179
FXUS65 KPSR 102109
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
209 PM MST SAT MAY 10 2025
SYNOPSIS
HOTTEST TEMPERATURES SO FAR THIS YEAR ARE EXPECTED TODAY AND
TOMORROW, WITH HIGHS ACROSS THE LOWER DESERT RANGING FROM 100-108.
THIS IS DUE TO HIGH PRESSURE ALOFT FULLY SETTLING OVER THE REGION.
WIDESPREAD MODERATE HEATRISK TO LOCALIZED MAJOR HEATRISK WILL
LAST THROUGH THE WEEKEND BECAUSE OF THESE TEMPERATURES. DAILY
BREEZY CONDITIONS HAVE DEVELOPED THIS MORNING AND WILL CONTINUE
INTO NEXT WEEK AS THE NEXT WEATHER SYSTEM MOVES INTO THE REGION.
ALTHOUGH THIS SYSTEM WILL BE DRY, TEMPERATURE WILL COOL AS IT
REACHES THE REGION.
DISCUSSION
UPPER LEVEL WV IMAGERY SHOWS RIDGING ALONG WITH DRY AIR ALOFT
OVER THE REGION. PEAK H5 HEIGHTS TODAY AND TOMORROW WILL GENERALLY
BE BETWEEN 584-586, CAUSING HIGH TEMPERATURES TO WARM TO 100-108
DEGREES ACROSS THE LOWER DESERT, AND UPPER 80S TO UPPER 90S IN
THE HIGHER TERRAINS. THESE TEMPERATURES HAVE RESULTED IN
WIDESPREAD MODERATE HEATRISK AND SOME MORE LOCALIZED MAJOR
HEATRISK FOR BOTH TODAY AND TOMORROW. SMART HEAT SAFETY OVER THE
WEEKEND WILL BE IMPORTANT SO LIMIT OUTDOOR TIME, WEAR SUNSCREEN,
WEAR LIGHT/LOOSE FITTING CLOTHING AND STAY HYDRATED. WHILE HIGH
TEMPERATURES TOMORROW ARE EXPECTED TO BE SIMILAR TO TODAY'S, AN
INCREASE IN CLOUD COVERAGE COULD KEEP SOME LOCATIONS FROM REACHING
THE CURRENT NBM FORECAST.
TODAY BREEZY CONDITIONS HAVE DEVELOPED OUT OF THE EAST/SOUTHEAST
AS THE PRESSURE GRADIENT TIGHTENED BETWEEN THE LOW PRESSURE OVER LOUISIANA
AND THE HIGH PRESSURE CENTERED OVERHEAD TODAY. WIND GUSTS TODAY
WILL BE DIMINISHING THROUGHOUT THE AFTERNOON/EVENING AS THE PEAK
GUSTS, 25-35 MPH, WERE MOSTLY THIS MORNING. TOMORROW A SIMILAR
WIND PATTERN WILL TAKE HOLD BUT SPEEDS WILL BE ROUGHLY 5 MPH
LOWER.
GLOBAL ENSEMBLES SHOW THE AFOREMENTIONED LOW PRESSURE, CURRENTLY IN
THE GULF OF ALASKA, MOVING ONSHORE IN THE PACIFIC NORTHWEST BY LATE
THIS WEEKEND/VERY EARLY NEXT WEEK. DURING THE EARLY APPROACH OF
THIS SYSTEM (MONDAY) TEMPERATURES IN THE LOWER DESERTS WILL EVER
SO SLIGHTLY COOL WITH FORECASTED AFTERNOON HIGHS IN THE HIGH 90S,
TO LOW 100S. AS THIS SYSTEM MOVES MORES FURTHER INTO WESTERN CONUS
(TUESDAY/WEDNESDAY), WE WILL SEE ADDITIONAL COOLING, WITH
WEDNESDAY FORECASTING HIGH TEMPERATURES IN THE MID TO HIGH 80S,
WHICH WILL BE BELOW NORMAL. HOWEVER ENSEMBLES AGREE THAT THE
CENTER OF THE LOW WILL STAY WELL TO OUR NORTH, RESULTING IN
OVERALL LACKLUSTER COOLING FOR THE REGION. GLOBAL ENSEMBLE MODELS
START TO DIFFER A LITTLE ON THE HOW LONG THE LOW WILL LINGER OVER
WESTERN CONUS. HOWEVER, MOST MEMBERS SHOW THE LOW WEAKENING, BUT
LINGERING ACROSS OUR REGION FOR THE LATTER HALF OF NEXT WEEK. THIS
WOULD ALLOW TEMPERATURES TO WARM TO NEAR NORMAL FOR THE END OF
NEXT WEEK.
