


Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
911 FXUS66 KEKA 272225 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 325 PM PDT Thu Mar 27 2025 .SYNOPSIS...Strong winds and waves of rain will continue to impact the are through the day with calmer winds but more consistent rain tonight. Conditions will briefly clear and clam Saturday but stormy conditions return Sunday and persist through most of the first week of April. && .DISCUSSION...A 985 mb Pacific cyclone centered offshore WA/OR coast continue impacting the Pacific Northwest and Northern California this afternoon. Doppler radar depict scattered to numerous showers moving northeast across the forecast area, with the bulk of the rain in Del Norte and Northern Humboldt. Very windy to strong southerly winds continue impacting the coastal headlands and exposed ridges. Although, this winds has peaked up this afternoon as a low level jet (925-850 mb) up to around 65 kts moves along the North Coast. Surface observations have reported gusts from 40 to 55 mph along the coastal headlands and exposed ridges, locally stronger over the more prominent higher terrain. Downsloping winds have been keeping the precipitation generally light for the lower elevations, with 0.15 to 0.30 around the Humboldt Bay as of 2PM local time. With winds gradually weaken this evening and tonight, periods of moderate to locally heavy rainfall are expected. For the interior, the trough is associated with only very marginal cold air, keeping snow levels above 4000 feet. While 6 to 12 inches is likely around Scott Mountain on Highway 3, not other travel corridor impacts are expected into Friday. A series of shortwaves trough embedded within the upper-level trough will moves across the area tonight through Friday night. Cold air aloft will promote enough instability for isolated low- topped thunderstorms development along the coast this evening through Friday. The greatest risk from thunderstorms will be lightning strikes and perhaps brief heavy rain. Progressive storm motions will also preclude any major concerns for flash flooding or debris flow. In addition, brief heavy downpours are expected with the stronger showers. Lingering showers will gradually to taper off Friday night into Saturday morning, with a brief shortwave ridge building in the wake of the upper-level shortwave trough. Cold overnight temperatures are expected for Friday night into Saturday, with low temperatures in the mid 30`s to low 40`s..while upper 20`s to low 30`s for Trinity County. For areas where skies clear out quickly, areas of valley fog are expected to develop Friday night into Saturday. Stormy weather will most likely return around Sunday. The system Sunday will be driven by a compact surface low that has show significant variability in models, though it is very unlikely to be as windy as the current systems. Rainy weather will continue through most of the first week of April. By early next week, the main impact concerns will shift from wind to rain. Saturated soils and weaker downsloping effects will both enhance precipitation potential. 3 to 5 inches of steady rainfall is most likely for populated areas through next week. Long range CNRFC guidance currently shows a roughly 20% chance of main rivers reaching flood stage by the end of next week. Additionally, snow levels will likely drop through the event, particularly in Trinity County. The possibility of impactful snow will have to be watched closely by mid next week. && .AVIATION...Aviation concerns/flight hazards across the region today are being significantly impacted. These weather hazards are associated with a very wound-up low off the Oregon Coast. The greater impacts are surface winds and above ground winds (925mb/~2000 feet AGL). Surface winds will increase as the pressure gradient gets tighter; the above ground winds will reach >60kts along portions of the Coast; and therefore promote the powerful threat of LLWS (low level windshear). Precipitation remained mostly light across the region through much of the day. However, another pronounced wave of rain and embedded showers began to intensify and spread across Humboldt and Del Norte Counties by mid afternoon. Strong winds have probably allowed most Cigs to stay VFR, but the growing rain spread is allowing Cig/Vis to dip into MVFR. Adverse weather is expected to continue a somewhat up/down, walloping pattern across the region through the next 24-36 hours. A slight chance of increased instability could even trigger some stronger convection. /TA && .MARINE...Winds are peaking this afternoon as a strong low spins off the OR/WA coast. Strong Gales approaching 40 knot gusts are being observed in the northern waters, with solid 30 to 35 knot Gale gusts in the southern waters. Already steep 10 to 12 foot short period waves are being further reinforced by a large 18-20 foot long period swell that filled into the waters late this morning. Combined seas approaching 20 to 23 feet will continue to produce steep and hazardous conditions even as Gales gradually push north and diminish late this evening. A High Surf Advisory will remain in effect through early Friday morning - see the Beach Hazards section for more detail. Gusty winds and steep seas will gradually diminish on Friday before a brief reprieve from advisory level conditions early this weekend. There is still uncertainty surrounding the track of a tight, fast moving low approaching the waters early Sunday morning. Depending on the strength and proximity of the low to the coast, low end Gales will be possible, especially in the outer waters. NBM still only has about a 30% chance of southerly gusts >34 knots by 11AM Sunday. This active pattern is expected to continue through mid-next week. && .BEACH HAZARDS...A large westerly swell is currently generating 22 to 24 foot beach oriented surf across area beaches. A High surf advisory will remain in effect through early Friday morning to account for these large breaking waves and wave runup, with elevated wave heights persisting through the day. Take extra care near shoreline/ water`s edge and remember to never turn your back on the ocean! && .EKA WATCHES/WARNINGS/ADVISORIES... CA... High Wind Warning until 11 PM PDT this evening for CAZ101. High Surf Advisory until 5 AM PDT Friday for CAZ101-103-104- 109. Wind Advisory until 11 PM PDT this evening for CAZ102- 104>106. Wind Advisory until 8 PM PDT this evening for CAZ103. Winter Weather Advisory until 8 AM PDT Friday for CAZ107. NORTHWEST CALIFORNIA COASTAL WATERS... Gale Warning until 9 PM PDT this evening for PZZ450-470. Hazardous Seas Warning from 9 PM this evening to 3 PM PDT Friday for PZZ450-470. Hazardous Seas Warning until 9 AM PDT Friday for PZZ455. Gale Warning until 3 PM PDT this afternoon for PZZ475. Hazardous Seas Warning until 9 AM PDT Friday for PZZ475. && $$ 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