Winter Storm in California, March 27 to 29, 2006

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HANFORD CA
845 PM PST MON MAR 27 2006

.UPDATE...IR SATELLITE DEPICTS EXTENSIVE CLOUD COVER/PRECIP OVER
CENTRAL CA AND A BAROCLINIC BAND EXTENDING SOUTHWEST INTO THE EPAC.
WIDESPREAD LIGHT TO OCCASIONALLY MODERATE RAIN IS AFFECTING MOST OF
THE DISTRICT THIS EVENING. RAINFALL AMOUNTS ACROSS THE VALLEY HAVE
GENERALLY BEEN FROM A FEW HUNDREDTHS TO A TENTH OF AN INCH. THOUGH
ISOLATED 1/4 TO 1/3 INCH AMOUNTS HAVE BEEN RECORDED...MAINLY IN
MERCED COUNTY...AND EVEN 0.48 REPORTED BY A LOS BANOS APRS SITE.
PRECIP IS JUST BEGINNING OVER THE HIGHER ELEVATIONS WHERE SNOW
LEVELS REMAIN HIGH. STILL THINK WE WILL LIKELY SEE A BREAK IN THE
ACTION AFTER THIS INITIAL BAND MOVES THROUGH DURING THE MORNING
HOURS TUESDAY. MEANWHILE...THE MAIN UPPER LOW WILL CONTINUE TO SLIDE
ESE TOWARDS THE NORCAL COAST SPURRING THE DEVELOPMENT OF SHOWERS BY
AFTERNOON. AS THE COLD AIR ALOFT FILTERS IN...SNOW LEVELS WILL DROP
OVER THE SOUTHERN SIERRA AND KERN COUNTY MTNS. CURRENTLY HAVE WINTER
STORM WARNINGS ISSUED FOR ALL MTN ZONES. ADDITIONALLY...INCREASING
INSTABILITY COULD PRODUCE SOME ISOLATED THUNDER TUESDAY. TROUGH AXIS
SHIFTS EAST OF THE CWFA WEDNESDAY MORNING WITH PRECIPITATION THREAT
DIMINISHING THROUGH THE DAY.

