958 FXUS66 KEKA 150836 AFDEKAAREA FORECAST DISCUSSION National Weather Service Eureka CA 136 AM PDT Mon Sep 15 2025
.SYNOPSIS...A ridging pattern will bring scattered to clear skies and dry conditions with RH values in the teens early to mid week. A warming trend returns to the interior starting Monday through mid week and possibly a return to wet weather late in the work week.
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.DISCUSSION...A warming trend will set in this week as modeled 500mb patterns show a ridging pattern upstream. Clearing of coastal stratus during daytime hours will highlight fair weather for the next few days. The highest temperatures will be felt Tuesday as 850mb temperatures show the upper- level heights rise across the West Coast. This will bring a warmer temperatures and low RH early to mid week, with the driest/warmest days most likely Monday through Wednesday. Monday into Tuesday, breezy offshore winds are expected over the ridges over the eastern portion of the forecast area, particularly in the mountains of Del Norte. Interior valleys are forecast rebound to the mid to upper 90`s by Tuesday. Temperatures around 100-102 are expected at Willow Creek, Big Bar and areas along the hwy 96 between Weitchpec and Orleans. The ridge begins to weaken and move eastward by Wednesday and Thursday as a trough approaches the Pacific Northwest. Some ensemble members are showing a cutoff low forming over the coast of California, which could return monsoonal moisture to the area. The arrangement of the Pacific Northwest trough and the low over the coast of California are both uncertain, so confidence is low on any impacts. If it does end up on the wetter end (~25% of ensemble members), showers and thunderstorms are possible for the interior areas. Stay tuned. (www.weather.gov/eka/) /EYS /JB
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.AVIATION...(06zTAFs)...Model soundings are not confident in the marine layer returning tonight, yet added ambient moisture on the surface will potentially lead to radiation fog along the surface if there is no significant cloud coverage into Monday morning. IFR to LIFR conditions are most likely to form for terminals around Humboldt Bay and potentially down river valleys around Humboldt County. Inland, calm to light mostly diurnal winds are expected with WNW winds developing into the afternoon for most inland terminals and VFR conditions through the TAF period.
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.MARINE...A NW swell of 5ft@12s will dominate the waters before high pressure slowly returns beginning Monday. Strong winds and steep wind waves have called for a small craft advisory for the outer waters until Monday afternoon. These stronger pressure gradient winds will be short lived and will diminish into Tuesday. Conditions at the end of this work week are forecast to have strong northerly winds and large wind waves, but models are not confident on the extent of the wind speed as of right now. More to come.
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.EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 5 PM PDT this afternoon for PZZ470-475.
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NOTE: The full forecast discussion is now regularly issued between 10 am/pm and 1 pm/am. Additional updates will be issued as needed.
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NWS EKA Office Area Forecast Discussion