443
FXUS65 KPSR 101720
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1020 AM MST FRI JUL 10 2026
UPDATE
UPDATED AVIATION
KEY MESSAGES
- SEASONABLY HOT TEMPERATURES CAN BE EXPECTED INTO NEXT WEEK, WITH
THE HOTTEST TEMPERATURES EXPECTED TODAY WITH LINGERING EXTREME HEAT
WARNINGS ACROSS SOME LOWER DESERT AREAS.
- THE CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE MAINLY CONFINED
ACROSS THE HIGHER TERRAIN AREAS OF EASTERN ARIZONA AS WELL AS ACROSS
SOUTHEAST ARIZONA THROUGH SATURDAY.
- DEEPER MOISTURE MOVING INTO THE REGION THROUGH EARLY NEXT WEEK
WILL RESULT IN BETTER CHANCES FOR MORE WIDESPREAD SHOWERS AND
THUNDERSTORMS.
SHORT TERM /TODAY THROUGH SATURDAY/
LATEST OBJECTIVE ANALYSIS DEPICTS THE SUBTROPICAL RIDGE OF HIGH
PRESSURE CENTERED NEAR THE SOUTHERN CALIFORNIA COAST WHILE THE
EASTERN EDGE EXTENDS INTO ARIZONA WITH NORTHERLY MID-LEVEL FLOW
ENCOMPASSING THE STATE. THE HIGH WILL GRADUALLY MOVE EAST
NORTHEASTWARD THROUGHOUT THE DAY THROUGH SOUTHERN CA AND THE
SOUTHERN GREAT BASIN WITH 500 MB HEIGHT FIELDS EXPECTED TO HOVER
BETWEEN 593-594DM, WHICH IS SLIGHTLY LOWER THAN THE LAST COUPLE OF
DAYS. AS A RESULT OF THIS SLIGHT LOWERING OF THE UPPER-LEVEL HEIGHT
FIELDS, AFTERNOON HIGH TEMPERATURES TODAY WILL BE A COUPLE OF
DEGREES COOLER WITH READINGS TOPPING OUT BETWEEN 109-112 DEGREES
ACROSS THE SOUTH-CENTRAL AZ LOWER DESERTS TO BETWEEN 108-115 DEGREES
ACROSS THE WESTERN DESERTS. EXTREME HEAT WARNINGS WILL REMAIN IN
PLACE THROUGH THIS EVENING ACROSS THE WESTERN HALF OF IMPERIAL
COUNTY AS WELL AS ALONG THE LOWER COLORADO RIVER VALLEY AS THESE
AREAS WILL EXPERIENCE THE HOTTEST TEMPERATURES WITH READINGS TOPPING
OUT CLOSE TO 115 DEGREES, RESULTING IN AREAS OF MAJOR HEATRISK. AN
EXTREME HEAT WARNING IS ALSO IN EFFECT THROUGH THIS EVENING FOR THE
PHOENIX METRO AREA, MOSTLY DUE TO VERY WARM EARLY MORNING LOWS
EXPECTED TO BE NEAR 90 DEGREES MAKING IT DIFFICULT FOR THE BODY TO
RECOVER FROM THE DAYTIME HEAT. TEMPERATURES WILL SLIGHTLY COOL EVEN
FURTHER ON SATURDAY WITH AFTERNOON HIGHS ACROSS THE LOWER DESERTS
GENERALLY BETWEEN 106-110 DEGREES.
SIMILAR TO YESTERDAY, A GOOD DEAL OF SUBSIDENCE AND SLIGHTLY DRIER
AIR FROM THE NORTHERLY FLOW WILL RESULT IN LIMITED STORM COVERAGE
WITH ACTIVITY THIS AFTERNOON INTO EARLY THIS EVENING RELEGATED TO
THE WHITE MOUNTAINS AND FAR SOUTHEAST AZ AS INDICATED BY THE LATEST
HI-RES GUIDANCE. HEADING INTO SATURDAY, THE OVERALL PATTERN WILL BE
CHANGING SIGNIFICANTLY AS THE SUBTROPICAL HIGH QUICKLY MIGRATES
NORTHEASTWARD TOWARDS UTAH AND THE CENTRAL ROCKIES. THIS WILL CAUSE
THE MID-LEVEL FLOW TO SHIFT MORE OUT OF THE EAST, HELPING TO IMPORT
HIGHER MOISTURE INTO THE REGION. IN ADDITION, A STRONG CONVECTIVE
COMPLEX OVER NORTHERN SONORA FRIDAY EVENING WILL HELP BOOST MOISTURE
LEVELS AS WELL. LATEST HI-RES MODEL GUIDANCE SHOWS ACTIVITY
DEVELOPING OVER THE EASTERN AZ HIGHER TERRAIN BEFORE MOVING
WESTWARD, WITH WIDESPREAD CONVECTIVE ACTIVITY LIKELY ACROSS MUCH OF
SOUTHEAST AZ. ACROSS THE SOUTH- CENTRAL AZ LOWER DESERTS, CONVECTIVE
ACTIVITY IS LIKELY TO BE MUCH MORE LIMITED AS THE LATEST FORECAST
SOUNDINGS INDICATE A GOOD DEAL OF CONVECTIVE INHIBITION IN PLACE.
