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