AEROGRAPHER'S MATE 3 & 2 



NORTH ATLANTIC 

 I _ J 



North Atlantic weather map drawn from reporta Included in a shipping bulletin broadcast Croaaaa at the centers of lows and biobb, and along the 

 isobars and fronts shown on the map, are for the purpoae of explaining the plotting of weather maps from coded analyses message*. 



Figure 11-13. — Map showing plotted IAOFLEET analysis. 



209.291 



since they depict conditions existing along a 

 constant pressure surface. They are a valuable 

 aid in forecasting any weather conditions for 

 any locality. 



and dissemination of radiosonde observations 

 are discussed in other chapters of this train- 

 ing manual. 



A constant pressure chart is a chart show- 

 ing meteorological data at a particular stand- 

 ard level. The meteorological data for these 

 charts are obtained from radiosonde and ra- 

 winsonde observations. The standard pressure 

 levels mentioned are those levels for which 

 mandatory data are transmitted in the radio- 

 sonde code. These include the 1,000-, 850-, 

 700-, 500-, 400-, 300-, 250-, 200-, 150-, 100-, 

 70-, 50-, 30-, 20-, 10-, 7-, 6-, 3-, 2-, and 

 1-mb levels. The taking, coding, evaluating, 



From tima to time and from place to place 

 there are different pressures at a particular 

 level in the atmosphere. The constant pressure 

 charts are designed to show these differences 

 of pressure in space and time. 



Although constant pressure charts may be 

 prepared for any or all of the mandatory levels, 

 the most common charts in use are the 350-, 

 700-, 500-, 300-, 200-, and 100-mb charts. 



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