Does an August Singularity Exist in the Northern Rockies of the United States?

Peter T. Soulé Department of Geography and Planning, Appalachian State University, Boone, North Carolina

Search for other papers by Peter T. Soulé in
Current site
Google Scholar
PubMed
Close
and
Paul A. Knapp Carolina Tree-Ring Science Laboratory, Department of Geography, University of North Carolina at Greensboro, Greensboro, North Carolina

Search for other papers by Paul A. Knapp in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract

Climatic singularities offer a degree of orderliness to notable meteorological events that are typically characterized by significant temporal variability. Significant deviations from normal daily maximum temperatures that occur following the passage of a strong midlatitude cyclone in mid- to late August in the northern Rocky Mountains of the United States are recognized in the local culture as the “August Singularity.” Daily standardized maximum temperature anomalies for August–October were examined for eight climate stations in Montana and Idaho as indicators of major midlatitude storms. The data indicate that a single-day negative maximum temperature singularity exists for 13 August. Further, a 3-day singularity event exists for 24–26 August. It is concluded that the concept of an August Singularity in the northern Rockies is valid, because the high frequency of recorded negative maximum temperature anomalies suggests that there are specific time intervals during late summer that are more likely to experience a major midlatitude storm. The principal benefit to society for the August Singularity is that the reduced temperatures help in the efforts to control wildfires that are common this time of year in the northern Rockies.

Corresponding author address: Peter T. Soulé, Department of Geography and Planning, Appalachian State University, Boone, NC 28608. Email: soulept@appstate.edu

Abstract

Climatic singularities offer a degree of orderliness to notable meteorological events that are typically characterized by significant temporal variability. Significant deviations from normal daily maximum temperatures that occur following the passage of a strong midlatitude cyclone in mid- to late August in the northern Rocky Mountains of the United States are recognized in the local culture as the “August Singularity.” Daily standardized maximum temperature anomalies for August–October were examined for eight climate stations in Montana and Idaho as indicators of major midlatitude storms. The data indicate that a single-day negative maximum temperature singularity exists for 13 August. Further, a 3-day singularity event exists for 24–26 August. It is concluded that the concept of an August Singularity in the northern Rockies is valid, because the high frequency of recorded negative maximum temperature anomalies suggests that there are specific time intervals during late summer that are more likely to experience a major midlatitude storm. The principal benefit to society for the August Singularity is that the reduced temperatures help in the efforts to control wildfires that are common this time of year in the northern Rockies.

Corresponding author address: Peter T. Soulé, Department of Geography and Planning, Appalachian State University, Boone, NC 28608. Email: soulept@appstate.edu

Save
  • Brier, G. W., 1954: A note on singularities. Bull. Amer. Meteor. Soc., 35 , 378379.

  • Garfin, G., T. Wordell, T. Brown, R. Ochoa, and B. Morehouse, 2003: National seasonal assessment workshop, final report. Climate Assessment Project for the Southwest (CLIMAS), The University of Arizona, 24 pp.

  • Glickman, T. S., 2000: Glossary of Meteorology. 2nd ed. American Meteorological Society, 855 pp.

  • Godfrey, C. M., D. S. Wilks, and D. M. Schultz, 2002: Is the January thaw a statistical phantom? Bull. Amer. Meteor. Soc., 83 , 5362.

  • Guttman, N. B., 1991: January singularities in the Northeast from a statistical viewpoint. J. Appl. Meteor., 30 , 358367.

  • Hayden, B. P., 1976: January-thaw singularity and wave climates along the eastern coast of the USA. Nature, 263 , 491492.

  • Kalnicky, R. A., 1987: Seasons, singularities, and climatic changes over the midlatitudes of the Northern Hemisphere during 1899–1969. J. Appl. Meteor., 26 , 14961510.

    • Search Google Scholar
    • Export Citation
  • Knapp, P. A., and P. T. Soulé, 2007: Trends in midlatitude cyclone frequency and occurrence during fire season in the northern Rockies: 1900–2004. Geophys. Res. Lett., 34 .L2070, doi:10.1029/2007GL031216.

    • Search Google Scholar
    • Export Citation
  • LaBoe, B., 2000: August 20th lives in infamy. The Missoulian, 20 August. [Available online at http://www.missoulian.com/articles/2000/08/20/export45330.txt.].

    • Search Google Scholar
    • Export Citation
  • Lanzante, J. R., 1983: Some singularities and irregularities in the seasonal progression of the 700-mb height field. J. Appl. Meteor., 22 , 967981.

    • Search Google Scholar
    • Export Citation
  • Lanzante, J. R., and R. P. Harnack, 1982: The January thaw at New Brunswick, NJ. Mon. Wea. Rev., 110 , 792799.

  • McGrew Jr, J. C., and C. B. Monroe, 2000: An Introduction to Statistical Problem Solving in Geography. McGraw-Hill, 254 pp.

  • National Climatic Data Center, 2004: Summary of the Day (1867–2004). Earth Info, Inc., NCDC, CD-ROM.

  • National Oceanic and Atmospheric Administration, cited. 2007: NOAA Central Library U.S. Daily Weather Maps Project. [Available online at http://docs.lib.noaa.gov/rescue/dwm/data_rescue_daily_weather_maps.html.].

  • Newman, E., 1965: Statistical investigation of anomalies in the winter temperature record of Boston, Massachusetts. J. Appl. Meteor., 4 , 706713.

    • Search Google Scholar
    • Export Citation
  • Talman, C. F., 1919: Literature concerning supposed recurrent irregularities in the annual march of temperature. Mon. Wea. Rev., 47 , 555565.

    • Search Google Scholar
    • Export Citation
  • Wolff, K., 2000: The fire of 1910. Seeley Swan Pathfinder. August 17, 2000. [Available online at http://www.seeleylake.com/pfnews/2000news/aug00/forestclosed.html.].

    • Search Google Scholar
    • Export Citation
  • Zimmerman, G. T., and D. L. Bunnell, 1998: Wildland and prescribed fire management policy. Implementation Procedures Reference Guide, National Interagency Fire Center, Boise, ID, 92 pp.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 1944 673 35
PDF Downloads 1364 256 11