274 FXUS66 KEKA 121357 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 557 AM PST Tue Nov 12 2019 .SYNOPSIS...Dry weather will prevail through most of the week as a strong ridge offshore blocks storms from reaching Northwest California. A weak front will approach the North Coast early Friday and may generate light rain for mainly Del Norte and northern Humboldt counties. High pressure will quickly return Friday night and provide dry weather through the weekend. && .DISCUSSION...A shortwave trough moving into the Pacific Northwest this morning will flatten out our dominating ridge today. An upper level disturbance near 30N 140W has been generating considerable high level clouds offshore which will get caught up in the westerly flow and drift over the forecast area today. Granted it still looks like there will be a fair amount of sunshine through the high level clouds. In fact, temperatures will remain 10 to 20F degrees above mid November normals. Ukiah was one degree short of the record of 85F yesterday. We are once again forecasting a record high temperature of 80F today for Ukiah. Coastal areas have been struggling to reach 60F over the last several days due to the presence of a shallow marine layer and light winds with no mixing. Crescent City and Ft Bragg did hit the lower 60s yesterday while Eureka "warmed up" to 57F. NBM HIGH temperatures IN THE LOWER TO MID 60S for coastal sites that have been reporting mid to upper 50s for the last 8-10 days have been knocked down again. The upper low near 30N 140W will start to eject northeast on Wednesday in response to a vigorous upstream kicker. The GFS and ECMWF have been consistent with dampening out this wave considerably as it traverses across the area on Thursday. Low clouds and solid grey overcast skies will probably push into the coastal river valleys on Thursday as the marine layer deepens in response to this shortwave trough. It has been about 5 weeks since we last received rain. Oh granted there has been a few spats of drizzle too. It isn't looking like the incoming front will generate very much rain at all. Certainly, Del Norte and northern Humboldt counties could see at least a few hundredths early Friday morning. The deterministic global models are still indicating that the front will dissipate offshore before reaching the North Coast. There just isn't any mid level support to propel the front into the area. The NAM and SREF are wetter and are handling the shallow moisture better than the GFS and ECMWF. Unfortunately, this will be a shallow drizzle front and wont provide any rain for other portions of the forecast area that have received little or no rain this Fall, like interior Mendocino and Trinity counties. The ridge aloft will rebound quickly Friday night and put us right back into another couple days of dry weather with warmer interior temperatures and breezy N-NE winds for the upper elevations and ridges. This of course will need to be monitored for possible fire weather concerns. Come early to mid next week, GFS, ECMWF, GEFS and NBM indicate another shortwave trough dropping down into the area for perhaps another chance of rain. I am reluctant to believe any of these models at this point. The GFS ensemble continues to indicate large spreads. Also, the GFS and ECMWF have been flip flopping around with each run. For now will lean toward the NBM as primary guidance. && .AVIATION...Coastal fog has once again spread inland overnight. Per ACV profiler and model data, the marine layer has deepened to over 1000 ft. In addition, IR satellite imagery indicates thicker high clouds over the area than on Monday morning. As a result, expect fog and low cloudiness to be slower to erode today and have included slower improvement in the latest TAF issuance. Low clouds and fog are expected to return tonight. VFR conditions will continue at KUKI. Winds will be light across the area. /SEC && .MARINE...Light northerly winds will predominate across the coastal waters into mid-week, with some flow reversal to southerly possible S of capes and points. The strongest winds will be near and downwind from Cape Mendocino, but even these winds are expected to remain below advisory criteria. Light winds will become southerly Wednesday through Thursday night ahead of a front, but speeds are expected to remain below advisory criteria. Winds will become northerly again by the weekend, with speeds finally approaching advisory levels across at least the S outer waters by Saturday afternoon. Sea states for the first half of the week will be dominated by a series of modest mid period NW swells. A longer period W to NW swell is forecast to arrive on Thursday at around 10 to 12 feet at 18 to 20 seconds. See the Beach Hazards section for more info. /SEC && .BEACH HAZARDS...Building large, long period W to NW swell will bring a threat for sneaker waves Thursday afternoon into Friday. Due to the generally light SE to S winds across the area, short period waves should be minimal. Will likely need to issue a Beach Hazard Statement either later today or tonight. /SEC && .EKA WATCHES/WARNINGS/ADVISORIES... CA...None. NORTHWEST CALIFORNIA COASTAL WATERS...None. && $$ Visit us at https://www.weather.gov/eureka Follow us on Facebook and Twitter at: https://www.facebook.com/NWSEureka https://www.twitter.com/NWSEureka For forecast zone information see the forecast zone map online: https://www.weather.gov/images/eka/zonemap.png