Severe Thunderstorm Warning 60, NWS Phoenix, AZ

AZZ020>028-CAZ030>033-230000-

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1030 AM MST SAT SEP 22 2007

.SYNOPSIS...
A STRONG PACIFIC LOW PRESSURE SYSTEM WILL PUSH THROUGH THE GREAT
BASIN AND THEN INTO THE NORTHERN GREAT PLAINS THE NEXT FEW DAYS. AS
THIS SYSTEM PASSES BY TO OUR NORTH...THERE WILL CONTINUE TO BE
SCATTERED SHOWERS AND THUNDERSTORMS OVER ARIZONA TODAY INTO TONIGHT
...ENDING OVER THE SOUTH-CENTRAL HIGHER TERRAIN ON SUNDAY. COOLER
TEMPERATURES THAT ARE EXPECTED TODAY...WILL BE REPLACED BY WARMER
TEMPERATURES SUNDAY AND MONDAY. HIGHER PRESSURE ALOFT NEXT WEEK WILL
RESULT IN GENERALLY CLEAR SKIES WITH NEAR NORMAL TEMPERATURES.

&&

.SHORT TERM...
TODAY THROUGH MONDAY...
FEED OF LOW AND MID LEVEL MOISTURE CONTINUES ACROSS AZ PORTION OF
THE CWA...BUT RESULTANT CLOUDINESS IS ONLY PRODUCING ISOLD TO SCT
LIGHT SHOWERS PER LOCAL 88D RADARS. MEANWHILE...OFFSHORE LOW IS
STILL SPINNING AROUND ITSELF...BUT THERE ARE SIGNS THAT IT WILL BE
ON THE MOVE SOON. DRY PUNCH IS SEEN ROTATING AROUND THE SYSTEM INTO
OUR SE CA ZONES...AND STABLIZING/DRYING THAT IS SEEN ON FORECAST
SOUNDINGS WOULD INDICATE THE PRECIP THREAT IS JUST ABOUT OVER OUT
THERE. HAVE UPDATED GRIDS/ZONES TO REFLECT THIS THINKING. ELSEWHERE
...FORECAST SOUNDINGS OVER SCNTRL/SW AZ LOCATIONS WOULD ARGUE FOR A
CONTINUED THREAT OF SHOWERS/TSTMS TODAY INTO TONIGHT...THOUGH IT
WOULD APPEAR THAT THE BEST CHANCES AND GREATEST QPFS MAY BE ABOUT TO
SHIFT EWD INTO THE HIGHER TERRAIN AREAS EAST OF PHOENIX. IN ANY
EVENT...LATEST MODEL GUIDANCE STILL ENDS THIS PRECIP EVENT LATE
TONIGHT OVER ALL AREAS BUT ZONE 24...WHERE A CHANCE OF STORMS WILL
CONTINUE INTO THE AFTERNOON HOURS SUNDAY. TEMPS WILL CONTINUE TO BE
TRICKY TODAY...HAVE ALREADY UPDATED A COUPLE OF TIMES TO BUMP THEM
UP FOR THIS AFTERNOON CLOSER TO MOS GUIDANCE. SHOWERS ARE JUST NOT
SUFFLY WIDESPREAD TO KEEP TEMPS DOWN AS LOW AS WE HAD THEM. AS
TROUGH LIFTS OUT TO THE NE SUNDAY INTO MONDAY...EXPECT A RETURN TO
SUNNIER SKIES AND WARMER TEMPS. NO FURTHER UPDATES PLANNED.

&&

.LONG TERM...
MONDAY NIGHT THROUGH FRIDAY...
ECMWF AND GFS REMAIN IN FAIRLY GOOD AGREEMENT WITH THE SHORT TERM
SYSTEM WEAKENING AND MOVING INTO THE CENTRAL PLAINS MONDAY
NIGHT/TUESDAY. THE GREATER SW WILL BE UNDER A DRIER
WEST/SOUTHWESTERLY FLOW TUESDAY THROUGH THURSDAY...ALONG WITH A
WARMING TREND. TEMPS ARE EXPECTED TO REBOUND BACK NEAR 100 ACROSS
THE WARMEST DESERT LOCALES BY THURSDAY. MEANWHILE...MED RANGE MODELS
ARE SUGGESTING ANOTHER...MUCH WEAKER...PAC LOW PRES SYSTEM
DEVELOPING OFF THE CENTRAL CA COAST FRIDAY. WELL WAIT FOR A FEW
MORE RUNS TO SHOW SOME CONSISTENCY IN THE AFOREMENTIONED SYSTEM
MOVING THROUGH BEFORE JUMPING ON A COOLING TREND. OVERALL...FEW
CHANGES WERE MADE TO THE EXTENDED PORTIONS OF THE FORECAST...WITH NO
WEATHER CONCERNS EXPECTED MONDAY NIGHT THROUGH FRIDAY.

