415
FXUS65 KPSR 162101
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
201 PM MST MON MAR 16 2026
KEY MESSAGES
- A HISTORIC MARCH HEATWAVE IS EXPECTED THIS WEEK THROUGH THIS
WEEKEND, WITH RECORD-SHATTERING LOWER DESERT HIGH TEMPERATURES
IN THE 100S BEGINNING WEDNESDAY.
- THE EARLIEST ISSUANCE OF AN EXTREME HEAT WARNING WILL TAKE
EFFECT WEDNESDAY ACROSS SOUTHEAST CALIFORNIA AND THURSDAY ACROSS
ARIZONA DESERTS AND RUN THROUGH THIS SUNDAY.
- THE UNPRECEDENTED AFTERNOON HEAT WILL BE DANGEROUS, ESPECIALLY
WITH ANY STRENUOUS OR LONG-DURATION OUTDOOR ACTIVITIES WITHOUT
PROPER HYDRATION AND TAKING BREAKS IN SHADED OR AC COOLED AREAS.
- TEMPERATURES WILL WARM RAPIDLY BETWEEN 8 AM AND 1 PM LATE WEEK,
LIKELY EXCEEDING 90 DEGREES BEFORE NOON, FOLLOWING MORNINGS
WITH LOWS IN THE MIDDLE 60S TO LOWER 70S.
SHORT TERM /TODAY THROUGH TUESDAY/
THE STRONG HIGH PRESSURE THAT WILL DRIVE THIS WEEK'S HISTORIC
HEATWAVE HAS ALREADY DEVELOPED AND IS CENTERED JUST OFF THE
CALIFORNIA COAST. THE DESERT SOUTHWEST IS CURRENTLY ON THE EASTERN
PERIPHERY OF THIS HIGH, WITH THIN HIGH CIRRUS CRASHING DOWN FROM
THE NORTH, AFTER COMING AROUND THE TOP OF THE HIGH. WITH THE
HIGH'S CURRENT POSITIONING AND H5 HEIGHTS AROUND 582-584DAM OVER
THE REGION, WHICH IS ABOVE THE 90TH PERCENTILE OF CLIMATOLOGY,
HIGH TEMPERATURES THIS AFTERNOON WILL REACH THE LOW 90S IN SOUTH-
CENTRAL AZ TO MIDDLE 90S IN SOUTHEAST CA. THESE TEMPERATURES WILL
BE UPWARDS OF 13-17 DEGREES ABOVE NORMAL. UNFORTUNATELY, TODAY
LOOKS LIKE THE "COOLEST" DAY OF AT LEAST THE NEXT 7 DAYS.
TEMPERATURES WILL WARM ~5 DEGREES HEADING INTO TOMORROW, AS THE
CENTER OF THE HIGH NUDGES CLOSER TO THE AREA, BECOMING CENTERED
OVER LOS ANGELES BY THE END OF THE DAY. A FEW SPOTS IN SOUTHEAST
CA, THROUGH THE LOWER CO RIVER VALLEY, MAY REACH 100F FOR THE
FIRST TIME THIS YEAR TOMORROW, WITH AROUND A 50% CHANCE AT EL
CENTRO AND 25% CHANCE AT YUMA. THE HIGH TEMPERATURES THE NEXT
COUPLE OF DAYS WILL LEAD TO WIDESPREAD MINOR HEATRISK, WITH AREAS
OF MODERATE HEATRISK IN SOUTHEAST CA AND SOUTHWEST AZ. MODERATE
HEATRISK MEANS EVERYONE SENSITIVE TO HEAT IS AT RISK OF HEAT-
RELATED HEALTH IMPACTS, ESPECIALLY WITHOUT EFFECTIVE COOLING AND
HYDRATION.
