Forecasting Notes and Information
Loaded Gun Storm Chasing
website of storm chaser Mikey Gribble
Bulk Richardson Number - Multicell Storms = R > 30   Supercells = 10 < R <40
According to Weisman and Klemp storms are likely to be multicell whenever BRN > 45, and may be supercell
when BRN < 45. When BRN is < 10 with undirectional shear, storms may be supressed by the excessive
shear, although with curved hodographs this suppression is less noticeable. (McCaul Jr., Steve Lazarus, and
Fred Carr)
1. Tim Vasquez, Weather Forecasting Handbook
2. Jon Davies, various case study papers
Cloud Cover - Any areas where the isotherms cross the height contours often idicate potential areas of cloud
and precipitation development. Dewpoint depressions of 5 degrees C or less outline areas of possible clouds.
(Tim Vasquez)
On the 700mb chart, the 70% relative humidity line usually encloses areas that are likely to have cloud cover.
90% relative humidity on the 700mb chart usually means rain.
Short Waves (Doswell)
Short waves tend to move at a speed proportional to the average wind speed near the 700mb level.
- when a short wave moves into a trough the trough (long wave) tends to deepen
- short waves tend to deepen when they approach a trough and weaken when they approach a ridge