436
FXUS65 KPSR 082005
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
105 PM MST WED JUL 8 2026
KEY MESSAGES
- HOT TEMPERATURES WILL CONTINUE THIS WEEK RESULTING IN AREAS OF
MAJOR HEAT RISK AND EXTREME HEAT WARNINGS THROUGH THURSDAY ACROSS
LOWER DESERT LOCATIONS.
- CHANCES FOR SHOWERS AND THUNDERSTORMS WILL CONTINUE OVER HIGHER
TERRAIN AREAS OF EASTERN ARIZONA TODAY AND TO A LESSER EXTENT
THURSDAY AND FRIDAY.
- THE WEATHER PATTERN WILL BECOME VERY FAVORABLE FOR MOISTURE IMPORT
AND MORE WIDESPREAD THUNDERSTORM ACTIVITY BY EARLY NEXT WEEK.
SHORT TERM /TODAY THROUGH FRIDAY/
ELONGATED SUBTROPICAL RIDGING IN A RETROGRESSIVE PHASE CONTINUES TO
BE THE DOMINANT FEATURE ACROSS THE SW CONUS WITH TWIN 596DM H5 ANTI-
CYCLONE CENTERS OVER NE ARIZONA AND JUST OFF THE SOUTHERN CALIFORNIA
COAST RESPECTIVELY. THIS RETROGRESSION WILL PERSIST THE NEXT 48
HOURS AS SHORTWAVE ENERGY AND WESTERLY JET ENERGY BREAK OVER THE
RIDGE INTO THE GREAT BASIN. THIS EVOLUTION WILL ALSO ACT TO DAMPEN
MIDTROPOSPHERIC HEIGHTS WITH H5 LEVELS FALLING CLOSER TO 592-594DM
BY FRIDAY BEFORE THE HIGH PRESSURE CENTER BUILDS BACK NORTHEAST
BEHIND THE DEPARTING NORTHERN STREAM SHORTWAVE. DESPITE THESE SUBTLE
SHIFTS IN POSITIONING AND INTENSITY, CONFIDENCE IS EXCELLENT THAT
TEMPERATURES 5F-10F ABOVE NORMAL WILL BE COMMON ACROSS THE REGION
THE NEXT SEVERAL DAYS WITH TODAY AND THURSDAY THE HOTTEST DAYS. WITH
AREAS OF MAJOR HEATRISK PERSISTING, EXTREME HEAT WARNINGS CONTINUE
THROUGH THURSDAY, AND MAY NEED A SMALL EXPANSION IN FUTURE FORECASTS
ACROSS PARTS OF SE CALIFORNIA FRIDAY JUXTAPOSED WITH THE CORE OF THE
HIGH PRESSURE CENTER.
OBJECTIVE ANALYSIS INDICATES A MARKED INCREASE IN MOISTURE ACROSS
MUCH OF SOUTH-CENTRAL ARIZONA SINCE YESTERDAY WITH 7-9 G/KG LOW
LEVEL MIXING RATIOS ENVELOPING MOST OF THE ARIZONA CWA WITH TOTAL
COLUMN PWATS IN EXCESS OF 1.00". FARTHER SOUTH CLOSER TO THE
INTERNATIONAL BORDER, MIXING RATIOS 10-11 G/KG, H8 DEWPOINTS GREATER
THAN 10C, AND PWATS NEAR 1.50" WERE ANALYZED, THOUGH THIS MORE
THERMODYNAMICALLY FAVORABLE AIRMASS WILL ONLY BE TRANSPORTED NORTH
WITH AID OF STRONG OUTFLOW BOUNDARIES. WITH BETTER INSTABILITY IN
PLACE AND VERY FAVORABLE STRETCHING AND DIVERGENCE ALOFT, MOUNTAIN
STORMS OVER GILA COUNTY SHOULD BE MORE ROBUST THIS AFTERNOON WITH
DCAPE BETTER THAN 1500 J/KG PROMOTING STRONG OUTFLOW BOUNDARIES.
