229
FXUS65 KPSR 091125
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
425 AM MST SAT MAY 9 2026
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- AN EXTREME HEAT WARNING WILL BE IN EFFECT FOR PHOENIX AND
PORTIONS OF SOUTHEAST CALIFORNIA ON SUNDAY AND MONDAY.
- MODERATE HEATRISK WILL IMPACT THE MAJORITY OF THE AREA THROUGH
TUESDAY WITH ISOLATED MAJOR HEATRISK SUNDAY AND MONDAY.
- MONDAY IS EXPECTED TO BE THE HOTTEST DAY WITH LOWER DESERT HIGH
TEMPERATURES PEAKING BETWEEN 105 AND 110 DEGREES.
SHORT TERM /TODAY THROUGH MONDAY/
UPPER LEVEL RIDGING IS NOW FULLY IN CONTROL ACROSS THE
SOUTHWESTERN U.S. PROVIDING HOT TEMPERATURES AND DRY CONDITIONS.
THE CENTER OF THE RIDGE WILL REMAIN OFFSHORE TODAY AND FOR THE
FIRST PART OF SUNDAY BEFORE MOVING DIRECTLY OVERHEAD LATE SUNDAY
THROUGH THE FIRST PART OF MONDAY. THE CURRENT H5 HEIGHTS OF
581-583DM ALONG WITH AN ALREADY VERY WARM BOUNDARY LAYER WILL
ALLOW FOR EVEN HOTTER DAYTIME TEMPERATURES TODAY WITH READINGS
BETWEEN 101-104 DEGREES IN THE PHOENIX AREA TO 103-106 DEGREES
ACROSS SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA. AS THE CENTER
OF THE RIDGE BEGINS TO MOVE INTO THE REGION FROM THE WEST ON
SUNDAY, H5 HEIGHTS WILL RISE TO 585-587DM BEFORE PEAKING BETWEEN
588-591DM ON SUNDAY.
BETWEEN NOW AND MONDAY, GUIDANCE INDICATES H8 TEMPERATURES WARMING
ANOTHER 4C, PEAKING NEAR 30C ON MONDAY. THIS WARMING ALOFT IS
EXPECTED TO EASILY MIX DOWN THROUGH THE BOUNDARY LAYER WITH THE
BIGGEST CHANGE IN TEMPERATURES FROM SUNDAY INTO MONDAY. FORECAST
HIGHS HAVE BARELY CHANGED OVER THE PAST SEVERAL FORECAST PACKAGES
AND STILL CALL FOR 103-107 DEGREES SUNDAY AND 106-110 MONDAY.
BOTH DAYS WILL REPRESENT A HIGH-END MODERATE HEATRISK FOR NEARLY
ALL LOCATIONS ACROSS SOUTHEAST CALIFORNIA THROUGH SOUTHERN AND
CENTRAL ARIZONA WITH MONDAY HAVING THE HIGHEST AREAL COVERAGE
(~25%) OF MAJOR HEATRISK. AN EXTREME HEAT WARNING HAS BEEN ISSUED
FOR WESTERN PORTIONS OF IMPERIAL COUNTY AND FOR THE PHOENIX METRO
ON SUNDAY AND MONDAY.
LONG TERM /TUESDAY THROUGH FRIDAY/
A GRADUAL CHANGE IN THE UPPER LEVEL PATTERN WILL HELP TO BRING
SOME MODEST HEAT RELIEF BY THE LATTER HALF OF NEXT WEEK. THE FIRST
CHANGE WILL BE A WEAK TROUGH THAT IS FORECAST TO DEVELOP JUST
WEST OF SOUTHERN BAJA ON SUNDAY BEFORE TRACKING NORTHWARD ALONG
THE CALIFORNIA COASTLINE ON TUESDAY. THIS FEATURE IS NOT EXPECTED
TO BRING BIG CHANGES TO OUR REGION, BUT IT WILL LEAD TO INCREASED
SOUTHERLY FLOW AND MOISTURE WHILE ALSO SOMEWHAT DISPLACING THE
RIDGE TO OUR EAST. MODELS SHOW DECENT MOISTURE ADVECTION MAINLY
ABOVE 15K FEET INTO OUR REGION STARTING MONDAY NIGHT, BUT MORE SO
TUESDAY NIGHT INTO WEDNESDAY. TUESDAY MAY BRING SOME SPARSE
HIGHER LEVEL CLOUDS, BEFORE THICKER AND MORE CLOUD COVERAGE IS
LIKELY TO MOVE IN ON WEDNESDAY.
