Special Weather Statement, NWS Phoenix, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
305 PM MST SAT JUL 26 2014

.SYNOPSIS...
MONSOON MOISTURE WILL REMAIN ACROSS THE REGION THROUGH AT LEAST THE
MIDDLE OF NEXT WEEK...WITH A CHANCE FOR AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS EACH DAY. DAYTIME TEMPERATURES WILL STILL
HOLD ABOVE SEASONAL NORMALS...BUT ARE EXPECTED TO REMAIN BELOW THE
NEAR-RECORD READINGS WE SAW EARLIER THIS WEEK.

&&

.DISCUSSION...
TONIGHT...IR/VIS SATELLITE IMAGERY THIS AFTERNOON REVEALS LITTLE IN
THE WAY OF CUMULUS FORMING ANYWHERE ACROSS OUR CWA. EVEN THOUGH
ATMOSPHERIC MOISTURE IS PLENTIFUL...AND THERE HAS BEEN GOOD
INSOLATION WITH THE LACK OF CLOUD COVER...THE BOUNDARY LAYER REMAINS
COOLER FROM LAST NIGHTS STORMS...THWARTING CONVECTIVE INITIATION.
EVEN WITH THE SOUTH-SOUTHEASTERLY FLOW ALOFT...THE UPPER LEVEL FLOW
IS QUITE CONFLUENT IN THE 500-300MB LAYER AND IS NOT A FAVORABLE
ENVIRONMENT OR SUPPORTIVE OF THUNDERSTORMS. BOTTOM LINE...WAY TOO
MUCH CIN OR INHIBITION TO OVERCOME TO HAVE STORMS FORM OVER THE
LOWER DESERTS THIS AFTERNOON AND EVENING. ITS NOT OUT OF THE
QUESTION TO HAVE AN ISOLATED STORM OR TWO DRIFT OFF THE BAJA
PENINSULAR RANGE/SPINE AND THROW SOME GUSTY WINDS TOWARD EL CENTRO
CALIFORNIA...OR EVEN A FEW STORMS OVER/SOUTH OF SOUTHERN GILA COUNTY
THIS EVENING WITH SOME OUTFLOW APPROACHING THE FAR SOUTHEAST
VALLEY...BUT CHANCES ARE SLIGHT.

SUNDAY...THE FLOW CHANGES LATER THIS EVENING AND OVERNIGHT WITH THE
APPROACH OF A SMALLER DISTURBANCE AHEAD OF A LARGER INVERTED
TROUGH/EASTERLY WAVE PROGGED TO MOVE INTO SOUTHERN ARIZONA SUNDAY
AFTERNOON. THE UPPER LEVEL FLOW DURING THIS PERIOD OF TIME BECOMES
MORE EAST-SOUTHEASTERLY AND 500MB STEERING FLOW MORE PROGRESSIVE
AROUND 15-20KT. ELECTED TO EXPAND SLIGHT CHANCE POPS WESTWARD FOR
EARLY SUNDAY MORNING...SPREADING ACROSS WESTERN MARICOPA YUMA AND LA
PAZ COUNTIES. PER NAM12 AND GFS FORECAST SOUNDINGS...PRECIPITABLE
WATER STEADILY INCREASES TO NEAR 1.75 INCHES BY LATE SUNDAY
AFTERNOON/EVENING OVER THE LOWER DESERTS...AND PRECIPITATION CHANCES
INCREASE AS WELL. STORMS THAT FORM SUNDAY HAVE THE POTENTIAL TO
PRODUCE STRONG GUSTY OUTFLOW WINDS AND GENERATE AREAS OF BLOWING
DUST THAT CAN CREATE DRIVING AND HEALTH HAZARDS. SOME STORMS COULD
PRODUCE HEAVY RAIN AND LOCALIZED FLOODING OF ROADWAYS AND PONDING OF
WATER IN LOW LYING AREAS.

