Best posts made by TZ
Why is Wind speed in hurricanes so wrong?
Question: Why reported wind speed of hurricane is much higher than value forecasted by Windy?
Answer: Windy displays ECMWF or GFS global forecast model. Neither of them is capable to predict exact peak values.
- Modeling: Numerical model computes grid that has finite resolution in both space and time (~10km in space horizontally, ~100-1000m vertically, ~1-6h in time). Peak values are smoothed, because of coarse grid resolution.
- Analysis of input data: Calculations are based on measurements. They come from stations, radars, satellites and other sensors. These sensors are not always reliable, so extremal measurements can be considered as errors during data assimilation and thrown away to avoid damaging the computation.
- Numerical models are not good at prediction of local extreme values and phenomena. Examples: tornadoes, convective storms, hails, single convective clouds, single orographic clouds, extreme wind speed in storms or hurricanes.
- Numerical models are good at prediction of averege and "smooth" values. Examples: average wind in last 3 hours, temperature, humidity, pressure field.
RE: Propose a NEW LAYER / FEATURE You'd like on Windy
Altitude and coverage of convective clouds (cumuli) ...I will implement it one day :-) but if there are more people wanting this, please upvote!
RE: Cloudbase & Meteograms
@Edgington Hi, this is probably because of different calculation of both values.
Cloud base is directly taken from ECMWF parameter called "ceiling". It is height (above model orography i.e. AGL) of cloud layer covering more than 50% of the sky. It estimates height where you can expect "significant clouds". Detailed description is here: https://confluence.ecmwf.int/display/FCST/43r1+new+parameters%3A+Ceiling
On the other side the grey meteogram is calculated from relative humidity. It can be explained as a distribution of water in the atmosphere. The height in the meteogram is in pressure levels. km/ft values are only rough estimation and they are AMSL. I admit that this can be confusing.
Possible explanation of the difference: There could be signigicant humidity (almost 100%), so there are drawn clouds in meteogram, but the cloud coverage according to ECMWF is less than 50%, so the ceiling is considered to be higher.
In such strange case it is better to look also in cloud maps, which can give you better overview. However, if the location is in the mountains then the values can be misleading, because model orography is very rough.
RE: Premium subscribers will get premium support
@triggernometry @auweatherwatcher @emilyyyZzz They are girls and we call them so. We use such naming in common language. We do not have anonymous helpdesk, but we have Kori and Petra ...and unlike Alexa or Siri, they are real ;-)
RE: And yes, we can...
This topic seems to be explosive. I understand that many people are against
"global warming religion", but think about it pragmatically.
If we call "Warming" the situation when "climate is changing rapidly and it is caused by mankind",
then there are 4 options:
A. Warming is not true and we believe it is not true
B. Warming is not true and we believe it is true
C. Warming is true and we believe it is true
D. Warming is true and we do not believe it is true
If we want to do any action we should behave pragmatically, economically, rationally.
Consider the damage control. There are 2 faults among these options: B. and D.
If B. is our reality we may waste our energy and money uselessly and our children will laugh at us in future.
If D. is our case, it means that we are borrowing our wealth from future generation, our children will hate us.
From this point of view the "panic" about Warming is completely understandable.
If we think about what is caused by humans: Daily weather is caused by humans. If you live in big city,
the temperature, moisture, evaporation, albedo, everything is massively influenced by human and you can measure it.
If you look at countryside from air, you can see that the terrain is completely changed by human. It also affects daily weather.
People have power to change the landscape, to destroy or plant whole forests.
Greenhouse hypothesis is about composition of atmosphere. I do not want to judge whether that hypothesis is true
or false. But people are moving fossil fuel from land to atmosphere. That is fact. One day all fossil fuel
will be moved from land to atmosphere, it will not magically disappear.
50000kg of airliners fuel means exactly 50000kg of waste. It is taken from land and put to air circulation.
Rising temperature is reality. Question is: Is it caused by our technical revolution? Nobody is sure, but there is correlation.
Do not cry, do not panic, just think about A, B, C, D.
RE: Despite premium subscription, ECMWF updated 10 hours ago...
@MolnAir Hi, we are sorry, this was a fault on our server, not a problem on ECMWF side. We had difficulties with data importing, so there remained the old forecast. Everything is up and running now.
On Premium subscriptions: we are trying to find a balance between keeping most of the features free and giving good added value to premium users. A year ago there were just donations (no added value for our contributors). This year we came up with better temporal resolution of the forecasts and it is likely that we will be adding more premium features or maybe shifting some existing features to premium to keep the product attractive for our subscribers. We are developing Windy for people and we are happy that a part of them (like you) is willing to pay for it. Thank you!
Latest posts made by TZ
RE: Arome model for Indian Ocean ?
@Windplayer Hi! Thank you for your request, it sounds interesting! We will consider it. There are multiple models in queue to include in Windy, but if there are more people demanding this one, we can give it a higher priority. T.
RE: Delayed ECMWF data
@illili Yes, and this is "the single data centre" :-) https://www.ecmwf.int/en/newsletter/170/computing/ecmwfs-new-data-centre-italy
RE: Your animations
To download this video just click with right mouse button on this link and select "Save link as..."
This video is licenced under Creative Commons licence (CC-BY 3) and can be used/modified freely in any possible way. Just mention Windy.com
Create your own animation at https://www.windy.com/animate
RE: The UKV Met Office model is now available on Windy
@EmmanuelC Hi, so far only ECMWF is available for route planning and it is not on our todo list to add other models in the following weeks or months, but we will discuss it internally. On the contrary, adding a route planner into mobile apps IS on our todo list ;-)
RE: The UKV Met Office model is now available on Windy
@idefix37 Yes, it has been fixed by using better data. The difference in coverage is as follows:
RE: Tide Forecast on Windy
@SVFLIGHT @William-Cane @roadrunner40 @BlueMovement @Clark-Pine thank you for your interest in Tides. We considered it just a supplementary feature over the time. I am happy to read that you are using it. It seems that we should give it some facelift :)