CSC DUATS Constant Pressure Charts show Icing Potential The Constant Pressure Charts are located under the Weather dropdown menu (see above) and are provided for: • 850 Millibar (~ 5,000') • 700 Millibar (~10,000') • 500 Millibar (~FL 180) • 300 Millibar (~FL 300) • 200 Millibar (~FL 390) Constant Pressure Chart Features The constant pressure charts show at each constant pressure level: • Temperature bands • Wind speeds • Wind Direction • Dew Point Depression • Constant pressure altitude contours The constant pressure chart shows the temperature color coded for the area at that level and has wind barbs to show location of the wind measurement, direction and speed. Next to the wind barbs is a number, which is the Dew Point Depression (DPD) value or Dew Point Spread and an indicator ( ●, o, or an X) which will help visualize the high icing potential areas. The DPD number is derived by subtracting the dew point temperature from the actual temperature. The value of the Dew Point Depression indicates the icing potential. The lower the value, the higher the icing potential. Refer to the table located in the lower left corner of the chart (see below). This value must be used in conjunction with the temperature at that altitude to determine if there is an icing potential. Note: If temperature is below -40, the icing potential is low regardless of DPD value. The charts also have altitude lines to show the altitude for the constant pressure. These charts are generated twice a day at approximately 0140Z and 1340Z.