726
FXUS65 KPSR 301710
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1010 AM MST WED SEP 30 2026
UPDATE
18Z AVIATION DISCUSSION
KEY MESSAGES
- A GRADUAL WARMING TREND IS ANTICIPATED THROUGH THE REMAINDER OF
THIS WEEK AND INTO THIS WEEKEND. LOWER DESERT HIGHS WILL RETURN
TO NEAR NORMAL ACROSS SOUTHCENTRAL AZ AND SLIGHTLY ABOVE NORMAL
FOR AREAS A LONG AND WEST OF THE LOWER COLORADO RIVER VALLEY.
- ASIDE FROM LINGERING ISOLATED SHOWER ACTIVITY IN SOUTHERN GILA
COUNTY TODAY, DRY CONDITIONS WILL RETURN TO THE REGION THROUGH
EARLY NEXT WEEK AS HIGH PRESSURE TAKES HOLD OVER THE REGION.
SHORT TERM /TODAY THROUGH FRIDAY/
LATEST GOES SATELLITE WV IMAGERY AND 500 MB STREAMLINE ANALYSIS
REVEALS A DEEP CUTOFF LOW WHICH IS CENTERED DIRECTLY OVER GILA
COUNTY. THIS LOW HAS BEEN RESPONSIBLE FOR PERIODS OF SHOWERS AND
STORMS ACROSS THE DESERT SOUTHWEST DURING THE LAST 48 HOURS WITH
SOME LOCATIONS RECEIVING OVER 2.00" OF RAINFALL. A GOOD CHUNK OF
SOUTHCENTRAL AZ RECEIVED AROUND 0.25"-1.00" OF RAIN WITH THE
HIGHEST TOTALS RESIDING OVER NORTHERN AND WESTERN MARICOPA COUNTY
AND S GILA COUNTY. A FEW WRAP AROUND SHOWERS AND STORMS ARE
CURRENTLY DEVELOPING WITHIN THE PROXIMITY OF THE UPPER-LOW AND
THIS WILL LIKELY CONTINUE THROUGH THE REST OF THIS MORNING AND
INTO THE EARLY AFTERNOON AS THE LOW CENTER SLOWLY MIGRATES EWD.
THESE SHOWERS MAY PRODUCE AN ADDITIONAL FEW HUNDREDTHS TO A TENTH
OF AN INCH OF RAINFALL. DRY AIR WILL GRADUAL FILTER IN BEHIND THIS
SYSTEM AS PWAT VALUES FALL BELOW 1.00" LATE THIS AFTERNOON AND
EVENING, ULTIMATELY ENDING RAIN CHANCES REGION-WIDE. DRY CONDITIONS
WILL PREVAIL THROUGH THE REMAINDER OF THIS WEEK WITH ESSENTIALLY
NO RAIN CHANCES EXPECTED ACROSS THE ENTIRE DESERT SOUTHWEST.
DUE TO THE PRESENCE OF NEGATIVE 500 MB HGHT ANOMALIES AND
ELEVATED SOIL MOISTURE FROM YESTERDAY'S WIDESPREAD RAINFALL, SFC
TEMPERATURES ARE EXPECTED TO REMAIN WELL BELOW NORMAL ACROSS
SOUTHCENTRAL AZ THIS AFTERNOON. LOWER DESERT HIGHS WILL MAINLY
RANGE FROM THE LOW TO MID 80S WITH TEMPERATURES ACROSS THE HIGHER
ELEVATIONS IN THE LOW TO MID 70S. FOR AREAS ALONG AND WEST OF THE
LOWER COLORADO RIVER VALLEY, CLEAR SKIES AND A DRIER AIRMASS WILL
ALLOW TEMPERATURES TO CLIMB TO AROUND NORMAL MAINLY IN THE LOW TO
MID 90S. UPPER-LVL RIDGING WILL BEGIN TO BUILD IN BEHIND THE
DEPARTING WEATHER SYSTEM THURSDAY AND FRIDAY, CAUSING TEMPERATURES
TO STEADILY CLIMB AROUND 3-5 DEGREES EACH DAY. LOWER DESERT HIGHS
SHOULD RETURN TO THE MID 90S TO AROUND 100 DEGREES BY FRIDAY.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
MODEL GUIDANCE SHOWS UPPER-LVL RIDGING MIGRATING OVER THE FOUR
CORNERS REGION BY THIS WEEKEND WITH 500 MB HGHT FIELDS INCREASING
TO AROUND 588-590 DAM. AS THIS OCCURS, GLOBAL MODELS SHOW A WEAK
UPPER- LOW DEVELOPING OVER N MX AND FAR W TX WHICH WILL INDUCE
EASTERLY FLOW ALOFT OVER OUR FORECAST AREA. THE INCREASED PRESSURE
GRADIENT BETWEEN BOTH FEATURES WILL BRING BREEZY CONDITIONS TO
SOUTHEASTERN AND SOUTHCENTRAL AZ FROM SATURDAY THROUGH MONDAY.
