893
FXUS65 KPSR 101048
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
348 AM MST MON AUG 10 2026
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- EXTREME HEAT WARNINGS ARE IN EFFECT THROUGH THIS EVENING FOR WESTERN
IMPERIAL COUNTY AS WELL AS ALONG THE LOWER COLORADO RIVER
VALLEY AS HEAT INDICES ARE FORECAST TO PEAK BETWEEN 110 AND 120
DEGREES.
- DEEPER MOISTURE WILL PROVIDE FAVORABLE CONDITIONS FOR DAILY
SHOWER AND THUNDERSTORM ACTIVITY TO MATERIALIZE ACROSS THE AREA
THROUGH THE MIDDLE OF THE WEEK, ALONG WITH NOTICEABLY COOLER
TEMPERATURES.
- THUNDERSTORM CHANCES WILL DECREASE NOTICEABLY BY THE END OF THE WEEK
INTO NEXT WEEKEND AS DRIER AIR FILTERS IN.
SHORT TERM /TODAY THROUGH TUESDAY/
A VERY ACTIVE EVENING WAS OBSERVED ACROSS MUCH OF SOUTH-CENTRAL AZ
AS STRONG TO SEVERE THUNDERSTORMS DEVELOPED AND IMPACTED NEAR I-8
BETWEEN CASA GRANDE AND GILA BEND AS WELL AS ACROSS PORTIONS OF THE
PHOENIX AREA, ESPECIALLY FROM CENTRAL PHOENIX WESTWARD THROUGH THE
PHOENIX WEST VALLEY. PEAK WIND GUSTS WITH THESE STORMS TOPPED
ANYWHERE BETWEEN 60-80 MPH. ACTIVITY GRADUALLY DRIFTED WESTWARD
INTO WESTERN MARICOPA THROUGH LA PAZ COUNTIES WHILE GRADUALLY
WEAKENING IN THE PROCESS. GIVEN THE VERY ACTIVE EVENING THAT WAS
OBSERVED AND WITH THE ATMOSPHERE OVER-WORKED SOMEWHAT, THE
FORECAST FOR LATER TODAY IS HIGHLY UNCERTAIN IN TERMS OF OVERALL
STORM COVERAGE AS IT WILL BE HIGHLY CONDITIONAL ON HOW FAST THE
ATMOSPHERE CAN RECOVER. HOWEVER, IF THE ATMOSPHERE CAN RECOVER
FAST ENOUGH, THEN THERE IS THE POTENTIAL THAT LATE THIS AFTERNOON
THROUGH THIS EVENING CONDITIONS COULD TURN ACTIVE ONCE AGAIN,
ESPECIALLY SINCE THERE ARE INDICATIONS FROM THE GUIDANCE OF A MID-
LEVEL SHORTWAVE TROUGH MOVING THROUGH THE REGION AND COULD
ENHANCE THE CONVECTIVE ACTIVITY. EAST TO SOUTHEAST MID-LEVEL FLOW
ALONG THE SOUTHERN PERIPHERY OF THE SUBTROPICAL HIGH LOCATED NEAR
THE FOUR-CORNERS REGION WILL CONTINUE TO TRANSPORT HIGHER MOISTURE
CONTENT AS PWATS ARE PROJECTED TO INCREASE TO AROUND 1.5" WITH
MLCAPE VALUES PEAKING AT AROUND 1000 J/KG. MOST OF THE HI-RES
GUIDANCE FOR LATER THIS AFTERNOON THROUGH THIS EVENING SHOW STORMS
DEVELOPING ACROSS THE MOGOLLON RIM AND WHITE MOUNTAINS AS WELL AS
ACROSS SOUTHEAST AZ AND GRADUALLY DRIFTING WESTWARD INTO THE
LOWER DESERTS OF SOUTH-CENTRAL AND SOUTHERN AZ. WITH DCAPE VALUES
PEAKING AT AROUND 1500 J/KG, STRONG OUTFLOWS WILL ONCE AGAIN BE A
THREAT WITH THE POTENTIAL, SIMILAR TO LAST NIGHT, THAT THESE
OUTFLOWS COULD SPARK NEW STORM DEVELOPMENT IN THE LOWER DESERTS OF
SOUTH-CENTRAL AZ, INCLUDING FOR PORTIONS OF THE PHOENIX AREA,
WITH STRONG DOWNBURST WIND GUSTS AND LOCALLY HEAVY RAINFALL BEING
THE MAIN HAZARDS. THERE WILL ALSO BE A POTENTIAL FOR AREAS OF
BLOWING DUST TO MATERIALIZE AS WELL IN THE DUST PRONE AREAS. THE
ENVIRONMENTAL CONDITIONS WILL NOT CHANGE THAT MUCH FOR TUESDAY SO
THE THREAT FOR ADDITIONAL STORMS WILL CONTINUE, ESPECIALLY ACROSS
THE HIGHER TERRAIN AREAS. HOWEVER, IF THIS EVENING TURNS OUT TO
BE ACTIVE ACROSS THE LOWER DESERTS, THEN TUESDAY COULD TURN OUT TO
BE MORE OF A DOWN DAY FOR THE LOWER DESERTS.
