Interpreting a 50% chance of rain

We have had multiple days recently where there is a threat of rain all day. The hourly forecast from yesterday was not unusual:

One of my first thoughts in seeing such a forecast is to say that there is a 50/50 chance of rain. Flip a coin. With this in mind, I would not necessarily stay inside but I would be prepared when going outside.

The idea of a meteorologist flipping a coin when predicting rain is tempting. This could lead to thinking that the meteorologists do not really know so they are just guessing.

However, this is not exactly how this information works. If I look at the hourly forecast and see 0% chance of rain or even anything under 20-30%, I am not going to worry about rain. The probability is low. In contrast, if I see 70% and above I might alter my behavior as the probability is high.

The 50/50 information is still very useful even if it leaves a reader unsure if there will be rain or not. It is not conclusive information but it is not no information or just a guess. With rain at 50%, bring an umbrella, have a coat, or do not stay too far away from shelter but do not just stay inside.

Searching for well-presented weather forecasts; example of Weather Underground

Finding good and well-presented weather forecasts can be difficult. What provider supplies accurate information? Use a widget, app, or website? And who puts it together best on the screen? I have settled on Weather Underground because they present data in this format when you look at the ten day forecast:

This is a lot of information in one graphic. Here is what I think it does well:

  1. The top still provides the basic information many people might seek: conditions and high and low temperatures. A quick scan of the top quickly reveals all of this information.
  2. The amount of information available each day is helpfully shown in four sets of graphs below the header information. I do not just get a high and low temperature; I can see this over an hourly chart (no need to click on hourly information). I do not just get a notice about precipitation; I can see when rain or snow will fall. I do not just get a summary of wind speed; I can see if that wind speed is consistent, when it is rising or falling, and the direction.
  3. Connected to #2, it is easy to see patterns across days. Will that rain continue into the next day? Is the temperature spike or drop going to last? The longitudinal predictions are easy to see and I can see more details than just the summary info at the top.
  4. Also connected to #2, I can see how these four different paths of data line up with each other at the same days and times.

In sum, I think Weather Underground does a great job of showing a lot of information in an easy-to-decipher format. This may be too much information for many people, especially if you want quick information for now or the next few hours. But, if you want to think about the next few days and upcoming patterns, this one graphic offers a lot.

One way or another, suburban sidewalks will be cleared of snow

Because of different regulations and community guidelines, sidewalks in the suburbs could be cleared quickly of snow – or not. Of course, they all will be clear eventually as the weather warms up.

The continued onslaught of heavy, back-straining snow was hard enough to tackle. When a deep freeze solidified it, many people surrendered their shovels in defeat.

The result left sidewalks covered with snowdrifts in neighborhoods and along busy streets. Some pedestrians could be seen walking on busy roads rather than wading through sidewalk snow, a risky strategy at best…

Across the suburbs, “there’s no uniform code” for sidewalk snow removal, Czerwinski explained. “Some communities have an ordinance, which sets in place whose responsibility it is, and it’s usually the property owner, and it’s a requirement. Other municipalities only encourage residents to shovel snow. Some municipalities say nothing.

“It’s not the norm in the metro region, but some cities such as Highland Park do plow sidewalks, taking a tiered approach. The city plows 32 miles of sidewalks near schools, Metra stations, public buildings and shopping districts — no matter how much snow falls, according to Highland Park’s website.

Given the unique snowfall in the last month or so in the Chicago area, there were several keys to keeping sidewalks and driveways clear:

-Keep up with the various snowfalls. If you let multiple snows happen or do not clear the snow completely each time, it piles up, melts in layers and then freezes, and takes longer to clear.

-Use a shovel with a steel edge. This helps scrape the surface clear rather than just gliding over the top.

-Snowblowers cut down on the physical effort needed but they do not always get to the bottom of the snow. They instead can leave an inch or two at the bottom that becomes tramped down and stays on the surface longer.

More broadly, I wonder if the sociologists who study collective efficacy would see snow removal as a reliable marker. Do people go out of their way to help each other? Is the block or community more important than just clearing individual driveways and sidewalks? The Chicago system of “dibs” where people physically mark off their cleared parking spaces for their own use is interesting to consider in this light. But, so might be the suburbanites who leave their own property immaculate but nearby paths are not cleared. In this case, does the snow clearing become more of a status symbol like a dandelion-free lawn or yard free of leaves rather than an interest in public welfare?

