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Uwe Radok
and
Timothy J. Brown

Abstract

The “anomaly correlation” between a predicted time series and a verifying series, both of which have had the same climatic history subtracted, combines their “direct” correlation with their two climate correlations and with the variance of the historical series. The direct correlation can be freed of climatic effects to become the “partial” correlation, which therefore seems a better parameter for judging predictive skill.

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John T. Abatzoglou
and
Timothy J. Brown

Abstract

Summertime cloud-to-ground lightning strikes are responsible for the majority of wildfire ignitions across vast sections of the seasonally dry western United States. In this study, a strong connection between active phases of the Madden–Julian oscillation (MJO) and regional summertime lightning activity was found across the interior western United States. This intraseasonal mode of lightning activity emanates northward from the desert Southwest across the Great Basin and into the northern Rocky Mountains. The MJO is shown to provide favorable conditions for the northward propagation of widespread lightning activity through the amplification of the upper-level ridge over the western United States and the development of midtropospheric instability. Given the relative predictability of the MJO with long lead times, results allude to the potential for intraseasonal predictability of lightning activity and proactive fire management planning.

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John A. Flueck
and
Timothy J. Brown

Abstract

Research criteria and methods are presented for performing and evaluating the growing discipline of solar-weather studies. A clear distinction among preliminary, exploratory, and confirmatory studies is presented, and it is shown that this distinction affects all dimensions and findings of a study. Particular attention is given to conceptual models, variables and data, sample designs, analyses, and formal ampliative inference issues under exploratory and confirmatory conditions. The utility of the proposed criteria and methods are illustrated by evaluating two recent solar-weather claims of strong association between solar flux and stratospheric temperature at the North Pole when partitioned by the phase of the quasi-biennial oscillation. The results of the evaluation indicate that these claims are only exploratory ones and are still in need of confirming evidence. Last, a reanalysis of the solar flux and temperature relation, using some of the proposed methods, indicates that the association actually changes with time, and thus, there appears to be other, presently unknown, factors that affect this potential solar-weather relation.

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Timothy J. Brown
and
Beth L. Hall
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Tamara U. Wall
,
Timothy J. Brown
, and
Nicholas J. Nauslar

Abstract

Spot weather forecasts (SWFs) are issued by Weather Service offices throughout the United States and are primarily for use by wildfire and prescribed fire practitioners for monitoring local-scale weather conditions. This paper focuses on use of SWFs by prescribed fire practitioners. Based on qualitative, in-depth interviews with fire practitioners and National Weather Service forecasters, this paper examines factors that influence perceptions of accuracy and utilization of SWFs. Results indicate that, while several well-understood climatological, topographical, and data-driven factors influence forecast accuracy, social factors likely have the greater impact on perceptions of accuracy, quantitative accuracy, and utilization. These include challenges with building and maintaining relationships between forecasters and fire managers, communication issues around updating SWFs, and communicating forecast confidence and uncertainty. Operationally, improved quantitative skill in a forecast is always desirable, but key opportunities for improving accuracy and utilization of these forecasts lie in 1) enhancing the processes and mechanisms for communication between a Weather Forecast Office and fire practitioners—before, during, and after an SWFs is issued—and 2) working with the wildland fire community to experiment with forecast uncertainty and confidence information in SWFs and evaluate impacts of these approaches.

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Timothy J. Brown
,
L. Mark Berliner
,
Daniel S. Wilks
,
Michael B. Richman
, and
Christopher K. Wikle

Analyses of atmospheric sciences data and models are heavily dependent upon statistical and probabilistic reasoning. Statistical methods have played an important role in establishing physical relationships of atmosphere–ocean–land interactions and in the development and verification of numerical forecast models. There is no reason to expect statistics to play a lesser role in the years ahead. Yet there has been and remains minimal formal training in statistics and probability for atmospheric sciences students in the United States. This is in sharp contrast to other fields such as the social sciences. This paper describes issues surrounding the general weakness in formal statistics education for both undergraduate and graduate atmospheric sciences students, and the minimal collaboration between statisticians and atmospheric scientists. Recommendations are offered on statistics curriculum guidelines for undergraduate and graduate atmospheric sciences students, and on improving the overall interaction between the statistics and atmospheric sciences disciplines.

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David L. Mitchell
,
Dorothea Ivanova
,
Robert Rabin
,
Timothy J. Brown
, and
Kelly Redmond

Abstract

Perhaps the most regular and predictable weather pattern in North America is the North American (NA) or Mexican monsoon. Occurring in summer, it delivers about 35% and 45% of Arizona's and New Mexico's annual precipitation, respectively, and about 60% of northern Mexico's. While recent studies have linked strong NA monsoons to summer drought in the U.S. Midwest, the sequence of events that produce the NA monsoon remain unclear.

This empirical study builds on the findings of many other studies that implicate the Gulf of California [(GOC) or simply the gulf] as the dominant moisture source for the monsoon. It examines six monsoon seasons in detail, and quantitatively relates GOC sea surface temperatures (SST) to the timing, amount, and regional extent of monsoon rainfall.

