999
FXUS65 KPSR 080523
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1023 PM MST FRI AUG 7 2026
UPDATE..UPDATED 06Z AVIATION DISCUSSION
KEY MESSAGES
- EXTREME HEAT WILL CONTINUE THROUGH THE WEEKEND, WITH AFTERNOON
HIGHS HOVERING NEAR TO SEVERAL DEGREES ABOVE NORMAL WHILE
HUMIDITY VALUES REMAIN HIGHER THAN NORMAL.
- SHOWER AND THUNDERSTORM ACTIVITY WILL BE MAINLY CONFINED TO
HIGHER TERRAIN AREAS OF SOUTHCENTRAL AZ THROUGH THIS WEEKEND
WITH GUSTY OUTFLOW WINDS AND BLOWING DUST THE MOST LIKELY
IMPACTS FOR THE LOWER DESERTS.
- MONSOON RAINFALL CHANCES BECOME MORE FAVORABLE AND WILL BEGIN TO
EXPAND INTO THE LOWER DESERTS BY LATE THIS WEEKEND AND INTO THE
START OF NEXT WEEK.
SHORT TERM /TODAY THROUGH SATURDAY/
LATEST VISIBLE SATELLITE IMAGERY INDICATES A GROWING CU FIELD
OVER THE MOGOLLON RIM AND WHITE MOUNTAINS AS WELL AS ACROSS
PORTIONS OF SOUTHEAST AZ. MESOANALYSIS INDICATES MLCAPE VALUES
INCREASING TO AROUND 1200-1500 J/KG OVER THE HIGHER TERRAIN OF
GILA COUNTY AND FAR E MARICOPA COUNTIES WHERE SKIES ARE CLEAR AND
SFC DEW POINTS ARE IN THE MID 50S TO LOWER 60S. HIGH-RES GUIDANCE
SUGGESTS STORMS CONTINUING TO DEVELOP OVER THE RIM AND PUSHING
INTO S GILA COUNTY BY EARLY THIS EVENING. WE WILL CONTINUE TO
MONITOR FOR A POTENTIAL OUTFLOW BOUNDARY THAT COULD SURGE INTO E
MARICOPA COUNTY, HOWEVER SUBSIDENCE ALOFT FROM A STRONG 596-598
DAM HIGH AND A STRONG CAPPING INVERSION (MLCIN -80 TO -100 J/KG)
WILL LIKELY LIMIT STORM ACTIVITY ACROSS THE LOWER DESERTS TONIGHT.
THEREFORE, POPS REMAIN ON THE ORDER OF 10-25% ACROSS MARICOPA AND
PINAL COUNTIES. IF ANY STORM DOES DEVELOP ALONG AN OUTFLOW
BOUNDARY, STRONG TO MARGINALLY SEVERE WIND GUSTS WILL BE POSSIBLE
WHICH COULD GENERATE AREAS OF BLOWING DUST. STORM CHANCES WILL
DIMINISH AFTER 06Z, LEADING TO A QUIET REST OF THE NIGHT. WITH THE
ADDITIONAL CLOUD COVER AND HIGHER DEW POINTS, OVERNIGHT LOWS WILL
REMAIN ABOVE NORMAL IN THE MID 80S TO AROUND 90 DEGREES.
EVEN THOUGH THE HIGH WILL REMAIN IN A FAVORABLE POSITION OVER THE 4-
CORNERS REGION FOR CONTINUED MONSOONAL ACTIVITY, HIGH PRESSURE ALOFT
WILL STRENGTHEN FURTHER ON SATURDAY. THIS WILL AGAIN PROVIDE A
STRONG SUBSIDENCE INVERSION OVER THE LOWER DESERTS. SLIGHTLY DRIER
AIR IS ALSO ANTICIPATED WITH SFC DEW POINTS FALLING INTO THE LOW TO
MID 50S. THESE CONDITIONS WILL LIKELY LIMIT STORM ACTIVITY ACROSS
THE LOWER DESERTS ASIDE FROM ANOTHER POTENTIAL OUTFLOW EMANATING
FROM CONVECTION OVER THE HIGH TERRAIN. NBM POPS DO APPEAR TO REFLECT
THIS SCENARIO AS RAIN CHANCES ARE VERY SIMILAR TO TODAY (10-20% FOR
THE LOWER DESERTS AND AROUND 30% OVER THE FOOTHILLS AND MOUNTAINS NE
OF PHOENIX).
