Area Forecast Discussion
Issued by NWS Eureka, CA
FXUS66 KEKA 242239
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
339 PM PDT MON OCT 24 2016
.SYNOPSIS...Rain showers will continue to diminish overnight.
Mostly dry during the day on Tuesday. Rain will return Tuesday
night...along with gusty south winds. The period of wet weather will
then persist through the end of the week.
.DISCUSSION...Satellite imagery shows a well developed low pressure spinning off
the coast of Oregon today. The associated weather front wrapped
around the center of the low about two loops. The warm, cold, and
dry conveyor belts associated with this mature low show up nicely on
the water vapor imagery. This afternoon, the weather front is slowly
pushing through NW California. Gusty south winds of 20 to 30 mph
with occasional higher gusts were observed in the area. Around one
inch of rain fell across NW California. This afternoon, radar
imagery is showing some convective shower just off shore from
Humboldt and Del Norte counties, behind the main weather front.
These showers should gradually diminish this evening into the
overnight hours as the front continues to push inland.
Rain showers will be in store for the area on Tuesday. A warm front
will push north across the area Tuesday night, bringing in another
round of rain. Then on Wednesday, a NE-SW oriented front will
straddle across the area, and this will bring in an extended period
of wet weather to NW California. With an upper level trough setting
up shop over the East Pacific, this is going to promote SW-ly
onshore flow for NW California. This will allow subtropical moisture
to stream into the area. With this pattern, confident that it will
be an extended wet period. However, confidence is low in the timing
and intensity of individual systems. /RCL
.AVIATION...Periodic MVFR ceilings and vsbys in light to moderate
rain will persist into the evening hours at all terminals.
Conditions should gradually improve at the coastal terminals
overnight and Tue as southeasterly winds produce some drying in the
boundary layer. Conditions for the interior valleys will probably
deteriorate overnight as trapped moist air leads to IFR or LIFR
conditions by daybreak.
.MARINE...Large westerly generated by a potent storm offshore
the Pacific Northwest will arrive tonight. The periods with the
incoming swell will be short and seas will be steep to very steep.
It will be very close to our criteria for a Hazardous Seas Warning.
Seas will remain hazardous through Tuesday and Small Craft
Advisories are in effect. Another low pressure system will begin to
take shape on Tue. Southerly to southeasterly winds will start to
increase as early as Tuesday afternoon. Winds will likely reach GALE
around mid to late evening Tue, primarily in the outer waters. Gale
force winds may also occur inside 10nm, though confidence is not
high at this time for the inner waters especially north of the Cape.
It will probably howl around Cape Mendocino, however there will be a
strong easterly component and winds may not reach GALE nearshore or
at the beaches and headlands.
The models continue to indicate broad low pressure lingering
offshore through the remainder of the week and winds will favor a
southerly or easterly direction. The GFS and ECMWF both indicate
another low impacting our waters Fri into Sat. There is considerable
uncertainty regarding the track of the low and the strength of the
NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory until 9 PM PDT Wednesday for PZZ450.
Gale Watch from Tuesday evening through Wednesday morning for
Small Craft Advisory until 8 PM PDT Tuesday for PZZ455-470-475.
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