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Meteorology of storms tests – an example

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The meteorology of storms tests is an important field of meteorology.

Why? Because the the storms command our attention.

They are one of the more energetic expressions of weather. They harness the great power of the so-called Convectively Available Potential Energy, CAPE, and can suddenly change the fates of people, buildings and nature when this is unleashed.

We desire the help of storm modification techniques, which respond to our tests and any strong likelihood of severe storm development the tests may indicate.

Professionals practicing meteorology of storms tests investigate

• hurricane storms, (see nhc.noaa.gov for more)
• tornados,
• thunderstorm clouds and
• other meteorological disturbances such as…
• thunder and lightning,
• damaging winds,
• blizzards,
• hail and
• flooding

…in order to provide realistic forecasts. The scientists verify the data by comparing with radar, satellite, modeling applications and software output.

Canadian meteorologists use unique tools to predict disturbing weather and make more timely warnings. They check Doppler radar for weather data and then bring other forecast and assessment resources on board.

We want more accurate severe weather forecasting. That means no missed events in the forecast and no false positives.

That's a pretty tall order and nobody can achieve it quite yet, but we're working on it. And the Marion Bridge Weather Radar and others like it have been the pride of Environment Canada. They enable internal analysis of a storm cell never before achieved.

The public gets urgent info via Special Weather Statements and Severe Weather Warnings.

An Analytical Technique for meteorology of storms tests

One of the tests we use to evaluate convective storms is called the Miller Technique. It looks at pressure trends, isobars, at various levels of the atmosphere.

Here we identify high level jet streams at above 30,000 feet (250 millibars of pressure), to identify a jet core. Then try to find vertical motion and wind shear at around 20,000 feet (500 mb), as well as any trough axis at this level.

A

trough axis is an imaginary line along which every lateral direction you go gets you into warmer air. It helps you find instability.

A ridge is just the opposite where nearly all directions have colder air. Forecasters also look for areas where vertical motion is about to increase – likely due to vorticity advection.

The next level is approximately 10,000 feet or 700 mb. Again we look for signs of wind shear, changes in speed or direction over a short distance.

We try to find any ridges or troughs like those described above. And moisture. This level is notorious for containing and transporting great amounts of water vapour. We can also look for telltale signs such as dry intrusions and vertical motion. 5,000 feet (850 mb) gives us more meteorology of storms tests and criteria.

Now look for a low level jet, a river of wind above the ground, or low level convergence, air rushing into one spot. Also see if you can find streams of high humidity and temperature.

Finally, locate this same list of features at ground level, sudden pressure changes and sharp changes to dry air. This is already a long list of ingredients. We try to find as many of them above one location as we can, to provide good evidence of a pending storm.

Add to that a number of parameters for calculating stability and potential energy and this sophisticated Miller Composite becomes a very useful, if cumbersome, tool for the severe weather meteorologist.

Why bother?

Severe storm weather forecasts come from the intense work of experienced meteorologists. They try to assure that all the weather causing disasters are minimized by providing good information with enough lead time to be useful. We want people to be more conscious about their safety and take necessary precautions, acting responsible for their own selves and the well being of their environment.

To be as sure as possible, meteorologists use optimized data and equipment like the radars described above before presenting shocking forecasts.

Vigilant weather observations help forecasters keep track of weather events and phenomena. And meteorologists who work in research laboratories investigate internal mechanisms for severe weather development.

At the same time the meteorology of storms tests attempts to improve severe weather warnings in order to be able to control public vulnerability. That's kinda the point.

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