Monitoring Severe Weather Outbreaks Online

Fair warning; this is a VERY lengthy post. However, the information within this post is EXTREMELY important, especially for those who live in areas that are prone to severe weather. I do ask you to read through this post, as it breaks down the steps taken to monitor severe weather; using today’s (11/17/13) severe weather outbreak as an example. Additionally, some of the links may change following today’s event (they are “live” pages) – however, archived information can be pulled from the links by entering the date for Nov. 17, 2013.

First of all, in order for chasers and spotters to be activated by National Weather Service officials, there must be a considerable chance of severe weather. Many spotters and chasers analyze model imagery for elevated chances of severe weather. When the models begin to come into agreement, the potential of an event arises and usually, the Storm Prediction Center (SPC) issues a statement on the threat. These statements can be found on the SPC’s Convective Outlook, which are detailed for days 1 through 3, and threat areas mentioned for days 4 through 8. At the bottom of each image is a synopsis and analysis of the threat (although with the extensive meteorological jargon, it may be hard to understand for some). Today’s Convective Weather Outlook is a prime example of what the product looks like for an outbreak.

With today’s event, many NWS offices have activated their storm spotter networks. The individual NWS offices release statements, commonly in their Hazardous Weather Outlooks, that have a statement regarding spotter information. For an example, here is the Hazardous Weather Outlook for today’s event from the NWS office of Lincoln, IL. Additionally, the SPC will issue Public Severe Weather Outlooks (PWO) which is aimed at state and local emergency managers, along with spotters, chasers, and the general public. The information within a PWO is explained in terms that are easier to comprehend compared to the convective outlook discussions, and also provides a statement of precautions for the public to follow. I suggest to take the time to compare today’s PWO with the discussion of the convective outlook hyperlinked in the prior paragraph; can you tell the difference? Additionally, Severe Weather Specialist Dr. Greg Forbes of The Weather Chanel updates his Tor:Con for events such as these, with today’s highest Tor:Con value as a 9 for central and eastern Illinois and Indiana.

Now for the day of the potential severe weather outbreak, Mesoscale Discussions (MDs or MSDs) are issued by the SPC regarding the threat and potential for watch issuance. A national list of MSDs can be found on a branch of the SPC’s website. To view the MSD, simply click one of the red areas or one of the items on the list below. For an example of a MSD, here is MSD #2011 that was issued for much of IN, central/lower MI, and northwestern OH. Within the MSD discussion, the threat is listed and described (meteorological jargon, yet again), along with the probability of watch issuance and sometimes, even the specific type of watch (which for #2011, was 95% for a tornado watch).

Continuing on from Mesoscale discussions are the watches that are often issued shortly after the issuance of a MSD. Watches mean that conditions are favorable for the occurrence of a specific weather event. For this example, I want to focus on the tornado watches that have already been issued for today’s event. Additionally, I can take you a step further by introducing you to a rare form of a watch; a PDS. First, all active convective watches can be found on another branch of the SPC’s website. First example is of a regular tornado watch, TW #563; along with an evaluation of the threat, there are many other sections of information along with safety precautions within the watch page. I also suggest taking the time to flip through the different tabs at the top of the watch image to familiarize with the different information.

Now, for the introduction to the PDS watch. A PDS watch is issued when the threat is extremely high for significant severe weather and/or tornadic activity. PDS stands for Potentially Dangerous Situation, and although it can be issued as a severe thunderstorm watch (usually for a high probability of damaging winds or extremely large hail), it is most commonly seen as a tornado watch. For this example, I will use PDS TW #561 (which was the resulting watch issuance of MSD #2011, linked above). The information within the watch is similar to that of the normal tornado watch. However, there is a considerable difference regarding the risk evaluations.

Following the development of a thunderstorm, there is the potential for a warning to be issued. Warnings mean that the event is imminent or already occurring. Although you can find a list of warnings on a branch of SPC’s page, I prefer the self-updating warning page from the College of DuPage’s Meteorology department. Within the warning texts are reports, radar information, hazard information, location of threat, path of threat, and precautions for the public to follow. Something to always remember is to heed all warnings issued by your local NWS office!

The last topic I wish to touch is storm reports. Storm reports are very important when it comes to producing new warnings or analyzing an event. Even though most storm reports are relayed by emergency managers, state/county officials, and trained storm spotters and chasers, the public is also encouraged to make reports to their local NWS offices. The SPC keeps a current list of storm reports, which are separated into unfiltered and filtered categories. Often times, there is a statement within warning text on how to make a report to your local NWS office. First of all, here are the guidelines, events, and criterion for making a report. Additionally, if there is no information regarding how to make a report, different methods and instructions for making a report can be found here.


Analysis and Comparison of The Weather Channel’s Storm:Con and Tor:Con

With the chance of severe weather this weekend for the eastern Midwest, I figured a quick analysis of The Weather Channel’s Tornado Conditions Index would be fairly on-topic. TWC’s Tornado Conditions Index, commonly known as the Tor:Con, was developed by TWC’s severe weather expert, Dr. Greg Forbes. As stated on the Tor:Con’s webpage, the Tor:Con serves as an estimate of the risk for tornadic development within a certain radius. The Tor:Con’s scale runs from 0 to 10, which when multiplied by 10, gives the percent chance of the development of a tornado within 50 miles of a location. When the Tor:Con value is zero, the index is suggesting a minimal to nonexistent chance of tornadic development. However, the higher the Tor:Con value, the higher the risk is for tornadic activity.

