Weather Graphic Products

Surface Analysis Chart

• Surface Analysis - Shows fronts, data such as temperature, dewpoint, & wind

Solid lines, called isobars, close together, indicate pressure gradient is greater and winds are stronger

A dashed line indicates a weaker pressure gradient

Weather Depiction Chart

• Information from the METAR reports• An overview of favorable and adverse

weather• Prepared every three hours

• This bracket symbol ] to the right of a station circle means it is an automated location

RADAR-Summary Chart

• Shows lines and cell of thunderstorms• Numbers indicate the height of the tops

and bases of the echoes. The intensity of the precipitation and direction of movement is also provided.

• Use in combination with other weather charts, reports, and forecasts

Analytical Terms

• Isopleths – lines of equal value, used on precipitable water panels

• Isohumes – lines of equal humidity, used on average relative humidity panels

• Isotherms - lines of equal temperature• Isotachs - lines of equal wind velocity

on Constant Pressure Analysis Charts

Graphic Forecasts

• Low-level Significant Weather Prognostic Chart, valid up to 400 millibars of pressure, or about 24,000 feet

• Issued four time per day, valid time printed on the lower margin of each panel

• Shows areas of IFR, MVFR, VFR and moderate or greater turbulence