951
FXUS65 KPSR 270520
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1020 PM MST FRI JUN 26 2026
UPDATE
06Z AVIATION DISCUSSION
KEY MESSAGES
- TEMPERATURES WILL COOL TREND THROUGH THE WEEKEND REACHING BELOW
NORMAL LEVELS FOR SEVERAL DAYS EARLY NEXT WEEK.
- UNUSUALLY STRONG WINDS WILL IMPACT THE REGION THROUGH SUNDAY
RESULTING IN AREAS OF BLOWING DUST AND CRITICAL FIRE WEATHER
CONDITIONS.
- MORE TRANQUIL WEATHER CONDITIONS AND A SLOW WARMING TREND WILL
ARRIVE DURING THE MIDDLE OF NEXT WEEK.
SHORT TERM /TODAY THROUGH SUNDAY/
SEASONALLY STRONG MIDLEVEL HEIGHT FALLS WERE SURGING INTO THE
WESTERN CONUS EARLY THIS AFTERNOON AS INCREASING DEEP SW FLOW
QUICKLY SCOURS AWAY BOUNDARY MOISTURE ACROSS THE FORECAST AREA.
DESPITE THIS LOSS OF LOW LEVEL MOISTURE, A SHEARED SHORTWAVE WITH
THE LAST VESTIGES OF MID/UPPER MOISTURE WAS LIFTING INTO NORTHERN
ARIZONA RESULTING IN VIRGA/LIGHT SHOWERS EXITING THE REGION. WHILE
THE LEAD SHORTWAVE CARVING OUT TROUGHING OVER THE PACIFIC NW IS
ALREADY EJECTING EASTWARD, UPSTREAM ENERGY WILL CONTINUE DIVE
SOUTHEAST INTENSIFYING AND AMPLIFYING TROUGHING OVER THE GREAT BASIN
SUCH THAT NEGATIVE HEIGHT ANOMALIES NEARLY 4 NORMALIZED STANDARD
DEVIATIONS BELOW NORMAL WILL BECOME ESTABLISHED THIS WEEKEND. WITH
H5 HEIGHTS LOCALLY RETREATING AS LOW AS A 582-585DM RANGE, FORECAST
CONFIDENCE IS EXCELLENT THAT TEMPERATURE WILL FALL 5F-10F BELOW
NORMAL HEADING INTO THE FIRST PART OF NEXT WEEK.
THE GREATEST IMPACT FROM THIS VERY UNUSUAL LATE JUNE SYSTEM WILL BE
A PROLONGED STRETCH OF GUSTY WINDS THROUGH THE WEEKEND. THE DEPTH OF
THE TROUGHING AND MAGNITUDE OF HEIGHT FALLS ENTERING THE REGION WILL
PROMOTE ENHANCED JET WINDS READILY MIXED THROUGH THE BOUNDARY LAYER.
U-WIND ANOMALIES AS MEASURED BY AN ENSEMBLE MEAN ARE NEAR SEASONAL
MAXIMUMS WITH ECMWF EFI OUTPUT SUGGESTING GUSTS VERY NEAR ALL-TIME
HIGHS BY LATE JUNE STANDARDS. IN TERMS OF RAW DATA, 30-40KT SPEEDS
FREQUENTLY WITHIN THE SFC-H7 LAYER WILL BE TAPPED DURING DAYTIME
MECHANICAL MIXING, AND FURTHER AIDED BY MOUNTAIN WAVE ACTIVITY
AROUND LARGER TERRAIN FEATURES. WIND ADVISORIES CONTINUE ALONG THE
CORRIDOR OF STRONGEST WINDS ALOFT, IN ADDITION TO THE TYPICAL WIND
PRONE AREAS WHERE DIFFICULT TRAVEL FOR HIGH PROFILE VEHICLES AND
LOCALIZED DENSE BLOWING DUST MAY BE COMMON. OTHERWISE, THE
COMBINATIONS OF THESE ENHANCED WIND GUSTS, LOW HUMIDITY LEVELS, AND
VERY DRY FUELS RECEPTIVE TO FIRE COULD RESULT IN EXTREME FIRE
BEHAVIOR AND UNCONTROLLED WILDFIRE GROWTH RESULTING IN HIGHLY
ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS.
LONG TERM /MONDAY THROUGH FRIDAY/
THE LARGE PACIFIC TROUGH THAT WILL BEGIN TO PUSH INLAND OVER THE
WEEKEND WILL REMAIN OVER THE WESTERN CONUS THROUGH MUCH OF NEXT
WEEK. WITH NEGATIVE HEIGHT ANOMALIES REMAINING IN PLACE,
TEMPERATURES WILL REMAIN A FEW DEGREES BELOW NORMAL THROUGH MIDWEEK,
WITH LOWER ELEVATION HIGHS IN THE UPPER 90S TO LOWER 100S. NBM
GUIDANCE SHOWS VERY LITTLE SPREAD BETWEEN THE 25TH AND 75TH
PERCENTILE WITH RESPECT TO HIGH TEMPERATURES BEFORE ENSEMBLES SHOWS
THE TROUGHING FEATURE BEGINNING TO BE DISPLACE BY THE SUBTROPICAL
HIGH TRYING AGAIN TO BUILD OVER THE DESERT SW. AS THE HIGH BEGINS TO
BUILD BACK OVER THE REGION, TEMPERATURES WILL BEGIN TO WARM BACK
TOWARDS NORMAL (GENERALLY 105F TO 110F). OTHERWISE, WHILE THE WIND
ADVISORIES WILL EXPIRE BY THE END OF THE WEEKEND, BREEZY CONDITIONS
ARE LIKELY TO PERSIST INTO EARLY NEXT WEEK.
