Flash Flood Warning 4, NWS Sacramento, CA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
930 AM PST MON JAN 2 2006

.DISCUSSION...
UPPER LOW HAS TAPPED INTO INTO SUB TROPICAL MOISTURE THIS MORNING.
SURFACE LOW SOUTH OF SAN FRANCISCO WITH BOUNDARY EXTENDING EAST
ACROSS CENTRAL CALIFORNIA INTO THE SIERRA FOOTHILLS.  HEAVY RAIN IS
OCCURRING ALONG THIS BOUNDARY.  THE BOUNDARY WILL LIFT SLOWLY NORTH
AND BE ROUGHLY ALONG INTERSTATE 80 THIS AFTERNOON.  URBAN/SMALL
STREAM FLOOD ADVISORY WILL BE CLOSELY MONITORED TO COINCIDE WITH THE
LOCATION OF THE BOUNDARY.  IN THE SIERRA...STRONG OROGRAPHICS WILL
CONTINUE UNTIL AT LEAST 00Z.  SNOW LEVELS APPEAR TO BE AROUND 6500
FEET...THOUGH MUCH LOWER SNOW LEVELS ARE LIKELY IN HEAVIER
SHOWERS.  HEAVY SNOW WARNING SHOULD BE FINE THROUGH THE
AFTERNOON...THOUGH STRONG WINDS ARE ALSO LIKELY.  FARTHER NORTH...H5
COLD POOL -27C MOVES INTO NORCAL BY AFTERNOON.  VERY STRONG UPPER
DIVERGENCE ASSOCIATED WITH 140KT JET CORE ROTATING AROUND BASE OF
THE TROF MAY INDUCE STRONG THUNDERSTORMS LATER THIS MORNING AND THIS
AFTERNOON.  THE BEST LOCATION FOR THESE APPEARS TO BE ALONG THE
I-5 CORRIDOR IN THE NORTHERN SACRAMENTO VALLEY TO THE JUNCTION WITH
I-80 FARTHER SOUTH.  THIS AREA SHIFTS EAST THIS AFTERNOON.  ANY
THUNDERSTORMS MAY CONTAIN HAIL...GUSTY WINDS AND HEAVY RAIN.  ALL
SHOWERS SHOULD END TONIGHT AS WEAK HIGH PRESSURE BUILDS OVER THE
AREA.  AMPLIFICATION SEEN ON THE SATELLITE PICTURE NEAR 145W.
MODELS LIFT THE UPSTREAM SYSTEM CURRENTLY NEAR 40/141 FARTHER
NORTH.  NEXT FRONT SPREADS RAIN ONTO THE COAST TOMORROW AROUND 18Z.
PRECIPITATION SPREADS INLAND DURING THE AFTERNOON.  THIS SYSTEM WILL
LIKELY IMPACT AREAS FROM I-80 NORTH.  SNOW LEVELS WILL BE IN THE
5500 FOOT RANGE IN THE SIERRA TO 4000 FEET IN THE SHASTA/SISKIYOUS.
THIS SYSTEM COULD BRING ANOTHER TWO OR MORE INCHES OF PRECIPITATION
TO SATURATED AREAS IN THE SHASTA-TRINITY MOUNTAINS AND NORTHERN
SACRAMENTO VALLEY...HOWEVER PRECIPITATION WILL BE LESS WIDESPREAD
AND NO TROPICAL MOISTURE TAP IS SHOWN BY THE MODELS.  ALL MEDIUM
RANGE MODELS BRING A RIDGE OVER THE REGION WEDNESDAY AND THURSDAY.  SG

&&

.AVIATION...
AN AREA OF STEADY RAIN IS SPREADING SLOWLY NORTH THROUGH THE AREA.
THE SNOW LEVELS THROUGH THE SIERRA ROUTES ARE RUNNING ROUGHLY FROM
3500 FEET IN THE NORTH NEAR MOUNT LASSEN TO 5500 FEET AROUND TAHOE
AND SOUTH.  THE SOUTHERN ROUTES WILL DECREASE TO NEAR 3500 FEET BY
THIS AFTERNOON. AFTERNOON CLEARING COULD GENERATE THUNDERSTORMS IN
ALL BY THE HIGHEST ELEVATIONS.  THUNDERSTORMS COULD CONTAIN STRONG
AND GUSTY WINDS, HAIL & BRIEF HEAVY SHOWERS.  IMPROVING CONDITIONS
ARE EXPECTED TONIGHT...HOWEVER... IFR VALLEY FOG AND STRATUS COULD
FORM UNDER LIGHT WINDS AND RESIDUAL LOW LEVEL MOISTURE. RC HARTLEY

&&

.STO WATCHES/WARNINGS/ADVISORIES...
SNOW ADVISORY UNTIL 6 PM THIS AFTERNOON FOR WESTERN PLUMAS
COUNTY/LASSEN PARK.

HEAVY SNOW WARNING UNTIL 6 PM THIS AFTERNOON FOR THE WEST SLOPE
NORTHERN SIERRA NEVADA.

URBAN AND SMALL STREAM FLOOD ADVISORY THROUGH NOON MONDAY FOR THE
NORTHERN SAN JOAQUIN VALLEY AND MOTHERLODE.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SACRAMENTO CA
700 AM PST MON JAN 2 2006

CAZ013>019-063-064-066>069-031500-
SHASTA LAKE AREA/NORTHERN SHASTA COUNTY-
BURNEY BASIN/EASTERN SHASTA COUNTY-NORTHERN SACRAMENTO VALLEY-
CENTRAL SACRAMENTO VALLEY-SOUTHERN SACRAMENTO VALLEY-
CARQUINEZ STRAIT AND DELTA-NORTHERN SAN JOAQUIN VALLEY-
MOUNTAINS SOUTHWESTERN SHASTA TO NORTHERN LAKE COUNTIES-
CLEAR LAKE/SOUTHERN LAKE COUNTY-MOTHERLODE-
EAST FOOTHILLS/NORTH SACRAMENTO VALLEY-
WESTERN PLUMAS COUNTY/LASSEN PARK-WEST SLOPE NORTHERN SIERRA NEVADA-
700 AM PST MON JAN 2 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR INTERIOR NORTHERN CALIFORNIA.

.DAY ONE...TODAY

THE CENTER OF A LOW PRESSURE AREA WILL MOVE ONSHORE TODAY AND
BRING INSTABILITY TO INTERIROR CALIFONIA. SHOWERS AND POSSIBLE
STRONG THUNDERSTORMS WILL INCREASE IN AREAIAL COVERAGE AND INTENSITY
FROM LATE THIS MORNING THROUGH THIS AFTERNOON.

* HEAVY SNOW WARNING.........SEE WWUS46 KSTO - WSWSTO FOR DETAILS *

* FLOOD STATEMENT............SEE WGUS86 KSTO - FLSSTO FOR DETAILS *

* SNOW ADVISORY..............SEE WWUS46 KSTO - WSWSTO FOR DETAILS *

.DAYS TWO THROUGH SEVEN... TUESDAY THROUGH SUNDAY

RIVER LEVELS WILL REMAIN HIGH THE NEXT SEVERAL DAYS...OTHERWISE NO
HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.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/STO