Monday, September 26, 2011

Joplin, Revisited

The NWS put out their final assessment of the infamous EF-5 Joplin tornado that occurred on May 22.

The report didn't touch much on the final death toll. 159 people lost their lives in the tragedy, the most from a single tornado since 1953. The report also didn't cover the damages caused.

What the report did cover, in great detail, was the processes that lead up to the warnings being issued ahead of the tornado and the response the citizens took to protect themselves. The findings of the report are somewhat surprising!

The NWS Assessment team took an ethnographic approach to conducting some of it's research. The report stated that ethnographic techniques were used to, "Understand residents points of view regarding the process of warning receptions to warning responses and how decisions were made."

I am big fan of this approach. It definitely helps to know your target audience, in any situation! Understanding the thought process of the citizens is a huge first step to improving warning timing and distribution. Over 100 people were interviewed for the report. One of the more important findings was how the people in the path of the twister processed the warning information.

In this day and age, social networking is huge. Facebook, Twitter and text messaging are huge communication tools. These are great ways to get information out. Meteorologist James Spann, who covers the Birmingham, Alabama market, has utilized these tools about as well as anyone can. He sends out tweets and posts that pertain to weather watches and warnings in any part of his television viewing market. There is great potential in social networking when it comes to severe weather. The problem with it is two-fold. First, not everyone uses social media. Those who don't would then have to find their warning information elsewhere. The second problem to this is validity. Not everyone who is posting about a tornado or thunderstorms are trained experts. So there could be a lot of false information flying around out there.

Social media can be one method of risk awareness. What are others? Many towns in Tornado and Dixie alley have tornado sirens. Weather radios are common as well in these parts. T.V. weather reports are the best way to get access to severe weather information. In Joplin, it is "community policy to sound sirens when a tornado is moving towards Joplin OR a severe thunderstorm with expected winds to exceed 75 m.p.h." This causes a big problem.

When the sirens go off, what are they warning for?!?! There is a large difference between a severe thunderstorm with damaging winds and a tornado. While both can be destructive, a tornado is far more deadly than strong winds. There needs to be clarification between the two events. The people in Joplin on May 22nd had to process two different blasts of the siren. This should have been all it took for people to act. However, the report found out that people acted, "after processing a variable number of risk signals...". In a deadly, EF-5 tornado situation, people can not afford to take time and contemplate a "variable number" of warnings. There were many reports that people did not act until they visibly saw the tornado! Why weren't the sirens enough?

Several people who were interviewed said that tornado sirens have lost their credibility. A few of the responses show why:
 "the sirens have gone off so many times before"
"bombarded with sirens so often that we don't pay attention"
"...[the sirens] go off for dark clouds"

These responses go to show that people who live in tornado-prone areas are probably desensitized to the sirens. Folks would point to data to prove why they treat the sirens with such complacency. In all tornado warnings issued by the NWS nationally, it was found that over 75% of the warnings were false alarms. That information was averaged over roughly the last 4 years. So it is easy to see why people assume that a tornado siren is just someone crying wolf! But here is the bottom line, every environment is different. On this particular day, the environment was primed and ready to fire off dangerous, long-track storms. So you just don't mess with weather, even if it means you have to take to safety for 20 minuets or so.

What needs to be done to prevent this confusion and complacency again? It is critical that the NWS, media members and community officials are on the same page when it comes to warnings and stressing immediate action. Sirens need to be blasted for one type of event only. A reverse-911 action plan may help as well. Anything that puts emphasis on the danger of the situation and allows enough time for action to be taken.

This problem of complacency runs far past tornadoes and Joplin, Missouri. When faced with an approaching hurricane, several people disregard warnings and evacuation requests to ride out the storm because they think that the weather man is wrong, or that it would never happen to them. It is downright foolish to challenge mother nature. The minuet you don't respect it, it can take your life. 

Here is the link to the full NWS Joplin Tornado Assessment

Wednesday, September 14, 2011

La Nina Returns?

NOAA has put out a La Nina Advisory for the 2011 winter season. That's right folks, La Nina appears to have re-developed and is here to stay a bit longer than first thought.

