textproduct: Eureka

SYNOPSIS

Temperatures will slowly continue to warm and are expected to peak on Monday. Stratus will continue to scatter out again Monday afternoon with returning coastal overcast skies in the evening. There is the possibility of some rain, drizzle, and inland thunderstorms on Wednesday or Thursday.

DISCUSSION

With a week shortwave moving trough today, accompanied with northerly winds, the coastal stratus has thinned out as mixing has broken the spell of overcast skies. This shifts the wind to more offshore by Monday morning. There are better chances of more clearing by Monday afternoon. This offshore flow should also help bring warmer temperatures to the near coastal areas 10 to 20 miles inland with many of these areas reaching into the upper 80s to low 90s. Farther inland mid 90s are expected. There is the potential that the low clouds will linger at the immediate coast and keep temperatures around 60. This will likely be the warmest day of the next week for much of the area with a Heat risk expected in the moderate range for areas of Lake and Trinity.

Tuesday an upper level low starts to approach the area and this is where model solutions start to diverge. Some of the ensemble clusters bring this low quickly north and into Washington and Oregon while the slowest solution keeps the low well off the California coast. The evolution of this low into Wednesday and Thursday will have big impacts on the forecast. This could bring the chance for Thunderstorms if the low moves onshore in northern CA. However some of the other solutions could keep hot temperatures over the area. Late in the week the models are showing zonal flow developing over the west coast. There are still some big differences whether there will be some weak ridging and dry weather or the remnants of the upper level low continuing to move through the area. Overall confidence is below normal in the extended period.

AVIATION

Steady clearing is being observed along the North Coast today. MVFR ceilings expected to give way to VFR from 21Z through 03Z (+/-1hr). Gusty north winds along the coast will increase mixing and the chance for light Low Level Turbulence. Forecast confidence is moderate for prolonged clearing at KCEC (~50%) through the night. KACV however is expected to have MVFR ceilings (>80%) with periods of IFR (~70%) early in the morning. Inland terminals will continue with VFR conditions and daily terrain focused winds. Gusts forecasted mostly for ridgetops as minimal mixing reaches the valley floor, especially at KUKI. DS

MARINE

A surface high pressure center in the eastern Pacific Ocean will flow northward today strengthening the surface pressure gradient as it interacts with a low pressure center in Baja. The response to this strengthening will be a steady increase of northerly winds this afternoon. Most of the coastal waters can expect strong breezes this afternoon up to 30kts. Areas downwind of Cape Blanco and Cape Mendocino are forecasted to have gale force gusts, yet the forecasted coverage of these winds is minimal enough to not warrant an official Gale Warning for the outer waters. Winds are expected to remain at least moderately breezy through Monday afternoon before sustained gentle breezes develop Tuesday.

Short period seas have been increasing in height through the morning, especially in the southern waters. These waves have warranted small craft advisories to be hoisted for zones 470, 475, and 455 in turn. Northerly short period waves will mix with a mid period westerly swell through the early week. Tuesday evening through Thursday, this westerly swell will dominate the coastal waters. DS

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 3 AM PDT Monday for PZZ455.

Small Craft Advisory until 9 PM PDT Monday for PZZ470-475.