Area Forecast Discussion
Issued by NWS Eureka, CA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38
FXUS66 KEKA 292301

National Weather Service Eureka CA
401 PM PDT Wed Mar 29 2017

Showers and higher elevation snow showers will persist through
mainly Thursday morning, before drier conditions return for the
weekend. However, a change in the weather pattern may offer
increased rainfall potential for portions of next week.


(Tonight through Thursday evening)

As a cold front crosses the region, shower coverage should increase
some overnight, with the highest rainfall amounts found over
interior portions of Humboldt and Del Norte counties. With the
resultant increased cloud cover, low temperatures tonight will be a
few degrees warmer than last night, with near seasonal values

Precipitation will become more showery while decreasing in coverage
on Thursday. Colder air aloft will briefly filter into the region,
dropping snow levels down to near 4000 feet. Precipitation amounts
will be light with mixing ratios averaging about 6:1. Still, a light
dusting on a few area passes can`t be ruled out. Otherwise, look for
decreasing cloud cover as we head through the day, with afternoon
highs topping out in the mid 50s to mid 60s, warmest across
Mendocino County. With mainly clear skies and light winds, some
frost may develop across portions of the interior Mendocino valleys
Thursday night/Friday morning.

Another forecast challenge will be the strength of the northerly
winds behind the front on Thursday and then again on Friday as high
pressure builds toward the coast. With northerly flow stacked up
from the surface to 500mb, there is a potential for breezy (15-
25mph) and locally windy (20-30mph) conditions at the coast.

(Friday evening through Wednesday)

The ridge will flatten out and weaken on Saturday in response to
another short-wave trough. The models continue to struggle on what
to do with this shortwave. The GFS continues to be the most bullish
with driving the shortwave through the ridge and generating showers
over the interior with daytime heating on Sunday. The ECMWF has the
trough developing farther east on Sunday with much less potential
for showers. For now will continue to maintain fairly low shower
chances considering the high level of uncertainty. Another front
should approach around mid next week and bring a new chance of rain.


A passing cold front will continue to result in light to
moderate rain across Humboldt/Del Norte counties through this
evening. This will result in oscillations between IFR and MVFR
conditions at CEC and ACV, both due to low ceilings and reduced
visibility, with occasional dips to IFR at CEC. UKI may see a few
very light showers, with a brief period of MVFR ceilings overnight
tonight. VFR conditions are expected to tomorrow morning at all
terminals, after perhaps some patchy localized fog in some areas.


A 10 ft...15 second northwest swell continues to be the
dominant wave group throughout the waters today as winds remain
mostly light. This swell will continue to propagate through the
waters over the next few days, gradually decaying as it does so.
However, while the northwest swell will gradually subside, winds
will turn to the north as a cold front passes, and will gradually
increase to around 15 to 25 kt by tomorrow morning. While there will
be minor fluctuations in wind speeds throughout the next several
days, this will more or less remain constant through late Monday,
allowing steep northerly seas to develop in addition to the decaying
swell. Meanwhile, another long period northwest swell will build
into the waters late in the weekend, further adding to the sea
state. The end result will be that combined wave heights will remain
in the 9 to 12 ft range through roughly Sunday, but with a mix of
periods ranging from 6 to 8 seconds out of the north, to 13 to 16
seconds out of the northwest. Seas will increase to 12 to 15 feet as
the previously mentioned larger swell builds early next week. /BRC


NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory until 9 PM PDT this evening for PZZ450-455.

     Small Craft Advisory until 3 PM PDT Friday for PZZ470-475.



Visit us at

Follow us on Facebook and Twitter at:

For forecast zone information
see the forecast zone map online: is the U.S. government's official web portal to all federal, state and local government web resources and services.