447
FXUS65 KPSR 231705
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1005 AM MST SAT MAY 23 2026
UPDATE
UPDATED AVIATION DISCUSSION
KEY MESSAGES
- SLIGHTLY ABOVE NORMAL TEMPERATURES THROUGH EARLY NEXT WILL COOL TO
NEAR OR SLIGHTLY BELOW NORMAL LEVELS DURING THE MIDDLE OF THE WEEK.
- DRY CONDITIONS WITH TYPICAL AFTERNOON BREEZINESS WILL PREVAIL
THROUGH THE BEGINNING OF NEXT WEEK WITH WIND SPEEDS INCREASING
DURING THE MIDDLE OF THE WEEK.
- A SLIGHT CHANCE OF THUNDERSTORMS WILL EXIST OVER THE EASTERN
ARIZONA HIGH TERRAIN MONDAY, ALBEIT WITH LIMITED RAINFALL POTENTIAL.
SHORT TERM /TODAY THROUGH MONDAY/
EARLY MORNING OBJECTIVE ANALYSIS DEPICTS REMNANT WEAK TROUGHING OVER
NORTHERN MEXICO, HOWEVER AN ENHANCED SUBTROPICAL JET AND APPROACHING
UPSTREAM EAST PACIFIC ENERGY WILL DISPLACE THIS FEATURE INTO THE
SOUTHERN PLAINS OVER THE NEXT 24 HOURS. IN ITS PLACE, TRANSIENT
SHORTWAVE RIDGING WILL BUILD INTO THE SW CONUS WITH H5 HEIGHTS
INCREASING INTO A 580-584DM RANGE THROUGH THE WEEKEND WHILE ALSO
FORCING DEEP SOUTHERLY FLOW ON THE WESTERN PERIPHERY OF THE ANTI-
CYCLONE. AS ENSEMBLE NUMERICAL SPREAD REMAINS VERY NARROW, FORECAST
CONFIDENCE IS EXCELLENT SHOWING DRY CONDITIONS AND TEMPERATURES 2F-
4F ABOVE NORMAL WITH THE WARMEST LOWER DESERT LOCATIONS JUST
BREACHING THE 100F THRESHOLD.
THE AFOREMENTIONED SOUTHERLY FLOW WILL BRIEFLY IMPORT MARGINALLY
BETTER MOISTURE INTO SOUTHERN AND EASTERN ARIZONA, THOUGH WITH
MIXING RATIOS NO MORE THAN ABOUT 5-6 G/KG, AND ONLY A NARROW DEPTH
OF POTENTIAL SATURATION ABOVE THE H7 LAYER. HOWEVER, THE FORECAST
AREA WILL ALIGN NEARLY PERFECTLY IN THE LEFT FRONT JET QUADRANT WITH
IMPRESSIVE DIVERGENCE AND STRONG ASCENT. THIS PATTERN OF INCOMING
COOLING ALOFT AND STEEPENING LAPSE RATES JUXTAPOSED WITH A NARROW
PLUME OF SATURATED LIFT SUGGESTS SCATTERED SHOWERS AND A FEW STORMS
DURING THE DAY MONDAY OVER HIGHER TERRAIN EAST OF PHOENIX. LIMITED
INSTABILITY WITH LARGE T/TD SPREADS AND A DRY SUB-CLOUD LAYER WOULD
FAVOR DRY LIGHTNING STRIKES AND GUSTY OUTFLOW WINDS VERSUS
ACCUMULATING RAINFALL. HAVE CUT NBM POPS MODESTLY AS THEY APPEAR A
BIT AGGRESSIVE GIVEN THE THERMODYNAMIC PROFILES AND PRESENCE OF
ENHANCED EVAPORATION EVEN OVER MOUNTAINOUS AREAS.
LONG TERM /TUESDAY THROUGH FRIDAY/
AN OVERWHELMING PREPONDERANCE OF ENSEMBLE MEMBERS ARE NOW
ADVERTISING A WESTERN CONUS PATTERN PREVIOUSLY PREFERRED BY HUMAN
FORECASTERS WITH DEVELOPING BLOCKING, AND DEEPENING SLOW MOVING
FEATURES AFFECTING THE WESTERN CONUS. AS A RESULT, CONFIDENCE HAS
IMPROVED THAT PRONOUNCED NEGATIVE HEIGHT ANOMALIES ENTERING THE
PACIFIC NW WILL DESCEND INTO THE GREAT BASIN, THEN STALL IN THE FORM
OF A LARGE CUTOFF LOW, PERHAPS AS FAR SOUTH AS SOUTHERN UT/NORTHERN
AZ. GIVEN THIS EVOLUTION, TEMPERATURES WILL RETREAT INTO A BELOW
NORMAL CATEGORY DURING THE MIDDLE OF THE WEEK, AND POSSIBLY
PERSISTING THROUGH THE REMAINDER OF THE WEEK. AUTOMATED NBM/WPC
OUTPUT HAS STARTED REFLECTING THIS TREND, THOUGH IT WOULD NOT BE
UNEXPECTED THAT FUTURE FORECASTS TRIM A COUPLE MORE DEGREES CLOSER
TO THE LOWER QUARTILE OF THE NUMERICAL DISTRIBUTION DURING THE
LATTER HALF OF THE WEEK.
