Weather Service Report


571 
FXUS66 KEKA 292301
AFDEKA

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

.SYNOPSIS...
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.

&&

.DISCUSSION...
.SHORT TERM... 
(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 
expected. 

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. 

.LONG TERM...
(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. 
/PD/DB

&&

.AVIATION...
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. 
/BRC

&&

.MARINE...
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

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...None.
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 http://www.weather.gov/eureka

Follow us on Facebook and Twitter at:
http://www.facebook.com/NWSEureka
http://www.twitter.com/nwseureka

For forecast zone information
see the forecast zone map online:
http://www.weather.gov/eureka/zonemap.png

Return to Home page


Western Regional Climate Center, wrcc@dri.edu