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Brian Lehrer: It's The Brian Lehrer Show on WNYC. Good morning again, everyone. I've lost track of how many rainy weekends we've had in a row, but I think it's been every weekend since first Ophelia hit us on September 23rd, and now there's at least one more ahead this weekend according to my weather app. We're curious, is there a seven-day weather pattern that has trapped us in this cycle? Is there a climate change connection?

For our climate story of the week, which we're doing every Tuesday, all this year on the show, we're going to try and get a handle on this now. We're joined by Andrew Kruczkiewicz, a research scientist, meteorologist, and expert in extreme weather and flooding at the International Research Institute for Climate and Society, which is part of Columbia University's Climate School, where they try to bring together social science, climate science, and public policy. Andrew, thanks for coming on for this. Welcome back to WNYC.

Andrew Kruczkiewicz: Thank you, Brian. Great to be here.

Brian Lehrer: We do seem to be in a seven-day weather pattern with clear skies on weekdays and rain on weekends, especially Fridays and Saturdays. Is that a pattern that happens in this area that maybe we don't notice when it rains on a series of Wednesdays or just bad luck?

Andrew Kruczkiewicz: There is ongoing research on these weather patterns and not only the link to climate change but just what makes the weather in the New York City area so special. There's not really, let's say a seven-day pattern per se. There are definitely times of the year where we tend to see these cycles, where we tend to see either one storm a week or two storms a week, but technically, I would say more in the fall and the spring, we are more likely to get stuck in these sorts of patterns. There are reasons for that as we transition between seasons, but yes, there's not really a climate connection with this. I think overall it's mostly just a little bit of bad luck.

Brian Lehrer: You and your colleagues at Columbia Climate School did predict a rainier fall, I see back in August. I guess you couldn't tell it all happened on the weekends, but was that based on El Nino, or what gave you that insight?

Andrew Kruczkiewicz: I'm glad you brought up El Nino and I'm mentioning our seasonal forecast. Yes, at Columbia University we do produce seasonal forecasts. Essentially what these are, are statements about how rainfall might deviate from normal in the coming few months. Back a few months ago, there was a signal for let's say higher than normal chance of rainfall to be above average for this season.

It doesn't necessarily mean it's going to rain every week or that we're going to see as much rain as we've seen. It also doesn't necessarily mean we're going to see devastating flash floods, which I think is a really important point here. Many times we have forecasts for above-average rainfall, but that doesn't necessarily mean we're also predicting floods. However, we do have predictions for floods in forecast for floods, and I think that is an important part of this discussion as well.

Brian Lehrer: Listeners, we can take your weather and climate questions for Andrew Kruczkiewicz, research scientist, meteorologist, and an expert in extreme weather and flooding at Columbia University's Climate School. 212-433-WNYC, 433-9692. Sure you can say if you're adapting to the rainy weekend pattern, we seem to have been in. Have you rescheduled your weekend outings?

Have you scheduled from some Tuesdays and Wednesdays off from work just so you could have what approximates a weekend? Have you noticed similar weekly weather patterns at any other time, whether they fall on Fridays, Saturdays, and Sundays or not? 212-433-WNYC, 212-433-9692. You said a minute ago that there doesn't seem to be a climate change connection with this seven-day cycle. How complicated is it to discern climate effects from simple weather effects that would be happening without the warming?

Andrew Kruczkiewicz: This is an ongoing area of research. There's a lot of research being done in this space. One of the areas is called attribution. How do we make statements around the degree to which climate change is actually influencing these extreme weather events? Really, in order to do that, when we're talking about extreme precipitation particularly and flash flooding, we must understand the ingredients that really make up the disaster or the impacts from these events.

I think it is challenging because there is-- Let's say in the past few years, the narrative has changed. Climate change is one of the first factors that has pointed to why we saw the devastating flash floods in Brooklyn and Queens both this year and also with Ida, but there's many other factors and it's important not to oversimplify those statements.

Now, the reason why we see socioeconomic impact from extreme events is really a combination of climate change-induced extreme rainfall, but also the infrastructure elements. The social elements which lead to certain populations, mostly underserved populations being more at risk. It's really important to talk about the interconnectivity of these different factors that make up a disaster

Brian Lehrer: On what we can see and how early we can see it, the Adams administration was severely criticized for not warning New Yorkers or making plans to close schools or anything else. On the night before that really bad Friday rainstorm that shut down a lot of public transportation and stranded people in other ways, were you as a meteorologist seeing that this was going to be something other than just another day of hard rain?

Andrew Kruczkiewicz: I think it's really important to listen to New Yorkers. What are the thresholds in the forecast that lead to some deviation in their activities for the next day? What are the messages in the warnings and watches that are issued by the National Weather Service, and also also propagated in the media as well? There is a lot of research done on developing these early warning systems, but we need a lot more work done on developing early action systems.

