676
FXUS65 KPSR 220815
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
115 AM MST WED JUL 22 2026
KEY MESSAGES
- TEMPERATURES WILL INCREASE SIGNIFICANTLY THE REMAINDER OF THE WEEK
WITH EXTREME HEAT WARNINGS IN EFFECT AS READINGS APPROACH NEAR
RECORD LEVELS.
- HIGH PRESSURE RESPONSIBLE FOR THE EXTREME HEAT WILL ALSO RESTRICT
THUNDERSTORM DEVELOPMENT WITH CHANCES RETREATING WELL INTO THE
MOUNTAINS THROUGH THE WEEKEND.
- ABOVE NORMAL TEMPERATURES MAY BEGIN TO RELAX EARLY NEXT WEEK AS
BETTER THUNDERSTORM COVERAGE RETURNS TO THE REGION.
SHORT TERM /TODAY THROUGH FRIDAY/
A WELL DEFINED EASTERLY WAVE, NOW IN THE FORM OF A CLOSED
CIRCULATION WAS SLOWLY MIGRATING NORTH ALONG THE ARIZONA/NEW MEXICO
BORDER EARLY THIS MORNING. WITH THIS EVOLUTION, FAVORABLE DIVERGENCE
ALOFT AND DOWNSTREAM VORTICITY ADVECTION ON THE NORTHERN AND WESTERN
PERIPHERY OF THE GYRE WERE EXITING THE FORECAST AREA. IN ITS PLACE
AS THE VORTICITY CENTER EJECTS INTO THE CENTRAL ROCKIES, DEEPER NW
FLOW AND SUBSIDENCE WILL BECOME MORE PRONOUNCED OVER THE NEXT 36
HOURS AS SUBTROPICAL RIDGING RETROGRADES FROM THE SOUTHERN PLAINS.
WHILE THIS PATTERN WILL NOT COMPLETELY SCOUR AWAY MOISTURE, THE
CURRENT 10-14 G/KG BOUNDARY LAYER MIXING RATIOS WILL BE REPLACED BY
9-10 G/KG LEVELS. COINCIDENT WITH NOTABLE WARMING ALOFT, THIS WILL
HEIGHTEN CINH AND LIMIT AVAILABLE MLCAPE SUCH THAT EVEN DEEP
CONVECTION OVER HIGHER TERRAIN LOCATIONS MAY STRUGGLE. HREF OUTPUT
REFLECTS THIS WITH ONLY ISOLATED PULSE DRIVEN DEEP CONVECTION THIS
AFTERNOON, FOLLOWED BY ESSENTIALLY A COMPLETELY DRY FORECAST
THURSDAY AND FRIDAY.
THE LARGER WEATHER HAZARD OVER THE NEXT SEVERAL DAYS WILL BE
BUILDING HEAT AS STRONG SUBTROPICAL RIDGING RETROGRADES BACK INTO
THE SW CONUS. ENSEMBLE MEMBERS ARE IN EXCELLENT AGREEMENT DEPICTING
THE CENTRAL ANTI-CYCLONE BECOMING ESTABLISHED OVER WESTERN NEW
MEXICO BY FRIDAY WITH H5 HEIGHTS SETTLING NEAR 598DM. SURPRISINGLY
GIVEN THE AGREEMENT AMONG THE ENTIRE ENSEMBLE SUITE, NUMERICAL
SPREAD IS FAIRLY WIDE LIKELY OWING TO DIFFERENCES IN BOUNDARY LAYER
MOISTURE CONTENT ACROSS THE CWA. GIVEN THE CURRENT LOW LEVEL
DEWPOINT STATUS IN SOUTH-CENTRAL ARIZONA AND LACK OF STRONG FLOW
THROUGHOUT THE TROPOSPHERE, IT'S MORE LIKELY MODEST MOISTURE LINGERS
AND SOME OF THE MORE EXTREME FORECASTS ABOVE THE 75TH PERCENTILE
WILL NOT COME TO FRUITION. HOWEVER ACROSS THE WESTERN CWA WHERE
MOISTURE IS NOT AS PLENTIFUL, UPPER END READINGS ABOVE 115F WILL BE
MORE LIKELY. REGARDLESS, WIDESPREAD MAJOR HEATRISK (AND LOCAL
EXTREME HEATRISK) WITH AFTERNOON HIGHS 5F-10F ABOVE NORMAL WILL
BECOME COMMON, AND AN EXTREME HEAT WARNING CONTINUES.
