textproduct: Eureka

SYNOPSIS

Moderate to major HeatRisk will continue across the interior through the early week, though coastal areas will begin to see increase marine influence and cooling. The heat wave will break down later in the week.

KEY MESSAGES

- Temperatures will begin to peak with moderate to major HeatRisk through early week.

- Shallow marine influence growing along shore may help suppress some temperatures.

- Cooling trend for inland areas mid to late next week.

DISCUSSION

High pressure ridging continues to dominate across the area with the strongest focus shifting further north across Humboldt and Trinity Counties Sunday and into Monday. High temperatures will continue to be above average, though not record breaking. High temperatures will slightly weaken in Lake and Mendocino Counties Sunday thanks to increased marine influence being pulled upward in southerly wind overnight. Meanwhile, interior valleys for the northern half of the area will most likely crest over 100 today with the hottest valleys having a 50% chance of touching 105. These temperatures constitute a generally moderate HeatRisk with some areas of major risk for the warmest valleys. Shallow marine influence may bring a few hours of clouds tot he coast around sunrise, but otherwise clear skies will continue to promote highs near 70 along shore, though afternoons ea breeze will bring a quick end to any strong warming.

Similar conditions will persist through Monday. Come Tuesday, heat will continue to peak for the northern half of the area, but weakening marine influence further South will push HeatRisk back toward major in Mendocino and Lake Counties, likely bringing another need for heat advisories in those areas around Tuesday.

High pressure will begin to weaken late in the week 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. Most models currently suggest the trough is too weak to tap into any tropical moisture. While some showers or very weak storms could be likely, currently profiles are not favorable for widespread convection. /JHW

AVIATION

Dry air and high pressure continue to support VFR conditions all across the area. There is as of early Sunday morning a very shallow layer of marine fog trapped along shore south of Cape Mendocino. Southerly winds overnight might be able to push the fog into the Russian River Valley and north along shore by Sunrise, but overall chances are low (less than 35%) of LIFR or IFR conditions. Any fog will quickly scatter during the day back to VFR conditions with marine influence more likely to push onshore Sunday night. /JHW

MARINE

High pressure broadening over the area has continued to weaken the nearshore pressure gradient. North winds will continue to weaken Sunday with calm to gentle winds in all waters through at least Monday. Sea will also fall with all short period seas falling below 6 feet by mid Sunday morning. Beyond wind waves,a minor southerly swell no more than 3 feet will continue to impact the waters.

High pressure rebuilding over the eastern pacific will help restrengthen north winds mid week. Strong winds will first build in the northern waters and then spread south, the the southern inner waters especially will likely remain mostly calm. Near gale conditions are most likely for outer northern waters by Wednesday. Short period sea will follow the winds and dominate the sea state. /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 RAW stations likely to reach near the the percentile by midweek, 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 by midweek.

Long term models show a weak trough crossing the area late in the week. Such a pattern could produce thunderstorms. Most models, however, currently show moisture profiles insufficient to really drive convection. Current thunder chances are less than 10 percents with the highest chances in NE Trinity County. That said, any showers that do form over high terrain are most likely to be dry given the setup and preceding conditions. /JHW

COASTAL FLOODING

High astronomical tides are predicted from Saturday, June 13 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

EKA WATCHES/WARNINGS/ADVISORIES

CA... Heat Advisory until 10 PM PDT Tuesday for CAZ102-105-116.

Coastal Flood Advisory until midnight PDT tonight for CAZ103.

Coastal Flood Advisory from 9 PM Sunday to 1 AM PDT Monday for CAZ103.

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

NORTHWEST CALIFORNIA COASTAL WATERS... Coastal Flood Advisory until midnight PDT tonight for PZZ415.

Coastal Flood Advisory from 9 PM Sunday to 1 AM PDT Monday for PZZ415.

Small Craft Advisory until 3 AM PDT Sunday for PZZ450.

Small Craft Advisory until 9 AM PDT Sunday for PZZ470.