textproduct: Eureka

AVIATION UPDATE (18Z)

Coastal stratus remains across the entire western seaboard today. expected IFR/LIFR conditions for most of the day along coastal terminals. Slight clearing is possible, yet not expected. If it does clear, overcast skies will return later this afternoon between 02-04Z for most of the North Coast. Winds will remain light (<08kt) for most of the day along the coast. Directions will be dictated by coastal eddies forming and migrating through the day. Overcast skies are expected to dissipate around noon for Saturday, especially near KACV with steady light to moderate winds tomorrow out of the NW. Inland areas are expected to remain VFr with gusty afternoon winds developing. Upslope winds will form through the morning and midday before NW winds dominate NW CA.

PREV DISCUSSION

/issued 1217 AM PDT Fri Aug 7 2026/

KEY MESSAGES...

* Moderate to major heat risk continues through the weekend for much of the interior peaking on Saturday in most areas.

* Temperatures diminish slightly next week, but most areas remain the upper 90s to around 100 through mid-week.

* Increased winds and low relative humidity will elevate fire danger this weekend.

* Coastal stratus to continue for much of the North Coast Friday with better chances for afternoon clearing over the weekend.

SYNOPSIS...Persistent high pressure aloft will remain through the weekend. Inland areas continue to see above normal temperatures through the weekend bringing moderate to major heat risk. Coastal areas will remain mostly overcast Friday with better chances of clearing over the weekend.

DISCUSSION...A steady ridge of high pressure remains entrenched over the west coast leading to warm to VERY hot temperatures for the inland areas. Most inland valleys can expect high temperatures between 100-110F through the weekend. The coast continues to offer some relief from this heat. Offshore stratus is blanketing much of the western seaboard from the Mexican boarder up through Oregon. Temperatures will struggle to reach 65F for coastal communities due to this compressed marine layer. However, above average SSTs will limit the likelihood of any true daytime fog.

Some warming is expected Friday and Saturday across the interior increasing the HeatRisk with moderate to major HeatRisk now being indicated. The heat is expected to peak on Saturday, particularly over Lake County, where conditions are on the edge of warranting an excessive heat warning instead of only an advisory. Regardless, this persistent heat will be dangerous for anyone working outside and everyone in the interior portions of all of Northern California should be drinking plenty of fluids and taking breaks to avoid heat stroke.

A couple passing shortwaves on the northern periphery of the ridge will tighten the pressure gradient over the region allowing for a stronger onshore sea breeze each afternoon and evening. With very dry conditions across the interior this will result in increase fire weather concerns. For more details, see the fire weather section below.

The ridge will finally see some weakening early next week as a weak trough settles over the west coast. This should allow temperatures to cool several degrees back to around normal for this time of year. /RPA

MARINE...Light to moderate northerly winds are in place over most of the coastal waters at this time with only a few light southerly winds persisting along the northern Humboldt and Del Norte coasts.

Friday and into the weekend, a more uniform regime of northerly winds are forecast to return to the area. Gales are possible over the weekend into early next week with the likelihood of gusts >30kts over 80% for most of the outer waters from Saturday through most of next week. Very steep seas will build in response to this increasing winds and gale watches have been issued for the outer water zones for portions of the weekend.

FIRE WEATHER...Conditions are expected to remain hot and dry through through the weekend. This heat wave will likely cause an increase in fire risk as the fuels dry. This weekend, the synoptic weather pattern is likely to change ever so slightly. This change will be felt by an increase in the likelihood of stronger valley winds each afternoon. The primary areas of concern are in the eastern Trinity River valley and on the eastern side of Clear Lake in Lake County. The duration of the stronger westerlies each afternoon should be limited to less than the required 8 hours for red flag warnings. Thus, no fire weather watch been issued at this time but a headline has been introduced into the fire weather forecast product.

BEACH HAZARDS...Sea levels continue to run approximately 0.8 ft above the predicted tide level in Humboldt Bay. Tides will become more amplified early next week following the normal lunar cycle. The predicted tide at the North Spit is 7.95 ft MLLW at 10:21 pm on Monday the 10th and then 7.99 ft MLLW at 11:17 pm on Tuesday the 11th. If the tide continues to run at around 0.8 ft above predicted, this could result in minor coastal flooding around Humboldt Bay with minor impacts in King Salmon and possibly a few other locations around the bay.

EKA WATCHES/WARNINGS/ADVISORIES

CA... Heat Advisory until 10 PM PDT Sunday for CAZ108-116-117.

Heat Advisory until 10 PM PDT Sunday for CAZ110-111-113-114- 118>120.

Heat Advisory from 10 AM Saturday to 10 PM PDT Sunday for CAZ112.

NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 5 PM this afternoon to 3 PM PDT Saturday for PZZ470.

Gale Watch from Saturday afternoon through Monday morning for PZZ470-475.

Small Craft Advisory until 3 PM PDT Saturday for PZZ475.