Scientists re-visit the Tri-State Tornado

desotorbThe March 18, 1925 Tri-State Tornado was unusually severe, killing 695 people while it was on the ground for a record 219 miles crossing parts of Missouri, Illinois and Indiana. Unfortunately, there is only one formal paper regarding the tornado and its meteorological setting.

A team of eight severe storms meteorologists re-analyzed the event using all relevant U.S. Weather Bureau data on the Tri-State Tornado.  The results, published in the Electronic Journal of Severe Storms Meteorology, revealed previous analyses of the surface weather conditions were inaccurate and led to misconceptions about where the tornado formed in reference to the existing weather system.  The authors include retired NSSL Director Bob Maddox, retired NSSL/CIMMS researchers Chuck Doswell, Don Burgess and Charlie Crisp, retired Storm Prediction Center (SPC) meteorologist Bob Johns and current SPC meteorologist John Hart, and Steve Piltz from the National Weather Service Forecast Office in Tulsa, Okla.

The researchers concluded there was no singular feature in the meteorological setting that would explain the extreme character of the Tri-State tornado.  The storms of 18 March were associated with a rapidly moving cyclone that was not unusually intense.  The new analyses show a long-lived supercell that developed very near the center of the cyclone produced the tornado, possibly where a warm front and a distinct dryline intersected.  The south-to-north temperature gradient was very pronounced due to cooling produced by early morning storms and precipitation.  The tornadic supercell tracked at an average speed of 59mph moving farther away from the cyclone center with time.  And, the storm remained very close to the surface warm front.

Researchers did find as the supercell and dryline moved rapidly eastward, the northward advance of the warm front kept the tornadic supercell within a very favorable storm environment for several hours.  It appears this consistent time and space connection of the supercell, warm front, and dryline was extremely unusual.

With reanalysis beginning 70 years after the tornado, it was impossible to confirm the complete continuity of the damage path along the reported path.  Even with extensive field work discovering 2,395 individual damage points, there were 32 gaps of at least one mile in length, but only 7 gaps longer than 2.5 miles in length.  All of the longer gaps were in the Missouri portion of the path; within the sparsely-populated Ozark mountain area.  Assuming that gaps shorter than 2.5 miles might still represent a continuous tornado, the continuous path was at least 174 miles long.  Additional, previously unreported tornadoes were also found before the beginning and after the end of the Tri-State Tornado.  The research also allowed for conclusion that the storm was a supercell; classic in its stages and high-precipitation in the later stages.  The supercell also produced accompanying hail up to baseball size and non-tornadic damaging winds.

http://www.ejssm.org/ojs/index.php/ejssm/issue/archive

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Renowned physicist to speak at National Weather Center

Slakey to speak at NWC
Slakey to speak at NWC

The National Weather Center will host renowned physicist Dr. Francis Slakey, Associate Director of Public Affairs at the American Physical Society, at 4 p.m. April 23 in Room 1313. Slakey ‘s topic is also the title of his book, “To the Last Breath – A Memoir of Going to Extremes.” The book is on Amazon’s “2012 Best Books of the Year” list.

In 2009, Slakey became the first person to summit the highest mountain on every continent and surf every ocean (including the Arctic) on Earth. He plans to share how he used the laws of physics to his advantage in his climbing expeditions and the knowledge of the geophysics of waves to surf. He will also talk about how his adventures led him on a path to address global challenges such as climate change. For years Slakey has inspired students and researchers across the nation to address societal challenges through science and motivated them to turn their ideas into legislation.

This seminar is part of a new “Science Policy and Its Significance to Weather, Water and Climate” class offered by the University of Oklahoma and taught by NSSL /CIMMS research meteorologist Subhashree Mishra. Speakers include:

– Harold Brooks, NSSL Research Meteorologist

– Mike Douglas, NSSL Research Meteorologist

– Pam Heinselman, NSSL Research Meteorologist

– Kevin Kelleher, NSSL deputy director

– Edwin Kessler, retired NSSL director

– Pete Lamb, CIMMS director

More information is available here: http://som.ou.edu/seminars/

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Recent significant papers released online

