Area Forecast Discussion
Issued by NWS Portland, OR
Issued by NWS Portland, OR
987 FXUS66 KPQR 132122 AFDPQR Area Forecast Discussion National Weather Service Portland OR 222 PM PDT Sun Jul 13 2025 .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...General area of high pressure over the Pacific. Satellite shows upwelling along the coast promoting a mixture of LIFR CIGs and VIS, and VFR conditions. Overnight, conditions will degrade over the coastal runways. Will see variable conditions though before they completely settle so airports right near the coastline will see equal chances of IFR and VFR. Elsewhere, VFR conditions persist over the next 24 hours. After 15Z Monday a shortwave trough will move over the region. There is around a 40-50% chance of MVFR CIGs along the Columbia River seeping into the northern Willamette Valley and the greater Portland/Vancouver-Metro runways. If they do form, will see CIGs around FL015-FL025. As daytime temperatures rise, clouds will lift and clear around 18Z Monday. PDX AND APPROACHES...VFR conditions persist through the TAF period. Expect northerly to northeasterly surface winds less than 10 kts with wind gusts aloft between FL015-FL025 up to 25 kt. These winds will likely mix down to the surface this afternoon. There is around a 50% chance of gusts up to 25 kt. Overnight there is a 40% chance that MVFR CIGs will develop. However, given the depth of dry air it will be difficult to form. If it does it would be for a short period of time. -Muessle && .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. Extreme Heat Watch from Tuesday afternoon through Wednesday evening for ORZ108>115-119>122. WA...Heat Advisory until 10 PM PDT this evening for WAZ204>207-209- 210. Extreme Heat Watch from Tuesday afternoon through Wednesday evening for WAZ204>207-209-210. PZ...Dense Fog Advisory until 2 PM PDT this afternoon for PZZ210- 251>253. Small Craft Advisory until 5 AM PDT Monday for PZZ251>253- 271>273. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland