Marine Weather Net

Cascade Head to Florence OR from 10 to 60 NM Marine Forecast


REST OF TODAY

S
WINDS
TO 5
KNOTS

TONIGHT

N
WINDS
TO 5
KNOTS

WED

NE
WINDS
5 KNOTS

WED NIGHT

NW
WINDS
5 KNOTS

The Marine Weather Forecast In Detail:
PZZ275 Forecast Issued: 847 AM PDT Tue Sep 13 2022

DENSE FOG ADVISORY IN EFFECT UNTIL 10 PM PDT THIS EVENING
Rest Of Today...S Wind To 5 Kt. Wind Waves S 1 Ft At 4 Seconds. Nw Swell 3 Ft At 9 Seconds. Widespread Dense Fog In The Morning. Areas Of Dense Fog In The Afternoon.
Tonight...N Wind To 5 Kt. Wind Waves N 1 Ft At 4 Seconds. Nw Swell 3 Ft At 9 Seconds. Areas Of Dense Fog In The Evening. Patchy Dense Fog After Midnight.
Wed...Ne Wind 5 Kt, Backing To Nw To 5 Kt In The Afternoon. Wind Waves Ne 1 Ft At 4 Seconds, Shifting To The Nw At 4 Seconds In The Afternoon. Nw Swell 3 Ft At 9 Seconds. Patchy Dense Fog In The Morning.
Wed Night...Nw Wind 5 Kt, Backing To Se After Midnight. Wind Waves Nw 1 Ft At 4 Seconds, Shifting To The Se At 4 Seconds After Midnight. Nw Swell 3 Ft At 9 Seconds.
Thu...S Wind 5 Kt. Wind Waves S 1 Ft At 4 Seconds. Nw Swell 3 Ft At 10 Seconds.
Thu Night...N Wind 5 To 10 Kt. Wind Waves N 2 Ft At 4 Seconds. Nw Swell 3 Ft At 10 Seconds.
Fri...N Wind 5 To 10 Kt. Wind Waves 2 Ft. Nw Swell 4 Ft.
Sat...Nw Wind 5 To 10 Kt. Wind Waves 2 Ft. Nw Swell 4 Ft.
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Area Forecast Discussion
...UPDATED National Weather Service Portland OR
512am PDT Fri August 14 2026

...Updated public and aviation discussions... Synopsis
Warm and dry conditions expected through next week with persistent onshore flow. Slight chances (10-20%) for thunderstorms or showers over the Cascades this afternoon and Saturday afternoon, with the highest chances along the crest of the Cascades.

Radar and satellite imagery around 2:30-3am early this morning showed thunderstorms popping up in the western Portland Metro Area. Mesoanalysis at the time indicated MUCAPE values around 100-500 J/kg. Given that we had a low-level inversion around 2000- 4000 feet this morning which is maintaining low stratus clouds, a lot of the instability and thunderstorms originated in the mid to upper levels of the atmosphere. This was evident by the METARs shown from KHIO and KSPB which reported thunderstorms with cloud bases around 9000-10000 ft. As of 5am Friday, these thunderstorms have moved into the northern Clark County and Cowlitz Valley areas. These seem to be very isolated thunderstorms, so a slight chance (15%) for thunderstorms were added to the forecast across parts of the Portland/Vancouver Metro, Cowlitz County, and Skamania County through at least 6am this morning. -10

Today through Thursday...Satellite imagery and surface observations as of early Friday morning depicts onshore flow supporting a solid marine layer along the coast with stratus clouds pushing through the gaps of the Coast Range and through the Lower Columbia River into the Cowlitz Valley. By 5-7 AM Friday, expect stratus clouds to make it's way into the rest of the I-5 corridor including the Willamette Valley. After 9-11 AM Friday, clouds across interior valleys should begin clearing out as daytime heating progresses and increases mixing. Meanwhile, there remains uncertainty with how much clearing will occur at the coast. There is about a 50-60% chance at any given hour between 2-7pm for marine stratus breaking out along the north Oregon coast, but lower confidence for clearing along the central Oregon coast.

Expect dry and warm conditions today and through the weekend for the majority of locations as weak ridging builds over the Pacific Northwest and an upper level trough elongates well- offshore over the northeast Pacific Ocean. An exception would be the Cascades, where there is a 10-25% chance for isolated thunderstorms this afternoon and Saturday afternoon. As shortwaves from the broad parent trough offshore brings more southerly flow aloft over the area, will see increasing instability and monsoonal moisture supporting these thunderstorm chances. Any thunderstorms that develop may bring lightning, brief heavy rain, and erratic winds. Otherwise, the general airmass remains too dry to support any widespread precipitation west of the Cascades. Guidance suggests high confidence for near to slightly above average temperatures for mid-August through the weekend, with afternoon highs warming into the mid to upper 80s across interior valleys.

Early next week, cluster analysis of 500 mb heigheights continue to suggest dry and seasonably warm conditions as broad upper level troughing remains well-offshore and an upper level ridge axis over the Rockies tilts into the Pacific Northwest. By mid-week, ensembles diverge into various upper level patterns. A little over half of ensemble members are favoring a trough entering the Pacific Northwest and returning cooler temperatures, while the other half favors warmer conditions due to zonal flow or amplified ridging. Either way, no precipitation is forecast as we maintain a dry summertime airmass. -10

Marine
No significant changes in the overall pattern as high pressure offshore will continue to support northerly winds along with benign conditions across all waters through next week. Winds from the north to northwest with gusts less than 21 kts will continue through at least the weekend, with wind driven seas expected to remain around 3-5 ft. -10/42

NOAA Portland OR Office: Watches - Warnings - Advisories
OR...None. WA...None. PZ...None.