Understanding Radar & GR3

[Rob Wadsworth]

I have used GR3 for the last three month. The learning curve has been consistent - but at times I have found it hard to understand all f the parameters that the program employs.

I toggle between CR248 and BR248 to gather the basic view of the storm from my laptop and the Alltel tether. I have a rudimentary knowledge of how to read Base Velocity (BV). But which parameters are most useful to storm chasers vs spotters? That is a good question - IMHO.....

My eSpotter status doesn't mean that I must contain myself to merely looking out of a window, as I am responsible to report for the entire county. It was my choice to further the reach of my knowledge to provide better real-time reports to the County Emergency Manager. The NWS benefits from me to be in the right place at the right time so that my reports can be as timely and pertinent to their warning polygons...

If there are those who wish to instruct newbies - like myself and others - to the finer points of using GR3 and radar signatures - would be greatly useful and ultimately appreciated.

 

[rdale]

http://www.wdtb.noaa.gov has two EXCELLENT resources on radar interpretation. Take the DLOC class first, that has fundamentals. Then when you are ready, take the AWOC.

All the webinars are archived so you get to watch and listen at the same time, whenever you want. There is a TON (ton) of documentation that goes along with it.

I'm not sure I understand your question about radar data for spotter vs chasers?

 

[Rob Wadsworth]

QUOTE: rdale
......I'm not sure I understand your question about radar data for spotter vs chasers?

Thanks for that link. That is partially the question I asked; so I'll clarify...

What GR3 Parameter(s) would be most useful for storm chasing, and would using other parameters be more effective for reporting to the County Emergency Manager. Or - would you consider them all to be linked without differentiating

BTW - The "EM" does't know the difference between convection and a convection oven. The buck stops with me - as far as using radar, GR3, or the equipment to do on-your-own live interpretations. Strange as it sounds, EM's don't have to be proficient in meteorology - but true. I thought it was pretty odd - myself!

 

[rdale]

I don't think there's much to go with... You should report to your EM whatever you see outside your window, whether chasing or spotting. If an EM cares about what is on radar - he likely has some sort of radar display on his own.

 

[Christine Hudnall]

For myself, a good source to help me understand better I used:

http://www.srh.noaa.gov/jetstream//

For just doppler: http://www.srh.noaa.gov/jetstream//doppler/doppler_intro.htm

Hope it helps.

 

[Christine Hudnall]

http://www.wdtb.noaa.gov has two EXCELLENT resources on radar interpretation. Take the DLOC class first, that has fundamentals. Then when you are ready, take the AWOC.

All the webinars are archived so you get to watch and listen at the same time, whenever you want. There is a TON (ton) of documentation that goes along with it.

I'm not sure I understand your question about radar data for spotter vs chasers?

Hey Rob - great link, thanks for that!

 

[Chris Nuttall]

What GR3 Parameter(s) would be most useful for storm chasing, and would using other parameters be more effective for reporting to the County Emergency Manager. Or - would you consider them all to be linked without differentiating.

If you're out chasing or spotting, you don't need to be telling the EM how to interpret his radar. Remember, radar is a tool for a remote sensing. It gives us a picture of the storm structure, but nothing is more important than ground truth. A radar indication of golf ball hail can't verify a warning. Only a ground truth report can do that.

There really is no differentiating in what tools are useful for spotting vs. chasing. Both activities require the ability to interpret reflectivity and velocities (just to name a couple). Also, don't get caught up in all the pretty hail and shear icons that get painted everywhere when looking at the Storm Attributes Table. Red and green next to each other does not necessarily indicate shear. It could simply be velocity folding.

What you need to be able to do is recognize storm structure on radar. Learn what it looks like when storms go through their life cycles, then equate that with what it looks like outside. You'll be able to tell what storms are crap and what storms are worth watching.

If you're a good visual learner, the light bulb will come on pretty quickly. Reflectivity is basically a top-down view of the storm. I would recommend looking at some radar screen shots along with the idealized diagrams of supercells. Then, find a photo of an actual storm (that has a good documentation of what direction the photo is looking) and compare that with radar. Think of tilting that radar picture down where it matches the real-life photo. I'm not sure if I'm being very clear or not. It would be a lot easier for me to show you. I'll have to find some stuff I made for Google Earth that can demonstrate.

 

[Dean Baron]

i love talking about GR. I have had it for nearly 3 years and i have learned quite a bit about the accuracy of certain things. One thing i can tell you right off the bat, dont pay attention to the storm motions that GR gives you, most of the time they aren't correct, but instead loop the radar, this will give a pretty good idea of the storm's motion. Another place that is good for info is going to the owner's forums and reading around, lots of topics with good insight about different things that GR can do (and cant).
http://www.grlevelx.com/owners/

Do you have any specific questions about the program? just to narrow it down a little bit...

