Bay Area storm: A deep dive into atmospheric river rolling through region and a preview of the next

let me show you why it would look so gray in that view this is live First Alert Doppler and this is going exactly according to the way we've been able to share this in the high resolution forecast in all of our first alert forecast over about the last 48 hours this storm has gone almost perfectly according to the way the forecast models had it depicted which means we've already seen some of the better rain coming into the North Bay let's just stop it right here and in the 1:00 hour you can make out the organized line there that's always a helpful thing to look at on radar like this cuz that's cold front and that's where you're going to notice some of the more impactful rain we've also got another element to it back here this is all going to move across the bay kind of like an organized line and we can take it from where we are now put it into the future cast sees that line and progresses it across the bay within it there's a narrow region right at the edge of the cold front where rainfall intensity is going to pick up and that's also going to be where the wind is going to be the most intense so it's helpful to watch this and pick out that line and as we go through the 4:00 hour you can really see it beautifully on here as it traces its way once again through Marin towards the Golden Gate it gets right over the heart of the Golden Gate by the time we get into the main commute hours of this morning and the timing on this might just be a little slow in in terms of the forecast in other words has it coming through here at 6:00 we shouldn't rule out the possibility it's doing that at 5:00 or maybe even 4:30 the general takeaway would be right through that late afternoon early evening not the best time and unfortunately this going to be unavoidable for a lot of people who just have no other choice and have to be on the road at that point if you don't have to be on the road through this point in the day that'd be one of the better times to just avoid it with pretty widespread steady heavy rain moving across the city Peninsula East Bay and then it gets down to Santa Clair Valley so this is why I was saying for San Jose it's going to be a little while before you really get into the best part of the system that is in the 7:00 hour and we can trace that line through conquered and right down into San Jose and it'll be there through the evening it's still there still looking at pretty good widespread rain going through the 9 10 11:00 hours but this is effectively the the end of one phase of this storm that's when we're going to see that most impressive line of widespread steady heavy rain in general clear the bay and then we're going to enter the second phase of rain which is going to be kind of a different nature to this is going to be on again off again showers the potential for isolated thunderstorms which are going to show up here here comes a crop right there and you can see those will stay with us throughout all of Thursday we're now into Thursday evening and we still have that uh the ingredients are there for occasional isolated thunderstorms even into Friday we're now at Friday in the early afternoon and that hasn't changed so for to solid today is Thursday and Friday the rain is going to be a lot more manageable however you could be one of the locations that gets one of those brief little cells that moves over your part of the bay and it's impossible to say exactly where one of those or when one of those will occur but the takeaway from what we just saw on that depiction is they they'll be out there you're going to get plenty of breaks of blue sky on both Thursday and Friday they're actually going to be real pretty looking days it's going to be a great Cloud show and then every once in a while the sky will go dark you'll get a brief downpour of rain it'll move out that does not appear to be a major concern from the rainfall standpoint from this system instead it's now through about 10:00 tonight when the majority of the rain's going to fall so let's take a look at that from a couple of different ways it's enough rain that the national weather service has us under a flood watch until Friday and that has to do with the fact that it's going to take some time for this evening's rain to work through the watersheds particularly in the north bay where those streams and Creeks are going to rise uh this also does include for the rest of today the possibility for flooding on roadways which is why we've got Alex Montano driving around Marin right now looking for those ponding of waters on roadways and and puddles and um the other aspect from it though besides the roadways would be the streams and creeks in the North Bay the ground's already saturated up here so you just want to take one minute here to show you one of the more detailed forecasts for how a storm like this would impact those watersheds the most notorious one is the Russian River that's the biggest Watershed here through the North Bay and this is the one that will often draw the most attention if it approaches its banks cuz it's carrying a big load of water there's some good news on this one we often look at it as it goes through that Canyon and gerville sits right on the edge there and would be the most impacted should this be a scenario where the Russian River approaches its banks the way to read what we're seeing here watch the wavy black line that black line on there is specific to what we would call the deterministic forecast in in other words that's the most likely outcome for the level of the river in relation to flooding that we expect and you can see the times going along