Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
052 FXUS66 KEKA 112154 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 254 PM PDT Tue Jun 11 2024 .SYNOPSIS...Cloudy stratus will begin to collect on the coast. Hot and dry conditions continue through mid week for most of the interior. Strong northerly winds will continue through tomorrow for exposed coastal mountains and headlands. Temperatures are forecast to trend down during the latter portion of the week, followed by more substantial cooling over the weekend as gusty northwesterly winds strengthen in the interior. && .DISCUSSION...A weak cold front along with a steeper pressure gradient, will bring gusty northerlies to bare on coastal regions this afternoon through the evening. Not much in the way of precipitable water as 700mb models show moisture dissipating before reaching land and skew-T sounding`s Pwat values diminishing below 0.6 at the coast. Despite a lack of precipitation it looks like conditions for stratus development have been primed for the northwest facing areas which are already showing buildup from Capetown to Klamath. A shallow inversion could pack this stratus into the hwy 101 corridor as the evening approaches, as the HREF ensemble mean and soundings suggests. Dry conditions will continue through to the end of the week and into the weekend. Of particular interest is the Heat Advisory for Southern Lake county with temperatures from the upper 90s to low 100s. Southern Lake including Hidden Valley Lake, Middletown, Clearlake Park, Finley, Clearlake, Knobcone Camp, and Lakeport will be under a Heat Advisory until 8pm PDT tonight. Please be cautious to reduce risk during outside work and schedule frequent breaks. Those without effective cooling and/or adequate hydration will be at the greatest risk. Low to moderate heat risks are expected elsewhere in the interior. Interior Humboldt and Del Norte counties are projected to peak in the mid 80s to around 90F today. Temperatures are forecasted to be similar on Wednesday. An upper level Low persists off the coast of British Columbia, and will provide an upstream trough with zonal westerly flow aloft, which will edge toward the West Coast Thursday through Friday. National Blend of Models (NBM) remains consistent with temperatures trending down, but still above mid June normals, especially on Thursday. NBM indicates more substantial cooling over the weekend as another 500mb trough dips down from the NW. This trough is forecast to be relatively dry and right now the potential for any precipitation is quite meager, 5-10% chance for mostly Del Norte by late in the weekend. The trough will most likely result in deeper mixing and much stronger westerly to northwesterly winds across the interior. There is even a chance (30-50%) for morning frost in the colder valleys of Trinity and eastern Humboldt counties by Sunday. Also. rain possibilities increase early to mid next week (June 17-19), though still quite meager with NBM probabilities for 0.10in or more in 24 hours no more than 20% for mostly Del Norte and northern Humboldt counties. && .MARINE...A brief reprieve in winds overnight generated a disorganized sea state largely influenced by a mid-period NW swell. Gusty northerlies are rapidly increasing as expansion fans develop downwind of southern OR and Cape Mendocino. Gales expected to enhance already elevated conditions in the southern waters early this evening before migrating to the northern outer waters overnight. Responsive seas approaching 12-15 feet are likely early Wednesday into Thursday across all zones as gale gusts approaching 40 knots drive steep northerly wind waves. Advisory level winds and elevated seas expected to continue through the end of this week as a series of long period westerly swells fill into the waters. && .AVIATION...Despite strong northerly winds on coastal headlands, a weak frontal boundary traversing the north coast will briefly push stratus into the coastal terminals. Scattered ceilings will still allow intermittent clearing and mostly VFR conditions as winds slowly diminish through early evening. Northerly gusts up to 20 mph anticipated at UKI late this afternoon before diminishing beneath clear skies. Overcast IFR stratus expected to return to ACV overnight, although light offshore winds will likely prevent significant reductions in visibility`s. HREF indicates stratus hanging on a bit longer than this morning south of Trinidad, once again scattering out with increasing north winds. Lower probabilities for a southerly wind reversal pushing stratus to CEC before winds redevelop Wednesday afternoon. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... Heat Advisory until 8 PM PDT this evening for CAZ115. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 9 AM PDT Thursday for PZZ450. Small Craft Advisory until 3 PM PDT this afternoon for PZZ455. Gale Warning until 9 PM PDT Wednesday for PZZ455. Small Craft Advisory until 9 PM PDT this evening for PZZ470. Gale Warning from 9 PM this evening to 9 AM PDT Thursday for PZZ470. Gale Warning until 9 AM PDT Thursday 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