688
FXUS65 KPSR 310532
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1032 PM MST WED JUL 30 2025
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- ABOVE NORMAL TEMPERATURES WITH LOWER DESERT HIGHS BETWEEN
108-114 DEGREES WILL PREVAIL THROUGH NEXT WEEK, RESULTING IN
WIDESPREAD MODERATE HEATRISK WITH AREAS OF MAJOR HEATRISK ACROSS
THE SOUTH-CENTRAL AZ LOWER DESERTS FOR FRIDAY AND SATURDAY WITH
EXTREME HEAT WARNINGS IN EFFECT.
- LIMITED MONSOON MOISTURE WILL RESULT IN DAILY CHANCES FOR
THUNDERSTORM ACTIVITY ACROSS THE EASTERN ARIZONA HIGH TERRAIN
THROUGH FRIDAY, WITH ONLY A VERY SLIGHT CHANCE FOR ISOLATED
ACTIVITY ACROSS THE SOUTH-CENTRAL AZ LOWER DESERTS LATE THURSDAY
AFTERNOON AND EVENING.
SHORT TERM /TODAY THROUGH THURSDAY/
LATEST WATER VAPOR SATELLITE IMAGERY SHOWS A SUBSTANTIAL AMOUNT
MID TO UPPER-LEVEL DRY AIR IN PLACE AS A RESULT OF SOUTHWESTERLY
FLOW ALOFT ENVELOPED ACROSS MUCH OF SOUTHERN CA THROUGH WESTERN
AND CENTRAL AZ FROM A TROUGH SITUATED ACROSS CENTRAL CA. AS A
RESULT OF THIS PATTERN, MOISTURE LEVELS CONTINUE TO BE WELL-BELOW
NORMAL WITH THE LATEST SPC MESOANALYSIS SHOWING PWATS RANGING
BETWEEN 0.5-0.9" ACROSS THE LOWER DESERTS OF SOUTH-CENTRAL AND
SOUTHWESTERN AZ THROUGH SOUTHEAST CA TO AS HIGH AS 1.0-1.3"
ACROSS THE SOUTHEASTERN THIRD OF AZ. GIVEN THE MEAGER MOISTURE IN
PLACE, THUNDERSTORM ACTIVITY SIMILAR TO THE PAST COUPLE OF DAYS
WILL BE LIMITED TO THE EASTERN AND SOUTHEASTERN THIRD OF AZ THIS
AFTERNOON THROUGH EARLY THIS EVENING WHILE THE REST OF THE REGION
WILL REMAIN DRY WITH MOSTLY CLEAR SKIES. HEADING INTO THURSDAY,
MOISTURE LEVELS DO IMPROVE SOME AS PWATS INCREASE TO 1.0-1.3"
ACROSS THE SOUTH-CENTRAL AZ LOWER DESERTS, WHICH COULD ALLOW FOR
SOME OF THUNDERSTORM ACTIVITY THAT DOES DEVELOP DURING THE
AFTERNOON ACROSS THE EASTERN THIRD OF AZ TO SPREAD WESTWARD.
HOWEVER, IT IS STILL LOOKING LIKE ANY ACTIVITY THAT ATTEMPTS TO
DEVELOP INTO THE LOWER-DESERTS WILL BE ISOLATED AT BEST WITH POPS
AT AROUND 10%.
THE MAIN STORY WILL CONTINUE TO BE THE HOT TEMPERATURES AS
TEMPERATURES WILL BE A GOOD 3-5 DEGREES ABOVE NORMAL, RANGING
BETWEEN 107-111 DEGREES ACROSS THE LOWER DESERTS THROUGH THURSDAY
AS 500 MB HEIGHT FIELDS WILL RANGE BETWEEN 593-596DM. THIS WILL
RESULT IN WIDESPREAD MODERATE HEATRISK AND THUS ANYONE SCHEDULING
OUTDOOR ACTIVITIES AS WELL AS THE MOST VULNERABLE COMMUNITIES
WILL NEED TO TAKE THE NECESSARY HEAT PRECAUTIONS.
