Area Forecast Discussion
Issued by NWS Portland, OR

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174 FXUS66 KPQR 102245 AFDPQR Area Forecast Discussion National Weather Service Portland OR 345 PM PDT Thu Jul 10 2025 .SYNOPSIS...
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Partly cloudy skies with seasonable temperatures this afternoon. Temperatures warm up tomorrow into the weekend as high pressure builds. Expect morning marine clouds along the coast and over the waters. Temperatures cool slightly on Monday, but still remain very warm and dry. An Extreme Heat Watch has been issued for some interior valley locations from Tuesday to Wednesday next week as temperatures between 95 to 105 degrees are possible with overnight lows struggling to fall below 65 to 70 degrees.
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&& .SHORT TERM...
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Now through Saturday night...Satellite imagery as of early Thursday afternoon depicts partly cloudy skies and dry conditions across most of northwest Oregon and southwest Washington. Afternoon highs today are forecast to peak in the upper 70s to low 80s across interior locations, which is near or slightly below seasonal norms. Tomorrow (Friday), an upper level ridge begins to re-build, leading to warmer temperatures and sunny skies. Do expect some marine fog/stratus as high pressure aloft keeps clouds to the lowest part of the atmosphere. Friday afternoon highs are forecast in the upper 80s across interior valleys while the coast remains mild in the 60s to low 70s with onshore flow. Expect breezy northwesterly winds along the coast with gusts up to 25 mph, while northerly winds gust up to 20 mph across the Willamette Valley. The strongest winds will be in the afternoon when pressure gradients are tightest. High pressure persists on Saturday, maintaining similar temperatures to Friday with generally northerly flow. -Alviz
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&& .LONG TERM...
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Sunday through Wednesday...Ensemble guidance suggests that high pressure this weekend peaks on Sunday, leading to very warm temperatures in the low to mid 90s across the Willamette Valley. This will lead to widespread Moderate HeatRisk - this level of heat affects most individuals sensitive to heat, especially those without effective cooling and/or adequate hydration. We will continue to evaluate if a Heat Advisory is warranted for this weekend (particularly Sunday). On Monday, temperatures fall about 5-10 degrees as most ensemble guidance suggests an upper level shortwave trough dipping into the Canadian Rockies and northern Intermountain West. Though 500 mb heights fall over our area with this shortwave trough, they still remain above-normal and will maintain warm temperatures with highs in the upper 80s to low 90s for interior valleys. All eyes are on Tuesday to Wednesday as there is potential for extreme heat. An Extreme Heat Watch has been issued from Tuesday afternoon (July 15) to late Wednesday evening (July 16) across the Greater Portland/Vancouver Metro, Western and Central Columbia River Gorge, the Corbett area and the Hood River Valley, Lower Columbia River and Cowlitz River Valleys, and Central Willamette Valley. Dangerously hot conditions with temperatures between 95 to 105 degrees are possible. Low temperatures between 65 to 70 degrees are possible as well, which would limit overnight relief especially Tuesday night. Currently, this Watch encompasses areas where overnight low temperatures may struggle to fall below 65 to 70 degrees. The latest guidance suggests that there is a 40-50% chance that Tuesday night low temperatures remain above 70 degrees. In addition, there is also a 20-40% chance that Tuesday and Wednesday high temperatures exceed 105 degrees across the Willamette Valley. As a reminder, an Extreme Heat "Watch" is issued when dangerous heat is possible. An Extreme Heat "Warning" is issued when dangerous heat is happening or about to happen. Major HeatRisk is currently forecast for areas within the Extreme Heat Watch. This level of heat would affect anyone without effective cooling and/or adequate hydration. Heat related illnesses increase significantly during extreme heat events. In addition to the upper level high pressure, models are also indicating a thermal trough developing over the Willamette Valley on Tuesday. If this occurs, then it would lead to more offshore flow. Currently, the easterly winds forecast with this thermal trough are not looking very strong, and will mainly be through the Columbia River Gorge and Cascades. Current guidance shows pressure gradients of -2 to -4 mb through the Gorge on Tuesday, which would lead to wind gusts up to 20-25 mph in that area. -Alviz
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&& .AVIATION...
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Marine stratus across the air space continues to scour out resulting in a mixture of VFR/MVFR conditions across the airspace. Currently, winds are northerly around 5-10 kt, but expected to increase over the next few hours. This will result in gusty conditions for all terminals, with gusts up to 20 kt through around 02Z Friday. Westerly flow continues across NW Oregon and SW Washington through the TAF period. As a result, expect similar conditions as to what has been observed over the past 24-48 hours. Expect coastal conditions to redevelop IFR/LIFR conditions around 00Z-03Z Friday. For inland locations, while onshore flow will be present, it will be northerly and this pattern will mitigate marine stratus infiltrating through the gaps and flows as well as the Columbia River. However, models are showing some backbuilding clouds off the Cascades and that could bring some MVFR flight conditions to northerly (KPDX,KTTD,KVUO) and south/central (KSLE and KEUG) terminals. These conditions will likely start around 10Z-12Z Friday. Conditions across the airspace to slowly improve starting around 12Z-15Z Friday. PDX AND APPROACHES...Predominately VFR conditions through the majority of the TAF period. Backbuilding clouds off the Cascades will likely bring MVFR conditions to the the terminal and eastward starting around 12Z Friday. Conditions expected to improve back towards VFR around 16Z-18Z Friday. Northerly winds 5-10 kt, with gusts up to 20 kt possible through around 02Z Friday. /42
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&& .MARINE...
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North/northwest winds across all waters will persist through the weekend as a broad area of high pressure and a thermally induced trough spreads northward. As the high pressure and associated thermally induced trough mature, expect gusty northerly winds and choppier wind driven seas. As a result have issued a Small Craft Advisory for Zones PZZ237,PZZ253, PZZ272 and PZZ252 starting Friday morning and continuing through at least early Saturday morning. /42
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&& .PQR WATCHES/WARNINGS/ADVISORIES...
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OR...Extreme Heat Watch from Tuesday afternoon through Wednesday evening for ORZ108>115-119>122. WA...Extreme Heat Watch from Tuesday afternoon through Wednesday evening for WAZ204>207-209-210. PZ...Small Craft Advisory from 2 PM to 11 PM PDT Friday for PZZ252- 272. Small Craft Advisory from 11 AM Friday to 2 AM PDT Saturday for PZZ253-273.
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