National Weather Service (2024)

Area Forecast Discussion
Issued by NWS Portland, OR

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-- Discussion containing changed information from previous version are highlighted. --459FXUS66 KPQR 262046AFDPQRArea Forecast DiscussionNational Weather Service Portland OR145 PM PDT Wed Jun 26 2024.SYNOPSIS...
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See Also
Technical Discussion: Brighter days to end the work week, turning humid & unsettled this weekend
Mother Nature not sure on pushing summer into our region,so she will give us alternating mix of warm summer days and coolershowery spring days. Lots of clouds around tonight into Thursday,along with a few showers as low pressure shifts inland. High pressurewill bring dry and bit warmer weather for Friday into Saturday. But,its back to clouds and some showers with seasonal temperatures forSunday into early next week. Dry and back to bit warmer weather asnext week progresses.
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(Tonight through Saturday)...Strong onshore flow across the region this afternoon, with abundantclouds and even a few light showers. Temperatures down compared topast few days, with 60s for most areas. Still will see a few lower70s in the Willamette Valley and into the Cascades prior to sunsettoday, but overall, rather pleasant for this time of the year.Southwest flow aloft will continue overnight into Thu, as broad lowpressure area sits offshore, centered just west of Vancouver Island.Meanwhile, a weak upper level disturbance off the south Oregon coastwill shift inland across southwest Oregon tonight. Add to the mix aweak front that extends from the low near Vancouver Island back tothe south roughly along long 127 (about 125 miles offshore). Togetherall these systems will provide ample lift, and with moisture inplace, will see scattered showers for just about anywhere for latethis afternoon into Thursday morning. Does appear best chance ofshowers will be focused over the higher terrain (Coast Range, WillapaHills, and the Cascades/foothills) as the weak front comes onshoreand across the region overnight. Even so, any rainfall will remain onthe lighter side, with 0.01" to 0.15" of rain, with 0.10" as much as0.25" in the higher terrain. That said, could see few spots in thecoast mtns and the Cascades (north of Santiam Pass) 0.25" to 0.50"with heavier prolonged showers.Not much change on Thursday, as will maintain moderate to strongonshore flow. As such, will be plenty of clouds in the morning, withclouds gradually breaking apart in the afternoon. Though showerpotential will be decreasing through the day, will maintain highchance of showers over the higher terrain.Once the upper trough shifts east of the Cascades, high pressure willbuild across the region. At same time, will see thermal trough overfar southwest Oregon strengthen. This will bring back a north tonorthwest flow in the lower to mid levels, which is a drying andwarming pattern. So, will see lot more sunshine across the region onFriday, as well as Saturday. Temperatures jump up well into the 60salong the coast, and 70s to near 80 across the interior. Suspect manyinland areas (from Portland/Vancouver metro southward through theWillamette Valley, and in the Gorge to Hood River Valley) will getback into the lower 80s on Friday, and again Saturday.But...changes arrive again, as another upper trough approaches. Willsee increasing onshore flow later Sat afternoon, with cloudsincreasing along the coast and over the Coast Range/Willapa Hills.Could even see a shower or two in those areas. /Rockey.LONG RANGE...Back to cooler temperatures and increased onshore flowas upper trough works its way inland over the Pac NW. Ensemblemembers suggest the potential for the return of scattered showers,40-60% for the coast and higher elevations and 15-35% for inlandvalleys according to the NBM. Again, amounts look very limited atthis time. Ensembles show bit more uncertainty in the pattern earlynext week, though in general the suggested patterns would bringcontinued mild weather. Temperatures look to remain in the 70s forinland valleys with mostly dry conditions, except for the potentialfor lingering scattered showers Monday. -HEC
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Strong onshore flow across the region this am, withwidespread VFR deck (mostly 4500 to 5000 ft), though still havepockets of MVFR CIGS along the coast. Clouds will continue togradually breaking apart through this evening.Air mass is slightly unstable, enough to get a few showers. Betterchance of showers overnight as weak front (about 125 sm offshore asof 3 pm) shifts inland overnight. Generally, will remain VFR withbroken decks from 3500 to 6000 ft tonight into Thu am.PDX AND APPROACHES...Onshore flow continues through Thu. VFR deckthis afternoon and overnight, with main deck at 4500 to 5000 ft. Willsee CIGS likely at 3500 to 4000 ft overnight and persist into Thu am.Will maintain a small chance (25% or less) for showers into thisevening, with better chance overnight. /Rockey
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Broad low pressure offshore will maintain south tosouthwest flow on the coastal waters, with winds mostly 10 to 15 kt.Seas staying in the 4 to 6 ft range.High pressure offshore will return a bit for Thu night through earlySat. At same time, will see thermal low pressure over far southwestOregon into northwest California. As such, will get back into somenortherly winds, with gusts 20 kt in afternoons/evenings.But, yet another low pressure arrives later Sat, with winds flippingback to the west or southwest. Gradients weaker, so winds notexpected above 15 kt. Seas stay in the 4 to 6 ft range.
-- End Changed Discussion --&&.PQR WATCHES/WARNINGS/ADVISORIES...OR...None.WA...None.PZ...None.&&$$www.weather.gov/portlandInteract with us via social media:www.facebook.com/NWSPortlandwww.twitter.com/NWSPortland