(With all the snow that fell and is now melting, it is also time to consider drainage issues present in many suburban areas. Where can all the water go?)

Learning to drive in the snow requires practice and caution

With cold and snow in much of the United States, a car dependent society runs into more difficulties driving. What it does it take to learn how to drive in the snow? Practice and caution. Let me explain.

As a newer driver, I had opportunities to gain valuable practice in driving in snow and bad conditions. I remember one time driving home from work on a school night at about 8 PM after several hours of snowfall. The road was completely covered but the path of the road was discernible amid trees and other markers. Hardly anyone else was out. I made it home by driving slowly.

Around the same time and working at the same place, I found myself leaving for work at 6:30 AM one winter morning. I did not give the car much time to heat up so when I pulled out of our subdivision on to the main road, the rising sun hit my not-clear windshield and made it impossible to see out the front. I stopped, rolled down my window, and slowly drove forward a short distance until I could pull over, let the car warm up, and have a completely clear windshield.

These were potentially risky situations. They were also learning experiences. Pair these experiences – and numerous others – with a few clear rules for driving in snow and icy conditions. First, do not follow anyone closely. Give yourself more space between vehicles. Second, brake slowly in case you start slipping. This means you need to start slowing down earlier. Third, adjust your speed for conditions. Watch how other vehicles are doing and how clear the roadway is.

Wintry conditions are not always possible to handle but are often manageable with practice and caution. These guidelines are less helpful if drivers have fewer opportunities to drive in such conditions. And even following these guidelines is no guarantee; a driver cannot control the actions of other drivers and surprises can arise (such as unseen ice). Even as we ask new drivers to practice certain maneuvers and skills, perhaps we should add snow and ice experience to that mix. Or, maybe it should be a bonus certification required for some parts of the country and recommended elsewhere.

When infrastructure does not work as expected, Texas grid edition

The bitter cold in Texas has created problems for the grid. I found a 2011 article helpful in understanding a bit more about how power works in Texas:

Photo by Mikhail Nilov on Pexels.com

The separation of the Texas grid from the rest of the country has its origins in the evolution of electric utilities early last century. In the decades after Thomas Edison turned on the country’s first power plant in Manhattan in 1882, small generating plants sprouted across Texas, bringing electric light to cities. Later, particularly during the first world war, utilities began to link themselves together. These ties, and the accompanying transmission network, grew further during the second world war, when several Texas utilities joined together to form the Texas Interconnected System, which allowed them to link to the big dams along Texas rivers and also send extra electricity to support the ramped-up factories aiding the war effort.

The Texas Interconnected System — which for a long time was actually operated by two discrete entities, one for northern Texas and one for southern Texas — had another priority: staying out of the reach of federal regulators. In 1935, President Franklin D. Roosevelt signed the Federal Power Act, which charged the Federal Power Commission with overseeing interstate electricity sales. By not crossing state lines, Texas utilities avoided being subjected to federal rules. “Freedom from federal regulation was a cherished goal — more so because Texas had no regulation until the 1970s,” writes Richard D. Cudahy in a 1995 article, “The Second Battle of the Alamo: The Midnight Connection.” (Self-reliance was also made easier in Texas, especially in the early days, because the state has substantial coal, natural gas and oil resources of its own to fuel power plants.)

ERCOT was formed in 1970, in the wake of a major blackout in the Northeast in November 1965, and it was tasked with managing grid reliability in accordance with national standards. The agency assumed additional responsibilities following electric deregulation in Texas a decade ago. The ERCOT grid remains beyond the jurisdiction of the Federal Energy Regulatory Commission, which succeeded the Federal Power Commission and regulates interstate electric transmission.

Historically, the Texas grid’s independence has been violated a few times. Once was during World War II, when special provisions were made to link Texas to other grids, according to Cudahy. Another episode occurred in 1976 after a Texas utility, for reasons relating to its own regulatory needs, deliberately flipped a switch and sent power to Oklahoma for a few hours. This event, known as the “Midnight Connection,” set off a major legal battle that could have brought Texas under the jurisdiction of federal regulators, but it was ultimately resolved in favor of continued Texan independence.

I have contended before that few people pay much attention to infrastructure until something goes wrong. When electricity, natural gas, water, roads, mass transit, and more operate normally, we do not think about them much. They just work. Until they don’t.

