NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION. Privacy and Cookie policy

PZZ135 Puget Sound And Hood Canal- 215 Pm Pst Thu Dec 7 2023
Tonight..SW wind to 10 kt. Wind waves 1 ft or less. A chance of rain.
Fri..SW wind to 10 kt in the morning becoming light. Wind waves 1 ft or less in the morning becoming less than 1 ft. A chance of rain in the morning.
Fri night..SE wind to 10 kt. Wind waves 1 ft or less.
Sat..SE wind 5 to 15 kt becoming S 10 to 20 kt in the afternoon. Wind waves 1 to 3 ft.
Sat night..S wind 15 to 25 kt. Wind waves 2 to 4 ft.
Sun..S wind 10 to 20 kt becoming 5 to 15 kt in the afternoon. Wind waves 1 to 3 ft.
Sun night..SW wind to 10 kt. Wind waves 1 ft or less.
Mon..Light wind. Wind waves less than 1 ft.
Tue..Light wind. Wind waves less than 1 ft.

PZZ100 215 Pm Pst Thu Dec 7 2023
Synopsis for the northern and central washington coastal and inland waters..Onshore flow prevails tonight with highest wind and waves through the strait of juan de fuca. The flow will turn southerly then increase Friday night into Saturday as a strong pacific frontal system forms over the ne pacific. This system may bring gales to the waters. Winds will ease on Sunday. The flow weakens and turns offshore early next week with high pressure.

FXUS66 KPDT 080433 AFDPDT

Area Forecast Discussion National Weather Service Pendleton OR 833 PM PST Thu Dec 7 2023

UPDATE
Most of the lower elevation rain showers have dissipated, however there continues to be snow showers over the Cascades and the northern Blue Mountains. There will be low end advisory snow amounts, mainly near the crests of the Cascades and the northern Blues overnight and Friday morning. The NBM 4.1 is showing a 40-60% probability of 6 inches or more of snow in the northern Blue Mountains. In the OR Cascades, the probabilities for 6 inches or more of snow are higher (80 to near 100%), but only a 40-60% chance of 8 inches or more. In the WA Cascades, these probabilities are about 20-30% lower than in the OR Cascades.
Winter Weather Advisories are in effect for these locations overnight and Friday morning until 10 AM PST. However, advisory amounts of snow will be mainly over the crest, with a sharp downward gradient of snow amounts with greater distances away from the crests of these mountain ranges.

The snow showers are being caused by an upper trough that is currently slowly moving across the region. By late Friday morning, the main part of the upper trough will be east of the forecast area, and a drier northwest flow aloft will develop on the back side. This will cause a continuation of some upslope mountain showers, but with light accumulations.

Friday night and Saturday an upper ridge with drier conditions will move across the PacNW. This will be followed by another weather system late Saturday night into Sunday. Both the deterministic models and ensembles are in very good agreement with the evolution of these weather pattern changes through the weekend. This next system on Saturday will have characteristics of an Atmospheric River (AR), but it will be much weaker than the most recent AR. It will also concentrate the moisture over northern and western portions of the CWA again. Only the WA Cascades are showing about an 80-95% probability of 6 inches or more of snow, and a 60-70% probability of 8 inches or more snow.
The OR Cascades and the northern Blues are showing much less probabilities for advisory amounts of snow.

Temperatures will be cooler on Friday, with highs in the 40s, with 20s and 30s in the mountains. High temperatures will be similar on Saturday, and then a couple degrees warmer on Sunday and Monday.

It will be breezy to windy in areas of the forecast area tonight, especially in open terrain with little vegetation. Winds will then become light by Friday evening in all areas. Southerly winds will then increase again by Saturday afternoon in the Grande Ronde Valley and to the lee of the Wallowa Mountains ahead of the next weather system. 88

AVIATION
06Z TAFs...A weather system and upper trough will continue to move across the region overnight and then it will move to the east on Friday. The main effects from this weather system will be breezy to windy conditions at mainly KPDT, KALW, and KPSC tonight. Winds will then become light in all areas by Friday evening. Conditions will otherwise be VFR through the next 24 hours, since shower activity has decreased or ended at all terminals, with CIGs above MVFR heights. 88

PREV DISCUSSION
/issued 233 PM PST Thu Dec 7 2023/

SHORT TERM
Tonight through Saturday
The upper level trough moving into the Pacific Northwest today will pass across the forecast area overnight then exit to the east on Friday. Will see some showers across the forecast area this afternoon and overnight mainly over the mountains then decreasing and ending on Friday. Some marginal to very low end advisory level snow accumulations are expected along the crest of the Cascades and over the northern Blue Mountains through Friday morning where snow advisories are in effect. A temporary ridge of high pressure will pass over the region late Friday through early Saturday before the next weather system arrives Saturday afternoon and overnight. This will arrive as a warm front followed by a weak cold frontal passage on Sunday night into Monday. Initially snow levels on Saturday will be low around 1000 to 2000 feet then rise overnight to 3000 to 6000 feet. This will turn precipitation over to rain by early Sunday everywhere except far eastern areas near Idaho where snow levels remain near 3000 feet. 24 hour NBM snow probabilities are indicating only a 40-60% chance of 4 to 6 inches of no at Snoqualmie pass between 18Z Sat to 18Z Sunday indicating a marginal advisory event at this time. No other mountainous zone is showing any probabilities over 10%. Will also see some increasing south to southeast winds over the weekend associated with the warm front. This could lead to advisory level winds in the southern Grande Ronde Valley area Saturday into Sunday.

