Severe Thunderstorm Warning 9, NWS Phoenix, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
218 PM MST MON JUN 29 2015

.SYNOPSIS...
OCCASIONAL SHOWERS AND THUNDERSTORMS WILL BE COMMON ACROSS THE
MOUNTAINS OF SOUTHERN AND EASTERN ARIZONA THROUGH MUCH OF THE WEEK.
THERE WILL BE SOME OPPORTUNITY FOR SHOWERS TO AFFECT LOWER ELEVATION
DESERT COMMUNITIES DURING THE MIDDLE OF THE WEEK...HOWEVER THE MOST
LIKELY OUTCOME IN THESE AREAS WILL ONLY BE GUSTY WINDS AND SOME
BLOWING DUST. AFTERNOON TEMPERATURES WILL REMAIN SLIGHTLY ABOVE
NORMAL THIS WEEK BEFORE MODERATING BACK DOWN TOWARDS NORMAL BY THE
WEEKEND.

&&

.DISCUSSION...
HIGH-TERRAIN CONVECTION BEGAN FIRING JUST AFTER NOON MST TODAY...AS
WITH THE AFTERNOONS OVER THE WEEKEND. LIGHTNING AND REFLECTIVITY
TRENDS INDICATE THE ACTIVITY OVER THE WHITES AND SOUTHERN RIM NOT
TERRIBLY ORGANIZED OR LONG LASTING AS IT MOVES WESTWARD. DRIER
SURFACE CONDITIONS HAVE WORKED THEIR WAY INTO EASTERN AZ...WITH
DEWPOINTS ACROSS OUR PORTION OF GILA COUNTY LOWERING INTO THE 40S
CURRENTLY. ML THRU UL FLOW RUNNING EASTERLY THROUGH THE
PROFILE...WITH MORE SOUTHEASTERLY HEADINGS AT 700MB. WITH THE SLIGHT
DRY AIR ADVECTION AND LACK OF ORGANIZED FORCING FACTOR...CHANCES
STILL LOOKING SLIM FOR STORMS TO SURVIVE INTO THE LOWER DESERT
ELEVATIONS THIS AFTERNOON AND EVENING. BUFR SOUNDINGS PROG MIXING
RATIOS DROPPING BELOW 10 G/KG AND CAPES STRUGGLING AROUND 500 J/KG
OVER THE PHOENIX AREA DURING THE EVENING. HI-RES FCSTS POINT TO LONG
TRAVELING OUTFLOW PNTL...A MORE LIKELY SCENARIO GIVEN THE DEEP
INVERTED V SOUNDING PROFILE...INITIATING SOMEWHERE ACROSS PIMA
COUNTY AND HEADING NORTHWARD DURING THE EARLY EVENING. PATCHY
BLOWING DUST COVERAGE WAS ALREADY IN THE WEATHER GRIDS ACROSS SW
MARICOPA AND WESTERN PINAL COUNTIES FOR THIS EVENING...FEEL FOR NOW
THAT COVERS THE THREAT UNTIL RADAR TRENDS CAN CONSOLIDATE INTO
SOMETHING MORE SUBSTANTIAL.

UPSTREAM SATELLITE IMAGERY STILL INDICATES SOME BOUNDARY...ALBEIT
SLIGHTLY DIFFUSED OR WEAKER ON THE AFTERNOON WV IMAGERY...AHEAD OF A
N-S ORIENTATED 50KT 300MB JET ON THE EASTERN RIDGE PERIPHERY OVER NE
NM/E CO. THIS FEATURE WILL GRADUALLY WORK THROUGH THE AREA LATER
THIS EVENING...PERSISTING ATLEAST SLIGHT CHANCES OVER THE LOWER
DESERT ELEVATIONS OVERNIGHT. CONCEPTUALLY...THIS WILL BE SIMILAR TO
LAST EVENING...WITH VERY LIMITED CONVECTION SUCH AS A POP-UP
THUNDERSTORM OR TWO MOVING WESTWARD ACROSS THE OPEN DESERTS IN THE
EARLY MORNING HOURS.