PREVIOUS DISCUSSION...
MONDAY THROUGH FRIDAY...IT APPEARS THAT A LOW-MID GRADE MONSOON WILL
LIKELY PREVAIL THROUGH AT LEAST MONDAY. ALTHOUGH SOUTHERLY FLOW
ALOFT WILL CONTINUE TO PULL MOISTURE INTO THE REGION THROUGH THIS
PERIOD...LIGHT WINDS ALOFT AND THE TENDENCY FOR THE MAIN UPPER HIGH
CENTER TO REMAIN OVER/JUST EAST OF OUR REGION WILL LIKELY HAMPER TS
DEVELOPMENT EACH DAY...WITH INTERSECTING OUTFLOWS BEING THE PRIMARY
SOURCE OF LIFT FOR CONVECTIVE ACTIVITY. TS ACTIVITY COULD BE LESS
FROM TUESDAY ONWARD INTO THE END OF NEXT...SINCE THE GFS HINTS THAT
THE FLOW ALOFT COULD BECOME A MORE WESTERLY...AND DRIER ONE...BUT
CONFIDENCE IN THIS SOLN IS QUITE LOW...AND HAVE KEPT CLIMO-LIKE
VALUES IN THE POP GRIDS FOR NOW...WITH TEMPS IN THE NORMAL TO
SLIGHTLY-ABOVE NORMAL RANGE.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
CONDITIONS UPSTREAM REMAIN QUIET AND THE GENERAL CONSENSUS IS THAT
THUNDERSTORM ACTIVITY THIS AFTERNOON AND EVENING WILL REMAIN OUTSIDE
OF THE PHOENIX AREA. HOWEVER...GIVEN THE MOIST CONDITIONS ISOLATED
THUNDERSTORMS WILL REMAIN A POSSIBILITY...PARTICULARLY ACROSS THE
HIGHER TERRAIN EAST OF GILA COUNTY.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
CONDITIONS CONTINUE TO DESTABILIZE ACROSS SOUTHEASTERN CA AND
ISOLATED THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON.
HOWEVER...PROBABILITIES REMAIN TOO LOW AT THIS TIME TO INCLUDE IN
THE KIPL-KBLH TAFS. ANY STORMS THAT DO FORM HAVE THE POTENTIAL TO
PRODUCE STRONG TO SEVERE WIND GUSTS AND BLOWING DUST.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
NEAR NORMAL TEMPERATURES AND HIGHER RELATIVE HUMIDITY LEVELS ARE
EXPECTED. MINIMUM RELATIVE HUMIDITY LEVELS WILL RANGE FROM 15 TO 25
PERCENT AND RECOVER OVERNIGHT TO 35 TO 45 PERCENT. THERE WILL BE A
DAILY THREAT OF AFTERNOON AND EVENING THUNDERSTORMS...BUT THESE WILL
BE MAINLY CONFINED TO THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA.
WINDS WILL BE GENERALLY LESS THAN 15 MPH...EXCEPT IN THE VICINITY OF
THUNDERSTORMS.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

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

DISCUSSION...MEYERS/PERCHA
AVIATION...HIRSCH
FIRE WEATHER...HIRSCH/MCLANE

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PHOENIX AZ
332 AM MST SAT JUL 26 2014

AZZ020>028-CAZ030>033-271045-
LOWER COLORADO RIVER VALLEY AZ-WEST CENTRAL DESERTS-
NORTHWEST MARICOPA COUNTY-GREATER PHOENIX AREA-
SOUTHERN GILA COUNTY/TONTO NATIONAL FOREST FOOTHILLS-
YUMA/MARTINEZ LAKE AND VICINITY-SOUTHWEST DESERTS-
SOUTHWEST MARICOPA COUNTY-NORTHWEST AND NORTH CENTRAL PINAL COUNTY-
JOSHUA TREE NATIONAL PARK-LOWER COLORADO RIVER VALLEY CA-
RIVERSIDE COUNTY/EASTERN DESERTS-IMPERIAL COUNTY-
332 AM MST SAT JUL 26 2014 /332 AM PDT SAT JUL 26 2014/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST-CENTRAL
ARIZONA...EXTREME SOUTHWEST ARIZONA...EXTREME WEST-CENTRAL
ARIZONA...SOUTH-CENTRAL ARIZONA...SOUTHWEST ARIZONA...WEST-CENTRAL
ARIZONA...EXTREME SOUTHEAST CALIFORNIA AND SOUTHEAST CALIFORNIA.