ELEVATED WINDS WILL LIKELY DEVELOP EACH MORNING AND PERSIST INTO
THE EARLY AFTERNOON WITH GUSTS REACHING 30-35 MPH OVER THE HIGH
TERRAIN AND 20- 25 MPH ACROSS THE LOWER DESERTS. THIS SFC EASTERLY
FLOW WILL HELP KEEP HIGH TEMPERATURES NEAR NORMAL ACROSS
SOUTHCENTRAL AZ, BUT OVERNIGHT LOWS WILL BE ELEVATED IN THE LOW TO
MID 70S. THE 500 MB RIDGE AXIS LOOKS TO SHIFT BACK TO THE OVER
SOCAL AND THE GREAT BASIN EARLY NEXT WEEK AS A WEAK TROUGH PASSES
THROUGH THE INTERMOUNTAIN WEST. THIS PATTERN SHOULD MAINTAIN
TEMPERATURES IN A NEAR NORMAL RANGE ACROSS CENTRAL AND EASTERN
PORTIONS OF THE REGION, BUT ALLOW HIGHS TO WARM AROUND 3-5 DEGREES
ABOVE NORMAL ACROSS THE WESTERN DESERTS WHERE HIGHS WILL LIKELY
REACH THE LOW 100S EACH AFTERNOON.
AVIATION
UPDATED AT 1710Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO MAJOR AVIATION CONCERNS ARE EXPECTED DURING THE TAF PERIOD.
WINDS WILL BE VERY LIGHT WITH EXTENDED PERIODS OF VRB CONDITIONS.
THE TYPICAL WESTERLY SHIFT IS NOT ANTICIPATED THIS AFTERNOON,
THOUGH SOME OCCASIONAL OBSERVATIONS ARE STILL LIKELY. CLOUD DECKS
AS LOW AS 6-8 KFT WILL LINGER THROUGH EARLY THIS AFTERNOON AHEAD
OF CLEAR SKIES THROUGH THE REMAINDER OF THE FORECAST.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO AVIATION CONCERNS ARE EXPECTED DURING THE NEXT 24 HOURS UNDER
CLEAR SKIES. OUTSIDE OF EXTENDED PERIODS OF VRB CONDITIONS,
SOUTHERLY/SOUTHEASTERLY FLOW WILL BE COMMON AT BOTHER TERMINALS,
WITH SPEEDS GENERALLY AOB 10 KT.
FIRE WEATHER
AFTER THE LAST COUPLE DAYS OF ABUNDANT WETTING RAINFALL, DRIER
CONDITIONS ARE EXPECTED TO RETURN TODAY AS A WEATHER SYSTEM
DEPARTS THE REGION. TEMPERATURES WILL REMAIN WELL BELOW NORMAL
ACROSS SOUTHCENTRAL AZ AND NEAR NORMAL FOR AREAS ALONG AND WEST
OF THE COLORADO RIVER VALLEY THROUGH THE REST OF THIS WEEK WITH
GRADUAL WARMING ANTICIPATED BY THIS WEEKEND. RELATIVE HUMIDITY
WILL BOTTOM OUT AROUND 15-30% ACROSS THE WESTERN DISTRICTS AND
REMAIN ABOVE 40% ACROSS THE EASTERN DISTRICTS TODAY AND THURSDAY.
GOOD TO EXCELLENT OVERNIGHT RECOVERIES CAN BE EXPECTED THROUGH THE
REMAINDER OF THIS WEEK. WINDS WILL RETURN TO LIGHT AND DIURNAL
PATTERNS WITH SPEEDS REMAINING PREDOMINANTLY 10 MPH OR LESS OVER
THE NEXT FEW DAYS BEFORE A STRONGER EASTERLY GRADIENT WIND SETS IN
BY THIS WEEKEND.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...SALERNO
LONG TERM...SALERNO
AVIATION...RW
FIRE WEATHER...SALERNO
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