Alerting

Linkin Park and Weather Safety

WDT and NWS partner to make Linkin Park “Storm Ready”

Linkin Park’s touring manager, Jim Digby, is passionate about the safety of outdoor concerts and weather is one of the biggest hazards.  He likes to say “nobody’s kid should go to a concert and not come home.”

Mr. Digby is one of the co-founders of the Event Safety Alliance, a new organization made up of entertainment industry veterans, of which WDT serves as a sponsor. ESA was formed in the wake of several recent large venue incidents that have resulted in injury and even death of event attendees.

Over the past month, WDT has worked diligently with Jim Digby and Rick Smith, Warning Coordination Meteorologist of the Norman NWS forecast office, to meet the necessary requirements for the 2012 Linkin Park Tour recognized as a “StormReady Supporter”.

This recognition was given to Linkin Park because they have taken a very proactive stance with regards to weather safety. WDT has customized a weather decision support service called WeatherOps where-as our expert meteorologists provide forecasts and advisories to Linkin Park with a primary goal of allowing 2-hours lead time for any weather event that will result in evacuation of an outdoor venue.  Additionally, WDT provides all NWS watches and warnings to Linkin Park.

Linkin Park has established a weather “decision matrix” which they use to make decisions in real-time during hazardous weather so they do not need make critical decisions on the fly. When their point person receives an advisory or warning they have already decided what actions will be taken for a given event.

On Monday, August 28th, Rick Smith presented to the band members and Jim Digby the Storm Ready certificate.  I had the pleasure of talking to the group at this event for a few minutes and the band members were genuinely interested in weather safety and appreciative of the NWS and WDT for providing information that keeps their fans and crew safe.

Linkin Park is the first touring band to take a proactive weather safety stance.  The Event Safety Alliance, WDT and the NWS are all working hard together to make outdoor concerts safer, hopefully Linkin Park will be the first and set an example that other big and small artists along with outdoor venue managers will follow.  This is a perfect example of a public, private partnership that is providing great value to outdoor concertgoers!

Categories: Alerting, Severe Weather | Leave a comment

Storm-Based Tornado Warnings Reduce False Alarms and Hopefully Will Eventually Lead to Better Public Response

After experiencing a tornado in my hometown of Norman, Oklahoma, and hearing all of the stories of many people’s experiences during the event, I am very worried about the public’s general apathy toward tornado warnings and the resulting lack of taking any action.

What worries me? Many things, but my basic premise is that people do not respond because they perceive that most NWS tornado warnings are false alarms, i.e.,” I have lived through many tornado warnings without taking any action so why should I worry this time?”

I believe this lackadaisical response to tornado warnings is mainly caused by the perceived very high false alarm rate for tornado warnings, and there is something we can do about it now! The National Weather Service does a credible job of warning for tornadoes. Average lead-time between the issuance of a tornado warning has gone from zero minutes to 14 minutes in the past two decades mainly due to the use of the NEXRAD Doppler radar network and its capability to observe circulations in storms. But the false alarm ratio is still ~75%, meaning that 3 out of 4 tornado warnings do not subsequently have a tornado in them.

A second reason for the perceived high false alarm rate is the way that media relay information about storm warnings and how local emergency management activate sirens when tornado warnings occur.

The National Weather Service has been issuing their warnings (tornado, severe thunderstorm and flash flood) as “storm-based” warnings for many years now. That means that they do not issue warnings based on political boundaries (like cities or counties). Rather, the warnings are issued as polygons which precisely outline the area that the expert meteorological believes is in the hazardous path. Yet, many communities continue to set off their sirens for the entire city or county.

Also, warning graphics shown by local television meteorologists often show whole counties rather than the actual polygon warnings. And warnings provided by many “weather alerting” services alert for whole counties too.

So, can you imagine if 75% of tornado warnings are false alarms and if you also hear sirens, see graphics or get alerts every time a warning is anywhere in your county, (I get about 3 warnings from a county-warning based service for every warning that actually covers my location) then the total “perceived” false alarm ratio is nearly 90%. This is even a fundamental issue with traditional weather radios, which offer only county-based granularity even when equipped with the S.A.M.E. decoding technology.

