896
FXUS65 KPSR 162044
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
144 PM MST WED SEP 16 2026
KEY MESSAGES
- SCATTERED TO WIDESPREAD SHOWERS AND STORMS ARE FORECAST TO
CONTINUE TODAY ACROSS ARIZONA, WITH AREAS OF HIGH RAINFALL
AMOUNTS LEADING TO FLASH FLOODING.
- A FLOOD WATCH REMAINS IN EFFECT THROUGH EARLY TONIGHT ACROSS
MUCH OF SOUTHERN ARIZONA.
- SHOWER AND THUNDERSTORM CHANCES WILL GREATLY DIMINISH BY
THURSDAY AND COME TO AN END STARTING FRIDAY WITH MUCH DRIER
AIR MOVING IN AND LASTING THROUGH AT LEAST THIS WEEKEND.
- BELOW NORMAL TEMPERATURES ARE EXPECTED TODAY ACROSS SOUTH-
CENTRAL ARIZONA, BEFORE WARMING BACK TO TO SLIGHTLY ABOVE
NORMAL LEVELS BY THE WEEKEND.
SHORT TERM /TODAY THROUGH FRIDAY/
RAP40 500MB HEIGHT ANALYSIS SHOWS BROAD TROUGHING OVER WESTERN
CONUS, WITH THE LOW CENTERED OVER NORTHERN CALIFORNIA, AND RIDGING
OVER THE SOUTHERN GULF STATES. THIS PLACES THE DESERT SW SANDWICHED
BETWEEN THESE TWO LARGER FEATURES, KEEPING FLOW ALOFT MOSTLY OUT OF
THE SOUTH-SOUTHWEST, ADVECTING MOISTURE INTO THE REGION FROM NORTHERN
MEXICO. MORE IMPACTFUL, A WELL DEFINED LOW PRESSURE CIRCULATION IS
SEEN ON SATELLITE ALONG THE WEST COAST OF SONORA, MX. THIS FEATURE
IS FORECASTED TO CONTINUE MOVING STRAIGHT NORTH UP THROUGH AZ LIKELY
THIS AFTERNOON THROUGH TONIGHT AND HELP PROVIDE THE LIFT THAT HAS
BEEN SOMEWHAT LACKING. THE ATMOSPHERE IS PRIMED WITH AMPLE MOISTURE,
WITH 1000-700MB MIXING RATIOS FROM THIS MORNING'S 12Z SOUNDING AT 14
G/KG AND PWATS AT 1.90", UPWARDS OF 200% OF NORMAL. WITH THIS
MOISTURE IN PLACE THE LIFT FROM THE PREVIOUSLY MENTIONED LOW WILL BE
BE STRENGTHENED BY THE UPPER LEVEL JET TO THE REGION'S NORTH
PROVIDING EXTRA SUPPORT. MODELS ARE FORECASTING MUCAPE TO BE
GENERALLY BETWEEN 1500-2000 J/KG THIS AFTERNOON, HOWEVER, SOME
MODELS ARE SHOWING SUPPORT FOR UPWARDS OF 2500 J/KG, WITH CIN BELOW
-100 J/KG. WITH ANY DECENT LIFT, THIS WOULD MAKE FOR A FAVORABLE
ENVIRONMENT FOR STORMS TO DEVELOP AND CONTINUE, POSSIBLE EVEN
TRAINING LEADING TO HEAVY RAINFALL, ESPECIALLY THIS AFTERNOON AND
INTO THE LATER EVENING HOURS.
A FLOOD WATCH IS CURRENTLY IN EFFECT FOR SOUTH-CENTRAL AZ AND WILL
CONTINUE THROUGH 11 PM MST TONIGHT. THE WATCH WAS ISSUED LARGELY DUE
TO THE SYNOPTIC AND MESOSCALE SETUP BEING SUPPORTIVE OF SCATTERED TO
WIDESPREAD SHOWERS AND STORMS CAPABLE OF PRODUCING 1-HR RAIN RATES
UP AROUND 1-2" AND HIGHER OVER SHORTER TIME FRAMES, ESPECIALLY IN
THE EASTERN HIGH TERRAIN. SO FAR THIS MORNING, LOCALIZED AREAS IN
THE EASTERN PHOENIX, THE NORTHERN FOOTHILLS AND EASTERN HIGH TERRAIN
HAVE RECEIVED BETWEEN 1.5"-2.75". HI-RES MODELING CONTINUES TO SHOW
ADDITIONAL QPF UPWARDS OF 1-2.5" OVER A LARGE PORTION OF SOUTH-
CENTRAL AZ, AND THERE ARE EVEN HIGH END AMOUNTS UP TO AROUND 3"-4",
ALTHOUGH CHANCES ARE LIMITED, AND ISOLATED IN NATURE. WITH
EVERYTHING COMING TOGETHER AND STARTING TO DEVELOP AS WE HEAD INTO
THE AFTERNOON HOURS WPC DAY 1 ERO GUIDANCE REMAINS AS A MODERATE
RISK FOR ALL OF GILA COUNTY AND MOST OF MARICOPA COUNTY. A SLIGHT
ERO RISK REMAINS FROM FAR WESTERN MARICOPA AND WESTWARDS NEAR TO
AZ/CA STATE BORDER. THE LAST TIME A MODERATE RISK COVERED THIS AREA
WAS BACK IN 2022.