LONG TERM /FRIDAY THROUGH TUESDAY/
THE UPPER-LEVEL RIDGE WILL STRENGTHEN ACROSS CENTRAL AND SOUTHERN
AZ FRIDAY AND SATURDAY AS 500 MB HEIGHT FIELDS INCREASE UP TO
597-598DM. THIS WILL TRANSLATE TO HOTTER TEMPERATURES AS HIGHS
WILL RANGE BETWEEN 110-114 DEGREES ACROSS THE LOWER DESERTS WITH
EARLY MORNING LOWS BETWEEN 85-90 DEGREES ACROSS THE PHOENIX METRO
AREA. THIS WILL BE ENOUGH TO RESULT IN AREAS OF MAJOR HEATRISK
MATERIALIZING ACROSS THE SOUTH-CENTRAL AZ LOWER DESERTS AND AS A
RESULT, EXTREME HEAT WARNINGS HAVE BEEN ISSUED FOR BOTH FRIDAY
AND SATURDAY.
WE ARE EXPECTING SOME LINGERING MOISTURE ACROSS THE EASTERN 1/3RD
OF ARIZONA ON FRIDAY, BUT WITH THE HIGH CENTER SETTING UP
DIRECTLY OVER SOUTHERN ARIZONA ANY CHANCES FOR SHOWERS OR STORMS
SHOULD BE LIMITED TO HIGHER TERRAIN AREAS. MORE ORGANIZED WESTERLY
DRY FLOW WILL ALSO SET UP FRIDAY INTO SATURDAY WITH PWATS QUICKLY
DROPPING TO AROUND 0.75" ON SATURDAY, MOSTLY ENDING ANY RAIN
CHANCES EVEN OVER THE HIGHER TERRAIN. THIS DRY WESTERLY FLOW IS
EXPECTED TO AT LEAST PERSIST THROUGH SUNDAY, BUT BY MONDAY MODELS
BEGIN TO SHIFT THE HIGH CENTER MORE OVER NEW MEXICO. IF THIS SHIFT
OCCURS, IT MAY ALLOW FOR SOME MOISTURE TO BEGIN SEEPING BACK
NORTHWARD INTO SOUTHERN ARIZONA AS EARLY AS MONDAY. LIMITED 10%
POPS HAVE ADDED ACROSS THE PHOENIX METRO FOR MONDAY AND TUESDAY
WITH CHANCES CLOSER TO 20% OVER THE EASTERN ARIZONA HIGH TERRAIN.
TEMPERATURES ARE LIKELY TO TAKE A SLIGHT DIP OF A COUPLE OF
DEGREES SUNDAY INTO MONDAY AS THE RIDGE SHIFTS AWAY FROM THE AREA
AND WEAKENS SLIGHTLY. HOWEVER, WE ARE STILL ANTICIPATING THE
ABOVE NORMAL TEMPERATURES TO CONTINUE WITH HIGHS BETWEEN 107-111
DEGREES ACROSS THE LOWER DESERTS. LOOKING OUT TOWARD THE LATTER
HALF OF NEXT WEEK, GUIDANCE IS STILL POINTING AT A RESTRENGTHENING
OF THE RIDGE AND THE POTENTIAL RETURN OF EXTREME HEAT.
