The Philippine Onion

Lies and half-truths shall set you free

The art and science of weather forecasting and why we can’t predict Mina

Posted by commiedyan on November 26, 2007

Our weather forecasters have drawn a lot of undeserved flak for the way Mina has skirted the areas she was supposed to damage. We must be so cynical we can’t even recognize good news.

From the Philippine Daily Inquirer is this report: Mina’s veering off sparks text jokes in Albay. We hope you don’t mind if we’re occasionally serious.

But first a joke from Onionista. Typhoon Mina changed course, from B.S. Meteorology to A.B. Political Science and she’s now in Malacañang meeting with Gloria, Cerge Remonde,Ronnie Puno, and Ignacio Bunye, trying to spin the whirlwind and grab credit for the minimal destruction thus far.

Now for the serious weather jokes:

  1. “I am not sure how clouds get formed. But the clouds know how to do it, and that is the important thing.”
  2. “In making rain water, it takes everything from H to O.”
  3. Water vapour gets together in a cloud. When it is big enough to be called a drop, it does.

Here’s the source of these corny jokes,

Now this is the source of the serious stuff. There are two mainstream methods in weather forecasting.

  1. The persistence method:This is the simplest way of producing a forecast. The persistence method assumes that the conditions at the time of the forecast will not change. For example, if it is sunny and 87 degrees today, the persistence method predicts that it will be sunny and 87 degrees tomorrow. If two inches of rain fell today, the persistence method would predict two inches of rain for tomorrow.
  2. Numerical Weather Prediction: Numerical Weather Prediction (NWP) uses the power of computers to make a forecast. Complex computer programs, also known as forecast models, run on supercomputers and provide predictions on many atmospheric variables such as temperature, pressure, wind, and rainfall. A forecaster examines how the features predicted by the computer will interact to produce the day’s weather. The NWP method is flawed in that the equations used by the models to simulate the atmosphere are not precise. This leads to some error in the predictions. In addition, the are many gaps in the initial data since we do not receive many weather observations from areas in the mountains or over the ocean. If the initial state is not completely known, the computer’s prediction of how that initial state will evolve will not be entirely accurate. Despite these flaws, the NWP method is probably the best of the five discussed here at forecasting the day-to-day weather changes. Very few people, however, have access to the computer data. In addition, the beginning forecaster does not have the knowledge to interpret the computer forecast, so the simpler forecasting methods, such as the trends or analogue method, are recommended for the beginner.

Weather forecasting shares some characteristics with economic and political forecasting. The forecasters never get sued.

You might be wondering why we’re in a good mood. We just got over a persistent tropical depression. Smile naman.

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2 Responses to “The art and science of weather forecasting and why we can’t predict Mina”

  1. WillyJ said

    As this is written, tropical Storm Lando turned around and headed back
    toward the Philippines, aiming for the Southern Tagalog region.
    “With Lando’s bizarre return, thousands of evacuees who had gone back home in the Bicol Region after Mina passed, headed back for evacuation centers to avoid Lando’s renewed onslaught, relief officials said.”
    This simply illustrates the butterfly effect in weather forecasting, which states that a “butterfly flapping its wings in Brazil could set off a tornado in Texas.” This further points us to a known corollary of Murphy’s law, that “Nature always sides with the hidden flaw.”

    Whatever, less damage, so yes we’re smiling. But I pity the poor weather forecasters, probably the most ridiculed people next to politicians. They better switch jobs to political forecasting instead. At least when a political forecast turns out wrong, they can always blame the weather.

  2. commiedyan said

    Aray!! Mina.

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