by Jason Shafer, Ph.D.
The Forensic Meteorologist — “Reconstructing Weather”
When Tropical Storm Irene was lurking,
meteorologists knew well ahead of time that there was going to be trouble. Weath- er forecast models up to five days ahead showed a consistent scenario of very heavy rainfall to the left of Irene’s track, a pattern often observed with tropical systems as they move into the Northeast United States and interact with middle latitude frontal systems. While Irene’s track was fairly well forecast, the magnitude of the flooding im- pacts were difficult to determine. This was likely due to a variety of factors, including the rarity of the event in human forecaster experience, and uncertainties in the hydro- logic response. Over the hardest hit areas, Irene’s impacts reached a 200-year flood, exceeding the impacts of the Great Flood of 1927. Irene’s track was controlled by the large- scale position of upper-level features thou- sands of miles away from her center. All weather is controlled by such large scale processes, but ultimately the weather we experience is local or small scale. Vermont’s complex terrain helps to accentuate these local contrasts, further motivating the need for a skilled forensic meteorologist to de- termine weather conditions surrounding high-impact events.
The intention of this article is to highlight the work of forensic meteorology, and the process by which meteorologists may re- construct site-specific weather conditions surrounding high-impact events.
Meteorologist Training Forensic meteorology is a very small, but
growing, subfield of meteorology. There are no such degree programs, and only a handful of institutions offer related cours- es. Forensic meteorologists are trained me- teorologists who seek to apply their analy- sis skills to reconstructing weather events, usually related to civil or criminal lawsuits. In the United States there are only 126 Cer- tified Consulting Meteorologists with a specialty in Forensic Meteorology.1 Meteorologists undergo extensive stud- ies and training to develop the skills to ana- lyze and forecast the weather. A bachelor’s degree is the minimum required educa- tion, with approximately 25% of graduates attaining post-graduate education. Exten- sive course work in math (e.g., calculus) and sciences (e.g., physics), and numerous specialty courses such as Atmospheric Dy- namics are standard. At Lyndon State Col-
www.vtbar.org
Figure 1. Surface weather station observations in Vermont reporting hourly temperatures. Courtesy MesoWest,
http://www.mesowest.utah.edu.
lege, for example, Atmospheric Sciences is considered a professional studies program, with over 60% of required degree credit in the major. Lyndon State is the only Vermont institution offering such a degree, and one of approximately twenty accredited U.S. in- stitutions with a solely undergraduate At- mospheric Sciences/Meteorology degree program. You likely get your weather fore- casts from our alumni. Approximately half of the meteorologists
in the United States are employed by the public sector primarily within the Nation- al Weather Service, while the other half is employed within the private sector. Private sector employment includes broadcast me- teorologists, numerous small companies,
THE VERMONT BAR JOURNAL • WINTER 2012
and other niche positions. Increasing fore- casting skill and awareness of weather and climate-related economic risks have driven strong job growth within the private sector in the last fifteen years, including forensic meteorology.
Weather Data and Value Added Analysis
Forensic meteorologists have a wealth of data and analysis techniques to assess prior weather conditions. The National Cli- matic Data Center (NCDC) archives numer- ous datasets, everything from Doppler ra- dar data to surface weather observations.2 In addition, academic institutions host oth- er value-added data archives. This data is
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