Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
209 FXUS66 KEKA 162157 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 257 PM PDT Thu May 16 2024 .SYNOPSIS...Interior temperatures are forecast to trend down as gusty northwesterly breezes increase over land areas this weekend. More substantial cooling will be possible around mid week. && .DISCUSSION...Visible satellite imagery showed stratus covering coastal areas from the California-Oregon border southward to Gualala. Onshore breezes and marine air intrusion has resulted in much more cooling for some of the the coastal river valleys and coastal areas that warmed up yesterday (down 15 to 30F). 24 hour temperature change in Trinity and NE Mendo were much less dramatic (down 1 to 5F). Interior temperatures are forecast to generally continue on a downward trend Friday-Sunday. A transient 500mb shortwave trough will move across the Pac NW tonight into early Friday and force the ridge aloft southward. A decaying surface front will drag across the area early Friday and some drizzle will possible (10% chance) for mostly coastal northern Humboldt. A deeper trough will follow by Sunday and high temperatures are forecast to cool to more pleasant levels or about normal for mid May (72F-82F). NW winds are forecast to be gusty (gusts 20-35 MPH) per NBM guidnace too. Uncertainty increases Tue into Wed on how fast temperatures will cool and to what magnitude as a deeper and relatively dry trough moves into the Pac NW. Main impacts will cooler temps, breezy NW and W winds and perhaps some early morning frost in the interior (mostly Trinity) valleys around mid week. NBM probabilities for 0.10in in 24 hours are still hovering around 10-20%, primarily for Del Norte, northern Humboldt and mountains of Trinity around mid week. Thus, even though NBM precip chances have decreased to 10% or less, light precip is still not completely out of the realm of possibilities around mid week. Greater uncertainty arises latter next week with perhaps a deeper and wetter trough digging offshore the NW California coast. This is consistent with the overall pattern we have been in this spring and would not be too surprised if we get another bout of cool weather and rain. DB && .AVIATION...Stratus has remained stubborn along the coast with LIFR to IFR conditions persisting at CEC and ACV for much of the day so far. CEC has cleared any should stay clear through sunset, accompanied by gusty northerly winds of up to 30 knots. These winds will ease slightly after sunset. ACV may also see some temporary clearing late this afternoon, but stratus is expected to come back in later tonight. IFR to LIFR conditions will continue overnight along the coast. UKI experienced low ceilings this morning from advection fog from the south. Conditions tonight south of Ukiah are similar to that of last night, so the threat is there for some low ceilings early morning in UKI. Any fog that makes it`s way inland will lift by mid- morning. JB && .MARINE...Northerly gales continue in the northern outer waters, while hazardous seas continue in the northern waters and the southern outer waters. Winds will increase further Friday morning with gales expected in both the northern and southern outer waters, with gusts up to 40 knots possible. Steep to hazardous seas spread to all waters Friday. Winds will diminish slightly Friday night into Saturday morning, before increasing again Saturday afternoon with widespread gales in the outer waters. This cycle will continue into mid next week. Winds will be near-gale or gale, particularly in the outer waters, through the early week, though there is a sigh of some weakening by mid next week, at least to below gale force. JB && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Hazardous Seas Warning until 3 PM PDT Friday for PZZ450. Gale Warning until 3 AM PDT Saturday for PZZ470. Hazardous Seas Warning until 3 AM PDT Friday 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