Flash Flood Watch 1, NWS Phoenix, AZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PHOENIX AZ
120 PM MST TUE JUL 15 2014

.UPDATE...UPDATED AVIATION DISCUSSION...

&&

.SYNOPSIS...
MONSOON MOISTURE WILL CONTINUE TO INCREASE ACROSS THE REGION
TODAY...WITH A CHANCE OF SHOWERS AND THUNDERSTORMS. COOLER
TEMPERATURES ARE ALSO FORECAST DUE TO CLOUDS...HUMIDITY...AND
RAINFALL. BY WEDNESDAY...A DRYING AND WARMING TREND IS FORECAST TO
LAST INTO FRIDAY. INCREASED HUMIDITY AND A THREAT OF AFTERNOON
THUNDERSTORMS WILL RETURN MAINLY TO PORTIONS OF SOUTHWEST AND SOUTH
CENTRAL ARIZONA THIS WEEKEND.

&&

.DISCUSSION...
EARLY START TO THUNDERSTORM ACTIVITY OVER ARIZONA. AS OF THIS
WRITING...PERSISTENT AREA OVER NORTHERN ARIZONA HAS PROMPTED
FLAGSTAFF AND LAS VEGAS OFFICES TO ISSUE A FLASH FLOOD WATCH FOR
PORTIONS OF THEIR FORECAST AREAS. MEANWHILE...LATER DEVELOPING
STORMS HAVE GOTTEN STARTED OVER SOUTHEAST ARIZONA WHICH APPEARS TO
BE ASSOCIATED WITH SOME SORT OF CYCLONIC FEATURE/INVERTED TROUGH
CENTERED NEAR THE NEW MEXICO BOOTHEEL AND COCHISE COUNTY. EVEN IN
OUR AREA...DESPITE CLOUD COVER...A SMALL BATCH OF STORMS HAS
DEVELOPED NEAR/NORTH OF CAVE CREEK/CAREFREE. EAST OF THE LOWER
COLORADO RIVER VALLEY THE AIRMASS IS VERY MOIST. THUS ANY GIVEN
STORM WILL BE ABLE TO PRODUCE A HEALTHY AMOUNT OF RAINFALL. MORNING
SOUNDINGS INDICATE WEAKER WINDS THROUGH THE COLUMN WHICH WOULD
CONTRIBUTE TO SLOWER STORM MOVEMENT WHICH IN TURN WOULD CONTRIBUTE
TO HEAVIER RAINFALL OVER A LOCALIZED AREA. MULLING OVER THE NEED FOR
A FLASH FLOOD WATCH. QUESTION IS HOW MUCH COVERAGE WILL THERE BE.
LATEST MODELS ARE GENERALLY NOT VERY ENTHUSIASTIC ABOUT PRECIP OVER
OUR FORECAST AREA...ESPECIALLY THE LOWER ELEVATIONS...LIKELY DUE TO
DRY ADVECTION CONTINUING EASTWARD. HOWEVER...THEY HAVE NOT HANDLED
THE EARLY STORM DEVELOPMENT OVER ARIZONA VERY WELL. FOR OUR WESTERN
AREAS...DRY AIR ADVECTION HAS ALREADY BEEN UNDERWAY ON THE BACK SIDE
OF A DEPARTING UPPER LOW CENTERED OFF THE BAJA COAST. ENOUGH LOWER
LEVEL MOISTURE REMAINS THAT A SLIGHT CHANCE REMAINS WARRANTED FOR
TODAY. WILL CONTINUE TO ANALYZE.

&&

PREVIOUS DISCUSSION ISSUED 240 AM...
TODAY AND TONIGHT...
PARTLY CLOUDY SKIES WERE NOTED AT 2 AM AS MONDAY EVENING CONVECTION
DISSIPATED QUICKLY AFTER DARK. LAST EVENINGS WEATHER BALLOON DATA
SHOWED A DRAMATIC INCREASE IN MONSOON MOISTURE ACROSS THE REGION...
ESPECIALLY EXTENDING FROM SAN DIEGO EAST TO PHOENIX AND TUCSON. IN
FACT LOW LEVEL MONSOON MOISTURE VALUES ARE CONSIDERED TO BE
EXCESSIVE AT THIS TIME.

