050
FXUS65 KPSR 012320
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
420 PM MST SAT AUG 1 2026
UPDATE...UPDATED 00Z AVIATION DISCUSSION
KEY MESSAGES
- EXTREME HEAT WILL PERSIST THROUGH THE START OF NEXT WEEK WITH
HIGH TEMPERATURES TOPPING OUT IN THE 110 TO 118 DEGREE RANGE
OVER MUCH OF THE LOWER DESERTS, HOVERING RIGHT AROUND RECORD
LEVELS.
- EXTREME HEAT WARNINGS ARE IN EFFECT REGIONWIDE THROUGH MONDAY.
- HIGH PRESSURE AND DRIER AIR OVER THE REGION WILL CONFINE
SHOWERS AND THUNDERSTORMS PRIMARILY TO FAR EASTERN AND
SOUTHEASTERN ARIZONA AREAS THROUGH AT LEAST MONDAY.
- SHOWER AND THUNDERSTORM CHANCES INCREASE ACROSS SOUTH-CENTRAL
ARIZONA BY THE SECOND HALF OF NEXT WEEK.
SHORT TERM /TODAY THROUGH MONDAY/
A VERY HOT WEEKEND IS UNDERWAY AS AN ANOMALOUSLY STRONG RIDGE OF
HIGH PRESSURE SITS OVER THE REGION. THIS MORNING'S 12Z PHX SOUNDING
SAMPLED A 500 MB HEIGHT OF 601 DM WITH MESOANALYSIS SHOWING THE
RIDGE CENTERED OVER SOUTH-CENTRAL ARIZONA. THE RIDGE WILL BE AT
PEAK INTENSITY TODAY, YIELDING WELL ABOVE NORMAL AND POTENTIALLY
RECORD-BREAKING TEMPERATURES, BEFORE BEGINNING TO WEAKEN AS A
TROUGH PASSES THROUGH BC/ALBERTA. AS THE RIDGE WEAKENS, 500 MB
HEIGHTS WILL DROP FROM 598-600 DM TODAY TO AROUND 595-597 DM
TOMORROW. REGARDLESS OF THE RIDGE WEAKENING TOMORROW, TEMPERATURES
WILL REMAIN WELL ABOVE NORMAL WITH FORECAST HIGHS RANGING FROM
112-118 DEGREES ACROSS THE LOWER DESERTS SUNDAY AFTERNOON.
AFTERNOON TEMPERATURES MONDAY WILL SEE ~2-4 DEGREE DROP FROM
SUNDAY AS THE WEAKENING TREND OF THE RIDGE CONTINUES INTO THE
START OF THE NEW WORKWEEK. WHILE DAYTIME HIGHS REMAIN WELL ABOVE
NORMAL INTO EARLY NEXT WEEK, MORNING LOWS WILL ALSO OFFER LITTLE
RELIEF FROM THE HEAT AS TEMPERATURES ONLY COOL INTO THE UPPER 80S
TO LOW 90S EACH MORNING. THE COMBINATION OF THESE VERY HOT DAYTIME
TEMPERATURES AND WARM MORNING LOWS WILL LEAD TO WIDESPREAD MAJOR
HEATRISK ALONG WITH EXTREME HEATRISK ACROSS THE PHOENIX METRO
THROUGH SUNDAY. THUS, EXTREME HEAT WARNINGS REMAIN IN EFFECT
THROUGH THE START OF THE NEW WORKWEEK.
WITH THE STRONG RIDGE PROMOTING SUBSIDENCE OVER THE REGION ALONG
WITH FORECAST SOUNDINGS SHOWING LIMITED MOISTURE PRIMARILY
FOCUSED AROUND 500 MB, MONSOONAL ACTIVITY WILL REMAIN QUITE
LIMITED FOR OUR AREA THIS WEEKEND WITH THUNDERSTORMS FAVORING THE
WHITE MOUNTAINS. GIVEN THE DRY SUB-CLOUD LAYER AND HIGH DCAPE
VALUES, THESE THUNDERSTORMS COULD GENERATE STRONG OUTFLOWS THAT
COULD AID IN DEVELOPING A FEW ISOLATED SHOWER/STORMS THIS WEEKEND
INTO SOUTHERN GILA COUNTY. THIS MAY BECOME MORE LIKELY TOMORROW AS
HREF GUIDANCE SUPPORT INCREASING THUNDERSTORM ACTIVITY ACROSS FAR
EASTERN AZ TOMORROW AFTERNOON. BETTER MOISTURE WILL BEGIN TO
CREEP BACK INTO THE AREA MONDAY AND WILL ALLOW FOR INCREASING
THUNDERSTORM ACTIVITY PRIMARILY ACROSS SOUTHEAST ARIZONA MONDAY
AFTERNOON. NORTHEAST STEERING FLOW WILL KEEP THIS ACTIVITY AWAY
FROM OUR AREA, WHILE A FEW STORMS MAY DEVELOP/MOVE INTO SOUTHERN
GILA COUNTY.