AVIATION
UPDATED AT 1710Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, KDVT:
NO MAJOR WEATHER ISSUES WILL EXIST THROUGH SUNDAY AFTERNOON UNDER
CLEAR SKIES. CONFIDENCE IS VERY GOOD THAT EAST WINDS WILL PREVAIL
THROUGH THIS AFTERNOON AND EVENING WITHOUT THE TYPICAL WESTERLY
SWITCH. GUSTS NEAR 25KT EARLY IN THE AFTERNOON WILL ABATE BY LATE
AFTERNOON. A FEW EASTERLY GUSTS WILL BE POSSIBLE AGAIN MID/LATE
SUNDAY MORNING, HOWEVER LIKELY NOT NEARLY AS PRONOUNCED AS TODAY.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO SIGNIFICANT WEATHER ISSUES WILL EXIST THROUGH SUNDAY MORNING
UNDER PERIODS OF PASSING HIGH CIRRUS DECKS. WHILE AN E/SE COMPONENT
WILL PREVAIL THE MAJORITY OF THE PERIOD WITH A FEW STRONGER GUSTS, A
BRIEF N/NW DRAINAGE COMPONENT SHOULD DEVELOP DURING THE LATE
NIGHT/EARLY MORNING.
FIRE WEATHER
WITH HIGH PRESSURE FIRMLY OVERHEAD THIS WEEKEND, TEMPERATURES WILL
CLIMB INTO THE 100-108 DEGREE RANGE ACROSS THE LOWER DESERTS AND
MOST HIGHER ELEVATIONS WILL SEE HIGH TEMPERATURES RANGING FROM THE
UPPER 80S TO UPPER 90S. MINRHS WILL BE IN THE 7-15% RANGE THROUGH
MONDAY. BREEZY CONDITIONS HAVE DEVELOPED THIS MORNING ACROSS
SOUTHERN AND CENTRAL ARIZONA WITH GUSTS OF 25-35 MPH OUT OF THE
EAST/SOUTHEAST. SPEEDS WILL DECREASE A LITTLE THROUGHOUT THE
AFTERNOON/EVENING. A SIMILAR WIND PATTERN IS EXPECTED TOMORROW
WITH SPEEDS AROUND 5 MPH LOWER THAN TODAY. THE BREEZY CONDITIONS
WILL ALSO EXPAND INTO THE WESTERN DISTRICTS TOMORROW. THESE BREEZY
CONDITIONS AND LOW RHS COULD RESULT IN SOME ELEVATED FIRE DANGER
IN SOME AREAS THIS WEEKEND. A LOW PRESSURE SYSTEM WILL MOVE INTO
THE REGION EARLY NEXT WEEK. WHILE THIS SYSTEM WILL BRING COOLER
CONDITIONS IT WILL ALSO BRING MORE BREEZY TO WINDY CONDITIONS
LIKELY LEADING TO A CONTINUATION OF ELEVATED FIRE DANGER.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
DISCUSSION...BERISLAVICH/RYAN
AVIATION...18
FIRE WEATHER...BERISLAVICH/RYAN
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