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

VFR conditions remain in place across the airspace as surface high pressure continues to build offshore, but chances increase for MVFR cigs within marine stratus overnight. Along the coast, confidence in higher (60-80% chance) in bkn-ovc cigs at 1.5-2.5 kft, although there are 25-35% chances cigs fall to IFR, highest chances along the north OR and south WA coast near KAST. Gusty north winds will ease overnight, before restrengthening Sunday morning to near 15 kt with gusts around 25 kt through the afternoon and evening.

Inland, confidence in lower in the development of MVFR cigs with 35-55% chances, generally increasing northward along the Willamette Valley and to the east near the Cascade foothills. Highest chances are in the Portland area including KPDX and KTTD, with cigs at 2-3 kft most likely from 12-16z Sun. Low cloud coverage is likely to peak at the same time at other terminals, but confidence is too low to include explicit MVFR cigs at this time. Low clouds will tend to mix out by 17-19z Sun, with widespread VFR conditions very likely through the afternoon. North winds along the Willamette Valley and northwest winds in the Portland area will continue through the period, easing to around 5 kt tonight before strengthening to 8-12 kt by Sunday afternoon. Gusts around 20 kt are most likely along the Willamette Valley.

KPDX AND APPROACHES...VFR conditions expected to prevail into tonight before chances for MVFR cigs within low stratus increase to 50-55% after 10-12z Sun. Confidence is marginally higher at KTTD, but have included explicit MVFR cigs at KPDX overnight as well. Low cloud coverage will peak from 12-16z Sun before mixing out through the early afternoon, with a return to largely clear skies and VFR conditions by 18-19z Sun. Northwest winds ease to 5 kt or less this evening, then increase to around 10 kt by Sunday afternoon. -36

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.