319
FXUS65 KPSR 152020
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
120 PM MST SAT AUG 15 2026
KEY MESSAGES.
- DRY CONDITIONS, PARTLY CLOUDY SKIES, AND NEAR NORMAL
TEMPERATURES ARE EXPECTED THIS WEEKEND THROUGH AT LEAST THE
START OF NEXT WEEK.
- EXTREME HEAT WARNING WILL BE IN EFFECT FOR THE LOWER DESERTS OF
SOUTHEAST CALIFORNIA AND SOUTHERN AND CENTRAL ARIZONA FOR MUCH
OF NEXT WEEK.
SHORT TERM /TODAY THROUGH TUESDAY/
SOUTHWEST FLOW DURING THE MONSOON IS NOT IDEAL FOR RAIN CHANCES,
ESPECIALLY ACROSS THE LOWER DESERTS, UNLESS THERE WAS A TROPICAL
SYSTEM, WHICH THERE IS NOT, OR A TROUGH MOVING THROUGH, WHICH THERE
ALSO IS NOT. SO, PRETTY QUIET MONSOON CONDITIONS ARE EXPECTED
THIS WEEKEND THROUGH THE BEGINNING OF NEXT WEEK AS THE SOUTHWEST
FLOW ALOFT PERSISTS, WITH NEAR TO SLIGHTLY BELOW NORMAL MOISTURE
LEVELS. DEW POINT TEMPERATURES WILL ACTUALLY BE ON THE DECLINE
THROUGH MONDAY, WITH GUIDANCE SHOWING MOST LOWER DESERTS FALLING
TO 50-55 DEGREES IN THE AFTERNOONS AND POSSIBLY EVEN DIPPING BELOW
50 DEGREES IN SOME LOCATIONS. A FEW WEAK SHOWERS OR STORMS MAY
STILL DEVELOP OVER TERRAIN FAVORED AREAS TODAY, BUT INSTABILITY IS
VERY LOW (COUPLE HUNDRED J/KG CAPE AT MOST). SO, UPDRAFTS WILL
STRUGGLE AND BE SHORT LIVED. WITH LOWERING DEW POINTS INSTABILITY
WILL BE EVEN LESS THE NEXT FEW DAYS. LATEST HREF NEIGHBORHOOD
PROBABILITY AND PAINTBALLS FOR >40DBZ RADAR ECHOES SHOWS ALMOST NO
COVERAGE FOR SUNDAY AFTERNOON, EXCEPT FOR FAR SOUTHEAST AZ. THERE
WILL BE WEAK TO MODERATE ASCENT FOR SOME LIGHT SHOWERS LATE
TONIGHT THROUGH SUNDAY MORNING ACROSS SOCAL AND WESTERN AZ, FROM
A PASSING SHORTWAVE TROUGH, BUT LIKELY NOT ENOUGH RAIN WILL REACH
THE GROUND TO MEASURE (>0.01").
STRONG HIGH PRESSURE IS STILL SEEN ON SATELLITE DISPLACED WELL TO
THE EAST, OVER THE SOUTHERN MISSISSIPPI RIVER STATES, AND LARGE
SCALE TROFFING IS POSITIONED TO THE WEST. HEIGHT FIELDS OVER THE
LOCAL AREA HAVE STEADILY RISEN OVER THE PAST COUPLE OF DAYS AND
LATEST OBJECTIVE ANALYSIS SHOWS H5 HEIGHTS AROUND 592-594DAM,
WHICH IS CLOSE TO THE 90TH PERCENTILE OF CLIMATOLOGY. TEMPERATURES
AT 850MB HAVE ALSO WARMED A FEW DEGREES. THIS WILL LEAD TO SURFACE
TEMPERATURES THIS AFTERNOON PEAKING NEAR NORMAL, IN THE 102-106
DEGREE RANGE FOR THE LOWER DESERTS. AROUND 2-3 DEGREES OF WARMING
IS EXPECTED INTO SUNDAY AND ANOTHER 2-3 INTO MONDAY, WHICH WILL
BRING A RETURN OF HIGHS REACHING OR EXCEEDING 110 DEGREES IN THE
LOWER DESERTS AND MAJOR HEATRISK BEGINNING MONDAY. THE EXTREME
HEAT WATCH HAS BEEN UPGRADED TO A WARNING STARTING MONDAY FOR ALL
AREAS PREVIOUSLY UNDER THE WATCH. THE COVERAGE OF MAJOR HEATRISK
BECOMES MORE WIDESPREAD BY TUESDAY AS TEMPERATURES CONTINUE TO
WARM, WITH HIGHS FORECAST TO REACH 5-7 DEGREES ABOVE NORMAL AND
LOW TEMPERATURES WARMING BACK INTO THE UPPER 80S TO AROUND 90
DEGREES IN THE LOWER DESERTS.
LONG TERM /WEDNESDAY THROUGH SATURDAY/.