We have a weather alerting app, called iMap Weather Radio, that alerts only if your location is within a NWS storm-based polygon. We have over 250,000 users of this app, and we have many testimonials about how we have saved people’s lives during tornados. However, our biggest complaint is: “I did not get an alert for the tornado/severe thunderstorm warning in my area even though the sirens were going off and the television meteorologist was showing I was in the warning.” We actually had to build a tool so that we could investigate each of these complaints……and guess what? EVERY single complaint we have received we have shown that the location of the person was actually NOT in the warning polygon even though they were getting alerts from multiple credible sources!

Two steps can be taken now to help address this issue. First, the technology exists to control siren networks in a way that only those within a warning polygon are activated. There should be an emphasis by federal, state, and municipal authorities to implement the use of such technologies. Second, media outlets needs to cease using county-based displays of warnings. These issues greatly accentuate the perceived false alarm rates that ultimately lead to lackadaisical response from the public!

Categories: Alerting, Severe Weather, Tornado | 3 Comments

Do Early Tornado Events Portend for an Active Tornado Season this Spring?

After 2011’s tragic number of tornado-related deaths, and the large number of destructive tornadoes that hit densely populated areas, many people ask me if 2012 is going to be as big of a tornado year as last year. Now that we already have had deadly tornado events in February, plus the historical tornado outbreak on March 1st and 2nd in the Southeast, the interest in this year’s storm season is even more intense. The March event was historical because over 110 tornadoes were reported during the 2-day period, surpassing the largest number of tornadoes reported in any tornado outbreak in the month of March. Sadly, there were at least 40 fatalities from this outbreak.

US Tornado Deaths

provided by Harold Brooks of the National Severe Storms Laboratory

As you can see in the Figure (provided by Harold Brooks of the National Severe Storms Laboratory), the 552 deaths in 2011 were anomalously large compared to the number of deaths over the past 25 years, and so were the number of tornadoes (1,690 as reported by SPC). For comparison, in the past 10 years, we averaged 1,274 tornadoes per year in the US and an annual average of 56 deaths. In general, the National Weather Service did a great job in providing watches and warnings for the large events that caused a high proportion of deaths in 2011, with warnings often providing more than 20 minutes of advance notice. You can see from the figure below that there is a steady downward trend of tornado-related deaths in the United States over the past 50 years, which is attributable to the continuous improvements in technology and techniques made by the National Weather Service during that period. But last year was far from the norm or trend, hopefully we will not see another year like it for a long time.

Will 2012’s tornado season be as terrible as 2011? The short answer is that statistically speaking, it’s highly unlikely that the number of tornado deaths in 2012 will match or exceed the numbers in 2011. The reason for this is simply because in 2011 many EF-4 and EF-5 tornadoes struck high density urban centers, and simple odds make it unlikely this will happen again in 2012. This is not based on any physical reason other than statistical probability.

Regarding the number of tornadoes expected for this year, that is an interesting scientific question. I have talked to many people in the Norman weather community over the past couple of weeks and asked them what they thought the Spring Severe Storm season would be like. The consensus is that Spring 2012 will likely be an active severe weather year but no one believes it will be as active as 2011. I have heard this from research scientists, storm chasers and operational meteorologists. The reasons that each knowledgeable person gave me varied, but in general most people agreed that the large scale weather patterns are different now than they were in 2011 so we should expect different results.

Looking back at 2011, there were many meteorological reasons for the large number of tornadoes and strong destructive tornadoes; one of the key reasons was that a very strong jet stream set up which frequently pushed upper-level energy to the Southeast part of the U.S. contributing to the outbreaks. This is more common during La Niña events, which is a phenomenon where sea surface temperatures in the central and eastern Pacific around the equator are cooler than normal.

In early 2012 La Niña is still around, but climate forecasts for the next few months suggest that the current La Niña condition is fading fast and likely by the May time frame will be in a near neutral (normal) pattern. Another key ingredient to severe weather is warm moist air. And in the South and Southeast this winter there have been very few strong cold fronts that have penetrated all the way through the Gulf of Mexico; so Gulf sea surface temperatures are already near 70 degrees.

What does this mean for weather and storms east of the Rockies during the spring storm season? Based upon discussions with a large number of my “severe weather expert” friends, I would say there are two camps, one that believes that early events this spring in the SE will likely continue due to the large scale weather patterns and the warm moist air that is nearby, creating a good environment for storms; then as La Niña abates and upper level patterns shift, storms and tornadoes will be reduced and tend more towards climatology as we get to the May time frame, this would result in a slightly above average year for tornadoes with the biggest events in the Southeast in March and April.

