Severe Thunderstorm Warning 31, NWS Phoenix, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1035 AM MST FRI AUG 7 2015

.UPDATE...TO AVIATION DISCUSSION...

&&

.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE EAST OF PHOENIX
TODAY...BUT STORM CHANCES WILL WANE ACROSS THE ENTIRE AREA THIS
WEEKEND AS DRIER AIR MOVES INTO THE AREA. A RETURN TO A MORE TYPICAL
MONSOON FLOW IS EXPECTED BY THE MIDDLE OF NEXT WEEK...ALTHOUGH STORM
CHANCES WILL REMAIN SLIGHTLY BELOW NORMAL FOR MID AUGUST.

&&

.DISCUSSION...
PRE-SUNRISE ISOLATED THUNDERSHOWERS POPPED UP ACROSS THE EAST VALLEY
ALONG A SOUTHWEST TO NORTHEAST BOUNDARY. WHILE MOSTLY LIGHT IN RAIN
ACCUMULATION...A FEW HUNDREDTHS TO A TENTH OF AN INCH HAVE BEEN
RECORDED FROM SUN LAKES THROUGH CHANDLER...MESA AND UP TOWARDS
FOUNTAIN HILLS. SUFFICIENT MOISTURE IS DEFINITELY IN PLACE PER THE
12Z PSR SOUNDING WITH 1.72 IN OF PWAT AND NEARLY IDENTICAL IN THE TWC
SOUNDING. LOOKING AT UPPER LEVEL HIGH DENSITY WINDS /300-500MB/ FAVORABLE
UPSLOPE DIFFLUENCE ACROSS THE EASTERN PORTION OF OUR CWA TODAY WILL
KEEP THE FOCUS OF ACTIVITY TO THESE LOCATIONS. NOT MUCH THINKING HAS
CHANGED FROM THE PREVIOUS DISCUSSION.

&&

.PREVIOUS DISCUSSION.../ISSUED AT 247 AM MST 7 AUG/....
EARLY MORNING WATER VAPOR IMAGERY DEPICTS A RATHER IMPRESSIVE
SYNOPTIC SETUP ACROSS THE REGION...WITH A LARGE UPPER LOW MOVING INTO
CENTRAL CALIFORNIA AND A WEAK ELONGATED SHORTWAVE TROUGH SWEEPING
THROUGH THE LOWER COLORADO RIVER VALLEY. SPC MESOANALYSIS PAGE
SUGGESTS A BROAD AREA OF DEEP /0-6KM/ SHEAR AROUND 40-45KTS
COINCIDENT WITH AN APPROACHING 90KT 300MB JET STREAK. THIS...ALONG
WITH TERRAIN INFLUENCES...CERTAINLY EXPLAINS SHOWERS AND STORMS HAVE
BEEN PERSISTING FOR SUCH A LONG TIME ACROSS SOUTHEAST CALIFORNIA AND
SOUTHWEST ARIZONA. THERE HAS BEEN A BIT OF A NORTHWARD SHIFT IN THE
HEAVIEST PRECIP SINCE 06Z AND STORMS ARE FINALLY BEGINNING TO DETACH
FROM THE MOUNTAINS OF JOSHUA TREE NATIONAL PARK. MEANWHILE SOUTH OF
THE BORDER...A COMPLEX TRIED TO GET GOING AROUND 03Z BUT IS ALREADY
DECAYING. CONVECTION REMAINS ABSENT ACROSS THE PHOENIX METRO WITH
ONLY SOME DEBRIS CLOUDS IN PLACE.

