Model: GFS (Global Forecast System) Global Model from the "National Centers for Environmental Prediction" (NCEP)
Update: 4 times per day, from 3:30, 09:30, 15:30 und 21:30 GMT
Greenwich Mean Time: 12:00 GMT = 13:00 BST
Parameter: Mean relative humidity between 0 and about 300 m above the ground level
Description: This chart shows the mean relative humidity for the atmospheric layer between 0 and 300m. Although this map is less important than RH-charts (like 925 hPa or 700 hPa) it still gives some useful hints on very shallow humidity inversions and thus temperature inversions.