LONG TERM /SATURDAY THROUGH TUESDAY/
STRONG HIGH PRESSURE WILL CONTINUE TO BE THE DOMINANT SYNOPTIC
FEATURE THROUGH EARLY NEXT WEEK WITH H5 HEIGHTS 596-598DM SPRAWLING
ACROSS THE FORECAST AREA. UNSURPRISINGLY GIVEN THIS PATTERN,
WIDESPREAD MAJOR HEATRISK WILL CONTINUE WITH CLEAR CUT WARNING
CRITERIA PERSISTING THROUGH THE WEEKEND AS TEMPERATURES HOVER 5F-10F
ABOVE NORMAL. THE PREPONDERANCE OF ENSEMBLE OUTPUT SUGGESTS THE
CENTER OF THE SUBTROPICAL ANTI-CYLCONE SLOWLY LIFTING THROUGH THE
FOUR CORNERS AND INTO COLORADO DURING THE FIRST PART OF NEXT WEEK
ALLOWING EASTERLY FLOW, SUBTLE SHORTWAVES, AND STRONGER, MOIST
OUTFLOWS TO RETURN TO ARIZONA. EASTERLY WAVE ENERGY WILL ALSO HELP
ERODE SOME OF THE HIGHER MIDLEVEL HEIGHTS AND TEMPERATURES WHILE
ALSO AIDING THE DISPLACEMENT OF THE ANTI-CYCLONE CENTER. THESE
COMBINED EFFORTS SHOULD ALLOW LOCAL H5 HEIGHTS TO FALL BELOW 594DM
THOUGH THE TIMING AT WHICH THIS EVOLUTION OCCURS IS SOMEWHAT
UNCERTAIN. AMONG GEFS MEMBERS, THERE IS FAIRLY CONVINCING EVIDENCE
OF ENHANCED CONVECTION SUNDAY ALLOWING DEEPER OUTFLOW INTRUSIONS
WHILE H5 HEIGHTS FALL BELOW 594DM REDUCING OR ELIMINATING THE
EXTREME HEAT THREAT MONDAY. EPS MEMBERS ARE MORE SUGGESTIVE OF
BETTER CONVECTIVE POTENTIAL DELAYED UNTIL MONDAY EVENING, BUT
REGARDLESS TEMPERATURES SHOULD RETURN TO NEAR NORMAL LEVELS BY THE
MIDDLE OF NEXT WEEK WITH THE DIURNAL THUNDERSTORM RISKS ALSO
RETURNING TO THE REGION.
AVIATION
UPDATED AT 0515Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO MAJOR AVIATION WEATHER CONCERNS ARE EXPECTED THROUGHOUT THE TAF
PERIOD. VCSH WILL PREVAIL THROUGH THE FIRST PART OF THE OVERNIGHT,
ESPECIALLY AT KDVT AND KSDL. OTHERWISE, FAIRLY TRANQUIL CONDITIONS
WILL PREVAIL THROUGH TUESDAY WITH NO OUTFLOWS/THUNDERSTORMS EXPECTED
AT THIS TIME. WINDS THROUGH TUESDAY MORNING WILL PREVAIL OUT OF THE
EAST AT LESS THAN 10 KTS WITH LIGHT WEST TO NORTHWEST EXPECTED
TUESDAY AFTERNOON, ALTHOUGH EXTENDED PERIODS OF VARIABILITY WILL BE
COMMON. SCT-BKN CLOUDS AOA 10 KFT WILL BE COMMON THROUGH THE
OVERNIGHT WITH COVERAGE DECREASING TO FEW THROUGHOUT THE DAY
TUESDAY.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR AVIATION WEATHER ISSUES UNDER FEW PASSING MID/HIGH CLOUD
DECKS CAN BE EXPECTED THROUGHOUT THE TAF PERIOD. WINDS WILL
GENERALLY BE OUT OF THE WEST AT KIPL AND OUT OF THE SOUTH TO
SOUTHEAST AT KBLH THROUGH THE OVERNIGHT PERIOD AT LESS THAN 10 KTS.
MOSTLY LIGHT AND VARIABLE WINDS CAN BE EXPECTED THROUGHOUT THE DAY
TUESDAY, WITH KIPL SHIFTING OUT OF THE WEST DURING THE EVENING HOURS.
FIRE WEATHER
THUNDERSTORM CHANCES WILL DWINDLE THE REMAINDER OF THE WEEK WITH
ONLY SLIGHT CHANCES REMAINING OVER HIGH TERRAIN AREAS OF FAR EASTERN
DISTRICTS. INSTEAD, TEMPERATURES WILL WARM SIGNIFICANTLY WITH MUCH
ABOVE NORMAL READINGS AND EXTREME HEAT WARNINGS. DESPITE THE WARMER,
DRIER CONDITIONS, HUMIDITY LEVELS WILL NOT FALL SUBSTANTIALLY WITH
MINIMUM AFTERNOON READINGS 15-30% THE NEXT COUPLE DAYS FALLING
CLOSER TO A 10-25% RANGE OVER THE WEEKEND. CORRESPONDINGLY,
OVERNIGHT RECOVERY WILL MOSTLY STAY IN A FAIR TO GOOD RANGE OF 30-
60%. WINDS SHOULD BE FAIRLY LIGHT THROUGH THE PERIOD WITH ONLY LOCAL
AFTERNOON GUSTS 20-25 MPH.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...EXTREME HEAT WARNING FROM 10 AM TODAY TO 8 PM MST MONDAY FOR
AZZ530-532.
EXTREME HEAT WARNING FROM 10 AM THURSDAY TO 8 PM MST MONDAY FOR
AZZ531-533>555-559.
CA...EXTREME HEAT WARNING FROM 10 AM TODAY TO 8 PM PDT MONDAY FOR
CAZ562>570.
EXTREME HEAT WARNING FROM 10 AM THURSDAY TO 8 PM PDT MONDAY FOR
CAZ560-561.
SHORT TERM...18
LONG TERM...18
AVIATION...LOJERO
FIRE WEATHER...18
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