THE UNSEASONABLY STRONG SUB-TROPICAL HIGH WILL CONTINUE TO REMAIN
ENTRENCHED OVER THE 4-CORNERS REGION THROUGH THIS WEEKEND WITH
500 MB HGHTS REMAINING AROUND 595-597 DAM THROUGH SUNDAY. HGHTS OF
THIS MAGNITUDE ARE IN THE 90TH-95TH PERCENTILE OF CLIMO FOR THIS
TIME OF YEAR. ALTHOUGH RECORD BREAKING TEMPERATURES ARE NOT
ANTICIPATED, AFTERNOON HIGHS WILL RUN A GOOD 4-8 DEGREES ABOVE
NORMAL FOR EARLY AUGUST, TRANSLATING TO READINGS RANGING NEAR
107-115 DEGREES. THESE TEMPERATURES WILL CONTINUE TO PROMOTE A
MODERATE TO MAJOR HEATRISK AND THUS AN EXTREME HEAT WARNING WILL
REMAIN IN EFFECT THROUGH THE REMAINDER OF THIS WEEKEND.
LONG TERM /SUNDAY THROUGH THURSDAY/
THE RELATIVE PAUSE IN CONVECTIVE ACTIVITY SHOULD BE FAIRLY SHORT
LIVED AS THE HIGH WILL EVENTUALLY BECOME PARKED OVER THE FOUR
CORNERS, INDUCING SOUTHEASTERLY FLOW OVER THE REGION WHICH SHOULD
PROVIDE RENEWED MOISTURE FLUX. POPS HAVE FALLEN SLIGHTLY COMPARED TO
24 HOURS AGO, MAINLY FOR LOWER ELEVATION AREAS, BUT THAT IS NOT MUCH
OF A SURPRISE AS IT MAKE TAKE A LITTLE BIT MORE TIME TO GET MOISTURE
PROFILES BACK TO MORE FAVORABLE LEVELS. THE MORE FAVORABLE SPOTS TO
SEE CONVECTION WILL ONCE AGAIN BE THE HIGH COUNTY AND SOUTHEAST
ARIZONA, BUT DOWNSTREAM EFFECTS FROM ANY ACTIVITY THAT DOES FORM
COULD HAVE IMPACTS ON OUR LOWER ELEVATION ZONES. ONCE WE GET
CLOSER, AND GET INSIDE THE HI-RES WINDOW, WE WILL HAVE A BETTER
IDEA ON WHAT IMPACTS TO EXPECT.
DAILY CHANCES FOR SHOWER AND THUNDERSTORMS WILL REACH INTO THE FRONT
HALF OF THE NEXT WORKWEEK AS SUFFICIENT MOISTURE STAYS IN PLACE. THE
LOWER DESERTS, IF NOT BY SUNDAY, MAY FINALLY GET IN ON SOME OF THE
ACTION AS LOW-LEVEL MOISTURE LOOKS TO IMPROVE WITH MODEL SOUNDINGS
INDICATING MIXING RATIOS REACHING 11-12 G/KG. THAT WILL AID IN
INCREASING INSTABILITY AND LIMITING THE CAP THAT HAS BEEN SO
PREVALENT THE PAST FEW DAYS. AS TYPICAL WITH THE MONSOON, HOW ONE
DAY PLAYS OUT WILL HEAVILY INFLUENCE WHAT HAPPENS THE SUBSEQUENT
DAY, SO DAY-TO-DAY FORECAST CHANGES SHOULD BE EXPECTED, BUT WITH
MOISTURE LEVELS NOT LIKELY TO FALL OFF THROUGH AT LEAST THE MIDDLE
PART OF THE WEEK, WE MAY BE LOOKING AT ONE OF THE MORE ACTIVE
PERIODS WE HAVE SEEN SO FAR THIS SUMMER.
TEMPERATURES WILL REMAIN SEVERAL DEGREES ABOVE SEASONAL LEVELS
THROUGH SUNDAY, BUT THERE APPEARS TO BE AT LEAST SOME RELIEF ON THE
HORIZON. WITH INCREASED MOISTURE, STORM COVERAGE, AND CLOUD COVER,
AFTERNOON HIGHS OVER SOUTH-CENTRAL ARIZONA ARE EXPECTED TO FALL MUCH
CLOSER TO NORMAL FOR THIS TIME OF YEAR WITH PROJECTED LOWER-DESERT
HIGHS BETWEEN 101-106 DEGREES BY TUESDAY. AREAS FURTHER DISPLACED
FROM THE STORM ACTIVITY, NAMELY SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA, WILL SEE TEMPERATURES GRADUALLY DECREASE TOO THANKS TO A
WEAKENING TREND WITH THE PREVAILING HIGH, BUT READINGS SHOULD REMAIN
SLIGHTLY HIGHER RELATIVE TO LOCATIONS FURTHER EAST. HIGHS FOR THOSE
WESTERN DESERT LOCATIONS WILL BE CLOSER TO 105-110 DEGREES THROUGH
AT LEAST THURSDAY.
