Area Forecast Discussion

KEY MESSAGES

* Some coastal drizzle possible Friday with more widespread light rain likely for Saturday.

* Briefly warmer, drier, and clearer conditions Monday and Tuesday.

* More and heavier rain possible beyond Wednesday but timing is highly uncertain.

SYNOPSIS

Mostly dry weather is expected to continue through Friday. A weak weather system is expected to bring some light rain on Saturday. Dry and warmer weather is expected Sunday through Tuesday with more rain possible Wednesday.

DISCUSSION

An upper level trough is continuing to gradually dip south along the Pacific Coast. The trough will continue to weaken north winds close shore Friday will also lifting up marine influence along shore. Very light drizzle will be possible along the North Coast Friday evening the marine layer lifts. Otherwise, the trough will continue to support cool and moist weather all across NW California.

A weak cold front will cross the area during he day Saturday. Only very weak south wind is expected ahead of the front. There is a broad 35% chance of wetting rain with the front across the area. Potential for more than 0.25 inches is less than 10%. Weak winds will make for little terrain enhancement overall. Snow levels are expected to be around 5,000 feet with this system making it one of the colder weather systems so far this season.

Sunday morning the rain is expected to come to an end. Widespread low clouds and possibly fog in the valleys is expected to keep the valleys from getting too cold Sunday morning,. High temperatures are expected to only be in the mid 50s to low 60s on Sunday. High pressure starts to build in on Monday and highs in the mid to upper 60s are expected in the interior. Shady areas will likely remain notably cooler. This warmer and dry weather is expected to continue into Tuesday. Nights will be chilly, especially Monday morning in areas that clear out with drier air behind the front. Tuesday morning may be warmer in some areas, but also drier and there may be less clouds around.

Wednesday and beyond is the next chance for rain. Ensemble clusters continue to show a strong signal of an atmospheric river pattern setting up November 4th and beyond with each day though the 11th having about a 30% chance of wetting rain. While the pattern has high confidence, timing remains very uncertain. Ensembles are starting to resolve a period of higher chances around next Friday with a 65% chance of wetting rain that day rather than 30%. Should an AR occur that day, potential for more than 1.0 inch of rain is around 20%. /JHW, MKK

AVIATION

A weak and ragged marine layer has continued to allow mostly VFR conditions again all along the coast. High resolution models suggest a roughly 35% chance of some IFR ceilings by sunrise. Light drizzle in a lifting marine layer may create periods of MVFR conditions Friday afternoon but others VFR conditions are expected to persist with a still inconsistent marine layer Friday night. /JHW

MARINE

Northerly winds have mostly died off with only isolated gusts now over 20 kts in the southern outer waters. steep short period seas are also quickly falling below 6 feet. By early Friday morning, seas will generally fall below 6 feet with gentle winds across the waters. Weak winds will persist into the weekend with some briefly southerlies possible Saturday as a front passes. Weak short period seas will allow minor west and southwest mid period swells to have more impact. Northerlies will slowly return early next week. A notable long period swell up to 7 feet at 18 seconds is on track to build in Monday. Though not particularly steep, this swell has the potential for increased sneaker wave risk and will need to be tracked closely. /JHW

COASTAL FLOODING

Water levels Thursday reached 9.0 ft above MLLW at the North Spit. This brought some minor flooding to low lying areas of King Salmon and the Arcata bottoms. This was with an anomaly of about 1.1 foot above astronomical tides. The surge models are showing a slightly higher anomaly during the high tide Friday (at 2:51 PM), and with an astronomical tide of 7.50 ft, this would again push levels around 8.6 or 8.7 ft, just shy of most coastal flood impacts. As such, an advisory has not been issued for the moment though conditions will be borderline.

EKA WATCHES / WARNINGS / ADVISORIES

CA... Frost Advisory until 10 AM PDT this morning for CAZ103-105- 106-110-111-114.

NORTHWEST CALIFORNIA COASTAL WATERS... None.