The amateur radio SKYWARN net based in Fort Wayne will undergo slight changes, effective Feb 1, 2017. Formerly known as the IMO SKYWARN Quadrant Two Net, it will now be referred to as the Allen County SKYWARN Net. The net will continue, however, to accept and relay reports from spotters outside Allen County, including stations in places like DeKalb and Defiance County, which were not officially part of the former quadrant net’s responsibility. Continue reading
When the National Weather Service issued a tornado warning for northeastern Allen County, Indiana at 5:14 p.m. Aug. 24, 2016, more people in the county got their initial alerts from mobile phones than any other information source, according to an informal, online survey conducted by the publisher of this blog.
Of people who indicated they were anywhere in Allen County at the time of the warning, slightly more than 32 percent said they first learned of the warning via their mobile phones (including “Wireless Emergency Alerts,” alerts from apps, text messages, social media, etc.). Television was the second-most-frequently cited initial warning source, at nearly 21 percent. Outdoor warning sirens, commonly referred to as “tornado sirens,” came in third, at 17 percent. Just under eight percent of respondents credited NOAA Weather Radio as their initial warning source.
The warned storm created a tornado in northeastern Allen County at approximately 5:27, according to a report from the northern Indiana weather forecast office of the National Weather Service. That was about 13 minutes after the NWS issued the warning. The tornado stayed on the ground until approximately 5:39, cutting a five-and-a-quarter-mile path to the northeast and doing damage consistent with the EF-3 rating on the enhanced Fujita scale.
Nearly 62 percent of the survey’s 167 respondents indicated that they received the warning “immediately.” Another 19 percent said they received the warning with 10 minutes of its issuance, which would still have been a few minutes before the tornado touched down. Nearly 20 percent of respondents did not learn of the warning any sooner than 30 minutes after the NWS issued it, well after the tornado had lifted.
The NWS drew a five-sided polygon that enclosed 144 square miles to indicate the portion of northeastern Allen County to which the tornado warning applied. As a whole, Allen County encompasses approximately 660 square miles, so the warning polygon included less than a fourth of the county’s total area. The tornado’s entire path remained within the warning polygon, so people outside the polygon were not in danger.
Nearly half of all respondents indicated that they knew immediately whether they were within the warning polygon. Another quarter of respondents knew within five minutes whether they were in the warned part of the county. Nearly 18 percent, however, never knew with certainty before the storm passed whether they were in danger.
Best sources for location information
Among respondents who knew immediately whether they were within the warned area, nearly a third received their initial warning via their mobile phones, 24 percent via TV, 11 percent via NOAA Weather Radio and eight percent each via broadcast radio, amateur “ham” radio or outdoor warning sirens.
Among those who never knew with certainty before the storm passed whether they were in the danger area, there was a tie for the top response on how they first learned of the warning; 26 percent each reported TV and outdoor warning siren. A fifth received initial word of the warning from someone they know and 17 percent received it via their mobile phones.
Performance of outdoor warning sirens
Every operating outdoor warning siren in Allen County, including sirens miles southwest of the warning polygon, sounded shortly after the NWS issued the tornado warning.
Slightly more than 59 percent of respondents reported hearing an outdoor warning siren sometime during the hour of the warning, even if it wasn’t their initial warning source. Nearly 41 percent of respondents never heard an outdoor warning siren. The survey did not ask respondents whether they were outdoors at the time of the warning.
Respondents whose initial warning came from outdoor warning sirens were nearly evenly split with regard to their awareness of whether they were actually in the warned area. Slightly more than 24 percent reported knowing immediately, nearly 28 percent reported knowing within five minutes, nearly 21 percent said they knew within 10 minutes and nearly 28 percent indicated that they never knew with certainty before the storm passed whether they were in the warned area.
Of respondents who got their first notifications of the warning from outdoor warning sirens, more than three fourths were within the city limits of Fort Wayne at the time. Seven percent were in the city of New Haven and no more than four percent reported being in any other location within Allen County. The vast majority of the county’s outdoor warning sirens are located within Fort Wayne and New Haven. Approximately 71 percent of Allen County’s population resides in Fort Wayne and probably even more are employed in Fort Wayne.
