101
FXUS65 KPSR 170547
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1045 PM MST FRI OCT 16 2026
UPDATE
06Z AVIATION DISCUSSION
KEY MESSAGES
- WIND ADVISORIES CONTINUE ACROSS PORTIONS OF THE REGION THROUGH
SATURDAY MORNING WITH GUSTS OCCASIONALLY OVER 35 MPH RESULTING IN
AREAS OF BLOWING DUST AND DIFFICULT TRAVEL FOR HIGH PROFILE
VEHICLES.
- A SLIGHT CHANCE OF LIGHT RAIN WILL ARRIVE INTO PARTS OF SOUTH-
CENTRAL ARIZONA OVER THE WEEKEND WITH THE BETTER CHANCES FOCUSED
OVER HIGHER TERRAIN LOCATIONS.
- A PACIFIC LOW PRESSURE SYSTEM MOVING INTO THE SOUTHWEST DURING THE
MIDDLE OF NEXT WEEK WILL LEAD TO MUCH BETTER RAINFALL CHANCES WITH
THE POSSIBILITY OF A FEW EMBEDDED THUNDERSTORMS, AS WELL AS COOLER
TEMPERATURES
SHORT TERM /TODAY THROUGH SUNDAY/
AS FULL LATITUDINAL TROUGHING DEEPENS OVER THE EASTERN CONUS, A
MATURE HIGH AMPLITUDE REX BLOCK REMAINS ESTABLISHED OVER THE WESTERN
HALF OF THE COUNTRY. THIS PATTERN CONTINUES TO PROMOTE STRONG SFC
HIGH PRESSURE OVER THE CENTRAL ROCKIES/HIGH PLAINS, AND COMBINED
WITH INVERTED LOW PRESSURE EMANATING FROM THE GULF OF CALIFORNIA, AN
INTENSE PRESSURE GRADIENT HAS DEVELOPED ACROSS THE CWA. AN H9-H8 30-
50KT EASTERLY LLJ HAS WEAKENED EARLY THIS AFTERNOON AS THE THERMAL
ENHANCEMENT HAS DETERIORATED, BUT LINGERING GUSTY WINDS AND LOFTED
DUST WILL CONTINUE TO IMPACTS MANY AREAS THROUGH THE OVERNIGHT.
WHILE LOWER ELEVATIONS WILL EXPERIENCE PARTIAL DECOUPLING AND MUCH
WEAKER WINDS AFTER SUNSET, RIDGE TOPS AND THE TYPICAL WIND PRONE
AREAS WILL LIKELY CONTINUE TO RECORD GUSTY WINDS PUSHING ADVISORY
CRITERIA THROUGH THE OVERNIGHT. THE COMBINED EFFECT OF A
SIGNIFICANTLY LOOSENED PRESSURE GRADIENT AND THICKER CLOUDS
COMPROMISING MECHANICAL MIXING WILL PRECLUDE ADVISORY CRITERIA
BEYOND SATURDAY MORNING.
THE AFOREMENTIONED REX BLOCK WILL SLOWLY OPEN THIS WEEKEND WITH THE
NEGATIVE HEIGHT ANOMALY PROPAGATING FROM SOUTHERN CALIFORNIA INTO
NORTHERN ARIZONA. THIS PLACES SOUTH-CENTRAL ARIZONA WITHIN A VERY
FAVORABLE LEFT FRONT JET QUADRANT WITH A WEAK COLD CORE SKIRTING THE
FORECAST AREA INDICATIVE OF PERIODS OF ROBUST ASCENT. THE UNDERLYING
SOUTHWEST FLOW WILL ALSO CONCURRENTLY IMPORT THICK MOISTURE THROUGH
THE H7-H5 LAYER SUCH THAT TOTAL COLUMN PWATS REACH 1" BY SATURDAY
AFTERNOON. WHILE THESE PARAMETERS WOULD GENERALLY SUPPORT WIDESPREAD
LIGHT RAIN, A VERY DRY SUB-CLOUD LAYER RESULTING FROM THE PERSISTENT
DOWNSLOPING EASTERLY WINDS WILL BATTLE THE ABILITY FOR PRECIPITATION
REACHING THE GROUND. NEVERTHELESS, GIVEN THE ASCENT STRUCTURE AND
MAGNITUDE OF MIDLEVEL MOISTURE, SOME LIGHT SHOWERS SHOULD REACH THE
SURFACE SATURDAY AFTERNOON THROUGH SUNDAY MORNING WITH THE BEST
CHANCES OVER HIGHER TERRAIN AREAS EAST OF PHOENIX WHERE SFC TO CLOUD
BASE DEPTHS ARE MINIMIZED. OTHERWISE, PARTIAL CLEARING WILL SLOWLY
ADVANCE THROUGH THE FORECAST AREA SUNDAY WITH MOISTURE AND ASCENT
LIFTING INTO NORTHERN ARIZONA.
