Marine Weather Net

Florence to Cape Blanco OR from 10 to 60 NM Marine Forecast


TONIGHT

NE
WINDS
5 - 15
KNOTS

MON

S
WINDS
5 - 15
KNOTS

MON NIGHT

SW
WINDS
10 - 20
KNOTS

TUE

NW
WINDS
5 KNOTS

The Marine Weather Forecast In Detail:
PZZ370 Forecast Issued: 828 PM PST Sun Dec 05 2021

SMALL CRAFT ADVISORY IN EFFECT FROM MONDAY MORNING THROUGH MONDAY EVENING
Tonight...Ne Wind 5 To 15 Kt...Veering To S Late Tonight. Wind Waves 3 Ft Late In The Evening...Becoming 2 Ft Or Less. Nw Swell 5 To 6 Ft At 10 Seconds. Rain.
Mon...S Wind 5 To 15 Kt...Rising To 10 To 20 Kt In The Late Morning And Afternoon. Wind Waves 3 To 5 Ft. Mixed Swell Nw 3 To 4 Ft At 10 Seconds And W 2 Ft At 13 Seconds. Rain.
Mon Night...Sw Wind 10 To 20 Kt...Easing To 5 To 10 Kt After Midnight, Then...Veering To W Early In The Morning. Wind Waves 3 To 4 Ft In The Evening...Becoming 2 Ft Or Less. Swell W 5 Ft At 11 Seconds. Rain Likely Through The Night.
Tue...Nw Wind 5 Kt...Backing To W In The Afternoon. Wind Waves 2 Ft Or Less. Swell W 4 To 5 Ft. Chance Of Showers Through The Day.
Tue Night...W Wind 10 To 15 Kt. Wind Waves 2 Ft Or Less. Swell W 4 To 5 Ft. Rain Likely.
Wed...W Wind 10 To 15 Kt...Veering To Nw In The Afternoon. Wind Waves 3 To 4 Ft. Swell W 5 To 7 Ft. Rain.
Wed Night...Nw Wind 10 To 15 Kt. Wind Waves 3 To 4 Ft. Swell W 8 To 9 Ft. Rain Likely.
Thu...Nw Wind 15 To 20 Kt. Wind Waves 4 To 5 Ft. Nw Swell 12 To 14 Ft.
Fri...Nw Wind 20 Kt...Easing To 10 Kt In The Afternoon, Then... Backing To W In The Evening...Backing To S After Midnight. Wind Waves 5 Ft...Becoming 2 Ft Or Less. Swell Nw 11 To 12 Ft.
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Area Forecast Discussion
National Weather Service Medford OR
834pm PST Sunday Dec 5 2021

06/00Z NAM in. 06/00Z GFS in through 84HR.

The hemispheric pattern shows a progressive wave number of five around the globe, but cold air will remain to the north of the Pacific Northwest, at least initially.

A pattern change is underway at this time, as an upper level ridge is now breaking down over the Medford forecast area. A short wave riding over the ridge will move onshore Monday evening. This will push the first of a series of fronts onshore Monday. The short wave will dive to the south while remaining offshore, so the front will weaken as it loses upper level support. Surface short waves will form on the frontal boundary, delaying it's progress. What's left of the front will move inland Monday night. Most of the short wave energy, and the associated precipitation, will affect central and southern California.

Snow levels will be between 6000 and 7000 feet, which will limit impacts. Precipitation will be focused along and west of the Cascades and along the west facing slopes of the foothills Monday. East of the Cascades, winds will be gusty over the ridges (remaining below advisory criteria) with some precipitation. Showers will continue.nue into Monday night, then gradually diminish during the overnight hours.

There will be a relative break in the action Tuesday as a short wave ridge moves through, but some showers will persist along the north coast and in the Umpqua Basin. The next short wave will push a weak front onshore Tuesday night. Yet another short wave will reinforce the front Wednesday into Wednesday night, and post- frontal showers will continue.nue through Wednesday night.

Precipitation amounts will be on the light side. Most of it will fall along and west of the Cascades. Fast west to northwest flow aloft usually results in little or no precipitation east of the Cascades. However the east side will be windy, especially Wednesday afternoon and evening. The reinforcing trough will bring colder air into the area, and snow levels will fall to between 2000 and 2500 feet late Wednesday night. However, the heaviest precipitation will be done by then. The impact on roadways, even at pass levels, will be limited, but not non-existent.