I think to answer your question more directly, yes, this was a situation where I saw the forecast and also saw the warnings and alerts being issued, but also very concerned about how people are going to interpret these warnings and alerts, who other people who are able to do anything different. We talk about availability of forecast and accessibility of forecast. That was clear, but who's able to take action? What are the resources needed for people to actually get out of harm's way or do something different? Stay home from work. These are things a certain type of person, certain type of New Yorker can do much easier than others.

Brian Lehrer: A listener with a sarcastic sense of humor writes to suggest that we all get our COVID or flu shots on the weekends since with the rain we won't miss much if we have a down day with the side effects. Ophelia, that does seem to have kicked off this cycle with its deluge of rain. That's the same Friday I was just talking about that overwhelmed so much of the infrastructure and then it came back a week later, less ferociously, but still really hard. Can we cite climate change as a contributor to the sheer amount of rain that these storms have brought?

Andrew Kruczkiewicz: One of the most direct, let's say, relationships between climate change and what we experience here in New York City in terms of weather is felt through extreme precipitation or intense precipitation. The models are pretty clear in that as the atmosphere warms, there is a greater capacity for the atmosphere to hold water and therefore the water builds up in the atmosphere and it's more likely to lead to these intense rainfall periods.

I do think if we're asking questions around longer-term trends in periods of intense precipitation, I'd say yes. That is a statement that we can make. We see that with tropical cyclones. We see that with-- Ophelia was a tropical cyclone going through extratropical transition, but we also see it with other types of precipitation such as frontal system-induced precipitation like we saw in the weeks following Ophelia. Yes, I do think that is a fair way to describe it.

Brian Lehrer: Listener writes, "Regarding repeating weather patterns. I was in college at School of Visual Arts in 2010 and that fall it would rain every Tuesday when I would want a bike to one of my classes. It went on seemingly for the whole season." Another listener writes, "Has climate change made it more difficult to forecast the weather? It seems like forecasts aren't as accurate as they once were." I don't know if you accept that premise, but there's that question.

Andrew Kruczkiewicz: I would be interested in the listener's perception of accuracy. One of the biggest challenges we face as scientists engaging with the general public or a certain sector is just the different ways that we perceive risk, different ways that we perceive accuracy or best types of forecasts. Most of my work as a scientist, I think most of the impact of my work is in that translation step. How do we tailor the forecast in an appropriate way? It's not easy. I think that's the answer I would say. How are we interpreting accuracy? I think in general, it's an interesting discussion I have with New Yorkers in general. What is an accurate forecast look like? The forecast on your phone, do you perceive it to be accurate?

Brian Lehrer: Jamie in Plainfield has a related question I think. Jamie on WNYC. Hello.

Jamie: Yes, I was just wondering if you thought it was because of climate change, some of these models seem to be off. I'm a dog walker, so I have to be very engaged with how the weather is. It just seems like being a weather freak that I am, it seems like some of the models seem to be off. Or, for instance, we seem to constantly miss the really heavy rain, when it may be predicted, and then it seems to go either to the west or to the east of us. It just seems odd to me, and that's only been for the last couple of years. I've been doing this for a long time.

Brian Lehrer: Thanks, Jamie. Good luck out there with the dogs.

Andrew Kruczkiewicz: Again, I think that it depends on a variety of factors. I think that forecasting extreme precipitation or these more intense precipitation periods has always been difficult. If the question is, because we're having more intense precipitation events, does that lead to, let's say, the perception of a forecast being less accurate? Perhaps that could be true. In terms of forecasting just average rainy days or our temperature, I'm not sure if that's changed so much on a shorter lead time on weather scale forecasts. In other words, like a day, or two days, or three days.

One thing I will say that has happened in the past few years is that many of us are checking our phone for the hour by hour forecasts. I find these influencing the way that we perceive accuracy. Even myself, I find myself looking at different hour-by-hour forecasts. We didn't really have access to that a few years ago. I think that is an interesting part of the equation in how we deem something accurate or not.

Brian Lehrer: Mary in Hackettstown, you're on WNYC. Hi, Mary.

Mary: Hi, Brian. Thank you. Can you hear me?

Brian Lehrer: I can hear you just fine.

Mary: Oh, thank you. I live in Northwest New Jersey. I have noticed in the past few years these enormous clouds, and today, there are just so many and they're dark, very dark, black almost. I lived in Monmouth County before and I never noticed that. I wondered if it's because I was so near the ocean.

Andrew Kruczkiewicz: Interesting.

Brian Lehrer: Will the clouds be different inland, Andrew?

Andrew Kruczkiewicz: Yes. Brian, I was going to see if your listener could maybe tweet a photo or somehow. I'm super keen to see what the clouds look like as a cloud fan. I think I could address the question either way. It sounds like perhaps you have some-- Well, this time of year, we don't really see too many cumulonimbus clouds. What you're describing sounds like that. Sussex County and other areas in Northwest New Jersey, very beautiful areas, very interesting topography.

