Tuesday, December 30, 2008

Thank you: Menno van der Haven

Thank you Menno for posting the information bellow. The tornado was on 6 June 2005. I will soon write more about the meteorological conditions of that day.

A dialog between MJ Poore and Menno van der Haven on a forum of passionate meteorologists:

" 06-27-2007, 01:27 PM

Good point about Eastern Europe Menno. Some say Romania and Hungary have the highest incidences of tornadoes in Europe and that's a recent observation, because people didnt know about them before. The two counties have some of the best geography in Europe to get big storms going. I see Romania even has a US style doppler radar network now. But exactly how many they get, and how strong they are, I dont know.


You are right about that, MJ Poore,
Two years' ago I was in Romania and I was lucky to watch a tornado near Tirgu Mures. However, the locals didn't believe me when I told them that I had seen a tornado in their area. They said: oh, that were rain-curtains. Only when I showed them this picture:
they were convinced ;)"

Monday, December 29, 2008

ECSS - 2009

The 5-th European Conference on Severe Storms will be held on 12-16 October 2009 in Germany, Landshut. Is a place where we all speak the same language, of storm-fans, and the atmosphere is very "instable" and "triggers" great friendships and actions.

Saturday, December 27, 2008

Convective cell: What radar sees

This is a very nice photograph taken by an astronaut while leaving the troposphere. Visual we can identify the overshooting, as a sign of strong updraft, the anvil, where the level of equilibrium of the air parcels lifted from the ground is, the very instable air that hangs is the altitude, on top of the updraft, where hail forms, sometimes as mamatus clouds. The overshootings are also very nice to be seen on visible channel satellite pictures, as satellite looks from up, down to the top of the clouds.

In coloured lines I wanted to show what a radar would see if would scan this cloud on vertical cross section, as reflectivity. The radar sees only a part of the cloud, but the most instense, that has more water and bigger particles (rain drops, hail, snowflakes). More than this, can see it from quite a long distance, and on 360 around the antenna.

The radar can track (see the evolution of) these cells and "tells" in time to the pilot what to avoid. What can happen if he gets into the updraft? He would be very lucky if he would remain alive and the aircraft would be destroyed by strong turbulence, big hailstones, thunders, iceing.

Friday, December 26, 2008

Nowcasting Symposium 2009

The International Symposium on Nowcasting and Very Short Range Forecasting (WSN09) will be held at the Tellus Conference Centre in Whistler, British Columbia, from 30 August to 4 September 2009.

This meeting is organized by the World Weather Research Programme (WWRP) of the World Meteorological Organization (WMO) and will be hosted by Environment Canada. The previous Symposium (WSN05) was held in Toulouse, France.

For further information seehttp://www.nowcasting2009.ca/ (this web site is also a great source of training material).

Thursday, December 25, 2008

Radar images for Central Europe

Enjoy this link: Radar images in EC

Radar Errors and Limitations

(more details on JetStream - great generous site for the public!!!)

Radar is a detector that has its limitations, first of it is the ... fact that the Earth is curve while the beam propagates with a smaller curvature, so, the beam is bending upward with the distance. Further the echoes are on the screen, the higher is the sample! (you can use the graphic above to have an idea about this variation).
But this has a great advantage in... the wind field. It enables us to see the wind shear (how wind changes with height) in a single glance (some details here:
And this is the real advantage of Doppler radar in front of other detectors because the wind shear actually controls the severity of a convective development.

Radar is all a trade, or better say that learns you how to change the weakeness into a strength.

Tuesday, December 23, 2008

Carpathian Convergence Line

This time was seen only by the satellite, the clouds developed were not stromg enough to be detected by radar (in summer this situation can bring severe storms).