LONG TERM /TUESDAY THROUGH FRIDAY/
THE MONSOON HIGH IS FORECAST TO WEAKEN SUNDAY INTO MONDAY WITH H5
HEIGHTS DROPPING TO 594-596DAM, OR RIGHT AROUND THE 90TH
PERCENTILE OF CLIMATOLOGY, BY THE END OF THE DAY MONDAY. THE HIGH
WILL ALSO BECOME FLATTER AND MORE STRETCHED OUT ACROSS THE
SOUTHERN TIER OF THE CONUS AND LIKELY PERSIST THROUGH THE END OF
THE WEEK. DESPITE THE HIGH WEAKENING, THE RESIDUAL HEAT DOME WILL
TAKE SOME TIME TO COOL. HIGH TEMPERATURES ARE FORECAST TO COOL 1-3
DEGREES INTO TUESDAY, FROM MONDAY'S READINGS, AND ANOTHER 1-3
DEGREES INTO WEDNESDAY. LOWS WILL REMAIN QUITE WARM EACH DAY,
MAINLY IN THE MID 80S TO AROUND 90F ACROSS THE LOWER DESERTS. THE
EXTREME HEAT FOOTPRINT WILL DECREASE AS THE TEMPERATURES DECLINE,
BUT A CONTINUATION OF THE EXTREME HEAT WARNING THROUGH TUESDAY MAY
BE NEEDED FOR AT LEAST THE PHOENIX AREA WITH LINGERING WIDESPREAD
MAJOR HEATRISK ACROSS THE METRO AREA BASED ON THE CURRENT
FORECAST. MOST OTHER AREAS WILL FALL TO THE MODERATE RISK LEVEL
BY TUESDAY. TEMPERATURES ARE THEN FORECAST TO REMAIN FAIRLY
SIMILAR DAY-TO-DAY WEDNESDAY THROUGH THE END OF THE WEEK, WITH
MINIMAL SYNOPTIC CHANGES, BARRING ANY STORM INFLUENCES.
WITH THE WEAKER AND FLATTER HIGH, AND BEING ON THE SOUTHERN HALF
OF THE HIGH, THERE WILL BE A LONGER FETCH OF EASTERLY WINDS ACROSS
SOUTHERN NEW MEXICO, SOUTHERN ARIZONA, AND NORTHERN MEXICO BY
TUESDAY. THIS PATTERN SHIFT WILL ALLOW MOISTURE TO BEGIN TO
INCREASE AGAIN ACROSS SOUTHERN AND EASTERN ARIZONA MONDAY THROUGH
THE MIDDLE OF THE WEEK. AS A RESULT, CONVECTIVE POTENTIAL WILL
TICK UPWARDS EARLY NEXT WEEK, AND THE EASTERLY STEERING FLOW
ACROSS SOUTHERN ARIZONA WILL BE A BETTER TRAJECTORY ACROSS THE
AREA TO HELP SPREAD CONVECTION MORE INTO THE LOWER DESERTS BY THE
SECOND HALF OF NEXT WEEK. LATEST NBM/WPC FORECAST SHOW 10-30% POPS
ACROSS SOUTH-CENTRAL ARIZONA BY WEDNESDAY AND CONTINUING THROUGH
THE END OF THE WEEK. DESPITE LOWER POPS ON TUESDAY, STRONG OUTFLOW
WINDS MAY AT LEAST PROGRESS THROUGH SOUTH-CENTRAL ARIZONA. THE
SYNOPTIC PATTERN NEXT WEEK WILL OPEN THE DOOR FOR SOME EASTERLY
WAVES/INVERTED TROUGHS TO PROGRESS ACROSS THE AREA AND ENHANCE
CONVECTIVE POTENTIAL, BUT IT IS STILL TOO EARLY FOR MODELS TO
FULLY RESOLVE ANY OF THESE FEATURES TO HELP DETERMINE WHAT DAY, IF
ANY, WILL HAVE BETTER ODDS FOR STORMS ACROSS THE LOWER DESERTS.
