Forecast maps

Animation, Explanations, Archive

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Cloud Cover

Overcast

90% covered

80%covered

70% covered

60% covered

50% covered

40% covered

30% covered

20% covered

10% covered

Clear

The explanation of Cloud Cover Forecast is shown upon, according to the different sky color in different weather conditions, we use a 11-lever system for Cloud Cover Forecast. The Clear Sky Clock may put the high cloud too much. When the 7Timer! says it's "overcast", this overcast maybe very thin, thin enough to see the moon, planet or stars. It also could miss the smog near the ground. And it could not always give the exact time of the time those clouds/holes pass, and it may miss the thunderstorms in summer.

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Seeing

>5"

4"-5"

3"-4"

2.5"-3"

2"-2.5"

1.5"-2"

1.3"-1.5"

1.1"-1.3"

0.9"-1.1"

0.7"-0.9"

0.5"-0.7"

Observing planets, planetary nebulae or any celestial object with details at high power requires good seeing conditions. The seeing is the term used in astronomy to quantify the steadiness or the turbulence of the atmosphere. Seeing should not be confused with sky transparency, which is the terminology used to qualify the darkness of the sky. When we look at planets, we need high power to see all the fine details but most of the time we are limited by turbulence occurring in the telescope (local seeing) and/or in the atmosphere. 7Timer! Seeing forecast stacks turbulence of each layer from 850mb (about 1500m) to 100mb (about 20km), please note the actual seeing is slightly larger than the prediction.

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Transparency

Very Poor

Poor

Average

Good

Excellent

The explanation of Transparency Forecast is shown upon, we use a 5-lever system for Transparency Forecast. The Transparency discuss here includes atmosphere humidity and smog effect. The smog might have a bigger effect on transparency, e.g. in cities, the smog refract the lights and might makes the condition worse, than it in countryside. We'll discard the transparency output if the cloud cover is greater than 30%.

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Wind Speed

Calm

Light

Moderate

Strong

Storm

According to the Beaufort Wind Scale, we use a 5-lever system for Wind Speed Forecast, they are: Calm (<1.5m/s), Light (2-5m/s), Moderate (5-11m/s), Strong (11-17m/s), Storm (>17m/s).

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Humidity

<29%

30%-35 %

35%-40%

40%-45%

45%-50%

50%-55%

55%-60%

60%-65%

65%-70%

70%-75%

75%-80%

80%-85%

85%-90%

90%-95%

95%-99%

100%

The Relative Humidity can show the difference value between temperature and dew point. If the Relative Humidity is high, the dew will comes out much more easier. Though, the Humidity can change in a small region, e.g. in the mountains the Humidity may be higher than expect, so please notice this effect.

FAQ

Why appear "Entire grid undefined"?

Usually, on the early time (e.g. Release day - 03h/06h/09h), some parameter will say "entire grid undefined" because they require more data to calculate. To solve this problem, you can simply roll down your mouse and see later time.

Animation page doesn't work!

Because the size (20-50k) and the amount of the images, it's possible that when your connection is slow, the animation page does not taken effect. To solve this problem, you can click "skip forward" icon to load the image manually. I'm sorry about this problem, I'm still trying to develop a more "powerful" animation page.

If you feel there're some other elements need to be forecast, feel free to write me by the feedback form.