097
FXUS65 KPSR 041809
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1109 AM MST MON MAY 4 2026
UPDATE
18Z AVIATION DISCUSSION.
KEY MESSAGES
- MUCH COOLER TEMPERATURES WITH BELOW NORMAL READINGS WILL PREVAIL
DURING THE NEXT COUPLE OF DAYS.
- BREEZY TO LOCALLY WINDY CONDITIONS WILL BE COMMON THROUGH TUESDAY
WITH MODEST RAIN CHANCES ACROSS THE ARIZONA HIGH TERRAIN AREAS.
- A RAPID WARMING TREND TO ABOVE NORMAL TEMPERATURES IS LIKELY BY
THE LATTER HALF OF THE WEEK.
SHORT TERM /TODAY THROUGH TUESDAY/
THE LATEST WATER VAPOR SATELLITE IMAGERY AS WELL AS STREAMLINE
ANALYSIS SHOW A RATHER POTENT CUT-OFF LOW SITUATED JUST OFF THE
CENTRAL CA COAST WITH A LARGE STREAM OF MID TO HIGH-LEVEL CLOUDINESS
MOVING THROUGH THE DESERT SOUTHWEST. THE CUT-OFF LOW WILL CONTINUE
TO SLOWLY MIGRATE INLAND LATER TODAY THROUGH CENTRAL CA BEFORE
MOVING SOUTHEASTWARD THROUGH SOUTHERN CA AND AZ DURING THE DAY
TUESDAY AS AN OPEN WAVE. AS THE LOW CONTINUES TO SLOWLY APPROACH
THE REGION, 500 MB HEIGHT FIELDS WILL CONTINUE TO DECREASE INTO
THE 568-574DM RANGE AND COMBINED WITH THICK MID TO UPPER-LEVEL
CLOUDINESS, LIMITING THE SOLAR RADIATION, AFTERNOON HIGH
TEMPERATURES WILL BE A GOOD 10-15 DEGREES COOLER COMPARED TO
YESTERDAY AS READINGS ACROSS MOST OF THE LOWER DESERT COMMUNITIES
ONLY TOP OUT IN THE LOW 80S. THESE TEMPERATURES WILL BE A GOOD
5-10F BELOW NORMAL FOR EARLY MAY. THE ADDITIONAL HEIGHT FALLS AND
ENHANCED JET ENERGY WILL CONTINUE TO ENHANCE THE LOWER
TROPOSPHERIC WINDS. HOWEVER, THE THICKER CLOUD COVER MAY TEMPER
THE OVERALL MIXING DEPTH AND THUS THE ABILITY FOR THE HIGHER
MOMENTUM AIR TO FULLY MIX DOWN TO THE SURFACE. THUS, EVEN THOUGH
SOME GUSTY WINDS ARE LIKELY TO MATERIALIZE THIS AFTERNOON/EVENING,
IT WILL LIKELY NOT BE AS STRONG AS YESTERDAY WITH MANY AREAS
LIKELY OBSERVING GUSTS BETWEEN 20-30 MPH. SOME LOCALLY HIGHER
GUSTS IN EXCESS OF 30-35 MPH WILL ONCE AGAIN BE POSSIBLE ACROSS
WESTERN PORTIONS OF IMPERIAL COUNTY DUE TO MOUNTAIN ROTOR ACTION.
CANNOT RULE OUT TEMPORARY GUSTS EXCEEDING 40 MPH ACROSS THE WIND
PRONE AREAS OF SOUTHWESTERN IMPERIAL COUNTY.
