House Calls


On the level: clearing up radar data misconceptions

When you subscribe to AllisonHouse, depending on the package you buy, you will get Level 3 radar data, or both Level 2 and Level 3 data. Some people may come to the conclusion that super resolution data is Level 2 data, and Level 3 is not. Let’s examine what each one is, and what it does.

First, yes, there is Level 1 data. Level 1 data is unprocessed, raw data. You may think “that’s what I really want!”. In reality, you don’t. The unfiltered, unprocessed data actually contains issues that are processed and fixed in level 2 and level 3 data. You would see a lot more noise, and a lot less signal, in this data. It would considerably harm more than good, for nearly all of our customers. It isn’t distributed to anyone outside of the National Weather Service.

Level 2 data has what has come to be called “super resolution”, or 250 meter resolution for velocity, and 1/4 km resolution for reflectivity. Close to the radar, the resolution is higher, but the data is averaged when the resolution is higher close to the radar. In any case there is some processing that occurs: some buildings and some false returns that are always there are filtered out or reduced in magnitude (reflectivity from wind farms cannot be eliminated, unfortunately, because real echoes would be filtered out as well). You get base reflectivity and velocity at all tilts, along with spectrum width, as the radar scans,

Level 3 data is more processed. First, because of bandwidth issues (more on this in a moment), the resolution of reflectivity data is reduced to 1 km, and 1/2 km for velocity data per pixel. You also only get the lowest 4 tilts of the storm. This is why you cannot generate a 3D view of the storm using level 3 data…you can only see 4 “slices” of any storm. But, you also get a lot of processed and derived products, such as:

1 hour, 3 hour and storm total precipitation estimate
Vertical integrated liquid
TVS signature, mesocyclones, hail indicators, storm relative velocity

And a lot more.

Because of all the derived products, and because each radar site only has so much bandwidth, they cannot send everything out at full resolution. So, a lot of these are sent at high resolution, but not at “super resolution”. Sending out the data has bandwidth concerns, as is limited capacity on the satellite feed they uplink the data to, known as NOAAport. That’s the feed the National Weather Service offices (and AllisonHouse) get the data from, in real time.

But, did you know that there are super-resolution base reflectivity and velocity products in level 3 format that are sent to the National Weather Service in Washington, DC? The issue is that you *can* get these products, for a nominal fee of about $120,000 a year. AllisonHouse has decided not to pay that fee and get those products because:

1. The super resolution data only goes out to 124 miles
2. It’s already available with Level 2 data, and that goes out to 248 miles
3. The latter is sent via fiber, not via satellite, and through cooperative agreements, we are able to provide you this data at a reasonable price.

But you might ask: I want my cake, and eat it too! What are the chances of us getting level 3 super-resolution base reflectivity radar and velocity data, even if only out to 124 miles?

Well, the answer to that is: maybe. A few years ago, the National Weather Service infrastructure, from the satellite feed, to their Web server farms, and internal routing couldn’t support it. Over the past few years, major upgrades to their web farm and a major speed increase to the satellite feed now make it worth discussing. And, in fact, they are discussing transmitting it to the public (and AllisonHouse!), and how to archive it as I speak. So, while it won’t happen tomorrow, there is a chance that it will be available in the future. And AllisonHouse will, of course, keep you updated if any additions are made to the National Weather Service data feeds.

But, here’s the good news: with AllisonHouse, you can have your cake, eat it too, and we’ll keep giving you as much cake as you can eat! By the cost of a family pizza per month, you get all the site radar data you need: Level 2 super-resolution AND level 3!. Just get our Storm Hunter subscription, and you’ll have the complete Level 2 and Level 3 feeds to your favorite software. And, you’ll have the most powerful information to make informed decisions right at your fingertips…all of this without chocolate, raspberry cream or banana cake all over your fingers. Bon Apetit!

“Southwest Canada is on fire”

Image of Canadian forest fire locations

This map, courtesy of the Canadian Wildland Fire Information System, shows the number of large forest fires occurring as of July 11, 2015.

 

MODIS imagery of smoke in Canada

This MODIS imagery, viewed from AllisonHouse Maps,  shows the large plume of smoke, indicated by the arrows, heading southeast from central and western Canada into the northern U.S. This has caused poor air quality and breathing problems to some in the Great Lakes, and major evacuations in Alaska and Canada. Image taken on June 30, 2015.

That comment came from a friend on my Facebook page. And it’s not just there, unfortunately. For those of you who live in the northern, and parts of the central and eastern U.S., you know the drill: blue skies aren’t anywhere to be found. I’m not talking about a lack of clouds. I’m talking about the massive forest fires going on in early July across Alaska and Canada, causing skies to go milky white and block out the sun as far south as Tennessee.

Some think this pattern might be El Nino related, but in any event, the jet stream orientation in June and so far in July has taken a route from central Canada, southeastward into the northern and northeastern U.S. That has been responsible for cool to unseasonably cool temperatures in the Great Lakes. However, it’s also sent the smoke with it down into the U.S. as well. In part, the dense smoke is also blocking a significant to substantial part of the sunlight from getting through. Here where I live in the Chicago area, on one particular afternoon, it was like a dense cirrus cloud overcast was covering the sun. In reality, it was smoke, as high as 18,000’…getting into the jet stream and pushing southeastward into the Great Lakes and Ohio Valleys, as well as parts of the northeastern U.S.

Lightning-induced fires from “dry” thunderstorms (whereby the rain evaporates before hitting the ground, but the lightning does, igniting the fires) continues to plague southwest Canada as their monsoon season begins. It does not look like this will end soon, as the general jet stream pattern is expected to remain the same.

MODIS imagery, now available on AllisonHouse Maps, shows the smoke incredibly well. You can clearly see, in areas that are cloud-free, the source of the smoke, and its track southeastward into the northern U.S. Thanks to mixing, that smoke is coming back down to the ground across Wisconsin and Illinois, resulting in poor air quality and numerous alerts to those who are prone to allergies or irritation. Even though that is not a good thing, obviously…it isn’t anywhere as bad as Canada and Alaska, where people are losing their homes. At times, visibilities have been reduced to less than 5 miles in some areas of the Great Lakes. We here at AllisonHouse pray for a swift end to these fires, and strength and comfort to the firefighters, and residents in Canada and Alaska affected by them.

Austin Straubel International Airport. Say what?

Hey AllisonHouse fans,

For those who use the Gibson Ridge placefiles, and GREarth, this past weekend I realized something, and it wasn’t good.

Several years ago, we had a database crash, and we lost all our METAR site locations. Every last one! Starting from scratch, we decided to download the FAA and two other databases that have all the sites in them, and merge them. This generally went OK. But it had an obvious problem: Many of the FAA METAR sites in the United States listed their airports, and not the city that they were in or served. Or, they did a poor job of doing so. And so, late last week, I saw a METAR site near Green Bay that said that it was “Austin Straubel International Airport”. Huh? It took me a minute to figure out that…yes, that was Green Bay, WI’s primary airport. And as I moused over other sites, I saw things that embarrassed me, as keeper of the database. “Wst Chgo DuPa” was West Chicago / DuPage County Airport just west of Chicago. Like you would know that, unless you lived there!

So: this past weekend, I added the city names out in front when you mouse over them. I might have missed one or two here or there, but I got as much done as I could. Also, if I missed one of your favorites, please let me know, and I will add them in. With some airports, they just prefer to be called by their city name, minus the word “airport” at the end…so I left it at that, for now.

I hope you enjoy the enhancement…and now, back to your originally scheduled squall line, already in progress.