Severe Thunderstorm Warning 3, NWS Sacramento, CA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
200 AM PST SAT MAR 15 2003

MODERATE TO HEAVY PRECIP ACROSS THE CWA HAS PROMPTED US TO ISSUE AN
URBAN AND SMALL STREAM FLOOD WARNING THRU EARLY THIS MORNING FOR THE
VALLEY AND FOOTHILLS.  RAINFALL RATES HAVE BEEN AVERAGING 0.10-0.20
IN/HR ACROSS MANY LOCATIONS WITH THE CURRENT BAND OF PRECIP.
MEANWHILE LATEST IR IMAGERY SHOWS RAPIDLY COOLING TOPS WITH NEXT
BAND JUST OFFSHORE.

WILL LET WIND ADVISORY FOR ALL AREAS EXPIRE WITH DAYTIME ZONE
ISSUANCE.  MOST WINDS UP TO NOW HAVE BEEN BORDER LINE...AND EXPECT A
GRADUAL DECREASE DURING THE DAY.

FOR WINTER PRODUCTS...WILL LEAVE WINTER STORM WARNINGS IN PLACE FOR
THE SIERRA...WHERE AN ADDITIONAL 1.50-2.50 INCHES OF QPF IS EXPECTED
BETWEEN 12Z-00Z TODAY. LATEST ETA SUGGESTS THAT DECENT PRECIP COULD
EXTEND INTO THE FIRST HALF OF TONIGHT...BUT WILL ALLOW THE DAY SHIFT
THE LUXURY OF EITHER EXTENDING THE WARNING OR PERHAPS DOWNGRADING IT
TO ADVISORY. ONLY CHANGES WILL BE TO CHANGE WARNINGS TO ADVISORIES
ACROSS THE NORTHERN AND COASTAL MOUNTAINS...AS BORDERLINE HIGH SNOW
LEVELS WILL COMBINE WITH BEST DYNAMICS SHIFTING FURTHER SOUTH DURING
THE COURSE OF THE DAY. HOWEVER...COULD SQUEEZE OUT ANOTHER 4-8
INCHES OF SNOW UP THERE ABOVE 5000 FEET.

MAIN EMPHASIS TODAY WILL BE ON SEVERE WEATHER POTENTIAL ACROSS THE
CENTRAL VALLEY AND PERHAPS THE FOOTHILLS.  VERY STEEP LAPSE RATES
EXPECTED THIS AFTERNOON...ESPECIALLY IF WE GET SOME BREAKS IN THE
CLOUDS.  GOOD HELICITY VALUES AND LAPSE RATES SUGGEST SUPERCELL
POTENTIAL AND LOW WET BULBS INDICATE LARGE HAIL THREAT.  GOOD
DISCUSSION FROM STORM PREDICTION CENTER...WHICH PLACES PART OF THE
CENTRAL VALLEY IN THE SLIGHT RISK CATEGORY.

PRECIP SHOULD TAPER TO SHOWERS LATE SATURDAY NIGHT INTO SUNDAY.
ANOTHER SHORTWAVE WILL PIVOT AROUND HUGE GULF OF ALASKA LOW LATER
SUNDAY AFTERNOON INTO EARLY MONDAY WITH ANOTHER ROUND OF MAINLY
LIGHT TO MODERATE PRECIP. SNOW LEVELS SHOULD BE DOWN TO 3500-4500
FEET IN MOST AREAS BY THIS TIME.

EXTENDED...ONLY MAJOR CHANGES WILL BE TO INTRODUCE MORE DRYING ON
TUESDAY AS UPPER LEVEL RIDGE AXIS NOSES INTO NRN CA. MODEL TIMING
DIFFERENCES WITH THE GFS AND THE UKMET/ECMWF/CANADIAN MAKES IT TOUGH
TO PICK OUT THE DRY DAYS FROM WED-FRI...SO WILL PUNT FOR NOW.

.STO...WINTER STORM WARNING TODAY FOR THE SIERRA NEVADA.
    ...SNOW ADVISORY TODAY FOR THE MOUNTAINS OF SHASTA COUNTY
       SOUTHWARD ALONG THE COASTAL RANGE TO NORTHERN LAKE COUNTY.

BASIL

CAZ013>019-063-064-066>069-151500-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SACRAMENTO CA
700 AM PST FRI MAR 14 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR INTERIOR NORTHERN CALIFORNIA.

.DAY ONE...TODAY

AIRMASS WILL REMAIN UNSTABLE TODAY AHEAD OF ANOTHER STORM SYSTEM IN
A SERIES OF STORM SYSTEMS EXPECTED TO MOVE INTO NORTHERN CALIFORNIA
STARTING THIS EVENING.  EACH SYSTEM WILL BRING A THREAT OF MORE RAIN
AND MOUNTAIN SNOW INTO NORTHERN CALIFORNIA THROUGH DAY SEVEN.

A WINTER STORM WARNING REMAINS IN EFFECT TODAY AND TONIGHT FOR THE
WEST SLOPES OF THE NORTHERN SIERRA NEVADA INCLUDING WESTERN PLUMAS
COUNTY.  REFER TO THE WARNING (WWUS46 KSTO WSWSTO) FOR DETAILS.

A WINTER STORM WARNING HAS BEEN ISSUED BEGINNING TONIGHT FOR THE
MOUNTAINS OF SHASTA COUNTY SOUTHWARD TO THE INTERIOR COASTAL RANGE
OF NORTHERN LAKE COUNTY.  REFER TO THE WARNING (WWUS46 KSTO WSWSTO)
FOR DETAILS.

ISOLATED TO SCATTERED THUNDERSTORMS ARE POSSIBLE TODAY AND TONIGHT
FOR THE MOST OF THE INTERIOR NORTHERN CALIFORNIA. REFER TO THE
INTERIOR NORTHERN CALIFORNIA ZONE FORECASTS (FPUS56 KSTO ZFPSTO) FOR
DETAILS).

.DAYS TWO THROUGH SEVEN

A WINTER STORM WARNING CONTINUES THROUGH SATURDAY FOR THE WEST
SLOPES OF THE NORTHERN SIERRA NEVADA INCLUDING WESTERN PLUMAS
COUNTY.  REFER TO THE WARNING (WWUS46 KSTO WSWSTO) FOR DETAILS.

A WINTER STORM WARNING CONTINUES THROUGH SATURDAY FOR PORTIONS OF
THE NORTHERN MOUNTAINS.  REFER TO THE WARNING (WWUS46 KSTO WSWSTO)
FOR DETAILS.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS TO THEIR LOCAL NATIONAL WEATHER SERVICE OFFICE.

THE LATEST WEATHER INFORMATION IS AVAILABLE ON THE INTERNET AT
(LOWER CASE): HTTP://WWW.WRH.NOAA.GOV/SACRAMENTO

LAM