Marine Weather Net

Cape Mendocino to Point Arena CA out 10 NM Marine Forecast


5 - 15


5 - 10


5 - 15


10 - 15

The Marine Weather Forecast In Detail:
PZZ455 Forecast Issued: 458 PM PDT Tue Jul 27 2021

Tonight...Nw Winds 5 To 15 Kt. Waves Nw 4 Ft At 8 Seconds... And S 2 Ft At 14 Seconds. Scattered Showers.
Wed...W Winds 5 To 10 Kt. Waves N 4 Ft At 5 Seconds...And S 2 Ft At 13 Seconds.
Wed Night...S Winds 5 To 15 Kt. Waves N 4 Ft At 5 Seconds.
Thu...W Winds 10 To 15 Kt. Waves N 3 Ft At 5 Seconds.
Thu Night...N Winds 5 To 10 Kt. Waves Nw 4 Ft At 5 Seconds.
Fri...Nw Winds 5 To 10 Kt. Waves Nw 4 Ft At 5 Seconds.
Sat...Nw Winds 5 To 10 Kt. Waves N 4 Ft At 5 Seconds.
Sun...Nw Winds 5 To 15 Kt. Waves Nw 5 Ft At 6 Seconds.
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Area Forecast Discussion
National Weather Service Eureka CA
500pm PDT Tuesday July 27 2021

Radar and satellite data indicate showers for Northern Mendocino, Humboldt, Trinity and Del Norte counties.

SYNOPSIS...Temperatures across interior portions of northwest California will steadily warm during the week, with high temperatures in the low 100s probable by Friday afternoon. Conditions will then cool during the weekend into early next week. Otherwise, showers will dissipate across the region this evening. Additional thunderstorms may occur across the interior mountains Thursday and Friday.

A zone of mid/upper-level frontogenesis aided in thunderstorm development along the coast this morning. However, that phenomenon is weakening and gradually shifting north of the region. Thus, lingering shower activity is forecast to dissipate during the evening. A pronounced area of heat centered over the Intermountain West is then forecast to expand westward toward NWRN CA through Friday. Interior valley temperatures will experience a warming trend as a result, with highs in the 90s to near 100 on Thursday, followed by probable low 100s Friday afternoon. The heat is then forecast to be shunted east away from the area this weekend into early next week due to the influence of an upper trough approaching the area from the west over the NERN PAC.

Otherwise, model guidance shows monsoon moisture lingering near NRN CA this week. That moisture combined with strong surface heating Thursday and Friday afternoon, as well as steep lapse rates aloft and subtle lobes of ascent in the upper-levels, will aid in mountain thunderstorm development during the afternoon and evening hours on Thursday and Friday.


AVIATION...The marine layer has started to mix out this afternoon with the weaker inversion from the cooler temperatures aloft. This has brought VFR conditions many of the coastal areas. There are also some higher level convective clouds that are making it difficult to determine the extent of stratus that is lingering.

In addition to this a subtle shortwave is moving up from south. As of 1pm it is over the Sonoma/Mendocino county border and will be moving north into Mendocino county later this afternoon. This is not expected to bring more than a few sprinkles and some mid level clouds to KUKI. There is a small chance there could be a lightning strike or two, but currently this is not in the forecast. This wave will move north this evening and eventually onto the north coast. This will likely help to keep the marine layer broken up for longer into evening. Later tonight the marine layer is expected to settle back into place with LIFR conditions, although confidence is low on this. Wednesday models are generally indicating that skies will clear out at the coast at least for a period of time in the afternoon. MKK

MARINE...The winds and seas continue to diminish this afternoon. Currently there are three swells, a southerly swell of around 2 feet at 14 seconds (mainly in the southern waters), a northwest swell of 3 feet at 8 seconds and a lingering wind driven wave of 2 to 3 feet at 4 seconds. Northwest winds remain around 5 to 15 kt. These are generally below small craft advisory criteria so will allow this to expire.

Tonight winds will be out of the north at around 10 to 20 and seas will be fairly steep at 3 to 6 feet. This is expected to bring conditions close to small craft advisory levels of 22 kt and 6 foot steep seas, but currently they are not expected to reach that. These winds and waves are generally expected to persist through the remainder of the week.

Winds will increase slightly for the weekend and into early next week with winds over the outer waters rising closer to 20 kt. There are still quite a few differences in the model winds for this time period.

The longer period southerly swell is expected to diminish over the next several days and seas will be mainly wind drive for the weekend and into early next week. MKK

Fire Weather
Isolated to scattered thunderstorms will be possible across portions of Trinity and northeast Mendocino Counties Thursday and Friday afternoon. Model forecast soundings show the convective environment will be characterized by a deeply mixed boundary layer and very large temperature-dewpoint spreads. Thus, storm activity will likely produce very little precipitation, which will enhance the threat for fire starts.