767
FXUS65 KPSR 171709
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1009 AM MST WED JUN 17 2026
UPDATE...UPDATED 18Z AVIATION DISCUSSION
KEY MESSAGES
- TEMPERATURES UP TO 8 DEGREES ABOVE NORMAL WILL COOL CLOSER TO THE
SEASONAL AVERAGE BY THE END OF THE WEEK ALLOWING MODERATE HEATRISK
TO BE REDUCED TOWARDS A MINOR CATEGORY.
- A SLIGHT CHANCE OF STORMS WILL RETURN THIS AFTERNOON, BUT FOCUSED
EXCLUSIVELY NEAR TERRAIN FEATURES IN ARIZONA.
- AN APPROACHING EAST PACIFIC WEATHER DISTURBANCE LATE THIS WEEK
WILL DRY OUT THE REGION, WHILE BRINGING INCREASINGLY BREEZY
CONDITIONS AND COOLING TEMPERATURES.
SHORT TERM /TODAY THROUGH THURSDAY/
EARLY MORNING WV IMAGERY DEPICTS A VERY COMPLICATED FLOW PATTERN
OVER THE SW CONUS FEATURING AN ANTI-CYCLONE RETROGRADING ACROSS
NEVADA WHILE A SERIES OF WEAK LOW PRESSURE CIRCULATIONS EXTEND ALONG
THE INTERNATIONAL BORDER WESTWARD OFF THE CALIFORNIA COAST.
LINGERING MOISTURE IN THE FORM OF 6-10 G/KG MIXING RATIOS HAVE
COMBINED WITH MODEST ASCENT THE PAST FEW DAYS RESULTING IN TERRAIN
DRIVEN THUNDERSTORMS AND NUMEROUS OUTFLOW BOUNDARIES. THE INFLUENCE
OF INCREASING WESTERLY FLOW ASSOCIATED WITH CONSOLIDATING LOW
PRESSURE OFF THE CALIFORNIA COAST OVER THE NEXT 48 HOURS WILL SLOWLY
ERODE BOUNDARY LAYER MOISTURE WHILE A MORE CONFLUENT, SUBSIDENT
REGIME ELIMINATES ASCENT MECHANISMS.
SUFFICIENT MOISTURE WILL LINGER ACROSS SOUTH-CENTRAL ARIZONA TODAY
ALLOWING TERRAIN INDUCED UPSLOPE TO SUPPORT SOME ISOLATED STORMS
DESPITE AN INCREASINGLY HOSTILE SYNOPTIC ENVIRONMENT. GIVEN THIS
UNDERLYING LACK OF SUPPORT, ANY STORMS SHOULD BECOME VERY SHORT
LIVED AND TIED TO THEIR INITIATION POINTS, HOWEVER DCAPE VALUES IN
EXCESS OF 1500 J/KG MAY SUPPORT SOME WELL DEFINED OUTFLOW BOUNDARIES
BEFORE SUBSIDENCE AND MLCIN OVERWHELMS FURTHER STORM FORMATION. BY
THURSDAY, ACTIVITY SHOULD BECOME RELEGATED TO THE WHITE MOUNTAINS OF
EASTERN ARIZONA, ONLY POTENTIALLY CLIPPING FAR EASTERN GILA COUNTY.
OTHERWISE, THE INCREASING WESTERLY FLOW AND INTRODUCTION OF JET
ENERGY WILL PROMOTE GUSTY AFTERNOON/EVENING WINDS, PARTICULARLY IN
THE TRADITIONAL DOWNSLOPE AREAS OF SOUTHEAST CALIFORNIA. THE CHANGE
IN THE PATTERN WILL ALSO ALLOW H5 HEIGHTS TO GRADUALLY FALL BELOW
588DM, AND FORECAST CONFIDENCE IS VERY GOOD THAT TEMPERATURES WILL
RETREAT SEVERAL DEGREES AND FALL MUCH CLOSER TO THE DAILY NORMALS
BY THURSDAY.
LONG TERM /FRIDAY THROUGH TUESDAY/
THERE IS EXCELLENT AGREEMENT AMONG ENSEMBLE MEMBERSHIP THAT MORE
PRONOUNCED EAST PACIFIC TROUGHING WILL EJECT INTO THE GREAT BASIN
RESULTING IN STRONG ZONAL FLOW ACROSS THE FORECAST AREA. THIS FLOW
PATTERN WILL COMPLETELY SCOUR AWAY MOISTURE SUCH THAT MIXING RATIOS
FALL CLOSER TO 2-3 G/KG ELIMINATING ALL CHANCES FOR PRECIPITATION.