Yes, the topography there is sufficient to create different patterns in the types of clouds that we see. We have air moving through, hitting the higher elevation rising and falling. Yes, I definitely think that your observation is accurate and rooted in meteorological theories, for sure.

Brian Lehrer: Thank you, Mary. We're in our climate story of the week, which we do every Tuesday. On the show today with Andrew Kruczkiewicz, a research scientist, meteorologist, and an expert in extreme weather and flooding at the International Research Institute for Climate and Society, part of Columbia University's Climate School, where they try to bring together social science, climate science, and public policy.

You told my producer a really interesting thing that I think a lot of listeners in our area might learn from if you lay it out a little bit, and that's that in a sense, we are the beneficiary, if that's the right word. Maybe it's the opposite, of many weather patterns because of where we are situated geographically. Maybe Mary was getting at a little piece of it being inland as opposed to on the coast within Jersey, but you were describing to my producer how influenced in the New York area generally by weather coming at us from various directions that might be different from a lot of other places. You want to go into it.

Andrew Kruczkiewicz: Yes, definitely. Growing up in the New York area is one of the things that really drew me to be a weather nerd. I think really what it was that drew me to this career. I think it's one of the most underappreciated parts of New York City, and I think it definitely adds to the dynamic nature of where we live.

In the wintertime, we all know that we see blizzards. We have heat waves. We have cold waves. We have the occasional tornado. We have tropical cyclones. We have tropical cyclones going through extratropical transition. We have different types of floods, which is something I'd like to touch on a bit more. We have coastal flooding, we have riverine flooding, we have flash flooding. I'm not trying to minimize that these are risks that lead to loss of livelihood, disruption in your life, for sure, but it is something that I think just adds to the experience of living in the New York area. I don't feel like we talked about it so much as much as it does influence our life, and it influences the culture here for sure.

Brian Lehrer: Nor'easters coming up the coast, thunderstorms generally propagate from the West, backdoor cold fronts that can arrive from the northeast. I guess the first time I really thought about it, what surprised me was the nor'easters. That something is coming from the south, up the East Coast, and hitting New York on that route, when generally the prevailing winds go from west to east, right? Generally, the winds go from west to east as the Earth rotates on its axis. How does the storm wind up coming up from the East and the Southeast?

Andrew Kruczkiewicz: Yes. There's a certain type of synoptic-scale setup when we see nor'easters. What I mean by that is just the upper levels of the atmosphere are set up in a certain way, where we actually have like a inverse tilting of the Jetstream, which leads to the storms actually coming from, as you said, the south and then sometimes more to the northwest or more to the north, but the term nor'easter really comes from the direction of winds.

When we have a storm coming up the coast, with the low-pressure systems spinning counterclockwise, we get a Northeastern flow into the New York City area and New England and the Northeast in general. That's where the term actually comes from. Not necessarily, because we're in the Northeast, it comes from the wind direction. Yes, that's why we see these very dynamic low-pressure systems in the wintertime as we all know. It's definitely something that I can remember for a very long time, my experience with these storms, and I'm sure a lot of listeners can as well.

Brian Lehrer: Since we talked about the accuracy of Columbia's seasonal forecasts that came out in August, for a wetter-than-normal fall, few listeners are writing in to ask any snow predictions for the coming winter. I think some of our listeners may have seen in the press as I have that some sources are predicting a snowier-than-usual winter in the New York area after last year, we had almost no snow.

Andrew Kruczkiewicz: Yes. I haven't looked into that. I think it's a good question. Now is the time of year to start thinking about that. I would advise the listeners to look at the National Weather Service Forecast for anything related to seasonal forecasts for snowfall. I think those are probably the best resources, and I could send them to you as well, Brian. There's a lot of information. There's a lot of different types of forecasts, different types of maps, on the National Weather Service website. Yes, their forecast quality is very good. There's a lot of testing and calibration that goes into it, and that's where I suggest going to look for that.

Brian Lehrer: Want to take us into some of that? I think we're science nerdy enough to handle a little bit because people may be thinking, "If it's hard enough to predict the weather hour by hour as you were describing before, how is it that we can predict it for a whole coming season?"

Andrew Kruczkiewicz: The rule for forecasts, the general rule is we're better at forecasting what's going to happen at a period of time closer in the future. In other words, if I look out the window, I can tell you what's very likely going to happen in the next few minutes, but yes, of course, every hour, a day, a week, it gets harder and harder. Now, we have different types of forecasts. Anything from let's say nowcasting, which is minutes into hours, into days, which is more traditional weather forecasting, we're using more deterministic forecasts. We can make statements such as, "On Thursday morning, we are likely to see a certain amount of rainfall."

