Hydrometeorological Discussion
Issued by NWS California-Nevada RFC

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AGUS76 KRSA 161628

Hydrometeorological Discussion
National Weather Service / California Nevada RFC / Sacramento CA
930 AM PDT Fri Mar 16 2018



A band of precip associated with a surface cold front and shortwave
aloft stretches from northern NV across the northern Sierra to the
central CA coast.  Additional showers are occurring further north,
especially on the north coast near the center of an stacked low
pressure system.  Expect precip to spread south through the day and
affect much of southern CA and NV by this evening and tonight.
Expect showers to persist into Sat with cyclonic flow overhead and a
shortwave moving into southern CA.  Heaviest precip through this
evening is expected in the Sierra with mainly light to possibly
moderate amounts associated with the front elsewhere.  Sun looks
mainly dry as the system moves east. Freezing levels are expected to
remain 2000-5000 ft in the northern two thirds of the area.  For
southern CA/NV, freezing levels 5000-8000 ft today should fall to
4000-6000 ft by Sat morning.


The work week begins with a s/wv ridge moving overhead...while a
deep upr low settles into place over the eastern Pacific west of the
CA coast along 140W. This will bring dry conditions to the region
for Monday into early Tuesday...as the area waits for the upr low to
begin to slowly make its way toward the coast...and moisture gets
drawn northeast from the lower latitudes to near central and
southern CA.

For being 5 to 6 days out...the models are actually in reasonable
agreement with the placement of the moisture plume with PW values
hovering near 1.25-inch intersecting the central and southern CA
coast...and the progression of the upr low toward the region. At
this time...thinking puts light precip along coastal locations
Tuesday afternoon into the evening hours...picking up in intensity
overnight into Wednesday with the heaviest amounts focused along
coastal sections between the Monterey Bay area down through the
central coast and across Santa Barbara and Ventura counties.
Inland...the entire west slope of the Sierra will once again see
moderate to heavy precip. Amounts in these areas are expected to
range from 1.00- to 3.00-inches with the southern Sacramento and San
Joaquin Valleys seeing 0.50- to 1.00-inch. Freezing levels will be
elevated with this system under a moist southwest onshore flow
regime. Along the I-80 corridor of CA look for 8000-feet...for
central CA 8500- to 9500-feet...and across southern CA 10000- to
11500-feet. This will initially bring primarily rain to a majority
of the river basins...except the high Sierra.


Most headwater basin have peaked this morning or will do so later
today. Expect rivers to recede slowly through the next few days as
precip begins to taper off over the weekend. Can`t rule out a few
small additional rises today with any locally heavy rainfall that
develops in the lower elevation basins.

Michigan Bar reached monitor stage again early this morning. The
river is currently near the crest and should begin to recede later
this morning into the afternoon.

Additional rises are expected towards the middle of next week as a
warm storm begins to impact the area. Expect additional rises on
area rivers, including higher elevation basins.

More information on the CNRFC website at www.cnrfc.noaa.gov



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