Hydrometeorological Discussion
Issued by NWS California-Nevada RFC

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HYDROMETEOROLOGICAL DISCUSSION
NATIONAL WEATHER SERVICE / CALIFORNIA NEVADA RFC / SACRAMENTO CA
920 AM PST SUN NOV 23 2014

...MAINLY DRY THROUGH MID-WEEK...
...PRECIP RETURNS LATER IN THE WEEK...

.24 HOUR PRECIPITATION TOTALS (ENDING NOV 23 AT 400 AM PST)...

PRECIP YESTERDAY WAS FOCUSED MAINLY ON THE NORTHERN HALF OF THE
REGION WITH THE BEST AMOUNTS OVER THE NORTHERN/CENTRAL SIERRA...AS
WELL AS NE NEV HIGHER TERRAIN.

FOR THE NORTHERN/CENTRAL SIERRA AMOUNTS WERE GENERALLY FROM 0.50- TO
1.00-INCH...BUT A FEW LOCAL AMOUNTS IN THE UPPER PORTION OF THE
AMERICAN RIVER BASIN REACHED 2.00-INCHES. PRECIP TRAILED OFF QUICKLY
TOWARD THE SOUTHERN SIERRA WITH A FEW HUNDREDTHS AT THE SOUTHERN END
TO JUST OVER 0.50-INCH NEAR YOSEMITE NP.

THE S/WV TROF MOVING INLAND FROM THE PACNW TOWARD NORTHERN NEV
BROUGHT LIGHT AMOUNTS LESS THAN 0.25-INCH FOR DRIER LOWER ELEVATIONS
WITH WETTER W TO NW FACING SLOPES BETWEEN 0.50- TO 1.00-INCH WITH A
FEW LOCATIONS IN NE NEV REACHING 1.50-INCHES.

COASTAL LOCATIONS VARIED FROM 0.10- TO 0.50-INCH BETWEEEN THE CA/ORE
BORDER AND THE SANTA LUCIA MOUNTAINS. HOWEVER...A FEW WETTER
LOCATIONS ACROSS THE SF NORTH BAY AND THE SANTA CRUZ MOUNTAINS DID
TOP OUT CLOSEER TO 1.00-INCH.

FOR THE CENTRAL VALLEY...TOTALS WERE ON THE LIGHT SIDE...FROM A FEW
HUNDREDTHS TO ALMOST 0.25-INCH.


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

YESTERDAY/S S/WV TROF MOVING FROM THE PACNW ACROSS NORTHERN NEV IS
NOW CROSSING THE SOUTHERN ROCKIES. ANOTHER S/WV TROF IS MOVING
INLAND ACROSS BC AND WA STATE. ALSO...AN UPR RIDGE IS CENTERED TO
THE SW NEAR 30N/130W. NEXT MOISTURE PLUME IS ON THE PERIPHERY OF
THIS FEATURE ADVECTING FROM JUST WEST OF HAWAII TO 40N/140W.
ALSO...A NARROW AREA OF MOISTURE IS CONVERGING ALONG A WARM FRONT
THAT WILL MOVE TOWARD SOUTHERN ORE AND NORTHERN CA LATER TODAY INTO
TOMORROW.

THERE ARE TWO CAMPS IN TERMS OF THE EFFECTS OF THE WARM FRONT AS IT
MOVES TOWARD THE COAST. THE 23/09Z SREF...23/12Z NAM AND THE 23/00Z
GEM DEVELOP SOME LIGHT PRECIP NEAR THE CA/ORE BORDER INTO TOMORROW
MORNING WITH THIS FEATURE...WHILE THE 23/00Z EC AND GFS (ALONG WITH
THE 23/06Z GFS BOTH ERODE A MAJORITY OF THE MOISTURE AS IT INTERACTS
WITH THE DRIER AIR OVER THE REGION AND KEEPS THE REGION DRY. FOR
NOW...LEANED TOWARD THE DRIER SOLUTION...BUT WILL CHECK THE 12Z
MODELS TO SEE IF ANY MODIFICATION IS NEEDED FOR THE AFTERNOON UPDATE.

UPR RIDGE WILL THEN DOMINATE THROUGH MID-WEEK AS IT STRENGTHENS AND
THE AXIS MOVES TOWARD THE WEST COAST. BOTH THE EC AND GFS BRING A
WEAKENING BOUNDARY TOWARD THE NORTH COAST ON THANKSGIVING WITH THE
FEATURE STALLING JUST OFFSHORE. SOME LIGHT PRECIP MAY REACH THE
CA/ORE BORDER AREA ALONG THE COAST...BUT MOST AREAS WILL REMAIN DRY
FOR THANKSGIVING. THEN A S/WV TROF WILL BEGIN TO MOVE TOWARD THE
WEST COAST ON FRIDAY INTO EARLY SATURDAY. THERE ARE SOME TIMING
DIFFERENCES...BUT LOOK FOR THE NEXT OPPORTUNITY FOR PRECIP ACROSS
THE REGION AT THE END OF THE WEEK. FOR NOW...USED A BLEND OF THE
23/00Z EC AND 23/06Z GFS.


.HYDROLOGICAL CONDITIONS...

RAINFALL OVER THE PAST 24 HOURS WAS CENTERED IN THE FEATHER, YUBA
AND AMERICAN WATERSHEDS.  MINOR RISES WERE OBSERVED IN THIS REGION.

THE UPPER SACRAMENTO RIVER ALSO HAD A MINOR RISE YESTERDAY IN
RESPONSE TO RAINFALL EARLY SATURDAY. BUT WITH CONTINUED RELEASE CUTS
FROM SHASTA THE RIVER IS EXPECTED TO QUICKLY RECEDE TO FLOW LEVELS
BELOW THOSE OF LAST WEEK.

DRY WEATHER OVER THE NEXT 5-6 DAYS WILL ALLOW ALL RIVERS TO RECEDE
TO BASEFLOW CONDITIONS.

ALL RIVER LEVELS ARE EXPECTED TO STAY WELL 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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