Seasonal Temperature Forecasts as Products of Antecedent Linear and Spatial Temperature Arrays

Our objective is to evaluate the potential for extracting the maximum information contained in antecedent temperature patterns that operationally could be used in formulating winter seasonal forecasts in the United States. In particular, examination of the predictability of winter temperatures given autumn temperatures is made using derived contingency tables, discriminant equations of antecedent principal components, and canonical correlation analysis. Contingency tables were constructed based on tercile classifications of a seventy-five-year dependent record (1895-1969). Testing of an independent data period (1970-78) using these tables produced winter forecasts with no appreciable skill in the aggregate (-0.04). Discriminant analysis derived linear combinations of the five principal components of the antecedent seasonal (autumn) temperatures to distinguish between specific terciles of the predictand season (winter). Despite encouraging results for the dependent period, forecast skill for the independent test period achieved no significant score (-0.04). Unfortunately, both of these forms of analysis suffer imposed spatial limitations which restrict the scope of our investigation. Canonical correlation analysis is capable of relating the total spatial variance of fall temperatures to that of the winter temperatures for the entire United States. In this study, the technique was used to isolate seasonal patterns in winter temperature data that are correlated in time with fall temperature patterns for the same region. Summation of the first 20 canonical variate pairs suggests that autumn and winter temperatures over the continental United States are not closely related to one another

New WMO certified megaflash lightning extremes for flash distance (768 km) and duration (17.01 seconds) recorded from space

Initial global extremes in lightning duration and horizontal distance were established in 2017 (Lang et al. 2017) by an international panel of atmospheric lightning scientists and engineers assembled by the WMO. The subsequent launch of NOAA’s latest GOES-16/17 satellites with their Geostationary Lightning Mappers (GLMs) enabled extreme lightning to be monitored continuously over the western hemisphere up to 55° latitude for the first time. As a result, the former lightning extremes were more than doubled in 2019 to 709 km for distance and 16.730 s for duration (Peterson et al. 2020). Continued detection and analysis of lightning “megaflashes” (Sequin, 2021) has now revealed two flashes that even exceed those 2019 records. As part of the ongoing work of the WMO in detection and documentation of global weather extremes (e.g., El Fadli et al. 2013; Merlone et al. 2010), an international WMO evaluation committee was created to critically adjudicate these two GLM megaflash cases as new records for extreme lightning.We thank S. A. Rutledge and two other reviewers for their valuable comments. M. J. Peterson was supported by the U.S. Department of Energy through the Los Alamos National Laboratory (LANL) Laboratory Directed Research and Development (LDRD) program under project number 20200529ECR. Los Alamos National Laboratory is operated by Triad National Security, LLC, for the National Nuclear Security Administration of U.S. Department of Energy (Contract 89233218CNA000001). T. Logan supported by a NOAA Grant NA16OAR4320115 “Lightning Mapper Array Operation in Oklahoma and the Texas Gulf Coast Region to Aid Preparation for the GOES-R GLM.” I. Kolmasova was supported by GACR Grant 20-09671. S. D. Zhang was supported by a NOAA Grant NNH19ZDA001N-ESROGSS. The participation of J. Montanya in this work is supported by research Grant ESP2017-86263-C4-2-R funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe,” by the “European Union”; and Grants PID2019-109269RB-C42 funded by MCIN/AEI/10.13039/501100011033.Peer ReviewedPostprint (author's final draft

WMO evaluation of northern hemispheric coldest temperature: −69.6 °C at Klinck, Greenland, 22 December 1991

A World Meteorological Organization (WMO) Extremes Evaluation Committee investigated an observation of −69.6 °C by Klinck Automatic Weather Station (AWS) in Greenland on 22 December 1991 as the lowest temperature observed in Greenland, thereby making it the lowest recorded near‐surface air temperature for the Northern and Western Hemispheres and for WMO Region VI. The committee examined the metadata and observations of the station as well as the regional synoptic circulation. The committee concluded that the observation is credible in terms of instrument calibration, monitoring of the station and the synoptic situation. Consequently, the WMO Rapporteur accepted the observation as the officially lowest observed near‐surface air temperature for Greenland, the Northern and Western Hemisphere and for WMO Region VI. As a supplement to this investigation, the committee also recommends that opportunities be investigated such that AWS data from Greenland can be efficiently incorporated into real‐time weather forecasts and hence into reanalysis datasets

