Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
428 FXUS66 KEKA 231101 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 401 AM PDT Sun Jun 23 2024 .SYNOPSIS...Interior warm and dry conditions continue through Tuesday while marine stratus dampens coastal temperatures. An upper level disturbance mid-week will allow for relatively cooler temperatures through Thursday. Warming trend returns for this weekend into next week. && .DISCUSSION...Light northerly onshore flow behind a weak frontal boundary lends favor to marine stratus development on the north coast this morning, especially north of the Cape and into the Eel River Valley. Crescent City, Eureka and Fortuna have reported visibility`s <1 mile for the last several hours. This additional surge of moisture beneath a moderate marine inversion will likely delay clearing until early afternoon - HREF indicates 15-25% probabilities for light drizzle and minor precip accumulations along the Humboldt coast before NW winds increase and stratus scatters out. Gusts to 40 mph are likely along coastal headlands this afternoon as the thermal trough strengthens. Highest probabilities center around Cape Mendocino and Point St. George. Hot, summer-like temperatures are forecast for the interior today beneath a broad upper ridge over western CONUS. Widespread temperatures in the upper 80`s and low to mid 90`s expected, with NBM probabilities favoring highs exceeding 95 and approaching/reaching 100 degrees again in the valleys of Southern Mendocino, Lake and eastern Trinity counties. This pattern is expected to remain largely consistent, perhaps tamped down a few degrees for the start to next week, through Tuesday with daily surges in diurnally driven NW flow. Coastal highs will remain significantly dampened by daily marine stratus redevelopment. An upper level pattern change is expected Wednesday into Thursday as mostly zonal flow is interrupted by an upper level trough dropping into the PNW, inducing relative cooling of temperatures and slightly elevated westerly winds. NBM high temperature probabilities drop off significantly in the low 90`s for the interior valleys, especially on Thursday following a weak frontal passage. Long range models are hinting at potential precip in Humboldt and Del Norte counties in the wake of this front, although probabilities for measurable precip are quite low. Otherwise, 500 mb clusters are beginning to align in favor of relatively zonal flow turning over to broad ridging late next weekend, allowing for another warming trend. && .AVIATION...LIFR stratus and fog blankets the coast once again this morning. Fog is expected to lift and peel back to the immediate coast by early this afternoon, with VFR expected this afternoon for portions of the coast. Inconsistent IFR ceilings and visibilities will most likely start to return early this evening, likely dropping to LIFR late tonight. Otherwise, widespread VFR conditions will persist for the interior with normal summer conditions. && .MARINE...Northerly winds strengthen again today. This will bring gusts to 20 kts and above along with steep short period seas throughout all waters, with Gale Force gusts expected in the usual spots downwind of Cape Mendo and near Pt St George. Northerly winds will weaken during Monday, and by Monday evening only the southern waters are forecasted to support short period seas steep enough for a small craft advisory. Meanwhile a minor northwest swell of 5 feet at 11 seconds will fill in early Monday morning. Northerlies are then forecast to remain below 15 kt for most zones during midweek, aside from the persistent 15-20 kt northerlies expected directly downwind of Cape Mendo. Winds may strengthen again Friday into next weekend. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 3 PM this afternoon to 3 PM PDT Monday for PZZ450. Small Craft Advisory until 3 PM PDT Monday for PZZ455. Small Craft Advisory until 3 PM PDT Monday for PZZ470. Small Craft Advisory until 3 AM PDT Tuesday 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