AS THE LOW CONTINUES TO SLOWLY MIGRATE EASTWARD FROM THE EASTERN
PACIFIC, A PLUME OF SUBTROPICAL MOISTURE OUT AHEAD OF THE FEATURE
WILL BE ADVECTED INTO SOUTHERN AND EASTERN AZ LATER TODAY. THE
LATEST MODEL GUIDANCE HAS CONTINUED THE UPTREND IN MOISTURE LEVELS
AS PWATS ARE NOW SHOWN TO PEAK TO BETWEEN 0.8-1.0". THIS MOISTURE
COMBINED WITH THE LARGE FORCING FOR ASCENT FROM THE LOW WILL
RESULT IN AN AREA OF LIGHT SHOWERS TO BREAK OUT THIS EVENING
THROUGH THE OVERNIGHT PERIOD ACROSS PORTIONS OF SOUTHEAST AZ
AS WELL AS ACROSS THE FOOTHILLS AND THE HIGHER TERRAIN AREAS TO
SOUTH AND EAST OF PHOENIX AS DEPICTED BY THE LATEST HI-RES
GUIDANCE. IT IS NOT INCONCEIVABLE TO EVEN SEE SOME RAIN DROPS
MAKING IT TO THE SURFACE ACROSS THE GREATER PHOENIX AREA. ACTIVITY
WILL CONTINUE TO AFFECT THE HIGHER TERRAIN AREAS TO THE NORTH AND
EAST OF PHOENIX INTO THE FIRST PART OF TUESDAY. OVERALL RAINFALL
AMOUNTS SHOULD REMAIN ON THE LIGHT SIDE, WITH MOST AREAS OBSERVING
LESS 0.10". OTHERWISE, AS THE COLD CORE MOVES DIRECTLY OVERHEAD
ON TUESDAY AFTERNOON, HIGH TEMPERATURES ACROSS MOST OF THE LOWER
DESERT COMMUNITIES WILL STRUGGLE TO REACH 80 DEGREES WITH MANY
AREAS TOPPING OUT IN THE UPPER 70S, WHICH WILL BE A SOLID 10-15F
BELOW NORMAL.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
THE PRIMARY ENERGY FROM THE LOW WILL EXIT TO THE NORTHEAST AND GET
ABSORBED BY ANOTHER BROAD TROUGH ENCOMPASSING MOST OF THE CENTRAL
AND EASTERN CONUS ON WEDNESDAY. MEANWHILE, A TRAILING PIECE OF
ENERGY WILL DEVELOP INTO A WEAK CUT-OFF LOW JUST SOUTH OF THE
INTERNATIONAL BORDER IN NORTHERN SONORA AS AN UPPER-LEVEL RIDGE OF
HIGH PRESSURE BUILDS ALONG THE WEST COAST. ALTHOUGH THERE
CONTINUES TO SOME UNCERTAINTY WITH RESPECT TO THE SPEED
PROGRESSION OF THIS FEATURE AS IT CUTS OFF FROM THE MAIN JET
STREAM ENERGY, LATEST TRENDS HAS BEEN FOR A FASTER EASTWARD
PROGRESSION THROUGH THE LATTER HALF OF NEXT WEEK WITH NO SENSIBLE
WEATHER IMPACTS EXPECTED FOR OUR REGION.
OTHERWISE, THE MAIN WEATHER STORY HEADING TOWARDS THE END OF THE
WEEK AND BEYOND WILL BE THE RISING TEMPERATURES WITH AN EXTENDED
STRETCH OF TRIPLE DIGIT HIGHS. AS THE UPPER-LEVEL RIDGE GRADUALLY
BUILDS ACROSS THE WESTERN CONUS BY THE LATTER HALF OF THE WEEK,
TEMPERATURES WILL BE ON A RAPID WARMING TREND WITH HIGHS BACK UP
IN THE 90S ON THURSDAY AND INTO TRIPLE DIGITS AS EARLY AS FRIDAY
AND BEYOND. AS AFTERNOON HIGHS CLIMB INTO THE TRIPLE DIGITS, THE
OVERALL HEATRISK LEVEL ACROSS MOST OF THE AREA WILL INCREASE INTO
THE MODERATE CATEGORY.