THIS AFTERNOON...MODELS ARE SHOWING WEAK UPPER LEVEL DEFORMATION
ACROSS EASTERN AZ WHICH WILL SUPPORT ANOTHER ROUND OF TALL EASTERN
MOGOLLON RIM AND WHITE MOUNTAIN CONVECTION. WEAK MID LEVEL EASTERLY
STEERING CURRENTS...PLUS MUCH HIGHER THETA-E VALUES ACROSS SOUTH
CENTRAL AZ SHOULD RESULT IN WESTWARD BUILDING CONVECTION OFF THE
HIGHER TERRAIN TOWARD THE LOWER DESERTS BY EVENING. ALSO...WESTWARD
TRENDING CONVECTIVE OUTFLOWS SHOULD BE A FOCUS OF CONVECTION...MUCH
LIKE LAST EVENING VICINITY PHOENIX.

ALTHOUGH UPPER LEVEL SUPPORT IS MISSING IN SOUTHEAST CA AND
SOUTHWEST AZ TODAY...EXCESSIVE MOISTURE IN THIS REGION MAY LEAD TO
ISOLATED HEAT OF THE DAY LOW TOPPED CONVECTIVE STORMS...SOME OF
WHICH COULD STILL PRODUCE HEAVY RAIN.

ALL CONVECTION SHOULD END AFTER DARK DUE TO THE ABSENCE OF ANY
MID/UPPER LEVEL PERTURBATIONS.

WEDNESDAY...
PREVIOUS MODEL RUNS HAD FORECAST A PROFOUND DRYING TREND FROM THE
WEST AND SOUTHWEST WEDNESDAY. RECENT MODEL RUNS HAVE SLOWED THE
DRYING MAGNITUDE...THEREFORE WE HAVE HUNG ON TO A SLIGHT CHANCE OF
AFTERNOON AND EVENING CONVECTIVE POSSIBILITIES OVER THE SOUTH
CENTRAL AZ DESERTS AND MOUNTAINS. SOUTHEAST CA AND SOUTHWEST AZ
SHOULD BE DRIER AND DEVOID OF CONVECTION.

THURSDAY AND FRIDAY...
DRY...WARMER...AND MUCH STABLE ACROSS THE ENTIRE FORECAST AREA...
SOUTHEAST CA TO SOUTH CENTRAL AZ.

SATURDAY AND SUNDAY...
LIKE PREVIOUS MODEL RUNS...WIND FLOW AT ALL LEVELS BACKS FROM THE
SOUTH...OR FROM MEXICO. APPRECIABLE LOW LEVEL MONSOON MOISTURE FIRST
SURGES NORTH INTO THE COLORADO RIVER VALLEY SATURDAY...THEN SPREADS
ACROSS THE ENTIRE FORECAST AREA SUNDAY. A FEW UPPER LEVEL
PERTURBATIONS FROM MEXICO ARE FORECAST TO FLOW NORTH ACROSS THE
COLORADO RIVER VALLEY REGION...RESULTING IN A SLIGHT CHANCE OF
AFTERNOON/EVENING SHWRS/TSTMS EITHER SIDE OF THE COLORADO RIVER
VALLEY ON SATURDAY. CONVECTIVE POSSIBILITIES THEN SPREAD TO
PORTIONS OF SOUTH CENTRAL AZ ON SUNDAY.

