Marine Weather and Tide Forecast for Cedar Mill, OR

SHORT TERM
Now through Sunday Night...Water vapor satellite imagery this afternoon shows the upper level ridge shifting east over the Canadian Rockies while southwest flow increases aloft over the Pacific NW. Warm and dry weather continues through this evening while offshore surface pressure gradients weaken and the flow turns back onshore.

Winds become more southerly ahead of a weak cold front that will approach the coast later this evening. As an upper level shortwave trough lifts across northwestern WA early Saturday, chances for light rain will increase along the coast and then spread inland through Sat morning. Mean QPF values range from a trace to 0.10 inch, generally north of Newport at the coast and from Eugene northward along the I-5 corridor. Conditions expected to dry out by the afternoon with northerly winds behind the front. Highs will be closer to normal, topping out in the mid to upper 60s across the interior valleys. Will need to keep an eye on Saturday night as clouds clear and temperatures drop into the 30s. Outside of the Cascades, the coolest temperatures are expected in the Upper Hood River Valley.

Dry weather is expected on Sunday as a relatively flat shortwave ridge passes over the region. Seasonable temperatures continue with highs peaking in the mid-60s for most interior lowlands and mid-50s to lower 60s along the coast. Sunday night into Monday morning will bring another chance for frost in the Upper Hood River Valley and the southern Willamette Valley as lows could drop into the mid to upper 30s. /DH

LONG TERM
Monday through Thursday Night...There is generally good agreement among models and their ensembles that a rather robust low pressure system will move across the northeastern Pacific toward the Oregon coast early Monday, but remain far enough offshore before dropping south to bring any meaningful impacts to the area. In fact, chances for even light rain have generally decreases to around 25% or less, mainly near the coast and Coast Range south of Astoria. The upper level trough over the Pacific is expected to split with the main low pressure area moving south toward the central California coast on Tuesday. Ensemble clusters remain in decent agreement for the upper level low to persist near the California coast on Wednesday, while shortwave ridging nudges into the Pacific NW. There is high confidence for dry conditions to persist across the area Tuesday through Wednesday, with temperatures warming back into the mid to upper 60s. More uncertainly returns later next week as another upper level trough begins to drop out of the Gulf of Alaska. Chances for rain increase on Thursday, though currently remain less than 40%. /DH

AVIATION
Through 00Z Sunday...Currently, VFR conditions inland and a mix of VFR to LIFR along the coast as marine stratus builds into the coastal terminals. Expect VFR conditions at inland terminals to continue through 12Z Sat while some coastal terminals will likely remain in IFR/LIFR conditions through around 18Z Sat. The one exception is that an approaching front tonight into tomorrow morning may help clear this low stratus at a few terminals. For example, while KONP may stay under IFR/LIFR conditions through around 18Z Sat, KAST may improve to MVFR/VFR conditions by 11Z Sat as the front approaches KAST and improves mixing. This approaching front will also increase high cloud coverage, chances of rain, and chances of MVFR conditions at inland terminals. There is limited confidence for rain at various terminals, with the highest confidence along the north OR/south WA coast (KAST, KTMK). Between 12-16Z Sat, there is a 40-60% chance of MVFR CIGs and rain at inland terminals.

Gusty east winds through the western Columbia Gorge continues to weaken late this afternoon as the offshore pressure gradient eases. Elsewhere, light winds inland and west to northwest winds along the coast will turn out of the south to southwest at around 5 kt ahead of the frontal passage.

KPDX AND APPROACHES...VFR conditions with increasing high cloud cover through this evening and into tonight. A passing front will bring chances for MVFR cigs and light rain from 12-15Z Sat.
Light east winds this afternoon will turn southerly ahead of the frontal passage tonight. ~12

MARINE
Winds back today into tonight ahead of an approaching cold front which will traverse the waters late tonight, before veering out of the northwest Saturday morning behind the frontal passage. Seas of 5-7 ft at around 12 seconds otherwise continue through Saturday. The mid-period northwest swell will then build over the weekend, with seas rising to 8-10 ft. Chances for seas to exceed 10 ft reach 10-20% beyond 30 NM north of Cape Falcon.
This swell will also pose a moderate risk for sneaker waves along the coast while overall seas remain relatively benign; caution should be used by those in or near the water along coastal beaches through this weekend.

As another weather system looks to track southward well offshore of the Oregon and Washington coasts early next week, and may bring a period of steeper seas Monday into Tuesday although there remains uncertainty in the timing and potential peak wave height.
The latest forecast depicts the westerly swell reaching 11-12 ft at 12-14 seconds Monday afternoon and evening before easing below 10 ft by Tuesday morning, with a 10-20% chance significant wave heights reach 15 ft or higher beyond 20 NM. -36

PQR WATCHES/WARNINGS/ADVISORIES

OR...None.
WA...None.
PZ...None.