596
FXUS65 KPSR 170517
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1017 PM MST TUE JUN 16 2026
UPDATE...UPDATED 06Z AVIATION DISCUSSION
KEY MESSAGES
- TEMPERATURES WILL CONTINUE TO HOVER 5 TO 8 DEGREES ABOVE NORMAL
THROUGH THE MIDDLE OF THE WEEK WHICH WILL RESULT IN PERSISTENT,
WIDESPREAD MODERATE, TO LOCALLY MAJOR, HEATRISK.
- LINGERING MOISTURE WILL RESULT IN VERY ISOLATED SHOWER AND
THUNDERSTORM CHANCES TODAY, MAINLY AROUND ENHANCED TERRAIN
FEATURES IN SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA.
- AN EASTERN PACIFIC LOW WILL HELP DRY THE REGION OUT, LIMITING
FURTHER RAIN CHANCES, WHILE ALSO PROVIDING NEAR NORMAL
TEMPERATURES AND BREEZY CONDITIONS BY THE END OF THE WEEK AND
INTO THE WEEKEND.
SHORT TERM /TODAY THROUGH WEDNESDAY/
LATEST MID-LVL WV IMAGERY AND 500 MB STREAMLINE ANALYSIS REVEALS AN
AREA OF HIGH PRESSURE SITUATED OVER THE BAJA DEL NORTE WHILE A WEAK
LOW PRESSURE SYSTEM MEANDERS OVER THE EASTERN PACIFIC, SEVERAL
HUNDRED MILES OFF THE CALIFORNIA COAST. THE UPPER-LVL FLOW IS VERY
WEAK AND CHAOTIC OVER OUR FORECAST AREA TODAY, BUT THERE IS JUST
ENOUGH DIFFLUENCE ALOFT AND RESIDUAL SFC MOISTURE IN PLACE TO HELP
GENERATE ISOLATED SHOWERS AND STORMS OVER THE HIGH TERRAIN FEATURES
OF NORTHERN AND WESTERN AZ. THE MOST LIKELY LOCATION FOR STORMS TO
DEVELOP TODAY WILL BE OVER THE KOFA AND CHOCOLATE MOUNTAINS. DUE TO
THE WEAK UPPER LVL FLOW, ANY STORM THAT DEVELOPS WILL NOT MOVE MUCH
AT ALL AND SHOULD REMAIN CONFINED GENERALLY TO ANY TERRAIN FEATURES.
THE MAIN THREATS WITH ANY STORMS THIS AFTERNOON WILL BE STRONG
OUTFLOW WINDS AND POTENTIAL FOR BLOWING DUST, ESPECIALLY ALONG THE
I-10 AND I-8 CORRIDORS IN WESTERN AZ AND SOUTHEAST CA. UNDER THE
INFLUENCE OF RIDGING AND POSITIVE HGHT ANOMALIES, TEMPERATURES
WILL SOAR INTO THE 105-111 DEGREE RANGE THIS AFTERNOON WITH SOME
OF THE LOWEST ELEVATIONS AND RIVER VALLEYS APPROACHING 112-113
DEGREES. THESE HIGH TEMPERATURES ARE AROUND 5 TO 8 DEGREES ABOVE
NORMAL FOR MID-JUNE AND WILL RESULT IN A LOCALIZED MAJOR HEATRISK.
THEREFORE, PROPER HEAT PRECAUTIONS SHOULD BE USED IF WORKING
OUTSIDE FOR A PROLONGED PERIOD.
ON WEDNESDAY, THE AFOREMENTIONED AREA OF LOW PRESSURE OFF THE
COAST OF CALIFORNIA WILL BEGIN TO PROGRESS INLAND AND WILL RESULT
IN DRIER AIR BUILDING INTO THE REGION FROM W TO E. ALTHOUGH PWATS
WILL FALL BELOW AN INCH ACROSS THE WESTERN DESERTS, THEY WILL
STILL BE AROUND 150-175% OF NORMAL ACROSS SOUTH-CENTRAL AZ ON
WEDNESDAY AFTERNOON. THUS, ANOTHER ROUND OF ISOLATED TO WIDELY
SCATTERED CONVECTION WILL BE POSSIBLE OVER THE TYPICAL TERRAIN
FEATURES SURROUNDING THE LOWER DESERTS. STEERING FLOW WILL BE MORE
OUT OF THE S-SW ON WEDNESDAY WHICH WILL KEEP CONVECTION FROM
MOVING TOWARD THE PHOENIX METRO, HOWEVER RESIDUAL OUTFLOW
BOUNDARIES FROM DECAYING CONVECTION COULD STILL REACH N PINAL OR S
GILA COUNTIES. ANOTHER RESULT OF THE UPPER-LV LOW MOVING INTO SE
CALIFORNIA ON WEDNESDAY AFTERNOON WILL BE AN UPTICK IN BREEZINESS
WHERE GUSTS COULD REACH 25-35 MPH ALONG AND WEST OF THE COLORADO
RIVER VALLEY. STRONGER WINDS IN THE 850-700 MB LEVEL WILL ALSO
RESULT IN LOCALIZED GUSTS AROUND 40 MPH AT MOUNTAIN PEAK LEVEL,
ESPECIALLY IN SW IMPERIAL COUNTY. 500 MB HGHTS WILL BEGIN TO
DECREASE SLIGHTLY ON WEDNESDAY, HOWEVER HIGHS ACROSS THE LOWER
DESERTS WILL STILL REACH UPWARDS OF 105-111 DEGREES RESULTING IN
AT LEAST ONE MORE AFTERNOON WITH A LOCALIZED MAJOR HEATRISK.
