MODIFICATION OF THE FJORTOFT GRAPHICAL PROGNOSIS METHOD.

This paper presents a relatively simple method for producing a 24-hour prognostic 500-mb chart by graphical means. It modifies the Fjortoft graphical method by incorporating a technique to include the intensification and weakening of systems. That is, it uses factors which allow intensification of p...

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Bibliographic Details
Main Authors: Clark, Stanley Davis, Sr., Langemo, James Carroll
Other Authors: NAVAL POSTGRADUATE SCHOOL MONTEREY CA
Format: Text
Language:English
Published: 1966
Subjects:
Meteorology
Cartography and Aerial Photography
*WEATHER FORECASTING)
(*METEOROLOGICAL CHARTS
ATMOSPHERIC MOTION
CYCLONES
ANTICYCLONES
ATMOSPHERE MODELS
INTENSITY
ALTITUDE
BAROMETRIC PRESSURE
VORTICES
WIND
NUMERICAL ANALYSIS
NORTH AMERICA
PACIFIC OCEAN
NORTHERN HEMISPHERE
ATLANTIC OCEAN
EQUATIONS
GRAPHICS
DIURNAL VARIATIONS
NORTH ATLANTIC
NORTH PACIFIC OCEAN
Pacific
North Atlantic
Online Access:http://www.dtic.mil/docs/citations/AD0803354
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=AD0803354
Description
Summary:This paper presents a relatively simple method for producing a 24-hour prognostic 500-mb chart by graphical means. It modifies the Fjortoft graphical method by incorporating a technique to include the intensification and weakening of systems. That is, it uses factors which allow intensification of poleward-moving cyclones and weakening of equatorward-moving cyclones and the converse for anti-cyclones. The theoretical development of the so-called 'geostrophic model' used, the research procedure, and a number of illustrative charts are all discussed and a table of chart verification scores is presented to assist in the reader's evaluation of the method. It is concluded that this method does provide a simple prognostic procedure which includes some intensity change for systems. The results showed an average 24.9% improvement over persistence for the charts analyzed using a height-gradient verification scheme. Appendix 1 outlines the specific procedure for utilizing the method on a practical basis and is included as such for the convenience of potential users. (Author)

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