Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
688 FXUS66 KEKA 231151 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 451 AM PDT Thu May 23 2024 .SYNOPSIS...Cooler than normal temperatures are forecast for the interior through Saturday. Dry weather with locally gusty winds are expected to continue today before a trough aloft moves over on Friday bringing a low possibility for light rain. && .DISCUSSION...Low clouds over Humboldt Bay/Eel delta and adjacent river valleys will most likely clear out by late morning. Otherwise, just transparent high clouds today. Early morning temperatures were running much cooler compared to last night with the usual cold spots like Larabee valley and Hayfork in the lower to mid 30`s. Meanwhile, in Lake County early morning temperatures were much warmer, 50-60F. A few wind-prone ridges remained quite gusty overnight (35-50 mph) while valleys sites and coastal areas decoupled and winds were nearly calm (<3 mph). A frost advisory remains in effect til 8 AM for valley locations below 3000 feet MSL with early morning minimums around 36F or less. Temperatures will remain below normal on Friday and Saturday as a weak upper trough remains over the area. Normal high temps are about 80F for Willow Creek, Weaverville and Ukiah. A shortwave trough in NW flow aloft will probably bring a push of shallow moist air to the North Coast as early as Friday evening and as late as early Saturday. Coastal fog and drizzle are highly probable. Also, HREF indicates some light rain possible (10-20% chance) for the interior mountains (mainly Trinity) on Friday. Deeper moist layer will result in thicker cloud cover for the interior by early Sat. Cloud cover and cool-damp marine air will aid with the cool down of daytime temperatures on Saturday. Broad and flat ridging aloft will build back on Sunday and hold into early next week. Above normal 500mb heights and warmer 850mb temperatures will likely result in above normal interior temperatures through the end of next week. How warm and the rate/progression of the warming are not certain. A weak trough may temporarily disrupt the warm up around mid week, but NBM GUIDANCE remains firm and continues to support the idea of above normal max temps (>80F). High temps may even reach or exceed 90F for the warmest inland valleys by the end of next week. Coastal areas will not warm up with cool-damp marine air severely moderating high and low temperatures. DB && .AVIATION...ACV/CEC...Weakness in the northerly winds around Humboldt Bay allowed for a brief band of MVFR level stratus to make in into ACV before scattering out early Thursday morning. Shortwave troughing will move in tonight, and the chances for stratus formation along the coast will begin to increase ahead of it in a coastal eddy. Probability of ceilings below 1000 ft AGL will quickly increase after 5Z Friday (50 to 70% over the coastal terminals), with LIFR CIGS and patchy fog probable along the coast and coastal terminals through the end of this 12Z TAF period Friday morning. Closer to the coast, lingering 25kt northerly winds aloft will create minor low level wind shear through 15Z this morning. UKI...VFR conditions will prevail through this period as mid to upper cloud cover increase ahead of a shortwave trough. WNW to NW winds will generate some gusts this afternoon in the 20 kt area. && .MARINE...Northerly winds continue today, strongest in the southern waters, while the northern zones begin trending down. Winds accelerated in the expansion fan south of the cape will increase to Gale strength gusts this afternoon. These winds will move into the inner southern waters through the afternoon as well, but coverage is more limited. A passing shortwave trough will briefly ease the northerlies on Friday before they increase again Friday night. The northerlies will then become more focused in the southern zones south of Cape Mendocino through the weekend. Seas will be 6 to 9 feet through tonight, dominated by short period NW seas. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... Frost Advisory until 8 AM PDT this morning for CAZ106>108. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 11 AM PDT this morning for PZZ450-470. Small Craft Advisory until 9 PM PDT this evening for PZZ455- 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