Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 301035
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
335 AM PDT Tue May 30 2017

.SYNOPSIS...An upper trough of low pressure will maintain
the persistent marine influence along the coast while providing
clouds and isolated showers and cooler temperatures to much of NW
CA for the next few days.

.DISCUSSION...Pictures from space showing mid and high level
clouds in advance of an approaching upper level trough. Main
impacts of this feature will be a continuation of weak onshore
flow and the persistent marine influence. As is often the case
with these types of systems...it may provide enough mixing to
disrupt the marine layer and allow some sunshine to penetrate the
sun starved coastal areas of the last few days. Unfortunately
forecast models are not showing any strong indications that this
will be the case today. Perhaps on Wednesday as the trough axis
passes over the coast some improvement will occur. The trough will
also enhance isolated shower activity to both the coast and
interior areas. Due mainly to the enhanced cloud cover stability
and mid level cooling...parameters are not impressive thus there
is little chance of any lightning activity today...just showers.
This pattern will persist through much of the week...however as
we approach the weekend high pressure will begin to strengthen
off the coast. Northerly Winds will also increase in response to
the tightening pressure gradient allowing for more mixing which
will help to clear out the stratus. Much warmer temperatures are
expected across the interior with highs in the low to even
possibly mid 90s. Towards the end of the forecast period some
uncertainties exist as a weak trough moves towards the coast.
Current thinking is this system will have minimal impacts across
our area. jt/sc/wi

&&

.AVIATION...LIFR conditions along the coast and adjacent coastal valleys will
persist through the morning hours. Model guidance indicates a small
area of dry air may mix into the marine layer by late afternoon
allowing for some partial clearing at ACV and CEC. However, odds
still lean toward continued cloudy conditions today with
only improving visibilities and lifting ceilings through the day.

Locations with VFR this morning across the interior and the southern
Humboldt coast will remain VFR through the day with only cirrus and
a few cumulus expected over the mountains this afternoon. Most
interior valleys with cloud cover this morning will clear by mid to
late morning. /RPA


&&

.MARINE...LIFR conditions along the coast and adjacent coastal valleys will
persist through the morning hours. Model guidance indicates a small
area of dry air may mix into the marine layer by late afternoon
allowing for some partial clearing at ACV and CEC. However, odds
still lean toward continued cloudy conditions today with
only improving visibilities and lifting ceilings through the day.

Locations with VFR this morning across the interior and the southern
Humboldt coast will remain VFR through the day with only cirrus and
a few cumulus expected over the mountains this afternoon. Most
interior valleys with cloud cover this morning will clear by mid to
late morning. /RPA


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...None.
NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory until 5 AM PDT early this morning for
     PZZ455.

     Small Craft Advisory until 3 PM PDT this afternoon for PZZ475.

&&

$$

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