Cascade Head to Florence, OR out 10 NM Marine Forecast
|Today...S Wind 25 To 30 Kt With Gusts To 40 Kt, Easing To 20 To 25 Kt With Gusts To 35 Kt. Combined Seas 17 Ft With A Dominant Period Of 16 Seconds. Rain Early In The Morning.|
|Tonight...S Wind 20 To 25 Kt, Becoming Sw 10 To 15 Kt After Midnight. Wind Waves Sw 3 Ft At 6 Seconds. W Swell 12 Ft At 14 Seconds. Chance Of Rain In The Evening.|
|Sat...Sw Wind 10 To 15 Kt With Gusts To 20 Kt, Becoming S 20 To 25 Kt With Gusts To 30 Kt In The Afternoon. Wind Waves S 5 Ft At 5 Seconds. W Swell 11 Ft At 12 Seconds. Chance Of Showers In The Afternoon.|
|Sat Night...S Wind 20 To 25 Kt With Gusts To 30 Kt, Becoming Sw 15 To 20 Kt With Gusts To 25 Kt After Midnight. Wind Waves S 8 Ft At 7 Seconds, Becoming Wind Waves Sw At 6 Seconds After Midnight. W Swell 7 Ft At 12 Seconds. Rain.|
|Sun...Sw Wind 15 To 20 Kt. Wind Waves Sw 3 Ft At 6 Seconds. W Swell 14 Ft At 13 Seconds. Chance Of Showers.|
|Sun Night...S Wind 10 To 15 Kt. Gusts To 20 Kt, Becoming 15 Kt After Midnight. Wind Waves S 2 Ft At 5 Seconds. W Swell 18 Ft At 17 Seconds. Chance Of Showers.|
|Mon...Se Wind 5 To 10 Kt. Wind Waves 2 Ft. W Swell 15 Ft.|
|Tue...N Wind 5 To 10 Kt. Wind Waves 2 Ft. W Swell 9 Ft.|
| Area Forecast Discussion|
National Weather Service Portland OR
347am PST Fri Mar 5 2021
A rather complex system continues to slowly move inland today as the overall system weakens. Another front arrives Sunday, also weakening as it comes onshore. Generally speaking, the coast will receive the bulk of precipitation while the Cascades receives far less. Low pressure slowly slides south while centered well offshore to bring some form of rain and snow for much of next week.
Today through Sunday Night...The upper front, which has stalled a bit further west than was expected 24 hours ago, is starting to move back onshore this morning. The further west position has resulted in rather meager rain amounts as compared to what was expected by previous shifts. As of this forecast package Quantitative Precipitation Forecast storm totals are running about half of the -24 hr forecast. Given this, any flooding concerns there were for the Grays and Nehalem rivers are long gone.
The leading edge of rain will cross over the Willamette Valley close to daybreak which will help break up the patchy fog which has developed under the clearer to start skies from the last several hours. Expect rain to be more on than off today until the back edge of the front crosses this afternoon and for the Cascades, this evening. Will be curious to see how much shadowing influence comes into play from the southerly flow intersecting the Siskiyous and the Umpqua divide to our south. Already diminished Quantitative Precipitation Forecast amounts may still be overdone. Will get a few inches of snow for the Cascades with the Mt St Helens region likely picking up several inches under the more favorable southerly flow, but still staying below advisory criteria. Additionally with this front, will get some breezy to borderline windy conditions at the coast this morning as smaller scale impulses move north along the front. Gusts 35-45 are most likely for the more exposed beached and headlands. Cannot rule out the occasional gust around 50 mph this morning.
Also along the beaches, incoming westerly and longer period swells will increase the chance of sneaker waves today. Additionally, very small tsunami waves have begun to arrive at the coast early this morning. Although they will have some influence, the primary sneaker wave threat will be from distant storms and not necessarily from the earthquakes off the northern New Zealand.
Temperatures over the next few days will stay a few degrees below normal. Saturday will remain showery under a modestly unstable air mass. May get some small hail embedded in the showers. Showers taper off near sunset Saturday evening and then another front will cross the region late Saturday night and early Sunday morning. This front will also likely end up weaker and splitting to result in what may be perceived more as showers in the morning. The front, or what's left of it, does move east rather quickly leaving Sunday afternoon more convective. Sunday's showers may have a bit more strength to them as the colder air mass from the broader upper low does move overhead. Thunderstorm chances are low and below a mentionable 15%, however, they are not completely zero. Should surface Ts run a couple degrees higher than expected, then a sub 15% thunder threat might bump up closer to 25-35%. /JBonk
Monday through Thursday...Another large upper low will work southeastward from the Bering Sea over the weekend to take up residence between 130 and 140 W off the PacNW coast. This system will then further drop south and then southeast during the several day period of the long-term forecast. As it does so, there will be opportunities for short-waves to rotate around the base of the upper low and bring rain chances every day through Tuesday. Wednesday and Thursday have the best chances for staying dry albeit with temperatures remaining somewhat below normal. As of now, do not expect any significant snowfall for the Cascades, but at least what does fall will likely remain snow, especially across the passes and higher. /JBonk
Buoy observations early Friday morning showed significant wave heigheights around 20 ft across the outer waters, and around 15-16 ft over the inner waters. Combined seas were resulting from a combination of a fresh southerly swell and a long period westerly swell. In addition, a strong cold front was located over the inner waters, which should begin to push inland just before sunrise. This front has brought gusty southerly winds, with buoy observations continuing to show gusts in the 40-45 kt range. By late morning, winds should fall into the 25-34 kt range while combined seas begin to decline into the mid teens. Therefore, it is likely that the Gale Warning will be replaced by a Small Craft Advisory by late this morning. That said, a few gusts to 35 kt cannot be ruled out late this afternoon to the north of Tillamook Head beyond 30 nautical miles.
Expect winds to decrease significantly tonight, falling below 20 kt by late tonight. Despite the weakening winds, seas look to stay elevated in the low to mid teens. It is not until Saturday afternoon that seas should fall to around 10-11 ft. Southerly winds increase again Saturday evening as the next frontal system moves over the waters. At this time, a brief period of gusts between 30-35 kt appear likely with the front.
Westerly swell begins to increase again on Sunday, with guidance suggesting a peak around 18-21 ft by the late afternoon. With a dominant period around 16-17 seconds, this will bring a high sneaker wave threat to local beaches and will also bring the potential for high surf. Expect both seas and winds to improve significantly early next week. -TK
.PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Gale Warning until 9am PST this morning for coastal waters from Cape Shoalwater WA to Florence OR out 60 NM.
Small Craft Advisory until 1pm PST Saturday for Columbia River Bar.