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Graphical Weather Products. Chapter 9, Section D. Surface Analysis Chart. Surface Analysis chart is a good source for general information over a large area. Shows position of fronts, temperature, dewpoint, wind at valid time of the chart
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Graphical Weather Products Chapter 9, Section D
Surface Analysis Chart • Surface Analysis chart is a good source for general information over a large area. Shows position of fronts, temperature, dewpoint, wind at valid time of the chart • When solid lines, called isobars, are close together the pressure gradient is greater and the winds are stronger • A dashed line indicates a weak pressure gradient
Weather Depiction Chart • Information on the chart is derived from the METAR reports • Provides an overview of favorable and adverse weather • Prepared every three hours • A bracket symbol ] to the right of a station circle means it is an automated location
RADAR Summary Chart • Only chart which shows lines and cell of thunderstorms • You can determine the tops and bases of the echoes, the intensity of the precipitation and direction of movement • Most effective when used in combination with other charts, reports, and forecasts
Terms • Isopleths - used on precipitable water panel and are lines of equal value • Isohumes - used on average relative humidity panel and are lines of equal relative humidity • Isotherms - are lines of equal temperature • Isotachs - are lines of equal wind velocity on Constant Pressure Analysis Charts
Graphic Forecasts • Low-level Significant Weather Prognostic Chart is valid up to 400 millibars of pressure or about 24,000 feet • Issued four time a day with a valid time printed on the lower margin of each panel • Shows areas of IFR, MVFR, VFR and moderate or greater turbulence