AVIATION
UPDATED AT 1750Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
THE MAIN AVIATION CONCERNS FOR THIS FORECAST PERIOD WILL BE
POTENTIAL REDUCTIONS IN SLANTWISE VSBY DUE TO WILDFIRE SMOKE AS
WELL AS LOWER CIGS WHICH ARE PROGGED TO ARRIVE TUESDAY MORNING.
WIND WILL BECOME ELEVATED OUT OF THE W-SW THROUGH THIS AFTERNOON
WITH INTERMITTENT GUSTS UP TO 20 KTS EXPECTED INTO THE EVENING
HOURS. NO DIURNAL EASTERLY SHIFT IS ANTICIPATED TONIGHT WITH WINDS
CONTINUING OUT OF THE SW. SHOWERS AND PERHAPS AN ISOLATED
THUNDERSTORM WILL BE POSSIBLE LATE TONIGHT INTO TUESDAY MORNING,
AND THUS VCSH HAS BEEN ADDED AT ALL TERMINALS STARTING AROUND 05Z
AT KIWA AND 07Z AT KPHX. CEILINGS WILL GRADUAL LOWER THROUGH
TONIGHT AS A WEATHER SYSTEM MOVES INTO THE REGION. CLOUD BASES
WILL FALL TO AROUND 5 KFT AT KPHX EARLY TUESDAY MORNING AND AS LOW
AS 3.5 KFT AT THE OTHER METRO TERMINALS.
SLANTWISE VIS/HAZY CONDITIONS WILL LIKELY CONTINUE TO BE A
CONCERN DUE TO THE BRUSH FIRE IN BUCKEYE. UPPER LEVEL WINDS
PREVAIL OUT OF THE W-SW, SO OPERATIONAL IMPACTS, MAINLY AT KSDL
AND KDVT CANNOT BE RULED OUT.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
PERIODS OF GUSTY W-SW WINDS WILL CONTINUE BE THE MAIN AVIATION
CONCERN DURING THE NEXT 24 HOURS. AT KIPL, GUSTS BETWEEN 25-35 KTS
ARE EXPECTED TO CONTINUE THROUGHOUT THE TAF PERIOD WITH SUSTAINED
WIND SPEEDS BETWEEN 15-25 KTS, OUT OF THE WEST. WITH THESE WINDS,
BLOWING/LOFTED DUST AROUND THE KIPL TERMINAL MAY BE POSSIBLE,
LEADING TO CONCERNS OF REDUCED SURFACE AND SLANTWISE VIS. AT BLH,
EXPECT GUSTS IN THE 20-25 KT RANGE DEVELOPING THIS AFTERNOON AND
PERSISTING INTO THE EARLY EVENING. SCT-BKN HIGH CLOUDS WILL BE
COMMON THROUGH MOST OF THE PERIOD.
FIRE WEATHER
SOME GUSTY WINDS WILL CONTINUE TO REMAIN THREAT THROUGH TUESDAY AS
AN AREA OF LOW PRESSURE APPROACHES AND MOVES THROUGH THE REGION,
WITH ONLY A LOCALLY ELEVATED FIRE DANGER THREAT EXPECTED AS HIGHER
HUMIDITIES WILL LIMIT A GREATER RISK. SOME MODEST RAIN CHANCES
WILL BE IN PLACE, MAINLY ACROSS THE FAR EASTERN DISTRICTS, LATE
TODAY THROUGH TUESDAY MORNING WITH THE CHANCES FOR WETTING RAINS
REMAINING ON THE LOW SIDE. AFTERNOON MINRHS BETWEEN 15-25% WILL BE
COMMON TODAY BEFORE INCREASING INTO A 20-35% RANGE TUESDAY ALONG
WITH GOOD OVERNIGHT RECOVERIES. LIGHTER WINDS AS WELL AS MUCH
WARMER TEMPERATURES AND LOWER HUMIDITIES ARE THEN FORECAST FOR THE
LATTER HALF OF THE WEEK.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...LOJERO
LONG TERM...LOJERO
AVIATION...SALERNO
FIRE WEATHER...LOJERO
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page