Extended discussion from the Sunday afternoon AFD...Thursday 09 Dec through Sunday night 12/13 Dec 2021. The blended model solution was utilized in the long term. There is high confidence that our area will be in the midst of an active pattern through the long term. Model differences in the strength, timing, and position of disturbances are moderate during the Thursday through Friday period then more substantial for the upcoming weekend.

The probability of precipitation and temperature/snow level forecast are arguably the most potentially impactful fields in the long term. The NBM solution looks right on track, in harmony with the average of ECMWF (European Centre for Medium-Range Weather Forecasts) ensemble and GEFS members, Thursday through Friday. For the weekend, there is a a likelihood of precipitation in much of southwest Oregon by Saturday night. But, during Saturday in southwest Oregon and throughout the weekend in both south central Oregon and northern California, the probability of precipitation is likely to end up either decidedly higher or lower than the currently mentioned slight chance to chance. As such, the highest precipitation rates/amounts, strongest winds, and highest impact conditions within the 7-day period may occur next weekend.

But first, on Thursday morning, a chance of snow showers from an exiting system will linger over the Warner Mountains of Modoc and southern Lake counties while the next cold front is expected to be moving southeast to the northern Oregon coast. There is good model agreement that later in the day there will be a higher probability of precipitation spreading into southwest Oregon, northern Klamath County and far western Siskiyou County. As much as a couple inches of snow is forecast above 2000 feet, mainly in eastern Douglas County near Diamond Lake and northward...including the Willamette Pass.

The snow level may dip just a hair below 2000 feet, forecast to be around 1800 feet, during Thursday night with a higher potential for a stronger shortwave and surface trough to produce western Oregon focused precipitation. 3 to 6 inches of snow is forecast for the southern Oregon Cascades, mainly in the Diamond Lake/Crater Lake area. But also, 1 to 2 inches for the Crescent, Prospect, Sexton Summit, Siskiyou Summit, Kalmiopsis Wilderness, and far western Siskiyou County mountain areas. With the recent near normal to above normal temperatures for most of the aforementioned areas, impacts/accumulation of snow on roadways may be limited.

There is also good agreement on a weaker shortwave trough bringing at least a chance of light showers to at least the coast and Douglas County on Friday...with a slight chance for the remainder of southwest Oregon. Brief shortwave ridging is expected to follow Friday night with the next cold front bringing a chance of light rain at the coast by the end of the Friday night.

During the weekend, in the big picture, ridging is expected from southern California across the desert southwest and northward along the Rockies. Meantime, a broad, powerful, cold trough is expected to slowly weaken while positioned from the Gulf of Alaska to far offshore of northern California. The main uncertainty regards the extent to which the ridge will block the eastward progress of what is likely to be a potent cold front. A range of solutions either: keeps the front offshore, keeps the front offshore Saturday before it marches inland early next week, allows it to reach our coast before temporarily retrograding to offshore, or has the front make very slow to slow progress across our area. The analysis of the Day 6 and Day 7 cluster of ensemble members shows a slight bias toward stronger ridging, away from the wet operational GFS and ECMWF solutions, for Saturday. This is also climatologically favored, and would usher in warmer air, a rise in snow levels on Saturday. Then, a higher potential for long overdue truly stormy weather next Sunday in which at least our major passes would likely see snow. -DW

Marine
Updated 800pm PST Sunday, December 5, 2021...Moderate north to northeast winds and choppy seas will persist through early tonight south of Cape Blanco. A weak warm front will move across the waters on Monday with gusty south winds and steep seas affecting the waters north of Cape Blanco. Seas will lower Monday night and Tuesday. Then, seas are forecast to build late in the week as more storms develop offshore. More specifically, latest data suggests seas will become high Wednesday and Wednesday night as a long period swell at 14 to 15 seconds builds into the area. Seas subsequently build to around 13 to 15 ft at 13 seconds Thursday into early Friday. A front may arrive Saturday with strong south winds and a bring continued elevated seas. -CC/Smith

NOAA Medford OR Office: Watches - Warnings - Advisories
OR...Air Stagnation Advisory until 4am PST Monday for ORZ024-026.

CA...None.

Pacific Coastal Waters... Small Craft Advisory until 1am PST Monday for PZZ356-376. Small Craft Advisory from 10am to 10pm PST Monday for PZZ350-370.