AFTERNOON HIGH TEMPERATURES TODAY WILL RANGE BETWEEN 105-110 DEGREES
ACROSS THE LOWER DESERTS, ENOUGH TO CAUSE THE HEATRISK LEVELS TO
DROP BACK INTO THE MODERATE CATEGORY. ACROSS THE WESTERN HALF OF
IMPERIAL COUNTY AND ALONG THE LOWER COLORADO RIVER VALLEY, WITH
DEWPOINTS EXPECTED TO RANGE FROM THE MID 60S TO LOW 70S, WITH THE
HIGHEST DEWPOINTS ALONG THE IMPERIAL VALLEY, HEAT INDICES ARE
EXPECTED TO PEAK BETWEEN 110-120 DEGREES LATER THIS MORNING INTO
THIS AFTERNOON. THEREFORE, GIVEN THESE HIGH HEAT INDICES, AN
EXTREME HEAT WARNING IS IN EFFECT FOR THIS REGION THROUGH THIS
EVENING. TEMPERATURES ON TUESDAY WILL COOL BY AN ADDITIONAL 2-4
DEGREES WITH AFTERNOON HIGHS NEAR SEASONAL LEVELS.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
MODEL GUIDANCE CONTINUES TO BE CONSISTENT IN INDICATING ANOTHER MORE
ACTIVE PERIOD MATERIALIZING WEDNESDAY INTO THE FIRST HALF OF
THURSDAY. THE FLOW BY WEDNESDAY IS FORECAST TO SHIFT OUT OF THE
SOUTH AS THE SUBTROPICAL HIGH SHIFTS INTO TEXAS AND A UPPER-LEVEL
LOW MEANDERS OFF THE CALIFORNIA COAST. THIS SOUTHERLY FLOW IS LIKELY
TO BRING ADDITIONAL MOISTURE NORTHWARD FROM MEXICO, WITH PROJECTED
PWATS INCREASING TO 1.7-2.0" AND LOW-LEVEL MIXING RATIOS INCREASING
TO 12-13 G/KG. IN ADDITION, THERE WILL LIKELY MORE FAVORABLE UPPER-
LEVEL FORCING FROM THE AFOREMENTIONED UPPER-LEVEL LOW IN THE FORM OF
DIVERGENCE ALOFT AS WELL AS THE POTENTIAL OF AN EASTERLY WAVE MOVING
INTO THE REGION FROM MEXICO AS INDICATED BY BOTH THE GFS AND ECMWF.
THE MORE FAVORABLE UPPER-LEVEL FORCING IS LIKELY TO ENHANCE THE
CONVECTIVE ACTIVITY, WITH FLASH FLOODING BECOMING MORE OF A THREAT
GIVEN THE DEEPER MOISTURE PROFILES THAT WILL BE IN PLACE. THE LATEST
NBM POPS FOR WEDNESDAY THROUGH THE FIRST HALF OF THURSDAY REMAIN
ELEVATED, RANGING BETWEEN 40-60% ACROSS MUCH OF SOUTH-CENTRAL AND
SOUTHEAST AZ.
HEADING TOWARDS THE END OF THE WEEK AND NEXT WEEKEND, THE GUIDANCE
IS IN GOOD AGREEMENT IN SHOWING THE SUBTROPICAL HIGH RELOCATING
TOWARDS THE GULF COAST REGION WHILE THE AFOREMENTIONED UPPER-
LEVEL LOW REMAINS SITUATED OFF THE WEST COAST. THIS PATTERN
CONFIGURATION WILL CAUSE THE FLOW TO SHIFT MORE OUT OF THE
SOUTHWEST, BRINGING IN A DRIER AIRMASS AS PWATS DROP UNDER
1.2-1.3". AS A RESULT, AN OVERALL DOWNTREND IN THUNDERSTORM
ACTIVITY IS EXPECTED, WITH AFTERNOON ACTIVITY LIMITED TO THE
EASTERN THIRD OF AZ.
