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Posted at 10:00 AM ET, 06/ 8/2009

Scientists Get Closest Look Yet at Tornado

By Andrew Freedman

Riding along the VORTEX2 storm expedition

* A Stormy Week Ahead: Full Forecast | CWG Captures Tornado *

tornado-coming.jpg
Tornado begins to form in Goshen County, Wyoming on Friday, June 5. By CWG's Andrew Freedman.

"I think we're about to have ourselves a tornado," Glen Romine calmly stated - in the same tone of voice as one might order food at a restaurant -- as he gazed at a low and rotating mass of clouds, known as a wall cloud, in Goshen County, Wyoming on June 5. His calmness was in stark contrast to the broiling sky, as a funnel cloud descended towards the ground before lifting back up again just to the south of our vehicle along a narrow country road.

"Yup," I replied, my gaze locked onto a patch of bare ground right underneath the incipient tornado, awaiting touchdown. Suddenly, the lightly colored funnel touched the ground, and the world's most well-observed tornado was born.

Keep reading to continue on this storm-chasing journey...

This tornado, which occurred far from any heavily populated community, was surrounded by an armada of cutting edge scientific instruments - from mobile radar units to tornado "Pods" - which together are designed to scan a developing tornado from all angles and collect ultra high resolution data on its entire life cycle. These assets are being brought to bear as part of the VORTEX2 tornado experiment, a $10.5 million dollar project that is the largest tornado field experiment in history.

As the tornado spun its way to the east, I expected some jumping up and down and shouting like one sees in documentaries and reality shows like the Discovery Channel's "Storm Chasers." But Romine, a research scientist in meteorology at the University of Illinois at Urbana-Champaign, and graduate student Isaac Hankes were focused on their scientific mission, which left no time for indulging in tornado-related revelry despite the fact that the VORTEX2 team had waited since May 10 to see their first tornado.

Romine and Hankes were scouting locations to place two specialized instrument probes, called disdrometers, to take measurements of precipitation falling underneath the main updraft region of the supercell thunderstorm. The updraft region is the area where the thunderstorm breathes in air and launches it to great heights. 'Supercell' thunderstorms like the one in Goshen County have a persistent rotating updraft, and Romine said that scientists are becoming more aware of how precipitation processes and the related composition of the air mass underneath the updraft area can help determine whether a supercell produces a tornado.

Why some supercells are tornadic and others are not is one of the key mysteries that VORTEX2 researchers are trying to unlock.

disdrometer.jpg
The University of Illinois' Disdrometer probe, placed under a looming supercell thunderstorm in southern Wyoming on June 5, 2009.

Romine and Hankes pulled their modified Dodge Caravan into a small driveway. Ever so calmly despite the looming tornado, they got out of the van and lifted the disdrometer from the back seat. The data probe containing the disdrometer resembles a modern art sculpture that one might see at MOMA in New York, with a heavy metal base for an anchor, and several protrusions, including a black V shape near the top. To help ensure that it wouldn't blow over in high winds, the researchers placed the probe on level ground.

To measure precipitation characteristics such as how big the water droplets are and how fast they are falling, the disdrometers Romine and Hankes deployed utilize a small laser beam. Any precipitation that falls through the beam can be measured based on how it distorts the beam's voltage path.

Precipitation such as rain and hail offers clues, Romine said, about the air mass in the updraft region, since different droplet sizes have different surface areas. Small droplets may be more effective at cooling the air underneath an updraft, which could inhibit tornado formation.

Once their two probes were placed, Romine and Hankes began driving transects between them to gather data from the weather equipment mounted on top of the van. This data will be used to fill in the gaps regarding the weather conditions between the two probes.

wyoming-hailstone.jpg
Hailstone that fell in Goshen County, Wyoming on June 5. By CWG's Andrew Freedman.

As most other tornado chasers were hightailing it out of the area ahead of the storm's "rear flank downdraft," which is a blast of cool air, rain and hail that wraps around the backside of a tornado, the disdrometer team, with me in the back seat, headed in. Large hail began splattering on the windshield and bouncing off the pavement. Soon it was a deafening assault of golfball-sized hail and high winds, denting the car but sparing the windshield. Romine and Hankes hoped that their probes held up against the onslaught.

Upon retrieving the probes, Romine and Hankes discovered that a large and strategically placed hailstone had hit the power switch of probe one, knocking it out of commission after recording about six minutes of data. They shrugged it off as a lesson learned. "This is the joy of trying this stuff for the first time," Romine said, as he quickly modified the power switch to be more resistant to such hail damage in the future.

"Except for the switch, that was pretty much a perfect deployment for us," Romine said, summarizing the entire VORTEX2 team's experience for the day.

Romine, Hankes and others will work in the coming years to analyze the data they gathered in Goshen County and elsewhere, with the ultimate goal of translating their findings into improved tornado warning techniques that could save lives.

"Hopefully knowing more about what's going on internally with the microphysical structure of the storm will lead to better warnings," Romine said, noting that the next generation of radars that will replace the country's current network will have additional capabilities to detect precipitation characteristics in thunderstorms.

Follow Andrew Freedman (the author) on Twitter as he continues to ride along with the VORTEX2 team: http://www.twitter.com/capitalweather. Also, join CWG's Facebook group to see more photos from this expedition.

By Andrew Freedman  | June 8, 2009; 10:00 AM ET
Categories:  Freedman, Thunderstorms, VORTEX2  
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Comments

i saw something about this on the today show this morning - really neat pictures!

Posted by: madisondc | June 8, 2009 1:13 PM | Report abuse

In good part because we cannot predict tell which supercells are tornadic and others not explains why more than 70 percent of tornado warnings are false alarms. As stated in a news release
from today's meeting of the House Science and Technology Committee, "one of the largest barriers to getting the public to heed warnings is the complacency that grows out of numerous false alarms".