LONG TERM /MONDAY THROUGH THURSDAY/
THE RIDGE COMPRISING THE NORTHERN PORTION OF THE REX BLOCK WILL PUSH
EASTWARD EARLY NEXT WEEK AS THE UPPER LOW WEAKENS INTO AN OPEN WAVE
AND BECOMES ABSORBED INTO THE MEAN SOUTHWEST FLOW. LINGERING LIGHT
SHOWERS MAY CONTINUE TO AFFECT OROGRAPHICALLY FAVORED AREAS OF THE
EASTERN CWA MONDAY AIDED BY THE NEXT PIECE OF SUBTROPICAL JET ENERGY
ROUNDING TOWARDS THE SOUTHWEST FROM THE EASTERN PACIFIC. IF ACTIVITY
DOES DEVELOP, TOTAL ACCUMULATIONS ARE EXPECTED TO BE FAIRLY MINIMAL.
BY TUESDAY, DEEP TROUGHING AND STRONG NEGATIVE HEIGHT ANOMALIES WILL
AMPLIFY AND INTENSIFY ALONG THE WEST COAST, HOWEVER CONFIDENCE IS
EXACT THE TIMING AND DEPTH OF THIS FEATURE REMAINS LOW TO MODERATE.
AS A RESULT, NOTABLE FORECAST TEMPERATURE SPREAD EXISTS DURING THE
MIDDLE OF NEXT WEEK, IN ADDITION TO UNCERTAINTY IN RAINFALL TIMING
AND AMOUNTS. AT THIS TIME, THE PREPONDERANCE OF MODEL EVIDENCE
POINTS TOWARDS WEDNESDAY AND THURSDAY AS THE MOST LIKELY TO
EXPERIENCE SHOWERS AND EMBEDDED THUNDERSTORMS AHEAD OF THE TROUGH
PASSAGE AND THE INTRODUCTION OF MUCH COOLER, BELOW NORMAL AUTUMNAL
TEMPERATURES.
AVIATION
UPDATED AT 0545Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
MAIN AVIATION CONCERNS WILL BE CONTINUED BREEZINESS AND LINGERING
SLANTWISE VIS REDUCTION DUE TO LOFTED DUST. WINDS THROUGH SUNRISE
WILL BEHAVE SIMILAR TO THE PREVIOUS NIGHT WITH RELATIVELY ELEVATED
SUSTAINED SPEEDS AROUND 10-15 KT AND SPORADIC GUSTS UPWARDS OF 25
KT OR SO. KSDL WILL BE MORE SUSCEPTIBLE TO THESE GUSTS DUE TO
THEIR CLOSER PROXIMITY TO TERRAIN FEATURES AND ORIENTATION OF THE
OVERALL FLOW. THOUGH NOT INCLUDED IN THE TAFS, LOCALIZED LLWS
COULD CREATE OPERATIONAL IMPACTS OVERNIGHT DUE TO WINDS 35-45 KT
A FEW THOUSAND FEET ABOVE THE SURFACE. MORE PERSISTENT BREEZINESS
WILL REEMERGE AFTER SUNRISE BEFORE A NOTICEABLE DOWNTREND IN
SPEEDS TAKE PLACE DURING THE BACK-HALF OF THE FORECAST WINDOW.
