Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Eureka California
226 PM PDT Wednesday Oct 7 2015

Synopsis...dry and seasonably warm weather will persist in the
interior through Friday as high pressure aloft remains over the
region. Low clouds will likely persist near the immediate coast
for the next day or two...with some sunshine by each afternoon.


Discussion...high level cirrus clouds have been streaming over
most of northern California this afternoon although coastal folks would
not have seen them due to the current blanket of stratus hovering
around 1000 feet. An offshore trough west of 135w will continue
to dig on Thursday forcing an upper ridge to pump up over northern
California. With 500mb heights reaching 588dm+ expect interior
temperatures to increase several degrees on Thursday. The warming air
mass aloft should also smash the marine layer down to mean sea
level for perhaps shallow pockets of dense fog around Humboldt
Bay. The ridge aloft is expected to hold Thursday night and then shift
slightly to our east on Friday. A tropical storm system will be
absorbed into the North Pacific trough during this time frame. The
models remain in good agreement with keeping the plume of deep
layer moisture and the most rainfall offshore and well to our west
on Friday. 500mb heights will start to fall on Friday...however
with heights in excess of 580dm and lack of cold air advection to
drive the surface front to the coast...suspect any precipitation to be
really light and confined mostly to the coast. At the moment it
looks like the del Norte County coast stands the best chance of
seeing wetting rain (a tenth of an inch or more) late Friday night or
Sat. The rest of the coast may only see a few hundredths if any at
all late Friday night or Sat morning. A drying and warming trend is
expected Sunday into early next week as high pressure both near
the surface and aloft builds. Coastal stratus will most likely
form during the night and morning hours...however it should clear
out with daytime heating and mixing. Bfg/jt


Aviation...models are indicating low clouds to burn back to the
coast briefly before onshore flow brings the marine layer back
over the coastal plain this evening. So have indicated a brief
period of VFR this afternoon and early evening followed by
MVFR/IFR conditions at kcec/kacv. However, with a thiner marine
layer and near calm conditions will keep kuki VFR with low clouds
being restricted to the coast overnight. Mkn


Marine...conditions remain low over the northwest cal coastal waters this
today with observations showing winds 5 to 10 knots and seas around 3
feet. While sea heights are forecast to come up slightly tonight and
tomorrow, they are expected to remain 5 feet or under. Winds will
remain below about 10 knots through Thursday night. Winds are forecast
to increase slightly out of the south late Thursday into Friday as a
cold front clips the area while it lifts into the Pacific northwest. The
main story will be in the sea state as two swell will approach the
region late in the week. First, a broad area of low pressure over
the Gulf of Alaska is stirring up the waters, generating a westerly
swell that will impact northwest cal late in the week. Second, a
southwesterly swell will arrive concurrently, generated by the
tropical system oho. Swell heights are expected to reach around
10 to 12 feet at about 14 to 15 seconds Friday night into Saturday.
Seas are expected to pull back slightly next week, but will
steepen up due to increasing northerly winds. All told, areas
exposed to the southwest should prepare for potentially rough
conditions as we head into the weekend. Mkn/bfg


Eka watches/warnings/advisories...
Northwest California coastal waters...none.


Visit US at http://www.Weather.Gov/Eureka

Follow US on facebook and twitter at:

National Weather Service Glossary of Abbreviations