TODAY WILL BE THE PEAK OF THE ACTIVITY AS THE LOW CIRCULATION WILL
MOVE NORTH OF THE AREA BY LATE TONIGHT, BUT A NARROW AXIS OF SHOWERS
AND STORMS MAY LINGER INTO THE OVERNIGHT HOURS, MOST LIKELY TOWARD
EASTERN AZ. ONCE THE SYSTEM FULLY EXITS THE REGION THE ENVIRONMENT
WILL BE TOO OVERWORKED, AND SUBSIDENCE INCREASES ON THE BACK SIDE OF
THE LOW. THIS WILL RESULT IN DRIER AIR BEGINNING TO ADVENT INTO THE
REIGN WITH WEST TO SOUTHWESTERLY FLOW ALOFT. THESE CONDITIONS WILL
LIMIT SHOWERS AND STORMS MOSTLY TO NORTHERN AZ HIGH TERRAIN ON
THURSDAY, FALLOWED BY FURTHER DRYING BY FRIDAY, LIMITING SHOWERS
ACROSS EVEN THE HIGHER TERRAIN, AND 1000-700 MB MIXING RATIOS DROP
TO 8 G/KG OR BELOW, AND PWATS WILL ALSO DECREASE TO SUB 1.00".
TEMPERATURES THIS AFTERNOON MAY STRUGGLE TO REACH 90 DEGREES ACROSS
SOUTH-CENTRAL AZ, WITH AMPLE CLOUD COVER AND RAIN AROUND, WHILE
AREAS FURTHER WEST, WITH MORE SUN, STILL WARM INTO THE MIDDLE 90S TO
AROUND 100 DEGREES. TEMPERATURES WILL WARM BACK UP BY THE END OF THE
WEEK, BUT ONLY BACK TO AROUND SEASONAL LEVELS, WITH HIGHS AROUND 100
DEGREES ACROSS THE LOWER DESERTS, AS BROAD TROUGHING REMAIN IN PLACE
ACROSS MUCH OF THE WEST.
LONG TERM /SATURDAY THROUGH TUESDAY/
THE MONSOON PATTERN MAY BE DONE AFTER TODAY, SHIFTING INTO THE
TRANSITIONAL SEASON WITH MORE FREQUENT TROUGHS. DRY AIR WILL
CONTINUE TO SPREAD ACROSS THE REGION THROUGH THIS WEEKEND WITH
PWATS FORECAST TO DROP BELOW NORMAL, AS LOW AS 0.4-0.7" ACROSS THE
LOWER DESERTS. THE WILL INHIBIT ANY CHANCE AT RAIN. THE BROAD
TROUGH MOVING THROUGH THE WEST, HELPING DRIVE THE WESTERLY FLOW
AND DRY AIR, IS EXPECTED TO SHIFT EAST INTO THE PLAINS BY THE
START OF NEXT WEEK. GLOBAL ENSEMBLE GUIDANCE THEN SHOWS AN UPPER
LOW MOVING OUT OF THE PACIFIC TOWARD THE SOCAL COAST BY THE END OF
THE DAY MONDAY. THERE IS STILL PLENTY OF UNCERTAINTY REGARDING
THIS LOW THIS FAR OUT, BUT IT MAY BE WHAT HELPS EVENTUALLY DRIVE
MOISTURE BACK UP IN THE DESERTS AND DRIVE THE NEXT CHANCE AT RAIN.
AVERAGE TO SLIGHTLY ABOVE AVERAGE TEMPERATURES ARE FORECAST THIS
WEEKEND THROUGH THE FIRST HALF OF NEXT WEEK WITH THIS FORECAST,
WITH AFTERNOON HIGHS AROUND TO SLIGHTLY ABOVE 100 DEGREES. WITH
THE DRIER AIR COMING IN, THE MORNING LOWS WILL FINALLY BE MORE
PLEASANT, CONSISTENTLY DROPPING INTO THE 70S FOR MOST LOWER
DESERT LOCATIONS.
AVIATION
UPDATED AT 1615Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
FORECAST CONTINUES TO REMAIN ON TRACK WITH MAJOR OPERATIONAL
IMPACTS LIKELY THIS AFTERNOON THROUGH THIS EVENING. CLUSTERS OF
THUNDERSTORMS ARE EXPECTED TO DEVELOP WITHIN THE VICINITY IN THE
NEXT COUPLE OF HOURS WITH THE CURRENT GUIDANCE INDICATING THE
HIGHEST DIRECT IMPACTS LIKELY BY THE MID TO LATE AFTERNOON HOURS
AND POSSIBLY LINGERING INTO THE EVENING HOURS. OVERALL WIND
DIRECTION SHOULD REMAIN OUT OF THE SOUTHEAST BEFORE ACTIVITY
MATERIALIZES WITH THE POTENTIAL FOR GUSTY AND ERRATIC WINDS AS
THUNDERSTORM ACTIVITY INCREASES IN COVERAGE WITHIN THE VICINITY.