the bottom here take a look at Friday at midnight and you can see that line goes here so let's go back to right about midday Thursday when the river most likely is going to Crest so you can see how there's some time we're getting the bulk of the rain tonight the Russian River doesn't hit its highest point until probably tomorrow midday now all the other colors on here show you what the range of possibilities are so it's possible anywhere in this light blue and there's a whole bunch of fine print over here but the light blue over there is essentially telling you hey there's a 20% chance you could get into that range and that 20% chance of rain range from the level of the river does include the Russian River getting to monitor stage and then maybe even flood stage so it's a 25% chance meaning there's a 75% chance it's not going to do that so there's good news on that front but we're going to watch that very closely um the Russian River did cause some problems with the storm cycle from about a week ago um and that Rose fairly quickly so we'll watch it rainfall total still look like this still to go between now and this is taking us from now through Friday morning so this doesn't include the isolated showers that'll still come in um throughout Friday afternoon but you've still got another inch and a half to go from this point on in the north bay and you can see the numbers for everybody else and when we take a look at the South Bay and play that forward from now into Friday uh we're going to get about an inch of rain in the city and about an inch or so San Jose you're going to get about an inch of rain out of this which is uh that's good rain for you that's more than you would typically get but that would you wouldn't be any different in terms of a roadway standpoint that'd be the primary concern there obviously maybe some ponding of water on roadways from that so in case you'd heard yeah this is an atmospheric River and it does fall in the scale here of probably being a weak to moderate one and because the term gets thrown around a lot yes technically you could call this a Pineapple Express and the only thing that is telling you you can see here is where we are and you see the higher concentrations of water vapor this is right now going into Wednesday at 2 o'clock right when the storm's coming on Shore that moisture source is coming from the general direction of Hawaii so in that case yes we do call this a Pineapple Express but the much more important thing about these is the recent awareness of ranking them on a scale recognizing their characteristics and fully understanding their impacts we called them a Al expressed back in the 80s and '90s before we fully understood these things there is a whole range of knowledge now about atmospheric rivers that we didn't have so the far more important takeaway when it comes to classifying these things and labeling them is the scale they go from one to five five would be very problematic one would be weak a two is moderate and sometimes even brings beneficial rain unless it's falling on a landscape that is already saturated because you you've had several storms come through that have already saturated the ground then you have to consider that to be more like a two or a three because when you rank them on a scale you are taking into consideration what the preceding conditions of the landscape are on which it's going to fall and that's why this one gets a little bit more of an upgrade on the scale so this is kind of like a two to a three because of everything we looked at in terms of flooding and one other aspect that we haven't discussed on this storm yet which might be the most impactful part of this one and that's going to be the wind and wind is a big part of atmospheric Rivers these things are funneled in on atmospheric conveyor belts they're not only pulling all the moisture up from the subtropics but they're pulling them along on very fast winds and when those winds interact with local topography it's a whole other aspect to the kinds of storms that are fueled by these things and wind is one of the considerations that go into ranking these so if you take a look at I know the the there's fine print on here but since this term atmospheric river is such a buzz term and it gets so used and it's almost in some circles it's almost become um it's almost become a bit of a joke because it gets a little overused and that downplays the crucial importance of of of recognizing and labeling them it's worth it just to go a little bit deeper for a moment especially on a day when we have one coming on Shore and maybe we've got more eyeballs and more attention on it this is actually the image that was put together by scrips Institute of oceanography in San Diego they are the that has really revolutionized our understanding of these things and that's where the scale actually came from so we're looking at a map of the West Coast over here you see that big Green Dot so that's telling you that the forecast we're looking at over there is specific to where that dot is and I've set this at San Francisco's latitude so that's what we're concerned about you can see the scale on here see where it's there are red dots up here if you can see it that's where this was a far more significant atmospheric River when it came into Portland they got much bigger rain and they got stronger wind down here on the bay we're running right on the verge before this thing goes into blue so let's talk about the colors yeah if you guys are zooming in on that for a moment I don't know how well you can see that but it's a helpful tool to look at to really kind of see how these things impact the coastline in general but beyond just