LONG TERM /THURSDAY THROUGH MONDAY/
THE REMAINDER OF THE WEEK LOOKS GENERALLY UNEXCITING, AT LEAST FOR
OUR AREA, AS RAIN CHANCES FALL TO NEAR ZERO ONCE CONSIDERABLE DRYING
TAKES PLACE. THERE COULD BE JUST ENOUGH LEFT OVER MOISTURE TO
SQUEEZE OUT SOME SHOWERS OVER THE WHITE MOUNTAINS ON THURSDAY, BUT
THAT LOOKS TO BE THE ONLY REMAINING PRECIP POTENTIAL STATEWIDE
THROUGH AT LEAST THE START OF NEXT WEEK. THIS DROP IN REGIONAL
MOISTURE WILL BE THANKS TO THE MIGRATION OF AN EASTERN PACIFIC
TROUGH TOWARD THE GREAT BASIN, IMPARTING DRY SOUTHWESTERLY FLOW UPON
THE REGION. WE MAY LOSE THE MOISTURE, BUT THERE IS SOME GOOD NEWS.
THIS WAVE WILL ERODE AT POSITIVE HEIGHT ANOMALIES, WHICH WILL AID IN
A DOWNTREND IN TEMPERATURES WITH READINGS FALLING TOWARD SEASONAL
LEVELS. NOW, THIS DOES NOT MEAN WE GET A BREAK FROM THE TRIPLE
DIGITS, BUT AT LEAST DAILY FORECASTED HIGHS FALL CLOSER TO 100-108.
NOT A MASSIVE AMOUNT OF RELIEF, BUT ENOUGH TO TAMP HEATRISK DOWN TO
THE LOWER END OF THE MODERATE CATEGORY. HEAT PRECAUTIONS WILL STILL
NEED TO REMAIN IN PLACE REGARDLESS. LOWER MOISTURE WITH THOSE COOLER
TEMPS WILL ALSO ALLOW FOR SOME MORE COMFORTABLE OVERNIGHT LOWS IN
THE UPPER 60S TO NEAR 80 DEGREES. SOMETHING THAT WILL HAVE TO
MONITORED IS THE POTENTIAL FOR ELEVATED FIRE WEATHER CONDITIONS AS
THIS FEATURE WILL INCREASE WINDS REGIONWIDE. EXACT STRENGTH OF GUSTS
IS STILL UNCERTAIN AT THIS TIME, BUT WITH VERY DRY AIR EXPECTED TO
BE IN PLACE, IT WOULD NOT TAKE MUCH WIND TO INCREASE FIRE DANGER.
AVIATION
UPDATED AT 0515Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
GUSTY WINDS WEDNESDAY AFTERNOON/EARLY EVENING WILL BE THE MAIN
AVIATION WEATHER ISSUE THROUGHOUT THE TAF PERIOD. WESTERLY WINDS
WILL PREVAIL THROUGH THE FIRST PART OF THE OVERNIGHT PERIOD, WITH
UNCERTAINTY OF WIND DIRECTIONS EARLY WEDNESDAY MORNING AS THERE IS
POTENTIAL THAT THE TRADITIONAL EASTERLY SHIFT DOES NOT TAKE PLACE,
ESPECIALLY AT KPHX, WITH LIGHT AND VARIABLE DIRECTIONS POSSIBLE.
OTHERWISE, WESTERLY WINDS WILL PREVAIL FROM THE MID-MORNING HOURS
ONWARDS WITH AFTERNOON/EARLY EVENING GUSTS FREQUENTLY IN THE 20-25
KT RANGE. FEW MID TO HIGH CLOUDS WILL BE COMMON THROUGHOUT THE
PERIOD.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
GUSTY WINDS WEDNESDAY AFTERNOON/EVENING UNDER GENERALLY CLEAR
SKIES WILL BE THE MAIN AVIATION WEATHER ISSUE THROUGHOUT THE TAF
PERIOD. 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
LINGERING MOISTURE WILL HELP KEEP ISOLATED THUNDERSTORMS IN THE
FOREAST MAINLY OVER THE HIGH TERRAIN FEATURES OF SOUTHWEST ARIZONA
AND SOUTHEAST CALIFORNIA TODAY AND SOUTH-CENTRAL AZ ON WEDNESDAY,
HOWEVER CHANCES OF ANY WETTING RAINFALL REMAIN LOW. THE MAIN
CONCERNS WITH ANY STORMS THAT DO DEVELOP WILL BE DRY LIGHTNING AND
STRONG, GUSTY OUTFLOW WINDS. OUTSIDE OF ANY STORMS, WINDS WILL
FOLLOW DIURNAL TRENDS WILL WITH BREEZY TO LOCALLY WINDY CONDITIONS
DEVELOPING WEDNESDAY AFTERNOON, MAINLY FOR THE LOWER COLORADO AND
IMPERIAL VALLEYS, ALONG WITH THE HIGH TERRAIN OF ARIZONA. BREEZY
CONDITIONS WILL LIKELY PERSIST THROUGH THIS WEEKEND. ALONG WITH
INCREASING WINDS, MINRHS WILL FALL FROM 10-15% TOWARD 5-10% BY
MID- WEEK, GENERATING DAILY WIDESPREAD ELEVATED TO LOCALLY NEAR
CRITICAL, FIRE WEATHER CONDITIONS. MAXRHS WILL OFFER LESS AND LESS
RELIEF OVER IN THE COMING DAYS AS VALUES FALL FROM 30-50% TOWARD
15-35%.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...SALERNO
LONG TERM...RW
AVIATION...LOJERO
FIRE WEATHER...RW/SALERNO
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