Area Forecast Discussion
Issued by NWS Eureka, CA
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Issued by NWS Eureka, CA
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-- Discussion containing changed information from previous version are highlighted. --244 FXUS66 KEKA 032157 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 257 PM PDT Fri May 3 2024 .SYNOPSIS...-- Changed Discussion --A cold front will move across the area this evening through early Saturday morning bringing a period of heavy rain. Brief heavy wet snow is also expected above 2500 feet early Saturday morning. Colder air will settle over the area for Sunday and persist through the middle of next week bringing near freezing and freezing temperatures expected for the interior valleys during early morning hours.-- End Changed Discussion --&& .DISCUSSION...-- Changed Discussion --Satellite shows the unseasonably strong cold front off the coast this afternoon. Rain is expected to start in Crescent City between 3 and 4 pm and move south with it expected to make it to Eureka around 7 pm or so. Moderate to heavy rain is expected with this front with widespread 1 to 3 inches across the area. The mounts of Humboldt and Del Norte counties show up to 4 inches while the valleys of southern Lake and eastern Trinity counties may only see around a half inch. Snow levels are expected to fall rapidly as this front moves in and are expected to be around 2,500 to 3,500 feet by Saturday morning. The lowest levels are expected to be in Humboldt and Del Norte counties. This will likely bring several inches of snow above the snow level. With the warm ground temperatures and high sun angle this is expected to melt fairly quickly on Saturday. The winter weather advisory remains on track. Saturday afternoon showers and possibly thunderstorms are expected. There is a lot of cold air aloft with 500 mb temperatures dropping to -32. This has the potential for some instability to develop if skies clear, but this is uncertain. There is still around a 15 percent chance for thunder. Saturday night the precip comes to an end and it has the potential to be a cold night. The temperatures at 850MB are only around -3C. This could bring freezing temperatures as low as 2,000 feet even if skies remain cloudy and there isn`t any radiational cooling. Any valleys that do clear out could see temperatures drop below freezing. Sunday afternoon temperatures will remain well below seasonal normals with highs likely remaining in the 50s in the most areas. A freeze watch may be needed in Trinity, but there is currently a winter weather advisory in place in many of the areas that will potentially see freezing temperatures so have held off. Sunday night and Monday a short wave and associated cold front is expected to bring more light rain and additional clouds, especially in the north. Rainfall amounts have increased with this system in Del Norte county amounts are now close to a half inch. This will likely leave lingering moisture that develops into low clouds or fog in the north. This is expected to keep the northern the northern areas from getting as cold, although Mendocino and Lake counties could see freezing temperatures. Tuesday and Wednesday will likely see more clearing skies allow more radiational cooling, however warm advection will be warming temperatures aloft each day. Frost or freezing temperatures are possible both nights, although there is still uncertainty on the locations. Thursday and Friday the models show high pressure building back into the area with Ukiah, Lakeport, and surrounding areas getting back into the 80s. Friday Lakeport has a 35 percent chance of exceeding 85 degrees. MKK-- End Changed Discussion --&& .AVIATION...-- Changed Discussion --A brief period of IFR level stratus moved over ACV this morning. Otherwise, prevailing cloud/visibilities into mid- afternoon have been VFR low-mid Cigs. Prefrontal conditions are forecasted to slowly dip down to MVFR, then IFR this evening. The cold front will arrive this evening preceded and accompanied by periods of moderate to heavy rain...which will definitely impact ACV and CEC`s flight operations. Just ahead of the front, there is a minimal threat of LLWS at CEC, but the main concern will be increased surface wind gusts this evening along the coast. Rain should taper Saturday morning and become more shower; Cig/Vis will be on the rise also. Note: Flight hazard: snow could impact air operations across the interior higher terrain. /TAA-- End Changed Discussion --&& .MARINE...-- Changed Discussion --Winds will continue to become southerly and increase ahead of an approaching frontal passage. Gusts 15-20KT will develop first in the northern waters along the frontal boundary late this evening into early Saturday morning, quickly turning W/NW behind the front. Gusty NW winds will become confined to the southern waters amidst scattered convective showers Saturday evening. Steep wind wave response expected late Saturday through Sunday as lingering showers dissipate. Combined seas are forecast to be 6-7 feet with 7-9 second periods through the weekend before a long period NW swell fills in early next week. Strong northerlies combined with another steep NW swell mid week may produce combined seas exceeding 10 feet.-- End Changed Discussion --&& .EKA WATCHES/WARNINGS/ADVISORIES...-- Changed Discussion --CA... Winter Weather Advisory from 4 AM to 11 AM PDT Saturday for CAZ102-105>108-111. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 9 PM this evening to 3 AM PDT Saturday for PZZ450. Small Craft Advisory from 9 PM this evening to 9 AM PDT Saturday for PZZ470. Small Craft Advisory from 3 AM to 9 PM PDT Saturday for PZZ475.-- End Changed Discussion --&& $$ 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