996 FXUS66 KEKA 080718 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 1218 AM PDT Sun Jun 8 2025 .SYNOPSIS...Warmer temperatures inland this weekend. A slight chance of thunderstorms over the Klamath Mountains and the Yolla Bollas on Sunday, Monday, and Tuesday afternoons. Windy afternoons return to NW California by the middle of next week. && .DISCUSSION...A strong marine layer continues to impact coastal areas of the CWA beneath a broad ridge over the PNW. Areas of dense fog are once again possible along Highway 101 from coastal Del Norte through Humboldt Bay/Eel River Valley, as well as coastal Mendocino through Sunday morning. Another warm day expected Sunday, with NBM and short-range models showing widespread interior temperatures in the upper 80`s and low to mid 90`s. Heat-prone valleys will have a greater chance of exceeding 100 degrees in the afternoon (NBM probabilities 60 to 80%), especially in areas of interior Trinity, Humboldt and Mendocino counties including Hayfork, Hoopa, Covelo, Weaverville and Willow Creek (Big Bar RAW reached 105 degrees Saturday afternoon). Those looking to cool off should exercise extreme caution if spending time in and around rivers, as waters are still cold and very dangerous. Minor HeatRisk could also impact those sensitive to heat-related illnesses. Forecast is still on track for potential convective activity as a semi-closed low aloft (700-500mb) brings an increase in mid level humidity and E-SE flow Sunday and Monday. SPC has consistently included the interior CWA in isolated thunderstorm potential through Monday evening. GFS and NAM highlight substantial moisture being ushered into Northern California - model soundings still show a very dry surface airmass beneath 5-10K feet, but above average CAPE encouraging elevated convection. Hi-res CAMs show some scenarios with convective cells developing in NE Trinity, but may stay confined further east in the central valley - NBM still reading about 10 to 20% chance for thunder in far eastern Humboldt, Del Norte and most of Trinity. Either way towering cumulus will likely begin to pop up across interior mountains in the afternoon. Monday has a slightly increased chance in Trinity county for thunder with NBM probabilities 20 to 25%. Mid-level moisture availability and consistently warm temperatures contribute to potential instability. Potential for gusty winds and dry lightning could be a fire weather concern for these areas. Chances for storms decrease on Tuesday with less available mid level moisture - convective development looks to stay much further east of CWA in southern OR and NE CA, potentially reaching the Trinity horn. Brief ridging on Tue may be followed by a deeper trough Wed and Thu next week. This trough looks quite dry and main impacts appear to be a return of stronger gusty winds and cooler temperatures. && .AVIATION...Confidence for LIFR stratus at coastal terminals is high, with a 100% chance of ceilings less than 500 ft at KCEC and 80% chance of the same at KACV overnight and early Sunday morning. However at KUKI there is a near 0% chance of LIFR stratus, largely from the chance of wind direction back to the north along with a shallow marine layer. Chances of visibility less than a mile of at least 50% exist for both coastal sites as well, with NBM deterministic forecasts at 1/4 SM at both sites for overnight and early Sunday morning. Stratus will be quite stubborn along the coast for Sunday. The potential of ceilings below 1000 ft at KCEC does not drop below 60% for Sunday afternoon and doesn`t drop below 50% for KACV. Potential for at least a short return to VFR visibility Sunday afternoon is 60% for KCEC and 80% at KACV. Confidence is high that KUKI remains VFR, with median northwest gusts at 14 KTS for Sunday afternoon. /MH && .MARINE...For overnight into Sunday, north light winds and lower seas are forecast to keep impacts low, though stratus will create foggy conditions in the overnight into Sunday morning. Northerly winds gradually pick up again next week, with north winds forecast 20-25 kts by Tuesday. The potential for gales (40-60% chance) arrives by Wednesday and Thursday. Combined wave forecast matches up with NBM 90th percentile forecast fairly well as combined heights of 10 feet introduced into the northern waters by 06Z Tuesday and becoming more predominant among all waters by Wednesday night into Thursday. /MH && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... None. && $$ NOTE: The full forecast discussion is now regularly issued between 10 am/pm and 1 pm/am. Additional updates will be issued as needed. 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