Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
273 FXUS66 KEKA 222204 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 304 PM PDT Sun Sep 22 2024 .SYNOPSIS...Warm and dry conditions will continue to gradually settle in today with weakening north winds along the coast. Heat will peak early this week with above average temperatures pushing out even along the coast. && .DISCUSSION...High pressure continues promoting dry and warm pattern across Northern California through Tuesday. Mostly clear skies prevail across the area, except along the Mendocino Coast where a shallow marine layer persist. Breezy north-northwesterly winds will occur along nearshore and along Eel River Valley into early evening. Overnight temperatures are expected to cool into low 50`s, while a strong thermal belts will maintained upper elevation lows in the 60s. The low-level airmass will continue to warm on Monday (850mb temperatures ranging from 23 to 26), with high temperatures between 100 to 105F in the hottest interior valleys. The ridge will begin to slowly shift eastward on Tuesday, however similar temperatures. These temperatures will be 10 to 15 degrees above normal, promoting Moderate Heat Risk Monday and Tuesday across the interior. This level of heat affects most individuals sensitive to heat, especially those without effective cooling and/or adequate hydration.This level of heat affects most individuals sensitive to heat, especially those without effective cooling and/or adequate hydration. Even the coastal areas are anticipated to warm up above normal with high in the 70`s as northerly winds weaken, especially along the North Coast. Confidence is not high for the Mendocino Coast due to the persistent shallow marine layer. High pressure will begin to breakdown and slowly shift eastward on Tuesday as an upper level trough approaches the Pacific Northwest. Meanwhile, a cutoff located offshore southern California will drift northward parallel to the coast before being absorbed by the upstream trough late Tuesday night. The main trough will move across the Pacific Northwest on Wednesday, followed by another trough around Thursday. Overall for our area not much chances of precipitation is expected, other than some light drizzle along the coast. The primary affect from these transient shortwave troughs will be to knock temperatures down to around seasonal or slightly below seasonal averages; highs from upper 88 to 91F. /ZVS && .AVIATION...Clear skies are forecast to continue at all terminals through this TAF period. Stratus and fog will continue to result in LIFR cigs and vsbys along the Mendocino coast tonight through Monday. Only patchy stratus and fog is expected around Humboldt Bay/Eel Delta with less than a 20% chance for LIFR at KACV from 14Z to 18Z Monday. Very marginal low level wind shear remains possible at coastal terminals after surface winds decouple and east winds to 25kt develop a thousand feet above mean sea level this evening. DB && .MARINE...Near gale conditions with occasional gusts to around 35 kt and large steep northerly wind waves near 10 feet are forecast to continue in the outer waters through Monday. Steep wind waves will also propagate into the inner waters through Monday, primarily in the northern inners. Northerly conditions will ease Monday night and then lay down more substantially on Tuesday and Wednesday as the thermal trough weakens and shifts inland. A series of mid period NW swell will build early next week, peaking around to around 8 ft on Wed. Potential for gale force northerlies and large steep waves over 10 feet will increase Fri-Sat. DB && .FIRE WEATHER...(From previous discussion) Building heat and high pressure this week will continue to enhance fire weather conditions with daytime highs in the mid 90s to low 100s and minimum RH in the teens. Overnight recoveries will continue to be poor at mid and high elevations with recoveries of 20 to 40 percent though Tuesday morning. Except for some enhanced north wind right along shore and channeled along the Eel river valley Sunday, daytime winds will be mostly gentle and terrain driven. Low pressure off the central California coast combined with high pressure will help enhance night time northeast flow at high elevations. Northeast wind gusting up to 25 mph should be expected a high elevations late each night early this week. This risk will be focused in the usual areas of Del Norte and Lake Counties but will also include the usually calmer ridges of Southern Humboldt and northern Mendocino Counties. Generally more mild conditions will build in late in the week with increasing marine influence. /JHW && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 9 AM PDT Monday for PZZ450-455. Small Craft Advisory until 9 AM PDT Tuesday 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