092
FXUS65 KPSR 201050
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
350 AM MST FRI MAR 20 2026
UPDATE
12Z AVIATION DISCUSSION
KEY MESSAGES
- RECORD BREAKING LOWER DESERT HIGH TEMPERATURES NEAR OR
EXCEEDING 100 DEGREES WILL BE COMMON THROUGH AT LEAST THE MIDDLE
OF NEXT WEEK, WITH THE HOTTEST DAYS BEING TODAY AND SATURDAY.
- 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 SUNDAY/
THE UNPRECEDENTED MARCH HEATWAVE CONTINUES, WITH MONTHLY HIGH
TEMPERATURE RECORDS BEING SURPASSED ONCE AGAIN AT OUR THREE MAJOR
CLIMATE SITES (PHOENIX, YUMA, AND EL CENTRO) ON THURSDAY. CURRENT
500 MB RAP ANALYSIS AND MIDLEVEL WATER VAPOR IMAGERY SHOW THE CENTER
OF AN IMPRESSIVELY SYMMETRICAL AND STRONG RIDGE OF HIGH PRESSURE
OVER SOUTHWEST AZ, WHICH IS RESPONSIBLE FOR THE RECORD SETTING
HEAT ACROSS THE SOUTHWEST US. ENSEMBLES REMAIN IN EXCELLENT
AGREEMENT THAT THE STRENGTH OF THE RIDGE WILL WANE GOING FORWARD,
BUT TO A LARGE DEGREE IT HAS ALREADY MODIFIED LOW LEVEL THERMAL
PROFILES TO DEVELOP A RECORD WARM (FOR THE TIME OF YEAR) AND VERY
DRY AIRMASS OVER THE REGION, ONE WHICH WILL REMAIN WITH US THROUGH
AT LEAST THE MIDDLE OF THE UPCOMING WORK WEEK. MIDLEVEL HEIGHTS
WILL DECREASE MORE NOTICEABLY THIS WEEKEND, STARTING SATURDAY BUT
ESPECIALLY ON SUNDAY, AS A FEW NORTHERN STREAM SHORTWAVE TROUGHS
OVERTOP THE RIDGE AND ACT TO DISLODGE THE CENTER OF THE
ANTICYCLONE FURTHER EAST.
FORECAST HIGHS TODAY ARE EXPECTED TO BE THE HOTTEST OF THE ENTIRE
EVENT, PEAKING IN A 102F-108F RANGE ACROSS THE LOWER DESERTS.
DESPITE MIDLEVEL HEIGHTS FALLING ON SATURDAY, LOWER TROPOSPHERIC
TEMPERATURES WILL NOT RESPOND AS QUICKLY AS THE MID TO UPPER LEVELS,
AND SO ANTICIPATE SIMILAR OR PERHAPS 1F-2F LOWER HIGHS ON SATURDAY.
THEREFORE, HIGHS WILL CONTINUE AROUND 25F ABOVE DAILY NORMALS AND 4F-
10F ABOVE DAILY RECORDS THROUGH SATURDAY. ENSEMBLE MEAN H5 HEIGHTS
WILL BOTTOM OUT ON SUNDAY IN A 583-585 DAM RANGE. THIS IS STILL AT
OR ABOVE THE 97TH PERCENTILE OF CLIMATOLOGY, BUT IT SHOULD ALLOW FOR
HIGHS TO DROP BY SEVERAL DEGREES, FALLING INTO A 96F-102F RANGE
ACROSS THE LOWER DESERTS ON SUNDAY. THESE TEMPERATURES REPRESENT
VALUES AROUND 20F ABOVE DAILY NORMALS AND STILL ABOVE DAILY RECORDS
FOR MANY LOCATIONS (SEE CLIMATE SECTION FOR MORE DETAILS).
CONSIDERING THE CLIMATOLOGICAL CONTEXT, THE TIMING OF THE EVENT
WHICH COINCIDES WITH A WEEKEND, AND MANY OUT-OF-STATE VISITORS AND
EVEN LOCALS WHO ARE NOT ACCLIMATED TO THIS LEVEL OF HEAT, THIS EVENT
WILL CONTINUE TO BE IMPACTFUL. EXTREME HEAT WARNINGS WILL REMAIN IN
EFFECT ACROSS THE LOWER DESERTS THROUGH SUNDAY. IT IS TRUE THAT WE
EXPERIENCE THIS LEVEL OF HEAT EVERY YEAR IN THIS PART OF THE
COUNTRY, BUT IT IS MUCH MORE TYPICAL FOR THE MONTH OF JUNE; DO NOT
FORGET THAT THIS LEVEL OF HEAT IS UNPRECEDENTED THIS EARLY IN THE
YEAR AND CAN BE DANGEROUS IF YOU DO NOT TAKE PROPER HEAT SAFETY
PRECAUTIONS.
ASIDE FROM THE HEAT, WINDS ALOFT WILL INCREASE SOMEWHAT ACROSS THE
REGION AS THE RIDGE IS DAMPENED AND SHIFTS SLIGHTLY EASTWARD THIS
WEEKEND. ENSEMBLE MEAN 700 MB WINDS INCREASE TO AROUND 15-20 KTS OUT
OF THE SOUTHWEST, PARTICULARLY LATE SATURDAY. WHILE THIS IS NOT
IMPRESSIVE, DEEPER MIXING DURING THE LATE AFTERNOON/EARLY EVENING
MAY BE ABLE TO TAP INTO THIS HIGHER MOMENTUM AIR AND PRODUCE GUSTS
TO AROUND 20-25 MPH ACROSS SOME OF THE AREA, PARTICULARLY PORTIONS
OF SOUTHEAST CA LIKE IMPERIAL COUNTY.
LONG TERM /MONDAY THROUGH THURSDAY/
OF THE NEXT 7 DAYS, MONDAY IS SHAPING UP TO BE THE "COOLEST" (LOWER
DESERT HIGHS 94F-101F) THANKS TO A COUPLE OF FACTORS. THE RIDGE WILL
NOT REBUILD SUBSTANTIALLY UNTIL TUESDAY OVER THE DESERT SOUTHWEST
AND LOWER LEVEL THERMAL PROFILE WILL REQUIRE STRONGER/SUSTAINED
ANTICYCLONIC SUBSIDENCE TO WARM FURTHER. ANOTHER FACTOR IS THAT
GUIDANCE INDICATES SOMETHING REMINISCENT OF A GULF SURGE
OCCURRING SUNDAY NIGHT AND POSSIBLY AGAIN MONDAY NIGHT, INCREASING
MOISTURE OVER A SHALLOW LAYER NEAR THE SURFACE. DEWPOINT
TEMPERATURES ARE SHOWN INCREASING UPWARDS OF 45F-55F FOR THE YUMA
AREA AND AT TIMES FOR THE ADJACENT VALLEYS (IMPERIAL, LOWER
COLORADO RIVER, LOWER GILA RIVER). DEWPOINTS ARE FORECAST TO
INCREASE AT LEAST INTO THE 30S ELSEWHERE ACROSS THE LOWER DESERTS.
IT WILL BE HARDER TO REALIZE WIDESPREAD TEMPERATURES IN EXCESS OF
100F ESPECIALLY ON MONDAY THANKS TO THESE FACTORS.
DURING THE MIDDLE OF NEXT WEEK, ENSEMBLES CONTINUE TO ADVERTISE
ANOTHER SIGNIFICANT YET MORE TRANSIENT RIDGING FEATURE BUILDING
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 588-591 DAM RANGE - ONCE AGAIN ABOVE CFSR CLIMATOLOGICAL
MAXIMUM VALUES OVER A BROAD AREA. THIS WILL ALLOW A GRADUAL
WARMING INTO THE MIDDLE OF THE UPCOMING WORKWEEK, WITH COVERAGE OF
100F+ TEMPERATURES INCREASING. IN SUMMARY, CONFIDENCE CONTINUES
TO GROW IN A LONGER DURATION HEATWAVE, WITH HIGHS REMAINING
BETWEEN 15F-25F ABOVE DAILY NORMALS AND BREAKING DAILY RECORDS
WELL INTO NEXT WEEK.
AVIATION
UPDATED AT 1050Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT; AND
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO AVIATION CONCERNS ARE EXPECTED DURING THE TAF PERIOD. WINDS
WILL CONTINUE TO FOLLOW SIMILAR TRENDS SEEN OVER THE PAST 24 HOURS
WITH SPEEDS GENERALLY AOB 10KT. EXTENDED PERIODS OF VRB TO CALM
CONDITIONS WILL BE COMMON, ESPECIALLY FOR THE WESTERN TERMINALS.
CLEAR SKIES WILL DOMINATE THE REGION THROUGH SATURDAY MORNING.
FIRE WEATHER
HISTORIC MARCH HEAT AND VERY DRY CONDITIONS WILL CONTINUE INTO THE
WEEKEND. AFTERNOON HIGHS AROUND 25 DEGREES ABOVE DAILY NORMALS
WILL BE COMMON THROUGH SATURDAY, FALLING TO AROUND 20 DEGREES
ABOVE NORMAL BY SUNDAY. 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. OVERNIGHT
RECOVERIES WILL BE POOR, AROUND 15-35% THROUGH SATURDAY NIGHT, AND
THEN IMPROVE SUNDAY NIGHT AND MONDAY NIGHT PRIMARILY FOR VALLEY
LOCATIONS IN THE WESTERN DESERTS LIKE THE YUMA AREA, LOWER COLORADO
RIVER VALLEY, IMPERIAL VALLEY, AND LOWER GILA RIVER VALLEY.
WINDS WILL BE LIGHT TODAY, MOSTLY BELOW 15 MPH, BUT LATE
AFTERNOON AND EARLY EVENING BREEZINESS WILL INCREASE THIS WEEKEND,
WITH GUSTS LOCALLY TO 20-25 MPH.
CLIMATE
DAILY RECORD HIGHS THROUGH THE MIDDLE OF NEXT WEEK:
DATE PHOENIX YUMA EL CENTRO
---- ------- ---- ---------
3/20 96 IN 2017 99 IN 2004 98 IN 2004
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
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...WHITTOCK
LONG TERM...WHITTOCK
AVIATION...RW
FIRE WEATHER...WHITTOCK
CLIMATE...WHITTOCK/18
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