FXUS66 KEKA 162213 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 313 PM PDT Sun Jun 16 2024 .SYNOPSIS...Critical fire weather conditions for southern Lake County this afternoon through Monday evening. Breezy to windy west to northwest this afternoon and evening, with strongest winds late afternoon and evening. Dry weather is expected to continue through the foreseeable future. Interior temperatures continue to drop below seasonal normals into early next week. A gradual warming up from Tuesday, with another heat possible late in the week. && .DISCUSSION...A broad upper-level trough centered over British Columbia and northern Washington will continue to swing another shortwave across Northern California this afternoon and evening. This feature is bringing mid to high level moisture across much of the area. Otherwise, dry weather is expected to continue with some cooling of interior high temperatures. Breezy west to northwest winds are already observed this afternoon. Winds are forecast to strengthen late this afternoon and evening. Gusts from 25 to around 35 mph are likely this afternoon, especially in southern Lake ans Mendocino counties. HREF and NBM continue suggesting gusts at 40 mph or greater at Cow Mt and east and south of Cobb in Lake County. With afternoon RH values forecast to reach the low 20 to teens this afternoon, there exists a slight risk for rapid spread of grass fires today in Lake county. See Fire Wx section for more details. Otherwise, slightly cooler air and continued dry conditions with clear skies should result in chilly overnight temperatures once winds decouple, especially for the northern portion of the forecast area. This will promote temperatures dropping to low 40s to mid 30s across the interior early Monday morning. A brief morning frost is expected in the colder valleys of southern Trinity and eastern Humboldt counties as this shortwave progresses east of the area, with building high pressure over the great basin. This will promote light, drying NE winds early Monday morning across much of the interior. A Frost Advisory is now in effect from 8PM tonight through 9AM Monday in response for those areas. Afternoon high temperatures are forecast to slowly trend back toward climatological normals next week, with longwave troughing continuing aloft well into the work week. Afternoon highs may creep back up to above normal late this week as ridging noses in from the west. && .AVIATION...All terminals are VFR this afternoon, with gusty northwest winds being reported at both ACV and UKI. CEC may also see this evening. Winds will ease after sunset at all the terminals. VFR conditions are expected to remain at the terminals overnight, with the only uncertain terminal being ACV, where there is some potential for low clouds overnight anchored around Humboldt Bay and the surrounding mountains. These could bring some brief MVFR ceilings to ACV before sunrise. VFR conditions are once again expected Monday after sunrise, with breezy northerly winds returning to all the terminals in the afternoon. JB && .MARINE...Northerly winds have come in a bit lower than previous model runs suggested today, though winds remain breezy. Peak gusts of around 25 to 30 knots in the expansion fan south of Cape Mendocino along with steep wind waves of 7 feet at 7 seconds are expected for the rest of the day. Outside the expansion fan, the sea state is dominated by a northwesterly swell filling in at around 4 feet at 9 seconds. Both winds and waves will increase Monday afternoon, with gale force gusts up to 40 knots forecast in the expansion fan south of Cape Mendocino. Winds are forecast to ease below gales after sunset Monday. JB && .FIRE WEATHER...Breezy to windy west to northwest winds are expected to develop today, with gusts of 25 to 35 mph expected across Lake, Trinity, and southern Mendocino counties, and a chance (20 to 30%) for gusts to reach above 40 mph at Cow Mtn and around Cobb in Lake County. In addition, Dry conditions with low daytime RH's in the 20's and teens are expected to continue this afternoon. Winds are forecast to weaken late tonight and turn NE, ushering in a drier airmass and possibly driving RH values into the low teens on Monday. The strong winds and low humidity will yield an elevated fire weather threat through Monday evening, particularly for the south and east side of Lake County. A Red Flag Warning remains in zone 264 (southern Lake), from today through Monday evening, primarily for the possibility of rapid spreading grass fires. Tuesday will be another dry day with daytime RH's in the teens, with moderate to locally poor humidity recoveries. However, winds are expected to be light up to 12 mph sustained. Elevated fire weather threat will most likely on Tuesday due to the low daytime humidity. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... Frost Advisory from 3 AM to 9 AM PDT Monday for CAZ106-108. Red Flag Warning until 8 PM PDT Monday for CAZ264. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 9 AM to 9 PM PDT Monday for PZZ450. Small Craft Advisory until 9 PM PDT Monday for PZZ455-470. Small Craft Advisory until 9 AM PDT Monday for PZZ475. Gale Warning from 9 AM to 9 PM PDT Monday 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