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» Online Classroom   » Marine Weather   » Public Discussion of Marine Weather   » Historical Weather Analysis

Author Topic: Historical Weather Analysis

 - posted August 29, 2022 08:17 AM      Profile for Morgan           Edit/Delete Post 

I'm looking to do an analysis with QTVLM and ECMWF ERA5 archived data for a given day/week with steps of one year dating back x amount of years. This would be in order to better predict and simulate the weather at that specific time of the year. I would use this for sailing regatta's and possibly time-distance record's

Attached is a link to the ECMWF resources, but the opening and I imagine operation of the .grib files is unknown to me. (format of the .grib files surely would be an issue)


I am using a MacBook Air M1 2020 version 12.4
and qtvlm 64 bits 5.10-14-p1

Any advise would be much appreciated.

From: RSA
David Burch

 - posted August 29, 2022 09:09 AM      Profile for David Burch           Edit/Delete Post 
First I would get the latest version of qtVlm... for now even take the latest beta. Then in a week or so they will have a new main build to download.

then at at this link

https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-era5-single-levels?tab= form

set up a free account if you do not have one

Choose u and v component of wind along with sea level pressure, then select the dates and lat-lon, choose GRIB output, then when the link appears download the file.

We have many videos on viewing gribs in qtVlm... which are crucial as there are several things to set up.. notably setting the time to match what the gribs cover.

see starpath.com then from the youtube video link, choose the qtVlm play list to find related videos.

for race or cruise planning in the next year or so, you might want to look into the Climate Forecast System (CFS) model. qtVlm can also display and route with that data.

We cover these topics in our online Marine Weather Course.... you can work through the course in the normal order or jump right in and ask instructors for help with your specific goals.

You can also download and do routing with CFS using LuckGrib for Mac or iOS. www.luckgrib.com/models he also explains online in the models section about the CFS.

From: Starpath, Seattle, WA
David Burch

 - posted August 29, 2022 02:13 PM      Profile for David Burch           Edit/Delete Post 
We also have a lot of info on use of Gribs in qtVlm in our qtVlm Cheat Sheet
From: Starpath, Seattle, WA

 - posted August 30, 2022 02:11 AM      Profile for Morgan           Edit/Delete Post 
The ERA5 work's well. Many thanks!

I will continue experimenting and try find some presentation techniques to better interpret the different routings

The Cheat Sheet is very handy indeed

From: RSA
David Burch

 - posted August 30, 2022 08:04 AM      Profile for David Burch           Edit/Delete Post 
If you start the routings all at the same time, after you convert the routings to routes, they are saved, and you can show them all at once and then move the time slider or time step button and you will see boats all start and progress along the routes together.

Under menu routes there is an option called Route Comparator... and there are other ways as well.

From: Starpath, Seattle, WA

All times are Pacific  
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