838
FXUS65 KPSR 302301
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
400 PM MST WED SEP 30 2026
UPDATE
UPDATED AVIATION
KEY MESSAGES
- ASIDE FROM A FEW SHOWERS POSSIBLE IN FAR EASTERN GILA COUNTY THIS
AFTERNOON, DRY CONDITIONS WITH NEAR ZERO RAIN CHANCES WILL PERSIST
THE NEXT SEVERAL DAYS.
- AS HIGH PRESSURE GRADUALLY BUILDS OVER THE REGION, A GRADUAL
WARMING TREND IS EXPECTED WITH NEAR TO SLIGHTLY ABOVE NORMAL
TEMPERATURES RETURNING BY THE END OF THE WEEK AND INTO THE WEEKEND.
SHORT TERM /TODAY THROUGH FRIDAY/
LATEST WATER VAPOR SATELLITE IMAGERY INDICATED THE UPPER LOW
RESPONSIBLE FOR THE ACTIVE WEATHER THE LAST COUPLE OF DAYS IS
CURRENTLY CENTERED OVER NM. MUCH OF THE AREA IS CURRENTLY ON THE
SUBSIDENT SIDE OF THE LOW WITH DRIER AIR BUILDING IN. A FEW SHOWERS,
HOWEVER, MAY STILL DEVELOP MAINLY ACROSS FAR EASTERN GILA COUNTY
THIS AFTERNOON ALONG THE DEFORMATION ZONE ON THE BACK SIDE OF THE
LOW. OTHERWISE, WITH THE DRIER AIR AND RIDGING ALOFT GRADUALLY
BUILDING IN FROM THE EASTERN PACIFIC, DRY CONDITIONS WITH ZERO RAIN
CHANCES WILL PREVAIL THROUGH THE REST OF THE WEEK UNDER MOSTLY CLEAR
SKIES.
DUE TO THE LINGERING INFLUENCES OF THE NEGATIVE 500 MB HEIGHT
ANOMALIES FROM THE DEPARTING UPPER LOW, AFTERNOON HIGH TEMPERATURES
TODAY ACROSS MUCH OF THE SOUTH-CENTRAL AZ LOWER DESERTS WILL ONLY
TOP OUT IN THE LOW 80S, WHICH IS A SOLID 10 DEGREES BELOW NORMAL FOR
THIS TIME OF THE YEAR, WHILE WARMER READINGS IN THE 90S CAN BE
EXPECTED ACROSS THE WESTERN DESERTS. AS THE RIDGING ALOFT GRADUALLY
BUILDS OVER THE REGION DURING THE NEXT COUPLE OF DAYS, TEMPERATURES
THROUGH THE END OF THE WEEK WILL GRADUALLY WARM UP WITH LOWER DESERT
HIGHS RETURNING TO THE MID 90S ACROSS SOUTH-CENTRAL AZ TO AROUND 100
DEGREES ALONG AND WEST OF THE LOWER COLORADO RIVER VALLEY 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 2300Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
UNCERTAINTY IN WIND DIRECTIONS AND TIMING OF WIND SHIFTS IS THE MAIN
WEATHER ISSUE THROUGH THURSDAY EVENING AS MIDLEVEL CLOUD DECKS
RAPIDLY CLEAR THIS EVENING. WITH A SFC LOW DIRECTLY OVER THE PHOENIX
METRO, WINDS WILL TRULY BE LIGHT AND VARIABLE THROUGH MID EVENING
BEFORE OBTAINING THE TYPICAL EASTERLY DRAINAGE COMPONENT.
WIND DIRECTIONS MAY ATTEMPT TO BECOME W/NW THURSDAY AFTERNOON,
HOWEVER MAY ONLY BECOME VARIABLE BEFORE REVERTING TO AN EASTERLY
FETCH.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO WEATHER ISSUES WILL EXIST THROUGH THURSDAY EVENING UNDER CLEAR
SKIES. WHILE A LIGHT S/SE WIND COMPONENT WILL BE FAVORED THROUGH THE
PERIOD, AN EXTENDED TIME FRAME OF NEARLY CALM CONDITIONS WILL BE
COMMON.
FIRE WEATHER
ASIDE FROM A FEW AFTERNOON SHOWERS ACROSS THE FAR EASTERN DISTRICTS
TODAY, DRY CONDITIONS WILL PREVAIL DURING THE NEXT SEVERAL DAYS.
TEMPERATURES WILL REMAIN BELOW NORMAL ACROSS SOUTH-CENTRAL AZ AND
NEAR NORMAL FOR AREAS ALONG AND WEST OF THE COLORADO RIVER VALLEY
THROUGH THE REST OF THIS WEEK WITH GRADUAL WARMING ANTICIPATED
THROUGH THE WEEKEND. RELATIVE HUMIDITY WILL BOTTOM OUT AROUND 15-30%
ACROSS THE WESTERN DISTRICTS AND REMAIN ABOVE 40% ACROSS THE EASTERN
DISTRICTS THROUGH THE END OF THE WEEK ALONG WITH GOOD TO EXCELLENT
OVERNIGHT RECOVERIES. WINDS WILL BE LIGHT AND DIURNAL 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...LOJERO
LONG TERM...SALERNO
AVIATION...18
FIRE WEATHER...LOJERO/SALERNO
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page