ADDITIONAL OUTFLOWS FROM CONVECTION OVER SOUTHERN ARIZONA MAY ALSO
SURGE NORTH INTO THE FORECAST AREA THIS EVENING IMPORTING ADDITIONAL
MOISTURE TO THE AREA. WHILE COLLIDING OUTFLOW BOUNDARIES WOULD BE
BENEFICIAL FOR NEW THUNDERSTORM DEVELOPMENT OVER LOWER ELEVATIONS,
FORECAST SOUNDINGS AND HREF OUTPUT ARE NOT PARTICULARLY BULLISH ON
THIS OUTCOME, AND HAVE MAINTAINED POPS UNDER 10% (THOUGH NOT
IMPOSSIBLE FOR AN ISOLATED STORM TO ERUPT THIS EVENING GIVEN THE
OTHERWISE EXCELLENT SYNOPTIC SETUP).
THUNDERSTORM COVERAGE AND IMPACTS WILL DECREASE THURSDAY AND FRIDAY
AS THE AFOREMENTIONED UPPER JET PROGRESSING THROUGH THE GREAT BASIN
IMPARTS GREATER SUBSIDENCE AND MIDLEVEL WARMING INTO THE CWA WHILE
SHIFTING THE BETTER SYNOPTICS TOWARDS THE INTERNATIONAL BORDER.
ISOLATED STORMS ARE STILL POSSIBLE OVER MOUNTAINS OF EASTERN ARIZONA
(AND CERTAINLY INTO SOUTHERN ARIZONA), HOWEVER DESPITE NEAR STEADY
STATE MOISTURE PROFILES, STRONGER INHIBITION OVER LOWER ELEVATIONS
AND LACK OF EFFECTIVE BOUNDARIES SHOULD PRECLUDE ANY NOTABLE STORM
CHANCES. HOWEVER, THERE IS CONVINCING EVIDENCE FROM MODEL OUTPUT
THAT A LARGE CONVECTIVE COMPLEX OVER NORTHERN SONORA FRIDAY EVENING
WILL SEND A POOL OF GREATER THETA-E INTO CENTRAL ARIZONA WITH MIXING
RATIOS ABOVE 10 G/KG AND PWATS NEAR 1.50" SETTING THE STAGE FOR A
MORE CONVECTIVELY ACTIVE PERIOD OF THE MONSOON OVER THE WEEKEND AND
NEXT WEEK.
LONG TERM /SATURDAY THROUGH TUESDAY/
THE WEATHER PATTERN WILL UNDERGO A NOTICEABLE SHIFT THROUGH THE
WEEKEND AS THE HIGH PRESSURE RIDGE QUICKLY TRACKS NORTHEASTWARD WITH
THE CENTER REACHING UTAH SATURDAY. THE RIDGE IS THEN FORECAST TO
EXPAND, STRENGTHEN, AND BECOME THE MAIN DRIVER OF STRONG MOISTURE
ADVECTION BACK INTO THE DESERT SOUTHWEST NEXT WEEK. AS THE HIGH
CENTER FINALLY SHIFTS TO OUR NORTH INTO SATURDAY, IT SHOULD FIRST
OPEN UP EASTERN AND SOUTHERN ARIZONA TO AN EASTERLY MOISTURE FETCH.
MOISTURE IS STILL LIKELY TO BE FAIRLY LIMITED ON SATURDAY WITH
AFTERNOON CONVECTION CURRENTLY FAVORED MORE ACROSS SOUTHEAST
ARIZONA, BUT ONCE THE STEERING FLOW SHIFTS OUT OF THE EAST MOISTURE
ADVECTION AND STORM CHANCES ARE EXPECTED TO SPREAD WESTWARD THROUGH
THE REST OF ARIZONA STARTING SUNDAY.
ALTHOUGH FORECAST UNCERTAINTY REMAINS FAIRLY HIGH GOING INTO NEXT
WEEK, ENSEMBLES GENERALLY AGREE WE WILL ENTER A PERIOD OF ACTIVE
MONSOON WEATHER. THE SUBTROPICAL HIGH IS FAVORED TO STAY POSITIONED
OVER THE NORTHERN PLAINS INTO THE CENTRAL ROCKIES FOR MUCH OF NEXT
WEEK WHICH WILL ALLOW FOR FAIRLY PERSISTENT MOIST EASTERLY FLOW INTO
THE DESERT SOUTHWEST. ENSEMBLE MEMBER FORECAST PWATS SHOW A WIDE
SPREAD, BUT ALSO A MEANINGFUL AVERAGE INCREASE LIKELY PUSHING PAST
1.3-1.4" STARTING SUNDAY. FORECAST POPS INCREASE INTO A 20-40% RANGE
STARTING SUNDAY AND GENERALLY STAY THERE THROUGH THE FIRST HALF OF
NEXT WEEK. ANY NOTABLE EASTERLY WAVES MOVING THROUGH THE FLOW WILL
SURELY HELP DRIVE OUR CONVECTIVE POTENTIAL, BUT PINPOINTING THOSE
THIS FAR OUT IS A DUBIOUS PROPOSITION. OUTSIDE OF THE EXPECTED
INCREASE IN MONSOON STORM ACTIVITY, TEMPERATURES SHOULD SLIP FURTHER
TOWARD SEASONAL NORMALS.