MONDAY AND TUESDAY...
A SLIGHT CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS ARE FORECAST
ACROSS THE ENTIRE FORECAST AREA THIS PERIOD...I.E. A TYPICAL MONSOON
FORECAST.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...KSDL...
CONVECTION ALREADY DEVELOPING ACROSS THE DESERTS...GOING TO INCLUDE
AT LEAST A MENTION OF VCTS AT ALL PHOENIX SITES THROUGH EARLY
EVENING. EXACT TIMING AND PLACEMENT WILL BE EXTREMELY TOUGH TO
DETERMINE BUT EXPECT GUSTY NORTHEAST/EAST OUTFLOWS TO MOVE THROUGH
THE TERMINALS LATE THIS AFTERNOON. BKN MID CLOUDS WILL THEN LINGER
THROUGH MOST OF THE NIGHT.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
SOUTH TO SOUTHEASTERLY WINDS AT 12 KTS OR LESS AND SCATTERED MID TO
HIGH CLOUDS EXPECTED THROUGH THE ENTIRE TAF PERIOD. WITH DRIER AIR
BEGINNING TO WORK IN FROM THE WEST...EARLY EVENING WINDS FOR KIPL
MAY VEER TO WESTERLY HEADINGS AND HOLD OVERNIGHT WITH SPEEDS GNLY
10KTS OR LESS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
DRIER AIR WILL CONTINUE TO SPREAD EASTWARD THROUGHOUT MUCH OF CNTRL
ARIZONA THURSDAY/FRIDAY. DAYTIME HUMIDITIES OVER THE LOWER DESERTS
MAY FALL AS LOW AS 10 PERCENT WITH THE INTRODUCTION OF DRIER AIR
INTO THE REGION WITH GOOD RECOVERIES OVERNIGHT. THEREFORE...THE BEST
OPPORTUNITY FOR SHOWERS AND THUNDERSTORMS WILL BE RELEGATED BACK TO
THE HIGHER TERRAIN...INCLUDING GILA COUNTY...WITH LITTLE TO NO
CHANCE OF PRECIPITATION IN SOUTHEAST CALIFORNIA THROUGH THIS PERIOD.
TEMPERATURES WILL GRADUALLY WARM AS THE DRIER AIR WORKS INTO THE
REGION...WITH ABOVE NORMAL TEMPERATURES POSSIBLE INTO THE EARLY
WEEKEND. WINDS WILL REMAIN RATHER LIGHT WITH ONLY OCCASIONAL
AFTERNOON GUSTS...THOUGH SOME STRONGER GUSTS WILL ACCOMPANY ANY
AFTERNOON AND EVENING THUNDERSTORMS IN GILA COUNTY. FORECAST MODELS
INDICATE A RETURN OF MONSOONAL MOISTURE BACK INTO THE REGION
SOMETIME AFTER SUNDAY...WITH SOME MINOR DIFFERENCES WHEN THE DEEPEST
PROFILE WILL BE OVER THE DISTRICTS.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

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

DISCUSSION...AJ
PREVIOUS DISCUSSION...VASQUEZ
AVIATION...LEINS/NOLTE
FIRE WEATHER...NOLTE

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
1215 PM MST TUE JUL 15 2014

AZZ024-028-152000-
GILA AZ-PINAL AZ-MARICOPA AZ-
1215 PM MST TUE JUL 15 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
  EXTREME EAST CENTRAL MARICOPA COUNTY IN SOUTH CENTRAL ARIZONA
  EXTREME NORTH CENTRAL PINAL COUNTY IN SOUTH CENTRAL ARIZONA

UNTIL 100 PM MST

AT 1209 PM MST...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
STRONG THUNDERSTORM 11 MILES SOUTHEAST OF APACHE LAKE.  THIS STORM
WAS NEARLY STATIONARY.

WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH
VERY HEAVY RAIN.

LOCATIONS IMPACTED INCLUDE...
  RURAL FOREST ROADS BETWEEN SUPERIOR AND APACHE LAKE...

SOME UNSECURED OBJECTS WILL BE BLOWN AROUND AND TREE LIMBS COULD BE
SNAPPED OFF. SEEK SHELTER INDOORS UNTIL THE STORM PASSES.

