Category Archives: SKYWARN

Your wind speed estimate is probably wrong

And the Beaufort wind force scale is flawed, says storm data researcher

As an avid kite flier, I’m often out in windy conditions. More than once, on a particularly windy day, I’ve guessed at the wind speed, only to be surprised when a handheld anemometer shows a speed as much as 10 mph lower than I guessed. It’s easy to think the wind is blowing stronger than it is. And a recent scientific study proves that.

“Storm reporters overestimated the speeds of wind gusts—on average, by about one third of the gusts’ actual speeds.”

The resulting paper, “Quantitative Assessment of Human Wind Speed Overestimation,” appears in the April, 2016 issue of the Journal of Applied Meteorology and Climatology (JAMC). Its authors report that “storm reporters overestimated the speeds of wind gusts—on average, by about one third of the gusts’ actual speeds,” according to a report on the study in Eos . (Members of the American Meteorology Society may view the full text of the original, JAMC article.)

I learned in SKYWARN storm spotter training that if I don’t have an anemometer, I can estimate wind speeds based on what I see the wind doing, using the Beaufort wind scale as a reference. Supposedly, an estimate based on whether the wind is (for example) causing large tree branches to move (32 to 38 mph, according to the Beaufort scale) is more reliable than an estimate based on how the wind feels against my body.

That might be true, but Beaufort-based estimates are still unreliable, because the Beaufort scale is flawed, study lead author Paul Miller told Eos.

What’s a SKYWARN storm spotter to do? I’ve heard a National Weather Service (NWS) warning coordination meteorologist say many times that damage reports are much more valuable to NWS weather forecast offices than are wind speed estimates. Now that I know my wind speed estimates — even those based on the Beaufort scale — are probably wrong, here’s what I’ll send NWS instead; a detailed description of damage I see the wind doing.

I encourage my fellow storm spotters to likewise report wind damage, rather than estimated wind speeds.

Learn more about weather via podcasts

If you’re interested in learning more about weather and the weather enterprise – especially while driving, exercising or doing anything else when you might listen to music or an audio book – a number of weather-related podcasts might be worth your time.

A podcast is basically a radio talk show that you can play on a web browser or download to a portable device like a smartphone or mp3 player for playback at your convenience. Some smartphone apps will automatically download a podcast’s new episodes when they become available. Several interesting podcasts are devoted to weather and often cover topics related to severe weather. Below, I list a few I’ve listened to and found to be worth my time.

WeatherBrains

WeatherBrains is the granddaddy of weather podcasts. It has been producing a weekly panel discussion for more than 10 years. Led by well-known, Alabama TV meteorologist James Spann, the WeatherBrains panel includes other broadcast meteorologists and a National Weather Service meteorologist. The panel routinely invites guests who are experts on various weather-related topics. Find more information at www.weatherbrains.com or search for “WeatherBrains” on the Stitcher or iOS podcast app or on YouTube.

Tornado Talk

Two radio meteorologists who work for a company that provides audio weather services for radio stations created a weekly podcast called, “Tornado Talk.” Episodes have focused on a number of historic tornadoes as well as more recent outbreaks, like the one in Indiana and Ohio Aug. 24, 2016. Because this podcast is produced by radio professionals, it should be no surprise that the production quality is very high. Of all the podcasts to which I listen, “Tornado Talk” sounds the most like a documentary that you might hear on a public radio station. Learn more at www.tornadotalk.com. This podcast is also available on the iOS podcast app, Stitcher and Google Play.

Carolina Weather Group

Don’t let the title of this podcast fool you. It is not solely about weather in the Carolinas. Like WeatherBrains, this is a weekly panel discussion with several regular panelists. Panelists include two TV meteorologists, a commercial meteorologist, a storm spotter (who is also a ham, with call sign KD2AYM) and a college meteorology student. Like WeatherBrains, the Carolina Weather Group tackles a different weather-related topic every week, usually with a guest, and some episodes focus on severe weather. Learn more at www.carolinaweathergroup.com. Search for the Carolina Weather Group on YouTube and Google Play. I am not able to find recent episodes on the iOS  podcast app.