AVIATION
UPDATED AT 1730Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
BREEZY OUTFLOW WINDS DURING THE EVENING WILL BE THE MAIN AVIATION
CONCERN DURING THE TAF PERIOD. BEST TIMING TO SEE A SUDDEN SWITCH
OUT OF THE E/SE FROM ONE OF THESE BOUNDARIES LOOKS TO BE BETWEEN 02-
04Z, WITH GUSTS 20-25 KT IN ACCOMPANIMENT. IN THE MEANTIME, W'RLY
WINDS WILL PREVAIL THROUGH THE AFTERNOON, WITH TYPICAL GUSTS IN THE
MID-TEENS TO AROUND 20 KT. THE E'RLY TURN MENTIONED ABOVE WITH THE
EVENING OUTFLOW WILL STICK THROUGH THURSDAY MORNING. OTHER THAN
DISTANT CONVECTIVE CU OVER EASTERN ARIZONA, SKIES AROUND THE
TERMINALS WILL BE MOSTLY CLEAR.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR AVIATION CONCERNS ARE EXPECTED DURING THE NEXT 24 HOURS.
WINDS AT KIPL WILL GENERALLY BE OUT OF THE SE, WITH PERHAPS A VERY
BRIEF SWITCH OUT OF THE SW THIS EVENING. AT BLH, FAMILIAR DIURNAL
TRENDS WILL PREVAIL AS WINDS SWING BETWEEN SSE AND SW, WITH GUSTS
THIS AFTERNOON AROUND 20-25 KT. PERIODS OF VRB CONDITIONS MAY ALSO
BE OBSERVED DURING THE NIGHTTIME HOURS, ESPECIALLY AT KIPL. CLEAR
SKIES WILL BE COMMON ACROSS THE REGION THROUGH THURSDAY.
FIRE WEATHER
GUSTY AND ERRATIC THUNDERSTORM WINDS WITH ISOLATED LIGHTNING OVER
THE FAR EASTERN DISTRICTS THE NEXT FEW AFTERNOONS WILL BE THE MAIN
FIRE WEATHER CONCERN. OUTSIDE OF ANY POTENTIAL OUTFLOWS, WINDS
SHOULD FAVOR LIGHT AND DIURNAL TRENDS WITH TYPICAL AFTERNOON
BREEZINESS AROUND 20 MPH. AFTERNOON RH VALUES BETWEEN 10-15% WILL BE
COMMON ACROSS THE REGION. OVERNIGHT RECOVERIES WILL OFFER ONLY
LIMITED TO MODEST RELIEF AS MAXRH VALUES RANGE GENERALLY BETWEEN 20-
45%. TEMPERATURES ARE EXPECTED TO RUN WELL ABOVE NORMAL THROUGH THE
MIDDLE OF THE WEEK, WITH THE LOWEST ELEVATIONS REACHING BETWEEN 110-
115 DEGREES. A DECREASE IN MONSOON ACTIVITY IS LIKELY LATE WEEK,
BEFORE PICKING UP AGAIN AND BECOMING MORE WIDESPREAD BY EARLY NEXT
WEEK. MOISTURE LEVELS AND HUMIDITIES SHOULD ALSO IMPROVE
CONSIDERABLY BY EARLY NEXT WEEK, ALLEVIATING MUCH OF THE FIRE
WEATHER CONCERNS.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...EXTREME HEAT WARNING UNTIL 8 PM MST THURSDAY FOR AZZ530>534-
536>551-553>555-559-560-562.
CA...EXTREME HEAT WARNING UNTIL 8 PM PDT THURSDAY FOR CAZ562-564>570.
SHORT TERM...18
LONG TERM...KUHLMAN
AVIATION...RW
FIRE WEATHER...KUHLMAN
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