Area Forecast Discussion
Issued by NWS Portland, OR
Issued by NWS Portland, OR
569 FXUS66 KPQR 101802 AAA AFDPQR Area Forecast Discussion...UPDATED National Weather Service Portland OR 1102 AM PDT Wed Jul 10 2024 Updated aviation discussion... .SYNOPSIS...Finally, the heat has ended. Well, mostly. Will still have a warm day across the interior, but highs mainly in the 80s to middle 90s for the warmest spots. Lot cooler along the coast, where low clouds and fog will keep it in the 50s to middle 60s today. Overall, not much change through rest of the week, as high pressure will maintain dry condition, with warm temperatures inland. But, again, not as hot as recent days. && .DISCUSSION...(Today through next Tuesday)...Finally, a long awaited change in the weather pattern. Increasing southwest flow offshore into the Pacific NW has pushed the pesky hot upper ridge east of the region, with its axis now over Idaho southward over the Great Basin states. With this shift, will also see an uptick in the onshore flow. As of 2 am, marine low clouds and even fog blanketed the coastal regions, with those clouds jamming up into the coastal river valleys of the western Coast Range and Willapa Hills. That will keep the coastal region cooler, with highs in the 50s to upper 60s. But, onshore flow is not strong enough to push the clouds too far inland. As such, will just have the moderating effect of high humidity as that ocean air seeps inland. But, that, along with the heart of the ridge to the east, will bring more manageable temperatures to the interior. Overall, most areas inland will see temperatures get into the middle 80s to middle 90s inland, with the warmest being from Portland to Salem area, and towards the Hood River valley. Overall, not much pattern change through rest of the week into the coming weekend, as will maintain warm southwest flow aloft. This will keep inland areas warm, with highs in the 80s to lower 90s. Interestingly, models still hinting that afternoon highs very well could be around or just above 90. Model guidances suggests that there is a 50-75% chance that temperatures will top out above 90. Best chance of staying below 90 is Thursday, as least wise until next week. This table shows the chance for high temperatures being above 90 deg for select spots across the region: Chance of Daily MAX Temperature being above 90.... WED THU FRI SAT SUN MONTUE Kelso 15% 1% 10% 20% 10% 5% 1% Portland 95% 40% 60% 75% 65% 45%25% Salem 100% 45% 65% 90% 65% 60%30% Eugene 100% 45% 65% 80% 60% 50%25% Hood River 100% 80% 90% 95% 85% 60%30% Finally, there is general agreement in the ensemble guidance that core of the high pressure will shift from southern Nevada (WED/THU) more towards the Four Corners region for FRI into this weekend. This will open the door to monsoonal moisture working its way around the high pressure. At this point, most ensemble guidance suggests the moisture and thunderstorm chances will remain well south and east of the region, but there is a 5-10% chance that the thunderstorm threat impacts our Cascades by the end of the weekend. Longer range shows that will see uptick of onshore flow next week, with temperatures across the region being more seasonal. That is, with 60s to lower 70s on the coast, and lower to middle 80s inland. Ahh, welcome news for those weary of the hot weather of the past 5 days. /Rockey && .AVIATION...High pressure remains over the area, maintaining VFR thresholds under clear skies for inland terminals. Based on model guidance, IFR/MVFR marine stratus along the coast should begin to dissipate by 19-20z Wed, improving conditions to VFR. Pressure gradients tighten this afternoon, returning gusty winds. Expect northerly to northwesterly winds for all terminals with gusts to around 20 kt. Late evening, expect winds to weaken below 10 kt. As the coast cools down tonight, there is high confidence in marine stratus returning which will bring IFR/MVFR conditions to KAST and KONP. There is also a 15-30% chance of IFR/MVFR cigs for northern Willamette Valley terminals between 12-16z Thu, as model guidance hints at marine stratus potentially filtering in through the Lower Columbia River Valley. PDX AND APPROACHES...VFR under clear skies through the TAF period, with a 15-20% chance of IFR cigs between 12-16z Thu. Winds this afternoon will be northwesterly 10-13 kt, with gusts around 20 kt. -Alviz && .MARINE...High pressure continues to move east, resulting in gradually decreasing pressure gradients. Seas will mainly be wind- driven, between 3 to 5 feet. Pressure gradients tighten again Wednesday evening, increasing winds into small craft advisory criteria. Given confidence is high, a Small Craft Advisory has been issued to go in effect from 5 PM Wednesday to 2 PM Thursday for all inner and outer waters. Seas will remain between 5 to 7 ft through this timeframe. -JH && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory from 5 PM this afternoon to 2 PM PDT Thursday for PZZ251>253-271>273. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland www.twitter.com/NWSPortland