TEMPERATURES DURING THE MIDDLE TO LATTER HALF OF THE WEEK WILL RUN
SLIGHTLY BELOW NORMAL AS AFTERNOON HIGHS WILL TOP OUT IN THE LOW
100S ACROSS THE SOUTH-CENTRAL AZ LOWER DESERTS TO THE MID 100S
ACROSS THE WESTERN DESERTS. IN FACT, WITH THE POTENTIAL FOR ABUNDANT
CLOUD COVER AS WELL AS LINGERING RAINFALL ACTIVITY, AFTERNOON HIGHS
ON THURSDAY MAY STRUGGLE TO REACH THE TRIPLE DIGITS ACROSS THE SOUTH-
CENTRAL AZ LOWER DESERTS. TEMPERATURES WILL GRADUALLY REBOUND FRIDAY
AND INTO NEXT WEEKEND BUT REMAIN NEAR SEASONAL LEVELS WITH NO
EXTREME HEAT IN SIGHT FOR AT LEAST THE NEXT SEVEN DAYS.
AVIATION
UPDATED AT 1045Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
THE PRIMARY AVIATION CONCERNS DURING THE TAF PERIOD WILL ONCE
AGAIN BE THE POTENTIAL FOR GUSTY OUTFLOW WINDS, BLOWING DUST, AND
TS CONDITIONS/IMPACTS AT THE TERMINALS. WINDS ARE LIKELY TO FOLLOW
TYPICAL DIURNAL TRENDS THROUGH EARLY THIS EVENING, WITH SPEEDS
GENERALLY AOB 10 KTS AND WESTERLY GUSTS INTO THE TEENS DEVELOPING
DURING THE AFTERNOON. CONFIDENCE IN THE WIND FORECAST DECREASES
CONSIDERABLY THIS EVENING WITH MANY DISCREPANCIES IN THE HI- RES
GUIDANCE. HOWEVER, AFTERNOON DISTANT TS OVER THE HIGH TERRAIN TO
THE NORTH AND EAST AND OVER PORTIONS OF SOUTHEAST AZ WILL BE
CAPABLE OF FORMING LONG-LIVED OUTFLOWS WHICH WILL PUSH TOWARDS THE
TERMINALS BY THE EVENING. THESE OUTFLOWS WOULD BE CAPABLE OF
ABRUPT WINDS SHIFTS, COULD CARRY SOME BLOWING DUST (ESPECIALLY IF
ARRIVE FROM THE SOUTH), AND THEN MAY BE FOLLOWED BY TS DEVELOPMENT
IN THE PHOENIX AREA BY MID-LATE EVENING OR INTO THE OVERNIGHT
HOURS. AMENDMENTS WILL LIKELY BE NEEDED TO THE CURRENT TAF AS
CONDITIONS EVOLVE.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR AVIATION WEATHER CONCERNS ARE EXPECTED THROUGH THE NEXT
24 HOURS UNDER PERIODS OF FEW-SCT MID TO HIGH CLOUD DECKS AND
OTHERWISE MOSTLY CLEAR SKIES. AT KIPL, WINDS WILL PRIMARILY STAY
SOUTHEASTERLY. THERE IS A LOW CHANCE (10%) FOR AN ISOLATED STRONG
TS WITHIN THE VICINITY OF KIPL THIS AFTERNOON, WHICH COULD CAUSE
AN ABRUPT WIND SHIFT (LIKELY OUT OF THE SOUTHWEST) AND STRONG
GUSTS. AT KBLH, WINDS WILL GENERALLY FLUCTUATE BETWEEN SSE AND
SSW. OVERALL, WIND SPEEDS SHOULD GENERALLY REMAIN AOB 12 KTS.
FIRE WEATHER
GRADUAL COOLING TEMPERATURES TO NEAR TO SLIGHTLY BELOW NORMAL
LEVELS CAN BE EXPECTED THROUGHOUT THE WEEK. ELEVATED MOISTURE
WILL MAINTAIN AFTERNOON MINRHS ABOVE 20% EACH AFTERNOON ALONG WITH
GOOD TO EXCELLENT OVERNIGHT RECOVERIES. THE CHANCES FOR SHOWER AND
THUNDERSTORM ACTIVITY AS WELL AS WETTING RAINFALL WILL REMAIN
ELEVATED THROUGH THE MIDDLE OF THE WEEK, ESPECIALLY ACROSS THE
EASTERN DISTRICTS. THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL
DECREASE NOTICEABLY BY THE END OF THE WEEK THROUGH NEXT WEEKEND
AS DRIER AIR FILTERS IN. OUTSIDE OF GUSTY AND ERRATIC WINDS DUE TO
THUNDERSTORMS, WINDS WILL FOLLOW THE FAMILIAR DIURNAL TRENDS,
WITH TYPICAL AFTERNOON UPSLOPE BREEZINESS AROUND 20 MPH.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...EXTREME HEAT WARNING UNTIL 8 PM MST THIS EVENING FOR AZZ530-532.
CA...EXTREME HEAT WARNING UNTIL 8 PM PDT THIS EVENING FOR CAZ563-566-
567-569-570.
SHORT TERM...LOJERO
LONG TERM...LOJERO
AVIATION...WHITTOCK
FIRE WEATHER...LOJERO
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page