Consider, though, hitting it right 30% of the time ain't bad given the consequences of rejecting the "better safe than sorry" paradigm. Of course this applies well, for example,to hurricane warnings

Posted by: SteveT-CapitalWeatherGang | June 8, 2009 2:44 PM | Report abuse

It seems that the experts have been "dumbed down" during the past generation.

Numerous severe weather watches, warnings and statements are issued in today's world only to be complete false alarms.

Probably, less than 25% result in the forecast condition for the majority in the labeled area.

The public gradually adopts the "Boy who cried Wolf" attitude.

40 years ago, a severe statement usually resulted in observed confirmation of at least a threat.

Our tools of atmospheric interpretation are very sophisticated today compared to 1969, yet we are little children, when trying to understand the relevance of the data.

Posted by: AugustaJim | June 8, 2009 8:57 PM | Report abuse

Wow Andrew what an exciting week you must be having, chasing storms. The photos are maginficient and your ability to decribe what was happening around you left me yearning for an adventure. Who said science is boring?

Posted by: wiseowl30 | June 8, 2009 9:28 PM | Report abuse

AugustaJim, there is a balance that must be struck between detecting severe weather events and false alarms. If there were warnings for pretty much every weather event, we wouldn't miss many. If warnings were only issued when severe weather was reliably confirmed to be occurring, then many events would go unwarned as we don't have an adequate network of weather stations and spotters to observe the conditions everywhere. Further, forecasters must attempt to anticipate the development of these conditions before they actually begin to occur, with the aim of providing the public time to respond. Despite advances in technology, limited budgets results in most of our weather observing system being rather dated technology and with lots of 'blind spots'.

Predicting the atmosphere isn't like predicting the phases of the moon - the atmosphere has complex non-linear dynamics and physics that govern its behavior, which is progressively more challenging as the spatial scales shrink (predictability scales with the size of the atmospheric feature - so thunderstorms have predictability on the scale of minutes, whereas anticipating cooler than average temperatures across the Eastern US might have predictability out several days to perhaps a week). Further, warnings are for severe conditions to potentially develop anywhere within or near the defined warning region within the time window defined in the warning. Severe weather conditions are typically not expected to occur everywhere within the defined warning region. The skill to definitively know exactly what areas will experience severe weather conditions in the future and which ones won't fades quickly going forward in time from the moment conditions are identified (smaller than thunderstorm scale - so predictability of only a few minutes at best). Methods to try and improve predictability on these smaller time and spatial scales is an area of active research in the community, but there are definite limits.

Finally, I can assure you that issuing "false alarms" is something the weather service is trying to avoid. Many times, a severe weather event may have actually occurred, but simply was not observed. Does this make the warning unjustified? They are also heavily criticized for missing severe weather conditions (no active warning when an event occurs). Still, there is certainly room for improvement and continued research will help, in time.

Posted by: romine | June 9, 2009 1:39 AM | Report abuse

romine:
Thanks for your comments! You perfectly illustrate some of my points.

During the past 40 years, technological advances have vastly improved our ability to know what is occuring instantaneously with storm cells, but we don't have a clue regarding the status or trajectory 10,15,or 30 minutes into the future, hence more false alarms or warnings today compared to 10,20 or 40 years ago.

I have been somewhat amused with observations made from the services that I subscribe to which give immediate alerts, including map grids when the NWS or SPC issues any type of severe weather warning. Tornado or severe thunderstorm warnings have been issued for certain blocks of real estate in my area on many occasions that the general public never became aware of. These warnings are almost always incorrect because the storm pulses to a weaker status or different trajectory or location.

The radar enhancements of recent years such as storm tracker capability or predicter radar are also quite amusing, because they too are incorrect most of the time,resulting from the constant pulsing nature of these beasts. If far removed from a radar facility (my area), a close observer will be amaxed at how unreliable any type of radar is! The predicter models commonly incorporated into TV weathercasts are also incorrect the great majority of the time.

Most of the time, if a human makes the mistake of attempting to demonstrate publicly the operation of any new machine, procedure or capability without being thoroughly and intimately knowledgeable, they either appear to be a fool or detract from the intelligence or perceived usefulness of their product. Often the demonstrator will walk away, praying that no one was paying close attention!

To capsulize, we as a society have improved vision (new prescription lenses) today compared to 10,20 or 40 years ago. The problem is that we can't predict how our field of view will change short-term or long-term.

Will we ever?? Probably not to the degree that we aspire to. As romine also touched on, some of the games we play, are today and will be in the future, severely inhibited or restricted because of budgetary considerations.

Posted by: AugustaJim | June 9, 2009 8:21 AM | Report abuse

@ romine and augustajim

Your comments are right on. Even the best possible improvements in eyesight (phased array radars?) will only detect what's there at the moment of observation. Attempts to extrapolate radar observations even over the next 15 to 30 minutes have been largely unsuccessful. Thunderstorm complexes, including those which have the POTENTIAL to spawn tornadoes, do not just propagate straight line fashion, but continually evolve with older cells dying out and new ones developing. That process is not totally random, but largely unpredictable in detail.

We can probably do better in the foreseeable future in forecasting
the general region - perhaps county size - where severe weather is likely to break out.

In regard to false alarms, look at it this way. Storm chasers such as those participating in VORTEX2, are THE VERY BEST in forecasting where heavy weather is likely to occur. I don't know the statistics, but many, many more saddle ups to those locations are false alarms, not hits like the event Andrew reported.

Posted by: SteveT-CapitalWeatherGang | June 9, 2009 9:27 AM | Report abuse

SteveT:

Thanks very much! Your expert support is much appreciated!

Posted by: AugustaJim | June 9, 2009 9:56 AM | Report abuse

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