AVIATION
UPDATED AT 0520Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
WINDS OVERNIGHT WILL FOLLOW TYPICAL DIURNAL TRENDS, TRANSITIONING
TO LIGHT EAST-SOUTHEAST AT KPHX AND KIWA, AND BECOMING LIGHT AND
VARIABLE AT KSDL AND KDVT. EXPECT A WESTERLY SHIFT BY LATE
SATURDAY MORNING TO EARLY AFTERNOON, WITH SPEEDS GENERALLY AROUND
8-12KTS AND OCCASIONAL AFTERNOON GUSTS NEAR 15-20KTS. MID TO HIGH
LEVEL CLOUD COVER SCT-BKN WILL THIN OVERNIGHT INTO SATURDAY
MORNING, BEFORE INCREASING AGAIN BY LATE SATURDAY AFTERNOON.
LOOKING AHEAD TO SATURDAY EVENING, CONVECTIVE OUTFLOW UNCERTAINTY
RETURNS TO THE FORECAST. MODEL GUIDANCE REMAINS HIGHLY DIVERGENT
REGARDING POTENTIAL STORM EVOLUTION AND BOUNDARY PROPAGATION,
THOUGH HIRES SOLUTIONS SUGGEST A POTENTIAL OUTFLOW PUSHING THROUGH
THE PHOENIX METRO AROUND THE 02-03Z TIMEFRAME. CONFIDENCE IN
TIMING, WIND DIRECTION, AND EXACT STRENGTH REMAINS LOW AT THIS
TIME, BUT SOLUTIONS ARE POINTING TO WINDS EMANATING FROM THE
NORTH- NORTHEAST.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR AVIATION CONCERNS EXPECTED THROUGH THE TAF PERIOD. AT
KIPL, SOUTHEASTERLY WINDS WILL SHIFT WESTERLY OVERNIGHT BEFORE
RETURNING TO A SOUTHEASTERLY DIRECTION BY LATE SATURDAY MORNING.
AT KBLH, WINDS WILL MAINTAIN A S TO WSW DIRECTION THROUGHOUT THE
PERIOD. SPEEDS AT BOTH TERMINALS WILL REMAIN LIGHT, GENERALLY
UNDER 10KTS. SKY CONDITIONS WILL FEATURE MOSTLY CLEAR SKIES
OVERNIGHT WITH FEW HIGH CLOUDS RETURNING DURING THE DAY ON
SATURDAY.
FIRE WEATHER
HOT TEMPERATURES WITH ELEVATED HUMIDITY LEVELS WILL CONTINUE THROUGH
THE WEEKEND. ALTHOUGH HUMIDITY LEVELS WILL TREND DOWN, REGIONAL
READINGS SHOULD REMAIN AT 15% OR ABOVE THROUGH SATURDAY, AND
INCREASE BACK TO AROUND 20% OR GREATER ON SUNDAY. OVERNIGHT RECOVERY
WILL OFFER MODEST TO DECENT RELIEF AS MAXRHS RANGE GENERALLY BETWEEN
30-55% THROUGH SUNDAY, WITH EVEN BETTER READINGS EXPECTED BY EARLY
NEXT WEEK. RAIN CHANCES THROUGH SATURDAY WILL BE MOSTLY CONFINED TO
HIGH TERRAIN AREAS AND SOUTHEASTERN ARIZONA, WITH LOWER DESERT
CHANCES REMAINING 15% OR BELOW. BY SUNDAY, INCREASING MOISTURE WILL
RESULT IN AN UPTREND IN LOWER ELEVATION SHOWER AND THUNDERSTORM
CHANCES, WHICH APPEARS LIKELY TO PERSIST INTO THE FOLLOWING WEEK.
OUTSIDE OF THUNDERSTORM OUTFLOWS, WINDS WILL FOLLOW FAMILIAR DIURNAL
TRENDS, WITH TYPICAL AFTERNOON UPSLOPE BREEZINESS AROUND 20 MPH.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...EXTREME HEAT WARNING UNTIL 8 PM MST SUNDAY FOR AZZ530>544-546-
548>551-553>555-559.
CA...EXTREME HEAT WARNING UNTIL 8 PM PDT SUNDAY FOR CAZ560>570.
SHORT TERM...SALERNO
LONG TERM...RW
AVIATION...95
FIRE WEATHER...RW/SALERNO
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