KPQR issues Area Forecast Discussion (AFD) valid 2024-05-31T22:34:00ZKPQR issues Area Forecast Discussion (AFD) valid 2024-05-31T22:34:00Z90%) of integrated vapor transport (IVT) exceeding 500 kg/m/s, with about a 50/50 chance of IVT exceeding 750 kg/m/s along the Oregon coast Sunday evening. Meanwhile the forecast area will be in or near the left-exit region of an unseasonably strong jet streak; this will enhance lift as the deepest moisture moves across the region. Deep moisture under the right circumstances can lead to unusually high rainfall rates. As such, Sunday afternoon and evening look quite wet for SW Washington and NW Oregon, with NBM probabilistic QPF suggesting the vast majority of the CWA has a better than 70-80% chance of receiving 1 inch or more of QPF. The same guidance suggests 1 inch or more of rain is a near certainty in the Coast Range and Cascades north of Highway 20, with NBM means suggesting 1.5-3.0 inches of QPF for the same area Sunday night into Monday. High-end (95th percentile) QPF suggest a couple locations could reach 4 inches of QPF if everything were to line up properly. With this in mind, it is not out of the question that there could be rapid rises or even minor flooding on a couple of our flashier creeks and drainages (the Grays River comes to mind), but based on latest guidance it appears the chances of this occurring at any given location are 10% or less. -DH/Weagle .LONG TERM...Monday through Friday...The unseasonably strong jet stream over the NE Pacific remains aimed toward the Pac NW through Tuesday, keeping the weather unsettled across SW Washington and NW Oregon. Latest NBM thunder probs are in the 10-20% range for much of the CWA Monday afternoon, which seems reasonable given the pocket of cool air aloft swinging through the region and the strong early June sun. Depending on how much sunshine can break through the clouds Monday, a couple of the thunderstorms could become strong enough to produce small hail and/or gusty winds. Either way, Monday will likely be somewhat blustery given the 30-40 kt SW winds at 850 mb shown by the 12z NAM. Guidance suggests another system potentially moving into the Pac NW Tuesday, though there is a lot of variability on the strength of this system. Starting midweek, models are suggesting a high likelihood of a strong upper level ridge of high pressure developing somewhere over the Western United States. Looking at the 00z WPC cluster analyses, there is still a lot of variability in where models and their ensembles are placing the upper ridge axis...which will be key in determining just how warm it will be toward the end of next week. Based on the 00z WPC clusters, it appears there is only about a 20-30% chance of a pattern that would avoid significant positive 500 mb height anomalies over WA/OR (i.e. significantly above-normal temperatures), with the remainder of guidance suggesting temps several degrees above normal (at least inland) by the end of the week. By next Friday, NBM probabilistic guidance suggests a 30-50% chance of highs reaching the 90s in the Willamette Valley, with a 5-15% chance of highs exceeding 100 degrees. With this in mind, those sensitive to heat should pay close attention to the forecast the next few days, and perhaps consider where they may go to stay cool late next week should the hotter forecast guidance prevail. -Weagle && .AVIATION...VFR conditions will continue into the evening and early overnight across the entire area. A Weak cold front will approach the area late tonight and will bring a chance for sub-VFR CIGs, mainly along the coast. HREF guidance indicates a 50-70% chance of MVFR CIGs developing along the coast around 12Z Saturday and persisting into at least the early afternoon. Northwest winds around 10 knots will continue before becoming light and variable overnight. Winds behind the from will be west/northwesterly between 5-10 knots beginning Saturday morning. PDX AND APPROACHES...VFR conditions through the entire TAF period. Winds will remain northwesterly around 5-10 knots. -Batz && .MARINE...Small Craft Advisory wind gusts up to 25 kt south of Cape Falcon (marine zones PZZ 272,273,252,253) will continue through the evening. A weakening Pacific front approaches the area tonight and will bring lighter west/southwest winds 10-12 knots on Saturday. A more organized and stronger storm system will move into the northeast Pacific Sunday shifting winds southerly. Small Craft Wind gusts are likely with 90+% chance of gusts exceeding 21 kts. There is also a 10-20% chance of a brief period of Gale Force winds of 35 kts for the latter half of Sunday. Seas will build to 8-10 feet at 10-12 seconds Sunday afternoon, persisting into Monday. Another westerly swell will enter the waters toward the middle of next week with seas of 10-12 feet at 14-16 seconds. -Batz && OR...None. WA...None. PZ...Small Craft Advisory until 11 PM PDT this evening for PZZ252-253- 272-273. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland www.twitter.com/NWSPortland ]]>