BESIDES THE HEAT, THERE WILL BE SOME LINGERING BREEZINESS TODAY,
AS A RESULT OF A TIGHTENED PRESSURE GRADIENT FOLLOWING THE PASSING
SHORT-WAVE YESTERDAY. STRONGEST NORTHERLY BREEZES, GUSTS AS HIGH
AS 25-35 MPH, WILL BE ALONG THE LOWER CO RIVER VALLEY AND PARTS
OF SOUTHEAST CA. HIGHER TERRAIN SPOTS OF SOUTH-CENTRAL ARIZONA
SHOULD ALSO ANTICIPATE SOME MARGINAL BREEZES TODAY THROUGH
TOMORROW MORNING, BUT PEAK GUSTS FOR THESE LOCATIONS SHOULD HOVER
CLOSER TO 25 MPH.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
BY WEDNESDAY, THE DESERT SOUTHWEST WILL FIND ITSELF DIRECTLY UNDER
THE CENTER OF THE HIGH, WITH HEIGHTS ALOFT REACHING UPWARDS OF 592-
594DM. TO PUT THINGS INTO PERSPECTIVE, SOUNDING CLIMATOLOGY DATA
FOR LAS VEGAS, FLAGSTAFF, AND TUCSON SHOW RECORD H5 HEIGHTS FOR
MARCH ARE AROUND 590DM AND APRIL 591DM, 593DM, AND 592DM
RESPECTIVELY. THAT WOULD PUT THIS RIDGE AS ONE OF THE STRONGEST
EVER SEEN IN RECORDED HISTORY FOR THE REGION, NOT ONLY FOR MARCH,
BUT FOR APRIL AS WELL. WITH THIS SETUP, THE THERMAL PROFILE WILL
ALSO PUSH BEYOND RECORD LEVELS, WITH ALL-TIME READINGS FOR MARCH
LOOKING LIKELY AT THE H7 AND H5 LEVELS. 850MB TEMPS WILL BE CLOSE
TO ALL-TIME MARCH RECORDS BY MID TO LATE WEEK, HELPING TO PUSH
TEMPERATURES AT THE SURFACE INTO THE TRIPLE DIGITS FOR MOST OF THE
LOWER DESERTS. THE FORECAST HIGH FOR PHOENIX ON WEDNESDAY IS
TRIPLE DIGITS, WHICH IF ACHIEVED, WOULD BECOME THE EARLY INSTANCE
FOR PHOENIX, BESTING THE PREVIOUS EARLIEST (MARCH 26TH) BY 8
DAYS. MARCH 26TH, 1988 IS ACTUALLY THE ONLY MARCH DATE ON RECORD
WHERE 100 DEGREES WAS ACHIEVED IS PHOENIX, BUT SEVERAL DAYS WILL
BE ADDED TO THIS LIST THROUGH THIS HEATWAVE.
CONFIDENCE IS VERY HIGH, GIVEN SMALL MODEL SPREAD, THAT THE HIGH
WILL STRENGTHEN EVEN FURTHER BY THURSDAY WITH HEIGHTS REACHING
595-597DM, WHICH IS AROUND MAX HEIGHT FOR THE MIDDLE OF SUMMER,
AND WILL CEMENT THIS HIGH PRESSURE AS THE STRONGEST ON RECORD FOR
MARCH. THIS WILL PUSH TEMPERATURES INTO UNCHARTED TERRITORY (AT
LEAST BY LATE WINTER AND EARLY SPRING STANDARDS), BOTH AT THE
SURFACE AND THROUGHOUT THE ATMOSPHERIC COLUMN. HIGHS THURSDAY
THROUGH AT LEAST SATURDAY WILL RANGE BETWEEN 103-109 DEGREES, WITH
EVEN A LOW END CHANCE FOR A FEW LOCATIONS TO REACH 110F DURING
THIS WINDOW. THIS WOULD PUT DAILY MAXTS 25-30 DEGREES ABOVE NORMAL
AND DAILY RECORDS MAY BE BROKEN BY 5-10 DEGREES. ON THE TOPIC OF
RECORDS, THIS HEATWAVE WILL ALSO BREAK MONTHLY ALL-TIME
TEMPERATURES BY A FEW DEGREES, AS THE VALUES CURRENTLY STAND AT
100, 102, AND 101 FOR PHOENIX, YUMA, AND EL CENTRO RESPECTIVELY.
