FXUS66 KEKA 082142 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 242 PM PDT Sun Sep 8 2024 .SYNOPSIS...Stratus has thinned out and retreated from the coast this afternoon, delivering pleasant weather which will continue to be mild for the next few days. A low pressure system is expected mid- week, potentially bringing gusty winds and light rain. && .DISCUSSION...Dry and warm conditions continue for the next few days ahead of an upper level trough, expected to arrive Wednesday. Until then, mild conditions near the climatological norms will be the trend. Low RH values for the interior areas will persist through Tuesday, although criteria for fire danger will not be fully developed until winds increase with the incoming pressure gradient mid-week. By then, the moisture flux will increase RH values and overnight recoveries which will isolate fire weather threats to areas that are less likely to receive wetting rain and maintain low RH values. Lake and interior Mendocino counties may have a window of high risk/fire danger as gusty winds arrive Tuesday with very low probabilities of wetting rain being signaled by models at this time for the southern half of the CWA. NBM shows probabilities of wetting rain (>0.1 in) at around 65-70% in Del Norte County, around 40-50% in Humboldt and Trinity Counties, and 10-20% in Mendocino and Lake Counties. Gusty northwest wind is being signaled Tuesday evening, with NBM showing a probability of a peak gust above 30 mph around 70- 80% in Lake County, southern Mendocino county, and eastern Trinity county. Uncertainty is hindering confidence at this time. Stay tuned as models begin to resolve the developing conditions. /EYS && .AVIATION...Marine stratus is beginning to scatter out and retreat to the coastline this afternoon at both terminals as the thermal trough strengthens winds offshore. Periods of broken MVFR ceilings and improved visibility are are likely to continue at ACV through 00Z, while CEC ceilings will struggle to lift to IFR amidst a light southerly wind reversal. HREF probabilities are exhibiting similar signals for a quick return to <1SM visbility's and <500 foot ceilings after sunset this evening. Transient ridging will ensure a shallow but strong marine inversion around 2000 feet remains through early Tuesday before a deep trough is expected to descend into the region. && .MARINE...Light northerly winds will continue today with slightly elevated gusts 15 to 20 knots this evening in the outer waters, although seas will remain 3 to 5 feet heading into this week. Winds and seas are expected to increase late Monday into Tuesday as a deep upper trough and associated surface low descend into the PNW. Gusts 25 to 30 knots are possible in the outer waters with seas 5 to 7 feet. Post frontal winds will become concentrated in the southern waters and nearshore of Cape Mendocino by early Wednesday and Thursday as the coastal pressure gradient tightens on the backside of the trough, with gusts exceeding 30 knots possible. As stated in the previous discussion, confidence is low at this point on gusts exceeding 30-35 knots for the latter half of the week, although short range models continue to verify the necessity for small craft condition's late Monday through late Tuesday. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 8 PM Monday to 11 PM PDT Tuesday for PZZ470. Small Craft Advisory from 8 PM Monday to 5 AM PDT Wednesday 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