National Weather Service Area Forecast Discussion for Long Beach, WA USA
000 fxus66 kpqr 191146 afdpqr Area Forecast Discussion National Weather Service Portland, OR or 346 am pst sun feb 19 2017 .synopsis...an active weather pattern will bring periods of rain and mountain snow to southwest washington and northwest oregon through much of this week. an occluded front was moving through southwest washington and northwest oregon early this morning, followed by showers and isolated thunderstorms associated with the parent low that is off the coast. the next low will move in from the southwest for more rain later tonight and monday. another low will follow shortly behind it later monday night and tuesday for more rain and mountain snow. snow levels will be below the cascade passes through monday morning with the higher elevations of the coast range possibly having a couple of inches of snow early sunday morning, then briefly rise monday before falling again through the rest of the week. gusty winds are expected for the coast today with possibly stronger winds monday afternoon. snow levels will lower into at least the cascade foothills and the coastal mountains during the middle of next week and beyond, but with limited moisture. && .short term...today through tuesday...a longwave upper trough is expected to remain off the coast between around 130w to 140w for the next few days as a series of weather systems moves through the pacific northwest. the first was an occluded front that was moving through northwest oregon and southwest washington overnight and early this morning. a trailing showery air mass will be over the forecast area today with a few thunderstorms as well. we have seen lightning already over the coastal waters and near florence early this morning. as a result, some of the showers could have small hail as well today. snow levels will be below the cascade passes today, but the only area that looks to get advisory type snow amounts will probably be just the south washington cascades. may see a little dusting of snow in the higher elevations of the coast range and in the cascade foothills as well today. this will be followed by another low approaching the forecast area from the southwest tonight, and moving through on monday. the models are still having a tough time coming into agreement on timing, intensity, and track of this low. nevertheless, there is a good chance of fairly strong winds along a good portion of the oregon coast monday, with a decent shot of rain and mountain snow. the snow level may rise a bit ahead of the low early monday but then drop back down to around the passes behind it later monday. there is a chance of reaching snow advisory amounts on monday in the south washington and the north oregon cascades, but probably not in the lane county cascades. the models show another low tracking through the area monday night and tuesday for more rain and mountain snow. these systems should finally begin adding a decent amount of snow again to our snow pack. tolleson .long term...no changes. previous discussion follows... tuesday night through saturday...upper-level trough sets up off the coast early next week, keeping the jet stream and the stream of tropical moisture south over california. this will lead to a drying trend across southwest washington and northwest oregon. though the bulk of the moisture will be to our south, weak shortwaves under the trough could generate a few showers through the end of this week. moisture will be limited, however, so not expecting any significant qpf. as the trough moves into the pacific northwest, snow levels will be falling, possibly below 1000 feet by thursday morning. with snow levels this low, can`t rule out a few flurries making it down to higher elevations near the valley floor, but again, moisture will be very limited so we will likely not see any snow make it down even near the valley floor. we will need to monitor next weekend or early the next week as we could see a system move in with this cooler airmass in place, leading to a period of mixed precipitation before transitioning to all rain. -mccoy && .aviation...a mix of vfr and mvfr across the forecast area early this morning as an occluded front moves across the area. showers have arrived at the coast and expect steadier rain inland to change over to showers by 13z. with the more unstable air mass vfr conditions should dominate but still may see mvfr cigs and/or vis with heavier showers. isolated thunderstorms are occurring near the coastline early this morning. thunderstorms are also possible inland later this morning through the afternoon. winds pick up out of the south starting this morning and could sees gusts as high as 30 kt along the coast and gusts in the 15 to 20 kt range inland. kpdx and approaches...light rain with occasional cigs around 2000 to 3000 ft through about 15z sun the trending toward vfr. there may be brief mvfr conditions with heavier showers today. also there is a small threat for thunderstorms in the area between 15z sun and 00z mon. /mh && .marine...initial occluded front moved northeast into the waters brought gale force wind to the central oregon coastal waters (pzz275/255.) buoy 46050 off newport had gale gusts for several hours and has begun to ease a bit as of 1 am. expect gales to lower to small craft southwesterly wind by 4 am and further ease in the late afternoon and evening. the parent 990 mb low associated with the front is about 230 nm west of newport at 1 am and will cross about 70 nm west of astoria this morning as it heads toward the north washington coast. this will likely bring gale force gusts to to the north oregon coastal waters (pzz250/255) through this morning. winds will turn southwesterly and decrease a bit behind the low this morning, but still expect solid small craft advisory winds to continue into this evening. there have been a few thunderstorms over the coastal waters overnight and may see more through this morning. the active weather pattern continues as another potentially strong low will affect the waters mon. there is still uncertainty on the strength and track of this system. there is definitely potential for gales over most of the waters. there is enough confidence to issue a gale watch for the central oregon waters (pzz275/255) for monday. seas are currently around 7 to 8 ft and will be rising today to the low teens this morning then into the mid teens by this afternoon or evening. the seas fcst for mon is tough, given the uncertainty in the surface low track. the stronger solutions would suggest seas approaching 20 ft are a possibility. will keep the fcst in the mid teens for now. pyle /mh && .pqr watches/warnings/advisories... or...none. wa...winter weather advisory until 7 pm pst this evening for south washington cascades. pz...gale warning until noon pst today for coastal waters from cape shoalwater wa to cascade head or out 60 nm. gale watch from monday morning through monday afternoon for coastal waters from cascade head or to florence or out 60 nm. gale warning until 4 am pst early this morning for coastal waters from cascade head or to florence or out 60 nm. small craft advisory for rough columbia river bar from 9 am this morning to 1 pm pst this afternoon. && $$ 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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