Weather Junkies

Two fairly recent graduates of the meteorology school at Pennsylvania State University host this weekly podcast. One is a TV meteorologist and the other is a graduate meteorology student. Like the other podcasts, the Weather Junkies invite a guest each week (often a fellow Penn State grad) to talk about a weather-related topic. Learn more at www.theweatherjunkies.com. Search for Weather Junkies on YouTube, SoundCloud, iOS podcast app, Stitcher and Podomatic .

Storm Front Freaks

This weather podcast launched in 2016. It is produced biweekly. Two of the regular panelists have meteorology degrees. Another is working on a degree. Others are storm spotters (like me) and storm chasers. Two of the panelists (also like me) are licensed amateur (ham) radio operators: Marc Johnson, KD0TCR and Mark Massaro, KD8RIS. Johnson’s bio indicates that he’s active with his local SKYWARN group. This podcast endeavors to be less technical than others and therefore more approachable to amateur weather enthusiasts. Like WeatherBrains, it includes a recorded educational segment. Learn more at www.stormfrontfreaks.com. This podcast is available on the iOS podcast app, Stitcher, Google Play and Tunein.

Weather Hype

Two graduate students joined the weather podcasting world in 2016 with this offering. Both have particular interests in social sciences and weather communication. They bill their program as “a podcast for casual weather conversation,” and an avenue to discuss important weather-related stories and educate listeners “in a very informal, unstructured way.” They occasionally involve a guest, but most episodes are just the two of them, presenting in a style that’s unique among the podcasts on this list. Learn more at www.weatherhypepodcast.com. Search for Weather Hype on Google Play and the iOS podcast app.

Half of Indiana has marginal risk of severe storms today

Indiana map showing (Left) Risk of severe weather between 9 a.m. EDT today and 8 a.m. EDT tomorrow. Dark green shading: Marginal risk. Light green: thunderstorms possible but none expected to be severe. (Center) Probability of damaging straight-line thunderstorm winds of 58 mph or stronger within 25 miles of any point. Brown: 5% (marginal risk). Unshaded: Less than 5%. (Right) Probability of hail of one inch diameter or larger within 25 miles of any point. Brown: 5% (marginal risk). Unshaded: Less than 5%. Source: SPC "Day 1 Convective Outlook" issued at 8:52 a.m. EDT.
(Left) Risk of severe weather between 9 a.m. EDT today and 8 a.m. EDT tomorrow. Dark green shading: Marginal risk. Light green: thunderstorms possible but none expected to be severe. (Center) Probability of damaging straight-line thunderstorm winds of 58 mph or stronger within 25 miles of any point. Brown: 5% (marginal risk). Unshaded: Less than 5%. (Right) Probability of hail of one inch or more in diameter within 25 miles of any point. Brown: 5% (marginal risk). Unshaded: Less than 5%. Source: SPC “Day 1 Convective Outlook” issued at 8:52 a.m. EDT. Click the image for a larger version.

Half of Indiana (shaded in dark green on the map, above-left) has a marginal risk of severe thunderstorms between 9 a.m. EDT today and 8 a.m. EDT tomorrow, according to the “Day 1 Convective Outlook” that the National Weather Service Storm Prediction Center (SPC) issued at 8:52 a.m.

The primary risks are damaging straight-line thunderstorm winds of 58 mph or stronger and hail of one inch or more in diameter. The probability of either occurring within 25 miles of any point in the slight risk area is five percent.

The normal wind probability for any May 12 is about two percent, according to climatology data from the National Severe Storms Laboratory. Today’s probability, therefore, is roughly twice the normal probability for this date.

The normal hail probability for any May 12 is about one percent, so today’s probability is roughly five times normal.

