Marine Weather and Tide Forecast for Astoria, OR

SHORT TERM
Now through Thursday...Water vapor satellite imagery shows a low amplitude shortwave trough sliding across the Pacific Northwest. This has resulted in scattered, generally light, showers spreading across western Washington and western Oregon today. As 500mb heights build across the region and surface instability decreases this evening, expect showers to gradually decrease in coverage and intensity. In areas that remain clear like the upper Hood River Valley and areas that gradually clear this evening, there is a 50% chance or more for frost in our coldest locations like Odell and Parkdale. The probability for temperatures dropping into the mid 30s is considerably lower (10%-20% chance) for areas like Hillsboro, Battle Ground and across much of the southern Willamette Valley and Cascade Foothill valleys.

Brief ridging late tonight into early Wednesday will give way to another shortwave trough sliding across the region late Wednesday into early Thursday. This will bring another round of light precipitation to the region. Ensembles suggest the light rain is most likely to arrive Wednesday evening into Wednesday night with some light precipitation chances lingering into Thursday across mainly the higher terrain. Temperatures look to remain near to slightly below average for the date through Thursday.


LONG TERM
Thursday Night through Tuesday...WPC Clusters suggest the region will be under the influence of a lingering shortwave trough Thursday night into Friday. However, only 20-30% of global ensemble members suggest deep enough troughing over the region to keep some light precipitation continuing mainly over the northern half of the CWA and the higher terrain of the Coast Range and Cascades.

Global ensemble membership is generally in agreement that shortwave ridging will build into the Pacific Northwest Saturday into Sunday leading to the area drying out further and temperatures warming to well above average by Sunday. With that said, there is 10-20% of the ensemble guidance that delays shortwave ridging, which keeps Saturday cooler.

Uncertainty in the upper level pattern grows early next week.
The main uncertainty revolves around how long shortwave ridging persists over the region and when the next shortwave trough slides into the Pacific Northwest. The current forecast is very middle of the road, but know there is ~25% chance temperatures in the 80s will persist into early next week and there is a ~25% chance that temperatures drop into the 60s with beneficial wet weather returning to the Pacific Northwest.

AVIATION
Weak high pressure begins to build across the region, maintaining VFR conditions throughout the airspace. Inland terminals will see VFR conditions persist through the TAF period, along with northerly to northwesterly winds under 8 kt. Coastal terminals may experience MVFR CIGs before 06Z Wednesday, but expect VFR for the rest of the TAF period. Between 20Z Wednesday and 03Z Thursday, expect gusty northwesterly winds around 10-15 kt with gusts up to 25 kt for coastal terminals.

PDX AND APPROACHES...Predominantly VFR conditions through the TAF period with west to northwest winds under 8 kt.
~Hall

MARINE
A benign onshore flow regime will maintain scattered showers and light to moderate westerly breezes over the coastal waters through tonight. Small Craft Advisories remain in effect through this evening as a mid period period westerly swell keeps seas at or above 10 ft. Seas will subside overnight to 6 to 7 ft by Wednesday morning. Expect relatively calm conditions for the remainder of the week as high pressure yields northerly winds over waters for Wednesday and Thursday, with gusts potentially up to 25 kt later Wednesday afternoon. Onshore flow returns Friday into the weekend. Seas remain in the 5 to 7 ft range through mid week, subsiding below 5 ft by Friday. DH/CB

PQR WATCHES/WARNINGS/ADVISORIES

OR...Frost Advisory from midnight tonight to 8 AM PDT Wednesday for ORZ121.

WA...None.
PZ...Small Craft Advisory until 2 AM PDT Wednesday for PZZ210-251>253- 271>273.