Hydrometeorological Discussion
Issued by NWS California-Nevada RFC

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HYDROMETEOROLOGICAL DISCUSSION
NATIONAL WEATHER SERVICE / CALIFORNIA NEVADA RFC / SACRAMENTO CA
930 AM PDT WED APR 1 2015

...LIGHT PRECIP EXPECTED AT TIMES FAR NRN CA/NV AND SRN OREGON INTO
THE WEEKEND...
...POTENTIALLY WETTER SYSTEMS NRN CA/NV SRN OREGON EARLY NEXT WEEK...

.24 HOUR PRECIPITATION TOTALS (ENDING APR 1 AT 500 AM PDT)...

A WEAK TROUGH MOVED ONSHORE YESTERDAY MORNING WHICH BROUGHT A FEW
LIGHT SHOWERS TO FAR NORTHERN CA. PRECIP AMOUNTS WERE NEAR A
QUARTER INCH IN THE HIGHER TERRAIN OF THE SMITH BASIN. AMOUNTS
TAILED OFF QUICKLY FURTHER SOUTH TO JUST A FEW HUNDREDTHS ACROSS THE
LOWER EEL BASIN.


.METEOROLOGICAL CONDITIONS (SHORT TERM: WED AM - SAT AM)...

WV IMAGERY SHOWS A WEAK TROUGH OFF THE WEST COAST, AND MODELS SHOW
THE TROUGH AXIS SWINGING INTO NRN CA LATER TODAY.  AFTER A BRIEF
BREAK IN PRECIPITATION EARLY THIS MORNING, EXPECT SHOWERS TO DEVELOP
ACROSS FAR NRN CA/SRN OREGON BY LATER THIS MORNING AND THIS
AFTERNOON AND PERSIST INTO THIS EVENING NEAR AND AHEAD OF THE TROUGH
AXIS.  EXPECT A FEW SHOWERS OVER NRN NV LATER TONIGHT INTO THU AS
THE TROUGH SWINGS EAST INTO THE GREAT BASIN.  EXPECT WEAK RIDGING TO
TRAVERSE THE AREA THU NIGHT, KEEPING CONDITIONS DRY.  BY FRI NIGHT,
EXPECT A WEAK DISTURBANCE TO BRING A FEW LIGHT SHOWERS TO FAR NW
CA/SRN OREGON.  EXPECT FREEZING LEVELS 5000-8000 FT.


.METEOROLOGICAL CONDITIONS (LONG TERM: SAT AM - TUE AM)...

THE PERIOD STARTS OFF WITH AN UPPER LEVEL LOW CENTERED JUST OFF THE
BC COAST. A FEW LIGHT SHOWERS ARE POSSIBLE ACROSS FAR NORTHERN CA
AND SOUTHERN OR ON SATURDAY, BUT ANY PRECIP AMOUNTS SHOULD BE LIGHT.

BY EARLY SUNDAY, THE LOW WILL HAVE MOVED FAR ENOUGH SOUTH TO SET OFF
WIDESPREAD PRECIP ACROSS MUCH OF NORTHERN CA. WIDESPREAD PRECIP IS
EXPECTED ACROSS MUCH OF NORTHERN CA THROUGHOUT THE REMAINDER OF THE
FORECAST PERIOD AS THE LOW CONTINUES TO PROGRESS SOUTH THROUGH THE
AREA. CONSISTENCY MODELING THIS SYSTEM HAS BEEN LACKING, SO THERE IS
STILL QUITE A BIT OF UNCERTAINTY WITH THE FORECAST. CHOSE TO MAINLY
FOLLOW THE 30/00Z GFS THIS MORNING. AT THIS TIME, THE HEAVIEST
PRECIP LOOKS TO BE ALONG THE NORTH COAST AND THE NORTHERN AND
CENTRAL SIERRA, WITH THE MOST SIGNIFICANT WAVE OF PRECIP MOVING
THROUGH THE AREA LATE MONDAY NIGHT/EARLY TUESDAY MORNING. FREEZING
LEVELS WILL DROP SHARPLY SUNDAY MORNING ACROSS THE NORTH COAST AND
SIERRA TO AROUND 3,500-4,500FT. FREEZING LEVELS WILL REMAIN FAIRLY
LOW THROUGH MONDAY BEFORE RISING ON TUESDAY MORNING TO AROUND 5,000-
7000FT ACROSS THE NORTHERN AND CENTRAL SIERRA WHEN THE HEAVIEST WAVE
OF PRECIP IS EXPECTED TO MOVE THROUGH.


.HYDROLOGICAL CONDITIONS...

RIVER LEVELS ARE EXPECTED TO REMAIN NEAR PRESENT LEVELS ACROSS
CALIFORNIA AND NEVADA THROUGH THE WEEKEND.  MINOR RISES ARE FORECAST
FOR LATE SUNDAY AND MONDAY ACROSS NORTHERN CALIFORNIA AS SOME
RAINFALL MOVES INTO THE AREA.  ALL STAGES ARE EXPECTED TO REMAIN
WELL BELOW MONITOR LEVELS THROUGH THE WEEKEND.


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

MI/KL/MI/AM

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