Cascade Head to Florence OR from 10 to 60 NM Marine Forecast
|Rest Of Today...Sw Wind 20 To 25 Kt. Gusts To 35 Kt. Combined Seas 16 Ft With A Dominant Period Of 14 Seconds. Rain.|
|Tonight...Sw Wind 5 To 10 Kt. Wind Waves Sw 2 Ft At 4 Seconds. W Swell 14 Ft At 13 Seconds, Subsiding To 11 Ft At 12 Seconds After Midnight. Chance Of Showers In The Evening.|
|Sat...S Wind 5 To 10 Kt. Gusts To 15 Kt In The Afternoon. Wind Waves Sw 2 Ft At 4 Seconds. W Swell 9 Ft At 11 Seconds.|
|Sat Night...N Wind 5 To 10 Kt. Gusts To 15 Kt In The Evening. Wind Waves N 1 Ft At 4 Seconds. W Swell 7 Ft At 10 Seconds.|
|Sun...Ne Wind 5 To 10 Kt With Gusts To 15 Kt, Rising To 10 To 15 Kt With Gusts To 20 Kt In The Afternoon. Wind Waves Ne 2 Ft At 4 Seconds. W Swell 6 Ft At 10 Seconds.|
|Sun Night...N Wind 20 To 25 Kt With Gusts To 30 Kt. Wind Waves N 4 Ft At 7 Seconds. W Swell 6 Ft At 10 Seconds.|
|Mon...Ne Wind 10 To 15 Kt. Wind Waves 3 Ft. W Swell 9 Ft.|
|Tue...Se Wind 5 To 10 Kt. Wind Waves 2 Ft. W Swell 9 Ft.|
| Area Forecast Discussion|
National Weather Service Portland OR
1107am PDT Fri September 25 2020
Updated: Aviation discussion.
A moist cold front will move east across the region today bringing another round of steady rain. A cool unstable air mass keeps a chance of showers going through Saturday. There will be a change to a drier and warmer weather pattern Sunday into next week as a light offshore flow develops.
Today through Sunday...Satellite and radar imagery shows an impressive front offshore the Washington and Oregon coast early this morning. Satellite derived precipitable water values are higher than previous model forecasts, and shows 1.7 inch values with the cold front. Radar shows widespread rain offshore of the Washington coast. Radar derived MRMS rain rates are around 0.3 inch per hour offshore of Washington and 0.10 inch per hour offshore of NW Oregon. Water Vapor imagery shows an upper level shortwave trough behind the front starting to tilt negatively. Upper level divergence ahead of this trough should provide enough lift to tap into this moisture. The best dynamics for this is across NW Washington, but there may be enough ascent across NW Oregon for a chance of heavy rain across the Willapa Hills this morning and the Cascades this afternoon.
Expect 1 to 2 inches of rain across the Willapa Hills, south Washington Cascades, north Oregon coast range, and the north Oregon Cascades this morning through the late afternoon. Expect 0.75 to 1.25 inch of rain for the Cascades in Lane County, the central Oregon Cascades, and along the coast. The Willamette Valley could see 0.25 to 0.5 inches of rain.
Winds will pick up with the front too, and south gusts will likely peak around 45 mph along the northern beaches briefly Friday morning. Gusts up to 30 mph are possible for the Willamette Valley today, with 40-50 mph for the northern Cascades. Besides rainy and breezy conditions, the beaches also have an enhanced threat for sneaker waves through this evening.
Showers will decrease tonight behind the front, but a moist and unstable airmass will provide the chance for showers, mainly across the higher terrain through Saturday. Rain will end Saturday night and Sunday as an upper level ridge builds over the area. An upper level ridge moves over the area Sunday ending the rain. Clearing, combined with lingering moisture, and light winds will likely lead to fog forming in the interior valleys late Saturday night into Sunday morning. Subsidence from the upper ridge should result in the fog being shallow, and clearing before noon on Sunday. Dry north flow develops Sunday afternoon helping to dry the airmass, and warm the daytime temperatures back to what is normal for this time of the year. ~TJ
No Changes. Previous discussion follows...Sunday night through Thursday..Models in general agreement depicting a sharpening upper ridge over the Pacific Northwest early next week, and then hanging on to the ridge into the latter half of the week. A mild, dry, and for the most part light offshore flow appears likely to persist in the low levels for much of the week, resulting in warmer than normal daytime temperatures and seasonably cool nighttime lows. The easterly offshore flow will likely bring whatever wildfire smoke is available from over the Cascades and just east of the Cascades westward into the region, assuming the fires are still generating smoke.
Another front stemming from the Gulf of Alaska will move across the waters today bring another round of gale force winds and increasing seas. Southerly winds will begin to increase over the northern waters first, then spreading across the central waters. Expect widespread gusts to 35 kt, with a few gusts possibly approaching 40 kt over the northern waters. Increasing southerly wind waves along with westerly swell will create hazardous seas, with significant wave heigheights peaking between 15 and 18 ft. Therefore, a Gale Warning is currently in effect for the northern waters, with Gales in the central waters Friday morning.
Winds will rapidly decrease from north to south Friday afternoon and evening, most likely falling below 20 kt by early Saturday morning. Seas will also subside below 10 ft by Saturday morning as high pressure begins to build in. Conditions will then remain steady into early next week as the high pressure continues to build into Sunday. /42
.PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory until 11am PDT Saturday for Coastal waters from Cape Shoalwater WA to Cascade Head OR out 10 NM-Columbia River Bar-Waters from Cape Shoalwater WA to Cascade Head OR from 10 to 60 NM.
Gale Warning until 2pm PDT this afternoon for coastal waters from Cascade Head OR to Florence OR out 60 NM.