.DAY ONE...TODAY AND TONIGHT.

ISOLATED TO SCATTERED THUNDERSTORM ARE FORECAST TO DEVELOP AGAIN
TODAY. WHERE THUNDERSTORMS FORM...STRONG GUSTY OUTFLOW WINDS COULD
GENERATE AREAS OF BLOWING DUST CREATING DRIVING AND HEALTH HAZARDS.
SOME STORMS COULD PRODUCE HEAVY RAIN AND LOCALIZED FLOODING OF
ROADWAYS AND PONDING OF WATER IN LOW LYING AREAS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

ISOLATED TO SCATTERED THUNDERSTORM ARE FORECAST TO DEVELOP EACH
DAY. WHERE THUNDERSTORMS FORM...STRONG GUSTY OUTFLOW WINDS COULD
GENERATE AREAS OF BLOWING DUST CREATING DRIVING AND HEALTH HAZARDS.
SOME STORMS COULD PRODUCE HEAVY RAIN AND LOCALIZED FLOODING OF
ROADWAYS AND PONDING OF WATER IN LOW LYING AREAS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED.

NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT

WEATHER.GOV/PHOENIX

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
326 PM MST SAT JUL 26 2014

AZZ024-262300-
GILA AZ-
326 PM MST SAT JUL 26 2014

...SIGNIFICANT WEATHER ADVISORY...

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

SIGNIFICANT WEATHER ADVISORY FOR...
  CENTRAL GILA COUNTY IN EAST CENTRAL ARIZONA

UNTIL 400 PM MST

AT 318 PM MST...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
STRONG THUNDERSTORM 8 MILES NORTHEAST OF SAWMILL...MOVING WEST AT 30
MPH.

WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
  RURAL CENTRAL GILA COUNTY...

LAT...LON 3358 11016 3361 11046 3368 11076 3379 11069
      3385 11057 3383 11051 3383 11033 3367 11013
TIME...MOT...LOC 2226Z 102DEG 28KT 3373 11039

18

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
433 PM MST SAT JUL 26 2014

AZZ024-270000-
GILA AZ-
433 PM MST SAT JUL 26 2014

...SIGNIFICANT WEATHER ADVISORY...

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

SIGNIFICANT WEATHER ADVISORY FOR...
  CENTRAL GILA COUNTY IN EAST CENTRAL ARIZONA

UNTIL 500 PM MST

AT 427 PM MST...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
STRONG THUNDERSTORM 14 MILES NORTHWEST OF HILLTOP...MOVING WEST AT 10
MPH.

WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
  RURAL CENTRAL GILA COUNTY...

LAT...LON 3374 11044 3371 11074 3372 11074 3379 11069
      3381 11066 3385 11057 3385 11056 3383 11051
      3383 11042
TIME...MOT...LOC 2333Z 094DEG 10KT 3380 11055

18

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
821 PM MST SAT JUL 26 2014

AZZ024-270345-
GILA AZ-
821 PM MST SAT JUL 26 2014

...SIGNIFICANT WEATHER ADVISORY...

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

SIGNIFICANT WEATHER ADVISORY FOR...
  SOUTH CENTRAL GILA COUNTY IN EAST CENTRAL ARIZONA

UNTIL 845 PM MST

AT 815 PM MST...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 9 MILES SOUTH OF
HILLTOP TO CUTTER TO 8 MILES NORTHEAST OF CHRISTMAS TO 8 MILES
SOUTHEAST OF WINKELMAN...AND MOVING WEST AT 20 MPH.

WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THESE STORMS.

LOCATIONS IMPACTED INCLUDE...
   CHRISTMAS AND  WINKELMAN...
   HAYDEN...
   GLOBE AND PINAL PEAK...

LAT...LON 3343 11022 3343 11032 3340 11035 3338 11043
      3328 11045 3319 11040 3318 11050 3313 11059
      3314 11062 3311 11068 3307 11069 3307 11072
      3304 11071 3298 11078 3299 11079 3317 11090
      3337 11089 3354 11065 3344 11020
TIME...MOT...LOC 0321Z 092DEG 18KT 3349 11045 3338 11063
          3312 11067 3292 11069

18