AGUS76 KRSA 091723
 HMDRSA
 
 HYDROMETEOROLOGICAL DISCUSSION
 NATIONAL WEATHER SERVICE / CALIFORNIA NEVADA RFC / SACRAMENTO CA
 930 AM PST TUE FEB 9 2010
 
 ...AN UPPER-LEVEL LOW WILL CONTINUE TO BRING PRECIP TO CENTRAL AND 
 SRN PORTIONS OF THE FORECAST AREA TODAY...
 
 .24 HOUR PRECIPITATION TOTALS (ENDING FEB 9 AT 400 AM PST)...
 
 AN INITIAL LINE OF MOISTURE MOVED ONSHORE ACROSS THE SAN FRANCISCO 
 BAY AREA INLAND OVER THE SACRAMENTO VALLEY AND NORTHERN SIERRA LAST 
 EVENING. OVERNIGHT...AN UPPER LOW DIVING SOUTH-SOUTHEAST ALONG THE 
 NORTHERN CALIFORNIA COAST BROUGHT PRECIP DOWN TO THE CENTRAL COAST 
 AND INLAND OVER THE SHASTA DRAINAGE SOUTH TH THE SOUTHERN SIERRA.
 
 GREATEST TOTALS WERE RECORDED OVER THE NORTHERN SIERRA BETWEEN THE 
 FEATHER RIVER BASIN AND AMERICAN RIVER BASIN WITH 0.25- TO 0.50-INCH 
 (LOCAL 0.75-INCH). 
 
 TOTALS NEAR 0.25-INCH (OR SLIGHTLY HEAVIER) WERE RECORDED OVER THE 
 SHASTA DRAINAGE AND COASTAL MOUNTAINS FROM WESTERN TEHAMA COUNTY 
 SOUTH TO THE BIG SUR COAST.
 
 INLAND OVER THE SACRAMENTO VALLEY AMOUNTS WERE GENERALLY NEAR 
 0.10-INCH...WHILE OVER THE NORTHERN SAN JOAQUIN VALLEY A FEW 
 HUNDREDTHS WERE RECORDED. A COUPLE HUNDREDTHS TO 0.10-INCH WERE ALSO 
 OBSERVED OVER THE SOUTHERN SIERRA.
 
 .METEOROLOGICAL CONDITIONS...
 
 AN UPPER-LEVEL LOW OFF THE CA COAST WILL BRING PERIODS OF RAIN AND 
 SHOWERS TO ALL BUT THE FAR NRN AREAS OF CA TODAY AND CNTRL AND SRN 
 NV AS WELL.  RADAR AND SATELLITE IMAGERY SHOW THE CENTER OF THE 
 UPPER LOW IS JUST OFFSHORE OF SF BAY CURRENTLY...AND MODELS TAKE THE 
 LOW PARALLEL TO THE COAST THROUGH THE DAY...KEEPING IT GENERALLY 
 OFFSHORE AND PLACING IT OFF THE SRN CA COAST BY THIS EVENING.  THUS 
 THE FOCUS OF PRECIP WILL GRADUALLY SHIFT SWD INTO SRN CA THROUGH THE 
 MORNING HOURS.  THE CLOSE PROXIMITY OF THE UPPER LOW COMBINED WITH 
 SWLY WINDS IN THE LOW LEVELS WILL PROVIDE HEAVIER TOTALS ALONG THE 
 TRANSVERSE RANGES LATER THIS MORNING AND THIS AFTERNOON.  PRECIP 
 WILL TAPER OFF ACROSS SRN CA AND SRN NV BY WED MORNING AS THE UPPER 
 LOW MOVES SOUTH AND EAST AWAY FROM THE REGION.
 
 BY WED NIGHT...LIGHT PRECIP WILL SPREAD INTO NW CA ASSOCIATED WITH 
 ISENTROPIC LIFT AND WARM ADVECTION.  MODELS KEEP THE LIGHT PRECIP 
 GOING THROUGH THE DAY THUR BEFORE RAIN RATES BEGIN TO PICK UP THUR  
 AFTERNOON IN ADVANCE OF A COLD FRONT.  ANOTHER FRONT SWINGS THROUGH 
 ON FRI AFTERNOON TO KEEP PRECIP GOING FOR MAINLY THE NRN THIRD OF CA 
 INTO SRN OREGON.  RIDGING BUILDS THIS WEEKEND TO PROVIDE A DRYING 
 TREND FOR THE NORTHERN PORTION OF THE REGION.
 
