Hydrometeorological Discussion
Issued by NWS California-Nevada RFC

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AGUS76 KRSA 011727
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HYDROMETEOROLOGICAL DISCUSSION
NATIONAL WEATHER SERVICE / CALIFORNIA NEVADA RFC / SACRAMENTO CA
930 AM PST SUN MAR 1 2015

...SCATTERED PRECIP PRIMARILY OVER SOUTHERN HALF OF CA AND NEV...

.24 HOUR PRECIPITATION TOTALS (ENDING MAR 1 AT 400 AM PST)...

PRECIPITATION WAS MAINLY OBSERVED FROM THE I-80 CORRIDOR AND
SOUTHWARD ACROSS THE REGION.

FOR THE SIERRA...HEAVIEST AMOUNTS WERE OBSERVED OVER THE YUBA AND
AMERICAN RIVER BASINS WITH 0.25- TO 0.75-INCH. DROPPING SOUTH
THROUGH THE SOUTHERN SIERRA...AMOUNTS WERE GENERALLY FROM 0.10- TO
0.25-INCH.

FOR THE SF BAY AREA SOUTH TO THE CENTRAL CA COAST...AMOUNTS WERE
GREATEST IN THE SOUTHERN HALF OF THE AREA WITH 0.25- TO 0.75-INCH.
TO THE NORTH AMOUNTS WERE A FEW HUNDREDTHS TO 0.10-INCH.

FOR SOUTHERN CA...SCATTERED AMOUNTS RANGED FROM 0.10- TO 0.50-INCH
FOR THE HIGHER TERRAIN WITH 0.10- TO 0.25-INCH AT LOWER ELEVATIONS.

IN THE SAN JOAQUIN VALLEY...AMOUNTS WERE FROM A FEW HUNDREDTHS OF AN
INCH TO JUST OVER 0.10-INCH. BAKERSFIELD SAW THE MOST WITH 0.15-INCH.

FOR NEVADA...PRECIP FELL BETWEEN THE I-80 CORRIDOR AND US-6
CORRIDOR. TOTALS IN THIS AREA WERE FROM A FEW HUNDREDTHS AT THE
DRIER VALLEY LOCATIONS TO 0.33-INCH AT THE WETTER MOUNTAIN
LOCATIONS.


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

LATEST WV/IR IMAGERY SHOWS THE UPR LOW HAS DRIFTED SOUTH OVERNIGHT
AND IS NOW IN THE VICINITY OF SAN LUIS OBISPO. THE NEXT S/WV
TROF...WHICH WILL ACT AS THE KICKER FOR THE INITIAL SYSTEM IS
BEGINNING TO DROP SOUTH ON THE DOWNSTREAM SIDE OF THE UPR RIDGE
ALIGNED BETWEEN 140W AND 150W. THIS SECOND FEATURE IS CENTERED JUST
OFF THE NORTHERN BC COAST.

VERY SCATTERED SHOWERS ARE AFFECTING CENTRAL CA AND SOUTHERN NEV
THIS MORNING...WHILE THE MORE IMPRESSIVE PRECIP IS STREAMING INLAND
FROM SAN DIEGO COUNTY AND NORTHERN BAJA NE ACROSS IMPERIAL AND
RIVERSIDE COUNTIES BEFORE MOVING INTO NW ARIZ. THE ORIENTATION OF
THE UPR LOW AND ASSOCIATED FLOW AROUND THIS SYSTEM HAS DRAWN A PLUME
OF MOISTURE FROM THE LOWER LATITUDES AND IS ADVECTING THE HIGHER
MOISTURE CONTENT AIR TOWARD THE AREA WITH THE BEST PRECIP. 01/12Z
KNKX RAOB SHOWS A FAIRLY MOIST PROFILE FROM THE SFC TO 400-MB AND A
RECORDED PW OF 0.83-INCH. THIS IS +2 STANDARD DEVIATIONS AND BETWEEN
THE 75TH AND 99TH PERCENTILE. PERCENT OF NORMAL FOR THIS TIME OF
YEAR IS APPROACHING 175-PERCENT. SINCE 01/12Z...SAN DIEGO COUNTY HAS
SEEN THE MOST PRECIP WITH AMOUNTS RANGING FROM 0.10- TO 0.33-INCH IN
A 3-HOUR TIME BLOCK.

THROUGH THE REST OF THE MORNING AND AFTERNOON HOURS...THE UPR LOW
WILL CONTINUE TO SINK TOWARD THE SOUTH AND PASS PT CONCEPTION BY
02/00Z. THIS SHOULD ALLOW THE MOISTURE PLUME TO SINK SLIGHTLY TOWARD
THE SOUTH AND PUSH A BIT MORE INLAND OVER THE LOWER COLORADO RIVER
BASIN. THE MODERATE PRECIP OVER SAN DIEGO COUNTY SHOULD LIGHTEN UP
BY SUNSET.

FOR THE REST OF THE AREA ON SUNDAY...PRECIP WILL BE CONFINED TO
AREAS SOUTH OF I-80. LOOK FOR SCATTERED SHOWERS TO INCREASE IN
COVERAGE DURING THE AFTERNOON WITH DAYTIME HEATING.

MONDAY WILL SEE THE SECOND S/WV TROF DROP IN FROM THE NORTH...ACTING
TO EJECT THE INITIAL UPR LOW TO THE NE. THIS NEXT SYSTEM IS LOOKING
TO TAKE A FARTHER WEST TRAJECTORY...AND THE MODELS HAVE TRENDED IN
THIS DIRECTION OVER THEIR PAST FEW RUNS. THIS MAY INITIALLY KEEP THE
PRECIP OFFSHORE...LEAVING NORTHERN CA MAINLY DRY (EXCEPT FOR SOME
AFTERNOON SHOWERS OVER THE SIERRA). AS THE SYSTEM DROPS TOWARD
CENTRAL/SOUTHERN CA...PRECIP WILL INCREASE WITH WEAK TO MODERATE
ONSHORE FLOW. AMOUNTS LOOK TO BE LESS WITH THIS SYSTEM AS COMPARED
TO THE CURRENT ONE.

ON TUESDAY...THE SYSTEM WILL SWING EAST ACROSS NORTHERN
BAJA...ALLOWING THE AREA TO DRY OUT. THEN THROUGH THE REST OF THE
PERIOD...THE OFFSHORE UPR RIDGE WILL NUDGE TOWARD THE COAST. THIS
WILL WARM TEMPERATURES WITH DRY CONDITIONS.


.HYDROLOGICAL CONDITIONS...

PRECIPITATION DURING THE PAST 24 HOURS PRODUCED VERY SMALL RISES ON
SOME CENTRAL AND SOUTH COAST STREAMS AND RIVERS.  RIVERS IN THE
SIERRA NEVADA HAVE MORE OR LESS REMAINED STEADY.

SMALL RISES ARE FORECAST DURING THE NEXT COUPLE OF DAYS FOR SOME
STREAMS AND RIVERS IN THE SOUTH COAST REGION OF CALIF.  A MINOR RISE
IS FORECAST ON THE SAN DIEGO RIVER AT FASHION VALLEY TODAY.  ALL
STAGES ARE EXPECTED TO REMAIN BELOW MONITOR LEVELS.


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

DRK/AT

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