Cape Shoalwater WA to Cape Lookout OR between 60 and 150 NM Offshore Forecast
| Today...N Winds 15 To 20 Kt. Seas 6 To 9 Ft. |
| Tonight...N Winds 15 To 20 Kt. Seas 7 To 9 Ft. |
| Wed...N Winds 10 To 20 Kt. Seas 7 To 9 Ft. |
| Wed Night...N Winds 15 To 25 Kt. Seas 7 To 9 Ft. |
| Thu...N Winds 10 To 20 Kt. Seas 7 To 10 Ft. |
| Thu Night...N Winds 10 To 20 Kt, Becoming 10 To 15 Kt. Seas 7 To 9 Ft. |
| Fri...N To Nw Winds 10 To 20 Kt, Becoming Nw 10 To 15 Kt. Seas 6 To 8 Ft. |
| Fri Night...Nw Winds 10 To 15 Kt, Becoming W To Nw 5 To 10 Kt. Seas 6 To 7 Ft. |
| Sat...Variable Winds Less Than 10 Kt, Becoming N To Nw. Seas 5 To 6 Ft. |
| Sat Night...N Winds Less Than 10 Kt, Becoming Variable. Seas 5 To 7 Ft. |
| Area Forecast Discussion National Weather Service Portland OR 1038am PDT Tuesday April 7 2026 Synopsis Dry conditions will persist through Friday aside from a chance of showers and thunderstorms over the Oregon Cascades, mainly on Thursday and Friday. A dry cold front will bring noticeably cooler temperatures today and Wednesday. Trending relatively warmer again Thursday into Friday with light offshore flow developing. Becoming cooler again over the upcoming weekend with increasing chances for showers. .SHORT TERM...Now through Friday Night...Satellite and surface weather observations from early Tuesday morning showed a weak dry cold front progressing southward across the southwest WA and northwest OR. Low marine stratus at the coast is already beginning to scatter out behind the frontal passage, and the HREF ensemble mean for cloud cover suggests overcast skies should become partly cloudy by mid to late Tuesday morning. Note skies will clear out along the south WA/north OR coast first and the central OR coast last. Meanwhile, inland areas will most likely remain clear aside from a few exceptions. One exception is along the lower Columbia, the south WA Cascade foothills, and the Cowlitz Valley, as these areas already have broken low cloud cover in place. In addition, the central and southern Willamette Valley may see low clouds develop later this morning (20-50% chance according to the latest HREF guidance, with the highest probabilities in the southern Willamette Valley). Probabilities are much lower for the Portland metro and northern Willamette Valley at 5-15%. Regardless of the exact outcome, confidence is high conditions will be mostly sunny across all of northwest OR and southwest WA this afternoon, allowing temperatures in the lowlands to warm into the mid 60s, except 50s along the coast. Very little change is expected to the weather pattern heading into Wednesday. That said, a full day of sun (aside from some thin scattered high clouds) will favor afternoon temperatures peaking a few degrees warmer compared to Tuesday for inland areas. Despite the slightly warmer temperatures Wednesday afternoon, it will be quite chilly in the morning with widespread morning lows in the 30s. The coldest temperatures are expected over southwest WA, the north OR Coast Range, and the Upper Hood River Valley; these areas have forecast lows ranging between 33-36 degrees. Given the clear skies and calm winds in place, this will support frost development. Therefore, a Frost Advisory has been issued for the aforementioned zones for the Tuesday night and Wednesday morning time frame. Anyone with sensitive outdoor vegetation that is susceptible to frost damage should take necessary precautions today. Beyond Wednesday, model ensemble guidance continues to show a brief warming trend Thursday through Friday due to shortwave ridging on the northeast periphery of an upper level low centered off the northern/central California coast. The latest iteration of the deterministic NBM has boosted high temperatures by 1-3 degrees compared to previous cycles, and now suggests inland valleys will warm to 71-75 degrees both Thursday and Friday. Coastal areas should remain relatively cooler with highs around 60-65 degrees. Probabilities for highs of 75 degrees or warmer have increased to 50-75% in the Portland metro on Thursday and to 15-20% across the Willamette Valley and Cascade valleys. In regards to precipitation, expect the ongoing dry spell to persist through Friday, aside from the Oregon Cascades where chances for showers and thunderstorms begin to increase Thursday afternoon, especially to the south of Mount Hood. This is because models and their ensembles continue to show a period of increasing southerly to southeasterly flow aloft Thursday into Friday as the aforementioned upper low slowly