Category 4 Atmospheric River hits Pacific Northwest

hey everybody michael snyder pacific northwest weather watch today is february 28th the final day of february 2022 and today we're going to take a look at this atmospheric river causing all kinds of problems for the pacific northwest you can see the apparent low pressure guiding this system into the pacific northwest we've got that high pressure over the great basin here and this gradient here is what's bringing this atmospheric river into the area you can see the lightning activity going down through the inter tropical convergence zone to our south you see a few lightning strikes also in the parent low back here in the colder air behind the atmospheric river as it moves into the area so just diving into things here a lot of things to cover you can see the pacific northwest is where the action is at today we've got all kinds of stuff going on we've got avalanche warnings winter weather advisories flooding high wind warnings wind advisories here we are looking at the day one excessive rainfall outlook and i don't remember ever seeing a moderate risk here for western washington but we have it today and if you take a look we have slight for most of the cascades of washington all the way out to the washington oregon coast and some of the terrain even olympia south of i-5 corridor and looking at south cascades willapa hills and the oregon coastal range here there is moderate risk here for rainfall exceeding flash flood guidance within 25 miles of a point so you can see moderate has at least 40 percent chance if you're in the higher terrain here heads up because landslide conditions are going to be prevalent in these areas extreme river rises small stream flooding streams that you might not think would could be a danger can rise rapidly and inundate homes uh so heads up for that you can see this atmospheric river is even targeting portions of the idaho panhandle out here too so we'll look at this in some more detail coming up but along the coastal regions there's a high wind warning up into washington all the way down the oregon coast gusts to 60 miles per hour watch out for the chaotic surf if you're out storm watching and again if you're along the coastal range highway 101 washington or oregon watch out because landslides could occur at any time really that steep terrain and this extreme precipitation coming into the area checking out the avalanche warning for washington state the cascades extreme avalanche conditions we're going to look into that a little bit more but i can't overstate just how dangerous the avalanche conditions are for the higher terrain you can see we have high wind warnings and advisories flood watches for much the puget sound there's active flood warnings going on so watch your local rivers pay attention to your local warnings eastern washington similar thing too you've got the idol panhandle and montana there with the avalanche warning you've got winter weather advisories and you do have some flooding concerns down there for the blue mountains and of course watch the runoff from the cascades and there are some gusty winds expected down there for portions of in northeast oregon too down into southern washington off into missoula montana they've got the high wind warnings out there over the rockies so heads up for that and pay attention if you're traveling eastbound on i-90 if you can even make it out of seattle i know i-90 is closed right now i know stevens pass is close as well to the high avalanche danger but here's what i'm talking about on the national weather service actually this is the northwest avalanche center uh the bottom line widespread avalanche is large enough to bury and kill you are expected at so quantity pass on monday they do not mince words on this site so avalanche danger is as high as it gets folks and go to this site if you're going out there if you must do it check this site out because they've got a lot of good information on here they take active pictures and they talk about the snowpack and different snow densities so very helpful information there and heads up on that avalanche warning and they've got avalanche warnings in effect for areas out here in idaho so this is the idaho panhandle avalanche center if you've got interest out here on intel montana make sure to check this site out and check this out all sudden with this atmospheric river we are into back into potential landslide issues for portions mainly seattle south you can see this is seattle tacoma and tacoma narrows here are already to the right side of this line with still some really heavy precip moving in and this just mentions that once you get to the right side of this red line here this means you are in landslide potential at this point and you can see here rain intensity duration threshold c-tac is just going to the right of this that is no bueno for seatac that's going to include places like west seattle down through normandy park des moines all the way down to tacoma as you can see tacoma narrows is to the right of that and you can see everett is more rain shadows they don't have to deal with that threat as much you can see seattle boeing field just below the threshold there so generally seattle north you're doing much better as far as landslide concerns here's the rate fall intensity duration index and you can see tacoma narrows in seattle tacoma have really jumped above that and even boeing field is above the threshold there too so there is the chance for some landslides through metropolitan areas of course on the steeper slopes is where those would occur so here's what's going on we've got this big trough out here in this stronger high with this tight gradient just funneling this moisture into the pacific northwest put this in a motion here and you can see that trough finally breaks down and then moves through the area and the precip should really cut off by thursday but we got a ways to go before that gets here and some pretty heavy precepts still going on today and here is the biggest baddest atmospheric river on the planet direct uh tap down to the subtropics even south of hawaii put this into motion you can see that really moist air just overtake the region there and then kind of slide down the oregon coast and then retreat back north a little bit and continue the precip though not as heavy as we get into wednesday portions of western washington and oregon as you can see this atmosphere river is lost with punch it's much more narrow at this point and slides down through california has a much weaker system checking out the winds here let's take a look at what's coming up here because you can see pretty windy on the oregon