AS THE OFFSHORE UPPER LOW CONTINUES ITS TREK INLAND
TODAY...SOUTHWESTERLY FLOW ALOFT WILL BEGIN TO SCOUR OUT OUR EXISTING
BL MOISTURE. WHILE BL MIXING RATIOS RESIDE AROUND 8-9 G/KG THIS
MORNING...THEY SHOULD BE ABOUT HALF OF THAT BY 00Z WITH THE HIGHEST
AMOUNTS CONFINED TO EASTERN ARIZONA. WHILE SHOWERS AND THUNDERSTORMS
WILL ALMOST CERTAINLY DEVELOP ACROSS THE AREA...SOUTHWESTERLY
STEERING FLOW WILL LIKELY KEEP THE MAJORITY OF THE ACTIVITY FROM
PHOENIX EASTWARD. INHERITED POP FORECAST DEPICTED 10-20 PERCENT
CHANCES ACROSS THE METRO WITH HIGHER VALUES TO THE EAST AND THIS
STILL SEEMS REASONABLE. CONTEMPLATED REDUCING POPS AROUND PHOENIX
HOWEVER THE UPSTREAM MCS AND RESULTING MCV THAT WILL MOVE THROUGH
THE AREA LATER TODAY /ALONG WITH SEVERAL HI-RES MODELS INDICATING
POP-UP STORMS/ LED ME TO LEAVE THE 10-20 POPS IN PLACE. ONLY CHANGE
WAS TO INTRODUCE A MENTION OF PATCHY BLOWING DUST ACROSS NW PINAL
COUNTY GIVEN LOW ANTECEDENT SOIL MOISTURE IN THAT AREA AND NEARBY
PROXIMITY OF STORMS.

NOT SURPRISINGLY...PERSISTENT SOUTHWESTERLY FLOW ACROSS THE AREA
THROUGH THE WEEKEND INTO EARLY NEXT WEEK WILL LEAD TO WELL BELOW
NORMAL PRECIP CHANCES ACROSS THE AREA. HARD TO JUSTIFY POPS ANYWHERE
NEAR CLIMO THIS WEEKEND. A FEW ISOLATED SHOWERS ARE POSSIBLE EAST OF
GLOBE...BUT THAT'D BE ABOUT IT.

DETERMINISTIC AND PROBABILISTIC GUIDANCE SUGGESTS A RETURN TO A MORE
TYPICAL/FAVORABLE MONSOON FLOW /EAST AND SOUTHEAST WINDS IN THE
700-300MB LAYER/ FROM TUESDAY ONWARD. THAT BEING SAID...MOISTURE
APPEARS TO BE LACKING WITH PWATS ONLY RISING TO NORMAL VALUES
/AROUND 1.25 INCHES/. WITHOUT ANY OBVIOUS TRIGGERS IN THE FLOW AND
BL MOISTURE WITHIN A FEW PERCENT OF NORMAL...IT DOESN'T APPEAR
ANYTHING MUCH HIGHER THAN CLIMO POPS ARE WARRANTED AT THIS POINT.
INHERITED FORECAST ALREADY HAD THIS IDEA AND WAS ONLY ADJUSTED
SLIGHTLY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...

