Hydrometeorological Discussion
Issued by NWS California-Nevada RFC

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AGUS76 KRSA 221720
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HYDROMETEOROLOGICAL DISCUSSION
NATIONAL WEATHER SERVICE / CALIFORNIA NEVADA RFC / SACRAMENTO CA
920 AM PST SAT NOV 22 2014

...PRECIP CONTINUES MAINLY NORTH TODAY...
...STRONG HIGH PRESSURE WILL DOMINATE SUNDAY THRU THANKSGIVING...

.24 HOUR PRECIPITATION TOTALS (ENDING NOV 22 AT 400 AM PST)...

AN EXITING SYSTEM ACROSS SOUTHERN CA BROUGHT LIGHT PRECIP TO AREAS
BETWEEN SW SAN BERNARDINO COUNTY TO THE US/MEXICO BORDER. TOTALS AT
LOWER ELEVATIONS WERE GENERALLY NEAR OR LESS THAN 0.10-INCH.
HOWEVER...ACROSS THE HIGHER TERRAIN FROM SW SAN BERNARDINO COUNTY
SOUTH OVER RIVERSIDE AND SAN DIEGO COUNTIES TOTALS WERE IN THE 0.25-
TO 0.50-INCH RANGE. A FEW LOCATIONS UNDER HEAVIER CELLS IN CENTRAL
SAN DIEGO COUNTY APPROACHED 1.00-INCH.

THE NEXT SYSTEM MOVED ACROSS THE UPPER KLAMATH RIVER BASIN SOUTH TO
THE I-80 CORRIDOR OF CA FROM THE AFTERNOON TO OVERNIGHT HOURS. LIGHT
PRECIP ALSO REACHED OVER NW NEV.

HEAVIEST AMOUNTS WERE OBSERVED OVER COASTAL SECTIONS BETWEEN THE
SMITH RIVER BASIN SOUTH TO THE EEL RIVER BASIN. TOTALS IN THIS AREA
WERE FROM 1.00- TO 3.00-INCHES WITH A FEW WETTER LOCATIONS IN THE
SMITH AND LOWER KLAMATH RIVER BASINS...AS WELL AS IMMEDIATE COASTAL
LOCATIONS FROM CAPE MENDOCINO TO NORTHERN MENDOCINO COUNTY WERE
BETWEEN 3.00- AND 4.50-INCHES.

FOR THE UPPER KLAMATH RIVER BASIN...DRIER LOCATIONS WERE IN THE
RANGE OF 0.33- TO 0.67-INCH WHILE AT THE CREST OF THE SOUTHERN
OREGON CASCADES TOTALS RANGED FROM 1.50- TO 3.00-INCHES.

DOWN INTO THE SHASTA LAKE DRAINAGE...TOTALS RANGED FROM 1.00- TO
LOCALLY 2.00-INCHES. JUST BELOW THE DAM NEAR REDDING AMOUNTS WERE
JUST OVER 1.00-INCH. THE REST OF THE SACRAMENTO VALLEY WAS SHADOWED
BY THE COASTAL MOUNTAINS AND AMOUNTS WERE IN THE RANGE OF A FEW
HUNDREDTHS OF AN INCH TO ALMOST 0.25-INCH.

FOR THE RUSSIAN/NAPA RIVER BASINS...PRECIP WAS JUST GETTING STARTED
WITH THE COLD FRONT TOWARD THE END OF THE HYDROLOGIC DAY. AMOUNTS
WERE IN THE RANGE OF 0.25- TO 0.50-INCH.

ACROSS THE SIERRA THE FEATHER RIVER BASIN RECORDED AMOUNTS OF 0.50-
TO 1.00-INCH...WHILE DROPPING SOUTH TOWARD THE AMERICAN RIVER BASIN
TOTALS WERE GENERALLY 0.10- TO 0.25-INCH. PRECIP REACHED JUST SOUTH
OF LAKE TAHOE BY 4 AM ON THE 22ND.

