815
FXUS65 KPSR 132037
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
137 PM MST MON JUL 13 2026
UPDATE
18Z AVIATION DISCUSSION.
KEY MESSAGES
- A FAIRLY TYPICAL MONSOON PATTERN WILL CONTINUE THROUGH THE
FIRST HALF OF THE WEEK, WITH EARLY AFTERNOON SHOWERS AND
THUNDERSTORMS FORMING OVER THE ARIZONA HIGH TERRAIN DAILY
FOLLOWED BY CHANCES OVER THE LOWER DESERTS FOCUSED LATER IN THE
AFTERNOON INTO THE EVENING.
- A DISTURBANCE MAY APPROACH THE REGION FROM THE EAST DURING THE
LATTER HALF OF THE WEEK, BRINGING FAVORABLE CONDITIONS FOR MORE
WIDESPREAD SHOWERS AND THUNDERSTORMS.
- SEASONABLY HOT TEMPERATURES WILL PERSIST THROUGH THE MIDDLE OF
THE WEEK RESULTING IN WIDESPREAD MODERATE HEAT RISK AND LOCALLY
MAJOR HEAT RISK ON WEDNESDAY IN SOUTHEAST CALIFORNIA, FOLLOWED
BY COOLER TEMPERATURES LATE WEEK.
SHORT TERM /TODAY THROUGH TUESDAY/
AS OF 1:13 AM MST THIS MORNING PHOENIX SKY HARBOR WAS ABLE TO
MEASURE WITH A TOTAL OF 0.01", THE FIRST MEASURABLE RAINFALL SINCE
MARCH 29TH, 2026. MANY SURROUNDING AREAS IN THE PHOENIX METRO WERE
ALSO ABLE TO MEASURE BETWEEN 0.01"-0.05" WHILE AREAS IN SOUTHERN
MARICOPA COUNTY, PINAL COUNTY AND THE HIGHER TERRAINS RECEIVED
MEASUREMENTS BETWEEN 0.25"-0.75" TO LOCALLY HIGHER AMOUNTS. THIS WAS
DUE TO A CLUSTER OF SEVERE THUNDERSTORMS THAT DEVELOPED IN SOUTHERN
MARICOPA COUNTY AND PINAL COUNTY YESTERDAY EVENING. WHILE
MEASURABLE RAINFALL IS ALWAYS EXCITING, ESPECIALLY HERE IN THE
LOWER DESERTS, THAT WAS NOT THE HIGHLIGHT OF YESTERDAYS ACTIVITY AS
THOSE AREAS, AND EVEN INTO THE WEST VALLEY, RECEIVED THEIR FIRST
DUST STORM WARNING SINCE SEPTEMBER 26TH, 2025. THE STORMS THAT
DEVELOPED WERE ABLE TO PRODUCE SOUTHEASTERLY GUSTS UP TO 45-50 MPH
AT TIMES, PICKING UP A LARGE AMOUNT OF DUST AND REDUCING
VISIBILITIES TO UNDER 1/4 OF A MILE TO NEAR ZERO IN SOME AREAS LAST
NIGHT.
TODAY GOES MID-LEVEL WV IMAGERY SHOWS THE HIGH PRESSURE OVER THE
NORTHERN PLAINS ASSOCIATED WITH A LARGE AREA OF DRY AIR. THE
POSITION OF THIS HIGH PRESSURE IS WHAT HAS SHIFTED FLOW ALOFT OVER
THE DESERT SW OUT OF THE SOUTHEAST, AND ALLOWING FOR GOOD MOISTURE
ADVECTION. THIS INCREASE IN MOISTURE HAS LEAD TO PWATS BETWEEN 1.5"-
1.8" ACROSS A VAST MAJORITY OF THE CWA WITH LOCALLY HIGHER, CLOSER
TO 2", NEAR THE GULF OF CALIFORNIA. THIS MOISTURE IS EXPECTED TO
LINGER THROUGHOUT THE WEEK WITH 1000MB-700MB MIXING RATIOS STAYING
GENERALLY BETWEEN 9-13 G/KG ACROSS THE REGION. WITH YESTERDAY'S
ACTIVITY THE ATMOSPHERE IS SLIGHTLY WORKED OVER RESULTING IN CHANCES
TODAY FOR ACTIVITY TO BE LOWER, HOWEVER NOT ZERO, WITH POPS BETWEEN
15-25% IN THE METRO, AND BETWEEN 30-50% IN THE FOOTHILLS. THE LATEST
