293
FXUS65 KPSR 162031
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
130 PM MST THU JUL 16 2026
KEY MESSAGES
- TEMPERATURES WILL COOL ACROSS MUCH OF ARIZONA DROPPING TO BELOW
NORMAL LEVELS WHILE SOUTHEAST CALIFORNIA MAINTAINS NEAR NORMAL
READINGS.
- SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD ACROSS
EASTERN AND CENTRAL ARIZONA THROUGH FRIDAY WITH THE POTENTIAL FOR
HEAVY RAINFALL AND LOCALIZED FLASH FLOODING.
- A DECREASE IN THUNDERSTORM COVERAGE ACROSS LOWER ELEVATIONS WILL
ARRIVE THIS WEEKEND WITH THE BETTER CHANCES FAVORING ARIZONA HIGH
TERRAIN LOCATIONS.
SHORT TERM /TODAY THROUGH FRIDAY/
EARLY AFTERNOON SATELLITE IMAGERY DEPICTS SEVERAL SMALL MCVS
TRAVERSING THE REGION ADDING ASCENT TO AN ALREADY FAVORABLE
UNDERLYING SYNOPTIC PATTERN OF STRONG DIVERGENCE ALOFT ATOP
DEEPENING MOISTURE PROFILES. IN FACT, 12-15 G/KG LOW LEVEL MIXING
RATIOS HAVE SPREAD ACROSS MUCH OF THE CWA SUPPORTING SCATTERED
SHOWERS AHEAD OF MANY OF THESE VORTICITY FEATURES. ON THE OTHER
HAND, THIS THICKER MOISTURE HAS NEGATIVELY AFFECTED INSOLATION OVER
MUCH OF THE REGION YIELDING LIMITED INSTABILITY WITH NOTABLE
INHIBITION STILL PRESENT. THIS EVOLUTION HAS ADDED COMPLEXITY AND
GREATER UNCERTAINTY TO THE FORECAST OVER THE NEXT 36-48 HOURS AS
MOST MODELING SYSTEMS HAVE NOT FULLY CAPTURED THE EXTENT OF CLOUD
COVER AND ONGOING SHOWERS. ONE CONSEQUENCE OF THIS ALLOWS FOR THE
CANCELLATION OF THE EXTREME HEAT WARNING OVER THE WESTERN CWA AS
CLOUDS AND RAIN HAVE NEGATED INTENSE HEATING AND ASSOCIATED HEAT
IMPACTS.
DESPITE ALL THE CONVECTIVELY DETRIMENTAL FEATURES ACROSS THE LOCAL
FORECAST AREA, THERE ARE A FEW REGIONAL FEATURES WHICH COULD
EVENTUALLY ENCOURAGE STORMS OVER SOUTH-CENTRAL ARIZONA TONIGHT INTO
FRIDAY MORNING. INTENSE ASCENT BETWEEN 2 WELL DEFINED EASTERLY WAVES
(ONE OVER CENTRAL BAJA AND THE OTHER OVER WEST TEXAS) FEEDING ON
1500+ J/KG MLCAPE ACROSS NORTHEAST SONORA HAS FOSTERED EXPLOSIVE
CONVECTIVE DEVELOPMENT WITH EVIDENCE OF A CONGEALING MCS ALREADY
THIS AFTERNOON. HIGH RESOLUTION MODELING CAPTURING THIS COMPLEX
SUGGESTS OUTFLOW AND VORTICITY ADVECTION FORCING NEW DEVELOPMENT
OVER SOUTHERN ARIZONA BY EARLY EVENING. WHILE OUTFLOW WILL NOT BE AS
STRONG AS PREVIOUS DAYS, THE COMBINED EFFECT WITH SYNOPTIC ENERGY
IMPORTATION MAY BRING ACTIVITY TOWARDS THE PHOENIX METRO LATE
EVENING. CONCURRENTLY, A SHORTWAVE NEAR THE FOUR CORNERS CAPTURED IN
NE FLOW WAS TAPPING AN UNSTABLE AIRMASS OVER NORTHERN ARIZONA, AND
ALSO HEADING TOWARDS SOUTH-CENTRAL ARIZONA TONIGHT.
