Area Forecast Discussion
Issued by NWS Portland, OR
Issued by NWS Portland, OR
498 FXUS66 KPQR 140439 AAA AFDPQR Area Forecast Discussion...UPDATED National Weather Service Portland OR 938 PM PDT Sun Jul 13 2025 ...Updated aviation discussion and WWA section... .SYNOPSIS...A Heat Advisory remains in place through tonight for most interior valleys. Expect sunny skies across the area with morning marine stratus/fog along the coast. Temperatures cool slightly on Monday, but still remain warm and dry. An Extreme Heat Watch continues for some interior valley locations from Tuesday to Wednesday, as afternoon temperatures between 90 to 100 degrees and low temperatures between 65 and 70 degrees are possible. Extreme Heat could also extend through Thursday. && .SHORT TERM...Tonight through Wednesday Night...Elevated daytime highs will result in warm overnight temperatures. So, will maintain the Heat Advisory through at least 10 pm tonight. Relatively cooler, onshore flow is expected as a broad, upper level trough from western Canada starts to slide south/southeastward into far eastern Washington/eastern Oregon. While this won`t bring any significant weather to our CWA. It will bring some cooler 850 mb temperatures around 14C to 16C degrees. This will result in daytime highs on Monday into the low to upper 80s. North/northwest winds will again increase during the afternoon as surface high pressure offshore and low pressure east of the Cascades increases the pressure gradient. Expect wind gusts up to 20-25 mph inland, while gusts up to 30 mph will be possible along the central Oregon coast. As we move into Tuesday and Wednesday, hot and dry days are back on the menu. The primary synoptic features will be a very broad upper level high and a surface low within the Great Basin. The upper level high will expand across the Pac NW and eastward towards the Rockies. As this upper level high strengthens it will amplify a surface low within the Great Basin. The low within the Great Basin will spread northward as well as expand east and west. This will result in very warm 850 mb temperatures around 19C to 22C to mix down to the surface. Here is a table for some locations across our forecast area. It will have forecasted highs as well as record highs for Tuesday and Wednesday, if they are available: Tues (Record/Yr) Weds (Record/Yr) Portland 92 (103/1941) 98 (104/1979) Vancouver 92 (103/1941) 98 (101/1941) Salem 93 (108/1941) 99 (103/1979) Eugene 92 (102/1941) 97 (102/1979) Kelso/Longview 90 95 Battle Ground 91 96 Astoria 74 (86/1979) 74 (87/1979) Newport 70 72 The current forecast does not have record breaking heat for our area. However, some areas do have a small probability of seeing triple digit heat on Tuesday and Wednesday. For Tuesday, the Willamette Valley has a 5%-25% probability of reaching daytime highs of 100 degrees Fahrenheit, with locations in the Central and Southern Willamette Valley having the higher probabilities. For Wednesday, the Willamette Valley has a 50%-70% probability of reaching daytime highs of 100 degrees Fahrenheit, with locations in the Central and Southern Willamette Valley having the higher probabilities. Overall, while Monday will be relatively cool for the forecast area, Tuesday and Wednesday will be hot and dry. Wednesday is on track to be the hottest day this week, with most inland areas having the potential to see daytime highs in the triple digits. Given the hot days to come, HeatRisk remains Moderate, with some locations falling into the Major HeatRisk category. Take the necessary heat precautions as hot temperatures may lead to heat illnesses. /42 .LONG TERM...Thursday through Saturday...As we move into the latter part of this week and into the weekend, models are showing a slight cooling trend for the region. While Thursday daytime highs are expected to be in the low 90s for the Willamette Valley (this could result in an extension of the Tuesday and Wednesday Heat Headlines), there is some cooler weather on the horizon. The broad, upper level high looks to break down thanks in part to a series of upper level lows swinging down out far western Canada. WPC 500 mb Clusters are at least leaning towards a series of weak lows for the latter part of the week. Will continue to monitor, but the overall trend for the Long Term forecast does maintain dry conditions, but daytime highs looks to cool towards the mid to upper 80s for the Willamette Valley, upper 70s to mid 80s for the Cascades and low to upper 60s along the coast. /42 && .AVIATION...Tonight, high pressure will maintain VFR conditions with clear skies inland and LIFR/IFR marine stratus along the coast. Between 14-17z Mon, guidance suggests a 15-30% chance for MVFR stratus developing around the Portland/Vancouver Metro Area. Any morning stratus inland should scatter out by 17-19z Mon as daytime heating progresses. VFR conditions with mostly sunny skies prevail inland through the rest of the TAF period. A shortwave trough will also move over the region Monday morning, allowing marine stratus along the coast to lift to more IFR/MVFR thresholds by 18-21z Mon. No precipitation is expected with this shortwave. Expect breezy northerly to northwesterly winds across the area with gusts up to 25-30 kt along the coast and 20-25 kt inland, strongest in the afternoon. PDX AND APPROACHES...Predominately VFR through the TAF period with mostly clear skies. Guidance suggests a 15-30% chance for MVFR CIGs between 14-17z Mon. Stratus will be difficult to form given the overall drier air mass, so if it does form it would be short-lived. Light northwesterly winds overnight under 10 kt, strengthening Monday afternoon with gusts up to 20 kt. -Alviz && .MARINE...Broad area of high pressure over the Pacific will keep conditions fairly persistent over the next few days. Upwelling along the coastline is producing low cloud cover and fog in the inner waters and the Columbia River Bar. Given the trend over the last few days, have issued a Dense Fog Advisory through Monday morning. On Monday, a weak disturbance will move over the region. Will see cooler temperatures, northwesterly flow, and building seas. Winds remain elevated through early Monday morning before easing, and a fresh swell moves in. The Small Craft Advisory currently issued for winds will likely transition to a wave based advisory late Monday. however, conditions are borderline so if there is any limitation of the wind waves, overall significant wave heights will be less. High pressure rebuilds through the week with a typical summer pattern of northerly winds as a thermal trough forms along the coast.-Muessle && .PQR WATCHES/WARNINGS/ADVISORIES... OR...Heat Advisory until 10 PM PDT this evening for ORZ108-109-111- 112-114>118-120>122. Heat Advisory from noon Tuesday to 10 PM PDT Wednesday for ORZ108>122. WA...Heat Advisory until 10 PM PDT this evening for WAZ204>207-209- 210. Heat Advisory from noon Tuesday to 10 PM PDT Wednesday for WAZ204>207-209-210. PZ...Dense Fog Advisory until 2 PM PDT Monday for PZZ210-251>253. Small Craft Advisory until 11 PM PDT Monday for PZZ251>253- 271>273. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland