This is a set of contour plots using data from the NAM model. The output fields are consistent with other models so the models can be compared. This model gives forecast information out to 48 hours and plots are sorted 48 hour 4 panel plots where each plot has a panel for the 12, 24, 36 and 48 hour forecast and individual forecast times from initialization to 60 hours in 6 hour increments. These plots are updated once every 12 hours at roughly 11:15 EST.
0 - 3000m Helicity
Helicity is used to indicate where rotation/shear is high enough to allow thunderstorms to organize into severe or supercell storms. In the lack of helicity, storms develop vertically and the precipitation will snuff out the updraft killing the thunderstorm. Severe storms need helicity to maintain an organized structure allowing hte storm to develop to severe limits. A value of 400-500 is often needed to produce severe storms. Often this is used in conjunction with CAPE to determine severe storm location.