149
FXUS65 KPSR 220505
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1005 PM MST THU MAY 21 2026
UPDATE
UPDATED 06Z AVIATION DISCUSSION.
KEY MESSAGES
- TEMPERATURES WILL GRADUALLY WARM THROUGH THE WEEKEND WITH LOWER
DESERT HIGHS REACHING THE UPPER 90S TO NEAR 100 DEGREES
FOLLOWING COMFORTABLE MORNING READINGS.
- DRY CONDITIONS WILL PREVAIL THROUGH EARLY NEXT WEEK WITH
TYPICAL AFTERNOON BREEZINESS.
- A SLIGHT CHANCE OF THUNDERSTORMS WILL EXIST OVER THE EASTERN
ARIZONA HIGH TERRAIN EARLY NEXT WEEK, ALBEIT WITH LIMITED
RAINFALL POTENTIAL.
SHORT TERM /TODAY THROUGH FRIDAY/
EARLY AFTERNOON 500MB ANALYSIS REVEALS BROAD TROUGHING CONTINUING TO
SIT OVER THE DESERT SOUTHWEST, WHILE A MORE POTENT DISTURBANCE
PROVIDES SOME LATE SEASON SNOW TO PARTS OF WYOMING AND MONTANA.
UNLIKE OUR NORTHERN NEIGHBORS, THE WEAK TROUGHING OVER OUR FORECAST
AREA LACKS MOISTURE AND ENERGY, SO DRY AND TRANQUIL CONDITIONS
WILL CONTINUE THROUGH THE END OF THE WORK WEEK. THE NEGATIVE
HEIGHT ANOMALIES ASSOCIATED WITH THIS PATTERN HAS HELPED KEEP
TEMPERATURES AT OR BELOW NORMAL SINCE THE BEGINNING OF THIS WEEK,
AND EVEN THOUGH WE HAVE SEEN READINGS CLIMB OVER THE PAST FEW
DAYS, NO SIGNIFICANT WARMUP IS EXPECTED SO AFTERNOON HIGHS TODAY
AND FRIDAY WILL REMAIN RIGHT AROUND NORMAL. LOWER DESERT HIGHS
WILL RANGE IN THE MIDDLE TO UPPER 90S, WHILE HIGHER ELEVATION
LOCATIONS WILL SEE VALUES MORE IN THE 70S AND 80S. NO WEATHER
RELATED TRAVEL IMPACTS ARE ANTICIPATED IF YOU ARE PLANNING TO
START THIS MEMORIAL DAY WEEKEND A LITTLE EARLY.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
OVER THE WEEKEND, LOW AMPLITUDE SHORTWAVE RIDGING WILL
TEMPORARILY BUILD INTO THE SW CONUS IN RESPONSE TO DEEPENING
TROUGHING ENTERING THE EASTERN PACIFIC. THE FULL NAEFS SUITE
CONTINUES TO EXHIBIT MINIMAL SPREAD IN THE H5 HEIGHT PATTERN WITH
A 582-585DM LEVELS SETTLING OVER THE CWA. AS SUCH, CONFIDENCE IS
VERY GOOD THAT TEMPERATURES WILL WARM SEVERAL MORE DEGREES INTO A
SLIGHTLY ABOVE NORMAL RANGE, BUT CERTAINLY NOTHING PARTICULARLY
UNUSUAL FOR THIS TIME OF YEAR. EARLY NEXT WEEK, THE RIDGE AXIS
SHIFTS EAST INTO NEW MEXICO WITH A STRONG SUBTROPICAL JET PUNCHING
INTO NORTHERN MEXICO. THE RESULTING FLOW PATTERN WILL BECOME
DEEPLY MERIDIONAL ALLOWING THE IMPORT OF MARGINALLY BETTER
MOISTURE PROFILES, ALTHOUGH LIKELY NO MORE THAN 5 G/KG WITHIN THE
BOUNDARY LAYER.
