Frequently Asked Questions

What is RadarScope?

RadarScope is a specialized browser for the National Weather Service's NEXRAD Level III public data feed.

What does it do?

It retrieves the latest available data from NOAA's NWS server for a single radar site and displays it on a map. It can display base reflectivity, base velocity or storm relative velocity data at the lowest tilt angle.

What does it not do?

It does not provide a a broad national overview of all precipitation in the US, or what are called radar mosaics.

Who is it for?

RadarScope is for weather enthusiasts, meteorologists, or anyone who has an interest in weather radar. We come from Tornado Alley, and RadarScope at its roots comes from a meteorological background. That's not to say it's only for meteorologists (it's not), but it's not necessarily the same thing you see on your evening news (except maybe if you live in Tornado Alley). Showing an image of where precipitation is falling is sufficient for most people, and there are no shortage of websites that can give you that information, and even other native iPhone apps do a great job of showing radar mosaics. RadarScope is designed to do more than that, for those that need more detail, more flexibility, and more than just precipitation. For example, most people probably have no need to look at Doppler velocity data, but for those that do, they understand that it's not the type of thing you've been able to do on a mobile platform like this before.

Does it work for Puerto Rico?

Yes! RadarScope 1.4 adds support for the San Juan, Puerto Rico radar.

Does it work for Hawaii, Alaska, or Guam?

No. Currently RadarScope only displays data for radar sites located in the lower 48 states and Puerto Rico.

Does it display animated loops?

Yes. RadarScope can download and animate over the latest six frames of data.

Where do the data come from?

The radar data originate from NOAA's network of WSR-88D NEXRAD radars and are in the public domain. RadarScope can obtain data from NOAA's NWS data feed at weather.noaa.gov. Please refer to the NWS data disclaimer for more information. (http://www.weather.gov/disclaimer.php). RadarScope also includes support for commercial data feeds, so you have alternatives for getting data.

Why does it say "Image is X minutes old"?

When the data start to become stale, RadarScope will alert you to this fact with the above status message.

This can be for any number of reasons: Sometimes the radar is down for repair or maintenance, sometimes the server may be slow, etc.

If the radar does not update for an extended period, go to the application settings and tap the View Support Page button. Our iPhone-optimized support page includes radar status messages that indicate which radars are currently offline and may provide additional information about the problem. You can also check http://weather.noaa.gov/monitor/radar/ or http://www.weather.gov/view/validProds.php?prod=FTM for radar status. Those pages will give more details about what exactly is going on and when you might expect data to start flowing again.

Since RadarScope uses publicly available data feeds from NOAA and our commercial providers, and their servers are subject to slowdowns and heavy loads, unfortunately there can be no guarantees for data timeliness or availability. Please see the disclaimer on the NWS website (http://www.weather.gov/disclaimer.php) as well as our Terms of Use.

Why does it say "Cannot contact server"?

RadarScope cannot establish a connection to data provider you've selected, therefore it cannot get data to display. Please see the disclaimers on the NWS website (http://www.weather.gov/disclaimer.php) and in our Terms of Use regarding data availability.

What is different between RadarScope's display and the images available on radar.weather.gov?

RadarScope uses the raw Level III data to generate an interactive display that you can zoom, scroll, etc. Since it uses Level III data, the display is in the true radial format of the radar, which is beneficial for its resolution and compact size. The images you see on the radar.weather.gov website are static and can't be explored in the way you can in RadarScope. The data that RadarScope downloads from the NWS is surprisingly compact, which is great for those on the go.

How often does it update?

The NWS updates the data every 5-10 minutes, and RadarScope intelligently checks for new data on a similar schedule being mindful of extraneous network activity and battery life.

Why doesn't it update more frequently?

When a radar is in precipitation mode, the radar transmits updates usually every 5-8 minutes. In clear air mode, the updates are about every 10-12 minutes. When the data you're looking at are fresh, RadarScope doesn't bother checking the server again until it's likely that an update is available. When the product you are viewing becomes more than five minutes old, RadarScope begins polling the server once a minute to check for a new product. It could check for data more often, but that would drain your battery more quickly.

Does the sweep animation indicate refreshed data?

No. The sweep animation is intended to depict the coverage area of each radar to help you determine which radar best covers your area of interest. It is not an indication of refreshed data.

The radar buttons and "sweep" animations on the map are distracting. Is there any way to hide them?

Yes. Touch the "Change Radar" button, which is the second button from the left in the toolbar, to show or hide the radar buttons and sweep animations.

Hey, what's the deal with all this ground clutter I'm seeing?

When there is no precipitation in the area, it's very common for the radar to be operating in what is called "clear air mode". When in this mode, the radar is operating more slowly so that it can be more sensitive and pick up weaker returns (and hence more clutter). But why would it do this? Why would you want to see this?

Clear air mode gives it the ability to see things like flocks of birds, insects and bats, but for meteorologists it provides the ability to see things like cold fronts and subtle airmass boundaries. When conditions are right, these boundaries can become the focus point for storm initiation, so being able to see them is extremely useful.

Clear air mode is also useful for detecting very light drizzle and light snow. Sometimes these phenomena do not generate a strong enough return signal to be detected in precip mode, but stick out like a sore thumb in clear air mode.

You can think of the two modes, clear air and precip mode, as opposite ends of the same scale, with clear air mode on the low end and precip mode on the high end.

To the uninitiated, clear air mode may just look like useless ground clutter, but in that data can lie very important hints about what the atmosphere is up to.

Here's an example of a radar in clear air mode. You can see the bands of light drizzle to the east, which are approaching levels that would trigger a switch over to precip mode by the radar operator.

What is Doppler radar?

A great place to start learning about Doppler radar is at http://www.srh.noaa.gov/radar/radinfo/radinfo.html. Additional information is available at http://www.srh.noaa.gov/jetstream/doppler/radarfaq.htm

Does RadarScope collect any information about me or my phone? Does RadarScope engage in any network activity that could violate my privacy?

RadarScope accesses radar data via static URLs on web sites operated by NOAA's National Weather Service and our commercial data providers. If you click the "Visit Web Site" button on the preferences panel, RadarScope will load a help page from basevelocity.com. RadarScope also contacts our web server to obtain radar status reports.

If you are a member of the Spotter Network and you choose to report your location to the Spotter Network, RadarScope will send your location information to the spotternetwork.org web server every two minutes.

RadarScope collects statistics on how much radar data you download and reports the total number of bytes downloaded to our web server not more than once a day. We plan to use this information to determine total bandwidth usage by RadarScope and determine the overall impact on the servers from which RadarScope obtains its data. This information will help us plan for new products and services in future versions.

We respect your privacy as much as our own. We don't collect any information about you, your phone, or how you use our software aside from that documented above. It's conceivable that future versions might include features that require the collection of usage patterns or other information directly related to the use of the software. If we decide to offer such features in a future release, we will disclose it to you.

What features are you going to add and when will they be available?

We have many feature requests, and we are continuing to support and improve RadarScope. Because of the uncertainties associated with software development, we prefer not to make commitments regarding new features and when they might be available.