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CAZ502>506-210000-
HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
853 PM PST THU DEC 19 2024
…AN ACTIVE STORM TRACK ACROSS NORTHERN CALIFORNIA WILL BRING
MODERATE RAINFALL AND AN INCREASED POTENTIAL FOR RAPID RIVER RISES
ON NORTH BAY CREEKS AND STREAMS…
* WHAT…THE STORM DOOR IS WIDE OPEN WITH A VERY ACTIVE STORM TRACK
FORECAST TO IMPACT NORTHERN CALIFORNIA. WET AND UNSETTLED
WEATHER WILL BRING PERIODS OF LIGHT TO MODERATE RAINFALL TO THE
REGION WITH THE BIGGEST IMPACT EXPECTED OVER THE NORTH BAY. THE
FIRST COUPLE OF STORMS THAT ARE FORECAST TO MOVE ACROSS THE
NORTH BAY SATURDAY AND AGAIN ON SUNDAY, WILL LIKELY PRIME THE
SOILS RESULTING IN QUICKER AND MORE NOTEWORTHY RISES OF AREA
STREAMS AND CREEKS BY THE TIME THE THIRD STORM MOVES IN. THIS
THIRD STORM THAT IS EXPECTED TO IMPACT THE NORTH BAY ON MONDAY
AND TUESDAY IS GEARING UP TO BE THE STRONGEST AND WETTEST OF THE
SERIES. THE HIGHER ELEVATIONS OF THE NORTH BAY WILL LIKELY SEE
AROUND 2.0 TO 4.0 INCHES OF PRECIPITATION WHILE NORTH BAY
VALLEYS SEE AROUND 1.30 TO 3.0 INCHES.
MAIN STEM RIVERS ARE FORECAST TO REMAIN BELOW FLOOD STAGE;
HOWEVER, THE EXCEEDANCE PROBABILITIES (OF RISING ABOVE FLOOD
STAGE) ACROSS THE NORTH BAY SHOW A HIGH POTENTIAL FOR EXCEEDING
FLOOD THRESHOLDS EARLY NEXT WEEK. THE RUSSIAN RIVER AT GUERNEVILLE
- GUEC1 HAS A 39% OF EXCEEDING THE ACTION/MONITOR STAGE AND A 34%
OF EXCEEDING THE MINOR FLOOD STAGE . SHEC1- NAPA NEAR SAINT
HELENA HAS A 43% OF EXCEEDING THE ACTION/MONITOR STAGE AND A 20%
OF EXCEEDING THE MINOR FLOOD STAGE. APCC1- NAPA NEAR NAPA HAS A
30% OF EXCEEDING THE ACTION/MONITOR STAGE AND A 11% OF EXCEEDING
THE MINOR FLOOD STAGE . A FEW OTHER RIVERS TO KEEP AN EYE ON THAT
SHOW HIGHER PROBABILITY OF REACHING ACTION/MONITOR OR MINOR FLOOD
STAGE ACCORDING TO THE LATEST CNRFC FORECAST ARE… CTIC1 - LAGUNA
DE SANTA ROSA AT STONY PT RD NEAR COTATI HAS A 80-95% PROBABILITY
OF REACHING ACTION/MONITOR STAGE AND A 40-70% PROBABILITY OF
REACHING MINOR FLOOD STAGE AS EARLY AS SATURDAY WITH CHANCES
INCREASING AS THE WEEKEND PROGRESSES. MWEC1 - MARK WEST CREEK AT
MIRABEL HEIGHTS NOW HAS A 91% PROBABILITY OF REACHING
ACTION/MONITOR STAGE AND A 52% PROBABILITY OF REACHING MINOR FLOOD
STAGE ON TUESDAY. GEYC1 - RUSSIAN RIVER AT GEYSERVILLE HAS A 52%
PROBABILITY OF REACHING ACTION/MONITOR STAGE AND A 41% PROBABILITY
OF REACHING MINOR FLOOD STAGE ON TUESDAY.
* WHERE…SONOMA AND NAPA COUNTIES. LATEST MODEL GUIDANCE SUGGESTS THE
NORTH BAY WILL RECEIVE THE GREATEST ACCUMULATION OF PRECIPITATION
WITH THE HEAVIEST RAINFALL EXPECTED OVER THE NORTH BAY COASTAL
RANGE AND MOUNTAINS.
* WHEN…SATURDAY THROUGH WEDNESDAY. LIGHT TO MODERATE RAINFALL
EXPECTED OVER THE NORTH BAY SATURDAY THROUGH TUESDAY. THE HEAVIEST
RAINFALL ACCUMULATION IS EXPECTED MONDAY INTO TUESDAY.
* ADDITIONAL DETAILS...IN ADDITION TO THE MODERATE RAINFALL AND
LOCALIZED PONDING OF WATER IN LOW-LYING OR POORLY DRAINED AREAS,
SUCH AS FREEWAY OFFRAMPS. LOCALLY STRONG AND GUSTY WINDS MAY
RESULT IN DOWNED TREES, AND POTENTIAL POWER OUTAGES.
CONFIDENCE IS HIGH THAT WE WILL RECEIVE RAINFALL FROM THIS SYSTEM
HOWEVER, CONFIDENCE IS MODERATE WITH RESPECT TO THE EXACT LOCATION
AND TIMING OF THE MOST INTENSE RAINFALL. DETAILS REGARDING THIS
STORM WILL LIKELY CHANGE AS THE SYSTEM NEARS. THEREFORE, STAY TUNED
TO THE LATEST FORECAST FOR THE MOST UP TO DATE WEATHER INFORMATION.
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