471 FXUS66 KEKA 061348 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 548 AM PST Sun Nov 6 2022 .SYNOPSIS...A colder storm system will bring more rain, mountain snow and gusty southerly winds to the area Today. Rain and snow showers are expected to continue Monday and Tuesday. Drier weather is expected by mid to late week. && .DISCUSSION...IR satellite imagery show a long wave upper level trough dropping south toward the Pacific Northwest. After a brief period of dry weather, a wetter pattern will continue today with another storm system approaching the region this morning. This will bring rain showers and mountain snow to Northern California. Southerly winds will increase quickly ahead of the front with gusts from 30 mph to locally as high as 40 mph over the exposed ridges over the ridges and coastal plain. Convective allowing models indicate a strong line of showers moving across the area early this afternoon in Del Norte county and spreading south through the late afternoon and evening. With 500 mb temperatures of -25C and boundary layer Cape around 100-300 J/kg, isolated thunderstorms and brief heavy downpours will be possible with it. The chance of thunderstorm also increase as the 500mb temperatures drop to -33C and the instability increase. Small hail looks fairly likely along the coast from late tonight through Monday evening. A Winter Storm Warning is in effect for Del Norte County for elevation above 3,000 feet, and for northern Humboldt and Trinity counties to above 3,500 feet. Snow levels will be 3,500 to 4,000 feet with much of this initial round of rain. Later in the evening and overnight snow levels will fall to around 2,500 to 3,500 feet. Late Sunday night there may be a brief break in the precip before the upper level trough starts to move onshore bringing showers to the area. Snow levels will generally be around 3,000 feet and amounts may be more variable. These showers are expected to be most numerous in Humboldt and Del Norte counties.These showers are expected to be most numerous in Humboldt and Del Norte counties. A winter weather advisory may be needed for the snow on Monday and Monday night...and a another winter storm warning may be needed once again for Scott Mountain Summit late Monday night and Tuesday monrning.These showers will be fairly convective. The showers activity is expected to quickly dissipate on Wednesday as a shortwave ridging start to build over the West Coast, and the upper level trough progresses eastward. This will yield in a drying and clearing trend through Thursday. A cooler/drier airmass with clear skies will result in a threat for frost and freezing temperatures for the coastal Del Norte, Humboldt and Mendocino counties, as well as valleys of SW Humboldt and SW Mendocino counties on Thursday morning. These areas have not seen a widespread killing freeze yet this Fall. Thus, freeze warnings and frost advisories will still be issued for all this areas until experience a season ending killing freezing. Friday or Saturday the next system is expected to move into the area, although there is still a lot of uncertainty on the potential for precipitation. && .AVIATION...Light showers will develop this morning in advance of the next strong front. A convective line of showers with gusty winds, brief heavy rain and possibly thunder will then approach the coast early this afternoon. Southerly winds will be quite gusty ahead of and along the front, with high-res guidance mixing down brief gusts up to 40kts along the potential squall line. Expect conditions to quickly deterioate to IFR today with the front, followed by lowering ceilings throughout the day from MVFR to IFR as rain continues. && .MARINE...Another round of southerly fresh breezes return today. Model soundings are indicating that this front is much more unstable/convective than our usual fronts, so expect gusty southerlies ahead of the front this morning along with blustery westerlies in its wake this afternoon and evening. Some high resolution model guidance is indicating sparse isolated gusts in the 30 to 40 kts range, particularly in the northern waters right as the front moves moves onshore from late this morning to early in the afternoon. Additionally, a solid mid period swell will start to build in tonight and Monday peaking 16 to 18 feet at 15 seconds Monday evening. Current guidance remains right on the threshold of haz seas, but offshore buoys have confirmed modeled heights so current thinking is that this will remain just shy of the 18 ft seas criteria. This swell will then slowly decay into mid next week. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... Winter Storm Warning from 11 AM this morning to 4 AM PST Monday for CAZ102-105-107-108. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 3 AM PST Tuesday for PZZ450-470- 475. Small Craft Advisory from 9 PM this evening to 3 AM PST Tuesday for PZZ455. && $$ 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