HOWEVER, THERE ARE STRONG INDICATIONS FROM THE LATEST HI-RES
GUIDANCE THAT A STRONG OUTFLOW OR POTENTIALLY MULTIPLE OUTFLOWS
EMANATING FROM THUNDERSTORM ACTIVITY ACROSS SOUTHEAST AZ WILL
MIGRATE NORTHWESTWARD INTO SOUTH-CENTRAL AZ, PRODUCING GUSTY WINDS
AS WELL AS AREAS OF BLOWING DUST. IF STRONG/MULTIPLE OUTFLOW
COLLISIONS OCCUR, THEN IT COULD BE ENOUGH TO GENERATE ADDITIONAL
STORMS. OTHERWISE, THE OUTFLOW WILL LIKELY SERVE TO INCREASE THE LOW-
LEVEL MOISTURE EVEN MORE ACROSS THE REGION, SETTING THE STAGE FOR A
BETTER THERMODYNAMIC ENVIRONMENT HEADING INTO SUNDAY.
LONG TERM /SUNDAY THROUGH THURSDAY/
EXCELLENT AGREEMENT REMAINS IN PLACE AMONGST THE GUIDANCE OF THE
UPPER HIGH QUICKLY MIGRATING NORTHEASTWARD INTO THE PLAINS AND UPPER
MIDWEST REGIONS THROUGH NEXT WEEK. THIS OVERALL PATTERN SETUP WILL
MAINTAIN EASTERLY FLOW IN PLACE ACROSS THE REGION, HELPING TO
TRANSPORT MOISTURE AND TRANSITION THE DESERT SOUTHWEST INTO A MORE
ACTIVE MONSOONAL PATTERN. THE LATEST EPS AND GEFS INDICATE PWATS
CLIMBING AND REMAINING ABOVE 1.5" THROUGH MOST OF NEXT WEEK ALONG
WITH LOW-LEVEL MIXING RATIOS REMAINING ABOVE 10 G/KG.
AS MENTIONED PREVIOUSLY, SUNDAY WILL OFFER THE FIRST REAL SHOT THIS
MONSOON SEASON FOR MORE WIDESPREAD CONVECTIVE ACTIVITY TO AFFECT THE
SOUTH-CENTRAL AZ LOWER DESERTS, GIVEN THE MORE FAVORABLE
THERMODYNAMIC ENVIRONMENT THAT WILL BE IN PLACE AND THIS IS
REFLECTED IN THE LATEST NBM WITH POPS SOLIDLY IN THE 40-60% RANGE BY
THE EARLY EVENING HOURS. THE CHANCES FOR ADDITIONAL CONVECTIVE
ACTIVITY WILL CONTINUE EACH DAY THROUGH NEXT WEEK AND WILL EXPAND
FURTHER WESTWARD TO INCLUDE THE WESTERN DESERTS WITH DAILY
VARIATIONS IN THE OVERALL COVERAGE. THERE ARE INDICATIONS FROM
GUIDANCE THAT A RATHER ORGANIZED EASTERLY WAVE/INVERTED TROUGH MAY
MOVE IN FROM THE EAST AND AFFECT THE REGION SOMETIME TOWARDS THE
LATTER HALF OF THE WEEK. HOWEVER, GIVEN THAT THE SYNOPTIC MODELS ARE
NOTORIOUSLY POOR IN THE OVERALL HANDLING OF THESE EASTERLY
WAVES/INVERTED TROUGHS, HIGH UNCERTAINTY EXISTS IN THE OVERALL
FORECAST. IF THE EASTERLY WAVE/INVERTED TROUGH SCENARIO PANS OUT,
THEN THERE IS A GOOD CHANCE FOR ENHANCED CONVECTIVE ACTIVITY TO
MATERIALIZE ACROSS MUCH OF THE REGION. THIS IS SOMETHING THAT WILL
HAVE TO BE MONITORED DURING THE NEXT SEVERAL DAYS AS IT COULD BE
HIGHLY IMPACTFUL.
WITH THE ELEVATED MOISTURE LEVELS AND MORE CLOUD COVER THAT WILL BE
IN PLACE, TEMPERATURES THROUGH THE MUCH OF NEXT WEEK WILL REMAIN
NEAR TO SLIGHTLY ABOVE NORMAL WITH READINGS ACROSS MUCH OF THE LOWER
DESERTS IN THE UPPER 100S TO AROUND 110 DEGREES FOR AFTERNOON HIGHS
AND OVERNIGHT LOWS IN THE 80S. THIS WILL MAINTAIN THE OVERALL
HEATRISK LEVELS SOLIDLY IN THE MODERATE CATEGORY.
