Weather help, how high is 850 mb.

Just trying to figure out how high 850mb is. I hear often "winds could get to 70 knots at 850mb" if you happen to know, then how high is 500mb and 900mb. Thanks.

850mb is 4779.2 feet or 0.905151515 miles.

500mb is 18281.2 feet or 3.462348485 miles.

900mb is 324.8 feet or 0.061515152 miles.


http://www.srh.noaa.gov/images/epz/wxcal…

The short simple answer that I think you want is; the height of 900 mb level is about 3000 ft, 850 mb is about 5000 ft., the 500 mb level is around 18,000 ft. The altitude are all above mean sea level (MSL). Please note that the 900 mb and 850 mb levels are frequently below actual ground level in mountainous regions. Mountainous areas at or above these pressure levels are artificial and based on standard atmospheric assumptions in those areas on constant pressure maps.

The height units used for constant pressure maps are normally in geopotential decameters measured by balloon soundings and aircraft. To try to obtain an exact height above MSL is difficult since all fields are in constant motion and heights can change rather quickly near strong systems so thus the approximation in height is often used when talking to most people. When talking about constant pressure fields, the heights are variable and this variance can be several hundred feet depending on your location and the relationship to the weather systems affecting the area. While you can look to see the approximate height (within about 10 feet) of the field on each of the constant pressure charts. But the information can be 2 to 14 hours old since the charts take time to compute after the balloon runs normally only two per day so the height in discussions often are just rounded off for simplicity like in your example.

The height of the 850 mb level depends on the temperature.

The height will be lower when the temperature is colder than it will be when the temperature is warmer.