Although the Tor:Con is a fairly downplayed analysis of computer models, it does a decent job of describing the risk to the general public. The Tor:Con is very easy to understand, while some of the model imagery can be extremely confusing to those who are not used to such technologies. For example, please compare the following links below – then decide which is easier for you to understand. The forecasts are current as of Nov 15, 2013 for the possible severe weather event forecasted for Sunday, Nov 17th. As with anything in the meteorological world, they are subject to change.
TWC’s Tor:Con
Significant Tornado Parameter (STP)
SPC’s Convective Outlook

With the success of the Tor:Con, The Weather Channel debuted the Storm:Con in the winter of 2012. Storm:Con was one of the three winter-related products that were released by TWC in 2012, along with the controversial winter storm names. The Storm:Con focuses on the impact of a winter storm on major cities, while the Tor:Con was more of a regional analysis. Storm:Con has the same 0-10 scaled index and is also based on computer-generated models. However, the final index value is “adjusted by evaluating subjective factors that influence societal impact.” This makes the Storm:Con more of a human-assumption than a science-based model, which has also introduced controversy in the meteorological world.

With the comparison of the Tor:Con and the Storm:Con, many give the gold medal to the Tor:Con. The Tor:Con does a decent job of matching the actual models and focuses on regional risk instead of localized impact. The Storm:Con is biased towards large cities and impact on travel rather than a complete focus on modeled  precipitation, wind, and temperature factors. Additionally, with the difficulty of forecasting winter systems, the accuracy levels of the Storm:Con and Tor:Con are considerably different. Regardless of what the science says, it is up to the viewer to discern such information to their personal use and decision-making. Just as one would do for news, the more information that is examined creates a better analysis of the threat.

On a personal note, I am asking of my followers and viewers to participate and share my survey regarding the use of social media to disperse vital news, weather, and emergency information. This survey is part of my research project for an honors contract at my college and I am hoping to collect at least 500 responses. The survey is a quick ten questions and should only take about two to three minutes. Thank you in advance!
Link to survey:

El Reno Downgrade: Proof of Faults within the Enhanced-Fujita Rating System?

I would like to begin this post with a note of spontaneity. I was originally going to discuss topics relevant to the eight-year anniversary of Hurricane Katrina. However, due to some breaking news over last weekend, I decided to switch gears and hold out for additional information to become available regarding the recent downgrade by the NWS of the El Reno, OK tornado of May 31st, 2013.

Let’s begin by discussing some technical information, summarized from the NWS regarding the outbreak about the setup of the severe weather outbreak for May 31st – June 1st in Oklahoma. Thanks to a stalled frontal system accompanied by a dry-line and an unstable air mass, conditions were favorable for tornadic activity.

The El Reno tornado was given a preliminary rating as an EF-3 following a NWS storm survey, which can be seen on the storm data page (press control-F and type in El Reno to find it among other storm reports). The reason for the upgrade to an EF-5 was the wind speed readings from a mobile doppler radar. Wind speeds measured by this radar system topped at 296mph, which is within the EF-5 rating category (second link, at the bottom of the page).

I think this situation comes to show that there are still many holes within the EF system. Yes, they improved the rating system through the conversion from the original F-scale to the EF-scale. However, with technology, should these ratings also incorporate data from radar readings? From the issuance of a typical severe thunderstorm or tornado warning, many are “radar-indicated”, so why is radar data being excluded when it comes down to the rating of a tornado? This snippet from The Weather Channel with Jim Cantore and Dr. Greg Forbes has a “short-n-sweet” explanation:

As Dr. Forbes said, the EF-scale is mainly a damage-based scale that focuses on the damage of structures. However, we also know that there are different building codes and minimal “permanent structures” as you move further away from lager cities. This brings to question whether a strong tornado over a rural area will receive a lesser rating due to less structural damage (because there were minimal amounts of structures to begin with). Using this same idea, you can also flip this the other way and have the possibility of a weaker tornado receiving a stronger rating because the area affected was more structurally dense. Some other things to consider would be the proximity to the actual tornado when there are structures that are damaged. Was it a direct hit, near miss, a few blocks away, or caused by a smaller “sister” tornado or multiple vortices? Did the tornado strengthen/weaken prior to causing damage? There are so many possibilities that need to be considered when dealing with a situation like this. We know technology is capable of determining wind speeds, with a small error margin, because that’s how severe products are issued, but when will we be able to find a balance between damage and data to precisely rate a tornado? Below is the link to the Tornado Warning issued for the El Reno tornado – 6:08pm CDT on Friday, May 31st, 2013, along with a list of other products issued that day.

Regardless of the changing of the EF-rating, May 31st, 2013 was a day of loss in the storm chasing community. Tim Samaras, his son Paul Samaras, and Carl Young, three well-known chasers from TWISTEX, and amateur storm chaser Richard Henderson lost their lives in the tornado. The El Reno tornado of May 2013 will go down in the record books as the widest known tornado in the US with a width of 2.6 miles and a path length of just over 16 miles.