.SHORT TERM...FOR THE CENTRAL CALIFORNIA INTERIOR...MONTEREY AND
VANDENBERG RADARS ARE SHOWING THAT THE WARM FRONTAL PRECIPITATION
IS QUICKLY MOVING ONSHORE. SATELLITE IMAGERY SHOWS A NICE BAROCLINIC
LEAF DEVELOPING OFFSHORE AND THIS ENHANCING AREA OF CLOUDS IS
TAKING AIM ON THE CENTRAL COAST. IT APPEARS THAT THE WARM FRONTAL
OVERRUNNING PRECIPITATION COULD BE EXTENSIVE AND FAIRLY HEAVY FOR A
PERIOD OF TIME. WILL LIKELY SEE PRECIPITATION LATE THIS AFTERNOON
OVER THE WEST AND THEN IT WILL SPREAD QUICKLY EAST INTO THE SIERRA.
SNOW LEVELS WILL BE INITIALLY HIGH IN THE SOUTHWEST FLOW ALOFT,
HOWEVER THEY WILL BEGIN TO FALL THIS EVENING AND OVERNIGHT. WITH
THIS TYPE OF SYSTEM WITH TWO DISTINCT PRECIPITATION GENERATORS,
THERE MAY BE AN EXTENDED PERIOD OF LITTLE OR NO RAIN AND SNOW
BETWEEN THE EXIT OF THE WARM FRONT AND THE ARRIVAL OF THE COLDER
AIR, TROUGH AND VORTICITY CENTER. THE LATEST GFS MODEL IS STRONGLY
SUGGESTING THIS WILL BE THE CASE. LATE TONIGHT AND EARLY TUESDAY
MAY END UP BEING MAINLY DRY, HOWEVER WITH THE TROUGH AND COLDER AIR
ARRIVING BY LATE MORNING, PRECIPITATION SHOULD BECOME MORE
WIDESPREAD IN THE AFTERNOON AND TUESDAY NIGHT. THE QPF (QUANTITATIVE
PRECIPITATION FORECAST) FROM THE RIVER FORECAST CENTER IN
SACRAMENTO SUGGESTS THAT UP TO 4 FEET OF SNOW IS POSSIBLE OVER THE
SIERRA BY WEDNESDAY MORNING AND THIS MATCHES UP WITH THE CURRENT
WINTER STORM WARNING QUITE NICELY. THE TRICKY PART OF THE WINTER
STORM SITUATION LIES IN THE KERN COUNTY MOUNTAINS WHERE THE WARM
AIR WILL PERSIST THE LONGEST. THE MORNING VANDENBERG SOUNDING HAD
THE 0 DEGREE CELSIUS LEVEL AT OVER 10000 FEET. THIS WILL OF COURSE
FALL AS THE PRECIPITATION BEGINS HOWEVER AN 8000 + SNOW LEVEL MAY
PERSIST THROUGH THE EVENING HOURS AND THROUGH MUCH OF THE NIGHT.
WILL OPT TO UPGRADE THE WATCH TO A WARNING IN ZONE 95 AND BEGIN IT
AT 400 AM TUESDAY MORNING. AGAIN, THE HIGHER ELEVATIONS WILL
RECEIVE THE MAJORITY OF THE SNOW, HOWEVER ELEVATIONS DOWN TO 4500
FEET WILL RECEIVE SIGNIFICANT SNOW LATER TUESDAY AND TUESDAY NIGHT AS
THE COLD AIR ARRIVES. MODELS ARE STILL IN GOOD AGREEMENT IN PUSHING
THE TROUGH AXIS EAST ACROSS THE FORECAST AREA ON WEDNESDAY MORNING
AND BY THE AFTERNOON THE SYSTEM SHOULD BE MOVING INTO THE GREAT
BASIN. IT LOOKS LIKE BY SUNDOWN ON WEDNESDAY, THE AREA WILL BE DRY
WITH RIDGING BUILDING IN FROM THE WEST. THURSDAY LOOKS DRY AND
WARMER WITH THE RIDGE OVER THE AREA.

.LONG TERM...FOR THURSDAY NIGHT THROUGH MONDAY...LATEST MEDIUM
RANGE MODELS SHOWING FAIRLY GOOD AGREEMENT WITH INTRODUCING ANOTHER
PACIFIC STORM INTO THE DISTRICT FROM THE GULF OF ALASKA ON FRIDAY.
MODEL TIMING FOR THE START OF THIS NEXT STORM IS STILL SET FOR
FRIDAY MORNING...NEAR DAY BREAK...AND OVER-SPREADING THE DISTRICT
DURING THE DAY. MOST MODELS WERE INDICATING THE TROF BECOMING MORE
AMPLIFIED DURING ITS PASSAGE THROUGH CALIFORNIA. THE GFS IS SHOWING
THE LEAST AMOUNT OF AMPLIFICATION...YET STILL ATTEMPTS TO INTRODUCE
PRECIP OVER THE DISTRICT ON FRIDAY. WILL FAVOR THE MORE AMPLIFIED
FLOW WHICH THE ENSEMBLE MEANS WERE ALSO SHOWING. WHILE NCEP ENSEMBLE
MEAN AND SPREAD CHARTS INDICATE SOME UNCERTAINTY WITH THE AMPLITUDE
OF THIS NEXT TROF...THE AMOUNT OF SPREAD REMAINS LOW AND THE MEAN
IS SIMILAR TO THE OTHER MEDIUM RANGE MODELS...WHICH WOULD INDICATE
A HIGHER MEASURE OF RELATIVE PREDICTABILITY FOR THIS SYSTEM.
BY SATURDAY...MODELS LIFT THE TROF OUT OF THE DISTRICT FOR THE START
OF ANOTHER DRY PERIOD. YET...THE FLOW ALOFT BECOMES MORE ZONAL
DURING THIS TIME FRAME. THEREFORE...WILL MAINTAIN CLOUDS OVER THE
DISTRICT WILL ONLY A SLIGHT WARM UP. DURING THIS TIME...MODELS PUSH
ANOTHER TROF THROUGH THE PACIFIC NORTHWEST...NORTH OF THE DISTRICT...
WITH LITTLE INFLUENCE OVER CENTRAL CALIFORNIA. THIS DRY PATTERN
WILL CONTINUE INTO MONDAY AS HEIGHTS RISE UNDER A DEVELOPING RIDGE
FOR EVEN FURTHER WARMING INTO EARLY NEXT WEEK.