LIGHT TO MODERATE RAIN SHOWERS PERSIST IN A ROUGH LINE SLOWLY
LIFTING NORTHWARD ACROSS PORTIONS OF THE EAST AND CENTRAL VALLEY.
LIGHTNING ACTIVITY HAS DIMINISHED WITH THESE IN THE LAST HALF
HOUR...WITH THE FOCUS ON THE STRONGER...MORE ORGANIZED STORMS
FORMING ACROSS FAR EASTERN PINAL AND SOUTHERN GILA COUNTIES. SHOWERS
LIKELY TO CONTINUE TO DRIFT NORTHWARD AND MOSTLY ACROSS THE
CENTRAL/EASTERN PORTIONS OF THE PHX METRO WITH STORMS ACROSS EASTERN
AZ BY MIDDAY. RESULTING SFC WINDS WILL MAINTAIN SOUTH TO
SOUTHEASTERLY HEADINGS...PSBL VRB IF CLOUDS CAN THIN AND GRADUALLY
CLEAR LATER INTO THE AFTN. PLENTY OF MONSOONAL MOISTURE STILL
LINGERS ACROSS THE SOUTH-CENTRAL AZ DESERTS...BUT CONDITIONS ACROSS
WESTERN AZ AND THE WEST VALLEY LOOK FAIRLY STABLE ATTM AND NOT
SUPPORTIVE OF STRONG STORMS EVEN WITH SOME DAYTIME HEATING TO HELP
THINGS ALONG. STORMS LATER TODAY COULD IMPACT THE EASTERN SATELLITE
AIRFIELDS...KSDL...KIWA...KFFZ...WITH VCTS THIS LATE AFTN/EVE AND
POSSIBLE BREEZY OUTFLOW IMPACTS INTO KPHX.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
DRIER AIR MOVING INTO THE REGION TODAY TO CLEAR THE SKIES THIS
MORNING AT BOTH KIPL AND KBLH...WITH THUNDERSTORM ACTIVITY MOVING
WELL OF THE THE EAST. GUSTY S-LY WINDS AT KBLH AND SW-LY WINDS AT
KIPL TO DEVELOP THIS AFTERNOON/EVENING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
LIMITED MOISTURE WILL BE PRESENT ACROSS MOSTLY EASTERN PORTIONS OF
ARIZONA THROUGH THE WEEKEND ALLOWING FOR AFTERNOON/EVENING SLIGHT
CHANCES FOR SHOWERS AND THUNDERSTORMS MAINLY OVER HIGHER TERRAIN
LOCATIONS NORTH AND EAST OF PHOENIX. INCREASING MOISTURE INTO EARLY
NEXT WEEK WILL PUSH CHANCES OF SHOWERS AND THUNDERSTORMS INTO THE
SOUTHERN AND WESTERN ARIZONA DESERTS. MINIMUM RELATIVE HUMIDITIES OF
10 TO 20 PERCENT RANGE WILL BE COMMON ACROSS THE DESERTS THIS
WEEKEND WITH SOME IMPROVEMENT GOING INTO EARLY NEXT WEEK. DRIEST
LOCATION WILL BE SOUTHEAST CALIFORNIA THIS WEEKEND WITH MINIMUM RH
VALUES INTO THE SINGLE DIGITS. HIGH TEMPERATURES WILL BE AROUND OR
SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD. WINDS WILL BE LIGHT
THROUGH MUCH OF THE PERIOD FOLLOWING TYPICAL DIURNAL DIRECTIONS
EXCEPT FOR AFTERNOON UPSLOPE BREEZES GUSTING AT TIMES UP TO 20 MPH.

&&

.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT CONDITIONS ACCORDING TO STANDARD
OPERATING PROCEDURES.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&

VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX

DISCUSSION...DEWEY
PREVIOUS DISCUSSION...LEINS
AVIATION...NOLTE/PERCHA
FIRE WEATHER...KUHLMAN/CB

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SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
729 AM MST FRI AUG 7 2015

AZZ023-024-028-071515-
GREATER PHOENIX AREA AZ-NORTHWEST AND NORTH CENTRAL PINAL COUNTY AZ-
SOUTHERN GILA/TONTO NF FOOTHILLS AZ-
729 AM MST FRI AUG 7 2015

...SIGNIFICANT WEATHER ADVISORY...

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

SIGNIFICANT WEATHER ADVISORY FOR...
  NORTH CENTRAL PINAL AND NORTHEASTERN MARICOPA COUNTIES

UNTIL 815 AM MST

AT 727 AM MST...DOPPLER RADAR WAS TRACKING AN LINE OF SCATTERED
SHOWERS AND EMBEDDED STRONG THUNDERSTORM OVER THE SOUTHEAST
VALLEY MOVING NORTH NORTHEAST AT 25 MPH.

WINDS IN EXCESS OF 40 MPH AND PERIODS OF BRIEF BUT HEAVY
RAINFALL WILL BE POSSIBLE WITH THESE STORMS.

