Tag Archives: tornadoes

“It’s all about the updraft”

College of DuPage meteorology professor Dr. Paul Sirvatka presents at the DuPage County Severe Weather Seminar, March 11, 2017
College of DuPage meteorology professor Dr. Paul Sirvatka presents at the DuPage County Severe Weather Seminar, March 11, 2017

The title of this post is one of the main points of a presentation I heard at the DuPage County (Ill.) Severe Weather Seminar March 11. College of DuPage meteorology professor Paul Sirvatka reminded spotters that the key to spotting a tornado in a classic supercell is knowing where the updraft is. As Dr. Sirvatka put it, a tornado is a “big sucky thing” that forms under an updraft.

Unfortunately, updrafts are not always easy to find. Depending on your location, important storm features can be obscured, making spotting difficult. And the closer you get to a storm, the more difficult it becomes to identify the important features.

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Spann discusses 2011 tornado deaths at Nashville Severe Weather Awareness Day

Conference room at Nashville Severe Weather Awareness Day 2016Editor’s Note: The Nashville, Tenn. National Weather Service office and other organizations hosted an annual “Severe Weather Awareness Day” at Trevecca Nazarene University Feb. 27, 2016. What follows is a guest post from Ken Helms, AB9ZD, who attended the event.

I enjoyed the Severe Weather Awareness Day 2016 in Nashville yesterday.

Alabama broadcast meteorologist James Spann
Spann

The keynote speaker was James Spann, chief meteorologist for ABC in Birmingham. He discussed the 2011 super outbreak that killed 252 people in Alabama and he focused on what happened, why people died, and what needs to be done differently. Among the reasons he gave for the high number of deaths:

  1. Low income families didn’t get the warnings (can’t afford weather radios, smart phones, etc).
  2. Each local station had its own way of categorizing the severity of a storm causing confusion.
  3. Too many false alarms over the years so some people didn’t take the warning seriously (crying wolf).
  4. Warnings by the news media were given by county and not localized enough for people to know if they were really at risk or not.
  5. Many people didn’t have an effective place to shelter from a tornado (very few basements in southern houses).

Spann is a very passionate speaker on the subject.

There was also a panel discussion with five of the local TV stations’ meteorologists which was interesting.

Representatives from the NWS and the county EMA discussed area tornadoes including one that hit Gallatin (a city not far from Nashville) in 2006 that killed eight people.

Basic and advanced storm spotter training was included as well.

The event was held in a large room and was well attended. It was nearly standing-room-only for Spann’s presentation — there were no empty seats around me. Quite a few students were there. A group of meteorology majors from another Tennessee college sat in front of me. Attendance thinned out as the day went on.

ARRL booth at 2016 Nashville Severe Weather Awareness DayThey had an area set up for representatives from the local TV stations, colleges, and the NWS outside the conference room. Most were handing out brochures along with things like pens, pencils, ice scrapers, and stickers. The American Radio Relay League (ARRL) had a table as well.

A must read for any journalist who ever covers weather aftermath

Weather blogger Dennis Mersereau is absolutely correct when, in a recent blog post, he admonishes journalists to choose their words carefully, especially when writing about weather disasters.

The impetus of his post was a People Magazine headline and tweet Dec. 24 that described the Dec. 23 tornadoes in the South and Midwest as “unexpected.”

People magazine’s original tweet about Dec. 23 tornadoes

I first learned about the above tweet (based on a headline which People later changed, after being blasted on social media) when my friend and National Weather Service meteorologist Nick Greenawalt tweeted about it:

You can see my comment at the time, above.

My lovely wife later helped me realize that there was a chance the writer of that headline did not intend to imply that the tornadoes were not forecast or that people in their path were not warned. Instead, she asserted, it’s possible that “unexpected” was simply an extremely poor word choice to communicate how unusual tornadoes are at this time of year.

In his recent blog post, Mersereau lays out the entire series of outlooks, watches and warnings that should have made every citizen in the affected area that tornadoes were likely that day.

He also makes compelling arguments for the idea that words matter in stories about weather aftermath.

Even if my lovely wife is right, at best, a member of People’s staff chose poorly when he or she wrote the Dec. 24 headline. But Mersereau is also right. Words matter. Especially when they appear in publications that have audiences the size of People’s.

We should all hold journalists to high standards in their choices of words.

