Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
231 FXUS66 KEKA 282153 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 253 PM PDT Fri Jun 28 2024 .SYNOPSIS...Coastal stratus and patchy drizzle will scour out with increasing NW winds. Slightly elevated daytime RHs expected as a shortwave moves through the region on Saturday, enhancing marine influence up river valleys. A warming and drying trend is expected to intensify early next week - fire weather and heat risk have potential to become increasingly critical heading into the July 4th holiday. && .DISCUSSION...The coastal pressure gradient will continue to enhance diurnally driven NW winds this afternoon as Pacific high pressure builds toward the interior thermal trough. Many interior valleys are currently in the high 80s to low 90 degrees already, and temps are expected to continue to climb for the next hour or two. With increasing temperatures, min daytime RH values have dropped into the mid teens and low 20`s in valleys of Lake, interior Mendocino, and Trinity counties. Interior wind gusts are not expected to exceed 15- 20 mph, but a brief slight fire weather risk still exists. A weak upper shortwave is expected to disrupt the marine layer and bring some mid-level moisture to the area along a weak frontal boundary Saturday morning. NW winds 5-15 mph are forecast across the interior through late Saturday night, with gusts reaching 20-30 mph on exposed ridges. Surface RH`s will be slightly elevated as this trough sustains marine influence for coastal counties through the weekend, with interior valleys not expected to drop below 20 to 25 percent min daytime RHs. Even so, these gusty winds will pose potential for fire weather risk. Long-range models are becoming increasingly confident in anomalously warm ridging building into the eastern Pacific beginning late Monday, coupled with potential for widespread min RHs in the teens and single digits by mid-week amidst NE flow. Interior temperatures have a fairly high probability of reaching the upper 90`s and low 100s with coastal temperatures in the 60`s and low 70`s from Tuesday through late next week. Stay tuned for continuous updates on potential for significant HeatRisk and heightened fire weather conditions. && .AVIATION...A narrow swath of marine stratus lingered along the coastline from Cape Mendocino to the Del Norte/Oregon border. A pilot report (pirep) out of ACV this morning measured tops at 1400 feet which matched with profiler heights. LIFR/IFR conditions prevailed through noonday in Del Norte and middle afternoon at ACV. At the Taf sites, afternoon/evening gusty coastal winds will be a repeat of yesterday. However, stronger gusts are expected at CEC. Inland areas have and will continue to be VFR through Saturday. Most model guidances and the local Bufkit are showing a return of the coastal stratus by late evening. /TA && .MARINE...Northerly winds will continue strengthening today, with local gale force gusts likely south of Cape Mendocino. Short period seas will pick up to around 8 to 10 feet at 8 to 9 seconds late afternoon and evening as result. Tomorrow, a weak cold front will move into our area disrupting the thermal trof. This short-wave disturbance will force winds in the northern waters to weaken slightly, tomorrow afternoon until next week. Monday, winds are forecast to strengthen again as a high pressure offshore begin to builds in quickly in the wake of the trough. A thermal trough is then expected to develop near the coast Monday night/early Tuesday creating a moderate to strong pressure gradient along the coast. Widespread strong to near gale force winds in the outer waters and very steep, hazardous seas (14-15ft @ 10s) are forecasted for early-mid next week. && .FIRE WEATHER...Gusty W winds combined with 15-25% minimum daytime RH values may pose a brief increased fire weather threat this afternoon and evening, especially in Lake and eastern Trinity counties. Greatest threat to fine fuels in areas below 2000 feet. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 11 PM PDT Sunday for PZZ455-475. Small Craft Advisory until 9 AM PDT Sunday for PZZ470. && $$ 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