looking at the dots I've got a scale over here which will kind of break that down and explain San Francisco's experience or the forecast for what we're going to experience remember this is specific to San Francisco the time's going along the bottom this is right now that gets us to Wednesday at 2:00 and the line up here shows you how far into that scale on the atmospheric River you're going and there's a bunch of numbers over here the numbers we're not going to go into the detail on but the scale corresponds to you know if you get to 500 on there that's category one if you get to 750 that's a category two but they colorcoded it for us so we don't have to memorize that look at the green down there this is a category two all right that's just a little bit deeper in the Weeds on atmospheric Rivers I'm guessing if you're here with us on the Stream you're interested in these kinds of things and it's worth going into a little more detail on them because it's such an important nuance and Atmospheric River often times is too generalized and the term Pineapple Express really doesn't help us a whole lot or do a lot of Justice to help with storms although it can tell you sometimes that the storm's going to be a little warmer all right on to the most important aspect from this storm and that's going to be the wind aspect of it so if we come in for a close-up look as this system arrives the Deep shades of purple on here sh you where you've got wind speeds getting up to around 50 miles an hour most of that is staying out over the water notice what happens as soon as you hit land a lot of the friction takes over and you don't get the great intensity of the wind out over the ocean unless you are right on the front lines the coastal ranges which are perfectly oriented to on the on the first part of this to be right on the front lines where those 50 mph winds and then because they're elevated they're kind of like a buffer where they're going to get hit hard hardest they're going to absorb most of the energy and spare most of the rest of the Bay from the worst of that wind but because of the way the storm is oriented and watch that big band of purple will time it out through the afternoon and into the evening that gets us through about six 7 o'clock before the worst of that wind has passed let's bring it back to right about um peak wind this is right about a quarter to four today so you've got this big band of purple sitting right off the coast I've highlighted the spots along the coast on here which are on those front lines since Beach halfon Bay and keep in mind those are lower elevations you get higher and the wind impact is going to be a little more intense and that's you can kind of see the winds getting absorbed right here through the hills on the peninsula and through Marin and one other place it's kind of subtle but there's a purple splotch right there in the East Bay Hills another vulnerable spot and when we look at this differently again these are the areas where the national weather service has put out a high wind warm morning so wherever you are in the bay today you are under a wind advisory this is a high wind warning specific to the coast and the terms definitely I think relay the degree of concern if you've got an adviser that's the National Weather Service saying heads up going to be windy enough out there you might get some flying debris you could have some issues be aware stay cautious if you fall in an area that has a high wind warning on it that's their attempt at saying take this seriously this could be the kind of wind that does some pretty good damage and the two areas of concern for this would be down trees and then the widespread power outages that those down trees are likely going to cause we're just getting into the time a day now where that's going to become the bigger Focus so we've already we showed you pictures of the down tree from Santa Clair County earlier but it's really going to be these areas in red which should be on guard for the potential for a little bit more of that to occur between about now and say 6:00 and I just wanted to skip over to the East Bay Hills to point that out shouldn't be as widespread here but the other part about the concern for down trees now and we probably can't State this one often enough it's not necessarily entirely the intensity of this particular storm or any particular storm at this point it's the fact that we went through a significant drought between the years of 2016 and 2017 which stressed a lot of our trees and we're still waiting for the every time one of these storms comes through we see a higher occurrence of trees going down um since that drought so that's a concern in the East Bay Hills people have done a lot of work here we've we've done in-depth stories here on CBS News Bay Area about the East Bay getting proactive on that very issue in the awareness that there's a big vulnerability here to tree so on the one good news a lot of work has been done here but in those rural spots out along the peninsul and the Santa Cruz mountains you can't get in um and it it's all different entities and there's probably a little more vulnerability there okay that covers everything from the Sunday storm there's another one coming uh that that was Wednesday actually I should say that covers everything from the Wednesday storm I got ahead of myself there's another one coming on Sunday so here's what that one looks like we're going to get some time here there's a bit of a breather Thursday and Friday even though we don't turn the rain off completely it'll be isolated scattered occasional showers with maybe a thunderstorm or so Thursday and Friday really are break days and so will Saturday be