876
FXUS65 KPSR 021141 AAA
AFDPSR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PHOENIX AZ
440 AM MST THU JUL 2 2020
UPDATE
UPDATED AVIATION DISCUSSION.
SYNOPSIS
AS HIGH PRESSURE BUILDS INTO THE REGION, TEMPERATURES WILL STEADILY
WARM THROUGH THE WEEK WITH HIGHS CLIMBING BACK ABOVE NORMAL BY THE
WEEKEND. THIS AREA OF HIGH PRESSURE WILL ALSO ALLOW MOISTURE LEVELS
TO RISE RESULTING IN A VERY SLIGHT CHANCE OF THUNDERSTORMS FOR PARTS
OF SOUTH-CENTRAL ARIZONA. MUCH OF THE AREA LIKELY WILL NOT
EXPERIENCE STORMS DIRECTLY, BUT WIND AND DUST MORE COMMON EARLY IN
THIS SEASON, PARTICULARLY THIS AFTERNOON AND EVENING. A GRADUAL
DRYING TREND BEGINNING THIS WEEKEND WILL NOT FAVOR STORM
DEVELOPMENT FOR SOUTH-CENTRAL AZ FOR THE HOLIDAY WEEKEND AND EARLY
NEXT WEEK.
DISCUSSION
CURRENT SATELLITE IMAGERY SHOWS A FEW CLOUDS STRETCHING ACROSS
SOUTHERN MARICOPA AND PINAL COUNTIES AS SOME MIDLEVEL MOISTURE
FROM YESTERDAY'S SOUTHERN ARIZONA CONVECTION ADVANCES NORTHWARD.
MEANWHILE, INCREASING SOUTHERLY FLOW MAY ENHANCE A GULF MOISTURE
SURGE INTO THE FORECAST AREA LATER THIS MORNING. SO FAR, SURFACE
OBSERVATIONS SHOW ONLY A FRAGMENTED SURGE OF 50-55 DEW POINTS
INTO SOUTHWESTERN YUMA COUNTY AND WITHIN A NARROW CORRIDOR FROM
ROCKY POINT NORTHWARD INTO AJO. LATEST TRENDS IN HI-RES GUIDANCE
SHOW THE GULF SURGE FINALLY EXPANDING AND REACHING THE SOUTH-
CENTRAL AND WESTERN ARIZONA DESERTS AROUND SUNRISE.
THE BEST CHANCES FOR PRECIPITATION TODAY ARE CONFINED TO
SOUTHEASTERN ARIZONA AND ALONG THE MOGOLLON RIM. A FEW ELEVATED
SHOWERS AND/OR THUNDERSTORMS ASSOCIATED WITH THE AFOREMENTIONED
MOISTURE SURGE CANNOT BE RULED OUT FOR THIS MORNING. BY THIS
AFTERNOON, THUNDERSTORM CHANCES IMPROVE, ALBEIT VERY SLIGHTLY, AS
DEEPER MOISTURE AND DAYTIME HEATING INCREASE INSTABILITY. STILL,
STRONG CONVECTIVE INHIBITION WILL LIMIT STORM DEVELOPMENT OVER THE
LOWER DESERT RESULTING IN POPS MOSTLY AT OR BELOW 10 PCT. MOST
PLACES WILL NOT SEE ANY STORMS, AND ANY THAT DO, ARE NOT LIKELY TO
SEE MUCH RAINFALL. NONETHELESS, A CLASSIC INVERTED-V ATMOSPHERIC
PROFILE WILL SUPPORT STRONG GUSTY WINDS FROM ANY STORMS THAT DO
DEVELOP. LONG TRAVELING OUTFLOWS ARE ALSO IN THE MIX, AS THE MOST
AGGRESSIVE HI-RES MODELS SUGGEST, WHICH MEANS THAT EVEN IF
CONVECTION IS NEARLY NON-EXISTENT OVER THE FORECAST AREA THIS
AFTERNOON, STORMS THAT DO FORM FARTHER SOUTH IN PIMA COUNTY COULD
POTENTIALLY TRAVEL NORTHWARD INTO SOUTHERN MARICOPA AND PINAL
COUNTIES WHERE BLOWING DUST IS FAVORABLE.
AFTER TOMORROW, ENSEMBLE GUIDANCE SHOWS THE RIDGE REMAINING OVER
THE SOUTHWEST FOR NEXT SEVERAL DAYS WITH MEAN H5 HEIGHTS OF 594DM
SLICING THROUGH ARIZONA. MOISTURE LEVELS, WHICH ARE NOT CURRENTLY
SPECTACULAR, DRY THROUGH THE WEEKEND WHICH WILL KEEP ANY POPS
MINIMAL AND FOCUSED OVER THE HIGHER TERRAIN NORTH AND EAST OF
PHOENIX. MEANWHILE, AFTERNOON TEMPERATURES WILL CONTINUE WARMING
INTO THE 110 DEGREE NEIGHBORHOOD BY SATURDAY AND THEN PERSIST
THROUGH MOST OF NEXT WEEK.