FINALLY FOR NE CA AND NW NEV THE TOTALS WERE A FEW HUNDREDTHS TO
ALMOST 0.25-INCH AT THE LOWER ELEVATIONS AND 0.50-INCH AT THE
WETTEST LOCATIONS IN THE WARNER MOUNTAINS.


.METEOROLOGICAL CONDITIONS (SAT AM - FRI AM)...

COLD FRONT IS DROPPING SOUTH ACROSS NORTHERN CA AND NORTHERN NEV
THIS MORNING...APPROACHING THE I-80 CORRIDOR THIS MORNING.
ASSOCIATED MOISTURE PLUME IS FOCUSED ON THE SF BAY AREA INLAND
TOWARD THE NORTHERN/CENTRAL SIERRA ACCORDING TO LATEST BLENDED TPW
IMAGERY. LOOKING AT GPS-MET IPW SENSORS ACROSS NORTHERN CA...PLACES
LIKE SHASTA DAM...CORNING AND PT ARENA HAVE PEAKED AND ARE SHOWING A
DECREASES IN AVAILABLE MOISTURE OVER THE PAST COUPLE HOURS. A TAD TO
THE SOUTH...LOCATIONS LIKE PETALUMA...DIXON AND COLFAX ARE REACHING
THEIR PEAK (BETWEEN 1.1- AND 1.4-INCHES). HEAVIEST PRECIP IS FALLING
WITH THE PRECIP BAND ASSOCIATED WITH THE COLD FRONT. 22/12Z KREV
RAOB IS SHOWING 700-MB WINDS FROM THE WSW AT 45-KT...AND THIS IS
PROVIDING OROGRAPHIC ENHANCEMENT TO THE PRECIP ON THE WEST FACING
SLOPES OF THE SIERRA. PRECIP GAGES SINCE 22/12Z SHOW AMOUNTS BETWEEN
0.25- AND 0.50-INCH (LOCALLY TO 0.75-INCH) FROM THE FEATHER RIVER
BASIN TO JUST SOUTH OF LAKE TAHOE. SNOW LEVELS AHEAD OF THE COLD
FRONT ARE RUNNING QUITE HIGH WITH THE 22/12Z KOAK RAOB RECORDING A
FREEZING LEVEL OF 11100-FEET. INLAND THE SOUNDING AT KREV AT THE
SAME TIME SHOWED 9500-FEET. LOOKING AT WEB CAMS...ITS TOUGH TO FIND
ANY THAT ARE SHOWING SNOW FALLING. LOOKS LIKE THERE COULD BE A FEW
WITH SNOW MIXING IN WITH THE RAIN AT ABOUT 8000-FEET.

BEHIND THE COLD FRONT...SHOWERS ARE MOST NUMEROUS ALONG THE COAST
FROM CAPE MENDOCINO NORTHWARD AND INLAND OVER THE UPPER KLAMATH
RIVER BASIN. THIS IS CLOSEST TO A FAIRLY BROAD S/WV TROF MOVING
ONSHORE ACROSS THE PACNW. THERE HAVE BEEN SOME LIGHTNING DETECTED
WITH THE STRONGER CELLS...BUT SO FAR MUCH OF THIS ACTIVITY HAS BEEN
OVER THE OREGON COASTAL WATERS AND IMMEDIATELY INLAND. WITH LESS
AVAILABLE MOISTURE BUT MORE FAVORABLE DYNAMICS...STILL EXPECTING
WIDESPREAD PRECIP OVER NORTHERN AREAS NEAR THE CA/ORE BORDER THROUGH
THE MORNING AS THE S/WV TROF MOVES INLAND.