LOCATIONS IMPACTED INCLUDE...
MESA...CHANDLER...SCOTTSDALE...GILBERT...TEMPE...APACHE JUNCTION...
FOUNTAIN HILLS...SUN LAKES...EAST MESA...QUEEN CREEK...GOLDFIELD
RANCH...SEVILLE...SAGUARO LAKE...MESA RIVERVIEW MALL...GILBERT CITY
HALL...SALT RIVER TUBING RECREATION AREA...FREESTONE PARK...USERY
MOUNTAIN PARK...SUPERSTITION SPRINGS MALL AND SAN TAN VILLAGE MALL.

LAT...LON 3316 11168 3324 11195 3370 11183 3359 11144
TIME...MOT...LOC 1427Z 190DEG 23KT 3330 11179

NOLTE

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
1141 AM MST FRI AUG 7 2015

AZZ024-071930-
SOUTHERN GILA/TONTO NF FOOTHILLS AZ-
1141 AM MST FRI AUG 7 2015

...SIGNIFICANT WEATHER ADVISORY...

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

SIGNIFICANT WEATHER ADVISORY FOR...
  EASTERN MARICOPA AND NORTH CENTRAL GILA COUNTIES

UNTIL 1230 PM MST

AT 1140 AM MST...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM
NEAR TONTO NATIONAL MONUMENT...OR NEAR ROOSEVELT...MOVING NORTH
NORTHEAST AT 10 MPH.

WIND GUSTS UP TO 50 MPH...MODERATE TO HEAVY RAINFALL AND
DANGEROUS LIGHTNING WILL BE POSSIBLE WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
TONTO NATIONAL MONUMENT.
SOUTH END OF ROOSEVELT LAKE.

LAT...LON 3376 11099 3374 11096 3365 11092 3356 11100
      3358 11112 3379 11113
TIME...MOT...LOC 1840Z 190DEG 7KT 3363 11106

NOLTE

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
1144 AM MST FRI AUG 7 2015

AZZ024-071930-
SOUTHERN GILA/TONTO NF FOOTHILLS AZ-
1144 AM MST FRI AUG 7 2015

...SIGNIFICANT WEATHER ADVISORY...

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

SIGNIFICANT WEATHER ADVISORY FOR...
  CENTRAL GILA COUNTY

UNTIL 1230 PM MST

AT 1143 AM MST...DOPPLER RADAR WAS TRACKING A SLOW MOVING STRONG
THUNDERSTORM NEAR GLOBE AND ALONG HIGHWAY 70.

WIND GUSTS UP TO 50 MPH...HEAVY RAINFALL AND DANGEROUS LIGHTNING
WILL BE POSSIBLE WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
GLOBE AND CUTTER.

LAT...LON 3333 11066 3334 11079 3358 11084 3355 11052
TIME...MOT...LOC 1843Z 180DEG 4KT 3339 11073

NOLTE

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
1151 AM MST FRI AUG 7 2015

AZZ024-071945-
SOUTHERN GILA/TONTO NF FOOTHILLS AZ-
1151 AM MST FRI AUG 7 2015

...SIGNIFICANT WEATHER ADVISORY...

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

SIGNIFICANT WEATHER ADVISORY FOR...
  CENTRAL GILA COUNTY

UNTIL 1245 PM MST

AT 1151 AM MST...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM
OVER SAN CARLOS...OR 17 MILES EAST OF GLOBE. THIS STORM WAS NEARLY
STATIONARY.

HALF INCH HAIL AND WIND GUSTS OF 50 TO 55 MPH WILL BE POSSIBLE WITH
THIS STORM.

LOCATIONS IMPACTED INCLUDE...
SAN CARLOS.

LAT...LON 3340 11040 3339 11042 3338 11045 3329 11046
      3330 11053 3349 11056 3350 11037
TIME...MOT...LOC 1851Z 179DEG 4KT 3334 11049

NOLTE