moves towards the central California coast. This synoptic-scale setup will favor increasing moisture and instability, however there is still some uncertainty in regards to how moist and unstable the thermodynamic profile will become. The NBM 10th-90th percentile for SBCAPE values over the Oregon Cascades and foothills ranges from near 0 J/kg all the way up to 400-900 J/kg, with mean values around 100-200 J/kg. Note forecast soundings over the Cascades suggest storms would be surface-based and mainly tied to diurnal heating if they do occur. Given what looks to be a weak wind shear profile, severe thunderstorms are unlikely to occur, however isolated stronger storms cannot be completely ruled out as suggested by the NBM 90th percentile for SBCAPE. For now, NBM Probability of Precipitation and thunder probabilities seem reasonable given the ongoing uncertainty involved. Probability of Precipitation peak near 50-70% Thursday afternoon/evening and near 60-80% Friday afternoon/evening, suggesting showery activity is likely. The thunderstorm potential is relatively lower, with thunder probabilities peaking near 10-20% on Thursday and near 15-25% on Friday. Note if upper level flow does become southeasterly with convection developing over the Cascades, a few stray cells would have the potential to drift into the Willamette Valley, Coast Range, and/or Portland metro. -23 Long Term Saturday through Monday...A pattern change is still expected this upcoming weekend, though details remain uncertain at this time. 500 mb cluster analysis shows that the majority of ensemble guidance indicates a trough originating from Alaska will approach the PacNW from the northwest early Saturday morning into Sunday, bringing the return of widespread precipitation chances. However, there are a number of differences in the timing and amplitude of this trough as well as how it interacts with the pre-existing low pressure system along the California coast. These differences impact the overall forecast, though one aspect that the ensembles agree on is temperatures will be trending noticeably cooler with low chances for any high impact weather. For example, afternoon high temperatures in the 70s late in the week will cool into either the 50s or 60s beginning Saturday. The NBM 1D Viewer highligheights this well, suggesting inland high temperatures could range anywhere from the lower 50s to mid 60s Saturday through Monday per the 10th-90th percentile guidance. Chances for showers are currently highest on Saturday and Sunday during the afternoon/evening hours, peaking between 40-60% west of the Cascades and 60-80% over the Cascades. Guidance continues to suggest rain amounts will most likely be on the lighter side if precipitation does occur. Probabilities for 48-hour rain totals below 0.25 inches from 5am Saturday through 5am Monday remain around 50-65%, except 25-35% over the Cascades. -23 Marine A weak cold front will progress southward across the coastal waters early Tuesday morning, bringing clearing skies and improving visibilities. No precipitation or significant wind shifts are expected with this frontal passage, as winds should remain out of the north to north-northwest around 15-20 kt. However, a fresh northwesterly swell is still on track to arrive behind this frontal passage late Tuesday morning into the afternoon. This will push seas up to 6 to 8 ft with a dominant wave period of 8 to 9 seconds, resulting in steeper waves that will be hazardous to small craft. Therefore, a marginal Small Craft Advisory remains in effect from 5am Tuesday through 5am Wednesday. Note brief wind gusts up to 25 kt may occur with the frontal passage. Seas are still on track to decrease slightly to 5 to 7 ft on Wednesday and then remain within that range through the upcoming weekend, with winds likely staying under 20 kt. However, another round of marginal Small Craft Advisory conditions cannot be ruled out late in the week, especially on Thursday when there is a 25-50% chance for max wind gusts over 21 kt over the northern and southern waters and a 40-65% chance over the central waters. In addition, seas are forecast to become slightly steeper again. -23 NOAA Portland OR Office: Watches - Warnings - Advisories OR...Frost Advisory from 11pm this evening to 9am PDT Wednesday for ORZ104-106-108-109-114>118-121. WA...Frost Advisory from 11pm this evening to 9am PDT Wednesday for WAZ202>206-208. PZ...Small Craft Advisory until 5am PDT Wednesday for PZZ251>253- 271>273. |
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