I strongly recommend you read Mersereau’s post and share it:

http://www.dennismersereau.com/2015/12/when-storms-threaten-lives-words-matter.html

91 attend Fort Wayne SKYWARN storm spotter training

For the first time in a couple years, meteorologists from the northern Indiana office of the National Weather Service (NWS) personally conducted training of SKYWARN storm spotters in Fort Wayne Feb. 17. Warning coordination meteorologist Michael Lewis, KG4KJQ and meteorologist Michael “Skip” Skipper presented the training to an official total of 91 attendees. Approximately half of audience members raised their hands when Lewis asked hams to identify themselves.

Audience at NWS SKYWARN storm spotter training, Fort Wayne, Indiana, Feb. 2015
Figure 1: Ninety-one people attended NWS SKYWARN training in Fort Wayne Feb. 17 (Photo by Whitley County emergency manager Charlie Heflin).

The session included the usual information on the role of the spotter, storm development, local severe weather climatology, recognition of various weather phenomena, spotter safety and reporting procedures. A detailed description of the training is beyond the scope of this article, which will instead touch on a few of the highlights, especially those portions that were new this year. If you missed the training, NWS plans two sessions near Fort Wayne this month:

  • March 16, 6 p.m. ET, Paulding, Ohio
  • March 19, 6 p.m. ET, Bluffton, Ind.

Detailed information about both sessions can be found at on the NWS Northern Indiana website.

One new feature of the training this year was audience participation via electronic polling. The presenters evaluated audience knowledge before and after the training by asking them to respond to questions via text message, Twitter or Web page form. Responses appeared on the projection screen in real time.

Thunderstorm spectrum discussed

One highlight of this year’s presentation was a discussion of the thunderstorm spectrum (see figure 2). It ranges from single-cell “pulse” storms, to two forms of multi-cell storms, to the classic supercell thunderstorm. Large, strong tornadoes originate from supercell storms, but such storms are rare in the 37-county warning area (CWA) of the northern Indiana NWS office. Multi-cell storms, especially “derecho”-type squall lines can produce winds as strong as weak tornadoes, which is why spotters and the general public should not ignore severe thunderstorm warnings. It’s important for spotters to understand that, especially in the northern Indiana CWA, storms can change type one or more times during their existence.

Thunderstorm spectrum slide from NWS SKYWARN storm spotter training. Single-cell pulse thunderstorm, multicell cluster storms and squall lines, and supercell
Figure 2: Slide from NWS spotter training presentation, used with permission.

When it comes to tornadoes, 82 percent of twisters in the northern Indiana CWA create damage at the EF0 or EF1 levels of the enhanced Fujita scale (see figure 3). Note that EF0 tornadoes can have winds as week as 65 mph. Severe thunderstorms can and often do produce much stronger winds. Also note that EF0 and EF1 tornadoes are very difficult for NWS Doppler radar to detect, sometimes developing and dissipating between radar scans. Less than one percent of storms in the northern Indiana office’s CWA reach the EF4 damage level, with wind speeds of 166 mph or greater.

Enhanced Fujita scale with probabilities in northern Indiana county warning area
Figure 3: Slide from NWS spotter training presentation, used with permission.

Convective outlooks change

Situational awareness is an important part of spotter preparation and safety. The NWS Storm Prediction Center’s (SPC) convective outlooks are important situational awareness resources. Those outlooks look different now (see Figure 4). The new day one through day three convective outlooks have three risk categories between “general (non-severe) thunderstorms” and “moderate risk,” instead of the former single “slight risk” category. A “marginal risk” category now falls between “general thunderstorms” and “slight risk” and new “enhanced risk” category falls between “slight risk” and “moderate risk.” An SPC video briefing that fully explains the change in convective outlooks is available on the SPC’s website.

Categorical convective outlooks have new categories between "general thunderstorms" and "moderate risk"
Figure 4: Slide from NWS spotter training presentation, used with permission.

Also related to situational awareness is the announcement that the NWS office’s home page layout – and possibly navigation and URLs – will soon change. If you have bookmarked, for example, the severe weather briefing page on the northern Indiana office’s website, you might need to update your bookmarks after the change.

New spotter mnemonic: T.E.L.

This year’s training presentation uses a new mnemonic acronym to help spotters remember what the NWS needs to know (see Figure 5): “T.E.L. us.”