(OAR National Severe Storms Laboratory and Cooperative Institute for Mesoscale Meteorological Studies) Tornado path length forecasts from 2010 – 2011 using ensemble updraft helicity

Journal:  Weather and Forecasting (Early online release 1/14/13)

Authors:  Adam J. Clark, (CIMMS/NSSL) Jidong Gao,(NSSL) Patrick T. Marsh, (CIMMS/NSSL) Travis Smith, (CIMMS/NSSL) John S. Kain,(NSSL) James Correia, Jr., Ming Xue, and Fanyou Kong

Summary
This paper adds new data to previous research that diagnosed a strong relationship between the cumulative path lengths of simulated rotating storms (measured using a 3-dimensional object identification algorithm applied to forecast updraft helicity) and the cumulative path lengths of tornadoes. The new forecast examples are from three major 2011 tornado outbreaks – 16 and 27 April, and 24 May, as well as two forecast failure cases from June 2010. Finally, analysis updraft helicity from 27 April 2011 is computed using a three-dimensional variational data assimilation system to obtain 1.25 km grid-spacing analyses at 5-minute intervals and compared to forecast UH from individual SSEF members.

Important conclusions:   Forecast updraft helicity pathlengths during the spring could be a very skillfull predictor for the severity of tornado outbreaks as measured by total pathlengths.

Significance:  Efforts continue to find better ways to predict tornadoes and tornado outbreaks  Weather and Forecasting (Early online release 1/14/13)

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(OAR-National Severe Storms Laboratory) A Unified Flash Flood Database over the US

Journal:  Bulletin of the American Meteorological Society (early online release 1/25/13)

Authors:  Jonathan J. Gourley (NSSL), Yang Hong, Zachary L. Flamig (NSSL), Ami Arthur (NSSL/CIMMS), Robert Clark (NSSL/CIMMS), Martin Calianno, Isabelle Ruin, Terry Ortel, Michael E. Wieczorek, Pierre-Emmanuel Kirstetter (NSSL), Edward Clark, Witold F. Krajewski

Summary:  This study is the first of its kind to assemble, reprocess, describe, and disseminate a georeferenced US database providing a long-term, detailed characterization of flash flooding in terms of spatiotemporal behavior and specificity of impacts. The database is comprised of three primary sources: 1) the entire archive of automated discharge observations from the US Geological Survey that has been reprocessed to describe individual flooding events, 2) flash flooding reports collected by the National Weather Service from 2006-present, and 3) witness reports obtained directly from the public in the Severe Hazards Analysis and Verification Experiment during the summers 2008–2010.

Important conclusions:  A major asset of the unified flash flood database is its collation of relevant information from a variety of sources that is now readily available to the community in common formats.

Significance:  It is anticipated that this database will be used for many diverse purposes such as evaluating tools to predict flash flooding, characterizing seasonal and regional trends, and improving understanding of dominant flood-producing processes.   Bulletin of the American Meteorological Society (early online release 1/25/13)

Authors:  Jonathan J. Gourley (NSSL), Yang Hong, Zachary L. Flamig (NSSL), Ami Arthur (NSSL/CIMMS), Robert Clark (NSSL/CIMMS), Martin Calianno, Isabelle Ruin, Terry Ortel, Michael E. Wieczorek, Pierre-Emmanuel Kirstetter (NSSL), Edward Clark, Witold F. Krajewski

Summary:  This study is the first of its kind to assemble, reprocess, describe, and disseminate a georeferenced US database providing a long-term, detailed characterization of flash flooding in terms of spatiotemporal behavior and specificity of impacts. The database is comprised of three primary sources: 1) the entire archive of automated discharge observations from the US Geological Survey that has been reprocessed to describe individual flooding events, 2) flash flooding reports collected by the National Weather Service from 2006-present, and 3) witness reports obtained directly from the public in the Severe Hazards Analysis and Verification Experiment during the summers 2008–2010.

Important conclusions:  A major asset of the unified flash flood database is its collation of relevant information from a variety of sources that is now readily available to the community in common formats.

Significance:  It is anticipated that this database will be used for many diverse purposes such as evaluating tools to predict flash flooding, characterizing seasonal and regional trends, and improving understanding of dominant flood-producing processes.