AS A RESULT, THERE IS GROWING EVIDENCE THAT MULTIPLE MCVS AND PLUME
OF HIGHER THETA-E CONGEAL SOMEWHERE AROUND PINAL/EASTERN MARICOPA
COUNTIES OVERNIGHT AS DISCUSSED IN AN ALTERNATIVE FORECAST OUTCOME
YESTERDAY. WHILE MLCAPE/DCAPE WILL BE SUBSTANTIALLY LOWER DURING THE
OVERNIGHT, MUCAPE AROUND 500-750 J/KG WILL STILL BE PRESENT ALBEIT
WITH DETERIORATING MIDLEVEL LAPSE RATES. NEVERTHELESS, AS MIXING
RATIOS REACH 15 G/KG AND TOTAL COLUMN PWATS EXCEED 2.00", ANY AMOUNT
OF FOCUSED ASCENT SHOULD SUFFICIENT FOR SCATTERED SHOWERS AND
THUNDERSTORMS. VERY EFFICIENT RAINFALL RATES WITH THE POTENTIAL FOR
WARM RAIN PROCESSES COULD YIELD AT LEAST 2-3"/HR GIVEN THE MOISTURE
PROFILES, AND THIS SCENARIO MATCHES MANY HISTORICAL LATE NIGHT/EARLY
MORNING EVENTS THAT HAVE PRODUCED SIGNIFICANT FLOODING AROUND THE
PHOENIX METRO. THE CURRENT FLOOD WATCH MAY NEED LOCAL EXTENSIONS
THROUGH FRIDAY MORNING ONCE AREA OF STORMS BECOME ESTABLISHED
OVERNIGHT. OTHERWISE, DEEP CONVECTION SHOULD EVENTUALLY EXHAUST
ELEVATED INSTABILITY BY FRIDAY AFTERNOON AS ATMOSPHERIC PROFILES
BECOME MOIST ADIABATIC. WHILE A FEW LINGERING SHOWERS MAY PERSIST
THROUGH THE AFTERNOON, THERE IS VERY LITTLE EVIDENCE OF RENEWED
CONVECTION DURING THE AFTERNOON/EVENING GIVEN THE EXPECTED EXPANSIVE
THICK CLOUD COVER LEFT OVER FROM THE MORNING ACTIVITY.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
ALTHOUGH SOME UNCERTAINTY REMAINS, GUIDANCE CONTINUES TO TREND DRIER
FOR THIS WEEKEND, PARTICULARLY THE GEFS. THIS DRIER AIR IS EXPECTED
TO ADVECT IN FROM THE SOUTH SOUTHWEST STARTING FRIDAY MORNING AND
CONTINUE THROUGH MOST OF SATURDAY, LOWERING PWATS TO AS LOW AS 1.4-
1.5", BUT THE EURO MAINTAINS A MORE OPTIMISTIC 1.7-1.9". THE
EASTERLY WAVE IS ALSO FORECAST TO WEAKEN WHILE IT BRIEFLY SHIFTS
BACK TOWARD CENTRAL TEXAS. THE COMBINATION OF THE EXPECTED DRYING,
VERY LITTLE INSTABILITY, AND WEAKER UPPER LEVEL SUPPORT IS LIKELY TO
LIMIT SHOWER AND THUNDERSTORM POTENTIAL ON SATURDAY. AS OF NOW, MUCH
OF THE LOWER DESERTS SHOULD STAY QUIET ON SATURDAY, WHILE SCATTERED
SHOWERS AND STORMS ARE MUCH MORE LIKELY OVER THE ARIZONA HIGH
TERRAIN. TEMPERATURES WILL BEGIN TO RECOVER STARTING SATURDAY, BUT
DAYTIME HIGHS ARE STILL LIKELY TO FALL SHORT OF 100 DEGREES IN THE
PHOENIX AREA.
STARTING SUNDAY INTO EARLY NEXT WEEK, THE SUBTROPICAL RIDGE IS
LIKELY TO BECOME MORE ELONGATED FROM THE GREAT BASIN TO THE LOWER MS
RIVER VALLEY. THE REMNANTS OF THE EASTERLY WAVE OR EVEN A NEWLY
DEVELOPED DISTURBANCE MAY ALSO BECOME MORE OF A PLAYER FOR MONSOON
ACTIVITY BY AROUND MONDAY OR TUESDAY AS MOISTURE REMAINS PLENTY
ADEQUATE FOR CONVECTION. AN INCREASE IN EASTERLY UPPER LEVEL WINDS
ACROSS TEXAS MAY EVENTUALLY STRETCH INTO THE DESERT SOUTHWEST BY
LATE MONDAY INTO TUESDAY WHICH COULD HELP DRIVE MONSOON ACTIVITY
THROUGHOUT PORTIONS OF THE LOWER DESERTS AGAIN. NBM POPS STILL FAVOR
THE ARIZONA HIGH TERRAIN THROUGH THE PERIOD, BUT IT SEEMS LIKELY THE
LOWER DESERTS WILL SEE ANOTHER DAY OR TWO OF ACTIVE WEATHER.
