Cold in Arizona, April 9 to 10, 2011

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
830 PM MST FRI APR 8 2011

.SYNOPSIS...
LOW PRESSURE...ALONG WITH WIDESPREAD SHOWERS...WILL CONTINUE TO MOVE
THROUGH THE REGION DURING THE OVERNIGHT HOURS. SNOW LEVELS ARE
FORECAST TO FALL TO NEAR 4500 FEET SATURDAY...WITH PERIODS OF HEAVY
SNOW OVER THE MOUNTAINS OF SOUTH CENTRAL ARIZONA ABOVE 5000 FEET.
CLEARING IS EXPECTED SATURDAY NIGHT FOLLOWED BY A WARMING TREND
SUNDAY THROUGH NEXT FRIDAY.

&&

.DISCUSSION...
MID EVENING WATER VAPOR IMAGERY CONTINUES TO CLEARLY SHOW A
DEEPENING AREA OF LOW PRESSURE OVER SOUTHEASTERN CALIFORNIA. IR
IMAGERY SHOWS COOLING CLOUD TOPS ACROSS FAR SOUTHWESTERN
ARIZONA...THIS IS COINCIDENT WITH A LARGE 130+KT JET STREAK ROTATING
AROUND THE BASE OF THE TROUGH AND INTO ARIZONA. REGIONAL RADAR
MOSAIC REVEALS THAT PRECIP HAS BEEN QUICK TO DEVELOP AND EXPAND FROM
YUMA TO QUARTZITE AND TO WICKENBURG SINCE SUNSET. I AM EXPECTING
THIS TREND TO CONTINUE THROUGH THE OVERNIGHT HOURS WITH RAIN SLOWLY
SPREADING INTO THE PHOENIX METRO AROUND MIDNIGHT AND INTO THE
GLOBE/MIAMI AREAS AROUND DAYBREAK. I MADE SOME MINOR ADJUSTMENTS TO
THE POPS FOR THE OVERNIGHT HOURS AND INCREASE POPS WHERE IT IS
ALREADY RAINING...AND STARTED TRIMMING BACK ACROSS PORTIONS OF
SOUTHEAST CALIFORNIA WHERE RAIN HAS ALREADY EXITED THE STATE.

TEMPS HAVE BEEN QUICK TO FALL THIS EVENING AND ARE ALREADY IN THE
UPPER 50S ACROSS THE PHOENIX AREA AS OF 8PM. I BELIEVE TEMPS WILL
CONTINUE TO DROP UNTIL THE RAIN ARRIVES...THEN REMAIN STEADY IN THE
UPPER 40S/LOWER 50S. THIS IS A FEW DEGREES COOLER THAN PREVIOUSLY
FORECAST AND I ADJUSTED THE MIN TEMPS ACCORDINGLY.

NO CHANGES TO THE WINTER WEATHER ADVISORY FOR ELEVATIONS ABOVE 5000
FEET ACROSS SOUTHERN GILA COUNTY/TONTO NATIONAL FOREST. STILL LOOKS
LIKE THE BEST CHANCE OF ACCUMULATING SNOWFALL WILL COME LATE TONIGHT
INTO EARLY SATURDAY MORNING AND NO ADJUSTMENTS WILL BE MADE TO THE
ADVISORY THIS EVENING.

&&

.PREVIOUS DISCUSSION...
SATURDAY THROUGH SATURDAY NIGHT...
SHOWERS WILL CONTINUE ACROSS THE AREA INTO SATURDAY AFTERNOON.
AND...ALTHOUGH THE COLD FRONT WILL HAVE PUSHED INTO WESTERN NEW
MEXICO BY EARLY SATURDAY AFTERNOON... VERY COLD 500 MB
TEMPERATURES...IN THE MINUS 26 TO MINUS 30 DEGREE C RANGE...WILL
PASS THROUGH THE REGION AND REGENERATE AFTERNOON INSTABILITY SHOWERS
JUST ABOUT EVERYWHERE.  THE SNOW LEVEL IN SOUTHERN GILA COUNTY WILL
FALL TO 4500 FEET LATE SATURDAY MORNING...WITH SNOW ACCUMULATIONS OF
2 TO 6 INCHES ABOVE 5000 FEET.  A WINTER WEATHER ADVISORY WILL BE
POSTED FOR SOUTHERN GILA COUNTY ZONE 24 FROM SATURDAY MORNING TO
SATURDAY EVENING.

SHOWERS WILL BEGIN TO TAPPER OFF AREA-WIDE SATURDAY NIGHT...ENDING
BY SUNDAY MORNING.

SUNDAY THROUGH NEXT FRIDAY...
DRY WEATHER WITH A WARMING TREND. AFTERNOON TEMPERATURES BY TUESDAY
WILL WARM TO NEAR SEASONAL NORMALS.

&&

.AVIATION...
PHOENIX AREA...
RAIN HAS BEEN SLOW TO ARRIVE SO FAR...I EXPECT RAIN SHOWERS TO
DEVELOP AROUND KPHX AROUND 06Z AND AT KIWA AROUND 08-09Z. ONCE RAIN
ARRIVES...CIGS SHOULD DROP BELOW 6KFT AND COULD DROP AS LOW AS
2500FT. SREF AVIATION GUIDANCE INDICATES A 70 PERCENT PROBABILITY OF
CIGS BELOW 3KFT BETWEEN 12Z-18Z SATURDAY AND I TRENDED THE FORECAST
IN THAT DIRECTION ACCORDINGLY. VSBYS SHOULD STAY AT 6SM OR GREATER
ALTHOUGH BRIEF REDUCTIONS WITHIN THE STRONGEST SHOWERS ARE POSSIBLE.
WINDS WILL BE BREEZY OUT OF THE WEST...GENERALLY 12G20KTS.
IMPROVEMENTS IN CIGS/VSBYS SHOULD TAKE SHAPE AFTER 00Z.

SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA...
SHOWERS BEGINNING TO TAPER OFF AT THE MOMENT ALTHOUGH CIGS WILL
REMAIN UNTIL AFTER 12Z. LIKEWISE...SOME BREEZINESS IS EXPECTED
THROUGH THE OVERNIGHT HOURS OUT OF THE SOUTHWEST. CONDITIONS SHOULD
CONTINUE TO IMPROVE AT IPL THROUGH THE DAY SATURDAY ALTHOUGH A FEW
STRAY INSTABILITY SHOWERS ARE POSSIBLE AROUND BLH AT ANY TIME
SATURDAY AFTERNOON.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
COOLER TEMPERATURES WILL BEGIN TO WARM UP TO NORMAL STARTING MONDAY
AS A RIDGE BUILDS IN FOLLOWING THE COLD FRONT THAT PASSED THROUGH
FRIDAY/SATURDAY. HUMIDITY LEVELS WILL SEE GOOD OVERNIGHT RECOVERIES
BUT WILL REMAIN LOW AND DRY DURING THE DAY. MOSTLY SUNNY SKIES WITH
SOME HIGH CLOUDS INTERMITTENTLY. WINDS WILL BE MOSTLY CALM AND
DIURNAL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...WINTER WEATHER ADVISORY FROM 6 AM TO 8 PM MST SATURDAY ABOVE
     5000 FEET FOR AZZ024.

CA...NONE.

&&

NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT

WEATHER.GOV/PHOENIX

DISCUSSION...LEINS/VASQUEZ
AVIATION...LEINS
FIRE WEATHER...CDEWEY

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PHOENIX AZ
640 PM MST FRI APR 8 2011

AZZ024-091400-
SOUTHERN GILA COUNTY/TONTO NATIONAL FOREST FOOTHILLS-
640 PM MST FRI APR 8 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST-CENTRAL
ARIZONA.

.DAY ONE...TONIGHT

NO WEATHER HAZARDS ARE EXPECTED.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR AREAS ABOVE 5000 FEET
AND IS IN EFFECT FROM SATURDAY MORNING THROUGH SATURDAY EVENING.
SEVERAL INCHES OF SNOW ARE EXPECTED IN THE HIGHEST ELEVATIONS.

A COLD AND WET PACIFIC LOW PRESSURE SYSTEM WILL BRING WIDESPREAD
SHOWERS OF RAIN AND HIGHER ELEVATION SNOW SATURDAY AFTERNOON AND
EVENING. RAINFALL TOTALS MAY EXCEED ONE INCH IN SOME OF THE FAVORED
UPSLOPE AREAS...AND MAY BE SUFFICIENT TO CAUSE LOCAL FLOODING OF
WASHES...ROADS AND LOW LYING AREAS. THERE WILL BE AT LEAST A SLIGHT
CHANCE FOR THUNDERSTORMS...WHICH COULD ENHANCE RAINFALL TOTALS AS
WELL AS PRODUCE DEADLY CLOUD TO GROUND LIGHTING.

NO HAZARDOUS WEATHER IS EXPECTED SUNDAY THROUGH THE MIDDLE OF NEXT
WEEK AS HIGHER PRESSURE AND WARMER WEATHER RETURNS TO THE AREA.

.SPOTTER INFORMATION STATEMENT...

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

AZZ021>023-026>028-091400-
WEST CENTRAL DESERTS-NORTHWEST MARICOPA COUNTY-GREATER PHOENIX AREA-
SOUTHWEST DESERTS-SOUTHWEST MARICOPA COUNTY-
NORTHWEST AND NORTH CENTRAL PINAL COUNTY-
640 PM MST FRI APR 8 2011

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

.DAY ONE...TONIGHT

A LOW PRESSURE SYSTEM WILL BRING SCATTERED TO NUMEROUS SHOWERS TO THE
AREA TONIGHT...MAINLY AFTER MIDNIGHT. HEAVIER RAINFALL TOTALS MAY
APPROACH ONE HALF INCH AND BE SUFFICIENT TO CAUSE SOME WASHES TO RUN
AS WELL AS MINOR FLOODING OF ROADS AND LOW LYING AREAS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

WIDESPREAD SHOWERS WILL CONTINUE ACROSS THE CENTRAL DESERTS ON
SATURDAY...AND RAINFALL TOTALS MAY APPROACH THREE QUARTERS ON AN INCH
WITH THE HEAVIEST SHOWERS. THERE WILL BE A SLIGHT CHANCE FOR MAINLY
AFTERNOON THUNDERSTORMS...WHICH COULD LOCALLY ENHANCE RAINFALL TOTALS
AS WELL AS PRODUCE DEADLY CLOUD TO GROUND LIGHTING. MODERATE TO HEAVY
RAINFALL MAY CAUSE WASHES TO RUN AS WELL AS LOCAL FLOODING OF ROADS
AND LOW LYING AREAS.

NO HAZARDOUS WEATHER IS EXPECTED SUNDAY THROUGH THE MIDDLE OF NEXT
WEEK AS HIGHER PRESSURE AND WARMER WEATHER RETURNS TO THE AREA.

.SPOTTER INFORMATION STATEMENT...

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

NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT

WEATHER.GOV/PHOENIX