&&

.AVIATION...GENERAL VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH
00Z THIS AFTERNOON AHEAD OF A DEVELOPING PACIFIC STORM THAT WILL
RESULT IN DETERIORATING WEATHER CONDITIONS TONIGHT INTO TUESDAY.
AFTER 00Z...WIDESPREAD AREAS OF MVFR CONDITIONS WILL DEVELOP IN
RAIN AND LOWER CEILINGS BEFORE AREAS OF IFR CONDITIONS ARRIVE
OVERNIGHT. MOUNTAIN OBSCURATION WILL BE OBSERVED ACROSS THE SIERRA
NEVADA AND TEHACHAPI MOUNTAINS TONIGHT THROUGH TUESDAY IN MODERATE
SNOW. FOR SPECIFIC DETAILS...PLEASE REFER TO TAFS FOR KMCE...KFAT
AND KBFL.

&&

.HNX WATCHES/WARNINGS/ADVISORIES...WINTER STORM WARNING FOR THE
      SOUTHERN SIERRA NEVADA FROM YOSEMITE PARK TO THE KERN
      COUNTY LINE TONIGHT THROUGH TUESDAY NIGHT.
  ...WINTER STORM WARNING FOR THE KERN COUNTY MOUNTAINS LATE
      TONIGHT THROUGH EARLY WEDNESDAY MORNING.

&&

WWW.WEATHER.GOV/HANFORD

DCH/DUDLEY/MOLINA

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
335 PM PST MON MAR 27 2006

CAZ095>097-281300-
KERN COUNTY MOUNTAINS-SIERRA NEVADA FROM YOSEMITE TO KINGS CANYON-
TULARE COUNTY MOUNTAINS-
335 PM PST MON MAR 27 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE SOUTHERN SIERRA NEVADA
AND THE KERN COUNTY MOUNTAINS.

.DAY ONE...TODAY

SIGNIFICANT SNOWFALL IS EXPECTED TO BEGIN TONIGHT. PLEASE REFER TO
THE LATEST WINTER WEATHER MESSAGE /WWUS46 KHNX/ FOR FURTHER DETAILS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

SIGNIFICANT SNOWFALL IS EXPECTED TO CONTINUE THROUGH EARLY
WEDNESDAY. PLEASE REFER TO THE LATEST WINTER WEATHER MESSAGE /WWUS46
KHNX/ FOR FURTHER DETAILS. OTHERWISE NO HAZARDOUS WEATHER IS
EXPECTED AT THIS TIME.

SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS TO THE SAN JOAQUIN VALLEY NATIONAL WEATHER SERVICE
OFFICE.

CAZ089>094-098-099-281300-
WEST CENTRAL SAN JOAQUIN VALLEY-EAST CENTRAL SAN JOAQUIN VALLEY-
SOUTHWESTERN SAN JOAQUIN VALLEY-SOUTHEASTERN SAN JOAQUIN VALLEY-
MARIPOSA MADERA AND FRESNO COUNTY FOOTHILLS-TULARE COUNTY FOOTHILLS-
INDIAN WELLS VALLEY-SOUTHEASTERN KERN COUNTY DESERT-
335 PM PST MON MAR 27 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE LOWER ELEVATIONS OF
THE CENTRAL CALIFORNIA INTERIOR.

.DAY ONE...TODAY

NO OTHER HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

NO OTHER HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS TO THE SAN JOAQUIN VALLEY NATIONAL WEATHER SERVICE
OFFICE.

MENDENHALL