textproduct: Eureka

AVIATION...00Z UPDATE

Satellite imagery shows a bank of coastal cumulus clouds making for MVFR conditions at ACV. These clouds are expected to expand through the afternoon before dissipating in the evening. Sounding data shows a weak marine layer forming this evening possibly creating IFR conditions before clearing early Thursday AM. Winds will turn offshore late tonight through dawn, possibly keeping the marine layer away from terminals. Southerlies are still expected to increase tomorrow through the day with gusts up to 20-30kts possible late in the 00Z taf period. Expect SCT to BKN ceilings through the day tomorrow with VFR to MVFR conditions for coastal sites. Inland terminals will see VFR conditions with gusty southerly winds. Expect localized LLT on approach for all terminals tomorrow midday through Friday. DS

PREV DISCUSSION

/issued 153 PM PST Wed Nov 11 2026/

KEY MESSAGES...

* Dry and unseasonably warm weather forecast through midday on Thursday.

* Moderate to heavy rain and gusty south winds across much of the area throughout Friday.

* Very large surf Saturday with breaking waves over 25 feet is possible. This will increase beach erosion and possibly bring some coastal flooding.

* Additional rain and wind possible over the weekend and into early next week.

SYNOPSIS...Unseasonably warm and dry weather is expected today and Thursday. Friday, a strong cold front is expected to bring gusty winds and moderate to heavy rain to the area. There may be a brief break in the rain on Saturday before another system brings more rain and wind Saturday night and Sunday.

DISCUSSION...A brief period of high pressure will continue for Northwest California through mid Thursday. Dry air and warmer than average conditions will continue as a result. There is over an 80% chance of high temperatures over 65 degrees along the Mendocino Coast again Thursday with over a 70% chance of high temperatures over 65 degrees along the Humboldt and Del Norte Coast. Offshore flow has aided in increasing high temperatures along the coast today. Interior valley temperatures will range from the low 70s to high 70s. Also, early morning low clouds/fog can be anticipated through this time period for moist interior valleys, as well as a general marine layer along the coast overnight/early morning that will clear and scatter by the afternoon. Tonight and into Thursday morning, a weak front is anticipated to approach the area. Some models show this front bringing isolated light showers or sprinkles to coastal areas.

By late Thursday, a cutoff low pressure system will approach the Pacific Northwest. Models also depict a troughing pattern lasting through early next week with a potential for multiple rounds of rainfall and strong southerly winds. Widespread rainfall and gusty winds are expected for Northwest California, as a result.

With the first front, southerly winds are anticipated to ramp up by Thursday evening with models indicating rain beginning very late Thursday night or very early Friday morning. The winds will likely be strongest just ahead of the heavier rain. The strongest winds are forecast for Del Norte County along with the King Range in Humboldt County. The GFS and the RRFS both show 55 to 65 kt at 925 and 850 MB as the front moves into Humboldt and Del Norte counties. Lower levels could be unstable enough to enable the higher winds to mix down to the lower elevations, especially along the coast. NBM also indicates at least a 75 to 80% chance of 24-hour max wind gusts of 45 mph or greater for Coastal Del Norte, along with coastal headlands and higher terrain areas of Humboldt and Del Norte counties and higher elevations in extreme northeast Lake County on Friday. A Wind Advisory has been issued for Del Norte County and the higher terrain areas of Humboldt County. This may need to be expanded or upgraded. As of this afternoon, a High Wind Watch may be issued for coastal headlands and higher terrain areas of Del Norte County for Friday morning. Otherwise, also on Friday, there is a 65 to 70% chance of 24-hour max wind gusts of 35 mph of greater for more populated areas of coastal Humboldt along with higher terrain areas of Trinity, Mendocino and Lake counties.

