Area Forecast Discussion
Issued by NWS Eureka, CA

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FXUS66 KEKA 241207 CCA

National Weather Service Eureka CA
507 AM PDT Wed May 24 2017

.SYNOPSIS...Warm temperatures will return today followed by a
gradual fall back to normal values late in the work week. Coastal
areas will remain more seasonal with morning clouds and afternoon
sunshine. Pop up showers will be possible over the mountainous
interior the next few afternoons with a slight chance for
thunderstorms this afternoon and evening.


.DISCUSSION...Temperatures across the interior today will be 5 to
12 degrees cooler than yesterday as the upper ridge breaks down.
Temperatures will continue to fall to near normal values through
the end of the work week as an upper low from the northwest slides
down the ridge and tracks eastward. The marine layer influence on
coastal locations will keep temperatures more seasonal through
the week with morning cloudiness and afternoon sunshine. For
today, however, north winds will help clear clouds northward of
Cape Mendocino this afternoon but the Mendocino coast will have a
harder time clearing. The past few days a coastal eddy has been
reinforcing the stratus along the Mendocino coast. Strengthening
winds offshore will only prolong this coastal eddy thus expect
persistence for this afternoon. Additionally, there will be a
slight chance for thunderstorms across the mountainous interior
this afternoon as a shortwave moves inland.

The upper level ridge will amplify again this weekend bringing a
gradual warmup back to around 10 degrees above normal early next
week. In addition to the gradual warmup, upper level shortwaves
will move over the area from the southwest on the eastern
periphery of a deep trough. This, in combination with the warm
temperatures across the interior, will support the potential for
mountain convection each afternoon beginning Saturday through mid
next week. There is potential that one or two of these days could
have scattered afternoon showers and storms depending on the
timing of the shortwaves moving overhead. /RPA/KML


.AVIATION...Coastal clouds cleared out during the afternoon and
evening along much of the Redwood Coast on Tuesday other than some
clouds around Humboldt Bay and the Eel River Delta. A more
substantial cloud bank lingered off the Mendocino Coast. Clouds
expanded over the near shore coastal waters and the immediate coast
during the evening hours Tuesday, with low ceilings and periodic
visibility reductions in fog affecting both KCEC and KACV. Expect
improvement in conditions during the mid to late morning. Clearing
may be more quicker and more substantial this morning due to the
fact that the coastal cloud strip is fairly narrow. In addition,
high resolution models indicate some downsloping and light offshore
flow will develop near KCEC. There will be a tight gradient of wind
speeds near the coast today. KCEC will see wind gusts to near 30
knots by late morning, while KACV gusts should top out closer to 20
knots. KUKI is expected to remain VFR with lighter winds near 10
knots. /SEC


.MARINE...N winds will continue to increase thru this evening as the
gradient between high pressure over the E Pacific and an inverted
inland trough tightens. Strong gales will develop over the N outer
waters today with occasional gusts to storm force. Gale force gusts
will also develop over a large portion of the N near shore zone.
Across the S outer waters, sustained winds will reach gale force in
the NW corner of the zone, but frequent gale force gusts should
eventually develop elsewhere in the zone.

Model data continues to indicate that the pressure pattern and
associated gradient will spare the S near shore waters headline
criteria winds or seas. However, winds and seas will be more
treacherous near Cape Mendocino, and this area has been highlighted
in the text of the Coastal Waters Forecast. There is uncertainty as
to whether the short period N wind waves generated will be able to
affect enough of this zone to warrant an advisory for seas at some
point. Headlines are basically unchanged from the previous package.
Winds will begin to decrease late tonight and Thursday with lighter
winds returning for the weekend. /SEC


NORTHWEST CALIFORNIA COASTAL WATERS...Gale Warning until 3 AM PDT Thursday for PZZ450.

     Gale Warning until 6 PM PDT Thursday for PZZ470.

     Gale Warning until noon PDT Thursday for PZZ475.



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