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500 hPa geopotential height and 850 hPa temperature
500 hPa geopotential height and 850 hPa temperature
Control forecast
850 hPa temperature (C)
500 hPa geopotential (dm)
850 hPa temperature (C)
500 hPa geopotential (dm)
850 hPa temperature (C)
500 hPa geopotential (dm)
850 hPa temperature (C)
500 hPa geopotential (dm)
850 hPa temperature (C)
500 hPa geopotential (dm)
850 hPa temperature (C)
500 hPa geopotential (dm)
850 hPa temperature (C)
500 hPa geopotential (dm)
850 hPa temperature (C)
500 hPa geopotential (dm)
850 hPa temperature (C)
500 hPa geopotential (dm)
Mon 30 Dec 2024 00 UTC (T+0)
These charts are the most recent from the ECMWF Control Forecast (ex-HRES)
Select desired base time and valid time using the drop down menu. Base times cover the past five days. The drop-down menu is also used to select different map areas. Date/times can also be selected using the slider underneath the chart, or the chart can be animated using the play/pause symbols at the bottom left.
500 hPa geopotential heights contours (in dam) at 4 dam intervals. These show approximately how far one has to go up in the atmosphere before the pressure falls to 500 hPa. On average this level is around 5.5 km above sea level. It is often referred to as a steering level, because the underlying weather systems roughly move in the same direction as the winds at the 500 hPa level.
In the northern hemisphere the air rotates anti-clockwise around low contour centres and clockwise around the high contour centres. In the southern hemisphere the air rotates clockwise around low contour centres and anti-clockwise around the high contour centres.
The contours effectively show the main tropospheric waves that "control" our weather - low heights indicate troughs and cyclones in the middle troposphere whilst high heights indicate ridges and anticyclones. Wind speeds are roughly proportional to the distance between contours, so closely packed contours mean strong winds.
Air temperatures (in ºC) at 850 hPa (about 1.5 km above sea level) are shown using colour shading with intervals of 4ºC – click on the middle icon to the bottom right for the scale.
The 850 hPa level is usually just above the boundary layer and at this level the day-night variation in temperature is generally negligible. Therefore air temperature at 850 hPa can be used to distinguish between warm and cold air masses or indicate frontal zones (i.e. areas of large temperature gradient, where the isotherms are more closely packed together). Sometimes the temperature at 850 hPa can be used to assess roughly the maximum daytime temperature at sea level by adding 10ºC to 15ºC (interpolate for higher ground). However, there are situations when this method does not apply, particularly in winter.
A left click on any chart location produces a ten-day ENS meteogram for that place.