077
FXUS65 KPSR 151122
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
422 AM MST THU MAY 15 2025
UPDATE
UPDATED 12Z AVIATION DISCUSSION
KEY MESSAGES
1) NEAR TO BELOW NORMAL TEMPERATURES THROUGH THE BEGINNING OF
NEXT WEEK
2) GUSTY WINDS OVER THE WEEKEND RESULTING IN A LOCALLY ELEVATED
FIRE DANGER
3) MEDIUM TO HIGH POTENTIAL FOR HOT TEMPERATURES AND WIDESPREAD
MODERATE HEATRISK RETURNING LATE NEXT WEEK
DISCUSSION
WEATHER PATTERN OVERVIEW:
THE SHORTWAVE TROUGH THAT EXITED THE REGION YESTERDAY IS NOW
MOVING INTO THE NORTHERN PLAINS, BUT LARGE SCALE TROUGHING REMAINS
IN PLACE OVER THE BULK OF THE WESTERN U.S., INCLUDING OUR REGION.
THIS PATTERN WILL REMAIN IN PLACE FOR TODAY AND FRIDAY, BUT WE
WILL SEE SOME MODEST HEIGHT RISES ALOFT AND SOME WARMING BRINGING
OUR DAYTIME HIGHS UP TO AROUND 90 DEGREES TODAY AND INTO THE LOWER
90S TO UP TO 95 DEGREES ON FRIDAY.
THIS TRANQUIL WEATHER WILL BEGIN TO CHANGE BY SATURDAY AS A FAST
MOVING SHORTWAVE TROUGH DIVES SOUTH SOUTHEASTWARD THROUGH
CALIFORNIA BRINGING INCREASING HEIGHT FALLS ACROSS MUCH OF THE
DESERT SOUTHWEST. AS A RESULT, WINDS WILL BECOME BREEZY TO LOCALLY
WINDY BY EARLY AFTERNOON SATURDAY, ESPECIALLY ACROSS THE WESTERN
DESERTS WHERE ADVISORY LEVEL WINDS MAY BECOME POSSIBLE. WINDS
ACROSS SOUTHERN AND CENTRAL ARIZONA WILL ALSO BECOME BREEZY BY MID
TO LATE AFTERNOON WITH GUSTS MAINLY BETWEEN 20-30 MPH. THESE
GUSTY WINDS AND LOW RHS DOWN TO 10% SATURDAY AFTERNOON/EARLY
EVENING ARE LIKELY TO RESULT IN ELEVATED FIRE WEATHER CONDITIONS.
ENSEMBLE GUIDANCE SHOWS VERY GOOD AGREEMENT SHOWING THE TRACK OF
THIS INITIAL SHORTWAVE ACROSS NORTHERN ARIZONA SATURDAY NIGHT INTO
SUNDAY BEFORE A SECONDARY SHORTWAVE IS LIKELY TO FOLLOW A FAIRLY
SIMILAR TRACK ACROSS THE GREAT BASIN INTO NORTHERN ARIZONA LATE
SUNDAY INTO MONDAY. BOTH OF THESE DISTURBANCES WILL BE QUITE
MOISTURE STARVED, BUT GUIDANCE SHOWS THE SECOND ONE ADVECTING IN A
BIT MORE MOISTURE OFF THE PACIFIC PUSHING LOW LEVEL MIXING RATIOS
CLOSER TO 5 G/KG AND SURFACE DEW POINTS INTO THE 40S. NBM POPS DO
SHOW SOME 10-20% CHANCES FOR SHOWERS AS FAR SOUTH AS THE HIGHER
TERRAIN EAST OF PHOENIX DURING THE DAYTIME MONDAY WITH THE BEST
CHANCES OVER NORTHEAST ARIZONA.
WINDS ON SUNDAY ARE ALSO EXPECTED TO BE BREEZY TO LOCALLY WINDY,
ESPECIALLY ACROSS SOUTHEAST CALIFORNIA AND THE ARIZONA HIGHER
TERRAIN, WHILE TEMPERATURES TAKE A DIP WITH HIGHS FALLING BACK TO
BETWEEN 80-85 DEGREES. AS THE SECOND SHORTWAVE MOVES THROUGH
NORTHERN PORTIONS OF OUR REGION ON MONDAY, WINDS WILL AGAIN BE
BREEZY BUT LIKELY TO A LESSER DEGREE COMPARED TO THE WEEKEND.
TEMPERATURES WILL ALSO BEGIN TO WARM UP ACROSS THE WESTERN DESERTS
BEGINNING MONDAY WITH HIGHS APPROACHING THE 90 DEGREE MARK.