THE TRACK OF THE SHORTWAVE TROUGH ACROSS CALIFORNIA TUESDAY AND
WEDNESDAY IS ALSO EXPECTED TO LOWER HEIGHTS ACROSS THE DESERT
SOUTHWEST, BUT ANY COOLING WILL BE SLOW TO OCCUR. TUESDAY'S
FORECAST HIGHS ARE VERY SIMILAR TO SUNDAY'S EXPECTED READINGS, BUT
BY WEDNESDAY HIGHS ARE LIKELY TO FALL BACK TO JUST ABOVE 100
DEGREES. A LARGER, BUT WEAKENING PACIFIC LOW IS THEN EXPECTED TO
REACH THE CALIFORNIA COAST SOMETIME WEDNESDAY INTO WEDNESDAY NIGHT
BEFORE MOVING EAST NORTHEAST THROUGH NEVADA AND UTAH ON THURSDAY
AND/OR FRIDAY OF NEXT WEEK. THIS DISTURBANCE SHOULD CONTINUE TO
AID IN WEAK HEIGHT FALLS ACROSS THE DESERT SOUTHWEST LATE NEXT
WEEK POTENTIALLY DROPPING DAYTIME HIGHS INTO THE UPPER 90S, OR
AROUND FIVE DEGREES ABOVE NORMAL.
AVIATION
UPDATED AT 1124Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO AVIATION WEATHER CONCERNS UNDER MOSTLY CLEAR SKIES CAN BE
EXPECTED THROUGHOUT THE TAF PERIOD. THE OVERALL WIND PATTERN WILL
CONTINUE TO EXHIBIT THE TYPICAL DIURNAL TENDENCIES WITH SPEEDS AOB
12 KTS, ALTHOUGH OCCASIONAL GUSTS NEAR 20 KTS WILL BE COMMON THIS
AFTERNOON THROUGH EARLY EVENING.
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, WINDS WILL GENERALLY
PREVAIL OUT OF THE WEST, WITH THE EXCEPTION OF A PERIOD
SOUTHEASTERLY WINDS DURING THE EARLY TO MID-AFTERNOON HOURS. AT
KBLH, WINDS WILL GENERALLY FLUCTUATE OUT OF THE SOUTH TO SOUTHWEST
DURING THE DAY AND VEER NORTH LATE TONIGHT. OVERALL WIND SPEEDS
WILL BE AOB 12 KTS, ALTHOUGH SOME GUSTS UPWARDS OF 20-25 KTS ARE
ANTICIPATED AT KIPL FOR A FEW HOURS THIS EVENING.
FIRE WEATHER
HOT AND DRY CONDITIONS WILL PREVAIL WELL INTO NEXT WEEK WITH LOWER
DESERT HIGHS TOPPING 100 DEGREES THROUGH AT LEAST TUESDAY. WITH
AFTERNOON HIGHS WARMING 10-15 DEGREES ABOVE NORMAL, MINIMUM
HUMIDITY LEVELS WILL MOSTLY FALL INTO THE SINGLE DIGITS EACH DAY.
CORRESPONDINGLY, OVERNIGHT RECOVERY WILL ONLY BE IN A POOR TO
FAIR 20-35% RANGE. WINDS WILL BE VERY TYPICAL FOR MID MAY THROUGH
MONDAY WITH SOME GUSTS AROUND 20 MPH COMMON DURING MID/LATE
AFTERNOON. THE COMBINATION OF THE HOT TEMPERATURES, VERY LOW RHS,
DRY FUELS, AND BREEZY CONDITIONS FOCUSED DURING THE LATE
AFTERNOON HOURS SHOULD RESULT IN ELEVATED FIRE WEATHER CONDITIONS
FOR PORTIONS OF THE AREA.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...EXTREME HEAT WARNING FROM 10 AM SUNDAY TO 8 PM MST MONDAY FOR
AZZ537-540-542>544-546-548-550-551.
CA...EXTREME HEAT WARNING FROM 10 AM SUNDAY TO 8 PM PDT MONDAY FOR
CAZ562-563-566.
SHORT TERM...KUHLMAN
LONG TERM...KUHLMAN
AVIATION...BENEDICT/LOJERO
FIRE WEATHER...KUHLMAN
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