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

PZZ110 Grays Harbor Bar- 728 Pm Pst Wed Nov 29 2023
combined seas 3 to 5 feet. Bar conditions light becoming moderate Thursday night. Maximum ebb currents will occur at 615 am Thursday, 615 pm Thursday, and 700 am Friday. The Thursday afternoon ebb will be strong.

PZZ100 728 Pm Pst Wed Nov 29 2023
Synopsis for the northern and central washington coastal and inland waters..A weak surface ridge over the waters will give way to a frontal system arriving Thursday morning. A more vigorous frontal system will follow on Friday. This will begin an active period of weather with a series of potent frontal systems reaching the waters in rapid succession through early next week.

FXUS66 KPQR 292347 AFDPQR

Area Forecast Discussion National Weather Service Portland OR 346 PM PST Wed Nov 29 2023

SYNOPSIS
A big pattern change is on the way as a pair of atmospheric rivers brings heavy Cascade snow and valley rain to the area Thursday through the upcoming weekend. There is the potential for a third atmospheric river early next week, however uncertainty is very high with this system.

SHORT TERM
THROUGH THURSDAY NIGHT...Satellite and surface weather observations across northwest OR and southwest WA depicted overcast skies and calm winds (away from the mouth of the Columbia Gorge) as of 2 PM PST Wednesday. Model guidance is not handling the current extent of cloud cover well and manual adjustments to the sky cover forecast were necessary to better reflect observations. Given the calm winds and low mixing heights in place, air quality has degraded into the moderate category to unhealthy for sensitive groups category across portions of the central and southern Willamette Valley.
Therefore, an Air Quality Advisory remains in effect for these areas, including Salem and Eugene-Springfield. This Air Quality Advisory remains in effect until 10 AM Thursday and will likely not need an extension as transport winds/low-level mixing will begin to rapidly increase shortly thereafter as a Pacific frontal system moves inland.
This will help improve air quality.

The latest suite of hi-res model guidance is in good agreement regarding the onset of rain with this system, suggesting light to moderate rain will begin at the coast and over the coastal mountains Thursday morning before pushing into the interior lowlands of southwest WA/northwest OR during the late morning and early afternoon hours. Rain should reach the Cascade foothills around Noon. For the mid and upper slopes of the Cascades (elevations above 3000 ft), precipitation will fall in the form of snow as snow levels look to hover around 3000 ft before falling to around 2500 ft Thursday night.
As such, accumulating snow will occur at pass level and will impact travel conditions along portions of US26, ORE22, US20, and ORE126. In fact, anywhere from 4 to 8 inches of snow is expected for elevations above 3000 ft from Thursday through Thursday night. Travel conditions over the passes will degrade even more thereafter as a relatively stronger system brings heavy Cascade snow Friday into the weekend.
This system is discussed below in the long term discussion and the hydrology discussion. -TK


LONG TERM
FRIDAY THROUGH TUESDAY NIGHT...The long term discussion is highlighted by a very wet/active weather pattern as a series of at least two atmospheric rivers impacts the region. The first atmospheric river, albeit a weak one with IVT values around 250-300 kg/ms, is set to arrive early Friday morning and continue through Friday night. Models and their ensembles are showing a considerable degree of model spread in regards to 24-hr QPF amounts ending at 4 AM Saturday. The NBM 10th-90th percentile highlights this model spread well as the 10th percentile is showing rain around around 0.35-0.6 inches along the I5 corridor from Kelso/Longview to Vancouver/Portland to Salem to Eugene. On the contrary, amounts NBM 10th percentile QPF amounts are closer to 0.75" along the coast and 1-1.5" in the Coast Range and Cascades. Meanwhile, the NBM 90th percentile is much higher with QPF amounts of 1.5-2.0 inches along the I5 corridor, 2-3" along the coast, and 3-5" over the mountains.
The official QPF forecast reflects amounts closer to the NBM 50th percentile, which seems to represent a reasonable middle-ground solution at this time. Unless the wettest model solutions verify, hydro impacts should be minimal Friday/Friday night as river levels leading into this event will be relatively low. The biggest concern will be heavy snow in the Cascades as models continue to suggest a solid 10 to 20 inches of snow will fall Friday through Saturday afternoon for elevations above 3000 feet (except up to 32 inches above 5000 feet). This will make travel extremely difficult for those attempting to travel over the Cascade passes. Winds will also gust up to 55 mph at times over the high Cascades. This will reduce visibilities even more as blowing snow combines with falling snow.

Conditions will only worsen Saturday night into Sunday as a moderate atmospheric river pushes into the area immediately behind Friday/Friday night's weak atmospheric river, bringing more heavy snow to the Cascades and heavy rain elsewhere. As such, a Winter Storm Watch remains in effect from late Thursday night through Saturday afternoon for elevations above 3000 feet. Aside from dangerous travel conditions over the Cascade passes, flooding concerns will begin to increase along rivers, creeks, small streams, and in urban areas with poor drainage as river levels will already be elevated leading into the second round of heavy precipitation.
Forecast rain amounts and the potential for flooding are discussed below in Hydrology discussion.

