textproduct: Eureka

KEY MESSAGES

* A few light showers are expected this morning in Del Norte and northern Humboldt counties.

* Valleys of Lake county to see near freezing or freezing temperatures again this morning with foggy conditions in northern valleys.

* Minor coastal flooding expected through Thursday at high tide, mainly around Humboldt Bay.

SYNOPSIS

A weak front is expected to bring more light rain to Del Norte and northern Humbodlt counties Tuesday morning. Cool and mainly dry weather is expected Wednesday through Friday with another chance for light rain over the weekend. High tides this week are likely to cause areas of coastal flooding for certain areas around Humboldt Bay.

DISCUSSION

Clouds have formed in many of the valleys tonight and this is expected to keep the temperatures from getting too cold. The exception is Lake county where a frost advisory has been issued for the coldest valley floors. Early this morning, a frontal band of very light showers is moving overhead which could create some rain to areas north of Ferndale in Humboldt county and in Del Norte county. Rainfall amounts are expected to be less than a quarter of an inch and likely less than a tenth of an inch. Like Sunday's rain system, this rain is not expected to make it very far inland or south with Trinity, Mendocino and Lake counties remaining dry expect for some light drizzle making it to the highest elevations has clouds interact with the upper terrain. This rain and is expected to come to an end in the evening.

Wednesday through Friday, an upper level troughing pattern is expected to remain over the region, yet at this point the bulk of the weather systems (showers/wind/etc) are expected to remain north of the area. This could change and one of the weather systems could drop farther south bring some light rain to northern portions of the area. Without the major storm-like impacts, NW CA can expect high temperatures expected to remain in the 50s in the north and the 60s in the south. At this point, Wednesday looks like it will be the most likely to clear in Humboldt and Del Norte counties after valley fog burns off, although confidence still remains moderate on this.

The NBM shows that Saturday could be the next time northwest California may see rain, however probabilities for over a tenth of an inch remain around 25 percent or less. Next week, models are still showing the potential for heavier rain, but the ensembles generally show it now holding off until the middle of the week.

AVIATION

VFR is expected for another hour or so before a weak frontal band arrives over the area. Light rainshowers are possible over North Coast terminals possibly leading to MVFR or very brief IFR conditions. North winds fill in to the entire forecast area after this band passes overhead with light offshore winds this evening likely keeping terminals clear of cloud coverage. DS

MARINE

Throughout most of the marine zones, northwesterly winds will continue to increase throughout the rest of today with the winds turning more northerly by late tonight. Nearshore southerly winds from about Humboldt Bay north through the Del Norte Coast are anticipated to turn northerly by this evening. Northerly winds are forecast to increase more for the southern marine zones late Tuesday afternoon and into the evening bringing advisory level conditions. Steep seas will also develop in response. Various mid to long period swells are also expected to build in throughout the week. /JLW

COASTAL FLOODING

Water levels yesterday reached 9.1 ft above MLLW at the North Spit gauge. This high tide caused some minor flooding to low lying areas of King Salmon and the Arcata bottoms. High tides were enhanced an increased anomaly of 1.1 to 1.2 feet above the astronomical tides predictions. Local surge models shows a similar anomaly on Tuesday as light southerly winds are expected to persist north of Cape Mendocino through the morning. This means that with an astronomical high tide of 8.04 feet on Tuesday and adding on the anomaly, expect water levels to reach 9.1 or 9.2 causing slightly more flooding than yesterday. A coastal flood advisory has been issued to warn of this hazard.

Wednesday, northerly winds strengthen and expand north. This wind shift is more likely to diminish the anomaly or keep it steady, instead of increasing it. This day has the highest astronomical tide at 8.06 ft and will likely bring at least minor coastal flooding with a chance of moderate coastal flooding. Impacted areas are mainly around Humboldt Bay with little expected outside the bay unless there are large waves. Arena Cove is also expected to see water level reach the highest astronomical tide levels. Waves are only expected to be around 6 to 7 feet at 11 seconds likely limiting the impacts for the Mendocino coast at this point, yet it will continue to be monitored for any changes. DS

EKA WATCHES/WARNINGS/ADVISORIES

CA... Coastal Flood Advisory from noon today to 3 PM PDT this afternoon for CAZ103.

Frost Advisory until 9 AM PDT this morning for CAZ114-118- 120.

NORTHWEST CALIFORNIA COASTAL WATERS... Coastal Flood Advisory from noon today to 3 PM PDT this afternoon for PZZ415.

Small Craft Advisory from 3 PM this afternoon to 3 PM PDT Wednesday for PZZ455-475.