AVIATION
UPDATED AT 0520Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
THE MAIN AVIATION CONCERN WILL CONTINUE TO BE BREEZY AFTERNOON
CONDITIONS WITH GUSTS UPWARDS OF 25 KT. WINDS SHOULD FOLLOW
FAMILIAR DIURNAL TRENDS THROUGH THE PERIOD, THOUGH CONFIDENCE
REGARDING A PREVAILING DIRECTION AT KPHX THROUGH MUCH OF THE NIGHT
IS LOW, THEREFORE, ELECTED TO INCLUDE A VRB GROUP IN THE NEAR TERM
TO REFLECT THIS UNCERTAINTY. OVERNIGHT AMENDMENTS MAY BE NEEDED IF
CONFIDENCE INCREASES. OTHER THAN A FEW DISTANT HIGH CLOUDS, SKIES
SHOULD BE MOSTLY CLEAR.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
BREEZY TO WINDY CONDITIONS WILL CONTINUE TO BE THE MAIN AVIATION
CONCERN THROUGH THE NEXT 24 HOURS. OUTSIDE OF CALMER WINDS
OVERNIGHT, GUSTS 25-35 KT, WITH OCCASIONALLY HIGHER GUSTS NEAR 40
KT, WILL BE COMMON SATURDAY AFTERNOON AND EVENING. SLANTWISE AND
SURFACE VIS IMPACTS DUE TO WIND GENERATED BLDU APPEAR TO BE
POSSIBLE, THOUGH THE EXACT TIMING IS UNCERTAIN. A TEMPO GROUP HAS
BEEN ADDED AT KBLH BETWEEN 23-03Z TO AT LEAST INDICATE THE
POTENTIAL FOR IMPACTS. TIMING OF THIS TEMPO MAY NEED TO BE
ADJUSTED, OR EVEN UPGRADED TO A PREVAILING LINE IF PERSISTENT SUB-
VFR CONDITIONS ARE OBSERVED. DUE TO THE ORIENTATION OF THE WIND,
KIPL IS NOT LIKELY TO SEE DUST IMPACTS, BUT A FEW OBS OF MVFR VIS
CANNOT BE RULED OUT. OTHER THAN SOME PASSING HIGH CLOUDS, SKIES
WILL BE MOSTLY CLEAR DURING THE FORECAST PERIOD.
FIRE WEATHER
ELEVATED TO CRITICAL FIRE DANGER WILL CONTINUE TODAY DUE TO LOW
HUMIDITY, VERY WARM TEMPERATURES, AND AFTERNOON UPSLOPE/UPVALLEY
BREEZY CONDITIONS. RED FLAG WARNINGS HAVE BEEN ISSUED TODAY THROUGH
SUNDAY FOR MUCH OF THE AREA. EXPECT MINRHS CLOSER TO 5-15% STARTING
TODAY, THEN STAYING IN THIS RANGE FOR SEVERAL DAYS. WINDS WILL
INCREASE THIS EVENING WITH GUSTS INTO A 20-35 MPH RANGE AND LOCALLY
HIGHER OVER HIGHER TERRAIN AREAS. WINDS ARE LIKELY TO PEAK ON
SATURDAY WITH GUSTS COMMONLY REACHING 25-40 MPH. THESE WINDY AND DRY
CONDITIONS WILL COMBINE WITH THE VERY DRY FUELS TO CREATE A RISK OF
EXTREME FIRE BEHAVIOR. TEMPERATURES WILL COOL THIS WEEKEND REACHING
SLIGHTLY BELOW NORMAL LEVELS STARTING SUNDAY. WINDS ARE EXPECTED TO
GRADUALLY DIMINISH NEXT MONDAY INTO TUESDAY.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...RED FLAG WARNING UNTIL 8 PM MST SATURDAY FOR AZZ131.
WIND ADVISORY FROM 11 AM TO 11 PM MST SATURDAY FOR AZZ530-533.
RED FLAG WARNING UNTIL 8 PM MST SUNDAY FOR AZZ133.
CA...RED FLAG WARNING UNTIL 8 PM PDT SATURDAY FOR CAZ231.
WIND ADVISORY FROM 11 AM TO 11 PM PDT SATURDAY FOR CAZ564>567-
569-570.
WIND ADVISORY UNTIL 11 AM PDT SUNDAY FOR CAZ562.
SHORT TERM...18
LONG TERM...RYAN
AVIATION...RW
FIRE WEATHER...RYAN/KUHLMAN
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