Area Forecast Discussion
Issued by NWS Eureka, CA

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FXUS66 KEKA 202254

National Weather Service Eureka CA
354 PM PDT Fri Oct 20 2017

.SYNOPSIS...A brief dry break this evening before rain moves back
into the area late tonight. Wet Saturday through Sunday, especially
for Del Norte County. Mendocino County should remain dry. Dry and
very warm weather will return to NW California for next week.


.DISCUSSION...Overnight, NW California received substantial wetting
rain. The windward slopes in Del Norte and Humboldt Counties saw 2+
inches of rainfall. Around Humboldt Bay, most areas saw around 1.5
to 2 inches of precipitation. Around 0.5 to 1 inch of rain fell in
Trinity and Mendocino County. For most of today, we have seen
showers on the diminishing trend. We will have a brief dry break
this evening as convective showers dissipated. However, the dry
break won`t last too long. We will have the next opportunity of
precipitation coming in late tonight as a warm front makes landfall
along the Pacific NW Coast.

There is a frost advisory in effect for interior Mendocino County.
850 mb temperatures are progged to be around 2 to 3 C overnight. If
there is enough break in the sky cover, the temperatures should drop
into the low to mid 30s, leading to patchy frost in the area. The
frosty conditions will be ending in the morning as cloud cover moves
into the area from the northwest.

Do expect the heaviest precipitation over Del Norte County.
Moderate rainfall rate will start around the morning hours, and
continue through the day on Saturday. By the evening, the showers
should be lighter. However, models are showing precipitation to
linger through the weekend, especially for Del Norte County.
However, models diverge on the rainfall amount over the weekend.
ECMWF suggests up to 3 inches of rainfall for Del Norte County,
while GFS suggests about 1 inch of rainfall. Mendocino County
should see little to no precipitation from this system, as the
rain will mainly impact areas near the Oregon border.

The advertised dry and warm weather for next week is still in store.
A strong ridge of high pressure will build along the West Coast, and
bring in much warmer and drier air to the area. Highs in southern
Mendocino County will see highs near 90 degrees.


MARINE...Large W to NW swell has peaked and will begin to
gradually subside late this afternoon and this evening. Seas appear
to be a bit slower to subside than forecast, so have extended the
Hazardous Seas Warning through 9 PM. This will need to be replace by
a strongly worded Small Craft Advisory thereafter to account for
residual swell in addition to increasing southerly winds by Saturday
morning. Occasional gale force gusts are likely, but more frequent
and higher gusts are forecast to remain mainly N of the marine area.
The High Surf Advisory will expire at 6 PM, and this timing should
be okay. After winds drop off on Sunday, N winds will increase early
next week. /SEC


A robust weather system moved across the region on Thursday into
early today, mostly impacting coastal airports (ACV & CEC) with
periods of moderate to heavy rains, IFR-LIFR VIS/CIGS, LLWS, gusty
winds, showers and at least a couple of T-storms. Rain also spread
into interior locations (UKI). Midday satellite and radar pictures
indicated showers continuing into the afternoon (confirmed also by
rain reports). The showers dropped CIGS/VIS occasionally into MVFR.
Conditions will improve into late afternoon. However, this scenario
will be brief as another weather disturbance will brush across the
region Saturday bringing some more rain to the TAF sites.


CA...High Surf Advisory until 6 PM PDT this evening for CAZ101-103-

     Frost Advisory from midnight tonight to 8 AM PDT Saturday for

NORTHWEST CALIFORNIA COASTAL WATERS...Hazardous Seas Warning until 9 PM PDT this evening for PZZ450-



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