The “T” stands for “time.” Spotter reports should contain the clock time at which the spotter observed the event, even if it’s happening while the spotter sends the report. For example, rather than saying “now,” or “two minutes ago,” spotters should say “4:38 p.m.” or “1638 Eastern time.”

The “E” stands for “event.” This is the part of the report that contains detailed information about what the spotter saw, for example, hail (by size), a wall cloud, funnel cloud, tornado, wind or lightning damage (described), flooding, etc.

The “L” stands for “location.” This part of the report should contain a specific location, for example, “Allen County, Indiana, two miles northwest of Grabil,” or “In Fort Wayne, near the intersection of Coliseum Boulevard and Vance Avenue.”

Note that the reporting criteria are different than NWS warning criteria. For example, the NWS issues a severe thunderstorm warning for any storm that it expects to produce either winds of 58 mph or greater or hail of one inch or more in diameter. But the spotter reporting criteria are winds of 50 mph and hail of any size.

SKYWARN storm spotter reporting criteria from NWS Northern Indiana training presentation
Figure 5: Slide from NWS spotter training presentation, used with permission.

Finally, the NWS included in this year’s presentation a new reporting method matrix (see Figure 6). As in previous years, the meteorologists strongly recommended the use of the Twitter social media channel, while taking care to avoid discounting the importance of ham radio.

A primary advantage of reporting via ham radio is that others listening to the same frequency will simultaneously hear the report, aiding in the situational awareness of those who are monitoring. Another advantage is the resiliency of ham radio and the fact that it continues to work during Internet and cellular telephone failures. Disadvantages of reporting via ham radio include:

  • Inadequate volunteer staffing of the ham station at the NWS office often means that net control stations must re-file the reports by other means (e.g. telephone or an internal NWS Internet chat system).
  • When the ham station at the NWS office is staffed, the operator there must write down each report and then hand it off to a meteorologist, creating a certain amount of delay.
  • Until and unless the NWS issues a “local storm report” based on the spotter’s report, the information in the report is available only to those who are monitoring the frequency, which often includes few of the many spotters who are not hams and have no equipment with which to monitor.
  • Ham radio systems currently in use for SKYWARN provide no means of including photographic data with spotter reports.

Advantages of the Twitter social media channel include:

  • The channel does not rely on the limited availability of volunteer operators at the NWS.
  • Reports show up immediately on a computer in the NWS office, without relay or transcription.
  • Reports are visible immediately to anyone who has access to the Internet, including other spotters, emergency managers, members of the news media and the general public. As Lewis put it at one training session this year, “Call me and you and I know. Tweet me and the whole world knows.”
  • Reports can include photographs or video of events being reported, aiding in the NWS’ ability to validate the reports
  • The capacity of Internet channels is virtually unlimited, enabling the NWS to encourage sub-criteria reports.

Note that on the reporting methods matrix, the NWS encourages spotters to report winds of less than the normal reporting criteria of 50 mph (the approximate speed at which structural damage begins to occur) when using social media or the “mPing” app (more on that below). But for ham radio and telephone reports, the minimum wind is 50 mph. This is a sign that NWS really wants much more information from the field than it has received in the past but understands the limited capacities of channels such as ham radio and telephone.

For spotters who choose to use their Internet-connected mobile devices to file reports, a relatively new option is the Meteorological Phenomena Identification Near the Ground (mPing) app from the National Severe Storms Laboratory. The app is available for both the Andoid and iOS platforms and originally only accepted precipitation reports. The current version also allows users to send hail, wind damage, tornado, flood and other reports. Reports sent via mPing show up directly on Advanced Weather Interactive Processing System (AWIPS) terminals in NWS offices. A disadvantage of mPing is that all reports are anonymous and as such, users cannot identify reports as coming from trained spotters.

SKYWARN storm spotter guide to preferred reporting methods from NWS Northern Indiana trainnig
Figure 6: Slide from NWS spotter training presentation, used with permission.

In conclusion, I encourage all hams who are spotters to become familiar with Twitter, especially those who have Internet-connected mobile devices (e.g. smart phones). At the same time, I also encourage all hams to continue to make reports via ham radio, even if they’re also reporting via Twitter. This will assist in the situational awareness of spotters who are on the ham frequency as well as those who are only able to monitor Twitter.

I have become active on Twitter (@RadioW9LW, if you’d like to “follow” me) and will be happy to provide any assistance I can to any spotters who want to know more about Twitter. You can reach me via the “Contact W9LW” form in the right-hand column of this blog.