE 
NORTHEASTERLY FLOW ON THE SOUTHEAST PERIPHERY OF THE HIGH PRESSURE 
CENTER ALOFT.

12Z SOUNDING DATA SHOWED A DEEP MOIST ATMOSPHERIC COLUMN...THOUGH 
ONLY 1.65 INCHES AS COMPARED TO 2.00 INCHES YESTERDAY (STILL ABOVE 
NORMAL). MOISTURE IN THE MIXING LAYER SUGGESTS 11-12 G/KG WILL BE 
MAINTAINED TODAY (LOWER/MID 60 DEWPOINTS AT LOW 
ELEVATIONS)...YIELDING MLCAPES AOA 2000 J/KG ONCE AGAIN (OBJECTIVE 
ANALYSIS SUGGESTS THESE INSTABILITY LEVELS HAVE BEEN REACHED 
ALREADY). OTHER THAN MOISTURE PROFILES...THE BIGGEST DIFFERENCE IN 
THIS MORNINGS SOUNDINGS ARE STEEPER MIDLEVEL LAPSE RATES WITHIN THE 
COLD CORE ALOFT...AND MUCH BETTER DEEP LAYER SHEAR PROFILES 
(POTENTIALLY AIDING IN A MORE ORGANIZED SVR THREAT IN THE FORM OF 
GUSTY OUTFLOW WINDS AND LARGE HAIL VERSUS THE PAST COUPLE DAYS). 

IT IS STILL DIFFICULT TO IDENTIFY A LOCAL DYNAMIC FORCING MECHANISM 
THIS AFTERNOON ON SATELLITE IMAGERY. VISIBLE IMAGERY DOES NOT SHOW 
ANY OUTFLOW BOUNDARIES...AND 20Z REGIONAL ANALYSIS INDICATES 
DIVERGENCE RELEGATED TO THE AZ/NM BORDER...WITH FORECASTS ONLY 
FOCUSING LIFT NEAR THE RIGHT REAR JET ENTRANCE REGION THROUGH THIS 
AFTERNOON. THUS FAR...CONVECTIVE UPDRAFTS HAVE STRUGGLED TO MAINTAIN 
UPRIGHT INTEGRITY...THOUGH WITH CONVECTIVE TEMPERATURES BEING 
REACHED IN THE MID 90S...MORE ROBUST DEVELOPMENT HAS BEEN OBSERVED. 
THE BEST TRAJECTORIES FOR BRINGING ACTIVITY INTO THE PHOENIX AREA 
WOULD BE ALONG THE WESTERN EDGE OF THE MOISTURE PLUME...AND DEEP 
CONVECTIVE ORGANIZATION WEST OF TUCSON THROUGH CENTRAL AND WESTERN 
PIMA COUNTY.

SOUTHWESTERLY FLOW WILL BE MAINTAINED AND STRENGTHEN MONDAY AS AN 
UNSEASONABLY STRONG NEGATIVE HEIGHT ANOMALY DIVES SOUTH TOWARDS THE 
NORTHERN CALIFORNIA COAST. AN ANTI-CYCLONIC CIRCULATION WILL ALSO 
REMAIN OVER NORTHERN MEXICO...CREATING A SIMILAR DYNAMIC FLOW 
PATTERN TO TODAY. GREATEST UNCERTAINTY LIES WITH MOISTURE 
AVAILABILITY...WHERE TYPICALLY THE STRONGER SWLY FLOW WOULD SCOUR 
OUT MOISTURE...HOWEVER THIS PROCESS MAY TAKE LONGER THAN USUAL. HAVE 
TRENDED HIGHEST POPS TOWARDS THE EASTERN GRIDS WHERE DEEP MOISTURE 
WILL BE MOST PLENTIFUL AND TRAJECTORIES FROM INITIATION ZONES WOULD 
BE MOST FAVORABLE.

THE DRYING TREND WILL CONTINUE THROUGH THURSDAY AS YET ANOTHER 
CLOSED LOW/VORT MAX SPINS OFF THE WEST COAST...PROVIDING DEEP SWLY 
FLOW. TEMPERATURES WILL ALSO REMAIN WELL BELOW NORMAL DURING THIS 
PERIOD WITH H8 TEMPS +24C TO +28C AND H7 TEMPS +11C TO +14C. A 
GRADUAL INCREASE IN MOISTURE IS EXPECTED INTO THE WEEKEND AS THE 
FLOW BECOMES MORE EASTERLY AHEAD OF AN INVERTED TROUGH MOVING 
THROUGH MEXICO AND RIDGING ALOFT LIFTING TOWARDS THE FOUR CORNERS 
REGION. GIVEN THE UNCERTAINTY IN TIMING...POSITION...AND WESTWARD 
EXTENT OF THE MOISTURE SURGE...KEPT POPS IN A BELOW CLIMATOLOGY 
CATEGORY.

&&

.AVIATION... 
SOUTH CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL... ISOLATED TO 
POSSIBLY SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED BY LATE 
AFTERNOON AND INTO THE EVENING HOURS ACROSS SOUTH-CENTRAL ARIZONA. 
CU BASES ARE EXPECTED TO BE BETWEEN 6-8K FT WITH CIGS DROPPING DOWN 
TO 5K FT IN ANY THUNDERSTORMS. BY LATE EVENING...THE THREAT FOR ANY 
SHOWERS AND THUNDERSTORMS WILL QUICKLY DIMINISH.   

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
MOSTLY CLEAR SKIES TO CONTINUE THROUGH THE PERIOD...WITH SOME FEW TO 
SCATTERED CU AT AROUND 8K FT POSSIBLE AROUND KBLH THIS AFTERNOON 
INTO EARLY EVENING. WINDS WILL GENERALLY BE LIGHT AND OUT OF THE 
SOUTH.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
DRY CONDITIONS EARLY IN THE PERIOD WILL SEE INCREASING MOISTURE 
BEGINNING FRIDAY INTO THE WEEKEND. SHOWER AND THUNDERSTORM CHANCES 
WILL BE CONFINED TO THE EASTERN HIGH TERRAIN WEDNESDAY AND 
THURSDAY...BEFORE CHANCES SPREAD FURTHER WEST INTO THE SOUTH-CENTRAL 
ARIZONA LOWER DESERTS BEGINNING FRIDAY. MINIMUM HUMIDITIES WILL 
GENERALLY BE IN THE MID TEENS ACROSS THE LOWER DESERTS THROUGH 
SATURDAY BEFORE INCREASING INTO THE UPPER TEENS AND LOWER 20S BY 
NEXT SUNDAY. OVERALL...OVERNIGHT RECOVERIES WILL BE FAIR TO GOOD 
EACH NIGHT.   

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT

WEATHER.GOV/PHOENIX

DISCUSSION...HIRSCH/MO
AVIATION...KUHLMAN
FIRE WEATHER...KUHLMAN