What exactly does La Nina mean, you may be asking? It essentially is a cooling of Sea Surface Temperatures (SST) in the central and eastern portions of the tropical Pacific Ocean. The set up has warmer than average SST's over the western Pacific and cooler than average SST's in the central and eastern Pacific. La Nina typically occurs ever 3-5 years but consecutive episodes occur nearly 50% of the time, according to the NOAA Climate Prediction Center. While La Nina stems from the anomalies of SST's, its impacts go way beyond ocean temperatures.

Sea Surface Temperatures showing a cooler eastern Pacific which signals a La Nina return. Via NOAA CPC.
Winter of 2010 in the United States was a record-setting one. High snowfall totals lead to record Spring flooding and severe weather that was off the charts! The exceptional drought that is on-going in the South...yup, put that one on La Nina. Wichita Falls, TX became the first location with 100 days at or above 100 degrees this year! So the news that La Nina has reformed does not offer much in the way of relief.

What can we expect for winter 2011? Average La Nina winters cause wetter than normal conditions here in the Pacific Northwest and can often expect cooler than average temperatures, too. La Nina doesn't offer much drought relief during the winter months either for those in the South and Southwest,
“This means drought is likely to continue in the drought-stricken states of Texas, Oklahoma and New Mexico,” said Mike Halpert, deputy director of the Climate Prediction Center.  
Typical La Nina setup
Beyond the upcoming winter, it is tough to tell just how long and strong La Nina will be. Should it last into next Summer, it could mean another active hurricane season. During the 2010-11 La Nina conditions, forecasters predicted a very active tropics with 14-19 named tropical storms. As of today, we are sitting at 14 named storms this season. Pretty good, huh? With those cold waters in the Pacific, oceans try to balance out by warming up the tropical Atlantic waters to above average temperatures. So, if La Nina lingers around for another Summer, things could be active again.

With La Nina's anticipated return, records could fall again this winter. That would not be welcome news to most.

Tuesday, September 6, 2011

Tropical Patterns

Katia has reached major hurricane status in the Atlantic. After Irene lashed the Carolinas and skirted the Northeast, Katia has a lot of east-coasters holding their breath. As Katia formed, I had mentioned that the storm track appeared to take it out to sea and avoid being the second storm to hit the east coast in a month. So far, so good. Here are computer models for Katia's track.

All models have the storm re-curving out to sea. However, a common issue with tropical forecast is that a forecaster may wind up "riding" the models and forecasting what the computers spit out. When it comes to tropical forecasting, patterns almost work better than guidance.

Gut feelings often can be the best forecasting tool, assuming you have knowledge of the situation. Now, being from the Pacific Northwest, I obviously have little knowledge of topical histories. But having picked up a few hints along my studies have helped me to generate some opinions about the 2011 tropical season. My gut instinct was that Katia would curve out to sea. Here is why I stated that.

Take a look at Katia's actual track below.
Let's take a look at where Katia formed. Katia got tropical depression status at roughly 26 degrees West latitude and a day later was a tropical storm at roughly 33 degrees West latitude. So Katia formed rather quickly off the west coast of Africa. Through historical observations made, it has been determined that 90% of all tropical cyclones that develop EAST of 35 degrees West latitude will RE-CURVE off to sea. That is the exact situation we have with Katia. This was my first clue.

My second clue came through a process called teleconnectoins. Meteorologists use teleconnections in order to "anticipate" what may come down the road for a specific location but is used in the most general sense. The basics of this is this: what is occurring in the western Pacific (off coast of China/Japan) will occur on the U.S. east coast roughly 6-10 days later. Nothing is specific, it just assumes general trough/ridge patterns. Teleconnections can help forecast the track of a storm brewing in the Atlantic. When Katia formed, I took a look at what was occurring in the western Pacific. A trough was located just off the coast of Japan. So I inferred that this trough would generally move eastward and ultimately pull Katia out to sea when she wanders towards the U.S. coast!

I've been told it's better to go down on your own forecast than someone else's. So I decided to own my gut instinct and say what I thought; Katia will miss the U.S. and re-curve out to sea. I'm more than happy to live and die by my own forecast. That was a valuable advice given to me by one of my teachers whom I greatly respect.

Looking ahead, we have a new tropical disturbance developing in the east Pacific. Invest-95 has a high probability of becoming a tropical cyclone. Let's compare the track of Katia to that of Invest-95. 

Invest-95 has formed a little south of Katia's track, and is forecasted to track a bit north of Irene's path. Lots of time however for Invest-95 to change, so I'm not making a call on this yet.