Evaluating the highest temperature extremes in the antarctic

The record high temperature for regions south of 60°S latitude is a balmy 19.8°C (67.6°F), recorded 30 January 1982 at a research station on Signy Island

WMO assessment of weather and climate mortality extremes : lightning, tropical cyclones, tornadoes, and hail

A World Meteorological Organization (WMO) Commission for Climatology international panel was convened to examine and assess the available evidence associated with five weather-related mortality extremes: 1) lightning (indirect), 2) lightning (direct), 3) tropical cyclones, 4) tornadoes, and 5) hail. After recommending for acceptance of only events after 1873 (the formation of the predecessor of the WMO), the committee evaluated and accepted the following mortality extremes: 1) ''highest mortality (indirect strike) associated with lightning'' as the 469 people killed in a lightning-caused oil tank fire in Dronka, Egypt, on 2 November 1994; 2) ''highest mortality directly associated with a single lightning flash'' as the lightning flash that killed 21 people in a hut in Manica Tribal Trust Lands, Zimbabwe (at time of incident, eastern Rhodesia), on 23 December 1975; 3) ''highest mortality associated with a tropical cyclone'' as the Bangladesh (at time of incident, East Pakistan) cyclone of 12-13 November 1970 with an estimated death toll of 300 000 people| 4) ''highest mortality associated with a tornado'' as the 26 April 1989 tornado that destroyed the Manikganj district, Bangladesh, with an estimated death toll of 1300 individuals| and 5) ''highest mortality associated with a hailstorm'' as the storm occurring near Moradabad, India, on 30 April 1888 that killed 246 people. These mortality extremes serve to further atmospheric science by giving baseline mortality values for comparison to future weather-related catastrophes and also allow for adjudication of new meteorological information as it becomes available.https://www.ametsoc.org/ams/index.cfm/publications/journals/weather-climate-and-society2018-01-30hj2017Geography, Geoinformatics and Meteorolog

Seasonal Temperature Forecasts as Products of Antecedent Linear and Spatial Temperature Arrays

Our objective is to evaluate the potential for extracting the maximum information contained in antecedent temperature patterns that operationally could be used in formulating winter seasonal forecasts in the United States. In particular, examination of the predictability of winter temperatures given autumn temperatures is made using derived contingency tables, discriminant equations of antecedent principal components, and canonical correlation analysis. Contingency tables were constructed based on tercile classifications of a seventy-five-year dependent record (1895-1969). Testing of an independent data period (1970-78) using these tables produced winter forecasts with no appreciable skill in the aggregate (-0.04). Discriminant analysis derived linear combinations of the five principal components of the antecedent seasonal (autumn) temperatures to distinguish between specific terciles of the predictand season (winter). Despite encouraging results for the dependent period, forecast skill for the independent test period achieved no significant score (-0.04). Unfortunately, both of these forms of analysis suffer imposed spatial limitations which restrict the scope of our investigation. Canonical correlation analysis is capable of relating the total spatial variance of fall temperatures to that of the winter temperatures for the entire United States. In this study, the technique was used to isolate seasonal patterns in winter temperature data that are correlated in time with fall temperature patterns for the same region. Summation of the first 20 canonical variate pairs suggests that autumn and winter temperatures over the continental United States are not closely related to one another

Identification and Analysis of Climatic Fields through Dot-Density Shading

Gridded matrices of climatic data can be mapped by computer with a variety of symbolization methods, all of which have some shortcomings. A new mapping procedure, dot-density shading, is herein proposed as an alternative mapping form. Dot-density shading produces continuous-appearing dot patterns whose density is proportional to the data. Significant algorithms are those for computing dot numerosity and quasi-random dot placement. A number of application including data error detection and anomaly recognition are discussed

Spatial and Temporal Variations in Long-Term Normal Percent Possible Solar Radiation Levels in the United States

The purpose of this study was to analyze the time and space variations in long-term monthly-averaged daily percent possible solar radiation levels in the United States. Both principal components analysis and harmonic analysis were used to identify the influences of various synoptic-scale climatological phenomena on solar radiation receipt. Generally, an annual cycle was found with maximum percent possible radiation levels occurring in July. In many regions the temporal variance structure deviated from this general annual cycle. The results, which are useful in both theoretical and practical studies, lead to a better understanding of the climatology of solar radiation in the United States