Author Archives: HansR

New normal values

In 2021 the Dutch Meteorlogical Institute (which has the predicate royal, koninklijk in Dutch, hence KNMI) started using new normal values. Something they do every 10 years shifting the normal to the most recent three decades.

So from the first of january the normal values are calculated from the years 1990 until 2020 (included). However, the KNMI only publishes the normal values for their official numbers i.e. De Bilt where their office and main weather station is.

So how do I follow? How do I get my normal values for Wagenborgen which is some 175 km north east of De Bilt as the crow flies. The nearest official KNMI stations are Nieuw Beerta and the Airport Eelde. Usually I use Nieuw Beerta for my temperature and humidity calibrations but unfortunately, Nieuw Beerta does not measure rain.

As Airport Eelde is more land inwards, the temperature will likely deviate from Nieuw Beerta so I made the choice to create the normal temperatures from Nieuw Beerta and the normal rain values from Eelde.

I took the values from the daily KNMI measurements page: rain for Eelde and Temperature for Nieuw Beerta. Then I wrote a short program to read the output and calculate the resulting normal values for monthly temperatures and monthly rain. The resulting values I filled in in the CumulusMX settings for the NOAA reports from where they are fetched to be used in the CumulusUtils reporting style you see on the website.

The new normal values used for my Wagenborgen weather station for the period of 1990 – 2020 are shown in the following table:







For the first time in a long time we have snow. For one day – it will melt around noon – and only one to two centimetres, but nonetheless it is always breathtaking to see the world change overnight if you are not really accustomed to snow.

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Air Quality sensors on the Raspberry Pi

On the 7th of April 2020 I wrote about the Website Generator of CumulusUtils. That appeared to be somewhat bigger than I expected, simply because it was about a full blown website with users interacting. And interaction generates comments. All has now stabilised and CumulusUtils works fine. 

Meanwhile, on the background I had been working on a project to get going with air quality sensors like the PMS1003 ($14,20 at AliExpress) or similar cheap serial devices. In the back of my head always has been the creation of a multi sensor ‘sniffing’-centre to get a complete overview of the local airquality. Something worthwhile: I grew up in the neighbourhood of Rotterdam/Pernis an area known for its bad air and now I live south of Delfzijl, a small harbour in the North  of the Netherlands with relative big industry area. 30 km North from there there are two large coal power plants and smog condition occur several times per year, though not often.

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About pwsFWI

pwsFWI is now a bit more than a year old and has proven its value : it relates very well to the existing indices and the EFFIS Current Situation viewer. This means that the note : Behavioural testing still under way! will be removed from the pwsFWI page at the end of the European fire season (21 September).

Having said that, I have noticed that some users have reverted to the FWI calculations and graphs as shown by FWIcalc  as if that one is better than pwsFWI.

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On PyroLife ITN, Tecnosylva and Wildfire Analyst

This is a short blog on some fire related research and organisations. Unrelated directly to pwsFWI but definitely useful to follow if you are interested in fire – wildfire and/or society related issues regarding large wildfires. Especially the running webinars are interesting (and free) !

Recently (in  2019) an ITN project PyroLife started (what does ITN stand for btw?), led by Wageningen scientist dr. Cathelijne Stoof.

Apart from being a great initiative, it became quickly very interesting because of the free webinar which started 3 June 2020 (and running till the end of july 2020). The presentations of this Symposium are published on the YT channel of PyroLife (don’t start binge watching these presentations, prevent overkill).

I would like to point to the the presentation of Adrián Cordil of 10 June 2020 (at moment of writing not yet published) on thePyroLife YT channel linked above, scientist at the University of LLeida, Spain and associated with Tecnosylva S.L. (twitter account). He presented the work of Technosylva regarding simulation software, put to work in different parts of the world in the context of combatting wildfire situations.

Estimating Fire Weather is one aspect of this. An interesting piece  of software to look at is Wildfire Analyst also available for Android. Check it out.

pwsFWI is unfortunately not related to this [large] project, but the results of your weather  station, and your understanding of meteorology, definitely might give you an entry to understanding what they are doing there in Spain.

Change of release post on Cumulus Support forum

Since 21 april 2020 CumulusUtils has its own subforum on the Cumulus Support forum. That makes things clearer and creates better oversight. However, many links in the blogs before that date contain a link to the old release topic. I did change some recent ones but left the older topics untouched. If you encounter such link, remember to go here and not there.

On the programming of CumulusUtils (2)


More than 6 months ago, I wrote a blog  on the how and why of the programming of CumulusUtils. It is time to do that again because in 6 months, over the winter and now deep into the Corona Virus crisis, a lot has happened with CumulusUtils. When I wrote the first blog, it was mainly about the inspiration and development of pwsFWI. And it still is the most important module of the whole program (at least, it is for  me). But while working on pwsFWI and seeing where it was deployed  triggered something. Beside having the pwsFWI, one needs to think about the weather. It is not just a black box, it is about understanding the weather and it’s effect on vegetation and animals (including humans). To understand the weather you need to look at the parameters, the measurements. Continue reading

Impact of anthropogenic climate change on wildfire

I designed and developed my Fire Weather Index (FWI) for Personal Weather stations (PWSs) starting with basic logic reasoning (wet wood does not burn), with scientific background and made it usable in the context of PWSs. I found a very interesting and confirming article from October 2016: Impact of anthropogenic climate change on wildfire across western US forests [1].

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Analysis of pwsFWI prediction


In my previous blog I described why and how the predictions on pwsFWI were implemented. Also I promised a short analysis:

We’re now in version 1.8.3 and it seems all to be working OK. The testing is back on the meteorological level, trying to find out how much a two day ahead prediction will differ from the actual calculation when the day has past.

In this blog I will show the results and try to interpret them.
Please note that this is not a scientific or even a full analysis as I am lacking the resources and the data for that.

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Predictions of pwsFWI


The past months I blogged several times about my Fire Weather Index for personal weather stations on the basis of Cumulus as data acquisition software. So if you’re new here and don’t know what pwsFWI is about, check out the previous blogs on the subject. Currently, pwsFWI is part of a small software package named CumulusUtils. This meteo website/blog is the home of the package which is distributed through the Cumulus support forum. If you have a weather station which can cooperate with Cumulus, don’t hesitate and get it, it’s free.

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