&&

.AVIATION...
SEPTEMBER 22 1630 UTC (SEPTEMBER 22 0930 MST)

SHARP MOISTURE BOUNDARY REMAINS OVER THE LOWER DESERTS...WITH
WESTERN TAF SITES RELATIVELY DRY...DEW POINTS DOWN IN THE 50S AT
KIPL. TO THE EAST...CLOUDS...-SHRA AND AN ISOLD -TSRA CONTINUE TO
TRAIN NORTHWARD IN LINES OR CLUSTERS. MOST OF THE ACTIVITY HAS BEEN
NON-CONVECTIVE WITH SOME LOWER SCT-BKN LAYERS. ONE PIREP WEST OF BKX
SHOWED TOPS AT 060 AND SOME LOWER CIGS COULD STILL DEVELOP.
HOWEVER...HAVE AMENDED KPHX FOR BETTER VSBYS...AND LESS IMPACT ON
OPERATIONS. PREVAILING VSBYS NOT EXPECTED TO DROP AS LOW AS 5 MILES.

SEE TAFS PHXTAFPHX...PHXTAFIWA...PHXTAFYUM...LAXTAFBLH AND LAXTAFIPL
FOR MORE DETAILED INFORMATION.

AVIATION DISCUSSION IS NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
SEPTEMBER 22 1115 UTC (SEPTEMBER 22 0415 MST)

MONDAY INTO THE MIDDLE OF NEXT WEEK...LARGE UPPER LEVEL LOW WILL BE
PULLING AWAY FROM THE REGION WITH HIGHER PRESSURE BUILDING ACROSS
THE AREA FROM THE SOUTHWEST. EXPECT AN UPWARD TREND IN TEMPERATURES
AND A DOWNWARD TREND IN RH VALUES THROUGH THE PERIOD...AS A DRIER
GENERALLY WESTERLY FLOW ALOFT SETS UP. NO STRONG WINDS ANTICIPATED
...SO TERRAIN INDUCED DIURNAL PATTERNS EXPECTED TO DOMINATE WIND
FIELDS. ALL ZONES WILL REMAIN DRY WITH NO PRECIPITATION EXPECTED
THROUGH AT LEAST THURSDAY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT

WEATHER.GOV/PHOENIX

SHORT TERM...ESTKE
LONG TERM...WANEK
AVIATION...SIPPLE
FIRE WX...BRECKENRIDGE

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PHOENIX AZ
504 AM MST SAT SEP 22 2007

AZZ021>024-026>028-230700-
WEST CENTRAL DESERTS-NORTHWEST MARICOPA COUNTY-
GREATER PHOENIX AREA-
SOUTHERN GILA COUNTY/TONTO NATIONAL FOREST FOOTHILLS-
SOUTHWEST DESERTS-SOUTHWEST MARICOPA COUNTY-
NORTHWEST AND NORTH CENTRAL PINAL COUNTY-
504 AM MST SAT SEP 22 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST-CENTRAL
ARIZONA...SOUTH-CENTRAL ARIZONA...SOUTHWEST ARIZONA AND WEST-
CENTRAL ARIZONA.

.DAY ONE...TODAY AND TONIGHT

SHOWERS AND THUNDERSTORMS WILL CONTINUE TO SPREAD ACROSS THE AREA
THROUGH THIS EVENING. RAINFALL RATES WILL GENERALLY BE ON THE ORDER
OF ONE TO TWO TENTHS OF AN INCH PER HOUR. TOTAL PRECIPITATION AMOUNTS
THROUGH TONIGHT WILL TYPICALLY RANGE FROM A QUARTER TO A HALF
INCH...THOUGH MAY BE AS HIGH AS TWO INCHES IN SOME AREAS...CAUSING
NORMALLY DRY WASHES TO RUN. IN ADDITION...THERE IS A SLIGHT CHANCE
THAT SOME OF THE THUNDERSTORMS THIS AFTERNOON AND EVENING COULD
BECOME SEVERE...WITH DAMAGING WINDS...HAIL AND FLASH FLOODING THE
PRIMARY THREATS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

SPOTTER ACTIVATION WILL NOT BE NEEDED.

INIGUEZ