to a degree before this next system gets here that's Sunday looking right in the middle of the day 3 in the afternoon and this one has been um a bit squirly in the forecast models in terms of its location it's been adjusting almost daily and the trend on that has been to adjust it with more of a direct locator on us in terms of rain and perhaps wind it's probably going to be a big rainfall story for Southern California as well but it's also going to do it's also going to do a number here from a rainfall standpoint because that's a pretty Direct Hit for us in terms of rain and perhaps more importantly from that one wind so just a quick look ahead to this Sunday storm in two ways how much rain could we potentially get from the Sunday storm here that one adds up to about perhaps an inch and a half maybe close to 2 Ines of rain in general Bay Area Wide and it looks like this will that will probably be comparable to what we're seeing from this one maybe a little less but let's give that one a little more time to play out rainfall totals are actually going to be bigger from like Santa Barbara County down to LA from that one and more prolonged just from a regional scale in terms of what this Sunday Storm's going to do it really does look like it's not just Sunday for them it'll the center of the storm will get down there Sunday and then it'll hang out into Monday and Tuesday and it will have an atmospheric River pulled into it it could be significant ific rain in Southern California but it's going to be important enough here at home from a rainfall standpoint as well and potentially and perhaps even more interestingly for this Sunday Storm from a wind standpoint and I'll show you what I mean by that as the storm develops we're just looking at the Windfield and now we see the same occurrence of what we've got today which is perhaps one of the bigger concerns about today's storm these strong winds developing around the coast this one does it again only with more intensity from where the forecast stands at this point because of the location of the storm and you can see the center of the low is now sitting right out here and now in this long range forecast which is what we're looking at which means the resolution isn't as high so you don't see as much detail in this forecast as we did for today's and you also have to go along with the caveat that here we are it's Wednesday afternoon we're looking at Sunday on a storm that has already changed its location and timing a little bit over the last few days some of this can still change there's still a little bit of time for this to change but for where things stand now on this forecast it's worth messaging Sunday storm could be a significant wind event here and you see the bright colors are purple sitting right off the coast if we've got 50 mph gust now at their strongest this could match that or even exceed it a little bit by the time we get to Sunday and it goes from Sunday afternoon into the evening so second half of the weekend um that will be a factor from that storm so going to be busy around here we know that we've got our first alert status on here for Wednesday Thursday and Friday and we'll probably also have it for Sunday as we get closer to the arrival of that next system we'll just leave it on that image for now with everything going on for today just a just a note to be thinking ahead because Sunday storm could also be pretty impactful we'll be covering this throughout the afternoon of course we've got our whole list of newscasts that'll start at 3 in the afternoon 3:00 5 6 7 8 9 11 we're going to be live through all of them you can find us on the stream which you clearly have already done here uh but you can also find us uh over the air or any other way you'd like to watch us because all those newscasts will be available there as well and we'll check in as well here if anything um of importance breaks through that we want to make sure you know about on this we'll have updates here as well in the meantime thanks for checking in with us and we'll leave you with a live shot in Marin by the way this is Alex Montana who's been out driving around for us and he's still on 101 here and it appears like he's gotten pretty far north at this point you kind of recognize where things have opened up a bit if you know this drive and he's driving into that heavier band of rain that we were looking at on first ear Doppler where you've got those brighter bands of yellow and orange so it's a great example of what that looks like when you when you're driving through it this is probably like a typical scene here for what's about to play out for those of us who are not in Marine in over the course of about the next 6 hours and just I mean look at the water flying off the backs of the tires here you can tell that the water has come down in heavy enough amounts as it continues to rain that's the kind of stuff that I mean on the one hand it reduces your visibility and then on the other hand um you know the puddles he's hitting right now are not too overwhelming but when we talk about ponding of water on roadways uh that's Pro for the overwhelming majority of us who are just doing a commute on well-maintained freeways it's that ponding of water on roadways that probably has the biggest impact and can cause accidents all right we'll keep monitoring this and we'll have updates for you right here throughout the afternoon thanks for checking in with us

Channel: KPIX | CBS NEWS BAY AREA

Views: 38,222

Keywords: Weather, Bay Area weather, Darren Peck, Atmospheric River Storm, Storm, Flooding, San Francisco, CBS News Bay Area, KPIX

Id: lT9Hnpsvc3s

Length: 20min 41sec (1241 seconds)

Published: Wed Jan 31 2024