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Evolution of a Quasi-Linear Convective System Sampled by Phased Array Radar

Journal: Monthly Weather Review

Expected publication date: Early online release, June 5, 2012

Authors: Jennifer Newman, Pamela Heinselman (NSSL)

Summary: The National Weather Radar Testbed Phased Array Radar in Norman, Oklahoma scanned a strong line of thunderstorms as it produced damaging wind events across central Oklahoma. The rapid scanning phased array radar created a detailed depiction of these wind events including microbursts, an intensifying midlevel jet, and a small area of rotation.

Important conclusions: The depiction of these events in the phased array radar data demonstrates the complex and rapidly changing nature of strong
lines of thunderstorms.

Significance: Using rapid-scan phased array radar, developing severe weather is easier to detect and important changes in the strength of storms can be
revealed.

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NSSL researchers to present at AMS annual meeting

NSSL staff are preparing to receive honors and present recent research at the 2012 American Meteorological Society (AMS) Annual Meeting in New Orleans, La., Jan. 21-26.

NSSL storm electricity expert Don MacGorman has been elected an AMS Fellow and will be honored at the meeting.

The NOAA Hazardous Weather Testbed Team, including NSSL’s Mike Coniglio and Jack Kain, will receive the Kenneth C. Spengler Award for bringing the government, academic, and private sectors together in a visionary, proactive, and exemplary manner to deal with the challenges posed by hazardous weather.

Presentations and poster topics include a new high-resolution forecast model, a way to use cloud properties retrieved from GOES in forecasts, a weather-adaptive system that can help forecasters detect and analyze severe weather, and evaluation results from forecasters participating in the NOAA Hazardous Weather Testbed.  New phased array radar research, techniques to solve radar problems, studies of cloudiness tendencies, and NOAA outreach at the National Weather Center are also on the agenda.

An NSSL researcher is serving on an expert panel about the future of dual-polarization radar research, and several NSSL staff will serve as session chairs.

NSSL will also host a booth at “WeatherFest,” an annual weather science fair open to the public.

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NSSL research to be presented at 6th European Conference on Severe Storms

NSSL researchers are presenting at the 6th European Conference on Severe Storms (ECCS) in Palma de Mallorca, Balearic Islands, Spain from October 3-7, 2011.

The ECCS is an opportunity for the international scientific community to exchange the newest developments in severe storm research. Strong winds, hail, flooding and tornadoes are common in many European countries, leading to a total damage estimate of 5 to 8 billion Euros per year. While meteorological conditions leading to severe thunderstorm occurrences in Europe are similar to those observed in the USA and elsewhere, they differ in detail, especially with regard to mesoscale characteristics such as terrain-induced circulations. A better knowledge of European severe thunderstorms storms could bring new insights into severe storm dynamics and forecasting worldwide.

NSSL lead-author topics include:  “Progress and challenges with Warn-on-Forecast,”  “Initial results from convective-scale analysis and prediction of the 14 June 2011 Norman Oklahoma macroburst using conventional and rapid-scan weather Doppler radar data,” “Comparisons of kinematical retrievals within a simulated supercell: Dual-Doppler analysis vs. EnKF data assimilation, and “Severe thunderstorms and climate change.”

The ECCS is organized by ESSL and a local partner at varying locations across Europe and the Mediterranean every two years, and is supported by the European Meteorological Society. The last ECSS conference in Landshut (Germany) in 2009, had an attendance of 207 people from 41 countries, including Japan, the USA, and India. The 6th European Conference on Severe Storms is sponsored by the European Severe Storms Laboratory, established in 2006 and modeled after NSSL.

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NSSL/CIMMS researchers to present at international symposium

NSSL/CIMMS researchers will be presenting at the 2nd International Symposium on Earth-science Challenges (ISEC) at the National Weather Center (NWC) in Norman, Okla. on September 14-16, 2011. This biannual event is dedicated to bringing together scientists and engineers from around the world to share recent advances in the study of the Earth.

Participating researchers will be giving oral and poster scientific presentations on earth system science, radar and satellite remote sensing of the atmosphere, hydrometeorology, modeling and data assimilation, and weather and climate variability.

