Cape Mendocino to Point Arena CA from 10 NM to 60 NM Marine Forecast
|Tonight...N Winds 20 To 25 Kt. Waves Nw 6 Ft At 5 Seconds. Patchy Fog.|
|Sun...N Winds 20 To 25 Kt. Waves Nw 6 Ft At 6 Seconds...And S 2 Ft At 15 Seconds. Patchy Fog.|
|Sun Night...Nw Winds 15 To 25 Kt. Waves N 7 Ft At 7 Seconds... And Nw 2 Ft At 12 Seconds.|
|Mon...Nw Winds 10 To 15 Kt. Waves N 6 Ft At 6 Seconds...And Nw 3 Ft At 11 Seconds.|
|Mon Night...Nw Winds 10 To 15 Kt. Waves N 6 Ft At 6 Seconds... And Sw 2 Ft At 19 Seconds.|
|Tue...Sw Winds 5 To 10 Kt. Waves Nw 4 Ft At 11 Seconds...And Sw 2 Ft At 18 Seconds.|
|Wed...Sw Winds 5 To 10 Kt. Waves W 7 Ft At 11 Seconds...And N 3 Ft At 18 Seconds.|
|Thu...Nw Winds 5 To 10 Kt. Waves W 13 Ft At 15 Seconds.|
| Area Forecast Discussion|
National Weather Service Eureka CA
258pm PDT Sat September 19 2020
Dry weather and seasonably warm temperatures will return today and last through much of next week before the next chance of rain arrives mid to late week.
A pleasant, mostly sunny day has unfolded as zonal flow developed in the wake of a passing trough. Dewpoints today remain elevated at lower levels with another day feeling somewhat humid outside. A drier air mass will briefly work in over the next couple of days. Some warming will continue this weekend with 850 mb temps climbing into the mid to upper teens Celsius by Sunday afternoon.
On Monday, the pattern begins to shift as a weak shortwave trough approaches. This disturbance should be mostly non-impactful other than dropping temperatures by a few degrees compared to Sunday, and possibly generating some patchy drizzle along the coast Monday night. This will be the first bit of energy that will be rotating in off a parent deepening trough to the north along the NEPAC. An associated front will approach the area overnight Wednesday ahead of the deepening trough. This will bring the first shot of light showers for northern Humboldt to Del Norte. Any light precipitation may be confined to Del Norte county.
Deterministic and ensemble guidance have been struggling to resolve the amplitude of ridging that will be south of trough as it attempts to deepen Wednesday night, or as late as Friday. Ensemble guidance favors higher 500 mb heigheights and a lower amplitude trough as of now, with GFS as more of an outlier. This outcome will greatly effect how much and where rainfall is seen. Quantitative Precipitation Forecast could potentially be on the lighter side and restricted from northern Humboldt to Del Norte counties. There is however good agreement on broad southwest flow beginning Wednesday to return the moist airmass, with a connection to anomalously high precipitable water values with this system. If the trough were to shift more favorably, there would be opportunity for some productive rain showers. Expecting continued variablilty in forecast solutions in the short term. /JW
North winds gusting from 20 to 30 kt are expected tonight through Sunday over the outer waters. Those winds will support the inherited small craft advisory. Winds are then forecast to weaken by Tuesday, with the strongest west-southwesterlies being confined to the Oregon waters through most of the week. Otherwise, model guidance shows a large northwesterly swell spreading from the Gulf of Alaska toward the coastal waters of northwest California during Thursday.
.EKA WATCHES/WARNINGS/ADVISORIES... CA...None. NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory from 3am to 7pm PDT Sunday for PZZ470.
Small Craft Advisory until 9am PDT Monday for PZZ475.