Area Forecast Discussion
Issued by NWS Eureka, CA

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FXUS66 KEKA 271109

National Weather Service Eureka CA
409 AM PDT Sun May 27 2018

.SYNOPSIS...Warm, dry and mostly sunny conditions can be expected
today through Tuesday in most areas, with breezy north winds near
the coast. Milder temperatures are expected Wednesday and beyond,
with an isolated shower or weak thunderstorm possible across the
taller interior mountain ranges late Tuesday through Thursday.


.DISCUSSION...A summer-like pattern is evolving across California
as a ridge of high pressure aloft gradually takes residence
across the West Coast. This building high pressure aloft will lead
to strong surface heating throughout the state, which in turn
will generate a classic "thermal low" pressure system in the lower
levels across California that will persist through Tuesday. The
primary impacts to our local weather will be three- fold.

First, temperatures across interior areas will increase
dramatically today through Tuesday, most notably in Trinity and
Mendocino counties. Afternoon highs are expected to reach well
into the upper 80s to low 90s across these interior valley
locations, and decrease gradually towards the coast where
temperatures will likely only be a few degrees above normal.
Second, northerly winds will increase significantly across the
waters, and this will lead to breezy conditions near the coast.
Finally, these stronger winds and a warmer and dryer airmass will
prevent stratus from becoming particularly widespread, with only a
few patches expected overnight in the typical trouble spots
around Humboldt Bay. Skies should be mostly sunny in the vast
majority of places through Tuesday.

Late Tuesday, a pattern change will begin across the West Coast
as the previously mentioned ridge of high pressure is gradually
replaced by a broad trough of low pressure aloft. As this occurs,
temperatures will cool back to near seasonal averages Wednesday
through the end of the week, perhaps even slightly lower than
normal on Thursday. Northerly winds will also gradually weaken
Thursday through the end of the week, and more widespread coastal
marine clouds will likely return as this occurs. In addition, A
few showers and perhaps a thunderstorm or two will be possible
toward the middle of the week across the taller mountain ranges of
Trinity and Mendocino counties, perhaps as early as Tuesday
afternoon but more likely Wednesday and Thursday
afternoon/evening. Conditions appear to be only marginally
supportive of thunderstorms though, and any storms that do develop
will likely be weak and isolated.


.AVIATION...Low stratus was occurring from Fortuna north to KACV
early Sunday morning. Model guidance indicates it will persist
through late morning, and then dissipate during the
afternoon...with a few patches of redevelopment possible tonight.
Elsewhere, clear skies were generally observed. However, fog can`t
entirely be ruled out in the vicinity of KUKI this morning.
Otherwise, north winds occasionally gusting in excess of 20 kt
will be possible along the entire coast this afternoon.


.MARINE...Surface high pressure located over the NERN Pacific
combined with increasing Central Valley heating/lower pressure
will yield a tight pressure gradient over the coastal waters
through midweek. As a result, northerly gales will be probable
over marine zones 470/475, with high end small craft wind speeds
expected over zones 450/455. In addition, localized wind
enhancement is likely in the vicinity of Cape Mendocino and Point
Saint George. Seas will continue to build into Monday, with outer
water wave heights ranging from 9 to 13 feet at 10 seconds, and 8
to 10 feet at 9 seconds near shore. North winds are forecast to
weaken Thursday and Friday as a weak frontal system breaks down
the area of high pressure. However, restrengthening is possible
going into next weekend.


NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory until 5 AM PDT Thursday for PZZ450-455.

     Small Craft Advisory until 5 PM PDT this afternoon for PZZ470-

     Gale Warning from 5 PM this afternoon to 5 AM PDT Thursday for



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