609
FXUS65 KPSR 111848
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1148 AM MST TUE AUG 11 2026
KEY MESSAGES
- BETTER MOISTURE AND MORE FAVORABLE CONDITIONS FOR MONSOON STORM
DEVELOPMENT IS EXPECTED THROUGH MIDWEEK WITH THE MOST WIDESPREAD
ACTIVITY ACROSS SOUTH-CENTRAL AND EASTERN ARIZONA.
- LOCALLY HEAVY RAINFALL AND GUSTY THUNDERSTORM WINDS WILL REMAIN
POSSIBLE THROUGH THURSDAY BEFORE DRYING CONDITIONS ENDS RAIN
CHANCES AS EARLY AS FRIDAY.
- COOLING TEMPERATURES ARE EXPECTED THROUGH MIDWEEK, BRIEFLY
FALLING TO BELOW NORMAL WEDNESDAY THROUGH FRIDAY.
SHORT TERM /TODAY THROUGH THURSDAY/
GOES MID-LEVEL WV IMAGERY AND RAP40 500MB ANALYSIS CONTINUE TO
SHOW THE UPPER LEVEL PATTERN WITH SOUTHEASTERLY FLOW ALOFT AND
THE CORE OF THE HIGH PRESSURE OVER THE FOUR CORNERS REGION. BY
WEDNESDAY THE HIGH WILL BE PUSHED EASTWARDS TOWARDS TEXAS WHILE A
TROUGH DEEPENS ACROSS THE WESTERN COAST, AND IS EXPECTED TO
REMAIN IN PLACE THROUGH THE END OF THE WEEK, BRINGING
SOUTHWESTERLY FLOW ALOFT. THIS WILL HELP GRADUALLY DRY THE REGION
OUT ESPECIALLY TOWARDS THE LATER HALF OF THE WEEK AND HEADING
INTO THE WEEKEND. OTHERWISE FOR THE REST OF TODAY, A MOSTLY
OVERTURNED ATMOSPHERE FROM THE PAST ACTIVE NIGHTS WILL LIKELY TO
LIMIT SHOWER AND THUNDERSTORM ACTIVITY COMPARED TO THE LAST COUPLE
OF DAYS. HREF SHOWS A 30-50% CHANCE OF STORM DEVELOPMENT IN THE
EASTERN HIGH TERRAIN WITH ONLY A 10-20% CHANCE OF ACTIVITY
DEVELOPING TONIGHT AND INTO THE OVERNIGHT PERIOD FOR THE LOWER
DESERTS. THAT BEING SAID THE MAIN IMPACT/CONCERN FOR THE LOWER
DESERTS WILL BE BREEZY TO WINDY CONDITIONS FROM OUTFLOWS, THATS IF
THEY CAN SURVIVE INTO THE LOWER DESERTS.
UNCERTAINTY REMAINS HIGH FOR WEDNESDAY AS THE WEAK TROUGH BEGINS
TO ENTER WESTERN PORTIONS OF THE REGION TURNING THE FLOW OUT OF
THE SOUTH SOUTHWEST. THE INCOMING TROUGH IS EXPECTED TO INCREASE
UPPER LEVEL FORCING ACROSS MUCH OF THE AREA FOR WEDNESDAY INTO
EARLY THURSDAY, BUT AS THE FLOW SHIFTS OUT OF THE SOUTH SOUTHWEST
SOME DRY AIR WILL BEGIN TO FILTER INTO WESTERN AND THEN SOUTH-
CENTRAL ARIZONA. HOWEVER, PLENTY OF MOISTURE WILL REMAIN FROM
AROUND PHOENIX AND AREAS TO THE EAST AND NORTHEAST OF PHOENIX. THE
BIGGEST QUESTION WILL BE THE AREAS OF FOCUS FOR SHOWER AND STORMS
FROM WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING. GUIDANCE
INDICATES THE BEST CHANCES FROM NORTHERN AND EASTERN PORTIONS OF
PHOENIX INTO THE HIGHER TERRAIN WITH POPS OF 50-70% WITH
DECREASING CHANCES TO THE SOUTH AND WEST AS THAT DRIER AIR ENTERS
THE REGION. A FASTER THAN NORMAL STORM MOVEMENT SHOULD HELP TO
LIMIT THE HEAVY RAINFALL THREAT, BUT THE AFOREMENTIONED FACTORS
COULD STILL LEAD TO SOME INSTANCES OF FLASH FLOODING, ESPECIALLY
IN NE AZ. THE ACTIVITY IS LIKELY TO PERSIST DURING THE OVERNIGHT
HOURS/THURSDAY MORNING, BUT THE THREAT FOR HEAVY RAINFALL IS
LIKELY TO GRADUALLY DECREASE.