THE WEATHER PATTERN FOR MOST OF NEXT WEEK WILL SEE THE
SUBTROPICAL HIGH BECOMING THE DOMINATE FEATURE ACROSS THE
SOUTHWESTERN U.S. WHILE ITS STRENGTH WILL BARELY CHANGE. GUIDANCE
AGREES THE RIDGE CENTER WILL SHIFT FROM TEXAS ON MONDAY TO
SOMEWHERE OVER ARIZONA BY WEDNESDAY WITH H5 HEIGHTS RISING TO
595-597DM. H5 HEIGHTS OF THIS MAGNITUDE WILL REPRESENT THE 97TH
PERCENTILE OF CLIMATOLOGY FOR THE PERIOD AND TEMPERATURES WILL
FOLLOW WITH FORECAST HIGHS ONLY FALLING SHORT OF DAILY RECORDS BY
A FEW DEGREES EACH DAY. SINCE MOISTURE LEVELS ARE NOW EXPECTED TO
REMAIN FAIRLY LIMITED FOR MUCH OF, IF NOT ALL OF, NEXT WEEK, THE
DAY-TO-DAY CONVECTIVE POTENTIAL SHOULD REMAIN QUITE LOW AND
LIKELY CONFINED TO FAR EASTERN ARIZONA. THE MOST LIKELY SCENARIO
KEEPS THE RIDGE IN FULL CONTROL OVER THE DESERT SOUTHWEST WITH THE
CENTER HOVERING SOMEWHERE OVER ARIZONA AND/OR INTO WESTERN NEW
MEXICO.
THERE IS MODERATE TO HIGH CONFIDENCE FOR A MORE PROLONGED HEAT
EVENT LEADING TO THE NOW EXTREME HEAT WARNING COVERING ALL LOWER
DESERTS AND EXTENDING THROUGH FRIDAY. NBM FORECAST HIGHS SHOW
READINGS ANYWHERE FROM 108-113 DEGREES ACROSS THE LOWER DESERTS
EACH DAY NEXT WEEK WITH OVERNIGHT LOWS NEAR THE 90 DEGREE MARK BY
TUESDAY-WEDNESDAY AS SURFACE DEW POINTS SHIFT A BIT HIGHER.
FORECAST MAJOR HEATRISK HAS ALSO EXPANDED MORE ACROSS THE WESTERN
LOWER DESERTS GOING INTO THE MIDDLE PART OF NEXT WEEK WITH THE
BULK OF THE AREA KEEPING MAJOR HEATRISK LEVELS THROUGH AT LEAST
NEXT FRIDAY. THERE IS UNCERTAINTY IN THE LENGTH OF TIME THIS HEAT
EVENT WILL LAST AS SOME OF THE GUIDANCE SHOWS THE RIDGE CENTER MAY
EVENTUALLY SHIFT MORE TO THE NORTH AND/OR EAST. IF THIS OCCURS,
IT SHOULD HELP TO INCREASE THE AMOUNT OF MONSOON ACTIVITY OVER THE
REGION, EVENTUALLY LEADING TO SOME DEGREE OF COOLING.
AVIATION
UPDATED AT 1730Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO AVIATION WEATHER CONCERNS ARE EXPECTED THROUGHOUT THE FORECAST
PERIOD UNDER INCREASING MID/HIGH CLOUD DECKS. THE OVERALL WIND
PATTERN WILL EXHIBIT TYPICAL DIURNAL TENDENCIES WITH SPEEDS
REMAINING AOB 10 KTS. A LATER THAN USUAL EASTERLY SHIFT IS
ANTICIPATED AT KPHX AND KIWA TONIGHT.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO AVIATION WEATHER CONCERNS ARE ANTICIPATED THROUGHOUT THE TAF
PERIOD UNDER INCREASING MID/HIGH CLOUD DECKS. WINDS WILL FLUCTUATE
BETWEEN SOUTHEAST TO WESTERLY AT KIPL AND SOUTHERLY TO SOUTHWESTERLY
AT KBLH, WITH MODEST AFTERNOON AND EARLY EVENING GUSTS.
FIRE WEATHER
DRY CONDITIONS AND NEAR NORMAL TEMPERATURES WILL PREVAIL THIS
WEEKEND BEFORE TEMPERATURES RISE TO ABOVE NORMAL NEXT WEEK. LITTLE
IF ANY MONSOON STORM ACTIVITY IS EXPECTED OVER THE NEXT SEVERAL
DAYS WITH ONLY ISOLATED AFTERNOON STORMS POSSIBLE OVER THE FAR
EASTERN DISTRICTS. HUMIDITY LEVELS WILL CONTINUE TO DROP THROUGH
MONDAY WITH AFTERNOON MINRHS FALLING INTO THE TEENS ACROSS THE
LOWER DESERTS TO AROUND 25% FOR HIGHER TERRAIN AREAS STARTING
SUNDAY. EXPECT OVERALL LIGHT WINDS GENERALLY FOLLOWING TYPICAL
DIURNAL PATTERNS.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...EXTREME HEAT WARNING FROM 10 AM MONDAY TO 8 PM MST FRIDAY FOR
AZZ530>544-546-548>551-553>555-559.
CA...EXTREME HEAT WARNING FROM 10 AM MONDAY TO 8 PM PDT FRIDAY FOR
CAZ562-565>567-569-570.
SHORT TERM...BENEDICT
LONG TERM...KUHLMAN/BENEDICT
AVIATION...SALERNO
FIRE WEATHER...KUHLMAN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page