OTHERWISE, THE GREATEST IMPACT WITH THIS SYSTEM SHOULD BE INCREASED
WIND SPEEDS WITH A SEASONALLY STRONG JET AND AGGRESSIVE HEIGHT FALLS
ENTERING THE REGION. THE INITIAL SURGE WILL ENTER SE CALIFORNIA LATE
TUESDAY, THEN SWEEP ACROSS THE ENTIRE CWA ON WEDNESDAY. DEEP
MECHANICAL MIXING SHOULD TAP HIGHER MOMENTUM 20-30KT WINDS THROUGH
THE BOUNDARY LAYER WITH THE MOST INTENSE SPEEDS IN DOWNSLOPING
REGIONS OF SE CALIFORNIA AND AROUND TERRAIN FEATURES OF THE EASTERN
CWA. RECENT MANDATED NBM FORECASTS HAVE STARTED CATCHING UP ON THIS
INCREASED WIND SPEED PARADIGM, HOWEVER SOME OF THE DEFICIENCIES IN
THE ENSEMBLING PROCESS ARE LIKELY STILL RESTRICTING THE FULL EXTENT
OF WIND SPEEDS. REGARDLESS, ADVISORIES IN THE MOST WIND PRONE AREAS
OF SE CALIFORNIA ARE LOOKING MORE LIKELY, WHILE LOW RELATIVE
HUMIDITY AND DRY FUELS MAY FOSTER AN ENHANCED FIRE DANGER ACROSS
MUCH OF THE REGION. DEPENDING ON THE POSITIONING AND PROGRESSION OF
THE ATTENDANT CLOSED LOW, THESE IMPACTS MAY PERSIST INTO THURSDAY
BEFORE RELAXING LATE IN THE WEEK.
AVIATION
UPDATED AT 1705Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO MAJOR AVIATION CONCERNS WILL EXIST DURING THE TAF PERIOD. WINDS
WILL FOLLOW FAMILIAR DIURNAL TRENDS WITH SOME OCCASIONAL
BREEZINESS DURING THE AFTERNOON AND EVENING. OTHER THAN FEW
DISTANT MID-LEVEL CU, SKIES WILL BE MOSTLY CLEAR OVER METRO
TERMINALS.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR AVIATION CONCERNS ARE EXPECTED DURING THE NEXT 24 HOURS.
WINDS WILL FAVOR GENERALLY A S'LRY COMPONENT AT BOTH TERMINALS,
WITH SOME ELEVATED SUSTAINED SPEEDS AND OCCASIONAL GUSTS THIS
AFTERNOON AND EARLY EVENING IN THE UPPER-TEENS TO AROUND 20 KT.
SKIES WILL BE MOSTLY CLEAR THROUGH SUNDAY MORNING.
FIRE WEATHER
TEMPERATURES WILL REMAIN IN A SLIGHTLY ABOVE NORMAL CATEGORY THROUGH
EARLY NEXT WEEK BEFORE MODEST COOLING ARRIVES DURING THE MIDDLE OF
THE WEEK. MINIMUM AFTERNOON HUMIDITY LEVELS WILL FALL INTO A 10-20%
RANGE WITH POOR TO FAIR OVERNIGHT RECOVERY OF 20-40% IMPROVING
CLOSER TO A FAIR TO GOOD RANGE NEXT WEEK. A MARGINAL INCREASE IN
MOISTURE WILL RESULT IN A SLIGHT CHANCE FOR AFTERNOON THUNDERSTORMS
AND A FEW LIGHTNING STRIKES OVER HIGH TERRAIN OF EASTERN DISTRICTS
MONDAY. LITTLE TO NO ACCUMULATING RAINFALL SHOULD BE ANTICIPATED,
AND THE THREAT FOR NEW WILDFIRE STARTS DUE TO LIGHTNING STRIKES WILL
BE HEIGHTENED. TYPICAL AFTERNOON UPSLOPE GUSTINESS OF 15-25 MPH WILL
BE COMMON THROUGH EARLY NEXT WEEK WITH SPEEDS INCREASING MARKEDLY
DURING THE MIDDLE OF THE WEEK. STRONGER GUSTS OVER EASTERN DISTRICT
HIGH TERRAIN AND THROUGH THE LOWER COLORADO RIVER VALLEY WEDNESDAY
COMBINED WITH LOW RH AND DRY FUELS MAY RESULT IN NEAR CRITICAL
CONDITIONS.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...18
LONG TERM...18
AVIATION...RW
FIRE WEATHER...18
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