THE GOOD NEWS, OUTSIDE OF PRECIPITATION POTENTIAL, WILL BE THAT
THIS ACTIVITY WILL LEAD TO AMPLE CLOUD COVERAGE OVER THE NEXT FEW
DAYS, HELPING TEMPERATURES TO BE NEAR NORMAL TODAY, THEN 3F-6F
DEGREES BELOW NORMAL STARTING WEDNESDAY. THIS WILL LEAD TO A LARGE
MAJORITY OF THE REGION DROPPING TO MINOR HEATRISK WITH THE
EXCEPTION OF A SMALL CORNER OF SE CA, WHERE LOCALIZED AREAS OF
MODERATE WILL REMAIN. ADDITIONALLY THE MORNING LOW TEMPERATURES
WILL CONTINUE TO BE NEAR TO SLIGHTLY BELOW NORMAL THROUGH OUT THE
REST OF THE WORK WEEK.
LONG TERM /FRIDAY THROUGH MONDAY/
DRYING IS EXPECTED TO PICK UP ACROSS THE AREA DURING THE LATTER
HALF OF THURSDAY WITH MOST OF THE SHOWER AND THUNDERSTORM
POTENTIAL SHIFTING TO OVER THE ARIZONA HIGH TERRAIN. BY FRIDAY,
ENOUGH DRY AIR IS EXPECTED TO FILTER INTO THE AREA TO COMPLETELY
END RAIN CHANCES ACROSS THE LOWER DESERTS WHILE LIMITED CHANCES
ARE FORECAST FOR THE HIGH TERRAIN. THE SUBTROPICAL HIGH IS
EXPECTED TO STAY CENTERED ACROSS THE SOUTHEASTERN U.S. THROUGH AT
LEAST THE WEEKEND WITH BROAD TROUGHING OVER MUCH OF THE WESTERN
U.S. THIS WILL KEEP DRY AIR IN PLACE THROUGH AT LEAST THE UPCOMING
WEEKEND WITH AT MOST SLIGHT CHANCES FOR AFTERNOON CONVECTION OVER
THE FAR EASTERN ARIZONA HIGH TERRAIN. ENSEMBLES DO SHOW THE
SUBTROPICAL HIGH BECOMING MORE ELONGATED LATE THIS WEEKEND WITH
HEIGHTS GRADUALLY INCREASING OVER OUR REGION. AS A RESULT,
TEMPERATURES ARE LIKELY TO CLIMB BACK TO AROUND OR EVEN A FEW
DEGREES ABOVE NORMAL BY SUNDAY OR MONDAY. THE NEXT POTENTIAL FOR
RAIN COULD COME AS EARLY AS NEXT MONDAY OR TUESDAY, BUT
UNCERTAINTY IS QUITE HIGH AT A WEEK AWAY.
