National Weather Service Area Forecast Discussion for Seaside, OR USA
000 fxus66 kpqr 292214 afdpqr Area Forecast Discussion National Weather Service Portland, OR or 314 pm pdt sat apr 29 2017 .synopsis...low pressure moving into british columbia will bring a frontal system through the region tonight. light rain will spread into the north coastal areas later this afternoon, then across the area tonight. there will be post-cold frontal showers early sunday, with showers decreasing through the day. another weak system will likely bring light rain monday into monday night. higher pressure will bring dry and much warmer weather to the area during the mid week period, though a warm front might get close to brushing the far north coast tuesday. an upper level trough is modeled to approach the pac nw late thursday into fri and may linger into the weekend. this will bring increasing precip chances and cooler weather. && .short term...tonight through tuesday...conditions are dry across most of the region this afternoon as an upper level ridge resides over the pac nw. however, the ridge axis is now east of the cascades and high clouds are increasing ahead of the next approaching frontal system. this frontal system is associated with occluding low pres moving toward haida gwai today. the leading warm front will spread light rain onto the south wa and far north or coast later through the late afternoon, with rain spreading inland this evening. the cold front will move through the region overnight. overall rainfall amounts through the overnight period will not be all that impressive, with less than 0.25 inch over the interior lowlands. the coast and higher terrain of the coast range and cascades should generally be in the 0.25-0.5 inch range with locally higher amounts possible. there will be some post-frontal showers around sunday. there is not much cold air aloft moving in behind this front, so instability will be limited and showers should be pretty weak. the best showers should be in the morning, with decreasing activity in the afternoon. the airmass will be cooler, with 850 temps modeled to drop back below 0c. this should limit high temps in the upper 50s for the lowlands. there will be a break later sun into early mon. then the fcst models in decent agreement that another weak low will form offshore along the stalled baroclinic zone from tonight`s system, bringing the front back north as a warm front during the day mon. expect rain chances to increase mon afternoon and mon night. the system is weak enough that confidence is not all that high that all locations will see measurable rainfall. the ne pac upper level ridge will strengthen significantly over the pac nw on tue. this should mean mainly dry conditions tue, with much warmer temps. highs over the interior lowlands will likely reach into the mid to upper 60s. there is a slight chance that a weak warm front will brush the far northern coastal zones with some light rain later tue. pyle .long term...tuesday night through saturday...the fairly strong upper level ridge is expected to remain over the region through wed. the model 850mb temps warm considerably wed, suggesting high temps well into the 70s are likely for the interior lowlands. the ridge axis shifts further east into the interior nw thu, which allows a fairly deep trough to approach the coast later thu and fri. the fcst models bring increasing precip chances thu afternoon, will the potential for some thunderstorm activity. highs on thu expected to remain several degrees above normal. precip chances continue fri and sat as the trough shifts directly over the region, with temps cooling off considerably. pyle && .aviation...high pressure over the pacific northwest will bring vfr conditions through early this evening. however, an incoming front will bring a period of rain and lowering cigs overnight. a mix of mvfr and ifr conditions appear likely to develop along the coast between 00-06z sunday and mvfr restrictions should become fairly widespread inland between 06-12z sunday. kpdx and approaches...high pressure over the pacific northwest will bring vfr conditions through this evening. however, an incoming front will bring a period of rain and lowering cigs overnight with mvfr restrictions likely to develop between 06-12z sunday. /neuman && .marine...a front dropping southeastward will bring small craft advisory level wind gusts of 25 to 30 kt to the waters late this afternoon and evening. the central oregon waters may have a hard time reaching these thresholds, but will keep the advisory going for now given they could still see a couple hours of 21 to 25 kt gusts, but it admittedly looks marginal at best. high pressure will then shift back over the waters sunday and monday and bring more quiet weather. after a weak front skirts the waters late monday or early tuesday, a summer-like northerly wind pattern should develop for a couple days towards the middle of next week. a westerly swell approaching 10 ft may impact the waters late in the week, but confidence in this scenario is low. /neuman && .pqr watches/warnings/advisories... or...none. wa...none. pz...small craft advisory for winds until 1 am pdt sunday for coastal waters from cape shoalwater wa to cascade head or out 60 nm. small craft advisory for winds until 1 am pdt sunday for coastal waters from cascade head or to florence or out 60 nm. && $$ interact with us via social media: www.facebook.com/nwsportland www.twitter.com/nwsportland this discussion is for northwest oregon and southwest washington from the cascade crest to 60 nautical miles offshore. the area is commonly referred to as the forecast area.
Information courtesy of the National Weather Service - NWS Portland...
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