THE OPERATIONAL GFS AND ECMWF HINT AT SOME MEASURE OF AN EASTERLY
WAVE ROTATING ABOUT THE SRN PERIPHERY OF THE ANTI-CYCLONE EITHER
TUESDAY OR WEDNESDAY (AS EVIDENCED IN FORECAST Q-VECTOR FIELDS).
CURRENT FORECASTS HAVE POPS GRADUALLY RAMPING UP THROUGH
MIDWEEK...WITH WEDNESDAY THE PEAK CHANCES...30 PERCENT OR LESS...AS
A WEAK SHORTWAVE WORKS INTO THE REGION WHILE THE UPPER RIDGE BEGINS
TO TILT BACK TOWARDS THE PAC NW. MODEL LL/ML CAPES OF 700-1100 J/KG
ARE POSSIBLE ACROSS THE AREA BY THE AFTERNOON AS THE 200/300MB RIDGE
CENTERS BEGIN TO CO-LOCATE OVER THE FOUR CORNERS. DAYTIME
TEMPERATURES THROUGH THE MAJORITY OF THE WORK WEEK WILL REMAIN ON
THE ABOVE-NORMAL SIDE...RANGING 105-110F OR SO WITH FAIRLY MILD
OVERNIGHTS.

THE WRN CONUS PATTERN WILL MODIFY VERY SLIGHTLY DURING THE LATTER
HALF OF THE WEEK...WITH THE HIGH PRESSURE RIDGE CURRENTLY OVER UTAH
BECOME STRETCHED AND ELONGATED IN A NW-SE ORIENTED FASHION. THIS
CONFIGURATION MAY NOT BE AS CONDUCIVE FOR ENHANCED MONSOON
CONVECTION...HOWEVER CERTAINLY WILL NOT PRECLUDE REGIONAL
THUNDERSTORM ACTIVITY. HAVE KEPT POPS ALMOST EXCLUSIVELY LIMITED TO
HIGHER TERRAIN LOCATIONS DURING THIS TIME FRAME AS MOISTURE MAY
BEGIN TO MIX OUT AT LOWER ELEVATIONS. HOWEVER TOWARDS THE END OF
THIS FORECAST PERIOD EARLY NEXT WEEK...THE AFOREMENTIONED
HIGH PRESSURE CORE WILL LIKELY SHIFT WELL BACK TO THE EAST NEAR THE
FOUR CORNERS AND COLORADO...WHICH IS TRADITIONALLY A VERY FAVORABLE
LOCATION WITH ENHANCED DEEP SOUTHEAST FLOW AND GOOD MOISTURE
ADVECTION.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...KSDL...
TYPICAL MONSOONAL PATTERN EXPECTED TONIGHT WITH STORMS FIRING OVER
THE EASTERN MOUNTAINS...AND AN EASTERLY STEERING FLOW WITH THE
POTENTIAL TO BRING THOSE STORMS INTO THE NRN/ERN FRINGES OF THE
GREATER PHOENIX AREA DURING THE EVENING HOURS. A MITIGATING FACTOR
IS SOMEWHAT DRIER AIR LOCATED OVER SERN/ECNTRL AZ WHICH MAY LIMIT
THE COVERAGE OF STORMS TO OUR EAST TONIGHT. AT THIS TIME CONFIDENCE
IS SOMEWHAT LOW THAT THE STORMS WILL SURVIVE INTO THE LOWER DESERTS
AND AS SUCH WE WILL NOT MENTION THUNDER IN THE AREA TAFS. BLOWING
DUST FROM THE SOUTH/SOUTHEAST IS ALSO A THREAT BUT THIS WILL BE
ADDRESSED IN SHORT TERM TAF UPDATES SHOULD THE DUST MATERIALIZE AND
THREATEN TO MOVE INTO THE PHOENIX AREA. FOR THE NEXT 24 HOURS WILL
LIMIT ANY CIGS TO MID LEVEL CLOUD DECKS...120K FEET AND UP.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
EXPECT MOSTLY CLEAR SKIES REST OF THE AFTERNOON AND THROUGH THE
EVENING...WITH THE POTENTIAL FOR MID/HI LEVEL DEBRIS DECKS TO MOVE
INTO THE AREA AFTER 09Z OR SO. OF COURSE THIS DEPENDS ON THE
EXPECTED ROUND OF CONVECTION DEVELOPING OVER THE EASTERN MOUNTAINS
AND THEN MOVING WITH THE ELY STEERING FLOW AND INTO THE WESTERN
DESERTS LATER TONIGHT AND INTO THE MORNING ON TUESDAY. CHANCES FOR
STORMS AFFECTING THE TAF SITES TONIGHT IS NOT ZERO...BUT WAY TOO LOW
TO MAKE ANY MENTION IN THE TAFS AT THIS TIME.

WINDS TO FAVOR THE SOUTH MOST OF THE NEXT 24 HOURS AT KBLH...AND
FAVOR THE SOUTHEAST AT KIPL WITH SPEEDS MOSTLY AOB 12KT.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
A LOW GRADE MONSOON PATTERN WILL BE IN PLACE THROUGH THE WEEK...
CHARACTERIZED BY NEAR OR SLIGHTLY ABOVE NORMAL TEMPERATURES...AND
WIDELY SCATTERED AFTERNOON AND EVENING SHOWERS/THUNDERSTORMS THAT
MOVE FROM EAST TO WEST OFF THE MOUNTAINS AND INTO THE LOWER DESERTS
EACH DAY. FOR THURSDAY INTO SATURDAY THE STORMS WILL PRIMARILY FOCUS
OVER THE HIGHER TERRAIN WITH RATHER LOW CHANCES OF SURVIVING INTO
THE LOWER DESERTS. SUNDAY INTO EARLY NEXT WEEK...AS HUMIDITIES RISE
THERE WILL BE A BETTER CHANCE OF THUNDERSTORMS AND SHOWERS MOVING
INTO THE CENTRAL DESERTS DURING THE OVERNIGHT HOURS. DAYTIME
HUMIDITY VALUES GENERALLY WILL BE IN THE UPPER TEENS TO MID 20
PERCENT RANGE THROUGH SATURDAY WITH HUMIDITIES RISING SEVERAL
PERCENT BY MONDAY. VERY GOOD OVERNIGHT RECOVERY IS EXPECTED EACH
NIGHT. WINDS EACH DAY WILL BE LIGHT AND FAVOR SOUTHWESTERLY
DIRECTIONS THROUGH FRIDAY...BECOMING SOUTHERLY BY THE WEEKEND.

&&

.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT ANY SIGNIFICANT WEATHER 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...NOLTE/MO
AVIATION...CB
FIRE WEATHER...CB

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
410 PM MST MON JUN 29 2015

AZZ027-028-300000-
NORTHWEST AND NORTH CENTRAL PINAL COUNTY AZ-
SOUTHWEST MARICOPA COUNTY AZ-
410 PM MST MON JUN 29 2015

...SIGNIFICANT WEATHER ADVISORY...

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

SIGNIFICANT WEATHER ADVISORY FOR...
  WESTERN PINAL AND SOUTHERN MARICOPA COUNTIES

UNTIL 500 PM MST

AT 408 PM MST...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM OVER
KAKA...OR 35 MILES SOUTHEAST OF GILA BEND. THIS STORM WAS NEARLY
STATIONARY.

WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE... KAKA AND MAINLY RURAL AREAS OF
FAR SOUTHERN MARICOPA COUNTY AND FAR SOUTHEAST PINAL COUNTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

LOCALLY DENSE BLOWING DUST IS POSSIBLE.  IF YOU ENCOUNTER BLOWING
DUST WHILE DRIVING...PULL OVER AS FAR OFF THE ROADWAY AS POSSIBLE AND
PARK. TURN OFF YOUR HEADLIGHTS AND KEEP YOUR FOOT OFF THE BRAKE.

&&

LAT...LON 3280 11266 3280 11203 3272 11207 3272 11214
      3268 11215 3268 11220 3250 11221 3251 11270
TIME...MOT...LOC 2308Z 035DEG 4KT 3254 11231

AJ

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
652 PM MST MON JUN 29 2015

AZZ023-024-027-028-300300-
GREATER PHOENIX AREA AZ-NORTHWEST AND NORTH CENTRAL PINAL COUNTY AZ-
SOUTHERN GILA/TONTO NF FOOTHILLS AZ-SOUTHWEST MARICOPA COUNTY AZ-
652 PM MST MON JUN 29 2015

...SPECIAL WEATHER STATEMENT...

AT 646 PM MST...BLOWING DUST WAS MOVING THROUGH PINAL COUNTY
APPROACHING SOUTHERN PORTIONS OF METRO PHOENIX. REDUCED
VISIBILITIES...RANGING FROM ONE TO THREE MILES...CAN BE EXPECTED
BETWEEN 7 PM AND 8 PM.

LOCATIONS IMPACTED INCLUDE...
AHWATUKEE...CHANDLER...GILBERT...MESA...QUEEN CREEK...
TEMPE...AVONDALE...GOODYEAR...TOLLESON...BUCKEYE...LAVEEN...SUN
LAKES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

LOCALLY DENSE BLOWING DUST IS POSSIBLE.  IF YOU ENCOUNTER BLOWING
DUST WHILE DRIVING...PULL OVER AS FAR OFF THE ROADWAY AS POSSIBLE AND
PARK. TURN OFF YOUR HEADLIGHTS AND KEEP YOUR FOOT OFF THE BRAKE.

&&

LAT...LON 3343 11241 3349 11159 3321 11159 3320 11244
TIME...MOT...LOC 0146Z 035DEG 3KT 3319 11199

AJ