Upper Air Charts and Analyzed Maps

500 mb Data

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500 mb Analysis

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Click here for latest 500 mb Data chart from website Click here for latest Analyzed 500 mb map from website

The map on the left is constructed from data collected at a pressure value of 500 mb (about half of sea level pressure) from the network of rawinsonde stations across the conterminous U.S. The data are plotted in an upper air station model where the forward end of the wind barb is at the upper air station site. For a description of the upper air station model, click here.

Analysis lines:


300 mb Data

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300 mb Analysis

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Click here for latest 300 mb Data chart from website Click here for latest Analyzed 300 mb map from website

Analysis lines:


Click for a sample: 850 mb map 700 mb map
Click for the latest chart from the website: 850 mb map 700 mb map


On these upper air maps, altitude at which the chosen pressure occurs is given in meters, coded to conserve space on the map. One needs to add one or more digits to decode the actual altitude from the station model.

Pressure Level
(mb)
Average Altitude
(m) *
Coded Map Digits
(xxx from station model)
Altitude
(ft.) *
850 1457 1xxx 4781
700 3012 2xxx or
3xxx
9882
500 5574 xxx0 18 289
300 9164 xxx0 30 065
* Value in Standard Atmosphere.

Upper air charts are typically drawn for "surfaces"of constant pressure, that is, assembled from data collected twice daily by rawinsondes at that particular pressure value. The routine pressure values for which upper air maps are displayed by the DataStreme Atmosphere homepage are: 850 mb, 700 mb, 500 mb, 300 mb. Additional data are collected including so-called mandatory levels from each rawinsonde measurement profile (if sufficient altitude is achieved): 1000, 925, 850, 700, 500, 400, 300, 250, 200, 150, 100, 85, 70, 50, 40, 30, 25, 20, 15, 10 mb.


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