NOAA Office of Climate, Water, and Weather Services

During the early to middle 2000s, in response to demand for more detail in wind damage surveying and recordkeeping, a team of atmospheric scientists and wind engineers developed the enhanced Fujita (EF) scale. The EF scale, codified officially into National Weather Service (NWS) use in February 2007, offers wind speed estimates for a range of degrees of damage (DoDs) across each of 28 damage indicators (DIs). In practice, this has increased precision of damage surveys for tornado and thunderstorm-wind events. Still, concerns remain about both the representativeness of DoDs and the sufficiency of DIs, including the following: How dependable are the wind speed ranges for certain DoDs? What other DIs can be included? How can recent advances in mapping and documentation tools be integrated into the surveying process and the storm records? What changes should be made to the existing scale: why, how, and by whom? What alternative methods may be included or adapted for estimating tornado intensity? To begin coordinated discussion on these and related topics, interested scientists and engineers (including some involved in EF scale development) organized a national EF Scale Stakeholders' Meeting, held on 2–3 March 2010 in Norman, Oklahoma. This article presents more detailed background information, summarizes the meeting, presents possibilities for the future of the EF scale and damage surveys, and solicits ideas from the engineering and atmospheric science communities.

Despite flash flooding being one of the most deadly and costly weather-related natural hazards worldwide, individual datasets to characterize them in the United States are hampered by limited documentation and can be difficult to access. This study is the first of its kind to assemble, reprocess, describe, and disseminate a georeferenced U.S. database providing a long-term, detailed characterization of flash flooding in terms of spatiotemporal behavior and specificity of impacts. The database is composed of three primary sources: 1) the entire archive of automated discharge observations from the U.S. Geological Survey that has been reprocessed to describe individual flooding events, 2) flash-flooding reports collected by the National Weather Service from 2006 to the present, and 3) witness reports obtained directly from the public in the Severe Hazards Analysis and Verification Experiment during the summers 2008–10. Each observational data source has limitations; 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. 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. We envision the initiation of this community database effort will attract and encompass future datasets.

Abstract This study quantifies the skill of the National Weather Service’s (NWS) flash flood guidance (FFG) product. Generated by River Forecast Centers (RFCs) across the United States, local NWS Weather Forecast Offices compare estimated and forecast rainfall to FFG to monitor and assess flash flooding potential. A national flash flood observation database consisting of reports in the NWS publication Storm Data and U.S. Geological Survey (USGS) stream gauge measurements are used to determine the skill of FFG over a 4-yr period. FFG skill is calculated at several different precipitation-to-FFG ratios for both observation datasets. Although a ratio of 1.0 nominally indicates a potential flash flooding event, this study finds that FFG can be more skillful when ratios other than 1.0 are considered. When the entire continental United States is considered, the highest observed critical success index (CSI) with 1-h FFG is 0.20 for the USGS dataset, which should be considered a benchmark for future research that seeks to improve, modify, or replace the current FFG system. Regional benchmarks of FFG skill are also determined on an RFC-by-RFC basis. When evaluated against Storm Data reports, the regional skill of FFG ranges from 0.00 to 0.19. When evaluated against USGS stream gauge measurements, the regional skill of FFG ranges from 0.00 to 0.44.

The enhanced Fujita scale, devised to rate wind damage more precisely, will need accountability and flexibility to keep pace with advances in mapping, documentation, and the growing understanding of structural responses to airflow.

Abstract NOAA’s NWS implemented the new Local Climate Analysis Tool (LCAT) on 1 July 2013. The tool supports the delivery of climate services by quickly providing information to help with climate-sensitive decisions and to facilitate the development of local climate studies and assessments. LCAT provides its users with the ability to conduct local climate variability and change analyses using scientific techniques and the most trusted data, identified through consultation and approval with NOAA subject matter experts. LCAT data include climate-relevant surface observations for individual stations, regional divisions, and gridded reanalysis output. LCAT methods include trend-fitting techniques to assess the local rate of climate change, frequency and conditional probability analyses, and correlation studies to identify existing relationships between local climate and modes of climate variability, such as El Niño Southern Oscillation (ENSO). The tool produces customized output for individual users through a web-interface. These include graphical and tabular numeric data that can be either saved in the LCAT online environment or exported in standard formats for further analysis. For each query, LCAT provides an explanation for all graphical output to help users interpret the scientific results. LCAT also offers training modules explaining usability, data, scientific methods, and potential applications, with emphasis on the tool’s appropriate and inappropriate uses. Examples of LCAT applications include guidance for planning, resources management, and assessment purposes. LCAT has the potential for expansion to include a wide variety of datasets for broader application in environmental and socioeconomic decision support.