HRRR RUN DOES SHOW ANOTHER ROUND OF STORMS DEVELOPING TODAY IN MUCH
OF THE SAME AREAS AS YESTERDAY (EASTERN HIGH TERRAIN AND SOUTH
CENTRAL AZ), HOWEVER WINDS ARE EXPECTED TO BE LOWER THIS AFTERNOON
WITH THE HREF GUIDANCE SHOWING ONLY A 50-70% CHANCE (COMPARED TO
SUNDAY'S 70-90%) OF WINDS ABOVE 35 MPH FOCUSED ALONG A CORRIDOR FROM
PHOENIX SOUTH/SOUTHEASTWARD, AND NOT NEAR AS WIDESPREAD
COMPARATIVELY. ADDITIONALLY WITH YESTERDAYS RAINFALL DUST MAY NOT BE
AS EASILY LOFTED. ANY ACTIVITY THAT DOES FORM IN OUR REGION TONIGHT
WILL CONTINUE TO BE HIGHLY CONDITIONAL ON UPSTREAM ACTIVITY AND IF
OUTFLOWS FROM CENTRAL AZ HIGH TERRAIN STORMS CAN TRIGGER ADDITIONAL
CELLS. BY TUESDAY, THERMODYNAMICS MAY BE SLIGHTLY MORE FAVORABLE FOR
STRONG STORMS, HOWEVER, FLOW ALOFT WEAKENS FURTHER AND DIRECTIONS
BECOME COMPLEX AS WEAK ANTICYCLONIC AND CYCLONIC CIRCULATIONS BEGIN
TO IMPINGE ON THE REGION, CREATING A DEFORMATION AREA. THE THREAT
FOR LOWER DESERT STORMS WILL BE EVEN MORE CONDITIONAL ON LIFTING
MECHANISMS FROM EARLIER STORMS OR SUBTLE LIFT FROM THE DEFORMATION
ZONES DRAPED ACROSS THE REGION.
OTHERWISE, TEMPERATURES THIS AFTERNOON WILL BE IN THE LOW TO MID
100S ACROSS THE LOWER DESERTS, WITH THE PHOENIX METRO SLIGHT HIGHER
BETWEEN 105F-107F. TUESDAY'S AFTERNOON HIGHS WILL BE SLIGHTLY
WARMER, WITH TEMPERATURES RANGING BETWEEN 105F-111F. DESPITE THE
STORY WEATHER THESE TEMPERATURES ARE STILL A FEW DEGREES ABOVE NORMAL
KEEPING WIDESPREAD MODERATE HEATRISK IN PLACE. WITH THAT SAID BE
SURE TO KEEP HEAT SAFETY IN MIND IF SPENDING TIME OUTDOORS.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
THERE IS STILL EXCELLENT AGREEMENT WITHIN THE EPS AND GEFS
MEMBERS REGARDING THE PLACEMENT OF THE UPPER HIGH OVER THE
NORTHERN PLAINS AND UPPER MIDWEST THROUGH MIDWEEK BEFORE
RETROGRADING OVER THE CENTRAL ROCKIES BY THE LATTER HALF OF THE
WEEK. THE OVERALL POSITION OF THE 500 MB HIGH WILL MAINTAIN DEEP
EASTERLY FLOW ACROSS THE DESERT SOUTHWEST, HELPING ENHANCE
MOISTURE TRANSPORT. LATEST EPS AND GEFS CONTINUE TO SHOW PWATS
HOVERING AROUND 1.5"-1.8" THROUGH THE ENTIRE WEEK WITH LOW-LEVEL
MIXING RATIOS REMAINING BETWEEN 10-12 G/KG. THEREFORE, CONDITIONS
WILL CONTINUE TO REMAIN CONDUCIVE FOR DAILY THUNDERSTORM ACTIVITY
WITH VARIATIONS IN THE OVERALL COVERAGE. BOTH THE MEAN OF THE EPS
AND GEFS SHOW AN UPTICK IN QPF ACROSS THE REGION BY THE END OF
THIS WEEK DUE TO AN EASTERLY WAVE/INVERTED TROUGH APPROACHING THE
AREA BY THURSDAY-FRIDAY. IF THIS OCCURS, THIS TROUGHING FEATURE
WILL LIKELY ENHANCE CONVECTIVE ACTIVITY POTENTIALLY INTRODUCE A
RISK FOR HEAVY RAINFALL ACROSS PORTIONS OF AZ. THIS WILL HAVE TO
BE MONITORED CLOSELY IN THE COMING DAYS.