UPPER LEVEL RIDGING IS EXPECTED TO QUICKLY SPREAD OVER THE REGION
BY NEXT TUESDAY INTO WEDNESDAY WITH ENSEMBLES HEAVILY FAVORING
FURTHER STRENGTHENING LATE NEXT WEEK. TEMPERATURES WILL BE QUICK
TO RESPOND TO THE INCREASING HEIGHTS ALOFT WITH HIGHS WARMING
TO AROUND 100 DEGREES BY WEDNESDAY AND LIKELY ECLIPSING 105
DEGREES AT SOME POINT LATE NEXT WEEK INTO NEXT WEEKEND. THE NBM IS
ALSO SHOWING AROUND A 10% PROBABILITY OF REACHING 110 DEGREES
ACROSS THE TYPICAL HOTTER LOWER DESERTS NEXT FRIDAY AND SATURDAY.
GIVEN THE GOOD ENSEMBLE AGREEMENT, WE ARE QUITE LIKELY TO SEE
WIDESPREAD MODERATE HEATRISK FOR AT LEAST THE FIRST PART OF THE
MEMORIAL DAY WEEKEND.
FORECAST CONFIDENCE & DEVIATIONS:
MODEL GUIDANCE IS IN VERY GOOD AGREEMENT THROUGH AT LEAST THE
COMING WEEKEND PROVIDING LITTLE EXPECTED CHANGES IN THE FORECAST
OVER THE NEXT FEW DAYS. THE WIND FORECAST VERY WELL COULD INCREASE
MARGINALLY OVER THE WEEKEND, BUT NOT LIKELY BY MORE THAN 20-30%.
MODEL SPREAD FOR NEXT WEEK IS HIGHER, ESPECIALLY TOWARD NEXT
WEEKEND, BUT OVERALL IT IS STILL GOOD GIVING US MEDIUM TO HIGH
FORECAST CONFIDENCE IN MODERATE HEATRISK DEVELOPING BY AROUND NEXT
THURSDAY. OVERALL THIS FORECAST PACKAGE HAD NO APPRECIABLE
DEVIATION FROM THE MANDATED NBM INITIALIZATION.
AVIATION
UPDATED AT 120Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, KDVT:
WINDS WILL FOLLOW THEIR TYPICAL DIURNAL TENDENCIES THROUGH THE TAF
PERIOD. LIGHT EASTERLY WINDS, WITH PERIODS OF CALM WINDS, WILL
CONTINUE THROUGH MOST OF THE MORNING. WINDS WILL THEN BECOME
WESTERLY BY LATE THIS MORNING/EARLY THIS AFTERNOON WITH SPEEDS
GENERALLY AOB 8 KT. SOME OCCASIONAL GUSTS INTO THE MID-TEENS WILL
BE POSSIBLE THIS AFTERNOON. WINDS WILL THEN GO BACK EASTERLY LATE
TONIGHT/DURING THE OVERNIGHT HOURS, WITH SPEEDS AOB 5 KT WITH
PERIODS OF LIGHT AND VARIABLE TO CALM WINDS. SKIES WILL BE MOSTLY
CLEAR.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
CURRENT LIGHT WESTERLY WINDS WILL GO LIGHT AND VARIABLE AROUND 14Z
AT KIPL, THEN BECOME SOUTHEASTERLY THIS AFTERNOON, THEN BACK
WESTERLY THIS EVENING. AT KBLH, CURRENT LIGHT AND VARIABLE WINDS
WILL DEVELOP A SOUTHERLY/SOUTHWESTERLY COMPONENT THIS AFTERNOON
FOR THE REMAINDER OF THE TAF PERIOD. WIND SPEEDS AT BOTH TERMINALS
WILL GENERALLY BE AOB 7 KT. SKIES WILL BE MOSTLY CLEAR.
FIRE WEATHER
SEASONABLY DRY CONDITIONS, NEAR NORMAL TEMPERATURES, AND FAIRLY
LIGHT WINDS ARE EXPECTED THROUGH FRIDAY. DAILY MINRHS WILL HOVER
AROUND 10% WHILE OVERNIGHT RECOVERIES WILL BE FAIR TO POOR WITH
READINGS BETWEEN 20-30% OVER THE EASTERN DISTRICTS TO 30-45% OVER
THE WESTERN DISTRICTS. MORE UNSETTLED WEATHER IS EXPECTED FOR THE
COMING WEEKEND WITH INCREASED WINDS AND EVENTUALLY COOLER
TEMPERATURES STARTING SUNDAY. SATURDAY SHOULD ALSO BRING ELEVATED
FIRE WEATHER CONDITIONS ACROSS THE EASTERN ARIZONA HIGHER TERRAIN
WITH AFTERNOON RHS BETWEEN 10-15% AND WIND GUSTS OF 20-30 MPH.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
DISCUSSION...KUHLMAN
AVIATION...BERISLAVICH
FIRE WEATHER...KUHLMAN
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