Lastly, there is the potential for a third atmospheric river early next week, however uncertainty with this system is very high. For example, GEFS/EPS IVT values along the south WA/north OR coast range from <250 kg/ms (which wouldn't be considered an atmospheric river at all) all the way up to around 1000 kg/ms (which would be considered a strong atmospheric river). The latest suite of deterministic model guidance also shows solutions all over the place as the GFS/Canadian aim the atmospheric river at Vancouver Island and northwest WA and the EURO aims it at western WA and northwest OR. Given river levels will be elevated leading into this potential event, will need to watch future model guidance closely for increasing confidence as to where the potential third atmospheric river will aim. -TK

HYDROLOGY
With heavy rain in the forecast this weekend into early next week, river levels will be on the rise. Will there be enough rain for flooding to occur? Well, the answer to that is still uncertain due to a considerable degree of model spread regarding QPF amounts for both the weekend system and the potential system early next week. QPF plumes from the EPS/GEFS for various points across southwest WA and northwest OR highlight the model spread well, as does the NBM QPF percentile guidance. For example, the NBM 90th-10th percentile for 48-hr QPF amounts ending at 4am Monday are around 2.5-5.0 inches over the area (highest at the coast and in the mountains). This means the wettest model solutions are producing rain amounts that are up to 5 inches higher than the "driest" model solutions. This is mainly due to uncertainty regarding the location of the axis of heaviest rain, but also due to some uncertainty regarding the intensity of precipitation. With such an extreme degree of model spread, it is very difficult to determine if river flooding will occur in a deterministic sense. To make matters even more difficult, there is the potential for yet another atmospheric river early next week (however uncertainty is even higher for this system and is discussed above in the long term discussion).

Given the high uncertainty involved, it is best to message the chance of river flooding probabilistically using HEFS guidance. While the latest HEFS guidance is showing around a 5% chance mainstem rivers will reach flood stage through early next week, there is at least a 10-20% chance coastal rivers/rivers draining the Coast Range will reach minor or even moderate flood stage. To view current and forecast river stages, as well as HEFS guidance, visit https://water.weather.gov/ahps2/index.php?wfo=pqr

Lastly, minor urban flooding is also possible this weekend, especially in areas with poor drainage. If you have gutters and/or storm drains that still need to be cleared out, now is the time. Any motorists with travel plans this weekend should also allow extra time for their commute as hydroplaning will be a risk. -TK

AVIATION
Widespread upper level clouds continue to spread across the region this afternoon. This is resulting in VFR conditions across the region. However, a pattern change is expected to start around 08Z-10Z Thursday for the coast and around 11Z-15Z for inland locations as the first in a series of fronts starts to cross the region. The first frontal passage is expected to bring a mixture of low-end VFR/high-end MVFR and precipitation through the remainder of the TAF period.

** The new Aviation Weather Center website is live. The new website can be found at aviationweather.gov **

KPDX AND APPROACHES...Predominately VFR through the TAF period.
Weak frontal passage expected around 15Z-17Z which will bring precipitation as well as a mixture of low-end VFR/high-end MVFR through the remainder of the TAF period. /42

MARINE
Wednesday night to Thursday, a cold front will move through the waters, turning winds southerly and resulting in Small Craft conditions developing in all waters by early Thursday morning. Seas at the same time will gradually build towards 8-10 ft by Thursday evening. Friday and continuing into the weekend, a series of systems will move through the waters, resulting in a very active weather pattern through the start of the upcoming week. Winds gusts up to 40 kt will be possible. Therefore, have issues a Gale Watch for all waters starting late Thursday night/early Friday morning. In addition, seas will also build towards 14-17 ft starting Friday through the weekend and into the start of next week as the active weather pattern will persist.
/42

BEACH HAZARDS
There is a high sneaker wave threat Saturday-Tuesday.

A high sneaker wave threat will be present along the OR and WA coast starting this Saturday and continuing through at least next Tuesday. The cause is a series of systems coming from the central Pacific Ocean and moving towards the Pacific NW. Expect wave height to slowly build towards 14-17 ft with a dominant period of 15-19 seconds.

It is important to not focus on the highest wave heights as a representation of peak sneaker wave threat; the period between the waves is almost more important as it represents the energy being carried by the swell. Sneaker waves will drive up further on the beach when compared to waves of similar height. This can potentially catch beachgoers off guard. In addition, waves can easily lift and move large logs on the beach and knock people/pets off of jetties. Therefore, have issued a Beach Hazard Statement along our CWA's entire coast starting very early Saturday morning and going through at least very early Tuesday morning. /42

PQR WATCHES/WARNINGS/ADVISORIES

OR...Winter Weather Advisory from 10 AM Thursday to 4 AM PST Friday for Cascades in Lane County-Northern Oregon Cascades.

Winter Storm Watch from late Thursday night through Saturday afternoon for Cascades in Lane County-Northern Oregon Cascades.

Air Stagnation Advisory until 10 AM PST Thursday for Cascade Foothills in Lane County.

WA...Winter Weather Advisory from 10 AM Thursday to 4 AM PST Friday for South Washington Cascades.

Winter Storm Watch from late Thursday night through Saturday afternoon for South Washington Cascades.

PZ...Gale Watch from late Thursday night through late Friday night for Coastal waters from Cape Shoalwater WA to Florence OR out 60 NM.

Small Craft Advisory from 7 AM Thursday to 4 AM PST Friday for Coastal waters from Cape Shoalwater WA to Florence OR out 10 NM.Waters from Cape Foulweather to Florence OR from 10 to 60 NM.

Small Craft Advisory from 4 AM Thursday to 4 AM PST Friday for Coastal waters from Cape Shoalwater WA to Cape Foulweather OR from 10 to 60 NM.

toggle option: (graph/table)

Willapa City
Click for Map
Wed -- 03:35 AM PST     9.42 feet High Tide
Wed -- 07:35 AM PST     Sunrise
Wed -- 08:18 AM PST     4.16 feet Low Tide
Wed -- 10:26 AM PST     Moonset
Wed -- 02:36 PM PST     11.11 feet High Tide
Wed -- 04:29 PM PST     Sunset
Wed -- 06:09 PM PST     Moonrise
Wed -- 09:03 PM PST     -0.83 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Willapa City, Willapa River, Washington, Tide feet

South Bend, Willapa River, Willapa Bay, Washington, Tide feet

Full Color Weather Map

Link to Loop


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

Portland, OR,