textproduct: Portland

SYNOPSIS

Hot temperatures remains the main story through Monday, with very warm nights offering little relief and breezy offshore flow continuing into tonight. An Extreme Heat Warning remains in effect for the Greater Portland/Vancouver Metro and Columbia River Gorge through late Tuesday, with Heat Advisories elsewhere inland and along the coast today. Conditions ease somewhat Tuesday as onshore flow returns, though inland areas will remain warmer than normal through much of the upcoming week.

DISCUSSION...Sunday afternoon through Saturday

This Sunday afternoon, the forecast remains largely on track as upper-level ridging continues to strengthen over the eastern Pacific and the Pacific Northwest, while a surface thermal trough stays stretched across western Oregon and Washington. Temperatures have responded accordingly, with rapid warming already underway inland and along parts of the coast where offshore/downsloping flow has limited marine influence more than usual.

The hottest stretch of the forecast continues to center on this afternoon and Monday. Confidence remains high that most interior lowland locations will climb well into the 90s both days, with a meaningful chance that a few spots touch or exceed 100 degrees, especially on Monday (20-60% chance of 100+ degrees on Monday). Even today, localized 100 degree observations remain possible from Hillsboro south toward Aurora (25-45% chance of 100+ degrees today). Along the coast, today still appears to be the peak heating day as offshore flow supports compressional warming; several coastal communities have a reasonable chance of reaching the mid 80s, which is notable for mid-June. Earlier this afternoon, temperatures reached the upper 80s along the coast due to continued offshore flow, but has since decreased with the return of onshore flow.

A major contributor to heat impacts will be the lack of overnight recovery. Tonight is still expected to be the warmest night of the stretch, with widespread lows west of the Cascade foothills staying above 60 degrees and many areas having a decent chance of remaining above 65 degrees (45-65% probability of remaining above 65 degrees). A few urban and downslope locations, including parts of the Portland metro, western Willamette Valley, and central Coast Range, could even struggle to fall below 70 degrees (60-70% probability of falling below 70 degrees). Monday night into Tuesday morning should be slightly less extreme, but still quite mild for many inland areas (upper 50s to low 60s inland, mid to upper 50s at the coast).

Taken together, hot afternoons and unusually warm nights will continue to support widespread Moderate to Major HeatRisk through at least Monday west of the Cascades. That means heat- related illness becomes more likely, particularly for those without effective cooling, sensitive groups, and anyone spending prolonged time outdoors. Continue to prioritize heat safety: stay hydrated, limit strenuous afternoon activity, use air- conditioned spaces when possible, and check on vulnerable neighbors, family, and pets. Also remember rivers and lakes remain cold despite the hot weather, increasing the risk of cold-water shock for anyone seeking relief near the water.

In addition to the heat, breezy offshore winds and very low afternoon humidity will maintain some fire weather concern through Monday. The more favored wind-prone areas remain the central and southern Willamette Valley during the afternoon/evening and the Columbia Gorge/Cascade gaps overnight into early Monday morning. While fuels have not yet supported Red Flag headlines, the pattern of hot, dry, and locally breezy weather could still allow fires to start and spread in grasses and other fine fuels. Avoid activities that could produce sparks or accidental ignitions.

Relief begins to arrive late Monday into Tuesday as a shortwave moving into British Columbia weakens the ridge and disrupts the surface thermal trough. This should allow marine influence and onshore flow to work back inland. Even so, Tuesday does not look cool, just less hot, with highs still expected to reach the mid to upper 80s in the Willamette Valley and upper 70s to low 80s across the southwest Washington lowlands. Heat concerns may linger Tuesday as well, particularly in more urbanized locations where warm overnight lows and heat retention remain an issue.

Beyond that, ensemble guidance favors a continuation of generally warm and dry weather through much of the week. Wednesday and Thursday look seasonably to above-normal warm under weaker ridging, with perhaps some shallow morning coastal stratus returning at times. By late week into next weekend, a weak trough may try to flatten the pattern somewhat, but no major cool-down or widespread precipitation signal is evident at this time. ~12

AVIATION

High pressure will maintain VFR conditions with clear skies through the TAF period across all terminals. Surface pressure gradients tighten this afternoon, supporting breezy northerly to northeasterly winds across the area, with gusts up to 20-25 kt at any given terminal. After 01-03z Mon, winds should gradually weaken as pressure gradients ease, becoming variable around 5 kt or less inland with light offshore winds along the coast.

In addition, temperatures between 90 to 100 degrees F are forecast across the Willamette Valley through Monday. Be aware of high density altitude which may reduce aircraft performance.

KPDX AND APPROACHES...VFR with clear skies through the TAF period. ENE winds with gusts up to 20-25 kt are expected through the afternoon. Winds weaken in the evening after 01-03z Mon. /DH

MARINE

High pressure offshore will maintain the summertime pattern this weekend and through much of next week. A strengthening thermal trough along the coast will increase pressure gradients over the coastal waters again today. As such, northerly winds will increase to around 15-25 kt with gusts up to 25-30 kt south of Cape Falcon. Winds ease overnight into Monday morning, but are expected to increase again as diurnally driven northerlies peak each afternoon and evening through next week. Seas around 4 to 8 ft at 7-10 seconds are expected to persist, driven primarily by the northerly wind chop. Seas are expected to build to around 8 to 10 ft later in the week as a fresh northwesterly swell builds across the waters. /DH

CLIMATE... Record high temperatures and warm low temperatures for Sunday, June 14

High Temperatures: Warm Low Temperatures: Portland Int'l 89F (1988) 62F (1985) Vancouver, WA 93F (1986) 61F (1931) Hillsboro 96F (1961) 60F (1963) McMinnville 93F (1986) 59F (1936) Salem 92F (1961) 59F (1936) Eugene 92F (1914) 57F (1993) Astoria 86F (1914) 58F (1972)

Record high temperatures and warm low temperatures for Monday, June 15

High Temperatures: Warm Low Temperatures: Portland Int'l 95F (1966) 60F (1969) Vancouver, WA 95F (1930, 1966) 62F (1961) Hillsboro 99F (1961) 60F (1963) McMinnville 96F (1961) 59F (1936) Salem100F (1966) 59F (1931) Eugene 96F (1966) 60F (1961) Astoria 91F (1966) 58F (1997)

Record high temperatures and warm low temperatures for Tuesday, June 16

High Temperatures: Warm Low Temperatures: Portland Int'l 95F (1958) 60F (2012) Vancouver, WA 92F (1961) 67F (1966) Hillsboro100F (1961) 65F (1961) McMinnville 98F (1961) 59F (1966) Salem 97F (1961) 61F (1961) Eugene 95F (1961) 62F (1961) Astoria 87F (1958) 59F (1997)

PQR WATCHES/WARNINGS/ADVISORIES

OR...Heat Advisory until 11 PM PDT this evening for ORZ101>103. Heat Advisory until 11 PM PDT Tuesday for ORZ104>108-113>119- 121>125. Extreme Heat Warning until 11 PM PDT Tuesday for ORZ109>112- 120. WA...Heat Advisory until 11 PM PDT this evening for WAZ201. Heat Advisory until 11 PM PDT Tuesday for WAZ202>205-208-210. Extreme Heat Warning until 11 PM PDT Tuesday for WAZ206-207- 209. PZ...Small Craft Advisory from 3 AM to 7 AM PDT Monday for PZZ210. Small Craft Advisory until 5 AM PDT Tuesday for PZZ252-253-272- 273.