FOR MOST OF THE PERIOD, WINDS SHOULD GENERALLY MAINTAIN AN
EASTERLY COMPONENT.
IN ADDITION TO DIRECT THUNDERSTORM IMPACTS, INSTANCES OF MVFR AND
POSSIBLY BRIEF IFR FLIGHT CATEGORIES ARE POSSIBLE IN THE FORM OF
LOWERED CIGS (AS LOW AS 4-5 KFT WITH TSRA) AND VISIBILITIES.
SHRA ACTIVITY WILL LIKELY LINGER WELL INTO THE EVENING AND
OVERNIGHT HOURS WITH LOWER PROBABILITIES OF TSRA AND THUS HAVE
MAINTAINED A PROB30 MENTION FOR THIS EVENING FOR TSRA AS THERE IS
HIGH UNCERTAINTY. VCSH LOOK TO LINGER THROUGH 10-12Z THURSDAY
MORNING WITH BKN CIGS BETWEEN 5-7 KFT LOOKING TO LINGER BEFORE
SCATTERING OUT BY THE MID TO LATE MORNING HOURS.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR WEATHER ISSUES WILL EXIST THROUGH THE TAF PERIOD UNDER
MOSTLY CLEAR SKIES, WITH FEW LOW (AOA 7-9 KFT) AND HIGH CLOUDS
MOVING IN AT THE END OF THE TAF PERIOD. AT KIPL, WINDS WILL
GENERALLY BE OUT OF THE SOUTHEAST WITH SOME GUSTS INTO THE MID TO
UPPER TEENS LATER THIS AFTERNOON THROUGH EARLY THIS EVENING. AT
KBLH, SOUTHERLY WINDS ARE EXPECTED THROUGH THE AFTERNOON WITH
PERIODIC GUSTS BETWEEN 20-25 KTS. THERE CONTINUES TO BE INCREASING
CONFIDENCE THAT AN OUTFLOW FROM THE CONVECTIVE COMPLEX IN AZ WILL
LIKELY AFFECT KBLH BY THE EARLY EVENING HOURS, SHIFTING THE WINDS
MORE OUT OF THE EAST WITH POTENTIALLY SOME GUSTS BETWEEN 20-25 KTS
AND MAYBE SOME REDUCED VISIBILITIES DUE TO SOME BLDU, ALTHOUGH
CONFIDENCE OF BLDU MATERIALIZING IS LOW AT THIS TIME. WINDS ACROSS
BOTH TERMINAL SITES SHOULD BECOME MOSTLY LIGHT AND VARIABLE DURING
THE OVERNIGHT AND EARLY MORNING HOURS.
FIRE WEATHER
PERIODS OF SCATTERED TO WIDESPREAD SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO CONTINUE TODAY, FOCUSING MOSTLY ACROSS THE EASTERN
DISTRICTS THIS AFTERNOON THROUGH THIS EVENING, HOWEVER WIDESPREAD
ACTIVITY OVER MUCH OF THE LOWER DESERTS CAN BE EXPECTED. THERE
WILL BE A HEAVY RAINFALL AND FLOOD THREAT WITH THE ACTIVITY.
MOISTURE LEVELS WILL BE ELEVATED MOST AREAS, HIGHEST ACROSS
EASTERN DISTRICTS, WHERE MINIMUM RH THIS AFTERNOON WILL BE AROUND
50-60%. MINIMUM RHS WILL BE LOWEST ACROSS SOUTHEAST CA, WITH
VALUES AROUND 20-30%. A DRYING TREND WILL BEGIN THURSDAY WITH
CONDITIONS BECOMING VERY DRY BY THIS WEEKEND. MINIMUM RHS BY
SATURDAY DIP TO 10-25% ACROSS THE LOWER DESERTS (LOWEST ACROSS
WESTERN DISTRICTS). OVERNIGHT RECOVERIES WILL STILL BE GOOD ACROSS
EASTERN DISTRICTS THIS WEEKEND AT 40-60%, WHILE WESTERN DISTRICTS
HOVER AROUND 25-45%. THE DRIER AIR MOVING IN WILL ELIMINATE RAIN
CHANCES BY FRIDAY, WITH LOW CHANCES IN GILA COUNTY THURSDAY
AFTERNOON. WINDS WILL FAVOR THE SOUTH TO SOUTHEAST OVER MUCH OF
THE AREA THROUGH WEDNESDAY WITH GUSTS OF 20-30 MPH AT TIMES ACROSS
SOUTHWEST AZ AND SOUTHEAST CA. IN THE FOLLOWING DAYS WINDS WILL
RETURN TO A MORE TYPICAL DIURNAL WITH MODEST AFTERNOON UPSLOPE
GUSTINESS.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...FLOOD WATCH UNTIL 11 PM MST THIS EVENING FOR AZZ531-533-534-
536>563.
CA...NONE.
SHORT TERM...RYAN/BENEDICT
LONG TERM...BENEDICT
AVIATION...LOJERO
FIRE WEATHER...RYAN/BENEDICT
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page