LONG TERM
Sunday through Thursday
The period will start out active over the weekend as a trough slides across the Pacific Northwest Sunday morning, lingering through Sunday night/Monday morning. The main weather with the weekend system will be mountain snow and southeasterly winds through the Grande Ronde Valley. 12Z EPS EFI values for QPF, valid 00Z Sunday - 00Z Monday, are 0.6-0.9 for the Blue Mountain foothills, northern Blues, and 0.5-0.7 all of the lower Columbia Basin/Gorge and adjoining lower elevations of Washington. 12Z EPS EFI values for snow, valid 00Z Sunday - 00Z Monday, are 0.6-0.9 for the northern Blue Mountains and 0.5-0.7 for the northwest portion of our forecast area including Yakima and Kittitas counties. These values highlight reasonably good ensemble agreement in a climatologically unusual snowfall event for the mountains with lower agreement in QPF and snow for the Washington Basin/valleys.

Tuesday through Wednesday, ensembles are in excellent agreement that upper-level ridging will build over the Pacific Northwest with mostly dry conditions.

12Z EPS EFI values for wind, valid 00Z Wednesday - 00Z Thursday, highlight the Grande Ronde Valley for a wind event. While values are not high (0.5-0.6), this is the windy season for the Grande Ronde so it takes excellent ensemble agreement in a very strong forecast wind event for the EPS forecast distribution to exceed the climatological distribution in a noticeable way such that EFI values approach 0.9- 1. While ensemble clusters do show some uncertainty in the details of the longwave pattern for Wednesday, agreement in the overall pattern (upper-level ridging over the Rockies and northern Plains with a closed low or open wave for the Southwest US) is very good so confidence in some form of a wind event is high. Regarding the aforementioned wind for the Grande Ronde Valley, NBM 4.2 probabilities indicate a 25-45% chance of exceeding 39 mph gusts Wednesday.

Model uncertainty grows by Thursday as ensemble clusters show 57% of members form some flavor of a closed low over the Pacific Northwest while 35% keep offshore troughing with southwest flow aloft over the Pacific Northwest and ridging over the Rockies and northern Plains, and the last 8% show a ridge centered over western OR/WA. Plunkett/86

PRELIMINARY POINT TEMPS/POPS
PDT 35 42 27 44 / 30 20 0 10 ALW 36 43 28 43 / 50 30 0 10 PSC 37 47 30 41 / 10 10 0 20 YKM 29 46 27 38 / 10 0 0 40 HRI 37 47 28 43 / 20 10 0 20 ELN 30 41 25 37 / 10 0 0 50 RDM 26 40 21 42 / 30 20 0 10 LGD 31 39 25 38 / 90 50 0 10 GCD 28 39 20 41 / 60 40 0 10 DLS 38 48 31 42 / 40 10 0 40

PDT WATCHES/WARNINGS/ADVISORIES
OR...Winter Weather Advisory until 10 AM PST Friday for ORZ502-509.

WA...Winter Weather Advisory until 10 AM PST Friday for WAZ030-522.

toggle option: (graph/table)

Des Moines
Click for Map
Thu -- 12:54 AM PST     7.86 feet High Tide
Thu -- 01:49 AM PST     Moonrise
Thu -- 06:03 AM PST     4.91 feet Low Tide
Thu -- 07:42 AM PST     Sunrise
Thu -- 12:34 PM PST     11.50 feet High Tide
Thu -- 01:36 PM PST     Moonset
Thu -- 04:18 PM PST     Sunset
Thu -- 07:45 PM PST     2.63 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Des Moines, Washington, Tide feet

Duwamish Waterway
Click for Map
Thu -- 12:50 AM PST     7.40 feet High Tide
Thu -- 01:49 AM PST     Moonrise
Thu -- 06:06 AM PST     4.61 feet Low Tide
Thu -- 07:43 AM PST     Sunrise
Thu -- 12:30 PM PST     10.83 feet High Tide
Thu -- 01:36 PM PST     Moonset
Thu -- 04:18 PM PST     Sunset
Thu -- 07:48 PM PST     2.47 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Duwamish Waterway, Washington, Tide feet

Full Color Weather Map

Link to Loop


Other links: GEOS-West     Contential US     Full GOES-East

Seattle/Tacoma, WA,