Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
535 FXUS66 KEKA 211139 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 439 AM PDT Fri Jun 21 2024 .SYNOPSIS...Dry weather is expected for the foreseeable future. Interior heat will build this weekend, before decreasing steadily to normal conditions by the end next week. && .DISCUSSION...The extensive field of stratus along the coast is continuing is reign this morning breaking only south of the King Range due to downsloping winds leading to compressional warming. This marine layer is expected to deteriorate throughout the day before returning to its overcasting glory by the evening. Certain areas sheltered from the direct onshore wind will see the most sky clearing. The atmospheric mechanisms leading to this stratus formation should remain unwavering through the weekend. The most common ways this layer degrades is when the coastal inversion lifts and/or weakens or stronger offshore flow develops. So far there are no clear signals for either. Thus the reasoning for the continuation of the stratus and grey skies. Otherwise, interior temperatures will be hot today and tomorrow with 100F degree heat probable for the warmest interior valleys. Today will most likely be the hottest for Trinity County while Saturday will most likely be the hottest day with temperatures topping out around 98-104F in Lake and interior Mendocino counties. The heat is forecast to diminish on Sunday, but it will still be hot with highs in the upper 90`s to around 100F, mostly in Trinity county. NBM remains consistent with temperatures trending down around mid next week as another trough digs offshore over the NE Pacific and eventually approaches the west coast. There are signs for stronger ridging from the SW with 500mb heights pumping up above 588DM early next week. Thus, the downward trend of temperatures may end turning into another warm up with high temps around 100F or more for out hot interior valleys. Ensemble members are showing a stronger signal of warm temperatures persisting through Thursday before another upper- level trough enters our area next Friday. Otherwise, interior temps will most likely remain well above normal next week. DS/DB && .AVIATION...12Z TAF ACV/CEC...A shortwave trough is passing SE early this morning. The marine layer deepened quite a but in response, but a shallow, low- level inversion has formed, allowing for LIFR CIGS. As the trough moves away, heights will very quickly rebound. Soundings reflect this with ceiling heights becoming compressed and lowering under the strengthening low level inversion. LIFR CIGS and perhaps TEMPO fog will remain in the TAFs for the 12Z issuance as the pattern dictates, but the deepened state and shortwave influence is producing variability up to IFR and even MVFR levels. Statistical guidance (MOS) has not been handling this setup well given the season which usually more frequents fog. Subsidence behind the departing shortwave may offer opportunity for scattering before the stratus fills back in at a shallower level this evening, with higher probability of fog into Saturday morning. UKI....The seasonally anomalous deepened state of the marine layer nearly allowed for intrusion over the mountain from the west before some lowering occurred and thwarted the stratus advance...thus VFR will prevail at this terminal. Northwest winds will likely produce the occasional gust this afternoon in the 15 kt area. Not expecting much advance of stratus up the valley from the south tonight, but MOS guidance does show very light southerly winds at the terminal tonight. && .MARINE....Northerly winds will be on the increase today. Enhanced winds around and south of Point St George and Cape Mendocino will reach 30 kts this afternoon and through tonight. Coverage and strength will be greatest in the waters around Cape Mendocino where gusts up to 40 kts are forecast. A Gale Watch is out in the Southern Outer zone 475. These winds will slowly ease some on Saturday. The southern zones will still see winds up to 30 kts, but with less coverage. The northerlies will increase again on Sunday with gale conditions expanding again in the southern zones. Steep, wind-driven seas will continue to propagate into the inner waters and warrant Small Craft Advisories. The extended forecast holds a late season NE Pacific trough which would briefly nudge the stronger northerly winds farther south mid next week. /JJW && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 9 AM PDT Saturday for PZZ450. Small Craft Advisory until 10 AM PDT Sunday for PZZ455. Small Craft Advisory until 6 PM PDT Saturday for PZZ470. Small Craft Advisory until 3 PM PDT this afternoon for PZZ475. Gale Watch from 3 PM PDT this afternoon through Saturday morning 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