The second camp is similar in that they believe that early in the year there will be the strong and frequent severe storms in the SE for the reasons stated above but this camp believes that as La Niña abates and upper patterns shift, that energy will be directed over the Central Plains causing more frequent and severe events in that region in May and June. In this scenario, we would expect a very active year in total with the number of tornadoes well above climatology.

I personally am in the second camp. I believe that the most likely scenario is for the most frequent and severe storms to be in the SE in the next two months and then we should see that energy and thus storms move west into the Central Plains culminating in a very active severe weather and tornado season.

March 1st starts the unofficial “tornado season” in the Central Plains. There will be big tornado events and sadly people will be killed. Everyone that lives east of the Rockies should own a weather radio for your home and have the iMap Weather Radio App on their iPhone (WDT launched version 2 on March 2nd, Android launches in late April). Both provide lifesaving alerts. iMap Weather Radio provides “follow-me” alerts plus an interactive map with your location and the warnings overlaid on top of radar data. Additionally, in areas where WDT has media partners you can watch their live streaming television feed within the app during severe storm events. WDT has spent three years developing iMap Weather Radio and has a fully redundant computing infrastructure to ensure that watches and warnings are delivered in a timely manner. We are very proud of the app and the alerting systems we have built, and our goal is to save lives.

Over the coming months I will post to this blog at least once a week and more often during severe weather events.

Categories: Alerting, Severe Weather, Tornado | Tags: , , , , , , , , , | Leave a comment

Hurricane Irene – The biggest impacts are not going to be winds.

As I write this on Friday afternoon, Hurricane Irene is a Category 2 Hurricane aimed directly at Cape Hatteras, North Carolina. After Irene pummels North Carolina, she will move up the Eastern Seaboard almost paralleling the coast. When Irene gets to the North East it will cause havoc in some of our biggest cities. By that time Irene will “only” be a Cat 1 Hurricane or Tropical Storm, but winds will still be very strong (60-90 mph). It is likely that the biggest impacts will be from storm surges and large waves in some of the most important waterways in the North East, including Chesapeake Bay, Delaware Bay, and the waterways in Atlantic City and New York City.

precip forecast

Precipitation Forecast

Additionally, 10 inches or more rain will fall in some areas on top of already wet ground. This will cause significant flash flooding. WDT has partnered with Metstat to produce a new product, the Forecast Potential Flood Index, just launched today in beta mode. By combining the forecast rainfall amounts with regional climatological values, we can actually characterize the amount of rain expected in terms of how “rare” it is to get such amounts. This makes it much easier to ascertain potential impacts such as flooding than using simple amounts, since what is deemed heavy rain in one part of the country may be typical in another. The attached graphics show the forecasted rainfall amounts from WDT’s advanced, high-resolution numerical weather

"ARI" How Often This Occurs

prediction model along with the Forecast Potential Flood Index derived from those values. The first graphic shows the rainfall expected for the 24 hour period ending Sunday morning, and the second shows the 24 hour period ending Monday morning. This forecast suggests that some portions of New York state will see rainfall amounts that typically only occur once every 500-1000 years!

There is also deep concern that in areas where there has been significant rainfall in the past few weeks plus the additional rainfall from Irene, that tree root systems will not hold up to strong winds, so a big issue will be toppling trees which will lead to widespread power outages.

WDT has recently signed an Agreement with the National Hurricane Center where we are working with them to distribute real-time video from experts at the NHC on an hourly basis during the period leading up to landfalling hurricanes. These experts are describing the latest thinking on Hurricane Irene and updating you every hour. We have these videos on 600+ websites. To find a local media site that is carrying these videos, please go to www.imaphurricane.info or go to http://www.imapweather.com

Categories: Alerting, Hurricane, Severe Weather | Leave a comment

Smartphone – Key to Weather Safety

Driving in a car in a place that you are not familiar with can be a harrowing experience at times, especially if there is severe weather in the area. If you do not know which county you are in or what the local towns are, it is very hard to decipher whether a severe weather or tornado warning you hear over the radio is for where you are at or where you are driving to.

iMapWeather Radio iPhone App

WDT's iMapWeather Radio App for iPhone, iPad and iPod Touch

This happened to me early last week when I was driving my family from Minneapolis-St. Paul (MSP) to Northern Minnesota. But with today’s smartphone technology and WDT’s iMapWeather Radio app, I was warned in plenty of time to take action and steer clear of a severe thunderstorm that produced damaging winds over a wide swath of the suburbs of MSP. It is not my intent to market our company’s SmartPhone app in this blog, but it is a good case study to show how iMapWeather Radio and the latest smartphone capabilities really are life savers.

