251 FXUS66 KEKA 202255 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 355 PM PDT Thu Jun 20 2019 .SYNOPSIS...A dry upper trough passing through will maintain sunny and breezy weather for much of northwest California through Friday. Near normal temperatures in the interior today will warm slightly above normal this weekend before a more substantial cooling trend commences next week. && .DISCUSSION...Only minor changes were made to the going forecast package, with overall sunny, dry and breezy weather continuing through the weekend. An upper level trough passing southeastward across the Pacific Northwest has brought a cooler and drier airmass to our region today. Temperatures inland are running 10 to 15 degrees cooler than yesterday, and even a few degrees lower at the coast. The exception is along the Mendocino coast, where the coastal stratus has retreated to the south today, giving way to a bit more sunshine and milder temperatures. However, despite the sunshine today, many locations are feeling a cool breeze, thanks in part to the upper level trough passage, along with an increased pressure gradient toward the coast as thermal troughing has shifted back inland. Gusts along exposed portions of the coastal plain and over the hills and ridges into the 30 to 40 mph range have been common. This will continue to be the case heading through Friday, and while winds will relax a little through the weekend, it will remain breezy in exposed areas. Geopotential heights rebound slightly on Friday and temperatures should start to edge upward a bit in the valleys. Gusty winds will likely put a cap on afternoon highs again, however. Lows may start out "cool" Friday morning, in the lower to mid 40s in some of the colder valleys. Strong north winds will also make it miserable in the mountains, especially in the King Range where northerlies have been gusting to 55 to 63 mph for the last couple of days/nights. Medium range deterministic models and ensemble forecast systems continue to indicate a large trough dropping southward from the Gulf of Alaska next week. This trough will bring cooling to the interior. Highs inland will still be quite pleasant through, in the mid 70s to mid 80s in the interior valleys. Frost is not expected at this time for any of the interior valleys. Coastal areas may also start to see more cloud cover, though there is still a great deal of uncertainty regarding coastal stratus next week as northerly flow offshore decreases. && .AVIATION...Robust north winds persisted across the North Coast air terminals overnight through afternoon. Conditions are fairly unchanging through evening with CEC staying gusty and winds decoupling by late evening at ACV. With uncertainty, models indicating possible stratus returning in the morning at ACV. Stratus occurred in the far south Mendocino coast with the marine layer tops about 2000-2200 feet. Inland areas were VFR. A surge of stratus advected from STS-near the Mendocino border. && .MARINE...A large area of surface high pressure located over the NERN PAC combined with low pressure over CNTRL CA and the Great Basin continues to yield a tight pressure gradient over the coastal waters of NWRN CA. Gale force northerlies are occurring as a result over the EKA outer waters, and extending into portions of the inner waters. The pressure gradient is tighter closer to the coast today, allowing for stronger winds over the nearshore waters compared to the last couple of days. Whether there is enough coverage of Gale Force gusts over the inner waters for Gale Warnings is debatable, but either way these winds are producing hazardous seas which are propagating across the EKA inner waters. Model guidance indicates these conditions will generally continue through the weekend. Gale warnings have been extended through Saturday evening, and while there should be some modest improvement heading into Sunday, there may still be some gale force gusts over the outer waters on Sunday. Hazardous seas warnings for the inner waters may need to be extended into Saturday as well, with at least small craft advisory conditions lingering into Sunday there. Heading into next week it looks like winds and seas will finally diminish more significantly, especially north of Cape Mendocino. && .EKA WATCHES/WARNINGS/ADVISORIES... CA...None. NORTHWEST CALIFORNIA COASTAL WATERS...Hazardous Seas Warning until 11 PM PDT Friday for PZZ450-455. Gale Warning until 9 PM PDT Saturday 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