THE MONTHLY RECORDS MAY BE TIED OR BROKEN AS EARLY AS WEDNESDAY,
BUT IF NOT BY THEN THEN THEY WILL BE BROKEN ON THURSDAY.
WIDESPREAD MODERATE HEATRISK WILL DEVELOP ACROSS THE REGION IN
RESPONSE TO THE HISTORIC HEAT, WITH EVEN SOME LOCALIZED AREAS OF
MAJOR HEATRISK NOT OUT OF THE QUESTION. THE EXTREME HEAT WATCH HAS
BEEN UPGRADED TO A WARNING, BEGINNING WEDNESDAY ACROSS SOUTHEAST
CA AND THURSDAY FOR AZ DESERTS. THE WARNING WILL RUN THROUGH
SUNDAY. THIS WILL BE THE EARLIEST HEAT WARNING ON RECORD, SINCE
HEAT PRODUCTS STARTED, WITH THE CURRENT EARLIEST INSTANCE
OCCURRING BETWEEN APRIL 26TH AND 30TH OF 2020. ONE, SOMEWHAT
POSITIVE, TAKEAWAY FROM THIS HEATWAVE IS THAT THE SUN ANGLE IS
LOWER AND LENGTH OF DAY IS SHORTER THAN DURING THE SUMMER. FOR
THIS REASON, THERE WILL BE RELIEF FROM THE DAYTIME HEAT DURING THE
OVERNIGHT AND MORNING HOURS. MORNING LOW TEMPERATURES WILL LIKELY
BREAK DAILY WARM LOW RECORDS AS WELL, BUT LOWS IN THE 60S TO LOW
70S WILL OFFER MORE RELIEF THAN THE 80S TO LOW 90S SEEN DURING
THE SUMMER. IT IS IMPORTANT TO NOTE THOUGH TO NOT GET FOOLED BY
THE NICE MORNINGS AND AVOID GETTING CAUGHT OFF GUARD BY THE RAPID
HEATING FROM MID-MORNING THROUGH EARLY-AFTERNOON. TEMPERATURES
WILL WARM VERY FAST BETWEEN 8 AM AND 1 PM, WITH TEMPERATURES LATE
WEEK LIKELY REACHING THE 90S BEFORE NOON.
WHEN WILL THE HEATWAVE END? WELL, THERE IS A GOOD SIGNAL THAT
THIS HISTORIC HIGH PRESSURE WILL WEAKEN AND FLATTEN OUT LATE-
WEEKEND THROUGH EARLY NEXT WEEK, WITH POTENTIALLY A SHORTWAVE
TROUGH MOVING THROUGH THE REGION, BUT COMING OUT OF A HISTORIC
HEATWAVE IT WILL TAKE A STRONG LOW TO COOL THINGS DOWN
SIGNIFICANTLY AND THERE IS CURRENTLY NO SIGN OF ONE IN THE
EXTENDED OUTLOOK. SO, WITH THE CHANGE EARLY NEXT WEEK, THERE IS A
GOOD CHANCE HIGH TEMPERATURES WILL FALL BACK BELOW 100 (60-80%
CHANCE), BUT HIGHS LOOK TO REMAIN ABOVE 90 DEGREES THROUGH THE END
OF THE WEEK, WITH NBM ODDS OF >90F AT 80-90% CHANCE.
THIS MIGHT BE A RECORD NUMBER OF USES OF THE WORD "RECORD" IN AN
AFD.
