Hydrometeorological Discussion
Issued by NWS California-Nevada RFC

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AGUS76 KRSA 281733
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HYDROMETEOROLOGICAL DISCUSSION
NATIONAL WEATHER SERVICE / CALIFORNIA NEVADA RFC / SACRAMENTO CA
930 AM PST SAT FEB 28 2015

...SHOWERS THROUGH THE WEEKEND AND WRAPPING UP ON MONDAY...

.24 HOUR PRECIPITATION TOTALS (ENDING FEB 28 AT 400 AM PST)...

AN UPR LOW DROPPING TOWARD THE REGION BROUGHT PRECIP TO PARTS OF THE
REGION YESTERDAY. HEAVIEST AMOUNTS WERE OBSERVED OVER THE NORTHERN
AND CENTRAL SIERRA WITH 0.25- TO 0.75-INCH (LOCAL 1.00-INCH)
AMOUNTS. THE SOUTHERN SIERRA SAW A BIT LESS WITH 0.10- TO ALMOST
0.25-INCH IN PLACES. PRECIP FOR THE SMITH AND KLAMATH RIVER BASINS
GENERALLY RANGED FROM 0.10- TO 0.50-INCH WITH THE WETTEST PLACES
ALONG THE COAST AND THE CREST OF THE SOUTHERN OREGON CASCADES.
FINALLY...THE NORTHERN HALF OF NEVADA SAW SCATTERED AMOUNTS WITH
SOME AREAS NEAR A FEW HUNDREDTHS OF AN INCH TO THE WETTEST LOCATIONS
REACHING 0.50-INCH.


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

CURRENTLY...AN UPR RIDGE RESIDES OFFSHORE ALONG 140W WHILE AN UPR
LOW SINKS SOUTH FROM THE PACNW TO NORTHERN CA. PLENTY OF AREAS OF
SCATTERED SHOWERS ROTATING AROUND THIS FEATURE WITH PRECIP GAGE AND
RADAR DATA SHOWING THE MOST CONCENTRATED AMOUNTS OVER THE
CENTRAL/SOUTHERN SIERRA...COASTAL SECTIONS FROM THE MONTEREY BAY
AREA SOUTHWARD...AND PORTIONS OF NEVADA.

THROUGH TODAY...LOOK FOR THE UPR LOW TO DROP TOWARD THE SOUTH AND
EVENTUALLY SLOW ITS FORWARD PROGRESS AROUND PT CONCEPTION ON SUNDAY.
BEST OPPORTUNITY FOR PRECIP TODAY WILL FALL OVER THE SOUTHERN 2/3 OF
THE REGION WITH A FOCUS ON THE HIGHER TERRAIN. MOISTURE CONTINUES TO
BE A LIMITING FACTOR...SO AMOUNTS ARE NOT EXPECTED TO BE
OVERWHELMING. PW VALUES FROM THE 28/12Z RAOBS INDICATE PW VALUES IN
THE RANGE OF 0.25- TO 0.50-INCH FOR A MAJORITY OF THE AREA. THE ONLY
EXCEPTION IS EXTREME SOUTHERN CA...WHERE THE KNKX RAOB IS SLIGHTLY
HIGHER AT 0.75-INCH. THIS AREA SHOULD SEE A DECREASE IN AVAILABLE
MOISTURE THROUGHOUT THE DAY AS THE UPR LOW DROPS SOUTH...PUSHING THE
SLIGHTLY HIGHER MOISTURE CONTENT AIR OVER NORTHERN BAJA.

FOR SUNDAY...PRECIP WILL GENERALLY BE OVER THE SOUTHERN HALF OF THE
REGION WITH THE GREATEST AMOUNTS COASTAL SECTIONS BETWEEN SAN
BERNARDINO AND SAN DIEGO COUNTIES...AND THEN INLAND TO THE NE OVER
THE SE CA DESERTS AND EXTREME SOUTHERN NEV. THE ORIENTATION OF THE
UPR TROF WILL BE POSITIVELY TILTED...NE-TO-SW. THIS WILL ALLOW
MOISTURE TO BE DRAWN ACROSS THE AREA WITH PW VALUES BETWEEN 0.50-
AND 0.75-INCH.

ON MONDAY...ANOTHER S/WV TROF WILL DROP TOWARD THE REGION FROM THE
NORTH. LOOKING AT WV IMAGERY...THIS SYSTEM CURRENTLY SITS OVER
WESTERN ALASKA AND BEGIN TO DROP SOUTH ALONG THE WEST COAST
TOMORROW. THIS SYSTEM DOESN/T LOOK AS IMPRESSIVE AS THE CURRENT UPR
LOW MOVING THROUGH THE AREA. LOOK FOR ANOTHER ROUND OF PRECIP FOR
THE AREA...FOCUSED ONCE AGAIN OVER THE HIGHER TERRAIN AND COASTAL
SECTIONS BETWEEN THE SF BAY AREA AND THE US/MEXICO BORDER.

FINALLY BY THE MIDDLE OF THE WEEK...THE UPR RIDGE WILL NUDGE CLOSER
TO THE COAST. THIS WILL BRING DRY CONDITIONS TO THE REGION ONCE
AGAIN FOR THE TUE THROUGH THU TIME PERIOD.


.HYDROLOGICAL CONDITIONS...


IN GENERAL..EXPECT LITTLE CHANGE TO RIVER CONDITIONS DURING THE NEXT
FEW DAYS IN WATERSHEDS AFFECTED BY THE CURRENT WEATHER SYSTEM.
NOTICEABLE SMALL RISES ARE EXPECTED ON SEVERAL OF THE COASTAL
DRAINAGES IN THE SOUTH COAST REGION.  ALL STAGES ARE EXPECTED TO
REMAIN WELL BELOW MONITOR LEVELS.


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

DRK/AT

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