textproduct: Eureka

SYNOPSIS

Gusty north winds each afternoon will be the highlight of the forecast through the weekend with otherwise mild and sunny conditions. Winds will weaken with warmer conditions early this coming week.

KEY MESSAGES

-Strong north winds will continue for one more day, today into Monday, with peak gusts near 40 mph.

-Generally clear skies and dry conditions, even along shore, through early this coming week.

-Slightly cooler conditions will continue today, before warming through this coming week.

DISCUSSION

While a trough continues to move through to the north, a strong ridge of high pressure will continue to build into the region. A pressure gradient will tighten and align along shore as high pressure continues to build. This will continue to bring unusually strong northwest winds today along the coast and across most higher terrain areas of the interior. North winds will gust near 40 mph in exposed areas this afternoon. Winds will be stubbornly consistent and widespread in the afternoon, though gusts will most likely stay below advisory criteria with limited potential for impacts or damage. Marine influence will dampen for most interior areas of interior Mendocino, Trinity and Lake counties, leading to lower Min RHs in those areas today. High temperatures will remain more seasonal to cool today with temperatures rebounding into this coming week.

High pressure will push inland today and into early next week. Today, the strongest North winds will shift towards the Sacramento Valley while winds will remain breezy near shore. Winds in Lake County are anticipated to gust over 40 mph at high elevations and along the rim of the Sacramento Valley. At the same time, north winds will pull more air from the interior, promoting very dry conditions, especially far from the coast. Coastal conditions will remain mostly clear and dry.

Winds will begin to weaken Monday through mid week as high pressure settles further onshore and weakens. Conditions will remain very dry with interior highs gradually approaching the 90s by Thursday. Any HeatRisk currently minor at most. A building inversion and weaker winds will likely allow a very shallow and weak marine layer to begin reforming onshore, though offshore flow overnight will generally limit the extent of any stratus and allow it to clear during the day. Some moderate north wind will remain close to shore but be much weaker for the interior.

Models diverge on the pattern late next week. Most models show a trough of some description moving over the Pacific around next weekend with a cutoff low off the central California coast, though the relative strength of either is uncertain. Cooler temperatures are near certain, but moisture is highly uncertain.

AVIATION

VFR conditions are expected to persist through today for terminals in Northwest California. Breezy north winds will continue early this morning with winds picking up this afternoon and into the evening. Early this morning, winds will remain higher aloft, leading to LLWS for ACV and UKI. Northerly gusts from 25 to 35 knots can be expected.

MARINE

Near-Gale to Gale Force northerly winds continue across the waters today through early this coming week as the pressure gradient tightens (peaking this afternoon). Gale force gusts around 34-45 kts expected across all zones, with the strongest winds downwind of Cape Mendocino. A Gale Warning is in effect for all coastal zones. Steep to very steep, hazardous seas will continue to build with the increasing winds, peaking to 11-17 feet today.

By Monday, the pressure gradient will relax slightly with the strongest winds moving off shore. However, conditions will remain hazardous across the waters for much of the workweek with strong to gale force gusts and steep to very steep seas./ZVS

FIRE WEATHER

High pressure will shift more onshore today. Strong afternoon winds will continue, but the focus of stronger winds will shift closer to the rim of the Sacramento Valley, especially in Lake County. Winds will pull in drier air today, supporting very dry afternoon conditions in eastern Mendocino, Trinity, and Lake Counties with minimum RH near 15 percent. Overnight RH recovery will continue to worsen with upper elevation recoveries very poor by Monday morning. Winds will begin to weaken early week but very dry conditions will remain with increasing day time temperatures.

All that said, fuels generally retain a spring character. Although ERC values are forecast to jump up near record values for May, grasses remain mostly green for all locations but some of the hottest valleys in Lake and Mendocino Counties. Heavier fuels are retaining moderate moisture. Despite critical weather variables, fuels are very unlikely to support extreme fire at this time, hence a Red Flag Warning is not currently expected for these conditions in Lake, Trinity, or Mendocino Counties. This event, however, will likely push fuel towards a drier and more conducive state for fire in the coming weeks. /JHW

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Gale Warning until 3 AM PDT Monday for PZZ450-455.

Gale Warning until 10 PM PDT Monday for PZZ470-475.