AVIATION
UPDATED AT 0530Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
THE PRIMARY WEATHER CONCERN WILL BE LOW CONFIDENCE ON THE WIND
FORECAST FOR THURSDAY EVENING DUE TO UNCERTAINTY IN EXACT LOCATION
AND STRENGTH OF THUNDERSTORMS THAT MAY DEVELOP TO THE
SOUTH/SOUTHEAST OF THE TERMINALS. A DECAYING OUTFLOW WILL SHIFT
WINDS OUT OF THE SOUTHEAST WITHIN THE NEXT HOUR OR SO. THOUGH THE
SHIFT WILL BE MORE ABRUPT THAN USUAL, SPEEDS ARE LIKELY TO BE AOB
12 KTS AND CONFIDENCE IS LOW THAT IT WILL REACH KSDL/KDVT.
THURSDAY, WINDS WILL SLOWLY VEER FROM SE TO SW DURING THE LATE
MORNING INTO THE AFTERNOON. EXPECT OCCASIONAL WESTERLY GUSTS INTO
THE UPPER TEENS ACROSS THE TERMINAL DURING THE MID-LATE AFTERNOON.
THUNDERSTORMS ARE ANTICIPATED TO FORM SOUTH AND EAST OF THE
TERMINALS THURSDAY AFTERNOON, CLOSER THAN PREVIOUS DAYS THIS WEEK.
THE PROXIMITY OF STORMS WILL MEAN THAT GUSTY OUTFLOW WINDS HAVE A
BETTER CHANCE OF REACHING THE TERMINALS, THOUGH THE EXACT
DIRECTION AND TIMING ARE QUITE UNCERTAIN AND HIGHLY DEPENDENT ON
WHERE STORM DEVELOPMENT IS MOST FOCUSED FORM AND THEIR STRENGTH.
AT THIS TIME, CONFIDENCE IS TOO LOW TO INCLUDE THE IMPACTS OF ANY
OUTFLOWS IN THE TAF.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
WINDS WILL FOLLOW A PATTERN NEARLY IDENTICAL TO THAT OF THE LAST
24 HOURS UNDER CLEAR SKIES. WINDS WILL BECOME VERY LIGHT AND VRB
OVERNIGHT AT KBLH, THEN SOUTH WINDS WILL PICK UP ONCE AGAIN AROUND
MIDDAY THURSDAY, DEVELOPING GUSTS INTO THE LOW 20S DURING THE
AFTERNOON. AT KIPL, WEST WINDS WILL LINGER THROUGH 10-12Z, THEN
BEGIN TO FAVOR SOUTHEAST THROUGH THURSDAY AFTERNOON. ANOTHER
PERIOD OF STRONGER WEST WINDS IS ANTICIPATED AT KIPL THURSDAY
EVENING.
FIRE WEATHER
LIMITED MONSOON MOISTURE WILL PROVIDE FOR DAILY CHANCES FOR
SHOWERS AND ISOLATED THUNDERSTORMS PRIMARILY OVER THE EASTERN
ARIZONA HIGH TERRAIN. CHANCES FOR WETTING RAINS WILL REMAIN BELOW
10% RESULTING IN AT LEAST MINOR RISK OF DRY LIGHTNING. AFTERNOON
MINRHS THROUGH FRIDAY WILL REMAIN BETWEEN 10-15% ACROSS THE LOWER
DESERTS TO 15-20% IN HIGHER TERRAIN AREAS. OUTSIDE OF THE
INFLUENCE OF THUNDERSTORMS, WINDS WILL GENERALLY FOLLOW DIURNAL
TENDENCIES WITH TYPICAL AFTERNOON UPSLOPE GUSTINESS. TEMPERATURES
WILL REMAIN ABOVE NORMAL WITH LOWER DESERT HIGHS MOSTLY BETWEEN
108-112 DEGREES. HIGH PRESSURE WILL AGAIN TAKE OVER ACROSS THE
REGION BY THE WEEKEND WITH CONDITIONS DRYING OUT FURTHER. THIS
WILL PUSH HUMIDITIES INTO THE SINGLE DIGITS AND END ANY RAIN
CHANCES.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...EXTREME HEAT WARNING FROM 10 AM FRIDAY TO 8 PM MST SATURDAY FOR
AZZ534-537>544-546-548>555-559.
CA...NONE.
SHORT TERM...LOJERO
LONG TERM...LOJERO/KUHLMAN
AVIATION...WHITTOCK
FIRE WEATHER...KUHLMAN
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