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Understanding Radar Images


physichull

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Hello NetWeather Community,

This is my first post, so go easy! I am an absolute novice when it comes to weather but have a strong physics background, a keen interest in weather and have been trying to do a lot reading around.

The internet is a great source of advice and I have found this website of particular use http://ww2010.atmos.uiuc.edu/(Gh)/home.rxml as a beginners learning aid. It's a little dated but it does the trick for the most part.

However, what I have struggled to find is a comprehensive guide on reading weather radar programs. Currently I have downloaded the trial version of GRLevel3 and I have found it fascinating whilst watching the weather patterns around Isaac. This morning I have looked at the weather radar warnings and found a Severe Thunderstorm Warning in place in parts of Iowa, USA. I have been recording the data for a while now and have posted a screenshot of one of the latest images, including Base Reflectivity and Velocity. I understand the fundamental principles behind these two images, however I struggle to interpret quite what is going on with it, or indeed in judging whether it has the tornadic(?) potential. I am am also curious as to what the two light green bands are to the south of the storm and what they could mean. They appear to be sucking towards the east of the lower hailstorm icon, is this the correct interpretation? If so, is that creating circulation winds that could potentially form a tornado, or do I completely not understand anything about what I am seeing! (very probable!).

What would really help would be if somebody could take the time to just run through a few features of this storm, the line of red, the precipitation to the north west, the velocity, the two green bands to the south east and its tornadic potential (if any). Thank you in advance.

Iowa_050912.jpg

Additionally, I realise this may have been covered countless times in previous topics, but I only really stumbled upon GRLevel3, but would anyone recommend this software as a radar viewing tool for the US?

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Posted
  • Location: Burgas, Bulgaria
  • Weather Preferences: Severe summer weather, winter extratropical cyclones
  • Location: Burgas, Bulgaria

It seems that a squall line is being tracked on this radar image. For further analysis and interpratation I must see the radar loop, but this is what I think at first glimpse. The squall lines are characterized by a very strong reflectivity on the leading edge, a transition zone just after it and a stratiform precipitation area. For it to be initiated, there has to be some linear forcing mechanism such as a dry line or a cold front. You must look close at the CAPE and SHEAR values to determine what the most likely structure would be.

About the tornado question: It is basically found in supercells : convective cells which possess a rotating updraft. It has a mesocyclone and there you can most probably find wall clouds or a tornado.

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Thank you for the replies. I clearly have a very long list of questions and a muddled up order of answers about meteorology in general thatI am trying to sort out but hopefully this forum and the internet will help me through it!

I saw a simlar storm system with much stronger winds the other day, it got tornado warned but I think it was mostly down to the people on the ground observing fallen tree's etc, rather than evidence from the radar. It seemed as though the tornado warning came from reports rather than science. I guess that's just the way it goes sometimes.

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