textproduct: Eureka

SYNOPSIS

Moderate to major HeatRisk will continue across the interior through Tuesday, though coastal areas will still see marine influence and cooling. The heat wave will break down beginning Wednesday.

KEY MESSAGES

- Temperatures begin to slightly ease but remain above average Tuesday. - Cooling trend beginning to build in Wednesday.

- Slight (15%) thunderstorm chances over the eastern interior Thursday and Friday afternoons.

DISCUSSION

High pressure ridging continues to dominate across the area with the strongest focus persisting over Humboldt and Trinity Counties today with valley high temperatures again around 100. High temperatures will continue to be above average, though not record breaking. High temperatures rebound again today for the southern half of the area thanks to weakened south wind. Ukiah returned to near 100 Monday afternoon. Conditions will ease by just a couple degrees Tuesday, but these temperatures still constitute a generally moderate HeatRisk with some areas of major risk for the warmest valleys. Heat has made for a robust but very shallow marine layer that has blanketed the immediate coast, though clearing Monday was slight better than Sunday.

High pressure will begin to weaken more by Wednesday with interior highs pulling back into the mid 80s. Most deterministic models show weak trough pushing onshore around Thursday. This trough will definitely cool conditions and help deepen marine influence along shore, creating a more persistent and further reaching marine layer. COmpared to p[previous runs, more high resolution models show a weak moisture plume moving up the Sacramento valley. Interacting with the trough, this could (20% chance) produce elevated, mostly dry thunderstorms in eastern Mendocino and Trinity Counties on Thursday and Friday afternoons. /JHW

MARINE

Mostly calm conditions currently bridge across all waters. High pressure rebuilding over the eastern pacific will help restrengthen north winds beginning late this evening and into mid week. Strong winds will first build in the northern waters and then spread south. Near gale conditions are most likely for outer northern waters by late Tuesday. That said, the inner waters will most likely remain mostly calm. Short period sea will follow the winds and dominate the sea state. Despite calmer winds near shore, just enough steep short period waves will likely emanate into the inner waters to justify small craft advisories for steep seas around Wednesday. /JHW

COASTAL FLOODING

High astronomical tides are predicted through Tuesday June 16 for Northwest California with the highest tide just before midnight each evening. High tides peaked around 9 feet on Saturday night. Weakened north winds and higher astronomical tide will likely push the tide even slightly higher Sunday night near 9.1 feet. High tides will cause minor coastal flooding round Humboldt Bay, including King Salmon and low- lying roads near Arcata Bottoms. /JHW

FIRE WEATHER

An ongoing heat wave has helped rapidly dry fuels. Interior high temperatures have been reaching near 100 with RH generally between 15 and 25 percent. Overnight RH recovery has also been poor with thermal belts with mid and upper elevation nighttime RH only around 50 percent. ERC has rapidly increased across the board with most RAWS already reaching near the 90th percentile, even close to shore. That said, the general lack of wind will continue to suppress the risk of any fast moving fires. Hot and dry conditions will weaken beginning Wednesday.

The pattern late week is coming more into focus. Some longer range high resolution models show a more well formed though weak moisture plume moving up the Sacramento Valley late week. Combined with the the passing upper level trough, such a setup is likely to create Thunderstorms over high terrain Thursday and Friday afternoons and evenings. The greatest potential will be in NE Trinity County (20% chance) with lower chances (10%) around the Yolla Bollys. Any storms that form will be mostly dry. Given the preceding heat wave, any lightning is likely to be efficient with possible new fire starts.

EKA WATCHES/WARNINGS/ADVISORIES

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

Coastal Flood Advisory from 10 PM this evening to 2 AM PDT Tuesday for CAZ103.

NORTHWEST CALIFORNIA COASTAL WATERS... Coastal Flood Advisory from 10 PM this evening to 2 AM PDT Tuesday for PZZ415.

Small Craft Advisory from 3 PM Tuesday to 3 AM PDT Wednesday for PZZ450.

Small Craft Advisory from 9 PM this evening to 8 AM PDT Tuesday for PZZ470.

Gale Warning from 8 AM Tuesday to 9 AM PDT Wednesday for PZZ470.

Small Craft Advisory from 3 AM Tuesday to 9 AM PDT Wednesday for PZZ475.