A short event last summer reminded me of this. Our family was about to leave our house for a trip and right as we were closing everything up, the power went out. In such a situation, what do you do? Stay and make sure all essential systems are back on – refrigerator, sump pump, air conditioning – before leaving? Just go and hope for the best? We stuck around for a little bit, power was restored, and we were on our way. And this happened in a location where we rarely lose electricity and most of the power lines are underground.

Our situation was a drop in the bucket compared to a severe storm or change in weather like Texas is experiencing. It all works until it is knocked out and millions of people are affected. Then, everyone wants to know what is going wrong. What is taking so long? Is there a way to quickly reestablish service or are people at the mercy of the cold? Certainly, the return of power and services will be accompanied by serious conversations about what to do to ensure something similar does not happen again.

And then there are the peculiarities of local infrastructure. How was it built? How is it managed? Who makes the decisions and what are the priorities for the systems? Is it prepared for a crisis? Some places take great pride in the infrastructure. As an example, the Chicago story of reversing the Chicago River to help improve public health is told over and over as a notable achievement. The construction of Deep Tunnel is a sizable project.

But, these are the big projects. Power, gas, and water are just supposed to be there. While some property owners, often in more rural areas, might have to deal with this more on their own (wells, propane tanks, septic fields, etc.), this is part of the urban and suburban bargain: you live there and the services work (and might even be relatively cheap – see the example of water).

Perhaps this will lead to more consideration of infrastructure. Build a strong infrastructure and it will help keep different and important parts of society running. When it fails, everyone struggles.

Fewer plane flights, worse weather forecasts, collecting data

The consequences of COVID-19 continue: with fewer commercial airline flights, weather models have less data.

white clouds and blue sky

Photo by Ithalu Dominguez on Pexels.com

During their time in the skies, commercial airplanes regularly log a variety of meteorological data, including air temperature, relative humidity, air pressure and wind direction — data that is used to populate weather prediction models…

With less spring meteorological data to work with, forecasting models have produced less accurate predictions, researchers said. Long-term term forecasts suffered the most from a lack of meteorological data, according to the latest analysis…

Forecast accuracy suffered the most across the United States, southeast China and Australia, as well as more remote regions like the Sahara Desert, Greenland and Antarctica.

Though Western Europe experienced an 80 to 90 percent drop in flight traffic during the height of the pandemic, weather forecasts in the region remained relatively accurate. Chen suspects the region’s densely-packed network of ground-based weather stations helped forecasters continue to populate models with sufficient amounts of meteorological data.

Models, whether for pandemics or weather, need good input. Better data up front helps researchers adjust models to fit past patterns and predict future outcomes. Absent of data, it can be hard to fit models, especially in complex systems like weather.

As noted above, there are other ways to obtain weather data. Airplanes offered a convenient way to collect data: thousands of regular flights could lead to a lot of data. In contrast, constructing ground stations would require more resources in the short-term.

Yet, any data collector needs to remain flexible. One source of data can disappear, leading to a new approach. Or, a new opportunity might arise and switching methods makes sense. Or, those studying and predicting weather could develop multiple good sources of data that could options or redundancy amid black swan events.

Few may recognize all of this is happening. Weather forecasts will continue. Behind the scenes, we might even get better weather models in the long run as researchers and meteorologists adjust.

Will there be more lawn mowing or less lawn mowing with climate change?

If the climate is changing with some places predicted to receive more rain and some to receive less rain, how will this affect lawn mowing in the United States? A few quick thoughts:

1. If droughts (such as a few years back in California) and high temperatures are more common in certain places, more people could seek alternatives to lawns (looking for less water use or greywater use plus painting lawns or replacing them). Less lawn mowing!

2. If rain is more common elsewhere, this could lead to lusher lawns, the dream of many suburban property owners. More lawn mowing!

3. Producers of grass seed, lawn mowers, and others would have to adjust. This is a sizable industry that could pursue a variety of paths. Still sell the perfect lawn concept in wetter parts of the country while also selling lawn alternatives in drier regions? Selling hardier and less water dependent seeds in drier areas? I assume they already have plans. Perhaps more lawn mowing if people still want lawns and the right products are available?

4. This could affect how Americans regard the lawn. While the nicely kept green grass lawn seems fairly widespread, perhaps it will be a strong norm in some regions with significant variation elsewhere. How much this could affect other areas of homeownership and suburban life is hard to foresee. A wash for overall lawn mowing?

