Wall Cloud

A localized, persistent, often abrupt lowering from a rain-free base. Wall clouds can range from a fraction of a mile up to nearly five miles in diameter, and normally are found on the south or southwest (inflow) side of the thunderstorm in the Northern Hemisphere.  When seen from within several miles, many wall clouds exhibit [...]

By | December 1st, 2016|, , |0 Comments

Weather Prediction Center

The Weather Prediction Center (WPC), located in College Park, Maryland, is one of nine service centers under the umbrella of the National Centers for Environmental Prediction (NCEP), a part of the National Weather Service (NWS), which in turn is part of the National Oceanic and Atmospheric Administration (NOAA) of the U.S. government. Until March 5, [...]

By | January 28th, 2016|, , |0 Comments


The horizontal motion of the air past a given point. Winds begin with differences in air pressures. Pressure that's higher at one place than another sets up a force pushing from the high toward the low pressure. The greater the difference in pressures, the stronger the force.

By | December 1st, 2016|, , |0 Comments

Wind Shear

The rate at which wind velocity changes from point to point in a given direction. May be speed shear, where speed changes between the two points, but not direction; directional shear, where direction changes between the two points, but not speed; or a combination of the two.

By | January 27th, 2016|, , |0 Comments