textproduct: Eureka

SYNOPSIS

High pressure continues to build into the area with hot temperatures expected into early next week. The near coastal and coastal areas may start to see more marine influence over the weekend and into early next week while Trinity county is expected to see the hottest temperatures Monday and Tuesday. Cooler temperatures are possible starting on Wednesday.

DISCUSSION

High pressure continues to build in across the area and the interior is expected to see a few hot days of this heatwave. A southerly surge of clouds could make its way up to Ukiah but the likelihood of that depends on available moisture at low levels and advected stratus into the Russian River Valley and Anderson Valley. This will likely start to cool temperatures at the immediate coast and inland to areas as far as Boonville or so.

For the weekend a weak upper level trough is expected to drop down from the north. This is expected to bring some instability, but current moisture profiles look like they remain too dry for any thunderstorms. Temperatures are expected to remain more steady fluctuating somewhere around 100 in the afternoons. The winds southerly winds along the Mendocino coast are expected to slightly increase and keep the stratus in place. The high pressure is expected to keep the marine layer fairly shallow and it may mix out each afternoon. Sunday it looks fairly certain that the marine layer will be well north of Cape Mendocino as the winds get lighter.

Heat Advisories have been hoisted beginning Saturday when temperatures noticeably increaser in combination with warmer overnight low over the interior. Advisories expand in coverage southward Sunday. Monday and Tuesday high pressure continues to the strengthen over the area and is expected to some of the hottest temperatures of this heat wave. Further expansion southward or westward closer to the coast may be required.

Wednesday the high pressure is expected to start to break down and cooler temperatures are expected aloft. This will cool temperatures across the area and likely deepen the marine layer. MKK/JJW

AVIATION

Gusty winds out of the north will ease overnight. Clear skies and light winds could allow ground fog to develop into early morning Saturday at KACV. Model guidance suggests a few hours of LIFR flight categories at KACV with a probability of 25%. South of Cape Mendocino could get a light southerly push as an area of low pressure encourages low level stratus. Guidance is struggling to model much of it make it around the cape, but the subtle increase in low level moisture should allow for at least localized shallow stratus formation around Humboldt Bay. Probability for this scenario has increased to 40 to 50% after 12Z Saturday. Given the building ridge, fog visibilities will be possible. The shallow ceiling levels will also allow for quick scattering. If stratus does make it around the cape Saturday, clearing may be delayed due to light westerly flow.

MARINE

Gale strength northerlies persist in the northern waters beyond 10 nm in Zone 470. Seas up to 14 ft are likely occurring over this zone as a result. Advisory level conditions remain elsewhere from steep wind-driven seas and northerly winds of 20 to 25 kts. Steep seas are propagating into the northern inner zone 450, but the inners south of Cape Mendocino remain more sheltered from the larger northwesterly seas. Winds and seas will diminish Sunday. A small long period southerly swell moves in Monday while northerlies and short period seas restrengthen.

FIRE WEATHER

Temperatures are expected to remain hot and dry into early next. Over the weekend a shortwave moving down form the Pacific Northwest is expected to increase instability and this may lead to increased mixing heights. It doesn't look like there will be enough moisture in NW California for any thunderstorms, that is expected to remain well east and south of the area. Early next week temperatures may climb slightly more and the hottest temperatures of the heat wave are expected. Wednesday into late in the week cooler temperatures are expected. This may also bring stronger winds or possibly thunderstorms depending on how the pattern evolves. MKK.

COASTAL FLOODING

High astronomical tides are predicted from Saturday, June 13 through Tuesday June 16 for Northwest California. The combination of a high astronomical tides and long- period swells will increase the risk of minor coastal flooding around Humboldt Bay, including King Salmon and low-lying roads near Arcata Bottoms. Advisory level tidal heights of 8.8 ft at the North Spit gauge may come close to being met at the 9:53 pm high tide Friday. There is higher confidence on 8.8 to 9.1 ft tides occurring Saturday through Tuesday. /JJW

EKA WATCHES/WARNINGS/ADVISORIES

CA... Heat Advisory from 11 AM Saturday to 10 PM PDT Tuesday for CAZ102-105-116.

Coastal Flood Advisory from 9 PM Saturday to midnight PDT Saturday night for CAZ103.

Heat Advisory from 11 AM Sunday to 10 PM PDT Tuesday for CAZ108-111-117.

Heat Advisory until 10 PM PDT Saturday for CAZ113-114- 118>120.

NORTHWEST CALIFORNIA COASTAL WATERS... Coastal Flood Advisory from 9 PM Saturday to midnight PDT Saturday night for PZZ415.

Small Craft Advisory until 9 PM PDT Saturday for PZZ450-475.

Gale Warning until 9 PM PDT Saturday for PZZ470.