340 FXUS66 KEKA 070704 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 1204 AM PDT Mon Jul 7 2025 .SYNOPSIS...Warm temperatures expected again today in the interior, before some relief midweek. There is a slight chance for interior thunderstorms Monday. Hot weather with temperatures over 100 degrees possible Thursday into the weekend. && .DISCUSSION...High pressure continues to build in to our east while a cutoff low forms off the coast of central California. Warmer high temperatures are expected again today with 90s likely in most valleys and possibly triple digits in the Trinity River valley. The upper low off the coast moves closer over the coming days, which will trend temperatures lower. High temperatures are forecast to lower 5-10 degrees, closer to seasonal normals. Moisture associated with the upper low along with still warm temperatures in the afternoon and evening brings a slight chance for thunderstorms in the afternoon and evening. In the afternoon, the highest chances are in northern Trinity and chances slowing increasing eastward into NE Humboldt and E Del Norte into the evening and perhaps overnight. Instability looks supportive of convection, but moisture may still be limited. The upper low slowly moves northward and eastward Tuesday and Wednesday, moving most thunder potential out of the area. A stray shower isn`t out of the question Wednesday as the low moves through the area, but thunder has become less likely. High pressure builds back into the area Thursday, bringing hot temperatures back into the interior. NBM probabilities of seeing over 100 degrees is around 50%-60% Thursday for most interior valleys. Probabilities increase to over 90% by Friday with around 50% probabilities of 105 or greater. Widespread moderate to locally major HeatRisk is expected, meaning heat will be dangerous to those sensitive and without sufficient cooling. Ensembles are showing high probabilities for high pressure to remain over the area through at least early next week, with triple digit temperatures remaining possible. JB && .AVIATION...Southerly winds at the at the coastal terminals are eventually going to reverse the coastal stratus into the terminals. VFR conditions at KACV have already been reduced to MVFR as density increases and visibility decreases. Stratus is cascading from the north with a pre-existing band straddling the coastline south of Cape Mendocino. Model soundings for KACV and KCEC are showing a strong low level inversion with light wind into the early morning hours which corroborates the NBM probabilities of 40% for ceilings less than 500ft, overnight into Monday early morning hours. KUKI will be shielded from the marine layer. /EYS && .MARINE...Steep seas already being observed on buoys as they propagate into the northern inner waters. Gusts approaching 40 knots are possible as the strongest winds develop into Monday morning in Z470. Isolated gusts 15 to 25 knots are possible in far northern Z450 near Crescent City. Steep and hazardous wind waves 9 to 13 feet are forecast in response to these winds. Conditions will quickly diminish on Monday as a closed upper low cycles off the CA coast -winds may be light and southerly directly adjacent to the coast. Long range models beginning to identify another period of strong northerlies mid to late week as high pressure builds in from the SE. && .FIRE WEATHER...Warm temperatures and low afternoon humidities continue today, with slightly lower temperatures expected mid week. Overnight recoveries generally remain good aside from the exposed ridges in the thermal belt. There is a slight chance (15%) for thunderstorms this afternoon and evening in the Klamath mountains, which bring a few dry lightning strikes and gusty, erratic winds. Much hotter temperatures and drier humidity are likely in the interior late next week. Triple digit temperatures are likely in most of the interior with very low afternoon RHs and moderate overnight recoveries. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 9 AM PDT this morning for PZZ450. Gale Warning until 9 AM PDT this morning for PZZ470. Small Craft Advisory until 6 AM PDT Tuesday for PZZ475. && $$ 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