564
FXUS65 KPSR 301701
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1000 AM MST THU APR 30 2026
UPDATE
UPDATED AVIATION
KEY MESSAGES
- NEAR NORMAL TEMPERATURES WILL TURN HOTTER OVER THE WEEKEND WITH
LOWER DESERT HIGHS INTO THE NINETIES AS EARLY AS FRIDAY.
- A WEATHER SYSTEM APPROACHING THE WEST COAST WILL TIGHTEN THE
PRESSURE GRADIENT RESULTING IN WIDESPREAD BREEZY TO WINDY CONDITIONS
SATURDAY AND SUNDAY.
- THE COMBINATION OF LOW AFTERNOON RELATIVE HUMIDITIES AND GUSTY
WINDS WILL LIKELY LEAD TO ELEVATED FIRE WEATHER CONCERNS THIS
WEEKEND.
SHORT TERM /TODAY THROUGH THURSDAY/
CURRENT OBJECTIVE ANALYSIS SHOW THE CENTER OF THE CLOSED LOW NOW TO
THE REGION'S SW, OFF THE WESTERN COAST OF BAJA PENINSULA. THIS
SYSTEM CONTINUES TO TRACK MORE TO OUR SOUTH, ACROSS NORTHERN MEXICO,
RESULTING IN RAINFALL CHANCES TO BE MOSTLY CONFINED TO SOUTHEASTERN
ARIZONA. MID TO UPPER LEVEL MOISTURE WILL INCREASE WITH THE PASSING
OF THIS SYSTEM, HOWEVER, ANY ACTIVITY IN OUR CWA WILL BE LIMITED TO
MOSTLY VIRGA WITH SLIGHTLY HIGHER PROBABILITIES (5-10%) OVER THE
HIGHER TERRAIN OF GILA COUNTY. EVEN THOUGH MOST OF THE ACTIVITY IS
EXPECTED TO BE TO THE REGION'S SE, THE HRRR AND NAM MODELS SHOW
STRONG OUTFLOWS REACHING SOUTH-CENTRAL ARIZONA BY THIS EVENING, AND
COULD LAST UP TO MIDNIGHT TONIGHT. THIS CAN LEAD TO WIND GUSTS UP TO
35 MPH AND AREAS OF PATCHY BLOWING DUST.
OTHERWISE TEMPERATURES TODAY WILL BE IN THE LOW 90S ACROSS THE LOWER
DESERTS, AND IN THE MID 80S IN THE HIGHER TERRAIN AREAS. BY FRIDAY
THE CLOSE LOW WILL BE EXITING TO THE REGION'S EAST, AND RIDGING WILL
BEGIN TO BUILD OVER THE WEST COAST. WITH RIDGING TO THE REGION'S
WEST, TEMPERATURES WILL BEGIN TO WARM INTO THE LOWER TO MID 90S
ACROSS THE LOWER DESERTS WITH THE WESTERN PORTIONS LEANING MORE
TOWARDS THE MID 90S RANGE.
LONG TERM /FRIDAY THROUGH TUESDAY/
ANOTHER CLOSED LOW IS PROJECTED TO FORM FROM A SHORTWAVE TROUGH
ORIGINATING IN THE GULF OF ALASKA, BEFORE DEVELOPING INTO A CLOSED
LOW OFF THE COAST OF NORTHERN CALIFORNIA. THIS WILL HELP AMPLIFY THE
RIDGE OVER THE DESERT SW DRIVING TEMPERATURES INTO THE MID TO UPPER
90S THROUGHOUT THE WEEKEND. THIS NEXT CLOSED LOW IS EXPECTED TO MOVE
INLAND INTO NORTHERN CALIFORNIA BY SUNDAY EVENING, WHICH WILL MOST
LIKELY RETURN BREEZY TO WINDY CONDITIONS, COOLER TEMPERATURES, AND
POSSIBLY SOME HIGHER TERRAIN RAIN CHANCES. CONTINUED MONITORING OF
THIS SYSTEM WILL BE NEEDED OVER THE NEXT SEVERAL DAYS.
AVIATION
UPDATED AT 1700Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
THE PRIMARY WEATHER CONCERN WILL BE THE POTENTIAL FOR GUSTY OUTFLOW
WINDS THIS EVENING AS MID/HIGH CLOUD DECKS GENERALLY INCREASE
THROUGH THE EVENING/OVERNIGHT. CONFIDENCE IS VERY GOOD THAT EAST
WINDS WILL GRADUALLY SWITCH TO WEST THROUGH THE AFTERNOON WITH A
PERIOD OF VARIABILITY (140V240) OR LIGHT SOUTHERLY CROSS RUNWAY
WINDS BEFORE FINALIZING THE WIND SHIFT. FORECAST CONFIDENCE
DETERIORATES AFTER THIS AS SHRA/TSRA IN FAR SE ARIZONA ATTEMPTS TO
SEND SOME FORM OF AN OUTFLOW BOUNDARY NORTH TOWARDS THE PHOENIX AREA
TERMINALS THIS EVENING. ARRIVAL TIMING, MAGNITUDE OF GUSTS, AND
IMPACTS REMAIN VERY UNCERTAIN, HOWEVER A MID EVENING ARRIVAL WITH
GUSTS AROUND 20KT ARE A MODEL CONSENSUS. SOME LOFTED DUST/HAZE
AFFECTING SLANTWISE VSBY SEEMS LIKELY WITH RESTRICTIONS TO SFC VSBY
CARRYING FAR LOWER ODDS. GUSTS MAY PERSIST FOR A FEW HOURS INTO THE
OVERNIGHT BEFORE SETTING ON A MODEST E/SE COMPONENT THROUGH MID
MORNING.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
LOCALLY GUSTY WEST WINDS WILL BE THE PRIMARY WEATHER ISSUE THROUGH
FRIDAY AFTERNOON UNDER PERIODS OF MID/HIGH CLOUD DECKS. CONFIDENCE
IS GOOD THAT W/NW WIND DIRECTIONS WILL BE PREFERRED THROUGH THE
PERIOD ACROSS SE CALIFORNIA. SUNDOWNER GUSTS 20-30 KT APPEAR LIKELY
AT KIPL THROUGH LATE EVENING BEFORE RELAXING OVERNIGHT. SOME
VARIABILITY IN WIND DIRECTIONS IS POSSIBLE FRIDAY MORNING AFTER
SUNRISE.
FIRE WEATHER
DRY CONDITIONS AND WARMING TEMPERATURES WILL BE OBSERVED THROUGH THE
WEEKEND. MINRH VALUES WILL BE AROUND 10-15% TODAY BEFORE INCREASING
SLIGHTLY TO 15-20% OVER THE WEEKEND. MAXRH VALUES TONIGHT WILL
GENERALLY RANGE BETWEEN 30-60% BEFORE DECREASING SLIGHTLY TO 20-50%
OVER THE WEEKEND. GUSTY WINDS ARE EXPECTED TO INCREASE THIS EVENING
AND OVER THE WEEKEND INTO EARLY NEXT WEEK, WHICH COULD LEAD TO
ELEVATED FIRE WEATHER CONDITIONS IN SOME AREAS.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...RYAN
LONG TERM...RYAN
AVIATION...18
FIRE WEATHER...95/RYAN
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