computer science

SIGWX

SIGWX is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand SIGWX rather than just read about it. In short: SIGWX is a Significant Weather Chart defined by ICAO. Weather charts being issued by World Area Forecast Centres (from meteorological offices in London and Washington), presenting the most important meteorological phenomena relevant especially for air traffic transport.

Key takeaways

SIGWX belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect SIGWX to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of SIGWX from memory before moving on to harder problems.

Reference excerpt

SIGWX is a Significant Weather Chart defined by ICAO. Weather charts being issued by World Area Forecast Centres (from meteorological offices in London and Washington), presenting the most important meteorological phenomena relevant especially for air traffic transport. WAFC publishes them in two formats

BUFR code PNG images Charts are typically being issued every six hours (0, 6, 12, 18 UTC). The SIGWX charts only show the forecast for the specific hour, however it is common place for parameters such as the JetStream, CAT & CB to be interpreted +/- 3 hours of the chart validity time. Prognoses are typically prepared for two ranges of heights:

SWH - High Level SIGWX (Flight level 250-630) SWM - Medium Level SIGWX (Flight level 100-450) Weather phenomena:

Cloud - including information about cloud type, height of base and top, turbulence and icing risk Clear Air Turbulence - including base and top height, strength of turbulence Jet Stream - including base and top height, wind speed Tropopause Height Tropical Cyclone, Sandstorm Volcanoes Frontal system IMPORTANT NOTE: Amendment 74 to ICAO Annex 3 (effective 7 November 2007) eliminated the requirement for depiction of surface fronts and well-defined convergence zones (e.g. ITCZ) on WAFS SIGWX forecasts (in BUFR-code and PNG chart form). WAFC still publishes frontal bulletins, but they contain no data.

References

Worked examples

Example 1 — a first encounter with SIGWX

Start with the simplest possible case. Write down what SIGWX claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to SIGWX before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about SIGWX ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of SIGWX

In research: SIGWX appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses SIGWX in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: SIGWX is common in secondary-school and first-year university syllabi. It links to neighbouring topics Earth sciences data formats, Meteorological data and networks, so understanding it makes those chapters shorter.
In everyday life: Look for SIGWX outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study SIGWX in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what SIGWX means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain SIGWX out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is SIGWX in simple terms?

Why does SIGWX matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study SIGWX?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on SIGWX.