However, as we go further out in time, we could talk about what a season may look like. We could make statements on what the, let's say October, November, December average rainfall would look like over that period of time. We're not going to make deterministic statements. We're not trying to say the exact amount of rainfall. Those forecasts are what we call probabilistic. We could talk about likelihood of above-normal rainfall over a season or the likelihood of below-normal rainfall for the season. That's how we get away with it actually. It's a different type of forecasts. Yes, that is an important part of understanding how these can be useful. What are the constraints and limitations of the forecast?

We also have a period called sub-seasonal, which is in between two weeks and two months. That is actually a very interesting gap in forecast skill. You very rarely see forecast for a month out or a month and a half out. It's usually from now out to two weeks, maybe 15 days, or you see these seasonal forecasts. There's a lot of active research at Columbia Climate School going on, on this sub-seasonal timescale to improve that period of time.

Brian Lehrer: Interesting. For listeners tuning in in the middle the news hook for this segment, a little bit tongue in cheek and a little bit serious, is that we seem to be in this weather pattern where we get drenched every Friday and Saturday. The rain seems to be on this seven-day cycle or I guess from Columbia thinks that that's not a real thing. It's a coincidence. Weather doesn't move in seven-day cycles, generally like the calendar does, but Michael in Manhattan is going to remember a winter a long time ago when that seemed to be happening with snow. Michael, you're on WNYC.

Michael: Hello, Brian. Yes. I was remembering right after I'd moved to New York, and I can't remember whether it was 1993 or 1994 that it snowed 13 out of 14 consecutive weekends. It would snow on Friday or Saturday, and it was a decent accumulation. There was snow on the ground for the entire winter.

Brian Lehrer: Is that a particular winter Andrew that stands out in meteorological history enough that you know it off the top of the head of your head from the caller's reference?

Andrew Kruczkiewicz: I have to check. What was the year again? Sorry, I missed it.

Brian Lehrer: '93, '94.

Andrew Kruczkiewicz: I'm not sure. I do know the--

Brian Lehrer: It was either the winter of '93/'94 or '94/'95, as he was saying.

Andrew Kruczkiewicz: Okay. I'm going to go check that. That was actually a period of time where I was getting into weather as a young meteorologist, I guess. I will go back and check that out. I think it's interesting that-- I always appreciate stories related to how people experience and remember meteorological events. Not only single events but also seasons. It is really a part of our experience. I think with climate change now, I'm hearing more and more stories like that. We're facing the reality of things changing, which also means we're trying to maybe somehow compare it to what used to be and try to figure out what does it mean to be in a changed climate.

Brian Lehrer: Well, to go back, not at all that far, back in 2021, after the flooding caused by Ida, you spoke on the station with WNYC's All Things Considered host Sean Carlson about why we weren't better prepared for that storm. Did you see progress and how we handled Ophelia last month?

Andrew Kruczkiewicz: There are many questions that I think we're asking now. Ida was one of the most disappointing experiences of my career. Just seeing what the forecast said and the warning and seeing the lack of interpretation and preparedness on various levels. One of the aspects of the recovery and rebuilding period that I think we need to evolve from is this idea of the reason why we saw the loss of life and the disruption of livelihood is that the forecasts weren't great and we need more forecasts. We need more data. I really don't think this is the case.

In many of the contexts where I work, there are too much data in too little time to really process them. What we really need are appropriate standard operating procedures driven by the community. What actions can the community take when certain thresholds are reached? It's much more on this translation of the forecast translation of risk, in order to promote and support the most underserved populations. That was one of the biggest issues for me.

Many of the communities that flooded this year are the same that flooded during Ida, and we were very close to seeing another catastrophic event. That's my suggestion. We need to do more at understanding flash floods specifically. I would like to see something of a task force specifically for flash floods. We must take this seriously. I'm not really sure what we're waiting for.

Brian Lehrer: Last question. As this weekend rain pattern seems to be predicted to continue at least for this weekend, is it going to rain for the marathon?

Andrew Kruczkiewicz: I was looking at the forecast just before the call, and there is a chance of rain. It looks like mostly on Friday afternoon, evening into Saturday. There's still some uncertainty in the forecast as always. We have a few days I would say. With each day closer to the marathon, the forecast quality increases. Right now the rainfall period looks like Thursday evening into Saturday. I would say check the National Weather Service. I think it's still the best source for weather forecasting in our region. Yes, that's my advice to keep an eye on.

Brian Lehrer: That's not till the first weekend in November. You have time to predict and so does the National Weather Service. Folks, you still have a little time to train. There we will leave it with Andrew Kruczkiewicz, research scientist at the International Research Institute for Climate and Society, part of Columbia University's Climate School. That's our climate story of the week. Andrew, thanks a lot.

Andrew Kruczkiewicz: Thank you, Brian.

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