There’s no reason to be alarmed by a marginal risk, but if you live in that half of Indiana, it’s wise to remain weather-aware today, especially if you’ll be involved in any outdoor activities (e.g. baseball games, etc.). Remember that all thunderstorms, severe or not, bring lightning, which kills people who are outdoors.

The SPC plans to update its outlook for today by 12:30 p.m. EDT.

Slight risk of severe storms in Southern Indiana Tues. May 10

National Weather Service Storm Prediction Center Day 2 Convective Outlook Mapy for Indiana issued May 9, 2016 shows a slight risk of severe storms in extreme southern Indiana between 8 a.m. EDT May 10 and 8 a.m. EDT May 11, 2016Extreme southern Indiana (shaded in yellow on the map above) has a slight risk of severe storms tomorrow, according to the “Day 2 Convective Outlook” that the National Weather Service Storm Prediction Center issued early this morning. The slight risk area includes Vincennes, Jasper, Corydon and Evansville, among other communities.

A slight risk on a day-two outlook means a 15 percent probability of any one or more of the following types of severe weather occurring within 25 miles of any point between 8 a.m. EDT tomorrow and 8 a.m. EDT Wednesday:

  • Tornado
  • Damaging straight-line severe thunderstorm winds of 58 mph or stronger.
  • Large hail of one inch or more in diameter.

The normal probability of one or more of the above on May 10 is approximately three percent, according to climatology data from the National Severe Storms Laboratory. That means tomorrow’s probabilities in the slight risk area of Indiana are approximately three times what’s normal on May 10.

The SPC plans to update its outlook for tomorrow by 1:30 p.m. EDT.

ARRL HQ: No guidance on closed ARES nets

ARRL logoA staff member of the American Radio Relay League, the United States’ largest organization of amateur (ham) radio operators, says he is not aware of any “ARRL guidance to restrict participation in a net.”

Sean Kutzko, KX9X, media and public relations manager, responded April 23 to an inquiry this blog made of the League’s emergency preparedness manager April 12. I asked the questions below after learning of a newspaper article about a Texas Amateur Radio Emergency Service (ARES) net turning away a licensed amateur. ARES is a program of the ARRL.

  • Does the ARRL provide guidance to its ARES leaders regarding the restriction of participation in ARES nets (i.e. the operation of “closed” nets during which only certain amateurs are permitted to transmit)?
  • If so, what guidance does the ARRL provide on this matter?
  • Under what circumstances (if any) should a local ARES net be closed to all outsiders?
  • What legal authority (if any) does an ARES net control station have to bar any licensed amateur from checking in and/or participating?
  • By barring certain amateurs from participating, does an ARES net risk interfering with a licensed amateur’s ability to transmit an emergency message in violation of 97.101(c)?

Below is the verbatim response from the League’s PR guy:

“One of the cardinal rules of all facets of Amateur Radio is “listen, listen, listen.” If Amateurs can provide data of _legitimate_ value to a weather net that is responding to a weather situation, they should be able to do so.  That said, if an Amateur has nothing to contribute to such a net, the Amateur should remain silent to allow legitimate traffic to be passed.

“I’m not of aware of any ARRL guidance to restrict participation in a net. Amateurs should listen to the net control station for guidance on what information is needed, and remain silent if they cannot provide information that fulfills the requested need. Net control stations should listen to the request being made of participating stations, as bona fide emergency traffic takes priority and can come from anyone.”

Texas ARES official bans closed nets

North Texas ARRL section Twitter logoA high-level Texas official of the Amateur Radio Emergency Service (ARES) has created a policy that bars ARES groups under his purview from prohibiting the participation of any licensed amateur radio operator in their ARES nets.

As this blog explained in an earlier post, ARES is a program of the American Radio Relay League (ARRL), the national organization of ham radio operators. Regional, elected ARRL section managers appoint ARES leaders within their sections, including section emergency coordinators (SEC), who lead the program at a section level and district emergency coordinators (DEC), who lead it at a multi-county level.

