How to read Meteogram
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@yves70 said in How to read Meteogram:
@hgk209
First of all, we should get the confirmation about the exact meaning of the shades of grey. Is it humidity level or cloud cover ? High level of humidity doesn’t necessary mean clouds -
@cougar83
Grey shades in the meteogram are linked to relative humidity, not cloud cover -
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That's great. What if I want to plan sailing from the Chesapeake to the Grenadines, a few months in advance. Is there historical data?
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@fhamilton36
No Windy does not provide historical data.
Better to use the Pilot Charts than verifying days after days what was the weather during the last 10 or 20 years:
https://community.windy.com/topic/9788/historical-wind-data?_=1619461576536 -
Hello!
If there is rain in the Meteogram at 4AM, does it mean it will rain from 1AM to 4AM, from 2:30AM to 5:30AM or from 4AM to 7AM? Thank You! -
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@vsinceac Thank You!
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Hi, I've just found that the values of the 'last 3 hours' precipitation are different in the Meteogram and the layer data. For example, in this picture (https://imgur.com/k0uKcEq), the value derived from the weather picker is 71mm, but the value from the basic Meteogram on the same point is 92mm, which one is correct? Is it resulted from the different definition of the two rainfall value?
Another question is, the value of 'Rain' in Meteogram is 78mm, and the convective rainfall is 14mm. And the sum of them is equal to the value in the basic meteogram, 92mm. So the 'blue Rain' term is actually the 'large-scaled precipitation?' and the value 92mm is the total precipitation, the sum of large-scaled and convective precipitation, right?
Thank you!
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@greatkingnan Hello, the values are different since they are calculated differently. The Rain, Thunder layer shows accumulation in the last 3 hour.
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@korina Thanks! So the value in Meteogram is the precipitation accumulated over a quite different time period compared to the Rain & Thunder layer? What's the time period you'd applied to do the calculation?
And I'd like to know whether the value of 'rain' in Meteogram & Airgram represents the large-scale precipitation or not? According to the description of parameter on ECMWF's website, total precipitation is the sum of large-scale & convective precipitation. It seems that the total amount of precipitation has been split into two parts in the bar graph in Meteogram: the large-scale term and convective term. Furthermore, the sum of 'Rain' and 'Covective' is exact the value in basic list, which might indicates the total precipitation. As a result, the term 'Rain' might be interpreted as the large-scale precipitation part in Meteogram.
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@greatkingnan Hello, the Rain, Thunder layers shows data for last 3 hours. The detailed forecast shows data calculated for 3hr or 1hr depending if you are Premium user or not. Therefore those values cannot be the same.
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@korina Thanks for your help! Yes, I know exactly the data in Premium version and free version are different. But...Actually, I'm trying to figure out the differences between the rainfall values shown on the 'Rain & Thunder' layers and basic weather forecast on the same place. I just found they aren't exact the same value, especially for heavier rainfall cases, so I have no idea which one is correct. I guess it might be caused by the different definition of accumulated time period or the interpolation between each grid point.
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@greatkingnan Hello, detailed forecast or Rain, Thunder layer shows different data based on different calculations. Detailed forecast is more precise if you want to check the predicted amount of precipitation.
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Thanks, Korena for your very easy to understand description♪
Meteogram on Windy.com is my favourite weather forecast❤ -
What is the arrow on my location pointing towards? As I turn to face a different direction, the arrow swings to point toward something else. It's not making any sense to me; what is its purpose?
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This arrow appears at your GPS position on the Radar layer and shows a fixed or inconsistent direction. It has no use.
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Hi,
I wanted to know what criteria you use for the elaboration of the meteograms. this is the one from the ECMWF.https://confluence.ecmwf.int/display/FUG/Selection+of+grid+points+for+Meteograms
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@fran_j Please have a look at https://community.windy.com/topic/10309/cloudbase-meteograms?_=1630065415375
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Very good summary, very helpful to the net friend ~
