Flooding and Heavy Snow in California, December 28 to 29, 2002

NORTHWEST CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
837 PM PST FRI DEC 27 2002

RECORD SETTING RAINFALL EVENT STILL IN PROGRESS ACROSS THE NORTH
COAST THIS EVENING...WITH HARDEST HIT AREA CONTINUING TO BE HUMBOLDT
COUNTY. THROUGH 4PM...WFO EKA REPORTED 5.61 SINCE MIDNIGHT WITH
UNOFFICIALLY AT LEAST ANOTHER INCH SINCE THEN. THE 5.61 ALREADY
BROKE THE ALL TIME DAILY RECORD RAINFALL RATE FOR THE CITY. HIGHER
PEAKS IN TRINITY COUNTY HAVE ALSO TALLIED UPWARDS OF 8...BUT MOST
VALLEY LOCATIONS THERE REPORTED MORE MODERATE 2-3 VALUES.
TONIGHT...SOME OF THE HEAVIER RAIN HAS BEGUN TO SPREAD INLAND WITH
RAPID INCREASE IN RAINFALL TOTALS NOW BEING EXPERIENCED ACROSS THE
COASTAL RANGE OF THE NORTH COAST INTERIOR ZONE. MOST SMALL STREAMS
AND CREEKS IN HUMBOLDT COUNTY HAVE REACHED BANKFULL AND MANY ROADS
ARE FLOODED.

SATELLITE AND RADAR IMAGERY PAINT THE GRIM PICTURE OF MORE HEAVY
RAIN ON TAP TONIGHT...IN ALMOST THE SAME LOCATIONS THAT HAVE BEEN
HIT THE HARDEST TODAY. WATER VAPOR DOES SHOW A SLIGHT PROMISING
TREND...AS THE AXIS OF HIGHEST PRECIPITABLE WATER PLUME BEGINS TO
GET NUDGED SOUTHWARD. HOWEVER...TOPS CONTINUE TO COOL ALONG THE SLOW
MOVING COLD FRONTAL BOUNDARY AND THE EXIT REGION OF THE UPPER JET IS
BARELY SAGGING SOUTHWARD TONIGHT. 00Z AVN ALSO CONTINUES TREND OF
FURTHER DEVELOPING THE SURFACE LOW NORTH OF 40N...WRAPPING IT UP TO
999MB BY 00Z SUN. THE RECENT COOLING OF THE TOPS NOW APPROACHING NW
CA ARE APPARENTLY IN CONJUNCTION OF THE STRENGTHENING WARM FRONTAL
BAND ASSOCIATED WITH THIS LOW...WHICH SHOULD BE NEAR THE ORCA BORDER
BY AROUND 06Z...WITH THE COLD FRONT (NOW INSIDE 130W) THEN STARTING
TO PULL CLOSER TO SHORE. EXPECT TO SEE SUBTLE CHANGES TOWARD 09Z AS
THE MOST INTENSE WARM ADVECTION SAGS SOUTHWARD TOWARD MENDOCINO
COUNTY AND A LIGHTER 850MB S/SW FLO TAKES OVER ACROSS MUCH OF THE
REDWOOD COAST. WHILE RAIN WILL NOT END...RAIN RATES WILL BEGIN TO
DECREASE TOWARDS 12Z UP NORTH...AND INCREASE IN SOUTHERN CWA WHERE
INTENSE LOW LEVEL CONVERGENCE WILL DEVELOP AS THE FRONT NEARS AND
TAKES ON A MORE NORTH/SOUTH ORIENTATION. UPPER JET DIVERGENCE WILL
ALSO BE MAXIMIZED BETWEEN 12Z-18Z SAT IN SOUTHERN HALF OF
CWA...BEFORE DYNAMICS FINALLY SHIFT EAST WITH THE APPROACH OF THE
UPPER TROF AXIS NEAR 00Z SUN. BEST UVM VALUES WILL ALSO SHIFT
SOUTHEAST VERY LATE TONIGHT...THEN WRAP-AROUND BACK SLIGHTLY TO THE
NORTH AS A POWERFUL VORT MAX HITS THE CENTRAL COAST SAT AFTERNOON.