Here is the scenario. We were driving in the NW MSP suburbs in light rain showers when both my iPhone and iPad beeped and talked to me and told me that my current location was in a severe thunderstorm warning. I opened the iMapWeather Radio app and listened to the alert, then looked at the interactive map to determine where I was in relation to the storm and the warning. This is all made possible by iPhone providing its GPS location to apps and WDT’s patent-pending iMap Weather Radio app that gets those GPS locations and compares them to all NWS weather watches and warnings. If your iPhone is within the polygon of a watch or warning, and you are registered within the app to receive those type of watches or warnings, then an alert is sent to your iPhone.

So what did I do? I chose to drive perpendicular to the storm and not stop for lunch like we had planned. We did get into the edge of the storm, but only were in heavy rain and maybe 30 mph winds for less than 5 minutes.

This scenario shows how communicating severe weather warnings to mobile devices is one key way to communicate to the public. If I had heard the warning on the radio, I would not know which county I was in or what the local town names were. I did not have access to any other communication media, thus, a mobile device was the only way I could have received this warning. Additionally, being able to view the warning and radar echoes on an interactive map gave me situational awareness that was key in making a decision on how to proceed to ensure that my family and I were safe.

Smartphones are great tools for many reasons, but when it comes to weather safety they are a key component in communicating warnings, especially to people that are not at home.

Categories: Alerting, Severe Weather | Leave a comment

The Hurricane Cone of Probability

Although I spent most of my career focusing on severe weather and its detection and nowcasting, I regularly observe how the National Hurricane Center (NHC) communicates threats from hurricanes, drawing corollaries with how severe thunderstorm and tornado threats are transmitted to the public. My impression is that the NHC has spent considerable time over the years working on how to represent hurricane locations to the public.

Cone of Probability for Hurricane Alex 2010

Cone of Probability for Alex (2010)

You may or may not know how the “hurricane cone of probability” produced by NHC is created. The cone represents the probable track of the center of the tropical cyclone and on average 67% (2/3) of the center locations will fall within that cone. They can calculate this cone because they assume that their forecast errors in the past 5 years will be the same as their existing forecasts.

I have always been impressed at how rigorous NHC’s approach is in calculating the probability cone. This is quite different than severe thunderstorm warnings or tornado warnings where local NWS meteorologists “on the fly” have to determine the size and location of the warning.

Of course there are issues in both approaches. If you think about the NHC cone of probability, if 2/3 of the forecasted center locations are within the cone, that means that 1/3 will be outside the cone. And I think that just as much of an issue is that the public interprets the area of the cone as the area where hurricane damage will occur, but that is not the case. NHC is representing where they believe 2/3 of the centers of hurricanes will fall, and hurricane force winds, surges, etc. definitely extend out from the center location by many miles.

On the severe thunderstorm and tornado warning side, the size and location of the polygon is placed in such a way that the meteorologist believes that the hazardous weather will always occur within the polygon. It would be interesting to see statistics on what percent of tornadoes for example occur outside tornado warnings, but my guess is that number will be very small. The biggest issue with tornado warnings is false alarms.

So all in all, communicating information to the public about hazards from hurricanes and severe thunderstorms and tornadoes is a difficult task. Meteorologists producing these warnings and forecasts have to deal with the reality that inherently all forecasts of meteorological events are by their nature not perfect. Thus, in the meteorological community we try to express the hazards to the public by making warnings or cones of probability larger in size and time than will ever actually occur to cover the uncertainty in our capability to forecast these events. Ultimately, progress in science and our capability to collect data on these events will help us reduce the uncertainty, leading to more precise and accurate warnings and forecasts.

Categories: Alerting, Hurricane | Tags: , , , | Leave a comment

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