Special Marine Warning 21, NWS Eureka, CA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
337 PM PST Mon Feb 19 2024

.SYNOPSIS...Gusty winds and locally heavy rain from showers and
thunderstorms will continue through this evening. Showers will
continue tomorrow with lighter winds and lighter rainfall. By
Wednesday, showers are expected to taper off with dry weather
forecast for the middle to end of the week. Occasional light rain
is possible toward the end of the week and into the weekend.

&&

.DISCUSSION...Satellite currently depicts a broad area of low
pressure continuing to spin off the Coast of California this
afternoon. Many thunderstorms have occurred throughout the day mostly
around southwestern Humboldt and the Mendocino Coast due to enhanced
instability. Shower activity will continue as the low pressure system
stalls off the coast through the night. The main threat with these
storms will be locally gusty winds. Gusts up to 60 mph are possible
with the strongest storms. In addition to the locally higher winds
around the showers and thunderstorms there will be winds of 50 to 70
mph on the ridges and exposed headlands. The high wind warning and
wind advisory remain in effect to highlight this. There have already
been many gusts in the 60 to 70 mph range with one gust recorded at
88 mph near Buckingham Park in Lake County. These showers have
already bought locally heavy rainfall which has caused minor
flooding, mostly for areas of Lake County which will continue through
tonight. A Flood Advisory is currently issued for southern Lake
County as a result. Into tomorrow, the upper level low off the coast
will slowly drift north. This will allow winds and shower coverage to
diminish. There will likely be an uptick in showers tomorrow
afternoon, but the overall wind field will be much lighter.

Occasional showers are expected to continue into Wednesday as the low
gradually moves off to the north. The showers will continue to
diminish in coverage and will mainly affect Humboldt and Del Norte
counties. However, there may be an increase in shower activity over
the interior. Some areas may see fog by Wednesday morning if
sufficient clearing occurs.

By the middle of the week, a brief period of high pressure is
expected to build into the region. By the end of the week and into
the weekend, ensemble clusters are generally showing an upper level
low approaching the California Coast. As a result, rain could be a
possibility again by the end of the week or into the weekend. The
placement of the low pressure system in relation to the region is
important in determining impacts, so more details will come in the
upcoming days. /MKK /JLW

&&

.AVIATION...Scattered thunderstorms with locally heavy downpours
are continuing to traverse NW CA this afternoon as an area of low
pressure spins offshore. Ample instability, LL wind shear and BL
moisture advection have provided conditions conducive to convection
throughout the CWA. All terminals are predominantly VFR and MVFR,
with ceilings and viz dropping briefly to IFR with intermittent
convective showers. Strong southerly winds and storm force gusts are
expected to continue through this evening and late tonight as
another surge of enhanced CAPE and convective storms develop along
the NorCal coast. Coastal stations will be most susceptible to 20-30
mph gusts through tomorrow morning, while winds in UKI will
diminish. MVFR ceilings will begin to lift late tomorrow morning as
the low weakens and moves north.

&&

.MARINE...Steep and hazardous waves resulting from persistent
southerlies and storm force gusts are being observed across the
waters this afternoon, especially in southern zones, as a prominent
low spins offshore. Anomalous CAPE values approaching 500 J/KG and
strong LLWS have led to several marine weather statements being
issued this morning for convective storms, with more likely to
follow. After a brief lull, unsettled conditions will continue
through this evening and overnight as convective showers are
reinvigorated with additional shortwaves. Prevailing winds will
continue to diminish overnight in the southern waters, but will
remain elevated in northern zones and areas near Cape Mendocino
through tomorrow afternoon. A long period swell will fill in Tuesday
afternoon alongside a decaying mid-period swell as sig wave
heights decrease. Another broad area of low pressure is forecast
to approach the PNW late this week, but winds currently seem less
impactful.

&&

.HYDROLOGY...Moderate, with brief periods of localized heavy,
rainfall will continue through today with more showers possible
tomorrow. As a result, a rapid rise on main stem rivers, small streams,
and creeks are expected. There is also a risk for minor flooding
of urban areas and ponding of water due to the high rain rates. A
Flood Watch is currently issued for most of Humboldt, Southern
Trinity, Mendocino, and Lake counties to account for this. Also,
Flood Advisories are issued for southwestern Humboldt and southern
Lake counties for observed minor flooding from high hourly rain
rates. Water levels at Clear Lake have a 91% chance of exceeding
the monitor stage of 8 ft by early tomorrow afternoon. Clear Lake
is expected to peak at 8.27 ft causing minor flooding impacts near
the lake. Scotts Creek has surpassed monitor stage (9 ft) and is
forecast to peak at 12.42 ft by this evening. /JLW

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Wind Advisory until 4 AM PST Tuesday for CAZ101>103.

     Flood Watch through Tuesday morning for CAZ103>106-108>115.

     High Wind Warning until 4 AM PST Tuesday for CAZ104>106-108-
     114-115.

     Winter Storm Warning until 3 PM PST Tuesday for CAZ107.

     High Wind Warning until 10 PM PST this evening for
     CAZ109>113.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Gale Warning until 3 AM PST Tuesday for PZZ450.

     Gale Warning until 9 PM PST this evening for PZZ455.

     Hazardous Seas Warning from 9 PM this evening to 9 AM PST
     Tuesday for PZZ455.

     Gale Warning until 3 PM PST Tuesday for PZZ470.

     Hazardous Seas Warning until 9 AM PST Tuesday for PZZ475.

&&

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Preliminary Local Storm Report
National Weather Service Eureka CA
334 PM PST Mon Feb 19 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1200 PM     Non-Tstm Wnd Dmg 2 ESE Clearlake Riviera 38.94N 122.69W
02/19/2024                   Lake               CA   Utility Company

            Power outage effecting about 3000 customers.

&&

JHW

Preliminary Local Storm Report
National Weather Service Eureka CA
336 PM PST Mon Feb 19 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0200 PM     Non-Tstm Wnd Dmg 2 NNW Ettersburg        40.15N 124.02W
02/19/2024                   Humboldt           CA   Utility Company

            Power outages effecting about 1000
            customers.

&&

JHW

Preliminary Local Storm Report
National Weather Service Eureka CA
345 PM PST Mon Feb 19 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0344 PM     Landslide        3 WNW Salyer            40.91N 123.62W
02/19/2024                   Humboldt           CA   Public

            Landslide cover 299, road impassable.

&&

JHW

Preliminary Local Storm Report
National Weather Service Eureka CA
401 PM PST Mon Feb 19 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0400 PM     Landslide        2 ESE Dos Rios          39.71N 123.32W
02/19/2024                   Mendocino          CA   Dept of Highways

            Mudslide blocking highway 162 to Covelo.

&&

JHW

Preliminary Local Storm Report
National Weather Service Eureka CA
436 PM PST Mon Feb 19 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0435 PM     Landslide        1 N Redway              40.13N 123.82W
02/19/2024                   Humboldt           CA   Dept of Highways

            Landslide on highway near Redway.

&&

JHW

Preliminary Local Storm Report
National Weather Service Eureka CA
441 PM PST Mon Feb 19 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0440 PM     Non-Tstm Wnd Dmg 3 SSE Shively           40.40N 123.95W
02/19/2024                   Humboldt           CA   Law Enforcement

            Powerlines down over roadway.

&&

JHW