Marine Weather Net

Point St. George to Point Arena between 150 and 250 NM Offshore Forecast


TONIGHT

N
WINDS
20 - 25
KNOTS

SUN

N
WINDS
15 - 25
KNOTS

SUN NIGHT

N
WINDS
15 - 20
KNOTS

MON

N
WINDS
15 - 20
KNOTS

The Marine Weather Forecast In Detail:
PZZ920 Forecast Issued: 248 PM PDT Sat Jul 13 2024

Tonight...N Winds 20 To 25 Kt. Seas 7 To 12 Ft.
Sun...N Winds 15 To 25 Kt. Seas 6 To 10 Ft.
Sun Night...N Winds 15 To 20 Kt. Seas 5 To 8 Ft.
Mon...N Winds 15 To 20 Kt. Seas 5 To 7 Ft.
Mon Night...N Winds 15 To 20 Kt. Seas 5 To 7 Ft.
Tue...N Winds 10 To 20 Kt, Becoming 10 To 15 Kt. Seas 5 To 7 Ft.
Tue Night...N Winds 5 To 15 Kt. Seas 5 To 6 Ft.
Wed...N To Nw Winds Less Than 10 Kt, Becoming W To Nw. Seas 5 To 6 Ft.
Wed Night...W To Sw Winds 5 To 10 Kt. Seas 4 To 6 Ft.
Thu...W To Sw Winds 5 To 10 Kt. Seas 4 To 5 Ft.
Thu Night...W To Sw Winds 5 To 10 Kt, Becoming W To Nw. Seas 4 To 5 Ft.
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Area Forecast Discussion
National Weather Service Eureka CA
257pm PDT Sat July 13 2024

Synopsis
A break from extreme heat is expected yet, with that comes the threat for potential thunderstorms as a low pressure system offshore spins monsoonal moisture and instability to the area. Southerly winds and moisture could also cause a few lightning strikes this evening as day heating lingers.

The trend for temperatures in the hundreds will begin to wane for the interior as the anticyclonic mass shifts to the east, relieving the area of the ongoing oppressive heat regime. An upper level low, which appears to be cutoff, is bringing a characteristic reprieve from the heat yet introduces monsoonal moisture to the PACNW as the cyclonic motion also brings a familiar pattern associated with thunderstorm activity as southerly winds become pronounced. This raises the threat of dry lightning as model soundings are showing a strong signal with inverted V profiles, with regards to temperature and dew point, that are quantifiable dry as they spread towards the surface.

Considering the abundant lighting acclivity over the Sierras yesterday and the elevated instability (MUCAPE) from the soundings, a red flag warning has been hoisted for the potential threat of dry thunderstorms over the interior regions of Lake, Eastern Mendocino, and Trinity counties. This RFW will begin in the early Sunday morning hours, 2am through 10pm Sunday, as we consider dry fuels, the recent heat wave and the familiar set up as ingredients for a dry lightning event.

Also, Isolated thunderstorms are possible this afternoon over the far interior mountains in the previously outlined regions. Chances will increase tonight through Sunday (15-20%) as discrete areas of PVA rotate in off the low and the moisture within interacts with the higher terrain. Chances for dry thunderstorms will be highest around the Yolla Bolly area and Northeast Trinity County on Sunday, but coverage may expand west, and eastern Humboldt cannot be ruled out for at least some gusty convective cells.

The Four Corners region high will continue to weaken into next week dropping most of the warmer interior valleys below 100. There are indications that the high will be steered back towards the west as a strong upper level low meanders north towards British Columbia, swinging the high towards the west coast. /JJW /EYS

Marine
Winds and seas will continue to diminish this afternoon. Advisory level winds and wind waves will become confined to the northern outer waters by this evening before expiring early Sunday morning. Otherwise, steep seas expected to diminish below 10 feet by Sunday afternoon. Isolated gusts 15-25 knots are still possible in the far NW corner of the outer waters through early next week. The coastal pressure gradient will continue to be hindered by an upper shortwave driving a weak area of low pressure up the NorCal coast, interrupting the offshore high. Weak southerlies expected to develop across all zones mid- next week as the low tracks north. High pressure expected to redevelop late week, allowing northerlies to resume.

Fire Weather
Models are converging on a plume of monsoonal moisture arriving this afternoon. Moisture along with daytime heating will allow for greater instability and a chance of dry thunderstorms this evening in Lake, eastern Mendocino, and eastern Trinity counties. A Red Flag Warning has been issued for zones 283 and 277 for potential coverage of dry thunderstorms and gusty outflow winds.

With ample forcing, moisture and currently looking like sufficient elevated instability, ingredients for thunderstorms are looking better late tonight through Sunday for portions of Lake, Mendocino and Trinity Counties. Eastern Humboldt cannot be ruled out for at least some gusty convective cells. Model soundings reveal the classic inverted V signature, indicative of dry showers and likely thunderstorms. There is still some uncertainty for available instability for thunderstorms, but any thunderstorms or stronger convective showers that form with be capable of strong and erratic outflow winds. As moisture begins cutting off on Monday, an additional isolated shower or thunderstorm will still be possible Monday afternoon over Trinity County. JJW/JB/EYS

.EKA WATCHES/WARNINGS/ADVISORIES... CA...
Heat Advisory until 9pm PDT this evening for CAZ104-106- 112.

Excessive Heat Warning...til 9pm PDT this evening for CAZ105-107-108-110-111-113>115.

Red Flag Warning from 2am to 10pm PDT Sunday for CAZ277- 283.

NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 3am PDT Sunday for PZZ450-470.

Small Craft Advisory until 9pm PDT this evening for PZZ475.