This six season study is based on satellite measurements of rainfall [using the Special Sensor Microwave Imager (SSM/I)] and GOC SST at high spatial and temporal resolution. Key findings include the following. 1) Monsoon rainfall did not occur prior to the onset of GOC SSTs exceeding 26°C, and the incremental advance of SSTs > 26°C up the mainland coast of Mexico appears necessary for the northward advance of the monsoon. 2) For the period June–August, 75% of the rainfall in the Arizona–New Mexico region (AZNM) occurred after northern GOC SSTs exceeded 29°C, with relatively heavy rains typically beginning 0–7 days after this exceedance. 3) For a given year, SSTs in the southern and central GOC reached 29.5°C during a similar time frame, but such warming was delayed in the northern GOC. This warming delay coincided with a rainfall delay for AZNM relative to regions farther south. 4) Based on the 17 yr of available SST data, 14 of those years exhibited the following behavior: When northern gulf SSTs were relatively high for some period during the first half of July, rainfall during June–August in Arizona was relatively high. Otherwise, June–August Arizona rainfall was normal or below normal. 5) Anomalously wet July–September periods in Arizona do not correspond to anomalously wet periods in New Mexico, based on data from 1950 to the present. The wettest Arizona seasons, about 1.1 standard deviations wetter than normal, were strongly related to summer drought in the Midwest, being about 0.8 standard deviations drier than normal. This was not true for the wettest New Mexico years (Midwest rainfall was near normal), but these years exhibited dry conditions in the interior Northwest, with standard deviations being about 0.6–0.9 drier than normal. Collectively, this research suggests that the cause of these two wet monsoon modes may be related to SSTs in the northern gulf, which appear to affect Arizona more than New Mexico rainfall.

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Gigi Owen
,
Jonathan D. McLeod
,
Crystal A. Kolden
,
Daniel B. Ferguson
, and
Timothy J. Brown

Abstract

Continuing progress in the fields of meteorology, climatology, and fire ecology has enabled more proactive and risk-tolerant wildland fire management practices in the United States. Recent institutional changes have also facilitated the incorporation of more advanced climate and weather research into wildland fire management. One of the most significant changes was the creation of Predictive Services in 1998, a federal interagency group composed, in part, of meteorologists who create climate- and weather-based fire outlooks tailored to fire manager needs. Despite the numerous forecast products now available to fire managers, few studies have examined how these products have affected their practices. In this paper the authors assess how fire managers in the Southwest region of the United States perceive and incorporate different types of information into their management practices. A social network analysis demonstrates that meteorologists have become central figures in disseminating information in the regional interagency fire management network. Interviews and survey data indicate that person-to-person communication during planning phases prior to the primary fire season is key to Predictive Services’ success in supporting fire managers’ decision making. Over several months leading up to the fire season, predictive forecasts based on complex climate, fuels, and fire-risk models are explained to fire managers and updated through frequent communication. The study’s findings suggest that a significant benefit of the information sharing process is the dialogue it fosters among fire managers, locally, regionally, and nationally, which better prepares them to cooperate and strategically plan for the fire season.

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Toward Regional Climate Services

The Role of NOAA's Regional Climate Centers

Arthur T. DeGaetano
,
Timothy J. Brown
,
Steven D. Hilberg
,
Kelly Redmond
,
Kevin Robbins
,
Peter Robinson
,
Martha Shulski
, and
Marjorie McGuirk

For 25 yr, the Regional Climate Center (RCC) program has provided climate services to six regions encompassing the United States. The service provided by the RCCs has evolved through this time to become an efficient, user-driven program that exemplifies many of the components that have been cited for effective national climate services. To illustrate the RCCs' role as operational climate service providers, a brief history of the program is presented with recent examples of RCC innovations in the provision and creation of data products and decision tools, computer infrastructure, and the integration of climate data across networks. These strengths complement the missions of other federal climate service providers and regional and state-based programs, such as the Regional Integrated Sciences and Assessments, state climatologist programs, and National Weather Service climate services program managers and local focal points with which the RCCs actively partner.

Building on this expertise, a vision for the RCC role in climate services during the next quarter century is presented. This strategy includes five main components encompassing 1) operational linkage of an array of climate data sources with climate products, tools, and monitoring systems; 2) engagement of new and existing climate service partners to reduce the risk associated with climate impacts; 3) implementation of innovative user-driven approaches to regional and local climate services; 4) climate data stewardship; and 5) scientifically sound assessments and solutions to climate-related problems through active stakeholder collaboration and engagement. These elements will be equally applicable and important to decisions related to the historical climate record, real-time interannual climate variations, or future climate change assessment and adaptation activities.

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Natalie A. Umphlett
,
Timothy J. Brown
,
Charles E. Konrad
,
Tamara U. Wall
,
Beth L. Hall
,
Arthur T. DeGaetano
,
John W. Nielsen-Gammon
,
Rezaul Mahmood
, and
Tamara G. Houston

Abstract

Since its inception in 1983, NOAA’s Regional Climate Center (RCC) Program has been providing timely, customized climate services for decision making across all climate-sensitive sectors. Through this 40-yr period, the RCC Program has not only seen but also has played an active role in, the evolution of climate services from the days of climate data libraries—where books of data were consulted to fulfill simple data requests—to coproduced tools that can calculate sectoral-specific, on-the-fly climate analyses in a matter of seconds. With new technologies emerging, the RCC Program is poised to build on its reputation as a trusted climate service provider by incorporating advanced methods for climate service delivery to continue to meet the needs of the nation. This publication will provide a look back at the evolution of regional climate services over the past 40 years, along with a vision for the future.

Open access