SLANTWISE VIS SHOULD BEGIN TO IMPROVE IN CONJUNCTION WITH THE
WEAKENING WINDS. CONSIDERABLE CLOUD COVER WILL BE PRESENT OVER THE
REGION, WITH BASES DROPPING TO 9-12 KFT BY SATURDAY AFTERNOON.
THE THICK CLOUD COVER WILL BE ACCOMPANIED BY ISOLATED SHOWER CHANCES
STARTING SATURDAY AFTERNOON AND EVENING AND VCSH HAS BEEN ADDED TO
EACH OF THE TAFS FROM ABOUT 00Z TO THE END OF THE FORECAST. HOWEVER,
CONFIDENCE IN THIS TIMING IS LOW, AND IT IS NOT OUT OF THE QUESTION
THAT SHOWER ACTIVITY MOVES IN A FEW HOURS SOONER. WITH THAT BEING
SAID, MENTION OF -SHRA HAS BEEN EXCLUDED FROM THE TAFS AS
OPERATIONAL IMPACTS WILL BE MINIMAL AT BEST WITH POTENTIAL ACTIVITY.
TEMPOS THAT INCLUDE THE MENTION OF RAINFALL MAY BE ADDED IN
SUBSEQUENT FORECASTS IF CONFIDENCE INCREASES OR GREATER IMPACTS ARE
EXPECTED.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR AVIATION CONCERNS ARE EXPECTED DURING THE NEXT 24 HOURS.
OUTSIDE OF PERIODS OF VRB CONDITIONS, NE'RLY FLOW WILL BE FAVORED
AT BOTH TERMINALS THROUGH MUCH OF THE FORECAST. ISOLATED GUSTS
UPWARDS OF 25 KT CANNOT BE RULED OUT AT KBLH THROUGH SUNRISE.
ISOLATED SHRA WILL BE SEEN OVER THE REGION TONIGHT, WITH SOME
MOVING WITHIN THE VICINITY OF KIPL. HOWEVER, NO IMPACTS ARE
EXPECTED WITH THIS ACTIVITY. CONSIDERABLE CLOUD COVER WILL BE
PRESENT THROUGH SATURDAY AFTERNOON, WITH THE LOWEST BASES AROUND
9-12 KFT.
FIRE WEATHER
STRONG EAST WINDS WILL CONTINUE THROUGH SATURDAY ACROSS SOUTHERN
ARIZONA WITH THE MOST PRONOUNCED GUSTS OVER MOUNTAIN TOPS OF EASTERN
DISTRICTS DURING THE OVERNIGHT AND EARLY MORNING HOURS. GUSTS 40-45
MPH MAY BE COMMON OVER THESE LOCATIONS WITH A PORTION OF THESE WINDS
BUILDING INTO LOWER ELEVATIONS BY LATE MORNING. SPEEDS WILL SLOWLY
DECREASE THROUGH THE DAY WITH EVEN WEAKER WINDS SUNDAY THROUGH THE
MIDDLE OF NEXT WEEK. LIGHT SHOWERS ARE POSSIBLE THIS WEEKEND, AND
PARTICULARLY OVER EASTERN DISTRICTS, BUT THE CHANCE FOR WETTING
RAIN IS LOW (~10%). THE STRONG EAST WINDS WILL RESULT IN MINIMUM
HUMIDITY LEVELS 20-30% SATURDAY, BUT INCREASING CLOSER TO A 30-50%
RANGE THEREAFTER. OVERNIGHT RECOVERY SHOULD BE GOOD TO EXCELLENT. A
PACIFIC WEATHER DISTURBANCE WILL BRING INCREASED CHANCES OF WETTING
RAINFALL, BREEZY WINDS, AND COOLER TEMPERATURES DURING THE LATTER
HALF OF NEXT WEEK.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...WIND ADVISORY UNTIL 11 AM MST SATURDAY FOR AZZ547-552-553-555-
557-558-560>562.
CA...NONE.
SHORT TERM...18
LONG TERM...18/RYAN
AVIATION...RW
FIRE WEATHER...18/RYAN
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