AVIATION
UPDATED AT 1140Z.
SOUTH-CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
A WEAK DISTURBANCE APPROACHING FROM THE SOUTH, AND EMBEDDED IN
SOUTHWEST FLOW ALOFT, WILL SPREAD INCREASING MAINLY MID CLOUD INTO
THE PHOENIX AREA THIS MORNING. EXPECT FEW-SCT DECKS AROUND 10K FEET
BY 14Z, WITH CIGS DEVELOPING DOWN TO AROUND 9K FEET THRU EARLY
AFTERNOON. CLOUDS SHOULD DIMINISH SOMEWHAT DURING THE AFTERNOON, BUT
MORE MID LEVEL DEBRIS CLOUD WILL LIKELY SPREAD INTO THE AREA THIS
EVENING WITH SCT DECKS AROUND 10K AND MID DECKS IN THE 15K BALLPARK.
CANNOT RULE OUT SOME SHOWERS WITHIN THE MID CLOUD STARTING AFTER 15Z
AND PERSISTING PAST NOON, BUT CONFIDENCE TOO LOW AT THIS TIME TO
MENTION THIS IN THE TAFS. ALSO, CANNOT RULE OUT ISOLATED
THUNDERSTORMS DEVELOPING THIS AFTERNOON TO THE SOUTH/SOUTHEAST OF
PHOENIX; MOST LIKELY THEY WOULD NOT DIRECTLY IMPACT THE TERMINALS
BUT COULD SEND SOME SOUTHERLY OUTFLOW INTO THE METRO MOST LIKELY
LATER IN THE AFTERNOON OR EARLY EVENING. AGAIN, THERE IS NO CLEAR
SIGNAL FROM OUR LOCAL/MESOSCALE MODELS ON ANY OUTFLOW WIND SO AT THIS
TIME WILL NOT ALTER THE TYPICAL DIURNAL WIND PATTERNS TO ACCOUNT FOR
THIS. WE WILL CONTINUE TO MONITOR AND ADJUST THE TAFS ACCORDINGLY
WHEN CONFIDENCE IN OUTFLOW WIND INCREASES. FOR NOW WILL CONTINUE TO
GO WITH TYPICAL DIURNAL WIND PATTERNS AT THE TAF SITES OVER THE NEXT
24 HOURS.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
DRY SOUTHWEST WINDS ALOFT WILL CONTINUE OVER THE WESTERN DESERTS
OVER THE NEXT 24 HOURS. SKIES TO BE GENLY CLEAR TODAY WITH MAYBE A
FEW MID OR HIGHER LEVEL DECKS APPROACHING FROM THE WEST DURING THE
EVENING. WINDS WILL FAVOR THE SOUTH NEXT 24 HOURS AT KBLH BECOMING
BREEZY DURING THE AFTERNOON WITH GUSTS OVER 25KT POSSIBLE AT TIMES
AFTER 18Z. WINDS TO TAPER OFF BY 03Z. WINDS WILL FAVOR SOUTHEAST
MUCH OF THE DAY AT KIPL, BECOMING MORE SOUTHWEST AFTER 03Z THIS
EVENING. DO NOT EXPECT AS MUCH WIND AT KIPL AS COMPARED TO KBLH.
FIRE WEATHER
SATURDAY THROUGH WEDNESDAY:
NO CHANGES TO THE FIRE WEATHER OUTLOOK...A WARMING TREND WILL
CONTINUE THROUGH SUNDAY OR MONDAY WITH ABOVE NORMAL HIGHS EXPECTED
THROUGH THE PERIOD. A GRADUAL DRYING TREND IS ALSO UNDERWAY BY
SATURDAY AND CONTINUES THROUGH THE END OF THE PERIOD. HOWEVER,
THERE IS STILL A VERY SLIGHT LINGERING CHANCE OF A FEW ISOLATED
STORMS FOCUSED OVER HIGHER TERRAIN AREAS OF THE EASTERN DISTRICTS
THOUGH RAINFALL MAY NOT BE VERY WIDESPREAD OR HEAVY WITH ANY
ISOLATED STORMS. AFTERNOON MINIMUM HUMIDITY VALUES WILL GENERALLY
FALL BETWEEN THE SINGLE DIGITS IN THE FAR WEST AND THE LOW TO MID
TEENS ELSEWHERE, WHILE OVERNIGHT MAXIMUM RHS LOOK TO VARY BETWEEN
25-40%. TYPICAL AFTERNOON BREEZES WITH GUSTS UP TO 20 MPH WILL BE
LIKELY WITH SOME LOCALIZED STRONGER OUTFLOW WINDS POSSIBLE NEAR
ANY RENEGADE STORMS.
SPOTTER INFORMATION STATEMENT
SPOTTERS SHOULD FOLLOW STANDARD REPORTING PROCEDURES.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
DISCUSSION...AD
AVIATION...CB
FIRE WEATHER...SAWTELLE/SMITH
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