Matthew Morris, K5ICR is SEC for the ARRL North Texas section, which is made up of dozens of counties, including Wichita County. As SEC, Morris has authority to create policy for all ARES organizations in his section.

When contacted by this blog via email, Morris wrote, “I’m not sure it was so much a revision of policy but just that we codified into policy what’s been a long-standing best practice for ARES.”

The newly codified policy includes two parts; a definitions section and the section below:

Section 1.02 Closed Nets Prohibited

(a) All ARES nets shall be open for participation by any licensed amateur. No net control station or ARES leadership acting in an official capacity shall prohibit the good faith participation of any licensed amateur.

(b) Nothing in this section shall be construed to prevent the establishment of minimum reporting criteria by a net control station or ARES leadership as appropriate to the situation at hand, so long as these criteria are not established intentionally or knowingly to prevent the participation of an amateur or group of amateurs.

Morris promulgated the policy after an article in a Texas newspaper described the Wichita County ARES net shooing off an amateur radio operator who attempted to check into the group’s severe weather net. On an audio recording of the net, one can hear net controller Jerry R. Stanford, KD5INN tell Australian storm chaser Daniel Shaw, VK2FSRV, “I do not want to hear you transmit on this frequency. We have a closed net.”

In a subsequent email to this blog, Charlie Byars, the DEC responsible for Wichita County (who the newspaper article quoted), confirmed that the Wichita County ARES did not permit outsiders to participate in its net, except to transmit emergency reports. It accomplished this by declaring the W5US repeater — on which the net operates — to be closed, with the blessing of the repeater’s owners. A closed repeater is one that only stations authorized by the repeater owner may use.

The North Texas section’s new policy prohibits the practice of conducting an ARES net on a closed repeater. The SEC has no authority, however, over storm spotter nets that are not affiliated with the ARES.

This blog sent email April 19 to the trustee of the Wichita Falls repeater that the Wichita County storm spotters use to ask, “Will the W5US repeater comply during future severe weather nets and end its policy of becoming a closed repeater during such nets?” If the trustee responds, I’ll update this article accordingly.

It is interesting to note that one day after Morris issued the section’s new ARES net policy, the Facebook page of the Wichita County ARES changed. The page title changed to “Wichita County SKYWARN” and the profile picture changed from the ARES logo to the SKYWARN logo. That same day, Justin Reed, NV8Q reported on a storm chaser Web forum that “As of today the Wichita County ARES group has renamed themselves to Wichita County Skywarn in order to get around the ‘open net’ requirement. So nothing has really changed here.”

Today, this blog reached out again to Byars via email, who replied, “As far as I know we are still ARES, and will stay that way.” Later the same day, the group’s Facebook page changed again. Its title became “Wichita County ARES / Skywarn” and its profile picture became the the ARES and SKYWARN logos side-by-side.

This blog congratulates Morris on his prompt action to implement best practices in section policy and encourages all ARRL sections to enact similar policies, if they do not already exist.

The editor of this blog leads a SKYWARN ham radio net in Indiana. A future post will discuss how that net operates and why all licensed radio amateurs are welcome and encouraged to participate fully in it.

Audio: Texas ARES NCS rejects Australian storm chaser

Yaesu FT-8900 dual-band amateur radio transceiver tuned to 146.94 MHz and 147.255 MHzIn an earlier blog post, I reported that the owners of a Texas ham radio repeater prohibit use of the system by licensed amateur radio operators who are not members of the local Amateur Radio Emergency Service (ARES) group when an ARES storm spotter net is in session.

My blog post was based on a newspaper article about the net shooing off a ham who wanted to check in.

Below is an audio clip of an exchange between Australian storm chaser Daniel Shaw, VK2FSRV and net control station operator Jerry R. Stanford, KD5INN. Listen and decide for yourself what you think of this exchange. I welcome your comments, especially regarding whether your local SKYWARN net prohibits check-ins by outsiders and why or why not.

