075 FXUS66 KEKA 022302 CCA AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 226 PM PDT Thu Nov 2 2017 .SYNOPSIS...Light rain will develop along the coast and gradually spread inland tonight, followed by heavier rain and cooler temperatures on Friday. Saturday will be dry and cool, but more rain and mountain snow is expected Saturday night and Sunday. A brief break of dry weather will occur on Monday and Tuesday with the next round of rain moving in by the middle of the week. && .DISCUSSION...Satellite imagery shows a whole lot of moisture and low cloud across the state of California this afternoon eluding to the arrival of a deepening trough. Our radar hasn't caught any signals of rain yet but the ASOS and webcams around Crescent City are reporting drizzle or light rain. Most areas in Del Norte County should see steady rain fall later this afternoon with the rest of the CWA following late in the evening and into early Friday morning as a frontal system passes overhead. Del Norte and Humboldt counties will see the heaviest rain fall Friday morning while Mendocino and Trinity counties observe it Friday afternoon. After the front passes, precipitation will clear as drier air moves into the region. Temperatures will also be cooling in response to the frontal passage leading to snow levels dropping. There may be some snow accumulations near the top of Scott Mountain Pass on Highway 3; however, the cold air will likely not arrive in time to allow snow to accumulate on most of the other major passes of highways 299 or 36. Saturday morning will start off chilly but the question will be how chilly do our valleys get. Current thinking is that with all the rain we receive on Friday that valley fog will develop which should keep most valleys from freezing. Cool and and dry conditions are forecast for the rest of Saturday before the next system arrives Saturday night. Precipitation will once again start in Del Norte County and then spread south through the region Sunday morning and afternoon. Snow levels for this event are projected to be around 3000 to 3500 feet and as a result some of our passes such as Scott Mountain pass and points along Highway 36 from South Fork Summit to the Trinity/Shasta county line may see accumulating snow. The Scott Mountain pass will likely see 4 to 6 inches of total snow accumulations, while the other areas will only see an inch or two. Steady precipitation will give way to scattered showers Sunday evening, which will mostly dissipate by Monday. Monday and Tuesday look to be dry and cool at this point with wet weather returning by the middle of the work week. && .AVIATION...An approaching weather system has contributed to a deeper marine layer today. There have been PIREPS of tops to around 035-045 feet which allowed low Cigs and Vis to filter into interior Mendocino; UKI reported IFR-MVFR conditions through much of the day. North Coastal airports saw Cigs significantly lift from IFR-MVFR in mid-morning. Even so, fog and drizzle was frequent along sections of the Coast. By mid-afternoon, conditions continued to vary from IFR- MVFR at the coast and surprisingly even inland at UKI where local air traffic may have been significantly impacted. The rest of the period, models seemed to be a little conflicted with Cig forecast as the weather system and associated cold front moves toward the North Coast. The main band of rain will increase tonight starting at CEC and then steadily spread throughout the Region. However, mostly light sprinkles/rain can be expected in the far North Coast this afternoon. The associated frontal passage will impact the North Coast overnight...followed by post frontal disturbances throughout Friday. && .MARINE...Southerlies should increase a tad tonight. Winds will remain too light for an advisory. Winds should shift around to the N to NW after frontal passage on Fri, then remain northerly through Sat. Main concern will be a building short period NW swell Fri and Fri Night. It will be marginal for an advisory with heights around 8- 10 ft and periods near 12 seconds. For now, will hoist an advisory for hazardous seas for only the outer waters due to the short periods. Northerlies should increase a tad on Sat, before another fairly weak front moves across the waters on Sun. Winds overall with this front may be a wee bit stronger, but still not a major concern at this time. Models have been honing-in on a stronger front that will hit around mid next week. The GFS was faster than the ECMWF. Even though the forecast for Tue may appear rather pessimistic, the strong winds are not forecast to occur until late Tue night or early Wed. && .EKA WATCHES/WARNINGS/ADVISORIES... CA...None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 2 PM Friday to 2 AM Saturday for PZZ470. Small Craft Advisory from 5 PM Friday to 9 AM Saturday for PZZ475. $$ Visit us at http://www.weather.gov/eureka Follow us on Facebook and Twitter at: http://www.facebook.com/NWSEureka http://www.twitter.com/nwseureka For forecast zone information see the forecast zone map online: http://www.weather.gov/eureka/zonemap.png