Tag: weather

Posted in Science & Nature

Hurricane

Posted on by Jinavie

We often hear on the news of cataclysmic storms with oddly common names such as Hurricane Sandy, Katrina and Harvey. It seems weird that we give such devastating forces of nature a basic name, let alone naming them human names at all.

A hurricane is the name given to tropical storms that occur in the Atlantic Ocean. For reference, a hurricane is essentially the same as a cyclone or typhoon. The history of naming hurricanes dates back over a hundred years, with residents of the Caribbean Islands naming hurricanes after the saint of the day from the Catholic calendar. Initially, American meteorologists named hurricanes by the geographic location that the storm originated in.

However, during World War II, military meteorologists in the Pacific started using women’s names for hurricanes. This made communication much easier as hurricanes could be identified by name and much easier to say. There are some apocryphal stories about the origin of women’s names for hurricanes, such as wishing that the hurricane will be calmer and of better temperament, or that they were named after the meteorologists’ wives and girlfriends. This practice soon spread to the rest of USA and became the default method of naming hurricanes. From 1979, it was decided that the gender of the names would be alternated.

In the present, there is a rolling six-year roster of 21 names each year in alphabetical order that is used to name hurricanes (see below for list). For example, the first hurricane of 2019 was called Andrea, the second Barry, the third Chantal and so on. In 2020, the first hurricane will be named Arthur, then Bertha, et cetera. The same names would be used in 2025 and 2026.

The one exception to this rule is that when a hurricane is particularly devastating and results in many deaths, the name is “retired” in honour of those who have lost their lives or livelihoods to the hurricane. For example, there will be no more hurricanes named Katrina or Harvey in the future.

Posted in Science & Nature

Discomfort Index

Posted on by Jinavie

Hot and humid weather is quite possibly the worst weather, as most people will feel sticky and uncomfortable, to the point that it will affect their mood and ability to think. This combination is so terrible that weather forecasts often mention a discomfort index (or temperature-humidity index) to highlight how hot and humid the day will be. Discomfort index is calculated as:

DI = 40.6 + 0.72 (dry-bulb temperature + wet-bulb temperature ).

Here, dry bulb temperature is the “ambient temperature” (not considering humidity), while wet bulb temperature accounts for humidity by looking at how low the temperature can get by evaporating water.

Evaporation absorbs heat but can only happen if the air is not saturated with humidity. Therefore, the more humid it is, the more “discomfort” we feel as we cannot sweat off the heat building up inside our bodies.

When the DI is at 70, about 10% of people experience discomfort. At 75, 50% feel discomfort and at 80, most people will feel extremely uncomfortable. A DI of above 85 is virtually intolerable and anything above this, serious conditions such as heat exhaustion and heat stroke can occur.

As our core body temperature rises and we cannot cool down by sweating, we experience thermal stress. Under thermal stress, our concentration and task performance begins to suffer – a phenomenon people will describe as their brain feeling as if it is melting. This is a well-established phenomenon that has significantly affected how architects design offices and homes to improve air flow and temperature control to create an environment with the least thermal stress possible – for both efficiency and comfort.

Posted in Simple Pleasures of Life

Simple Pleasures of Life #15

Posted on by Jinavie

Slipping into a warm, cozy bed while a thunderstorm rages outside.

Nothing soothes me and puts me in the right mood like a roaring thunderstorm and torrential rain~ When I’m warm and cozy inside and not drenched in rain that is. It just makes me feel so… safe and relaxed you know? Also, it’s perfect weather for napping, reading, gaming, snuggling, or whatever else 🙂

Posted in Simple Pleasures of Life

Simple Pleasures of Life #28

Posted on by Jinavie

Walking on sunshine.

So I mentioned before the awesomeness of staying indoors while it’s pouring outside, but the opposite is still awesome. Nothing lifts your spirits as much as a clear blue sky and beautiful sunshine, with a hint of a cool breeze~ Luckily spring is properly settling in in NZ, just in time for holidays next week!

Of course this being Auckland, the weather is as fickle as a teenage girl. That bitch will rain on you with no notice. Like, there’s no point looking at a forecast because it will most likely be wrong for at least half the day. But I digress.

