Hydrometeorological Discussion
Issued by NWS California-Nevada RFC

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AGUS76 KRSA 271531
HMDRSA

Hydrometeorological Discussion
National Weather Service / California Nevada RFC / Sacramento CA
830 AM PDT Mon Mar 27 2017

...EXITING STORM TO THE EAST TODAY...
...NEXT SYSTEM ARRIVES FROM THE NORTHWEST ON WED INTO THU...

.24 HOUR PRECIPITATION TOTALS (ENDING MAR 27 AT 500 AM PDT)...

A cold front and upper level trough brought precipitation to
Northern and Central CA and Northern Nevada in the past 24 hours.
0.4-1.25 in the Smith Basin and 0.75-1.2 in Shasta Drainage and 0.2-
0.7 for the Eel River Basin and 0.1-0.5 in the Upper Klamath Basin
and less than a tenth of an inch for the Northeast CA Plateau and
locally up to 0.25 in the Warner Mountains.  Up to a half an inch of
rain fell in the Russian river Basin tapering off to less than 0.25
inches around the Bay Area and south to the northern side of Point
Conception except locally up to 0.4 inches in the Santa Lucia
Mountains and in the Central Valley.  0.5-1.25 for the west slope of
the Northern Sierra and 0.25-0.75 for the Central Sierra and
tapering off to less than half an inch for the Southern Sierra and
the east side of the  Sierra.  Generally less than a tenth of an
inch fell over Nevada with local amounts over higher terrain up to a
third of an inch.

.METEOROLOGICAL CONDITIONS (SHORT TERM: MON AM - THU AM)...

Upr trof is currently moving across the region this morning with the
best precip downstream of this feature over eastern NV. One embedded
s/wv trof is moving toward southern NV...while another is over the
Pacific Northwest down toward the CA/OR border area. Scattered
showers over the crest of the southern OR Cascades and far northwest
CA are associated with this more northerly feature.

Through Monday...precip will taper off from west to east as the
entire upr trof slowly makes its way out of the area and forms a
cutoff low close to the 4-Corners region by early Tuesday. In this
system/s wake...look for drier northwesterly flow to develop on the
downstream side of an upr ridge centered to the southwest of the
area building toward the Pacific Northwest. This will bring dry
conditions to the region early Wednesday...when the next moisture
plume ahead of the next system reaches the Pacific Northwest. As the
s/wv trof crosses 130W and moves over the coastal waters...the
moisture plume will sink to the south and intersect the north coast.
This will bring light to locally moderate precip to the CA/OR border
area later Wednesday into early Thursday. By the end of the period
(30/12Z)...the offshore system will have reached the coast with its
base over the north coast...as it begins to dive toward the
southeast.


.METEOROLOGICAL CONDITIONS (LONG TERM: THU AM - SUN AM)...

A digging upper level trough moves southeast through the Pacific NW
and Nrn CA and into Nevada Thursday bringing precipitation to
Northern Ca and the Sierra and most of Nevada. Showers are expected
over Nevada on Friday (diminishing from West to east during the day)
with a closed low forming over Southern Nevada Thursday night and
moving to the four corners region on Friday. An upper level ridge
builds in behind the system bringing generally dry conditions to CA
on Friday and to Nevada Friday night. Saturday is expected to be dry
across the region. Although the 12Z EC wants to bring a weak wave
into the Pac NW and brushing far Nrn CA Late Saturday into early
Sunday.  The EC has varied with the timing of this wave with the 00z
run faster than the 12Z.  The 06Z GFS doesn`t have something until
Sunday and is farther North than the 00Z run.  Kept Saturday dry for
the current forecast.

.HYDROLOGICAL CONDITIONS...

Rivers along the north coast are experiencing some slight rises from
the rainfall last night and early this morning. Most of the
headwater basins in the area have peaked and will slowly recede
throughout the day.

Expect baseflow to remain high for the next 5 days across mountain
streams with some rises later this week as more low and mid-
elevation snow begin to melt. Flows will remain high on the Humboldt
with flood stages expected to continue on the lower half of the
river for the next 5 days. Stages will continue to slowly drop
throughout the week on the San Joaquin River as Friant continues to
cut back on releases.


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

HSO/DRK/HSO/MI

$$



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