Outsiders not welcome on Texas ham radio storm spotter net

Members only sign handing on door knobUpdate: Texas ARES official bans closed nets

Trained storm spotters in the National Weather Service (NWS) SKYWARN program who are also licensed amateur (ham) radio operators should not assume they’ll be welcome on SKYWARN nets while traveling.

A Wichita Falls, Texas newspaper article republished this week on the “Emergency Management” magazine website reports that a local official of the Amateur Radio Emergency Service (ARES) is concerned that hams who are not members of the Wichita County ARES – especially hams who are storm chasers – try to check into the group’s SKYWARN net. The “Times Record News” report called such hams “intruders” who net control stations must “shoo” from their “closed radio frequency.” Such hams “are told they are welcome to listen — but not to talk,” the newspaper reports.

Here’s an audio recording of the exchange that prompted the newspaper story:

ARES is a program of the American Radio Relay League (ARRL), the national organization of ham radio operators. Regional, elected ARRL section managers appoint ARES leaders within their sections, including district emergency coordinators, who lead the program at a multi-county level.

The newspaper article quotes ARES district emergency coordinator Charlie Byars, W5GPO. This blog contacted Byars via email for more information about the situation in northern Texas. He confirms that during severe weather events, the W5US repeater system on which the local SKYWARN net operates becomes closed.

A repeater is a system commonly used by ham radio operators that receives a signal and re-transmits it, usually with higher power and from a better location, to provide greater communication range. Such equipment is often owned by clubs and sometimes by individuals. While the radio frequencies that repeaters use belong to the public, federal regulation 47 CFR 97.205(e) explicitly permits the owner of any repeater to limit its use to certain stations.

Byars explains that the W5US repeater is normally open to all hams, but its owners invoke 47 CFR 97.205(e) and close it to unauthorized users during severe weather events. But, Byars adds, that doesn’t prevent any ham from reporting severe weather. “We will take an emergency report from anyone, and refer the information to the NWS office,” he explains.

Beyond the transmission of an emergency report, however, the owners of the W5US repeater prohibit any use of the repeater during SKYWARN operations by anyone who is not a member of the local ARES group.

This blog contacted ARRL staff via email to learn whether the national organization offers guidance to leaders of its ARES program regarding the use of closed nets. The League’s April 23 reply appears in a separate post.

Fortunately for people like the Australian radio amateur who attempted to check into the Texas ARES net, the NWS office in Norman, Okla. – which serves that part of Texas. – welcomes “spotters, chasers and anyone else” to “submit storm reports at any time,” writes Rick Smith, KI5GT, the office’s warning coordination meteorologist. In an email to this blog, Smith suggests the following alternatives to ham radio, in order of office preference: Telephone, SpotterNetwork.org, a form on the office’s website and Twitter.

Find more details about various ways to participate in the SKYWARN program while traveling, in my March 6 post to this blog.

Is your local SKYWARN net closed to outsiders? Do you have any opinions on the practice? Leave a comment to let us know.

The truth about wireless emergency alerts

All national commercial mobile service providers (CMSPs) in the U.S. do their best to approximate National Weather Service warning polygons when relaying tornado warnings through the wireless emergency alert (WEA) system, according to an executive of CTIA, a wireless industry trade group. The result is geographic targeting that is more granular that the county-wide targeting of NOAA Weather Radio. And the industry is considering proposals to further improve the geographic targeting of WEA.

Information that CTIA assistant vice president for regulatory affairs Brian Josef provided to “W9LW’s Ramblings” contradicts a graphic that appeared on Twitter April 6 (below).

The graphic in the tweet originally appeared in a 2013 blog by WeatherCall, a company whose sales pitch includes pointing out shortcomings of WEA and other warning modalities. The tweet and blog post claim that wireless emergency alerts get sent by every CMSP tower in every county covered by a warning polygon, thus providing irrelevant warnings to more people than would receive the warning via NOAA Weather Radio.