FORECAST TEMPERATURES FOR NEXT WEEK SHOW A GRADUAL UPWARD TREND,
DESPITE FAIRLY HIGH MODEL SPREAD. LOWER DESERT DAYTIME HIGHS MAY
AGAIN REACH 100 DEGREES IN THE PHOENIX AREA BY MONDAY AND EVENTUALLY
BACK TO NEAR NORMAL DURING THE LATTER HALF OF NEXT WEEK. LOCATIONS
ACROSS SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA ARE LIKELY TO
MAINTAIN NEAR NORMAL TEMPERATURES THROUGHOUT NEXT WEEK.
AVIATION
UPDATED AT 1746Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
THE MAIN AVIATION CONCERN WILL BE AN EXTENDED PERIOD OF ERRATIC
WINDS AND VCTS/TSRA IMPACTS THIS EVENING THROUGH TONIGHT. THERE IS
ALREADY SOME DEVELOPMENT OF LIGHT SHOWERS WEST OF THE TERMINALS,
HOWEVER MOVING TO THE SW AWAY FROM THE TERMINALS AND FURTHER
DEVELOPMENT OVER THE NEXT SEVERAL HOURS SHOULD STAY OUTSIDE OF THE
TERMINALS RANGE. STORMS LATER THIS AFTERNOON ARE FORECAST TO FOCUS
INITIALLY TO THE NORTH AND THEN TO THE SOUTH AND SOUTHEAST, WHICH
MAY LEAD TO PROMINENT OUTFLOWS FROM BOTH DIRECTIONS, WITH A
NORTHERLY OUTFLOW FAVORED FIRST IN THE LATE AFTERNOON. THERE ARE
GOOD CHANCES (40-60%) FOR VCTS/TSRA & VCSH/SHRA AT TERMINALS HEADING
INTO THE LATE EVENING AND OVERNIGHT HOURS TONIGHT. TOTAL
ACCUMULATION OVER THE TAF PERIOD IS EXPECTED TO BE MOSTLY BETWEEN
0.25"-0.75" HOWEVER SOME STORMS MAY PRODUCE LOCALIZED VERY HEAVY,
BLINDING, RAINFALL, WHETHER THE TERMINALS WILL BE IMPACTED OR NOT
WILL DEPEND ON THE LOCATION OF THESE ISOLATED HEAVIER STORMS. CLOUD
BASES WILL MOSTLY STAY AT OR ABOVE 8-10K FT AGL, BUT THERE IS
POTENTIAL FOR LOWER CLOUD BASES, DOWN TO 6-7K FT AGL. THE DUST
POTENTIAL IS LOW.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR AVIATION CONCERNS ARE EXPECTED DURING THE NEXT 24 HOURS
UNDER INCREASING MIDLEVEL CLOUDS. SE WINDS WILL BE COMMON AT KIPL,
WITH SPEEDS AOA 10KTS THROUGH THE FIRST PORTION OF THE TAF THEN
WEAKENING LATER THIS EVENING/TONIGHT. SOUTHERLY WINDS WILL PREVAIL
AT KBLH. A PERIOD OF GUSTS AROUND 20-25 KT MAY DEVELOP AT KBLH LATE
THIS MORNING THROUGH THE AFTERNOON/EARLY EVENING. THERE IS LOW
POTENTIAL (10-20%) FOR AN ISOLATED SHOWER OR STORM THIS AFTERNOON
AND EVENING, CONDITIONAL ON THE EVOLUTION OF DISTURBANCES TO THE
EAST OF THE AREA.
FIRE WEATHER
ACTIVE MONSOON WEATHER WITH ELEVATED MOISTURE LEVELS WILL CONTINUE
THROUGH THE REST OF THE WEEK. SHOWER AND THUNDERSTORM CHANCES WILL
INCREASE OVER THE EASTERN DISTRICTS TODAY WITH ONLY ISOLATED CHANCES
OVER THE WESTERN DISTRICTS. LOCALIZED HEAVY RAINFALL IS EXPECTED
TODAY INTO EARLY FRIDAY ACROSS THE EASTERN DISTRICTS WITH SOME
POTENTIAL FOR GUSTY OUTFLOW WINDS LATE THIS AFTERNOON AND EARLY
EVENING. MINRHS WILL BE 35-55% FOR THE EASTERN DISTRICTS THROUGH
SATURDAY TO 20-35% ACROSS THE WESTERN DISTRICTS. OUTSIDE OF
POTENTIAL THUNDERSTORM OUTFLOWS, WINDS FOR THE EASTERN DISTRICTS
WILL TEND TO BE LIGHT AND SOMEWHAT FAVOR DIURNAL TRENDS. WINDS WILL
PREDOMINATELY FAVOR THE SOUTH AND BE BREEZY AT TIMES ACROSS THE
WESTERN DISTRICTS.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...FLOOD WATCH THROUGH LATE TONIGHT FOR AZZ534-537>563.
CA...NONE.
SHORT TERM...18
LONG TERM...KUHLMAN
AVIATION...RYAN
FIRE WEATHER...KUHLMAN
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