textproduct: Eureka

SYNOPSIS

Temperatures will finally begin to pull back midweek with only minor HeatRisk across the area. Temperatures will bottom out around Friday in the low 80s with a slight chance of dry thunderstorms.

KEY MESSAGES

- Temperatures ease through the end of the week with only minor HeatRisk

- Slight chance (10-20%) of dry thunderstorms over high terrain Thursday and Friday evenings.

- A lifting but persistent marine layer forming along shore.

DISCUSSION

High pressure and the associated ongoing heatwave peaked for one finale time today with many interior highs still in the mid-90s and mostly moderate HeatRisk. For the coast, a slightly weakening marine inversion combined with stronger northerly wind help clear skies, though a shallow marine layer is most likely to reform overnight into Wednesday.

Conditions will begin to cool more rapidly Wednesday and especially Thursday as a broad trough approaches the area. The trough will help generate some upper level clouds and pull in more marine influence, helping to drop interior temperatures into the 80s and creating a more lifted marine layer along the coast.

The trough will also help increase upper level instability. Combined with a moisture surge up the Sacramento Valley, there is a chance (10-20%) of isolated, mostly dry thunderstorms over eastern Trinity and Mendocino Counties both Thursday and Friday evenings. Otherwise, temperatures will bottom out Friday with slight warming into the weekend. /JHW

MARINE

High pressure pushing east contrasting with approaching trough has helped generate strong to gale force north winds int he outer waters today. Short period seas have rapidly steepened in response. In contrast, wind shave remain much more gentle near shore, though wave energy emanating in from the outer waters has still helped create moderately steep seas up to 10 feet in the inner waters. These conditions will persist through Wednesday before winds push further away from shore Thursday and Friday. /JHW

COASTAL FLOODING

High astronomical tides are predicted through Tuesday June 16 for Northwest California with the highest tide just after midnight each evening. High tides have been peaking around 9 feet. High tides will cause minor coastal flooding round Humboldt Bay, including King Salmon and low- lying roads near Arcata Bottoms. /JHW

FIRE WEATHER

The current heatwave has helped rapidly dry fuels, pushing ERC values close to 90 percent. Although conditions will begin to ease midweek (highs pulling back into the 80s and RH above 25 percent) the lingering effects of heat on fuels will remain for several days. Continued gentle terrain winds will limit rapid fire spread.

The largest concern is the increasing potential for dry thunderstorms Thursday and Friday evening. There remains high uncertainty due to the broad nature of the trough and weakness of the general moisture pulse. The greatest chances (10-20%) for thunderstorms will be over high terrain in Trinity and Mendocino Counties. Though storms will be weak and isolated, ignitions are likely given the current fuel status. /JHW

EKA WATCHES/WARNINGS/ADVISORIES

CA... Heat Advisory until 10 PM PDT this evening for CAZ102-105- 108-111-114-116-117.

Coastal Flood Advisory from 11 PM this evening to 3 AM PDT Wednesday for CAZ103.

NORTHWEST CALIFORNIA COASTAL WATERS... Coastal Flood Advisory from 11 PM this evening to 3 AM PDT Wednesday for PZZ415.

Small Craft Advisory until 9 PM PDT Wednesday for PZZ450.

Gale Warning until 9 PM PDT Wednesday for PZZ470.

Small Craft Advisory until 3 PM PDT Wednesday for PZZ475.