Uncertainty Of Weather

Yesterday was forecast to be a very violent day in north Texas with regard to weather. The setup yesterday was the equivalent of a warehouse filled with gasoline, dynamite and aluminum powder. All the atmosphere needed was someone to drop a match and the whole works would have went up. The forecasts recognized this hazard and warned people accordingly. For a variety of reasons, the explosion never occurred and the majority of, but not all residents in north central Texas escaped with no damage. And I can accurately forecast today that there will be many who question the emphasis on danger yesterday, that the meteorologists hyped up the situation and that they don’t know how to predict weather.

All day the local stations had their meteorologists going over the situation and reminding people to be vigilant. Even the Storm Prediction Center opted to raise the alert level from enhanced to moderate, signifying that the conditions were right for explosive growth of violent storms. Needless to say, things became very tense as the day wore on. People began covering their cars with cardboard and mattresses, schools cancelled sports and some companies let people go home early. But as the first cumulonimbus towers started going up, the forecast changed. Instead of being ahead of the dryline, they went up behind it. This had a significant effect downrange on storm intensity.

In addition to that, the inversion cap was stronger than expected. This prevented the growth of storms to the extent that had been expected. In effect, much of the stored energy in the atmosphere was not available to be used to power the storms. There were a few discrete supercells that sprang up ahead of the front but not in the number or coverage that was expected. Some areas west and north of DFW did experience significant damage and a few storms became tornado warned but overall the widespread catastrophe never materialized.

Why are people upset?

To be honest, there are valid instances of media overhyping garden-variety snowstorms or treating a couple inches of rain over several days as a deluge. In my personal opinion, the overhyping of relatively benign types of weather is damaging to public confidence in forecasting and weather services in general. On the other hand, when there is a situation where violent thunderstorms are likely, there is a duty to remind people that failure to pay attention may cost them their lives.

Part of the confusion is that the severe forecasts had been in the news for about a week prior to the event. Forecasts that far out are based off of computer models of the atmosphere. The models take the current weather and interpolate possible scenarios for the future. As it gets closer to the actual forecast day, the models are refined with more up-to-date information, for instance did a upper level disturbance move the predicted 400 miles or did it actually move 450? Within 24 hours of an event, the importance of real-time atmospheric soundings and measurements for a given region becomes more important as meteorologists combine those readings with the models and their own knowledge to create a picture of what may happen.

Faced with this situation, forecasters have to make constant observations and continually update their prognosis. There are no models that can tell exactly where and when a storm is going to strike. It remains the province of humans both in weather centers and on the ground near the storms to make the final determinations. When the atmosphere is literally on the edge, it would be irresponsible to play down the significance. If even one person was killed by a falling tree or flying debris, every meteorologist would be skewered for not providing enough warning. The other extreme would be advising everyone to take shelter at the sight of a single cloud, resulting in public apathy and indifference.

The only solution is finding a balance between too little and too much information. People who grew up in Tornado Alley understand that for at least a couple months out of the year, the atmosphere conspires to ruin your life and treat it with the proper attention and respect. However, the recent influx of people from other states to the Dallas/Fort Worth area means that there are many people who do not understand that spring thunderstorms here are not like storms in any other part of the country. They are massive living things with nasty attitudes, both beautiful and sobering to see in person. A single storm can cover the better part of an entire county and tower twice the height of Mount Everest (for comparison, next time you ride an airliner, look out the window and imagine being twice as high). These storms do not take being ignored very well and lifetime residents understand this. It’s a situation where as cliché as it sounds, being safe is better than being sorry.

(My best friend who lives in New York got a rude introduction to Tornado Alley weather. When he arrived in Dallas for airline pilot training several years ago, he got to witness an EF-2 and car windows being shattered by golf-ball hail. It redefined his idea of a severe storm and made it impossible for him to watch Twister without laughing at the inaccuracies.)

Another aspect is misunderstanding the capabilities of weather prediction methods. We trust so much in technology that any uncertainty is met with fear and anger. “Why don’t you know if there’s going to be a tornado? Don’t you guys get paid enough? Why can’t you use your radars?” There is a limit to our abilities and short of meteorologists being pyschics, they cannot predict with street-by-street accuracy. There are quite literally millions of cubic miles of atmosphere that are in constant motion. Even a computer model that has 1 cubic mile resolution has a lot of uncertainty and needs to be qualified by other data that may or may not be available at a given time.

We also cannot discount the “pass-the-exam” attitude that has started to creep into society. Instead of understanding a concept, students will say to a teacher “Just tell us what’s going to be on the exam”, thus defeating the purpose of sitting in class and learning in the first place. With weather, many people don’t know or care about the lifted index, think that CAPE is something that a superhero wears and only want to know “Is it going to rain in my town?” A look at any meteorologist’s Facebook feed is evidence of this. Of the hundreds of questions being asked, a large portion of them are “Is it going to affect my town?” This behavior is understandable as people want to know if they should take action to protect themselves, but it also shows a lack of understanding of the massive scale on which weather systems operate (the same system that “didn’t happen” for north Texas spawned tornadoes in Oklahoma).

Finally, the emotional rollercoaster of imagining your home being destroyed, wondering how to protect your family and then being told “Nah, not today” can take its toll on anyone. The urge to lash out at the people responsible for your mental torture is understandable. However, there really is nobody to blame. The atmosphere is going to do what it’s going to do. All we can do as humans is pay attention and have a plan in case things get bad.

In conclusion, there are situations where media makes a big deal out of nothing. In fact with most severe storm situations, there literally is nothing until around 3pm. But there is a huge difference between naming a snowstorm that dumps a couple inches of powder versus telling people there’s a good chance that softball-sized blocks of ice are going to crash through your ceiling. There’s a difference between delayed school opening due to flurries versus finding a new school because the old one was shredded by a 200mph vortex. Alerts used properly are useful. Alerts that are used for anything other than blue skies has a detrimental effect on the public’s perception of weather forecasting and is something that must constantly be considered by producers of news programs.

Individuals must also take responsibility for their own knowledge about weather. Understand the difference between a watch and warning. Know basic cloud structures and what they mean about the atmosphere. Realize that a forecast can be absolutely accurate even if you personally experience the complete opposite. And most importantly remember that meteorologists are humans who are doing their best to decipher what the weather is going to do.

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