Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
201 FXUS66 KEKA 181935 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 1235 PM PDT Mon Aug 18 2025 .SYNOPSIS...A gradual warming and drying trend will continue and intensifies late this week. Inland temperatures warming to above 100 late this week and through the weekend will create fire weather concerns and a Moderate to locally Major HeatRisk. && .DISCUSSION...Low clouds and a patchy shallow fog layer have mostly dissolved for this afternoon, allowing for warmer coastal temperatures. The marine stratus is modeled to redevelop and invade the coast again fairly quickly this evening. There remains shallow moisture near the surface, and this will allow for some overnight/early morning patchy fog to redevelop. A shortwave perturbation will clip the northern region Wednesday, but is expected to have little impacts other than suppressing the greater inevitable warmup. Beyond the passing of the shortwave, temperatures will indeed further warm late in the week with a strengthening Four Corners Region High. 500 mb heights are forecast to reach 594 to possibly up to 597 dm Friday. This setup has strong reliability and high forecast confidence for hot temperatures through our region. The probability for isolated warmer valleys to exceed 100 increases Thursday. Chances for temperatures over 100 are highest Friday (90%) for the interior valleys. The hot daytime temperatures and warm overnight lows will bring Moderate to some areas of Major HeatRisk late this week and into the weekend. Chances for high tempertures over 100 begin slowly dropping for some Saturday, but they will be similar to Friday for most. Troughing will deepen from the north by Sunday. This will begin weakening the Four Corners high and start slowly trending temperatures back down. The Four Corners region high will tap into monsoonal moisture at the end of the week. Models clip our area with some of this moisture late Friday and through the weekend. Currently, the moisture quality and instability look too low to raise thunderstorm chances, but this will have to be watched closely for fire weather concerns with the dry surface conditions and likeliness of little to no precipitation from anything that forms. /JJW && .AVIATION...This afternoon there are some small patches of stratus along the coast. Most notably one is covering KCEC. This may still pull back from the coast this afternoon, but it may be brief. Tonight widespread low clouds are expected to bring LIFR conditions again. These are not expected to make it as far inland as they were this morning. Confidence is also low on the timing of their return, but there is stratus just off the coast so it will likely return quickly. Tuesday the inversion is expected to be weak again which should help to allow clouds to clear reasonably quickly in the morning. MKK && .MARINE...Winds remain light to locally moderate this afternoon. The strongest winds are expected in the lee of Cape Mendocino. Waves are dominated by a 4 to 5 foot wave at 11 seconds. The stronger winds south of Cape Mendocino may generate some 1 to 2 foot wind driven waves. These winds are expected to remain light tonight and into TUesday morning. Tuesday afternoon the winds in the lee of Cape MEndocino are expected to increase to around 15 to 20 with generally lighter winds elsewhere. These localized winds will once again bring some steep northerly waves around 2 feet. The 10 second wave is expected to continue around 4 to 5 feet. Late Tuesday night and Wednesday northerly winds are expected to increase again. Currently they are expected to be around 10 to 20 in most areas with gusts to 35 kt in the lee of Cape Mendocino. Small craft advisories will likely be needed in at least some of the zones. These stronger winds are expected to increase through at least Saturday before they may start diminishing. The seas are expected to be dominated by short period wind driven waves building to around 8 feet on Friday. Starting Thursday the models are showing there may also be a small south to southwest long period wave. MKK && .FIRE WEATHER...A warming and drying trend has begun for the area as high pressure strengthens from the Four Corners region. Winds will be diurnally driven with westerly afternoon breezes that will be gusty at times. The Minimum RH will drop to the low teens to single digits starting Thursday as the heat intensifies and overnight offshore winds strengthen. The hot and dry conditions with some poor overnight recoveries will carry through the weekend. The Four Corners region high will tap into monsoonal moisture at the end of the week. Models clip our area with some of this moisture late Friday and through the weekend. Currently, the moisture quality and instability look too low to raise thunderstorm chances, but this will have to be watched closely with the dry surface conditions and likeliness of little to no precipitation from anything that forms. && .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