Moderate to heavy precipitation is expected through the day Friday, with showers likely through Saturday and the potential for another bought of moderate rainfall on Sunday. Light rain will most likely start very late Thursday evening on the upslope areas, such as the south slopes of the King Range. The heavier rain is expected to begin a few hours before sunrise on Friday morning. The National Blend of Models (NBM) indicates over a 80% chance of 24-hour rainfall totals of 2 inches or more for Del Norte, Humboldt, northern and western Trinity, and northern Mendocino from 4am Friday (11/13) to 4am Saturday (11/14). A 65 to 85 percent chance for 1.5 inches or greater is expected during the same time period for eastern central Trinity, southern Mendocino, and Lake counties. The Humboldt Bay region could see slightly less total precipitation due to a rain shadow effect.

Showers are anticipated behind the front, especially in Humboldt, Del Norte and northern Mendocino counties. The heavier showers may bring close to an additional inch of rain with them. There is a potential for some thunder with these showers, as well. The NBM thunder probabilities have come down slightly, but are still around 15 to 20 percent.

Generally dry weather is expected on Saturday, although there may be some lingering showers. This will be short-lived, however, with the next weather system moving in Saturday night or Sunday. This one is expected to have lighter winds and rain, but still could see a half inch in Lake county to nearly two inches in the mountains of Humboldt and Del Norte counties. Drier weather is possible Monday and part of Tuesday with another system possible later on Tuesday. /JLW & /MKK

MARINE...Southerly winds continue across the waters this morning, but remain only around 10 to 20 kt. A northwest swell of 8 to 11 feet at 13 seconds continues to move through as well. The southerly winds are expected to increase slightly this afternoon, but generally remain around 5 to 15 kt in the southern waters and 15 to 20 kt in the northern waters through tonight. Thursday a weak front is approaching the area and is expected to 20 to 25 kt southerly winds to most of the area. A new northwest swell is expected to move in building waves slightly to 13 to 14 feet at 15 seconds.

A strong front is expected to rapidly increase winds across the area Thursday night and Friday. Gales are expected to start near or shortly before midnight in the northern waters and may expand into the southern waters towards morning. There is the potential for storm force wind gusts if the comes in on the stronger side of model guidance and this will need to be watched as it gets into range of the high resolution models. Saturday night into Sunday another system is expected to bring gales or near gales. MKK

BEACH HAZARDS...Just as these strong winds are diminishing on Friday afternoon a very large swell is expected. The wave model shows this building to around 25 feet at 18 seconds. This could lead to breakers around 30ft. A High Surf Warning has been issued north of Cape Mendocino from 1pm Friday (11/13) to 4am Sunday (11/15) and south of Cape Mendocino from 4pm Friday (11/13) to 4am Sunday (11/15).

COASTAL FLOODING...Water levels inside Humboldt Bay continue to run 1.5 to 2 feet over the astronomical tides. Winds will continue to be southerly which tends to increase water levels slightly. The max high tide is expected to drop each day through the end of the week and into the weekend, yet stronger southerly winds through Friday are likely to offset at least some of this decrease in max tide height. The water levels are expected to be slightly below 8.8 feet the next couple of days around high tide (11/12 @12:527pm, 11/13 @1:04pm, 11/14 @1:45pm).

EKA WATCHES/WARNINGS/ADVISORIES

CA... Wind Advisory from midnight Thursday night to 1 PM PST Friday for CAZ101>106.

High Surf Warning from 1 PM Friday to 4 AM PST Sunday for CAZ101-103.

High Surf Warning from 4 PM Friday to 4 AM PST Sunday for CAZ104-109.

NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until midnight PST Thursday night for PZZ450.

Gale Warning from midnight Thursday night to 3 PM PST Friday for PZZ450.

Small Craft Advisory from 9 PM this evening to 1 AM PST Friday for PZZ455.

Gale Warning from 1 AM to 3 PM PST Friday for PZZ455-475.

Small Craft Advisory until 10 PM PST Thursday for PZZ470.

Gale Warning from 10 PM Thursday to 1 PM PST Friday for PZZ470.

Small Craft Advisory until 1 AM PST Friday for PZZ475.