COLDER AIR WILL FOLLOW THE FRONT AND UPPER TROF...ALTHOUGH MOISTURE
IN THE COLDER AIR WILL BE SOMEWHAT LIMITED. CURRENT WINTER STORM
WATCH HAS MATTERS IN HAND...AND DO NOT HAVE ENOUGH CONFIDENCE AT
THIS TIME TO UPGRADE WITH MODEL RUNS SINCE 00Z YESTERDAY TRENDING
SLOWER WITH LOWERING SNOW LEVELS IN OUR AREA.

ANY UPDATES TO ZONES TONIGHT WILL BE TO TINKER WITH FLOOD WARNINGS
FOR AREA RIVERS...BASED ON RFC GUIDANCE. WILL CONTINUE FLOOD WARNING
FOR HUMBOLDT COUNTY INTO EARLY SATURDAY...WHEN FINALLY THE EASING OF
RAIN RATES SHOULD ALLOW RUNOFF TO BE CONTAINED MORE EFFICIENTLY.

POPS CEC/ACV/EKA +973 UKI ++72

SOROKA

.EKA...SMALL CRAFT ADVISORY PT ST GEORGE TO PT ARENA OUT TO
       60NM.
    ...FLOOD WARNING FOR HUMBOLDT COUNTY THRU EARLY SAT
    ...FLOOD WARNING FOR MAD RIVER
    ...FLOOD WARNING FOR NAVARRO RIVER
    ...FLOOD WARNING EEL RIVER
    ...FLOOD WARNING VAN DUZEN RIVER
    ...FLOOD WARNING FOR RUSSIAN RIVER
    ...WINTER STORM WATCH UPPER TRINITY RIVER AND INTERIO MENDOCINO
       COUNTIES FOR LATE SATURDAY

CAZ001>004-076-281400-
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE EUREKA CA
530 AM PST FRI DEC 27 2002

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHWEST CALIFORNIA

.DAY ONE...TODAY

A STRONG PACIFIC STORM WILL REMAIN NEARLY STATIONARY TODAY PRODUCING
GUSTY WINDS EARLY THIS MORNING AND PERIODS OF HEAVY RAIN. A FLOOD
WARNING IS IN EFFECT FOR THE NAVARRO RIVER AND A FLOOD WATCH IS IN
EFFECT FOR THE EEL RIVER AT FERNBRIDGE. SEE SFOFLSEKA FOR THE LATEST
DETAILS. A WIND ADVISORY IS IN EFFECT FOR GUSTY SOUTHERLY WINDS
ACROSS DEL NORTE AND HUMBOLDT COUNTIES EARLY THIS MORNING. SEE
SFONPWEKA FOR LATEST DETAILS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THE PACIFIC STORM SYSTEM WILL CONTINUE TO IMPACT THE REGION SATURDAY
BEFORE THE FINAL FRONTAL PASSAGE LATE IN THE DAY. PERIODS OF HEAVY
RAIN WILL CONTRIBUTE TO FURTHER RISES ON THE MAINSTEM RIVERS AND
LOCAL FLOODING ON SMALLER CREEKS. THE SNOW LEVEL WILL FALL TO NEAR
2500 FEET SATURDAY NIGHT BEHIND THE FRONT. THERE WILL BE A BRIEF
BREAK IN THE WEATHER SUNDAY BUT ANOTHER SERIES OF FRONTAL PASSAGES
MONDAY AND TUESDAY WILL BRING ADDITIONAL RAIN. A CHANCE OF RAIN WILL
REMAIN THROUGH THURSDAY WITH A MOIST WESTERLY FLOW.

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