coast this morning going into early morning early afternoon that's when the high wind warning is in effect for southwest washington coast and you can see this really strong winds really buffeting the oregon coast for a while now this has been going on since last night at least and it's going to continue as finally the front kind of or the at least the wind passes through there and the next system starts moving in to vancouver island as it's really rapidly dying at this point so the winds are going to die around the region as then we turn dry or onto the extended so here's some precip totals that we're expecting on top of everything that we've gotten already actually let's start it off let's go to the morning here this is about eight nine ten this is about where we are right here nine o'clock and then so we can add on from there and you can see just that bullseye aimed at western washington oregon and you can see why they put that moderate risk out there for portions of southwest washington oregon coastal range southern cascades and the southwest flank of the olympics is a little more used to this type of just brutal heavy precipitation so it's probably why it really didn't get the warning because they're going to get as high as totals as really as anybody else through this system and then finally you can see the back edge of that approaching here as we go on into thursday but the total should really taper off as we get into tomorrow morning that's you'll you'll notice the precept starts to taper off through western washington a great deal here's the gfs just kind of comparing here and you can see similar bullseyes for western washington and oregon and this brings some precip all the way down to northern california there that atmospheric river slides is a much weaker system down through southern california here's the nam3 cam some high resolution action here check out some of the higher terrain this really picks up like areas near mount rainier and some of the south cascade higher terrain and the coastal range you can see here look at this it's talking about i mean we're all this is only 24 hours in and they're talking about totals up over 18 inches i don't know if this is accurate but it just kind of highlights the extreme nature of this event this is a category 4 atmospheric river so here you can see this this is what causes these atmospheric rivers we get these really strong ridges over the great basin here then you get a trough out here and just kind of a steering flow prolonged flow on the strong gradient as it brings us really deep rich subtropical moisture over the area very high freezing levels too so the snowmelt will add to any runoff that's going on with these with all this extreme rainfall now looking off into the extended a bit here here is last night's european run so we see that trough and ridge causing our atmospheric river and finally that trough dies and moves through and then kind of sharpens up and moves down the west coast and you can see some of these systems still brushing us as we go into the future here so this mor or last night's run looks a little bit more favorable if you like some active weather for the pacific northwest and you can see just how fickle this ridge positioning is if this ridge is a little bit further east these systems don't get in and hit western washington and western oregon and british columbia but if they back up just enough this troughing can carve out some interesting weather for our region here and then you can see systems riding back on the east side of this ridge as troughs continue to redevelop so confidence is low at this point because as you as we noticed yesterday we had more of a dominant ridge and it kept these systems out of the area so we're it's going to take a day or two before we start trying to lock on what's going to happen here in the extended as these ridge positions mean everything as far as these systems getting into the area here and let's go ahead and check out the gfs this is the zero 6z run and you can see the ridging the troughing the atmospheric rivers it finally gets out of the region there as the trough moves through and then the trough kind of hangs out and digs sharply over the southwest might bring some severe weather out over the plains into the southeast usa on into next weekend we'll see how that goes you see the gfs building this ridge and keeping the west coast troughing going on but generally would keep the pacific northwest out of this but then it starts to retrograde a bit on into the extended so there is some agreement that maybe this trough will start to you know dig on the back side of the ridge so we'll have to watch that but yesterday it looked like that ridge was going to take up shop a little bit better and keep the systems a little bit further east but so it's something to watch something to look for but we're getting out to la la land and we've got a lot of time to look at that stuff so here is the mountain pass in winter travel you can see they've got steven's passes closed let me just hit refresh on this make sure nothing changed both directions steven's pass is closed no estimated time for reopening so quality pass no estimated time for reopening close both directions extreme avalanche danger you wouldn't want to be out on the freeway and still call me pass some of those really steep slopes go right up to i-90 there but yeah so that that's something to look forward to in the future there too we'll watch this ridge and see if it brings some more active weather as we go into um mid-march um yeah so today's last day of february we're going into march now and we're these rainfall events get much more rare as we go through the year here and it's pretty rare to get an atmospheric river this strong in late february but it does happen once in a while but our big precipitation events are really going downhill so the chances of this another atmospheric river coming through the area at this point are very low so maybe we can fill the reservoirs and maybe we won't suffer too many landslide problems and avalanche dangers but we will check out the extended again as always tomorrow and we will see where we stand as far as land slides can stern avalanche danger and we'll see how the system is developing we'll take a look extended and i hope you guys are having a good day enjoy that rainfall and if you're in one of those rain shadowed areas then drive south towards seattle down towards portland okay i'll talk to you guys tomorrow

Channel: Pacific Northwest Weather Watch

Views: 5,397

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Id: g9qsAlhye1M

Length: 12min 32sec (752 seconds)

Published: Mon Feb 28 2022