Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
989 FXUS66 KEKA 162303 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 403 PM PDT Mon Sep 16 2024 .SYNOPSIS...Interior showers this afternoon and evening. Another round of rain showers is expected Tuesday through Wednesday with the heavier showers in the north. A drying and warming trend is expected late in the week. && .DISCUSSION...A closed low spinning over the Sierra Nevada in Northern California this afternoon is bringing increasing mid to high level moisture from northeast across the area. Radar reflectivity depict light returns across the eastern portion of Trinity County this afternoon. Chance of wetting rain still possible across portions of northeastern Mendocino and northern Lake county late this afternoon. Showers are expected to tapper off this evening as the upper trough continues to shift eastward. Breezy northwesterly winds are observed this afternoon, with gusts up to 35 mph over the coastal headlands in Humboldt and Del Norte counties. Winds are expected to diminish later this evening. Tonight, a brief period of weak ridging is expected between the upper lows. Some coastal drizzles are expected around Humboldt Bay and vicinity late this evening and overnight with a deep saturated layer. Temperatures will be chilly, but even the coldest valleys are only expected to drop into the upper 30s. The next upper level is forecast to move down from the north just off the West Coast Tuesday afternoon and overnight. As that occurs, this will continue to become in a negatively tilted trough while evolve into a closed low just near the NW California Coast. Rain are expected to start to move from NW across the northern portion of the area Tuesday afternoon. Additional rainfall will develop and stream across the area from NW toward Mendocino and Lake counties Tuesday night into Wednesday morning as the cyclone potentially brushes the forecast area before temporarily stalling out. Rainfall total amounts are forecast to range from over 0.5" in the mountains of Del Norte County to near tenth of an inch for southern Mendocino and Lake County. Rainfall total amounts range from 0.30 to 0.50 of an inch for Del Norte and northern Humboldt, with the heaviest rainfall over the mountains of Del Norte County. Lighter amounts from few hundredths to a quarter of an inch are expected for areas farther south and east, including southern Humboldt, Trinity, Mendocino and Lake counties. Showers will gradually taper off Wednesday morning from north to south with lingering showers through Wednesday afternoon as the low continue moving toward southern California. Ensemble clusters show ridging building in from the west late this week, possibly bringing dry weather from late this week into the weekend. Temperatures are expected to warm up, but will remain mainly seasonably. /ZVS && .AVIATION...A variety of clouds, (mostly middle clouds) rotated across the region from a low that moved southward today. Conditions were VFR except for brief late morning "low" MVFR and IFR Cig/Vis from Humboldt Bay to ACV. Widely scattered cumulus continued over large portions of the flying areas through afternoon: these had the potential for an isolated shower over the eastern mountains. A sustained tight pressure gradient along the the far North Coast, produced breezy-gusty coastal winds at CEC. Surface winds will greatly diminish late tonight, which according to most model guidance, will allow for stratus clouds to impact the ACV and CEC Taf sites. /TA && .MARINE...Hazardous conditions for small craft across the coastal waters are expected into Tuesday morning. Northerly winds and seas will continue to gradually diminish and subside through Tuesday. Winds are expected to become light to gentle from west to northwest Tuesday morning as a frontal system approaches. Unsettled weather condition is expected Tuesday afternoon through Wednesday afternoon. Isolated thunderstorm activity and erratic gusty winds are possible Tuesday evening through Wednesday morning.Northerly winds are expected to return on Wednesday morning, and increase into Thursday, especially across the outer waters. Gust up to around 30 kts are forecast from Wednesday into Friday. These winds will promote steep seas around 7-9 feet Thursday through Friday. /ZVS && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 9 AM PDT Tuesday for PZZ450-455. Hazardous Seas Warning until 3 PM PDT this afternoon for PZZ470-475. Small Craft Advisory until 9 AM PDT Tuesday for PZZ470-475. && $$ 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