250
FXUS65 KPSR 212058
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
158 PM MST SAT MAR 21 2026
KEY MESSAGES
- RECORD BREAKING LOWER DESERT HIGH TEMPERATURES NEAR 100 DEGREES
WILL BE COMMON THROUGH THE UPCOMING WORK WEEK, WITH THE HOTTEST
OF THE NEXT 7 DAYS LIKELY TODAY.
- EXTREME HEAT WARNINGS WILL REMAIN IN EFFECT ACROSS THE LOWER
DESERTS THROUGH SUNDAY.
- THE UNPRECEDENTED AFTERNOON HEAT WILL BE DANGEROUS, ESPECIALLY
WITH ANY STRENUOUS OR LONG-DURATION OUTDOOR ACTIVITIES WITHOUT
PROPER HYDRATION AND TAKING BREAKS IN THE SHADE, OR AIR
CONDITIONING.
SHORT TERM /TODAY THROUGH MONDAY/
MIDLEVEL WATER VAPOR IMAGERY AND 500 MB RAP ANALYSIS SHOW THE
CORE OF THIS IMPRESSIVELY STRONG RIDGE NOW OVER THE VAST PORTION
OF SOUTHEASTERN ARIZONA. EVEN THOUGH THE CORE IS NOT DIRECTLY OVER
OUR REGION, VERY POSITIVE HEIGHT ANOMALIES REMAIN OVER ALL OF THE
CONUS, ESPECIALLY OVER WESTERN CONUS AND THE DESERT SW. THESE 500
MB HEIGHTS ARE IN THE 99TH TO NEAR MAX PERCENTILE OF CLIMATOLOGY,
WITH EVEN THE 700 MB HEIGHTS ABOVE THE 97TH PERCENTILE OF CLIMATOLOGY
FOR TODAY. THIS WILL LEAD TO THIS AFTERNOON'S TEMPERATURES ACROSS
THE LOWER DESERTS TO RANGE BETWEEN 102F-108F. THIS IS ALMOST IDENTICAL
TO YESTERDAY'S TEMPERATURES, SO YET AGAIN, WE CAN EXPECT PREVIOUS
RECORD HIGHS ACROSS THE REGION TO BE BROKEN BY 5F-10F. BY SUNDAY,
HEIGHTS ALOFT WILL DECREASE SLIGHTLY TO BETWEEN 582-585 DAM DUE
TO SEVERAL SHORTWAVES PROGRESSING OVER CANADA AND THE NORTHWESTERN
STATES. THIS WILL HELP FLATTEN THE RIDGE OVER THE DESERT SW
CAUSING TEMPERATURES TO COOL 2F-5F FOR TOMORROW AND EARLY INTO THE
WORKWEEK, WITH MONDAY LOOKING TO BE THE "COOLEST" DAY WITH ONLY A
~40% CHANCE OF HITTING 100F AT PHOENIX SKY HARBOR. HOWEVER, EVEN
WITH A SLIGHT DROP, THESE TEMPERATURES WILL REMAIN 15F-20F ABOVE
NORMAL FOR THIS TIME OF YEAR, AND THE EXTREME HEAT WARNINGS WILL
REMAIN IN EFFECT ACROSS THE LOWER DESERTS THROUGH SUNDAY.
AS THE CORE OF THE RIDGE CONTINUES SHIFTING TO THE SOUTHEAST OVER
THE WEEKEND, AN APPROACHING WEAK DISTURBANCE FROM THE WEST WILL
ALSO BEGIN TO IMPACT SOUTHEAST CA AND SOUTHWEST AZ BY THIS
EVENING INTO SUNDAY MORNING. THIS DISTURBANCE WILL LEAD TO AN
INCREASE BREEZY CONDITIONS IN THESE AREAS, WITH GUSTS LIKELY
BETWEEN 20-25 MPH, WITH LOCALLY HIGHER SPEEDS POSSIBLE. BREEZY
CONDITIONS, WITH GUSTS NEAR 20 MPH IN THE LATE AFTERNOON AND
EARLY EVENING HOURS, WILL CONTINUE THROUGH EARLY NEXT WEEK,
PREDOMINATELY OUT IN SOUTHEAST CA, AND IN THE IMPERIAL VALLEY.
