Area Forecast Discussion
Issued by NWS Eureka, CA

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FXUS66 KEKA 261143

National Weather Service Eureka CA
443 AM PDT Sun May 26 2019

.SYNOPSIS...Light rain will diminish early today, and most areas
will be dry during the afternoon aside from some isolated showers
and thunderstorms across eastern Trinity and Mendocino counties
late in the day. For Memorial Day, most areas will be warm and
dry, but once again isolated showers and a few thunderstorms will
be possible across Trinity and Mendocino counties during the
afternoon and evening.


.DISCUSSION...Light rain continues to fall across the northern two
thirds of the region as a potent upper level low passes by from
the north. The majority of this rain is falling across Trinity
county and interior portions of Humboldt and Del Norte counties,
with only a few light showers across Mendocino county. This rain
will gradually move south through the remainder of the morning, and
will mostly diminish before approximately noon, resulting in a
mostly dry but cool afternoon for most areas. Later in the
afternoon, some weak instability and a passing upper level impulse
may result in the regeneration of convective showers across
mountainous areas, particularly in northern Trinity and perhaps
eastern Mendocino counties. Instability will be greatest across
the Trinity Horn region, and a few weak thunderstorms will be
possible here. This activity will diminish late in the evening and
overnight tomorrow.

On Memorial day, weak northerly flow will remain across the
region, along with lingering low level moisture. While most areas
will remain dry aside from some coastal drizzle in the morning,
another subtle upper level impulse embedded within the northerly
flow will likely pass through the region, which may assist in the
generation of additional showers and perhaps a few thunderstorms
across Trinity and northeast Mendocino counties. Instability will
be weak due to the presence of poor mid level lapse rates, and
thus any storms that develop will likely not be particularly
strong. Otherwise, expect generally dry conditions with pleasantly
mild afternoon high temperatures.

For the remainder of the week, California will remain within a
regime of weak northerly flow as a broad upper level trough
remains largely parked across the great basin. While most of the
region will remain dry as a result, lingering high moisture
content and the passage of additional upper level impulses will
continue to result in periodic chances for isolated showers and
thunderstorms across the eastern mountains through the end of the
week. While there are some uncertainties regarding which days
present the best opportunities for these showers, at the present
time the next best opportunity appears to be Wednesday afternoon.
Again, these showers will generally be limited to the mountain
ranges of eastern Trinity and Mendocino counties, and the
remainder of the region will generally see dry and warmer
conditions through the end of the week. /BRC


.AVIATION...An upper-level low continues to meander down the
California coast this morning. Rain chances are mostly done for
both coastal terminals this morning, but chances will taper off
across all of the forecast area as the low continues to move
southward. VFR to MVFR conditions are expected along the coast
this morning and afternoon, with ceilings expected to gradually
come down through the day. Both statistical and model guidance
suggests IFR to LIFR ceilings will be possible tonight at both
coastal terminals with both indicating the development of marine
stratus. Statistical guidance depicts visibilities beginning to
lower near the end of the TAF period. Mostly VFR conditions are
expected across the interior, though low clouds will be possible
tonight across interior river valleys. Gusty winds will continue
through this morning at KUKI as the upper-level low continues to
move southward. Additionally, a period of gusty northerlies will
be possible this afternoon and evening at KCEC.


.MARINE...Strong northerlies are expected to weaken late this
evening over the coastal waters, with seas gradually coming down
through Monday morning. Calmer conditions will then briefly take
hold through Tuesday evening. Northerlies will increase across
mainly the outer waters late on Tuesday, with the strongest winds
expected to be in the southern outer waters. Winds are forecast to
remain elevated across the outer waters and near Cape Mendocino
through the upcoming week. Otherwise, a couple of west to
southwest swells will move through waters over the next week.


NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory until 3 PM PDT this afternoon for PZZ450.

     Small Craft Advisory until 3 AM PDT Monday for PZZ470.

     Small Craft Advisory until 9 PM PDT this evening for PZZ455.

     Gale Warning until 9 AM PDT this morning for PZZ475.



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