The event is sponsored by Kyoto University (KU),and the University of Oklahoma (OU).

http://arrc.ou.edu/ouku-sym/

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NSSL researchers to present at AMS meeting

NSSL researchers will be presenting at the 39th American Meteorological Society Conference on Broadcast Meteorology and Conference on Weather Warnings and Communication June 22-24 in Oklahoma City, Okla.

NSSL presentations include:

“Sports-Like Coverage of Storms by Phased Array Radar”

“The Polarimetric Upgrade to the NWS WSR-88D Network:  An Overview of Data and Products Available to Operational Forecasters”

“The Tornado Vortex Signature”

“Role-Playing Scenario of a Landfalling Tropical System”

“NOAA Hazardous Weather Testbed Experimental Warning Program”

Lessons Learned and Future Goals for High-Resolution Severe Storm Verification at NSSL”

“Managing Media Interactions During VORTEX2 – Lessons Learned”

Also, an NSSL scientist will be sitting on a panel discussing:  “Communicating Disaster:  Insights, Lessons, and Lingering Questions from the Deadliest Tornado Year in Decades”

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Recent lead-author publications

Heinselman, P. L., S. M. Torres, 2011: High-temporal-resolution capabilities of the National Weather Radar Testbed Phased-Array Radar. Journal of Applied Meteorology and Climatology, 50, 579-593.

Kumjian, M. R., A. V. Ryzhkov, 2011: Polarimetric radar signatures in supercell storms. Proc. National Radio Science Meeting 2011, Boulder, CO, USA, U.S. National Committee of the International Union of Radio Scie, 1096.

Lewis, J. M., M. L. Kaplan, R. K. Vellore, R. M. Rabin, J. Hallett, S. A. Cohn, 2011: Dust Storm over the Black Rock Desert: Larger-scale Dynamic Signatures. Journal of Geophysical Research – D: Atmospheres, 116, 1-23, doi:Current available in AGU Paper.

Smith, T. M., V. Lakshmanan, 2011: Real-time, rapidly updating severe weather products for virtual globes. Computers and Geosciences, 37, 3-12, doi:10.1016/j.cageo.2010.03.023.

Turner, D. D., P. J. Gero, 2011: Downwelling infrared radiance temperature climatology for the Atmospheric Radiation Measurement Southern Great Plains site. Journal of Geophysical Research – D: Atmospheres, 116, D08212, doi:10.1029/2010JD015135.

Willingham, K. M., E. J. Thompson, K. W. Howard, C. L. Dempsey, 2011: Characteristics of Sonoran Desert Microbursts. Weather and Forecasting, 26, 94-108, doi:10.1175/2010WAF2222388.1.

Wood, V. T., 2011: Testing of a new parametric tropical cyclone wind model for implementation in the gradient wind asymmetric vortex algorithm (GWAVA) to drive storm surge prediction models. Proc. 65th Interdepartmental Hurricane Conference, Miami, FL, USA, OFCM (Office of the Federal Coordinator for Meteorological Servi, P24.

Xu, Q., K. Nai, L. Wei, P. Zhang, S. Liu, D. Parrish, 2011: A VAD-based dealiasing method for radar velocity data quality control. Journal of Atmospheric and Oceanic Technology, 28, 50-62.

Zrnic, D. S., G. Zhang, R. J. Doviak, 2011: Bias correction and Doppler measurement for polarimetric phased-array radar. IEEE Transactions on Geoscience and Remote Sensing, 49, 843-853.

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Science journal publishes article on weather radar tracking bats

The 25 February 2011 Volume 331 issue of Science, a publication of the American Association for the Advancement of Science published the following article:

Researchers Use Weather Radar to Track Bat Movements

A new field of study called aeroecology looks at the interactions between flying animals and their airspace. Using weather radars, a bat ecologist has discovered that the weather strongly affects the behavior of at least one species. Brazilian free-tailed bats, common in the south-central United States and Mexico, emerge from their daytime slumber at different times of day depending on the temperature, she and her colleagues reported on 19 February at the AAAS annual meeting (see p. 995 and here for more meeting coverage).

http://www.sciencemag.org/content/331/6020/998.summary

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