Brian Josef, Assistant Vice President for Regulatory Affairs, CTIA
Josef

This might have been true when WEA was first implemented in 2012, the CTIA’s Josef told this blog. And to this day, federal regulations for WEA continue to permit the practice of alerting entire counties. But shortly after WEA was implemented, carriers found ways to improve the granularity of alerts. Today, every national carrier geographically targets tornado warnings based on NWS polygons, Josef said.

The system remains less than perfect, however. The most common way carriers target the reception of WEA messages is by broadcasting them only from the towers that are physically located within the warning polygon, according to a 2015 report by the Johns Hopkins University Applied Physics Laboratory.

In the graphic example below, black hexagons represent the coverage areas of one carrier’s cell towers (in reality, coverage areas are not hexagonal) and the black dots in the center of each hexagon represent the towers themselves (in reality, towers are not usually spaced so evenly). The red polygon represents the boundary of an example tornado warning. Green hexagons represent the areas that would receive that warning via WEA, if the carrier sends it only via towers that are located within the polygon.

Selecting cell towers (black dots) within a tornado warning polygon (red) is the most common way mobile carrier geographically target wireless emergency alerts, according to a Johns Hopkins University study.
Selecting cell towers (black dots) within a tornado warning polygon (red) is the most common way mobile carriers geographically target wireless emergency alerts, according to a Johns Hopkins University study. W9LW graphic.

As you can see in the graphic above, people in the white areas inside the red polygon will not receive the warning, even though the warning includes their locations. People in green areas outside the red polygon will receive the warning, even though the warning does not include their locations.

“There’s always going to be some overshoot, there’s going to be some undershoot, but they’re trying to employ the techniques that best approximate that alert area,” Josef said of the mobile phone carriers.

Researchers at Johns Hopkins University suggest a new, more precise geo-targeting method for wireless emergency alerts in a report published last June that the U.S. Department of Homeland Security commissioned. It proposes arbitrary-size, location-aware targeting (ASLAT), through which carriers would broadcast an alert over an area larger than the warning polygon and individual mobile devices would determine whether to display the warning, based on each device’s own calculation of its location.

ASLAT would require some changes to existing WEA standards, cellular network functionality and mobile device behavior. Josef stressed the importance of assuring that any new targeting technique not increase data congestion on cell sites at a time when weather conditions would already increase device usage.

“The carriers are constantly looking at ways to further refine and enhance geo-targeting techniques,” Josef said. “We also want to make sure we don’t endanger what has been a successful service.”

Illinois man video-records tornado hitting his house, survives against all odds

Against all odds, Clem Schultz somehow survived a direct tornado strike on his Fairdale, Illinois home, while video-recording the storm. His video (above), while dramatic, provides a poor example. He needlessly decreased his chances of survival.

A story in the Arlington Heights, Illinois “Daily Herald” hints that Mr. Schultz was aware of a tornado warning and indicates that he did not believe the tornado would strike his village. It indicates that “there was no time for the 85-year-old to hurry back downstairs to the kitchen” where his wife was.

From the the first video frame in which we see the tornado, however, until the frame in which the utility pole begins to fall, nearly two minutes elapse. That should have been plenty of time for everyone in the house to seek shelter. The National Weather Service’s tornado warning provided the Schultzes even more time. It was issued 14 minutes before the tornado hit the village.

“There was no point in getting in the cellar,” the “Daily Herald” story continues, “which was basically a hole barely big enough to hold their furnace.”

Unfortunately, Mrs. Schultz did not survive, becoming one of the storm’s two deaths.

We’ll never know whether the outcome would have been different had Schultz and his wife gone to the safest place that their house afforded as soon as the NWS first issued the tornado warning. If there was no room for them in the furnace cellar, that might have meant going to the most interior room on the first floor, as experts routinely advise.

Sometimes people die, even when they follow expert tornado survival advice. But the sensible thing to do is to put the odds in your favor. When a tornado warning includes your home, take shelter as best you can.

Don’t gamble with your life by following follow Schultz’ example. Give yourself the best possible chance of survival.