5. The doomsday scenario: perhaps other problems become so pressing that few care about lawn mowing. For example, why mow the lawn when food supplies are limited?

This question came to me after several stretches this year where rain and humidity constant for a few weeks. This required more mowing then and we have not experienced the typical July/August browning of the lawn because of the rainy spells.

Extreme cold leaves parting gift: potholes

The cold in the Chicago area and Midwest may have receded but the potholes have just begun:

Streets already showing signs of deterioration are vulnerable to potholes, said Adam Boeche, Mundelein’s director of public works and engineering.

“Once the snow and ice melt, the water begins to infiltrate into the base of the pavement. Then it freezes again, causing the base to heave and expand the roadway surface,” Boeche explained. “If there are already cracks in the surface, they begin to separate more, thereby losing the integrity of the pavement and forming potholes.”

Drivers and residents are encouraged to report potholes to local public works departments. People should drive slowly and cautiously when navigating streets with potholes, said Lincolnshire Public Works Director Bradford H. Woodbury…

Cepeda’s advice on avoiding potholes is simple: Keep your eyes on the road.

So if the driver in front of you is swerving, it may be because they are distracted by their cell phone and it may be because they are trying to avoid a pothole.

More broadly, I’m a little surprised that I have not heard more over the years about construction techniques or research into avoiding potholes in roadways. If we can make permeable roads and roads that can absorb pollution, why not one that is more resistant to potholes or even roads that could be self-healing? The short answer likely is that asphalt roads are relatively cheap to build and repair. At the same time, potholes can be costly and take a toll on many vehicles.

Chicago’s clout extends to receiving more news coverage of cold even as Minneapolis was colder

Despite concerns at times, Chicago is indeed a leading global city. This week suggests another way this might play out: the cold temperatures and wind chill in Chicago received a lot of media attention while the colder temperatures in Minnesota and north of Chicago received less.

 

There are several ways to think about this:

  1. People expect Minnesota and places north of Chicago to be colder so when they are extremely cold, this is less noteworthy.
  2. Fewer people live in the cities north of Chicago so the cold affects fewer people.
  3. Chicago is a much higher-status city and any news in Chicago is going to outweigh news in Minneapolis.

Perhaps all of these factors may be at play and interrelated. Reasons #2 and #3 are connected: Chicago has a higher status in part because of its larger population. Similarly, leading global cities tend not to be located too far north or south (connecting reasons #1 and #3).

This may help Chicagoland residents feel better about the severe cold: people throughout the United States and even the world note the cold you are experiencing because of your city’s status.

Significant vs. substantive differences, urban vs. suburban snow totals edition

Meteorologist Tom Skilling discusses the difference in snowfall between urban and suburban parts of the Chicago region. In doing so, he illustrates the differences between significant and substantive significance:

Dear Tom,
Why do Chicago’s suburbs get more snow in the winter than Chicago itself?
— Matt, Palatine

Dear Matt,
I do not believe that to be the case. For example, the annual snowfall at Midway Airport is 39.3 inches (Midway being closer to the lake than O’Hare); at O’Hare International Airport, it’s 37.6 inches; at Rockford, 38.3 inches. The differences aren’t large, but they are significant nonetheless. Lake Michigan enhancement of snowfall totals and the occurrence of lake-effect snows in locations closer to the lake all argue that more snow will fall with some regularity at lakeside locations.
Please note that these are generalized statements. Individual snow events will not necessarily conform to the “more snow near the lake” phenomenon. However, averaged over a period of many years, lakeside locations receive more snow than inland locations.

Because the weather data is based on decades of data, we can be fairly confident that there is a difference in snowfall between the three locations mentioned. The location nearest the lake, Midway, receives more snow, Rockford, furthest from the lake, receives a little less snow, and O’Hare, in between though much closer to the lake than Rockford, is in the middle.

On the other hand, there is very little substantive difference between these totals. Over the course of an entire year, the spread between the averages of the three locations is only 1.7 inches total. That is not much. It is likely not noticeable to the average resident. Similarly, I can’t imagine municipalities act much differently because of less than two inches of snow spread out over a year.

This illustrates an issue that often arises in doing statistical analysis: a statistical test may show a significant difference or relationship in the population but the actual difference or relationship is hard to notice or not worth acting on. Here, the data shows real differences in snowfall across locations but the real-world effect is limited.