textproduct: Portland

SYNOPSIS

Warm and sunny conditions continue through Monday as high pressure builds over the region. This will result in localized Moderate HeatRisk. An upper-level trough moving into British Columbia Tuesday to Wednesday will cool temperatures a few degrees and bring slight chances for precipitation along the south Washington coast. Seasonable temperatures return Thursday to Friday with persistent onshore flow. Make sure to practice water safety when swimming in local rivers.

LONG TERM...Tuesday through Saturday

Ensemble models continue to show minimal change in the overall forecast. Said models continue to show an upper-level trough from the Gulf of Alaska moving east/southeastward into British Columbia and de- amplifying an upper-level high pressure anchored over The Great Basin. Models continue to keep the Alaskan system north of the region, which will keep the region dry, but will help to maintain relatively cooler onshore flow. Onshore flow looks to increase by the middle of the week and will help to keep the CWA a few degrees closer to seasonal normals for early July. West- northwesterly winds are generally expected to be light for most areas through the end of the week. However, will see locally breezier winds along the central Columbia River Gorge and Upper Hood River Valley, where there is a 10-30% chance for at least isolated wind gusts exceeding 40 mph Tuesday and Wednesday.

At the end of next week and into next weekend, most ensemble members show the aforementioned trough weakening as it moves eastward through British Columbia. At the same time, ensemble members are showing additional troughing moving down from the Gulf of Alaska into the northeast Pacific/British Columbia. There still remains uncertainty with the exact placement and magnitude of this additional troughing, thus uncertainty with any potential impacts at this time. If this pattern does pan out, this would support continued onshore flow with seasonable temperatures and little to no precipitation. /42-10

AVIATION

Generally VFR conditions remain in place across most of the airspace as surface high pressure continues to build, but chances increase for MVFR cigs developing through 18Z Sunday across the airspace. Along the coast, 60-80% chance in MVFR and 25-35% chance for IFR conditions to develop through 18Z Sunday. Highest chances along the north OR and south WA coast near KAST. For inland locations, back building clouds from the Cascades are resulting in a 10-40% chance of MVFR conditions impacting locations within the Willamette Valley. Highest chances are in the northern Willamette Valley, primarily for KPDX, KVUO, KTTD, KHIO and KUAO through 18Z Sunday. Any lowered flight conditions should improve to VFR around 18Z-20Z Sunday and persist through around 06Z-08Z Monday, when marine stratus is expected to return and impact coastal locations.

Northerly winds persist around 5-10 kt and are expected to strengthen to 8-12 kt around 23Z Sunday through 03Z Monday for inland locations. Along the coast, northerly winds also persist around 7-12 kt and are expected to strengthen to 8-15 kt around 20Z Sunday through 06Z Monday. Gusts up to 25 kt expected along the coast and gusts up to 20 kt within the Willamette Valley.

KPDX AND APPROACHES...VFR conditions expected through the majority of the TAF period. 20-40% chance of backbuilding MVFR cigs developing through 18Z Sunday, with any lowered flight conditions should improving back to VFR afterwards. Northerly winds persist around 5-10 kt and are expected to strengthen to 7-12 kt around 00Z Monday, with gusts up to to 20 kt. /42

MARINE

High pressure over the region is resulting in increasing winds and building seas through Monday. Northerly winds will continue to slowly increase through this afternoon with gusts up to 30 kt expected. Seas will build from 4 to 6 ft towards 6 to 8 ft through today as well. Highest winds expected in zones PZZ252, PZZ253, PZZ272 and PZZ273. Therefore, will maintain the current suite of Small Craft Advisories through tonight. Conditions ease Monday night into Tuesday as high pressure gives way to a broad upper level trough moving southeastward out of the Gulf of Alaska, which will bring about relatively benign conditions through the remainder of the week. /42

PQR WATCHES/WARNINGS/ADVISORIES

OR...None. WA...None. PZ...Small Craft Advisory until 2 AM PDT Monday for PZZ251>253- 271>273.