AVIATION
UPDATED AT 1730Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT; AND
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO SIGNIFICANT WEATHER ISSUES WILL EXIST THROUGH MONDAY NIGHT UNDER
THIN, HIGH CIRRUS DECKS. CONFIDENCE IS GOOD THAT WIND TRENDS WILL
TEND TO FOLLOW THEIR TYPICAL DIURNAL TENDENCIES ACROSS THE
PHOENIX METRO. SPEEDS WILL GENERALLY BE AOB 10 KT, BUT SOME
OCCASIONAL GUSTS INTO THE TEENS ARE POSSIBLE THIS AFTERNOON. A
SLIGHTLY EARLIER SWITCH TO EASTERLY IS ANTICIPATED THIS EVENING,
AROUND 02-04Z. NORTH WINDS WILL BE FAVORED OVER SE CALIFORNIA
WITH LIGHT NOCTURNAL WESTERLIES AT KIPL AND AFTERNOON GUSTS
20-30KT COMMON AT KBLH.
FIRE WEATHER
A HISTORIC HIGH PRESSURE WILL LEAD TO RECORD TEMPERATURES, VERY
DRY CONDITIONS, SEASONAL WINDS, AND MOSTLY SUNNY SKIES THROUGH THE
NEXT WEEK. HIGH TEMPERATURES WILL BE 10-15 DEGREES ABOVE NORMAL
TODAY BEFORE INCREASING TO 25-30 DEGREES ABOVE NORMAL FROM MIDWEEK
THROUGH THIS WEEKEND. ABNORMALLY HOT AND VERY DRY CONDITIONS WILL
TRANSLATE TO MINRH NEAR 10% THE NEXT FEW AFTERNOONS BEFORE
READINGS DROP CLOSER TO 5-10% WEDNESDAY THROUGH THIS WEEKEND.
OVERNIGHT RECOVERIES WILL NOT BE GREAT, WITH VALUES AROUND 20-40%
THROUGH WEDNESDAY MORNING BEFORE DROPPING TO 15-35% THROUGH THE
REMAINDER OF THE WEEK. BREEZY TO LOCALLY WINDY CONDITIONS ARE
ONGOING TODAY AND WILL CONTINUE THROUGH TONIGHT, MAINLY OVER THE
ARIZONA HIGH TERRAIN AND THE LOWER COLORADO RIVER VALLEY, WITH THE
STRONGEST GUSTS (25-35 MPH) FOCUSED OVER THE LATTER AREA. THE
BREEZY CONDITIONS, COMBINED WITH LOW RH VALUES WILL RESULT IN
ELEVATED TO ISOLATED AREAS OF CRITICAL FIRE WEATHER CONDITIONS.
HOWEVER, WITH THE LIMITED SCOPE OF ENHANCED WINDS, NO FIRE WEATHER
PRODUCTS ARE NEEDED AT THIS TIME.
CLIMATE...
DAILY RECORD HIGHS THROUGH NEXT WEEKEND:
DATE PHOENIX YUMA EL CENTRO
---- ------- ---- ---------
3/16 99 IN 2007 99 IN 2007 100 IN 2007
3/17 99 IN 2007 101 IN 2007 101 IN 2007
3/18 95 IN 2017 96 IN 2017 95 IN 2007
3/19 96 IN 2017 98 IN 2017 96 IN 2017
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
PSR WATCHES/WARNINGS/ADVISORIES
AZ...EXTREME HEAT WARNING FROM 11 AM WEDNESDAY TO 8 PM MST SUNDAY FOR
AZZ530.
EXTREME HEAT WARNING FROM 11 AM THURSDAY TO 8 PM MST SUNDAY FOR
AZZ531>555-559-561.
CA...EXTREME HEAT WARNING FROM 11 AM WEDNESDAY TO 8 PM PDT SUNDAY FOR
CAZ561>570.
SHORT TERM...BENEDICT
LONG TERM...BENEDICT/RW
AVIATION...BERISLAVICH
FIRE WEATHER...BENEDICT
CLIMATE...18/KUHLMAN
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