Cascade Head to Florence OR from 10 to 60 NM Marine Forecast
|Today...Sw Wind 10 To 15 Kt, Easing To 5 To 10 Kt With Gusts To 15 Kt Late Afternoon. Wind Waves Sw 2 Ft At 4 Seconds. Nw Swell 10 Ft At 11 Ft Subsiding To 7 Ft.|
|Tonight...S Wind 5 To 10 Kt With Gusts To 15 Kt, Rising To 10 To 15 Kt With Gusts To 20 Kt After Midnight. Wind Waves S 2 Ft At 4 Seconds. Nw Swell 7 Ft At 12 Seconds.|
|Mon...Sw Wind 10 To 15 Kt With Gusts To 20 Kt, Becoming Nw 5 To 10 Kt With Gusts To 15 Kt In The Afternoon. Wind Waves W 2 Ft At 5 Seconds. Nw Swell 8 Ft At 15 Seconds. Chance Of Rain In The Afternoon.|
|Mon Night...N Wind 10 To 15 Kt. Gusts To 20 Kt In The Evening. Wind Waves N 3 Ft At 4 Seconds. Nw Swell 11 Ft At 14 Seconds.|
|Tue...Nw Wind 10 Kt. Gusts To 15 Kt In The Morning. Wind Waves Nw 2 Ft At 4 Seconds. Nw Swell 12 Ft At 14 Seconds.|
|Tue Night...Sw Wind 5 To 10 Kt. Wind Waves Sw 2 Ft At 4 Seconds. Nw Swell 10 Ft At 14 Seconds.|
|Wed...S Wind 10 To 15 Kt, Rising To 20 To 25 Kt. Wind Waves 3 Ft, Building To 6 Ft. Nw Swell 8 Ft.|
|Thu...S Wind 25 To 30 Kt. Combined Seas 17 Ft.|
| Area Forecast Discussion|
...UPDATED National Weather Service Portland OR
918am PST Sunday Feb 28 2021
Updated Short-term and Aviation sections
It will begin to feel a bit more like Spring over the coming days as valley temperatures moderate into the 50s and quite possibly climb into the 60s by Thursday. A few bouts of light rain will be possible through late Monday, but a more substantial storm system will likely bring higher valley rain and mountain snow totals late next week.
Today through Tuesday...Update for this morning to adjust sky cover. Morning clouds are retreating north faster than we had indicated. Given this, had also considered increasing temperatures with the added sun. Slightly warmer temps may still be the case, however, suspect fair weather cumulus will develop for many areas across the north to mitigate some of the incoming sunlight. Fair weather Cumulus clouds sees less likely for the south valley where dew points are lower, however, we were already on the warm side of guidance so opted to leave temperatures alone across the board. /JBonk
Previous discussion from 308 AM: Water vapor satellite imagery early this morning shows a shortwave ridge over the eastern Pacific pushing into the Pacific Northwest. Weak isentropic lift along a warm frontal boundary near the coast has resulted in some spotty light rain and drizzle across primarily southwest Washington and along the far north Oregon coast overnight. Models are in reasonable agreement this lift will more or less persist across our far northern zones through midday before gradually waning this afternoon. The end result is that morning clouds should thin from south to north today. Most locations away from our far northern zones will remain dry with near average temperatures for the last day of February expected.
Shortwave ridging will take hold tonight into Monday. Clear skies and light winds may allow for some patchy morning valley fog to develop. Models and their ensembles continue to suggest a dying front will push southeastward towards the south Washington and north Oregon coast on Monday or Tuesday. Ensemble data suggests there is still a chance this could result in some light rain, particularly late Monday near the coast and across our northern zones, but more and more models suggest most of the area will remain dry. Models remain in good agreement shortwave ridging will re-establish itself over the region going into Tuesday and result in another dry day across the region with near average temperatures. /Neuman
Tuesday night through Sunday...The majority of models and their ensembles continue to suggest a cutoff low pressure will slide eastward across southern California and the Desert Southwest during the middle part of next week. Meanwhile, zonal flow will exist across the northern Pacific Northwest and southern Canada. Southwest Washington and northwest Oregon should be far enough removed from the storm track to our north and south that we should see a continuation of dry weather midweek.
It appears the pattern will begin to change later next week into next weekend, though. Models and their ensembles are in relatively good agreement a large shortwave trough will slide into the eastern Pacific during the latter half of the week. Shortwave ridging will become more amplified over the Pacific Northwest. This should allow for temperatures to moderate with more and more model guidance suggesting high temperatures will climb into the low 60s by Thursday.
The uncertainty in the forecast continues to be in how quickly the aforementioned shortwave trough in the eastern Pacific slides into the western US. ~70% of ensemble guidance suggests it will hold off until at least late Thursday or later. The odds precipitation holds off until late Friday appears to decrease substantially...generally in the 20-40% range, but nonetheless, not an insignificant chance. Snow levels will likely start off well above the Cascades passes as the first round of precipitation tied to the front moves into the region. However, snow levels appear likely to fall below the Cascades passes behind the front as additional showers spread eastward into the region.
Otherwise, model and ensemble guidance continues to suggest additional shortwave troughs of varying magnitudes and timing will slide into the eastern Pacific and Pacific Northwest over the weekend. As a result, will maintain Probability of Precipitation in the 40-70% range with temperatures cooling back down closer to average or even back below average by late in the weekend. /Neuman
A ridge of weak high pressure over the central Oregon coast waters lingers through Monday. Meanwhile a splitting front will slowly approach the coast. But model trends show the front will be weaker as it approaches the coast, and should dissipate just offshore late Monday. High pressure then rebuilds across the waters while lower pressure remain to the northwest.
For today seas will be under 10 ft except for the central waters may linger near 10 ft until about 7 am, and south winds less than 20 kt. A weakening front well offshore gradually approaches the coast through Monday increasing the pressure gradient slightly tonight. Recent model runs have backed off on Small Craft Advisory winds tonight for PZZ270 so have done the same.
The next system in the late Thursday early Friday time frame. This front appears to be much more robust than the systems earlier in the week. Some global models are suggesting near gale force gusts near 40 kt while others are staying more in the 25 to 30 kt range. Similarly, seas will be impacted by a secondary fresh swell that happens to be the more energetic of the two. Could see combined seas in the 15 to 20 ft range, but confidence remains quite low. Decided to stay conservative in regards to both winds and seas with the forecast a blend of the ECMWF (European Centre for Medium-Range Weather Forecasts) and the stronger GFS solution. /mh
.PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory from 4pm this afternoon to 9pm PST this evening for Columbia River Bar.