FOR THE AFTERNOON HOURS...THE MOISTURE PLUME WILL SINK SOUTH TOWARDS
CENTRAL/SOUTHERN CA. MID-LEVEL FLOW WILL BECOME LESS FAVORABLE WITH
700-MB WINDS BECOMING MORE NWLY. THIS WILL SLOW DOWN THE OROGRAPHICS
MACHINE OVER THE SIERRA. THIS IS DUE TO THE S/WV TROF MOVING INLAND
TOWARD NORTHERN NEV AND THE OFFSHORE UPR RIDGE BEGINNING TO BUILD.
BEST PRECIP WILL BE FOCUSED ON THE CENTRAL SIERRA...AND INLAND OVER
NE NEV. THE FLOW TURNING TO THE NW WILL ACTUALLY BE MORE FAVORABLE
FOR THE HIGHER TERRAIN ACROSS NE NEV THAT RUNS FROM SW TO NE. THE NW
FACING SLOPES (INCLUDING THE RUBY MOUNTAINS) WILL SEE THE BEST
PRECIP AMOUNTS DUE TO THIS SET UP. SHOWERS OVER THE CA/ORE BORDER
REGION WILL BE ON THE DECREASE DURING THE AFTERNOON AS THE S/WV TROF
MOVES INLAND AND THE UPR JET STARTS TO LIFT NORTH AND PUSHES INLAND
TOWARD NW NEV.

DURING THE EVENING HOURS...PRECIP WILL CONTINUE TO BE ON THE
DECREASE FOR MOST AREAS. WITH THE NW FLOW ALOFT...THERE MAY BE SOME
LIGHT PRECIP AT THE SOUTH END OF THE SAN JOAQUIN VALLEY WHERE THE
TERRAIN ABRUPTLY INCREASES INTO THE SAN GABRIEL MOUNTAINS. A FEW
LINGERING SHOWERS MAY CONTINUE OVER THE SIERRA...THE CA/ORE BORDER
AREA...AND NE NEV.

OVERNIGHT...LOOK FOR PRECIP TO COME TO AN END. FOR NEXT
WEEK...PRECIP WILL BE SPARSE AS A FAIRLY STRONG UPR RIDGE SETS UP
JUST OFFSHORE. DISTURBANCES MOVING ON THE PERIPHERY OF THIS FEATURE
WILL BE TOO FAR NORTH AND EAST TO BRING ANY PRECIP TO THE REGION.
THE MODELS ARE HINTING AT THE NEXT OPPORTUNITY FOR PRECIP TO
POTENTIALLY MOVE IN ON FRIDAY. THERE ARE SOME TIMING DISCREPANCIES
WITH THE MODELS WITH THE EC BEING SLIGHTLY FASTER THAN THE GFS.


.HYDROLOGICAL CONDITIONS...

GOOD RAINFALL TOTALS OVER THE PAST 24 HOURS HAVE PRODUCED SOME
MODERATE RISES ALONG THE NORTH COAST OF CALIFORNIA.  THE SMITH RIVER
AT DR FINE BRIDGE AND THE MAD RIVER NEAR ARCATA BOTH CRESTED ABOUT 2
FEET BELOW MONITOR STAGE THIS MORNING. MINOR RISES ARE FORECAST FOR
POINTS FURTHER SOUTH ALONG THE NORTH COAST

THE UPPER SACRAMENTO IS ALSO EXPECTED TO RISE OVER THE NEXT 24 HOURS
IN RESPONSE TO RECENT RAINFALL.  RISES ARE EXPECTED TO BE MINOR AS
SOILS ARE STILL MOISTENING UP AFTER PROLONGED DRYNESS.

RAINFALL FORECAST FOR THE NEXT 24 HOURS IS ONLY EXPECTED TO PRODUCE
MINOR RISES IN NORHTERN CALIFORNIA WATERSHEDS.  DRY WEATHER OVER THE
NEXT 5-6 DAYS WILL ALLOW ALL RIVERS TO RECEDE TO BASEFLOW CONDITIONS.

ALL RIVER LEVELS ARE EXPECTED TO STAY BELOW MONITOR STAGE FOR THE
NEXT FIVE DAYS.


MORE INFORMATION ON THE CNRFC WEBSITE AT HTTP://WWW.CNRFC.NOAA.GOV

DRK/PF

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