Marine Weather and Tide Forecast for Four Corners, OR

SHORT TERM
Now through Friday Night...There remains minimal overall change in the weather pattern that has been impacting the region over the past 48 hours. The two significant synoptic forces that will maintain this pattern are a broad upper-level ridge to our south-southeast and a broad trough over the Gulf of Alaska. Between these two systems is an Atmospheric River (AR)
which remains aimed at British Columbia. While the upper-level ridge almost certainly facilitates spring like conditions over the area, our focus remains on the an AR, which continues to take aim at the western Olympic Peninsula and Vancouver Island.
The push and pull of both the aforementioned trough and ridge will result in the AR "wobbling" and these "wobbles" could bring rounds of precipitation into the northern areas as well as to the coast through at least Friday evening. In general, what you have experienced over the past 48 hours or so, is likely what you will continue to observe through the remainder of the week.
IE: Most areas will see warm, spring like conditions with little to no precipitation. However, Pacific and Wahkiakum Counties as well as the north Oregon coast will continue to experience a cooler and moister patter with additional rain totals ranging between 0.50-2.75 inches through 10PM Friday, with the highest totals in northern Pacific County.

As for the other areas within in our CWA, conditions remain dry through Friday, particularly south of the Portland/Vancouver Metro area. Broad, southwesterly flow aloft and 850mb temperatures of 8 to 11 degrees C, means that daytime high temperatures are forecasted to be in the mid 60s to low 70s across the lowlands.
Warmest daytime highs are expected south of Salem, OR with Eugene, OR likely warming into the low 70s today and tomorrow.
However, if skies remain clear, then daytime highs across the CWA could easily be warmer than what is forecasted at this time.
Twice daily upper air soundings along with observations from various remote sensors spread across our CWA, are also supporting a very dry airmass. This is resulting in very low relative humidities and poor overnight recoveries, especially for locations at higher elevations within the Cascades, Cascades Foothills and the Coast Range. /42

LONG TERM
Saturday through Wednesday...Looking forward into the weekend the large scale pattern finally shows signs of progressing. However, exactly what that will look like is still in question. Uncertainty remains high, but the current consensus is for an upper-level trough and associated cold front will be able to further displace the southerly ridge mentioned in the short term discussion. This scenario will enable cooler 850 mb temperatures of 0 to 3 degrees C to infiltrate into the Pacific NW by Saturday and while a frontal system will normally bring precipitation with it, that might be a challenge as the strength of the system remains in question, in addition to the already entrenched dry airmass could easily scour out the majority of any moisture. As we move into the start of next week, uncertainty in the forecast remains high.
The majority of models and their ensembles show a broad upper level trough developing within the Gulf of Alaska and said trough could swing southward into the Pac NW or remain somewhat stationary, yet still send slugs of cool and moist air into the region. Overall, for the start of next week through the middle of next week, conditions are most likely to cool down with some precipitation as the majority of models have a trough impacting the Pac NW by the start of next week. /42

AVIATION
Radar imagery as of late Wednesday morning depicts a band of light to moderate rain over the north Oregon and south Washington coast as an atmospheric river is squeezed between an upper level ridge to the south and a broad upper level trough over the Gulf of Alaska. Rain is expected to continue throughout the TAF period at KAST, while conditions remain drier further south.
High pressure will also keep marine stratus along the coast and thus IFR/MVFR conditions. Occasional drops to 3-5 SM expected around AST during periods of heavier rain or mist. Meanwhile, Willamette Valley terminals remain VFR with high clouds throughout the TAF period as these locations stay under the influence of the upper level ridge.
Winds generally southerly to southwesterly and under 10 kt, except for occasional gusts up to 20 kt along the coast.

KPDX AND APPROACHES...Predominately VFR conditions with high clouds through the TAF period. Southerly to southeasterly winds under 10 kt. -10

MARINE
Southerly winds across all waters expected through the middle of the week. Occasional wind gusts up to 25 kt will be possible for zones PZZ251, PZZ271 and the Columbia River Bar through Thursday. Seas of 7 to 10 feet at 10 to 13 seconds as winds increase and a southwesterly to westerly swell moves into the waters. Chances for Small Craft conditions remain low for the weak system that moves through on Thursday. /42-19

PQR WATCHES/WARNINGS/ADVISORIES

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