Transcript Graphical Weather Products

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