TEMPERATURES ARE EXPECTED TO PEAK WEDNESDAY MOSTLY BETWEEN
105F-110F ACROSS THE ARIZONA LOWER DESERTS, BUT SOME AREAS OF
MAJOR HEATRISK ENTER THE PICTURE FOR PORTIONS OF SOUTHEAST CA AND
ALONG THE LOWER COLORADO RIVER VALLEY, WHERE LATEST NBM FORECAST
SHOWS HIGHS AS HIGH AS 113F AND LOWS IN THE MIDDLE TO UPPER 80S
THANKS TO THE INEFFICIENT OVERNIGHT RADIATIVE COOLING FROM HIGHER
HUMIDITY AND LIKELY SOME MID-HIGH CLOUD COVER. THE NBM CONTINUES
TO INDICATE TEMPERATURES COOLING TO WELL BELOW NORMAL BY THE END
OF THE WEEK WITH HIGHS FALLING INTO THE 90S TO AROUND 100 DEGREES
ACROSS THE LOWER DESERTS BY FRIDAY. THIS IS LIKELY DUE TO THE
INCREASED SIGNAL FOR THICKER CLOUD COVER AND THE POTENTIAL FOR
MORE WIDESPREAD RAINFALL.
AVIATION
UPDATED AT 1800Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
THE MAIN AVIATION CONCERNS DURING THE PERIOD WILL BE GUSTY OUTFLOW
WINDS AND THUNDERSTORMS IN THE VICINITY OF THE TERMINALS. CURRENT
PROJECTIONS HAVE VCTS SOMEWHERE IN THE WINDOW OF 22-04Z, THOUGH
DIRECT IMPACTS EACH SITE IS UNCERTAIN AT THIS TIME. CONVECTION IN
CLOSER PROXIMITY TO THE AIRPORTS, ALONG WITH MORE DISTANT
ACTIVITY, WILL PUSH OUT MULTIPLE OUTFLOWS, BUT WHEN, HOW STRONG
THEY ARE, AND OUT OF WHAT DIRECTION THEY SWITCH WINDS TO WILL BE
HIGHLY CONDITIONAL ON THE POSITION OF STORMS AND HOW THEY EVOLVE.
ONE THING THAT APPEARS MORE CERTAIN IS THAT POTENTIAL BOUNDARIES
WILL CONTAIN SOME DEGREE OF AN E'RLY COMPONENT. REGARDLESS,
AMENDMENTS ARE LIKELY TO BE NEEDED DURING THE AFTERNOON AND
EVENING. OTHERWISE, WINDS WILL FOLLOW TYPICAL DIRECTIONAL TRENDS,
BUT TIMING OF THE E'RLY SHIFT WILL DEPEND ON THE ABOVE MENTIONED
OUTFLOW(S). SCT-BKN SKIES WILL BE COMMON WITH THE LOWEST BASES
AROUND 8-10 KFT ASSOCIATED WITH AFTERNOON/EVENING CB'S.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR AVIATION CONCERNS ARE EXPECTED OVER THE NEXT 24 HOURS.
WINDS WILL FOLLOW DIURNAL TRENDS AT EACH TERMINAL WITH PERIODS OF
VRB DURING THE OVERNIGHT AND MORNING HOURS TUESDAY. THERE ARE
INDICATIONS OF A WEAK OUTFLOW MOVING THROUGH KIPL THIS AFTERNOON,
BUT CHANCES OF THAT OCCURRING ARE TOO LOW TO INCLUDE IN THE TAF AT
THIS TIME. AT WORST, IT APPEARS IT WOULD INITIATE THE W'RLY SWITCH
AN HOUR OR TWO EARLY AND MAYBE PRODUCE SOME WEAK GUSTS. SCT CLOUDS
WILL BE COMMON DURING THE PERIOD WITH THE LOWEST BASES AROUND
10-12 KFT.
FIRE WEATHER
SEASONABLY HOT TEMPERATURES WILL PREVAIL THROUGH THE NEXT SEVERAL
DAYS AS READINGS WILL BE NEAR TO SLIGHTLY ABOVE NORMAL. DAILY
THUNDERSTORM ACTIVITY WILL BE POSSIBLE THROUGH THIS WEEK WITH THE
POTENTIAL FOR MORE WIDESPREAD WETTING RAINFALL INCREASING ACROSS
THE EASTERN DISTRICTS THROUGHOUT THIS WEEK, WITH HIGHER CHANCES BY
THURSDAY AND FRIDAY. DUE TO INCREASING BOUNDARY LAYER MOISTURE,
AFTERNOON HUMIDITY LEVELS WILL REMAIN IN A 20-30% RANGE WHICH WILL
KEEP ANY FIRE WEATHER CONCERNS AT A MINIMUM. OVERNIGHT RECOVERIES
WILL BE FAIR TO GOOD, OR BETWEEN 40-70%. OUTSIDE OF ANY
THUNDERSTORM DRIVEN OUTFLOW, WINDS SHOULD FAVOR DIURNAL TRENDS
WITH THE TYPICAL AFTERNOON BREEZINESS AROUND 20-25 MPH.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...RYAN/WHITTOCK
LONG TERM...SALERNO/WHITTOCK
AVIATION...RW
FIRE WEATHER...RYAN/WHITTOCK
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