VERY HEAVY RAINFALL MAY CAUSE TEMPORARY PONDING ON SOME ROADS AND
MINOR FLOODING OF POOR DRAINAGE AREAS. IN HEAVY RAINFALL...SLOW DOWN
TO REDUCE THE RISK OF HYDROPLANING...AND LEAVE A SAFE DISTANCE
BETWEEN YOURSELF AND OTHER VEHICLES.

LAT...LON 3338 11096 3327 11132 3354 11126 3356 11101
TIME...MOT...LOC 1912Z 001DEG 2KT 3345 11115

LEINS

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
1222 PM MST TUE JUL 15 2014

AZZ023-028-152000-
PINAL AZ-MARICOPA AZ-
1222 PM MST TUE JUL 15 2014

...SIGNIFICANT WEATHER ADVISORY...

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

SIGNIFICANT WEATHER ADVISORY FOR...
  EAST CENTRAL MARICOPA COUNTY IN SOUTH CENTRAL ARIZONA
  CENTRAL PINAL COUNTY IN SOUTH CENTRAL ARIZONA

UNTIL 100 PM MST

AT 1219 PM MST...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
STRONG THUNDERSTORM NEAR SAN TAN MOUNTAIN PARK...MOVING SOUTH AT 15
MPH.

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

LOCATIONS IMPACTED INCLUDE...
   CENTRAL ARIZONA COLLEGE...
   SAN TAN VALLEY...
   QUEEN CREEK...

SOME UNSECURED OBJECTS WILL BE BLOWN AROUND...TREE LIMBS COULD BE
SNAPPED OFF...AND ISOLATED POWER OUTAGES WILL BE POSSIBLE. SEEK
SHELTER INDOORS UNTIL THE STORM PASSES.

VERY HEAVY RAINFALL MAY CAUSE TEMPORARY PONDING ON SOME ROADS AND
MINOR FLOODING OF POOR DRAINAGE AREAS. IN HEAVY RAINFALL...SLOW DOWN
TO REDUCE THE RISK OF HYDROPLANING...AND LEAVE A SAFE DISTANCE
BETWEEN YOURSELF AND OTHER VEHICLES.

LAT...LON 3289 11158 3301 11184 3329 11166 3323 11146
TIME...MOT...LOC 1922Z 022DEG 13KT 3313 11162

LEINS

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
1259 PM MST TUE JUL 15 2014

AZZ024-028-152100-
GILA AZ-PINAL AZ-
1259 PM MST TUE JUL 15 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
  NORTH CENTRAL PINAL COUNTY IN SOUTH CENTRAL ARIZONA

UNTIL 200 PM MST

AT 1254 PM MST...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
STRONG THUNDERSTORM NEAR TOP OF THE WORLD...MOVING SOUTHWEST AT 5
MPH.

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

LOCATIONS IMPACTED INCLUDE...
   SUPERIOR...
   TOP OF THE WORLD...

SOME UNSECURED OBJECTS WILL BE BLOWN AROUND...TREE LIMBS COULD BE
SNAPPED OFF...AND ISOLATED POWER OUTAGES WILL BE POSSIBLE. SEEK
SHELTER INDOORS UNTIL THE STORM PASSES.

VERY HEAVY RAINFALL MAY CAUSE TEMPORARY PONDING ON SOME ROADS AND
MINOR FLOODING OF POOR DRAINAGE AREAS. IN HEAVY RAINFALL...SLOW DOWN
TO REDUCE THE RISK OF HYDROPLANING...AND LEAVE A SAFE DISTANCE
BETWEEN YOURSELF AND OTHER VEHICLES.

LAT...LON 3330 11084 3320 11092 3324 11095 3314 11110
      3312 11113 3323 11128 3342 11100
TIME...MOT...LOC 1959Z 042DEG 5KT 3329 11099

LEINS