490 FXUS66 KEKA 102145 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 245 PM PDT Wed Oct 10 2018 .SYNOPSIS...Slightly cooler temperatures are expected today and tomorrow as a weak disturbance digs southward across the forecast area. East to northeast winds are expected through the weekend with high pressure forecast to dominate the area. Warm and dry conditions are anticipated across most of the interior through the middle of next week. && .DISCUSSION...Early afternoon satellite imagery shows high pressure still positioned over the northeastern Pacific. This feature is forecast to drift toward the West Coast as a weak disturbance digs southward across the area. As a result, temperatures are expected to be slightly cooler today and tomorrow across the interior. As the disturbance digs farther south, model guidance then develops into a low off the central California coast late on Thursday. This scenario will favor an offshore flow pattern, with winds expected to shift from northerly to easterly to northeasterly. Coastal stratus is expected to return tonight for portions of Humboldt county coastline north of Cape Mendocino before offshore flow firmly takes hold Thursday. Offshore flow could aid in keeping most of the coast and inland areas cloud and stratus free later in the week and into the weekend. Inland areas are expected to see cooler and drier conditions tonight and tomorrow night, which could lead to some areas of frost in some of the low valleys of Trinity county. A frost advisory remains in effect for these colder for tonight. Otherwise, mostly sunny and dry conditions are expected across the forecast area through the weekend. High temperatures for today and tomorrow are expected to be in the low to mid 60s at the coast and low 70s to around 80 across the interior. Friday will see temperatures begin to warm slightly across the interior with upper 70s to mid 80s expected and mid to upper 60s at the coast. Highs for the weekend will be mid 60s to around 70 at the coast and low to mid 80s across the interior. && .AVIATION...Cloud cover has generally cleared the region Wednesday afternoon due to the increasing influence of dry offshore winds over interior NRN CA and OR. Offshore winds will increase further late tonight into Thursday morning...which will continue to inhibit the potential for stratus and fog along the coast. The one exception may be a brief attempt at stratus/fog in the vicinity of Humboldt Bay near sunrise Thursday...however, KACV may be just north of stratus/fog development. In addition, a southerly surge of stratus may impact the far southern Mendocino coast late Wednesday night into Thursday morning. Otherwise, gusty north winds occurring along the coast Wednesday afternoon are forecast to dissipate near KACV after sunrise. As surface winds weaken, flow above the surface may be sufficiently strong for a brief period of enhanced low-level wind shear during the evening. && .MARINE...A strong expansive area of surface high pressure continues to reside over the northeastern Pacific Wednesday afternoon, while low pressure was located across AZ/NM. A tight pressure gradient exists between these two features over the coastal waters of northwestern California, though it has weekend sufficiently such that gale force northerlies have come to an end over the southern outer waters. Nevertheless, gusty north winds will continue through Thursday, which will promote steep seas. Thereafter, low pressure will develop offshore late in the week, which will aid in weakening wind speeds significantly. Otherwise, a mid period northwesterly swell will linger across the coastal waters during the next seven days. In addition, a southerly swell from 3 to 5 feet at 14 seconds appears to be on track today through the weekend. && .FIRE WEATHER...A weak disturbance will bring slightly cooler temperatures today and tomorrow across the interior. High pressure will then build into the area as a low forms off the central California coast. As a result, offshore flow is expected through the middle of next week with the strongest occurring Thursday night into Friday morning and again on Saturday night. Gusts to 30 mph are possible along exposed ridges of interior Mendocino, Humboldt, and Del Norte county. Poor RH recoveries are also expected across portions of the interior as warm and dry conditions persist into next week. && .EKA WATCHES/WARNINGS/ADVISORIES... CA...Frost Advisory from 2 AM to 9 AM PDT Thursday for CAZ107-108. NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory until 9 PM PDT this evening for PZZ450-455. Small Craft Advisory until 3 PM PDT Thursday for PZZ470-475. && $$ 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