AVIATION
UPDATED AT 1720Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
LOFTED DUST/HAZE IMPACTING SLANTWISE VISIBILITY AND UNCERTAINTY IN
WIND SHIFTS AND GUSTS ARE THE MAIN WEATHER ISSUES UNDER A GRADUAL
INCREASE IN MID/HIGH CLOUD DECKS. CONFIDENCE IS GOOD THAT WINDS WILL
TRANSITION TO W/SW BY EARLY AFTERNOON. GUSTS 15-20KT MAY AFFECT SOME
TERMINALS LATE AFTERNOON THROUGH EARLY EVENING, HOWEVER CONFIDENCE IS
MUCH LOWER AS COMPARED TO PREVIOUS DAYS. GUSTS MAY BE MORE EVIDENT
AND PERSIST THROUGH THE EVENING INTO THE OVERNIGHT WITH A LOW CHANCE
OF ADDITIONAL LOFTED DUST. VERY LOW CONFIDENCE EXISTS REGARDING A
WIND SHIFT BACK TO E/SE OVERNIGHT AND TIMING. DISTANT OUTFLOWS MAY
FORCE A WIND SHIFT AROUND 09Z (SIMILAR TO THIS MORNING), OR A LACK
OF OUTFLOW MAY CREATE JUST A FEW HOURS OF VARIABLE WINDS AROUND
SUNRISE BEFORE REVERTING BACK TO W/SW.
SATURDAY OUTLOOK: CONFIDENCE IS INCREASING THAT STORMS IN EASTERN
AND SOUTHERN ARIZONA WILL SEND MULTIPLE STRONG OUTFLOW BOUNDARIES
TOWARDS PHOENIX SATURDAY EVENING. WHILE THUNDERSTORMS ARE NOT
ANTICIPATED TO DIRECTLY AFFECT THE TERMINALS, ABRUPT WIND SHIFTS
WITH BLOWING DUST APPEAR LIKELY MID/LATE EVENING WHICH MAY INCUR A
PERIOD OF MVFR OR IFR VISIBILITIES.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR WEATHER ISSUES WILL EXIST THROUGH SATURDAY AFTERNOON WITH
SOME HIGH CLOUD DECKS MOVING INTO THE REGION. WINDS SHOULD GENERALLY
REMAIN S AT KBLH WITH OCCASIONAL GUSTINESS, WHILE DIRECTION RANGE
FROM E TO S AT KIPL THROUGH THE PERIOD. THERE IS SOME UNCERTAINTY IN
WINDS SATURDAY MORNING WHERE SOME VARIABILITY MAY OCCUR.
FIRE WEATHER
SEASONABLY HOT TEMPERATURES WILL PREVAIL THROUGH THE NEXT SEVERAL
DAYS AS READINGS WILL BE NEAR TO SLIGHTLY ABOVE NORMAL. DRY
CONDITIONS WILL PREVAIL TODAY BEFORE THUNDERSTORM CHANCES INCREASE
SATURDAY ACROSS THE HIGHER TERRAIN AREAS OF SOUTH-CENTRAL AZ. MORE
WIDESPREAD MONSOONAL ACTIVITY IS LIKELY STARTING SUNDAY AND
CONTINUING THROUGH NEXT WEEK. AFTERNOON HUMIDITY LEVELS TODAY WILL
RANGE BETWEEN 10-20% ACROSS THE WESTERN DISTRICTS AND 15-25% ACROSS
THE EASTERN DISTRICTS. AFTERNOON HUMIDITY LEVELS SATURDAY INCREASE
TO 15-25% AREAWIDE. STARTING ON SUNDAY AND PERSISTING THROUGH MUCH
OF NEXT WEEK, AFTERNOON HUMIDITY LEVELS WILL INCREASE EVEN FURTHER
AND BOTTOM OUT ABOVE 20% AS MOISTURE LEVELS INCREASE, AND THUS
ALLEVIATING MUCH OF THE FIRE WEATHER CONCERNS. OUTSIDE OF ANY
POTENTIAL OUTFLOWS/THUNDERSTORM WINDS, WINDS SHOULD FAVOR DIURNAL
TRENDS WITH THE TYPICAL AFTERNOON BREEZINESS AROUND 20 MPH. SOME
STRONGER AFTERNOON GUSTS BETWEEN 20-30 MPH WILL BE COMMON ALONG THE
LOWER COLORADO RIVER VALLEY TODAY.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...EXTREME HEAT WARNING UNTIL 8 PM MST THIS EVENING FOR AZZ530-537-
540-542>544-546-548-550-551.
CA...EXTREME HEAT WARNING UNTIL 8 PM PDT THIS EVENING FOR CAZ562-566-
567-569-570.
SHORT TERM...LOJERO
LONG TERM...LOJERO
AVIATION...18
FIRE WEATHER...LOJERO
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