Convective Weather Maps now automated

[Oscar van der Velde]

Since February 2002 I've been producing a line-up of plots of parameters useful in severe weather forecasting for Europe and North America, using data from the GFS model. This was always done by manually downloading the data usually once or twice a day, running the GrADS scripts on them, and uploading the images to my website.

Convective Weather Maps

I am very happy to announce that as of today, the maps run automatically on the ESTOFEX server, four times a day, out to +72 hours in steps of 3 hours. Both for Europe and North America (excuse me for leaving out Alaska and northern Canada).

This means you will have a new source of reliably updated maps (if everything keeps running fine). Of course, the GFS model isn't really an ideal model for forecasting convection, but over these years I found by looking at a variety of parameters it usually gave me a very good impression for future convective development. An issue with the model of overforecasting near-surface dewpoints and resulting CAPE values is circumvened by not using the near-surface values. It tends to be a bit on the conservative side now.

Enjoy them! Suggestions are always welcome.
Oscar


PS 1. For some more info, see this earlier thread
PS 2. My favourite for North America is the mixing ratio loop. We don't see these things in Europe!

Edit 4/28: Maps update correctly now.

 

[Tom Stefanac]

Awesome work!

(excuse me for leaving out Alaska and northern Canada). [/b]

Well I can't say anything about poor Alaska, but you got the parts of Canada which matter in terms of severe weather.

The loops are great and the colours.. I mean colors :lol: are awesome!

Amazing work!

 

[Alex Lamers]

Excellent work Oscar and thanks much! I am always wary of the GFS underestimating some of the thermodynamics but I will certainly use it. Does your convective gust potential factor in how well mixed the boundary layer is? If so the GFS always seems to perform poorer than the NAM in this department and thus I would expect the values to be biased a tad low.

By the way, keep up the good work over at ESTOFEX...its good to see convective weather forecasting somewhere other than the US. I would be interested to see some outlooks out of Australia too. I stop by every once in awhile to see if any severe weather is pounding our European friends.

 

[Oscar van der Velde]

Excellent work Oscar and thanks much! I am always wary of the GFS underestimating some of the thermodynamics but I will certainly use it. Does your convective gust potential factor in how well mixed the boundary layer is? If so the GFS always seems to perform poorer than the NAM in this department and thus I would expect the values to be biased a tad low.
[/b]

There are in fact 3 parameters in that map. One is simply the mean 900-600 hPa wind speed which more or less could be transferred to ground by convective downdrafts. This does not take into account the stability of the boundary layer. I once had the 'Ivens' gust method, developed at the KNMI, Netherlands, as a statistical regression formula using several levels... but also e.g. 200 hPa jet. Not very physical. Didn't work very well for me. But that one used different formulas for stable vs. mixed BL.
The cold pool strength (or downdraft lifted index, i.e. a 'sunken index', if you want) does give you an idea, high values usually occur due to steep BL lapse rates. The values decrease at night.

By the way, keep up the good work over at ESTOFEX...its good to see convective weather forecasting somewhere other than the US. I would be interested to see some outlooks out of Australia too. I stop by every once in awhile to see if any severe weather is pounding our European friends.
[/b]

Thanks, we will certainly keep doing this... hard to spend the time sometimes since it's not our job. This is especially true for making progress towards becoming a more serious and recognized 'institution'. Pieter Groenemeijer has now advanced quite well with developing a digital map polygon drawing tool that saves the coordinates, so that we can then use those and severe events or lightning locations to make a verification. This is when it starts to become really interesting.... it should be fun to see FAR, POD, etc. stats per forecaster, per area, season.... but again, all of this programming in our limited free time besides our other personal activities, so advancing just slowly.

Oscar

 

[Oscar van der Velde]

I diverge from the topic of the weather maps, but:

Well I can't say anything about poor Alaska, but you got the parts of Canada which matter in terms of severe weather.
[/b]

In early summer 2004 I've been in Alaska, and it was quite convective, mostly orographic thunderstorms. They caused the many forest fires together with the hot, dry weather (lower 90s - in Denali National Park all the animals were hiding somewhere in the shade). I spotted a distant landspout. Before I arrived, probably 25/26 May 2004, people reported several landspouts touching down near the airport of Fairbanks.
It is interesting to see what the long daylight period in summer at these latitudes does to the daily cycle of storms. I think I noticed two maxima during one or two days, one around 4 pm and another weaker one some hours later, in the evening, after the limiting remaining cloudiness has been slowly burned away and the boundary layer had recovered a bit - but mostly this would yield shallower convection only. Would be interesting to see some statistics on this 'boreal convection'
In these parts you have not much road options if there would be a a storm worth of chasing, let alone that there are so many trees (and musquitos) that you usually can't see the landscape and distant storms... <_<

Oscar

 

[David Shohami]

Thanks for the maps!
Do you think you could expand the east and south a little bit so that southern Israel and Sinai are included? If it's a problem then this is also fine.

 

[Oscar van der Velde]

Thanks for the maps!
Do you think you could expand the east and south a little bit so that southern Israel and Sinai are included? If it's a problem then this is also fine.
[/b]

I don't plan to include much more - what you see of Israel is as far south as I download the data crop (30 North), I can try adding just a degree more to the east. I'm running the maps on Pieter's downloaded data at ESTOFEX. The USA data is my part. In fact, you can just see Eilat in the extreme corner

I've been in your country for six days in December to help the University of Tel Aviv's sprite observation campaign - no luck then, but January - March they caught them (maybe you know: ILAN sprite observations)

cheers,
Oscar

 

[Bill Hark]

Thank you very much for adding the model output pages for both Europe and the United States. That must have been a lot of hard work. Very good graphics and easy to use.

Bill Hark

 

[David Shohami]

I've been in your country for six days in December to help the University of Tel Aviv's sprite observation campaign - no luck then, but January - March they caught them (maybe you know: ILAN sprite observations)

cheers,
Oscar
[/b]

Wow, neat site! It's the first time I see it. Thanks!