439 
fxus66 keka 211203 
afdeka 


Area forecast discussion...updated 
National Weather Service Eureka California 
403 am PST Sat Nov 21 2009 


Synopsis...another disturbance will bring more rain and higher 
elevation snow to northwest California tonight into Sunday. Warmer 
and dry weather is expected for early next week. 
&& 


Discussion...isolated shower activity will continue to diminish this 
morning as short wave ridge moves over the region. The lull in 
precipitation will be brief as another system moves towards the Pacific northwest late 
tonight. Models continue to show main bulk of energy remaining well 
north of County Warning Area...but precipitation may be enhanced overnight as a jet maximum tracks 
over the Orca border. Models in good agreement with quantitative precipitation forecast totals of 
0.25 to 0.75 inches in Mendocino County with totals around 1 to 1.5 
inches in del Norte County. Snow levels around 2000 to 2500 feet this 
morning will rise today as warm air advection develops across the region. Expect 
snow levels to increase to 5500 to 6000 feet across the region before 
precipitation begins tonight. Locally lower snow levels down to around 3000 
feet are expected in the more sheltered valleys in east Humboldt and west 
Trinity counties where it can be difficult to mix in warm air. 


The longer term forecast shows the Sunday storm moving inland fairly 
rapidly Sunday night...with an upper ridge developing over the east Pacific 
by Monday. A short wave trough on Monday will try to break down the 
ridge but the effect should remain well north of the County Warning Area. Upper 
ridging will then return for Tuesday and Wednesday. Model 
consistency is surprisingly good through early Tuesday...with 
GFS...European model (ecmwf) and Canadian in fairly close agreement in strength and 
placement of features over the eastern Pacific/Gulf of Alaska 
region. More significant differences begin to appear on 
Wednesday...as the models work on bringing another strong low 
through the Gulf of Alaska. The indications are that a cold front 
associated with the low will swing across the Pacific northwest and 
northern California Thursday into Friday. The GFS may be slowing 
down the timing with successive runs...so will need to keep an eye 
on model timing and consistency for the Holiday time period. CMC/British Columbia 
&& 


Marine...winds have eased this morning but will increase again 
later today across the waters...with the highest winds in the northern 
portions. This is a result of a Post frontal trough sweeping through 
the area. Winds are expected to remain below gale criteria...but 
will be high Small Craft Advisory. Seas are currently in Small Craft Advisory level and should remain 
there. However there is the chance of some larger swell making it 
into the far northern waters. This combine with the increased wind waves 
could generate a hazard sea conditions in the wake of the trough. Winds 
will taper quickly behind the trough as high pressure builds over the 
area. Seas will taper into Sun night. All warnings/advisories will be 
done by Sun night. Early next week looks to be below Small Craft Advisory winds and 
borderline Small Craft Advisory for seas. The next sig front will hold off until 
Thanksgiving night or into Friday. Bfg 
&& 


Aviation...showers continue to pass through the coastal regions 
yielding IFR this morning and will maintain similar through the day. 
The trough approaching the region will bring increasing winds 
tonight with a slight increase in the risk of showers. IFR will 
generally rule for the next 24 hours with a few hours during midday that 
may reach MVFR. Uki is in the fog this morning and will remain such 
until after sunrise. While IFR dominate currently...by daybreak 
conditions should move into VFR. Clouds will increase and lower tonight 
as a weakening trough approaches the southern Mendocino County area. A 
few showers will accompany this trough early Sun morning causing MVFR. 
Bfg 
&& 


Eka watches/warnings/advisories... 
hazardous seas watch for sun for pzz470 
Small Craft Advisory for pzz450-455-470-475. 
&& 


$$ 


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