775 FXUS66 KEKA 072112 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 212 PM PDT Mon Jul 7 2025 .SYNOPSIS...Slightly cooler temperatures are expected Tuesday and Wednesday. Warming is expected again Thursday with additional warming Friday with the heat continuing into the weekend. && .DISCUSSION...An area of low pressure is approaching from the west this afternoon. This has brought a southerly surge of stratus and southerly winds along the coast. This is also bringing some cooler air aloft and generating some instability. This may allow a few thunderstorms to develop this afternoon and evening. The majority of the activity is expected to be in Siskiyou county. However a few of them could develop in northern Trinity county mainly over the higher terrain. With a westerly storm motion these may push into Del Norte county this evening, but confidence is low on this. Tonight and Tuesday a deeper marine layer is and more widespread stratus is expected as the upper level low continues to approach the area. This is expected to bring some cooler temperatures, especially in the near coastal areas. This is expected to continue into Wednesday. This has the potential to bring a thunderstorm or two, 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. MKK/JB && .AVIATION...Persistent southerlies are driving marine stratus up the north coast, bringing IFR to LIFR ceilings to the coastal terminals. A brief period of scattering is possible this afternoon as cloud cover retreats to the immediate coastline, but will be shortlived if verified. Gusts 15 to 20 knots possible at CEC this afternoon and lee of other coastal headlands. UKI will experience similarly gusty conditions this afternoon. IFR stratus expected to return after 03Z this evening as southerly flow continues to drive the cloud deck into the coast. Model soundings indicate a strong inversion keeping ceilings <1000 feet with reduced visibilities likely overnight (HREF 50 chance <1 sm through 15Z). With strong southerly flow, there is also a chance of stratus reaching UKI up the Russian river valley around sunrise (around 20%). && .MARINE...Steep wind waves are still being observed in the inner waters this afternoon as northerly winds gradually migrate further offshore. Gentle to moderate southerly breezes will continue in areas adjacent to the coast, especially lee of coastal headlands. Conditions will continue to diminish this afternoon and overnight as a closed upper low cycles off the CA coast. Winds and seas will remain especially calm Tuesday through late Wednesday as a small southerly swell fills into the waters. Another period of strong northerlies is likely mid to late week as high pressure builds in from the SE. NBM and mid range model guidance shows 50 to 60% chance of gale gusts developing in the outer waters beginning early Thursday. && .FIRE WEATHER...Warm temperatures and low afternoon humidities continue today, with slightly lower temperatures expected Tuesday and Wednesday. 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. These are mainly expected to be in Siskiyou county, but there may also be some in northern Trinity county. A few may also drift west into Del Norte county this evening. Any that do form are expected to bring a few dry lightning strikes and gusty, erratic winds. Much hotter temperatures and drier humidity are likely in the interior late this week. Triple digit temperatures are likely in most of the interior valleys by Friday with very low afternoon RHs and moderate overnight recoveries. MKK && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 5 PM PDT this afternoon for PZZ450. Small Craft Advisory until 8 AM PDT Tuesday for PZZ470-475. && $$ 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