Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
107 FXUS66 KEKA 152228 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 328 PM PDT Sat Jun 15 2024 .SYNOPSIS...Dry weather is expected to continue through the foreseeable future. Interior temperatures continue to drop below seasonal normals into early next week. Breezy to windy westerly to northwesterly winds this afternoon and evening, with much stronger winds are expected this Sunday evening into Monday. && .DISCUSSION...A broad upper-level trough centered over the Vancouver Island and Pacific NW will aid in continuing a cooling trend through early next week. Latest WV satellite imagery show high-level clouds spreading across much of the northern portion of the forecast area this afternoon, while some pocket of cumulus clouds are present over the higher terrain in Humboldt and Del Norte counties. As expected, high temperatures are running up to near 10 degrees cooler today compared with Friday`s reading, with at or near seasonably temperatures. Breezy west northwest are expected to continue this afternoon over the coastal headlands and exposed ridges, but a bit weaker than Friday evening. Cold air will continue to flow over Northern California Sunday through early next week as a embedded shortwave trough within the upper-level trough swing east-southeast. The primary concern with this feature looks to be wind, and gusts from 25 to around 35 mph are likely across Lake and southern Mendocino counties, and latest NBM ensemble guidance is indicating a chance (20 to 30%) of gusts exceeding 40 mph at Cow Mtn and near Cobb in Lake County. With afternoon RH values forecast to reach the low 20 to teens each afternoon this weekend, there exists a slight risk for rapid spread of grass fires on Sunday. 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. There is a chance (20 to 40%) for brief morning frost in the colder valleys of Trinity and eastern Humboldt counties Sunday night. Precip chances have dried up with recent guidance, with general consensus that approaching moisture with this shortwave will split offshore on Sunday and miss NWRN CA to the north and south...with less than a 5% chance of one hundredth of an inch in Del Norte and Humboldt counties. Afternoon high temperatures are forecast to slowly trend back toward climatological normals next week, with longwave troughing continuing aloft well into the work week. && .AVIATION...Gusty northerly winds originally scattered and cleared out cloud cover this morning with some exception for cirrus groups streaking by at higher altitudes, flight conditions will prevail in VFR categories through the TAF period. LLWS, low level wind shear will pose a threat at most terminals this afternoon through evening with velocity and directional differences. Northerlies begin to back off by 6z at KCEC and KACV. KUKI will also have challenging LLWS at times with intermittent gusty northerlies lasting through the evening but will begin to ease by 5 or 6z as well. /EYS && .MARINE...Gales are in effect for the southern inner and outer waters through Sunday, with the southern inner zones PZZ455 lasting a bit longer into the evening on Sunday. Steep square waves return Sunday morning for the northern waters, bringing 6 to 8ft wave heights at 6 to 8 seconds...which will last through to Monday and possibly Tuesday for the northern outer waters, PZZ470. Gale conditions will persist in the lee of Cape Mendocino as the northerlies accelerate around the Cape, to the south. /EYS && .FIRE WEATHER...Breezy west to northwest winds continues this afternoon and evening, especially through the channeled terrain and exposed ridges. Moderate to good RH recoveries was observed this morning with generally 50 to 70% on the ridges and interior valleys, mostly in the eastern portion of Mendocino, Trinity and Lake counties. Daytime RH values are expected to continue lowering with values from 15 to 25% range this afternoon. This very dry conditions is expected to continue over the eastern portions of the forecast area with RH values in the 20`s and teens. Winds are expected to become breeze to windy on Sunday, with gusts up to around 35 mph. A chance (20 to 30%) for gusts to reach above 40 mph at Cow Mtn and Cobb in Lake County, but mixing down into some spots around Clearlake Sunday evening. Winds shift to north-northeast Sunday overnight. These is expected to bring drier air and continue with critical conidtions in fire weather zone 264. These winds are expected to diminish into Monday morning. However, the daytime humidity are forecasted to be in teens. A Red Flag Warning remains in zone 264 (southern Lake), from late tonight through Monday evening, primarily for the possibility of rapid spreading grass fires. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... Red Flag Warning from 11 PM this evening to 8 PM PDT Monday for CAZ264. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 3 AM to 9 PM PDT Sunday for PZZ450. Small Craft Advisory until 3 PM PDT this afternoon for PZZ455-475. Gale Warning until 9 PM PDT Sunday for PZZ455. Small Craft Advisory from 3 AM Sunday to 9 PM PDT Monday for PZZ470. Gale Warning until 3 PM PDT Sunday 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