THIS TYPE OF TRANSITION SEASON PATTERN IS NOT UNCOMMON FOR THE SW
CONUS (ESPECIALLY DURING DEVELOPING EL NINO EPISODES - E.G. 2023
AND 2015), HOWEVER THE INTENSITY OF THIS SHORTWAVE AND ASSOCIATED
SUBTROPICAL JET ARE UNUSUALLY STRONG. GENERAL PATTERN RECOGNITION
CONTINUES TO SUGGEST ROBUST JET FORCED ASCENT AND COOLING ALOFT
SURGING INTO SOUTH-CENTRAL ARIZONA EARLY NEXT WEEK. ENSEMBLE
MEMBERSHIP INDICATES SOME MINOR UNCERTAINTY IN TIMING, INTENSITY,
AND MOISTURE AVAILABILITY, THOUGH THE OVERWHELMING PREPONDERANCE
OF MODEL OUTPUT HIGHLIGHTS MONDAY AFTERNOON AND EVENING AS THE
MOST OPPORTUNE TIME FRAME WHERE DEEP MOUNTAIN CONVECTION OVER THE
EASTERN CWA WOULD BE SUPPORTED. GIVEN THE LIKELY THERMODYNAMIC
PROFILES, MINIMAL ACTUAL RAINFALL MAY BE COMMON WITH THIS
CONVECTION, BUT RATHER NUMEROUS DRY LIGHTNING STRIKES AND GUSTY
OUTFLOW WINDS WOULD BE THE MORE LIKELY OUTCOME. SHOULD THIS
EVOLUTION COME TO FRUITION, THE GREATEST CONCERN WOULD BE WILDFIRE
STARTS IN REMOTE HIGH TERRAIN AREAS. THE PASSAGE OF STRONGER
TROUGHING NORTH OF THE FORECAST AREA MIDWEEK COULD HELP INCREASE
WINDS WHICH COULD EXACERBATE FIRE WEATHER ISSUES, THOUGH LARGER
ENSEMBLE SPREAD YIELDS LOWER FORECAST CONFIDENCE DURING THIS TIME
FRAME AT THE END OF THE FORECAST PERIOD.
AVIATION
UPDATED AT 0505Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO AVIATION WEATHER CONCERNS WILL EXIST THROUGH THE TAF PERIOD
UNDER MOSTLY CLEAR SKIES. WINDS WILL GENERALLY FOLLOW THEIR
TYPICAL DIURNAL TENDENCIES WITH SPEEDS AOB 10 KT.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO AVIATION CONCERNS ARE EXPECTED DURING THE NEXT 24 HOURS UNDER
MOSTLY CLEAR SKIES. AT KIPL, CURRENT SW'RLY WINDS WILL GO SE
AROUND SUNRISE TOMORROW MORNING WITH WIND SPEEDS STAYING AOB 10 KT
THROUGH THE PERIOD. AT KBLH, CURRENT SW'RLY WINDS WILL GO
SOUTHERLY DURING THE OVERNIGHT PERIOD. WIND SPEEDS WILL REMAIN AOB
10 KT THROUGH TOMORROW MORNING WITH SPEEDS INCREASING DURING THE
AFTERNOON AND EVENING HOURS, WITH SOME OCCASIONAL GUSTS INTO THE
UPPER TEENS.
FIRE WEATHER
TEMPERATURES WILL REMAIN IN A SLIGHTLY ABOVE NORMAL CATEGORY
THROUGH EARLY NEXT WEEK WITH DRY CONDITIONS OVER THE MAJORITY OF
THE DISTRICTS. MINIMUM AFTERNOON HUMIDITY LEVELS WILL FALL INTO A
5-15% RANGE THIS WEEK WITH A MODEST INCREASE IN MOISTURE RESULTING
IN LEVELS INCREASING CLOSER TO 10-20% OVER THE WEEKEND. THIS
MOISTURE INCREASE ALONG WITH AN INCOMING WEATHER DISTURBANCE MAY
LEAD TO A SLIGHT CHANCE FOR AFTERNOON/EVENING STORMS AND LIGHTNING
STRIKES OVER HIGH TERRAIN OF EASTERN DISTRICTS. LITTLE TO NO
RAINFALL WOULD BE EXPECTED WITH THIS ACTIVITY RESULTING IN A
HEIGHTENED THREAT FOR NEW WILDFIRE STARTS, PARTICULARLY MONDAY
AFTERNOON. POOR TO FAIR OVERNIGHT RECOVERY OF 20-40% WILL ONLY
IMPROVE SLIGHTLY OVER THE WEEKEND. TYPICAL AFTERNOON SPRING
UPSLOPE GUSTINESS OF 15-25 MPH WILL BE COMMON THROUGH THE PERIOD
WITH THE MOST PRONOUNCED GUSTS OVER EASTERN DISTRICT HIGH TERRAIN
AND THROUGH THE LOWER COLORADO RIVER VALLEY.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...RW
LONG TERM...18
AVIATION...BERISLAVICH
FIRE WEATHER...18
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