AVIATION
UPDATED AT 2315Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO AVIATION WEATHER CONCERNS UNDER FEW-SCT MID TO HIGH-LEVEL
CLOUDS CAN BE EXPECTED THROUGHOUT THE TAF PERIOD. THE OVERALL WIND
PATTERN WILL GENERALLY EXHIBIT THE TYPICAL DIURNAL TENDENCIES WITH
OCCASIONAL AFTERNOON/EARLY EVENING GUSTINESS NEAR 20 KTS.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO AVIATION WEATHER CONCERNS UNDER MOSTLY CLEAR SKIES CAN BE
EXPECTED THROUGHOUT THE TAF PERIOD. AT KIPL, SOUTHEAST WINDS WILL
TEMPORARY SHIFT OUT OF THE WEST THIS EVENING BEFORE SHIFTING BACK
OUT OF THE SOUTHEAST OVERNIGHT. AT KBLH, WINDS WILL GENERALLY
FLUCTUATE BETWEEN THE SOUTH-SOUTHEAST TO SOUTHWEST. OVERALL SPEEDS
WILL REMAIN UNDER 12 KTS, ALTHOUGH SOME OCCASIONAL GUSTS OF AROUND
20 KTS CAN BE EXPECTED AT KBLH THROUGH EARLY THIS EVENING.
FIRE WEATHER
STRONG HIGH PRESSURE AND VERY HOT TEMPERATURES, WITH DRY
CONDITIONS, WILL PERSIST THROUGH THIS WEEKEND. AFTERNOON HIGH
TEMPERATURES WILL BE UP TO 112-118 DEGREES ACROSS LOWER ELEVATIONS
AND MINIMUM RH VALUES WILL BE AROUND 10-15%. TEMPERATURES THEN
DECLINE A FEW DEGREES EACH DAY THROUGH THE FIRST HALF OF THE WEEK
AND MOISTURE LEVELS WILL SLOWLY RISE. MINIMUM RHS WILL STILL BE
AROUND 15-20% MONDAY, BUT WILL INCREASE UP TO 20-30% STARTING
TUESDAY. OVERNIGHT RH RECOVERIES WILL BE FAIR TO GOOD THIS WEEKEND
AT 30-45% AND THEN INCREASE UP TO 45-70%. THE INCREASING MOISTURE
WILL RESULT IN AN INCREASE IN SHOWER AND STORM CHANCES. INITIALLY,
STORM CHANCES THIS WEEKEND THROUGH THE START OF THE WEEK WILL
FOCUS IN FAR EASTERN AND SOUTHEASTERN AZ, WITH POTENTIAL FOR STORM
OUTFLOW WINDS TO PROGRESS INTO SOUTH-CENTRAL AZ. SLIGHT CHANCES
FOR STORMS (15-30%) THEN SPREAD TO SOUTH-CENTRAL AZ BY THE MIDDLE
AND SECOND HALF OF THE WEEK. OUTSIDE OF STORM OUTFLOWS, WINDS
WILL MOSTLY FOLLOW DIURNAL PATTERNS, BUT WEST SOUTHWESTERLY WINDS
WILL BE DOMINANT MUCH OF THE TIME WITH AFTERNOON GUSTS OF 15-20
MPH AT TIMES.
CLIMATE
RECORD HIGH TEMPERATURES:
DATE PHOENIX YUMA EL CENTRO
---- ------- ---- ---------
AUG 1 116 IN 1972 117 IN 1993 118 IN 1993
AUG 2 114 IN 2025 117 IN 1918 117 IN 1969
AUG 3 116 IN 2024 116 IN 1998 117 IN 2021
PSR WATCHES/WARNINGS/ADVISORIES
AZ...EXTREME HEAT WARNING UNTIL 8 PM MST MONDAY FOR AZZ530>563.
CA...EXTREME HEAT WARNING UNTIL 8 PM PDT MONDAY FOR CAZ560>570.
SHORT TERM...SMITH
LONG TERM...BENEDICT/KUHLMAN
AVIATION...LOJERO
FIRE WEATHER...BENEDICT
CLIMATE...18
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page