People close to the warning
Only seven percent of respondents reported that at the time of the warning, they were in the city of Woodburn, the town of Leo-Cedarville or rural northeastern Allen County (in other words, in or near the warning polygon) at the time of the warning. Of those, the initial warning source was more evenly divided, with 25 percent each reporting mobile phone or television and nearly 17 percent each reporting NOAA Weather Radio, outdoor warning siren or amateur “ham” radio.
Only a third of these respondents reported ever hearing an outdoor warning siren, even if it wasn’t their initial warning source. Eight percent never knew with certainty before the storm passed whether they were in the warned area.
Readers should use caution drawing conclusions from these data, because the survey that generated them was informal, not scientific, and the number of respondents fell far short of the number required for a representative sample of people who were in Allen County at the time of the warning.
In terms of improving the tornado warning system, it would appear that steps to increase awareness of warned locations could be helpful. Outdoor warning sirens, of course, do not provide location information. For that reason, it’s surprising that some respondents who reported initially receiving the warning via outdoor warning sirens also reported knowing immediately whether they were in the warned area. Because Allen County activates all of its sirens for every warning, citizens cannot assume that their ability to hear a siren indicates that they are near the warning polygon, but it’s possible that some people do not realize this and that additional public education might be helpful.
Readers might be surprised that a number of respondents who initially received the warning via television were not immediately aware of whether they were in the warned area. If we assume the TV meteorologists who were on the air live at the time described the warned area, it is possible that those respondents initially learned of the warning not from live meteorologists, but from on-screen textual information.
Finally, it appears that a significant portion of people initially learned of the warning via their mobile phones. The time of day might have skewed those results, because many people were likely commuting at the time, and therefore away from TVs and weather radios. Also, commuters would have been more likely to hear outdoor warning sirens than would be people inside workplaces or homes. Still, it’s possible that the Wireless Emergency Alert system that’s enabled by default on all modern smartphones proved itself to be a valuable source of warning information.
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.
Extreme 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:
- 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.
The coming winter will likely be drier and warmer than normal in Indiana, according to the winter outlook that the National Weather Service Climate Prediction Center (CPC) issued yesterday.
This year’s El Niño (annual warming of Pacific Ocean surface temperatures along the coasts of Ecuador and northern Peru) is among the strongest on record. Forecasters expect it to influence weather and climate patterns this winter by impacting the position of the Pacific jet stream.
“A strong El Niño is in place and should exert a strong influence over our weather this winter,” CPC deputy director Mike Halpert said in a news release. “While temperature and precipitation impacts associated with El Niño are favored, El Niño is not the only player. Cold-air outbreaks and snow storms will likely occur at times this winter. However, the frequency, number and intensity of these events cannot be predicted on a seasonal timescale.”
The seasonal outlook does not project where and when snowstorms might hit or provide total seasonal snowfall accumulations. Snow forecasts are dependent upon the strengths and tracks of winter storms, which forecasters can generally not predict more than a week in advance.
— NWS Northern Indiana (@NWSIWX) April 11, 2015
Anyone interested in severe weather, history, or both will greatly appreciate a series of posts that the National Weather Service northern Indiana weather forecast office (WFO) published on the micro-blogging site Twitter yesterday.
And the WFO’s staff should be commended for excellent work gathering a great deal of historical information about the April 11, 1965 Palm Sunday tornado outbreak and for presenting it in such a compelling way.
The WFO prepared more than 100 tweets, many with images of actual text products issued via teletype the day of the outbreak. Other tweets contained Google maps with tornado tracks marked on them and photos of the tornadoes taken by citizens and photojournalists.
To add to the drama, the WFO scheduled each tweet to appear on Twitter at times coincident with the actual times of day that the events occurred. Genius.
The WFO’s series of tweets gives viewers a real sense of how different severe weather forecasting, detection and warnings were 50 years ago. For example, one thing that struck me was the Fort Wayne Weather Bureau office relaying to local broadcast media via teletype word of tornadoes in the Lafayette area. These days, because of better detection and communication technology, you rarely see WFOs issuing text products regarding tornadoes that distant.
— NWS Northern Indiana (@NWSIWX) April 12, 2015
If you missed the live tweets yesterday, you’re in luck, because they’re still visible on the Twitter website, even to people who do not have Twitter accounts. Just follow this link. When you get there, scroll down to a point near the bottom of the page to the tweet that reads, “We are beginning the live tweet of the events of 4/11/65, the Palm Sunday Tornado Outbreak,” and then read your way up from there.
I highly recommend it.