Here’s a photo around the place I live, showing off awesome spring weather 🙂

Posted in Science & Nature

Thuder And Lightning

Posted on by Jinavie

The best or worst part (depending on your preference) about a dark and stormy night are the majestic flashes of lightning and booming thunder. Most people confuse the two terms, typically using “thunder” to describe both, but technically thunder is the sound produced by lightning, which is the flash of light. Lightning occurs when dense clouds become electrically charged due to the collision of water molecules. As charge builds up, the cloud becomes negatively charged. The negative charge becomes so intense that it begins to push electrons towards the surface of the Earth, creating a positive charge. Electricity always flows from a negative charge to a positive charge through a medium. The intensity of charges causes the air to become ionized (plasma), making it suddenly conductive and allowing the electricity to flow from the cloud to the ground. This is seen as a flash of intense light. As the electricity travels through this channel of air, it superheats the air and causes a massive expansion of air, much like an explosion. This creates an intense shockwave burst, producing a sound that we call thunder.

Lightning is a deadly force of nature. It clocks a peak voltage of somewhere between 30 million to billions of volts – far exceeding the electricity that can be generated by humans. When a lightning bolt strikes a human, it has a mortality rate of between 10~30%. The two effects of lightning on the human body is electrical shock and heat. As lightning flashes over the skin to reach the ground, it leaves a striking pattern known as Lichtenberg figures (see below), showing the path of the electrical breakdown. The intense electrical burst can cause loss of consciousness, arrhythmia or sudden cardiac arrest. The heat generated by the electricity can cause severe burns both externally and internally. It can literally fry internal organs causing permanent damage to the heart, lungs and brain. Neurological symptoms such as amnesia, confusion, sleep disturbance and chronic pain have also been reported. Strangely, there are also reported cases of lightning curing ailments such as blindness, deafness and baldness.

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Because lightning is light and thunder is sound, one can calculate how far away lightning struck using the time between the lightning flash and the sound of thunder. Sound travels at 340m/s, so by multiplying the number of seconds between the lightning and thunder by 340, you can deduce the distance in metres. For example, if you see a lightning strike and then hear thunder after 7 seconds, the lightning must have struck 340m x 7s = 2380m = 2.38km away.

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Posted in Science & Nature

Forecast

Posted on by Jinavie

When the weather forecast says today will be sunny, it always seems to rain (and vice versa). In fact, according to a US study, forecasts are sometimes less accurate than flipping a coin. If not even professionals can accurately predict the weather, can ordinary people like you and I do it?
The key to this is observation. By carefully studying your surroundings, you can look in to the future.

There are many signs before rain comes. For example, if the sunset is unusually clear or if a mountain far away looks smaller or hazy then it is very likely that it will rain the next day. If you see a rainbow in the morning it suggests rain is coming from the west. On hot days without any wind, it is likely there will be a heavy shower.
Animals are also adept at telling the weather. Frogs crying, worms coming out and swallows flying low are all signs that the air is humid and rain is coming. Swallows are especially accurate, as they fly low to catch insects that cannot fly high due to the humidity weighing them down.
If you are at the beach and there is a swarm of jellyfish, avoid going out to sea. Jellyfish near the coastline is a premonition for a storm. 

If a more accurate weather prediction is required, the most precise method is cloud observation. If you study them carefully they comprise three tiers, with some clouds rising vertically.

Clouds in the highest level

  • Cirrus: Very fine, white feathery clouds that almost look combed over. If these clouds are curvy and organised the weather will be fine, but if they appear banded or spread chaotically they can gather and form rainclouds and start a shower.
  • Cirrostratus: Looks like a veil of cotton curtaining the sky. They cause halos around the sun and moon, which is a sign of imminent rain.
  • Cirrocumulus: Looks like a spread of seashells on a beach. If you find these clouds over a beach in winter, it will rain soon.

Clouds in the middle level

  • Altocumulus: Either appears as an ordered stream of rounded clouds, or looks like a herd of sheep. If these clouds shrink in size, the weather gets better (and vice versa).
  • Altostratus: Shaped like streaks of veil across the sky. They are often light grey or very dark. If they become thicker or sink to a lower level, it is a sign that the weather will be cloudy with a chance of rain.
  • Nimbostratus: The common “raincloud”, bringing rain and snow.

Clouds in the lowest level

  • Stratocumulus: Clumps of clouds that appear in layers without clear boundaries. You can see clear sky through gaps between them. If you can see clouds that were cumulus in the afternoon changing to stratocumulus by sunset, the weather will be great the next day.
  • Stratus: Looks like fog covering a low sky. If they come in the morning and disappear by night, that day will be clear. However, if they lie between altostratus and a canyon, it will rain.

Clouds that rise vertically

  • Cumulus: Fluffy clouds that you can see on a clear sky. If they disappear by evening the next day is clear, but if they can be seen late at night or float north-westerly, it is a sign that it will rain.
  • Cumulonimbus: Massive cloud pillars that rise to the level of cirrus. It always brings heavy rain and sometimes a thunderstorm.

If you know how to observe and analyse cloud patterns, you can predict the weather even when stranded on a desert island.