LONG TERM /TUESDAY THROUGH FRIDAY/
DURING THE MIDDLE OF THE UPCOMING WORKWEEK, ENSEMBLES REMAIN IN
EXCELLENT AGREEMENT THAT ANOTHER SIGNIFICANT YET MORE TRANSIENT
RIDGING FEATURE WILL BUILD UNDER AN ANTICYCLONICALLY CURVED JET
STREAK. THOUGH THE RIDGING WILL BE LOWER AMPLITUDE COMPARED TO THE
CURRENT RIDGE, AND ANTICYCLONIC SUBSIDENCE WILL BE SHORTER LIVED
(LIKELY PEAKING IN ITS INFLUENCE SOMETIME TUESDAY-WEDNESDAY), H5
HEIGHTS ARE FORECAST TO RISE INTO A 587-590 DAM RANGE - ONCE
AGAIN ABOVE CFSR CLIMATOLOGICAL MAXIMUM VALUES FOR THIS TIME OF
YEAR. THIS WILL ALLOW TEMPERATURES TO WARM FOR THE LATTER HALF OF
THE WORKWEEK, WITH HIGHS HOVERING IN THE UPPER 90S TO LOWER 100S
ACROSS THE LOWER DESERTS. LATEST PROBABILISTIC NBM OUTPUT
ADVERTISES IQRS OF 4F OR LESS FOR THE FORECAST TEMPERATURES DURING
THIS TIMEFRAME, YIELDING GOOD CONFIDENCE IN THIS ABNORMAL MARCH
HEATWAVE STICKING AROUND AND DAILY HIGHS STAYING IN RECORD
TERRITORY THROUGH AT LEAST THE NEXT 7 DAYS.
AVIATION
UPDATED AT 1730Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT; AND
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO AVIATION WEATHER CONCERNS ARE EXPECTED DURING THE TAF PERIOD.
WINDS WILL CONTINUE TO FOLLOW FAMILIAR DIURNAL PATTERNS AT THE
PHOENIX METRO TERMINALS WITH SPEEDS REMAINING AOB 8 KTS. AT THE
SE CALIFORNIA TERMINALS, EXPECT PREDOMINANTLY WESTERLY WINDS AT
KIPL AND SOUTHWESTERLY WINDS AT KBLH. INTERMITTENT GUSTS UP TO
AROUND 25 KTS CAN BE ANTICIPATED AT KIPL THIS EVENING. CLEAR SKIES
WILL GIVE WAY TO INCREASING HIGH CIRRUS DECKS LATER THIS EVENING.
FIRE WEATHER
RECORD BREAKING HEAT AND DRY CONDITIONS WILL CONTINUE THROUGH
NEXT WEEK. AFTERNOON HIGHS AROUND 25 DEGREES ABOVE DAILY NORMALS
WILL BE COMMON TODAY, FALLING TO AROUND 15 TO 20 DEGREES ABOVE
NORMAL BY MONDAY. AFTERNOON MINRHS BETWEEN 5-10% WILL PERSIST
THROUGH SUNDAY, INCREASING SLIGHTLY INTO A 10-20% RANGE FOR PORTIONS
OF THE WESTERN DESERTS EARLY NEXT WEEK, BUT DRYING THROUGHOUT THE
WORKWEEK. OVERNIGHT RECOVERIES WILL BE POOR, AROUND 15-35% AREAWIDE
TONIGHT. OVERNIGHT RECOVERIES IMPROVE TO 40-60% SUNDAY THROUGH
TUESDAY NIGHT PRIMARILY FOR VALLEY LOCATIONS IN THE WESTERN DESERTS
LIKE THE YUMA AREA, LOWER COLORADO RIVER VALLEY, IMPERIAL VALLEY,
AND LOWER GILA RIVER VALLEY. ELSEWHERE, MAXRHS WILL RANGE BETWEEN
25-40% INTO THE MIDDLE OF THE WORK WEEK. LATE AFTERNOON AND EARLY
EVENING BREEZINESS WILL INCREASE THIS WEEKEND INTO EARLY NEXT
WEEK, WITH GUSTS LOCALLY TO 20-25 MPH IN THE WESTERN DISTRICTS.
CLIMATE
DAILY RECORD HIGHS THROUGH THE UPCOMING WORK WEEK:
DATE PHOENIX YUMA EL CENTRO
---- ------- ---- ---------
3/21 97 IN 2004 102 IN 2004 100 IN 2004
3/22 94 IN 1990 98 IN 2004 96 IN 2004
3/23 93 IN 1990 96 IN 1990 93 IN 1990
3/24 96 IN 2025 97 IN 2025 96 IN 2025
3/25 99 IN 2025 99 IN 1896 99 IN 2025
3/26 100 IN 1988 99 IN 1988 98 IN 1988
3/27 98 IN 1986 100 IN 1986 99 IN 1988
PSR WATCHES/WARNINGS/ADVISORIES
AZ...EXTREME HEAT WARNING UNTIL 8 PM MST SUNDAY FOR AZZ530>555-559-
561.
CA...EXTREME HEAT WARNING UNTIL 8 PM PDT SUNDAY FOR CAZ561>570.
SHORT TERM...RYAN
LONG TERM...WHITTOCK
AVIATION...SALERNO
FIRE WEATHER...WHITTOCK/RYAN
CLIMATE...WHITTOCK/18
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page