Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
031 FXUS66 KEKA 011237 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 537 AM PDT Wed May 1 2024 .SYNOPSIS...Sunny skies and gusty northerly breezes are expected today, especially for coastal areas of Mendocino and southwest Humboldt. A front will generate light rain for Del Norte and northern Humboldt Counties late tonight and Thursday. A much wetter and colder system will bring a chance for heavy rain and high mountain snow Friday night into Saturday. && .DISCUSSION...Another chilly start this morning with multiple interior stations in the lower to mid 30`s. In contrast, several stations in southern Lake were in the lower 50`s. Frost advisory for interior valleys of Humboldt, Del Norte and Trinity remains in effect til 8 AM. A few sites have already fallen to 32F or lower again. Northerly breezes continued overnight for the exposed ridges. Wind prone sites had peak gusts around 40 mph. So far NE winds across higher elevations in Lake County have not been as strong, gusting up to 32 mph. For coastal areas, gusty north winds are forecast to diminish some today except for SW Humboldt and Mendocino coasts where gusts 35 mph are likely (>60%) with daytime mixing. A frontal system will approach from the NW this evening and disrupt the surface pressure gradient north of Cape Mendocino. A shortwave trough moving over the top of a broad flat ridge on Thursday will generate an influx of moist air and light upslope precip. Highest amounts if forecast to occur in Del Norte and west facing aspects Del Norte and Northern Humboldt where HREF indicate 6 hourly amount up to 0.10in. A colder upper trough with higher influx of moisture will bring a threat of heavy rain rates Friday night. 6-hourly amounts may exceed 0.50-1.00 for Del Norte and northern Humboldt. 12-24 hour amounts of 1 to 3 inches are expected for interior Del Nort and Humbodlt. Even Mendocino and southern will get rain, perhaps 0.50-1.25 over 12-24 hours Friday night into Sat. Much colder temperatures with mountain snow are forecast by early Saturday morning above 4000 ft. Cold trough aloft will progress into the Great on Sunday. How fast this occurs remains uncertain and showers may linger into Sunday. Additional shortwave troughs in brisk NW flow aloft may generate more showers early next week, though stronger ridging from the SW may bring warming and drying. DB && .AVIATION...Mostly VFR conditions have persisted at the terminals tonight, with some brief drops to MVFR at ACV. Temporary drops to MVFR could continue this morning until solar radiation lifts any lingering clouds. VFR conditions will prevail today. Northerlies will continue to be gusty in the afternoon at all the terminals and diminishing by sunset. An approaching front will bring low clouds and rain to the coastal terminals tonight, diminishing conditions down to IFR or MVFR. UKI looks on track to stay mostly clear for the next 24 hours, but a low level wind shear threat is possible tomorrow night. JB && .MARINE...Gusty northerly winds tonight will continue through most the day. Gusts will be near or at gale force in the southern waters, particularly south of Cape Mendocino. Winds and waves will begin to diminish in the late afternoon in the northern waters. The southern waters will remain gusty through early Thursday morning. Aside from northerly breezes south of Cape Mendocino, winds and seas will subside Thursday. On Friday afternoon winds will shift increase and shift westerly as a front approaches, before turning northerly and increasing further Saturday. JB && .EKA WATCHES/WARNINGS/ADVISORIES... CA... Frost Advisory until 8 AM PDT this morning for CAZ102- 105>108. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 3 AM PDT Thursday for PZZ450-470. Gale Warning until 8 PM PDT this evening for PZZ455-475. && $$ 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