Abstract The NOAA Hydrometeorology Testbed (HMT) program has deployed a soil moisture observing network in the Babocomari River basin located in southeastern Arizona. The Babocomari River is a major tributary of the San Pedro River. At 0000 UTC 23 July 2008, the second-highest flow during the period of record was measured just upstream of the location where the Babocomari River joins the main channel of the San Pedro River. Upper-air and surface meteorological observations and Special Sensor Microwave Imager (SSM/I) satellite images of integrated water vapor were used to establish the synoptic and mesoscale conditions that existed before the flood occurred. The analysis indicates that a weak Gulf of California surge initiated by Hurricane Fausto transported a warm moist tropical air mass into the lower troposphere over southern Arizona, setting the stage for the intense, deep convection that initiated the flooding on the Babocomari River. Observations of soil moisture and precipitation at five locations in the basin and streamflow measured at two river gauging stations enabled the documentation of the hydrometeorological conditions that existed before the flooding occurred. The observations suggest that soil moisture conditions as a function of depth, the location of semi-impermeable layers of sedimentary rock known as caliche, and the spatial distribution of convective precipitation in the basin confined the flooding to the lower part of the basin. Finally, the HMT soil moisture observations are compared with soil moisture products from the NOAA/NWS/NCEP Noah land surface model.

In February 2008, the U.S. Joint Planning and Development Office (JPDO) for the Next Generation Air Transportation System issued an initial list of functional requirements for a NextGen network-enabled weather information system. The JPDO Weather Working Group then assembled an Environmental Information Team to oversee the further development of this document and to ensure that all of its observations and forecast data requirements are identified and clearly defined. Resolution requirements for traditional aviation weather hazards such as convective weather, in-flight icing, turbulence, volcanic ash are being developed. Observational scales of emerging problems for aviation in space weather and the environmental impacts of aviation are also being identified. Prior to this effort, an effort was begun by NOAA to comprehensively document the threshold and objective observational requirements for all of the required observables. To support this goal, scientists at NASA and NOAA conducted an extensive survey of the aviation weather research community. The results of this survey were used to help establish the baseline observational requirements for the Next Generation Air Transportation System (NextGen). Requirements for aviation weather observations had been originally codified by the NOAA NWS Office of Climate, Water, and Weather Services, Aviation Services Branch into a Consolidated Observations Requirements List (CORL) for Aviation (CT-AWX). The survey was conducted to update and expand the CORL CT-AWX to help develop a 4-D aviation weather information data base that will underpin NextGen. This information will also be employed by NOAA and NASA to inform the current operation and future development of research and operational observing systems. These comprehensive aviation observation requirements are also being developed to help support gap analyses for the aviation component of the Integrated Earth Observing System in order to inform the investment strategies of the FAA, NASA, and NOAA that are needed to develop the observational architecture to support NextGen and other users of high resolution environmental observations.

It is estimated that weather is responsible for approximately 70% of all air traffic delays and cancellations. Annually, this produces an overall economic loss of nearly $40B. These and other negative impacts on the U.S. National Airspace System will increase to the point of unsustainability unless the system is radically transformed. A Next Generation Air Transportation System (NextGen) was proposed to accommodate the increasing demand for capacity and the super-density operations that this transformation will entail. The heart of the environmental information component that is being developed for the new system will be a 4-dimensional data cube which will include a single authoritative source for NextGen Air Traffic Management (ATM) systems. Aviation weather constraints and safety hazards typically comprise meso-scale, stormscale as well as microscale observables. These include convective weather, in-flight icing, turbulence, volcanic ash, space weather and the environmental impacts of aviation. Functional and performance requirements for the NextGen weather system are being established that will require significant improvements in current observations and forecasting capabilities. This will include satellite observations from geostationary and/or polar-orbiting sounders, imagers, lightning mappers, space weather monitors and other environmental observing systems. In 2003, a Joint Planning and Development Office (JPDO) was established by public law to design and implement NextGen. This paper provides the satellite meteorology community with useful insight on salient NextGen environmental information requirements that have been developed by the JPDO Weather Working Group. These efforts will help to shape current and future environmental satellite system capabilities, operations and applications. ____________________ Corresponding author address: John Murray, NASA Langley Research Center, MS 401-B, 21 Langley Blvd., Hampton, VA 23681. E-mail: john.j.murray@nasa.gov

Recent changes in the organizational structure of the National Oceanic and Atmospheric Administration (NOAA) have created an environment conducive to improved end-to-end agency climate data stewardship. Changes include the reintroduction of a climate services program into the National Weather Service (NWS) through the creation of a Climate Services Division (CSD) at the headquarters level, the creation of a NWS liaison at the National Climatic Data Center (NCDC), and the addition of six Regional Climate Centers as contractual support for NCDC.