WHILE H5 HEIGHTS WILL NOT DROP MARKEDLY, SUBTLE COOLING ALONG WITH
THE INTRODUCTION OF THIS MUCH DRIER AIRMASS WILL RESULT IN
TEMPERATURES FALLING TO NEAR NORMAL LEVELS OVER THE WEEKEND. THE
INITIAL ROUND OF MODEST HEIGHT FALLS COMBINED WITH SEASONABLY DEEP
MIXING DEPTHS WILL PROMOTE REPEATED CHANCES OF GUSTY AFTERNOON WINDS
LATE IN THE WEEK. JUXTAPOSED WITH THE INCOMING DRY AIRMASS AND
RECEPTIVE, DESSICATED FUELS, FIRE DANGER WILL BECOME QUITE ELEVATED.
ENSEMBLE SPREADS GROWS SOMEWHAT TOWARDS THE MIDDLE OF NEXT WEEK,
HOWEVER THE MAJORITY OF MEMBERS INDICATE BUILDING SUBTROPICAL
RIDGING OVER THE CWA AFTER THE TROUGH PASSAGE. H5 HEIGHTS SHOULD
REBOUND OVER 594DM WITH THE ANTI-CYCLONE CENTER BECOMING POSITIONED
DIRECTLY OVER ARIZONA. SOME OF THE MORE AGGRESSIVE MODELING IN THE
UPPER QUARTILE OF THE MODEL DISTRIBUTION EVEN SUGGESTS HEIGHTS
BREACHING 597DM BY THE MIDDLE OF THE WEEK WHICH WOULD EQUATE TO
LOWER ELEVATION TEMPERATURES REACHING 115F YIELDING EXPANSIVE MAJOR
HEATRISK.
AVIATION
UPDATED AT 1702Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
ANOTHER ROUGH OF GUSTY AFTERNOON WINDS WILL BE THE MAIN AVIATION
IMPACT THROUGH THE TAF PERIOD. WESTERLY WINDS WILL DOMINANT AGAIN
ACROSS THE METRO MID MORNING BEFORE BECOMING GUSTY DURING THE
AFTERNOON WITH GUSTS FREQUENTLY IN THE 20-25 KT RANGE. THIS
EVENING CAN EXPECT PERIODS OF SOUTHERLY WINDS TURNING NNE BY
TOMORROW MORNING. FEW MID TO HIGH CLOUDS WILL BE COMMON
THROUGHOUT THE PERIOD.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
THE MAIN AVIATION CONCERN WILL BE GUSTY WINDS THAT WILL CONTINUE
THROUGH THE AFTERNOON/EVENING UNDER GENERALLY CLEAR SKIES. AT
KIPL, WINDS WILL GENERALLY PREVAIL OUT OF THE WEST WHILE AT KBLH,
WINDS WILL FLUCTUATE OUT OF THE SOUTH TO SOUTHWEST. AFTERNOON/EARLY
EVENING GUSTS UPWARDS OF 25 KTS WILL BE COMMON AT KBLH AND
UPWARDS OF 25-30 KTS AT KIPL.
FIRE WEATHER
A PRONOUNCED DRYING TREND WILL SWEEP ACROSS THE REGION THE REMAINDER
OF THE WEEK WITH TERRAIN INDUCED SHOWERS/STORMS BECOMING COMPLETELY
ELIMINATED FROM THE FORECAST BY THE END OF THE WEEK. A FEW
THUNDERSTORMS MAY FORM OVER HIGHER TERRAIN FEATURES THIS AFTERNOON,
HOWEVER CHANCES OF WETTING RAINFALL WILL BE REMOTE WITH ONLY LIMITED
AREAS OF GUSTY OUTFLOW WINDS. DESPITE TEMPERATURES COOLING CLOSER TO
NORMAL LATER THIS WEEK, A MUCH DRIER AIRMASS WILL ALLOW MINIMUM
HUMIDITY LEVELS PRIMARILY IN A 10-20% RANGE TO DETERIORATE INTO
WIDESPREAD SINGLE DIGITS OVER THE WEEKEND AND EARLY NEXT WEEK.
CORRESPONDINGLY, OVERNIGHT RECOVERY WILL DETERIORATE INTO A POOR TO
FAIR 15-40% RANGE. WINDS WILL FREQUENTLY BECOME GUSTY THE REMAINDER
OF THE WEEK YIELDING A WIDESPREAD ELEVATED FIRE DANGER, HOWEVER AT
THIS TIME, SPEEDS APPEAR UNDER CRITICAL THRESHOLDS.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...18
LONG TERM...18
AVIATION...RYAN
FIRE WEATHER...18
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page