 
 DAY 1 QPF (TUE 09/12Z TO WED 10/12Z): 0.6-0.8" NEAR THE SRN CA COAST 
 WITH 0.75-1.25" IN THE HIGHER TERRAIN...WITH SLIGHTLY LOWER AMOUNTS 
 ON THE WRN END OF THE TRANSVERSE RANGES. AROUND 0.33-0.6" SANTA 
 LUCIA RANGE AND SANTA CRUZ MTNS. AROUND 0.25" OR LESS FROM THE 
 RUSSIAN/NAPA BASIN TO THE EEL BASIN AND DRY FURTHER NORTH ALONG THE 
 COAST. 0.25-0.4" AMOUNTS THROUGH THE CA CENTRAL VALLEY AND AROUND 
 0.1" OR LESS IN THE LAKE SHASTA REGION. GENERALLY 0.4-0.8" IN THE 
 SRN SIERRAS AND 0.15-0.33" CNTRL AND NRN SIERRAS. GENERALLY LESS 
 THAN 0.1" EAST SLOPES OF THE SIERRAS...NE CA...AND CNTRL NV. 0.25- 
 0.5" ON AVERAGE IN SRN NV AND ADJACENT AREAS OF SERN CA..TRAILING 
 OFF TO LESS THAN 0.1" INTO FAR SE CA.
 
 DAY 2 QPF (WED 10/12Z TO THU 11/12Z): 0.1" OR LESS SRN AND SERN CA 
 AS WELL AS SRN NV. ALSO 0.1" OR LESS NWRN AND FAR NRN CA AND SRN 
 OREGON EXCEPT 0.1-0.25" SMITH BASIN.
 
 DAY 3 QPF (THU 11/12Z TO FRI 12/12Z): GENERAL 0.5-1" AMOUNTS IN THE 
 SMITH AND EEL BASINS AS WELL AS IN THE LAKE SHASTA REGION. 0.25-0.5" 
 AMOUNTS MENDOCINO AND TRINITY COUNTIES TRAILING OFF TO A FEW 
 HUNDREDTHS INTO THE RUSSIAN/NAPA BASINS.  IN THE CENTRAL VALLEY... 
 LESS THAN 0.1" FROM RBL SOUTH TO KMYV AND UP TO AROUND 0.33" FURTHER 
 NORTH. 0.25-0.4" BELOW LAKE SHASTA AND 0.5-0.9" ABOVE THE LAKE.  
 GENERALLY 0.15-0.33" IN FAR NRN CA AND SRN OREGON. LIGHT AMOUNTS 
 0.1" OR LESS FROM I-80 NORTHWARD IN THE SIERRAS AND NE CA EXCEPT UP 
 TO AROUND 0.33" AND LOCALLY HIGHER IN THE FAR NRN SIERRAS.
 
 
 .HYDROLOGICAL CONDITIONS...
 
 PRECIPITATION FORECAST FOR TODAY IS EXPECTED TO PRODUCE ONLY MINOR 
 RISES TO RIVER FORECAST POINTS IN CALIFORNIAS CENTRAL VALLEY 
 REGION... THE RUSSIAN/NAPA... CENTRAL COAST AND SOUTH COASTAL 
 BASINS.  
 
 MINOR RISES TO SOME NORTHERN CALIFORNIA RIVERS AND STREAMS ARE 
 EXPECTED FROM PRECIPITATION FORECAST FOR DAY 3.
 
 OVERFLOW INTO THE SUTTER BYPASS AT TISDALE WEIR IS FORECAST TO END 
 THIS EVENING.
 
 ALL OTHER RIVER FORECAST POINTS ARE EXPECTED TO REMAIN BELOW MONITOR 
 LEVELS DURING THE NEXT SEVERAL DAYS.
 
 
 MORE INFORMATION ON THE CNRFC WEBSITE AT HTTP://WWW.CNRFC.NOAA.GOV
 
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