AVIATION
UPDATED AT 1835Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
WEST WINDS WILL CONTINUE INTO THE OVERNIGHT HOURS. GUSTS INTO THE
UPPER TEENS TO AROUND 20 KT IS EXPECTED DURING THE AFTERNOON AND
EARLY EVENING HOURS. A DISTANT OUTFLOW FROM THE NE MAY AFFECT THE
PHOENIX AIRSPACE DURING THE EVENING (02-05Z TIMEFRAME), BUT
CONFIDENCE IS TOO LOW FOR TAF INCLUSION AT THIS TIME. THEN, A
SECOND DISTANT OUTFLOW MAY REACH THE TERMINALS LATE EVENING INTO
THE OVERNIGHT HOURS OUT OF THE SE, CONFIDENCE FOR THIS OUTFLOW IS
ALSO TOO LOW TO INCLUDE IN THE TAF AT THIS TIME. ANOTHER PERIOD OF
VCSH/VCTS WILL NEED TO BE EVALUATED FOR THE OVERNIGHT PERIOD INTO
WEDNESDAY MORNING, WITH 20-30% CHANCES FOR SPOTTY COVERAGE OF
SHRA/TS ACROSS THE PHOENIX AIRSPACE. WINDS TOMORROW MORNING ARE
EXPECTED TO BE SIMILAR TO THIS MORNING AT KPHX WITH AN EARLIER
SHIFT TO WESTERLY AROUND 15Z AT KPHX AND KIWA.LOWEST CLOUD BASES
WILL MOSTLY STAY AT OR ABOVE 10K FT AGL THROUGH THE PERIOD.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
THE POTENTIAL FOR STRONG OUTFLOW WINDS TO ONCE AGAIN REACH THE
TERMINALS AND VCSH/VCTS CONDITIONS THIS AFTERNOON WILL BE THE
PRIMARY AVIATION WEATHER CONCERNS. WINDS WILL FAVOR A SOUTHERLY
DIRECTION AT KBLH WITH AFTERNOON GUSTS TO AROUND 20 KTS. VCSH/VCTS
MAY DEVELOP AT KBLH TUESDAY AFTERNOON BEGINNING AROUND 22Z. AT
KIPL, WINDS WILL PRIMARILY FAVOR S-SE THROUGH THE TAF PERIOD, WITH
A PERIOD OF W-SW LATER TUESDAY AFTERNOON AND EVENING ASSOCIATED
WITH STORM OUTFLOW AND VCSH/VCTS. VCSH/VCTS MAY DEVELOP AT KIPL
TUESDAY AFTERNOON BEGINNING AROUND 00Z. STRONG GUSTY AND ERRATIC
WINDS ARE ALSO POSSIBLE WITH ANY OUTFLOWS. FEW TO SCT CLOUDS WILL
BE COMMON OVER THE AREA WITH LOWEST BASES DOWN TO AROUND 10K FT
AGL.
FIRE WEATHER
SCATTERED SHOWERS AND THUNDERSTORMS ARE ANTICIPATED EACH DAY
THROUGH MIDWEEK ACROSS THE HIGHER TERRAIN AREAS OF THE EASTERN
DISTRICTS, WITH SLIGHTLY LOWER CHANCES IN THE LOWER ELEVATIONS.
THE BEST CHANCES WILL FALL DURING THE LATTER HALF OF WEDNESDAY
INTO THURSDAY MORNING. AFTERNOON MINRHS WILL RANGE BETWEEN 25-35%
IN THE LOWER DESERTS AND BETWEEN 40-50% IN THE EASTERN HIGH
TERRAIN THROUGH WEDNESDAY WITH GOOD TO EXCELLENT OVERNIGHT
RECOVERIES. ASIDE FROM GUSTY AND ERRATIC WINDS NEAR THUNDERSTORMS,
THE OVERALL WIND PATTERN WILL FOLLOW THE DIURNAL TRENDS WITH
MODEST AFTERNOON UPSLOPE GUSTS. NEAR TO BELOW NORMAL TEMPERATURES
ARE EXPECTED THROUGH THE REST OF THE WEEK WITH DRYING CONDITIONS
BY FRIDAY AND LASTING THROUGH NEXT WEEKEND.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...RYAN/KUHLMAN
LONG TERM...KUHLMAN
AVIATION...RYAN/WHITTOCK
FIRE WEATHER...KUHLMAN
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