 

[Rob Wadsworth]

"...Do you have any specific questions about the program? just to narrow it down a little bit..." -Dean Baron

I started this thread with the hope that any newbies - like myself - could get instruction and voice problems that they may face. the GRX Forum page doesn't get the responsive replies that STORMTRACK does.

I believe that rdale and a few others gave some useful info to me, concerning basic reading of live radar from the NWS. If you want to give an informative use of Spectrum Width and its related parameters, I know I will be taking mental notes. Thanks!

 

[rdale]

SW is something to look at when you see extreme velocities... If SW is high - realize the numbers on the velocity maps may be very wrong. If SW is low, you can assume fairly smooth flow and accurate readings. If it's high, you might have rotation.

 

[Bob Hartig]

Rob, if you're looking for a responsive support forum dedicated to GR products, the place to look is GRLevelXstuff.com (not the same as GRLevelX.com). It's an excellent forum, with lots of input for any and everything GR, plus tons of color tables and add-ons.

 

[Aaron Anderson]

Hi everyone,

Another thing that I believe would be extremely useful is as you read and go through some of the tutorials that other members have mentioned is to go back and look at some archived data. A lot of time nothing reinforces your learning like looking at real data and situations.

I recommend going to the National Climactic Data Center (NCDC) where you can download past NEXRAD data for individual radar sites. Go back and download radar data for different events, such as the May 3rd 1999 Oklahoma City tornado. You can go by events you know of or use the Storm Events area of NCDC to look up tornado reports for your area or any other. Here are some links:

Storm Events NDCD
http://www4.ncdc.noaa.gov/cgi-win/wwcgi.dll?wwevent~storms

NEXRAD Data Inventory Search
http://www.ncdc.noaa.gov/nexradinv/

Find some tornado reports in your area then go back and download the radar data and study it. Find a day when a tornado was reported in your area and then go see if you can identify it on the radar data before looking at the location information on the Storm Events.

Looking at radar data at times when you know something was happening can help you see the patterns and signatures that you read about. This can help you know what to look for in the future.

Hope this helps!
Aaron

 

[Rob Wadsworth]

Thanks for all of the help and leads. You can be sure that I will be re-reading this link until I feel more comfortable with my ability to read/understand radar data. I definitely want to do a better job before the next season begins. I was able to hold my own so far - but must improve my skill.

It has been discussed by the NWS that they will be upgrading their radar systems to the 'dual pole' and 'phased array' systems in the next few years. I think they said that could be on-line as early as 2010. This creates an interesting dilemma for those of us who tether and use GR3 and a few other weather radar programs that interpret level 3 data. This new 'fangled' phased array systems are supposed to be able to far better in determining storm motions and progression. The NWS even went as far to say that spotters will need only verify what they were already well aware of - with this new 'Frankenradar'. Storm chasing is about to undergo a massive change in the ability to find the right storm. This could save gas, mileage on your vehicle, as busts may well become a thing of the past. Of course, it will take time for the NWS to get this on-line and work out the bugs, but if it is anything like they claim - this could well be the next quantum leap.
What do you think/know about all of of that noise/hype?

Q: Has Gibson Ridge software writers talked about the changing GR3 to account for the kind of data that level 3 will become by 2010 - or will they have to rewrite it or scrap it altogether for the new data protocol that it will need to interpret?

 

[rdale]

Level III (NIDS) data will not be changing with dual-pole. (Phased array is even longer off, and hopefully will change before then because it would not be a good idea to replace all the 88D's with a PAR system.)

Level II, hi-res data, will have some dual-pol output. And GRLevel2AE is already set to display that.

I'm not sure if you misunderstood the comment, or someone from the NWS overspoke, but dual-pole and MPAR will NOT eliminate the need for spotters. Won't change it in the slightest. It will make it easier to get people to the right spot, and hopefully will reduce false alarms, but no radar can confirm a tornado like the eyes of a trained spotter.

 

[Travis Stone]

Level III (NIDS) data will not be changing with dual-pole. (Phased array is even longer off, and hopefully will change before then because it would not be a good idea to replace all the 88D's with a PAR system.)


It is my understanding that Phased Array Radar would be more useful in a weather type situation than its current use such as miliatry. I admit that I dont know anything about anything related to this subject, so I ask why would someone not want to bolster the 88s with a par system. does not the par system have a narrow search band which would equal longer and more accurate search distance? Also the par would allow you to scan a specific storm or area and maintain the other degrees of scan? Just wondering, and figured I would get an answer here.