884 FXUS66 KPQR 262057 AFDPQR Area Forecast Discussion National Weather Service Portland OR 157 PM PDT Sat Jul 26 2025 .SYNOPSIS...Benign onshore flow keeps temperatures near seasonal norms through this weekend. Temperatures trend warmer again during the first half of next week, with thunderstorms looking increasingly possible along the Cascades each afternoon and evening. && .SHORT TERM...Now through Sunday Night...Upper level troughing continues to progress eastward, coming more overhead across the PacNW today. Guidance initially suggested clouds clearing by this afternoon but low level clouds have stuck around longer across the region. This will likely stunt peak afternoon temperatures, toping out in the mid to upper 70s inland. Coastal areas and the Cascades are expected to reach the low 60s to low 70s. Conditions on Sunday will be similar, though model guidance is suggesting lower probabilities for cloud cover developing inland late tonight. Chances are 20-50% as of now but seem to be less coherent/homogeneous at this time. OVerall, Sunday is expected to be a few degrees warmer than today with highs topping out in the low 80s inland and mid 60s to low 70s along the coast and Cascades. -Batz .LONG TERM...Monday through Friday...Guidance continues to suggest temperatures rebound back into the upper 80s to low 90s Monday through Wednesday as ridging builds across the Great Basin and into the PacNW. Probabilities for inland valleys to reach 90 degrees on Monday are modest at 10-40% but increase significantly Tuesday and Wednesday to 50-80% for most locations. Although hotter temperatures are expected, a more significant heat event continues to look unlikely as the forecast envelope remains rather tightly clustered in the low 90s while HeatRisk largely remains in the minor category with a few patches of moderate in the interior valleys. This is underscored by NBM probabilistic guidance which continues to keep chances to reach 95 degrees near or under 20% for the most part. Guidance then suggests temperatures will begin to moderate back towards seasonal norms late in the week as the ridge axis begins to shift further east. A deepening upper level low is also likely to set up off the British Columbia coast, though there is disagreement among the models where exactly the center of the low sets up. Depending on where it sets up, south to southeast flow could set up across the PacNW or at least a portion of the area, bringing monsoonal moisture and potential for thunderstorms. Persistent southerly flow will help increase PWAT values to 1.0-1.2 inches east of the coast range. These values are 120-160% of normal for this time of year with the higher larger anomalies across the Cascades of Lane and Linn county. Disturbances embedded within the upper level flow will help support destabilization across central Oregon and to a lesser extend over the Cascade crest. For now, have introduced a 15-20% chance for the far eastern portions of Lane and Linn counties Monday and Tuesday evenings. Agreement and exact details become murkier into the middle of next week but the threat for thunderstorms along the crest remains. A stronger embedded shortwave is expected to move through the upper levels across northern California and Oregon which would bring better large-scale accent and possibly greater thunderstorm coverage Wednesday and Thursday evenings. Models also show potentially weak steering flow which could lead to slow storm motion and localized heavy rains. -Batz && .AVIATION...Onshore flow continues this afternoon with the marine stratus deck lifting and breaking up across the northern Willamette valley and north Oregon coast - conditions trending back to VFR. Expect these VFR conditions to persist into the evening before stratus redevelops along the coast 03-09z before pushing inland 12-15z. Thus, expect degraded conditions Sunday morning before VFR CIGs/VIS return Sunday afternoon. Expect fairly light winds through the forecast period, with gusts generally below 10-15 knots. PDX AND APPROACHES...This afternoon CIGs have lifted back to VFR with continued clearing skies into the evening hours. However, we`ll likely see the return of MVFR stratus come early Sunday morning before clearing occurs midday Sunday and VFR CIGs return - low to moderate confidence regarding the timing of the clearing. -Schuldt && .MARINE...Surface high pressure continues to reside across the coastal waters through the latter half of the weekend into next week facilitating rather benign conditions going forward. Expect winds to remain generally out of the north through at least the middle of the coming week although there may be a bit of a easterly component to the flow on Sunday. Tuesday onward these northerly winds will be a little breezier compared to Sunday/Monday with gusts in the 15-20 knot range during the afternoon and evenings. Fortunately, background swells remain unimpressive through the middle of next week as well, so given the aforementioned winds the likelihood for Small Craft advisory conditions are low. -Schuldt && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...None. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland