Shelf cloud pennsylvania series#

Rain-cooled air generated from a single thunderstorm and acts like a small front surging outward from under the A gust front is the leading edge, at ground level, of the

Shelf cloud pennsylvania series#

Multi-cell storms form in series when a single thunderstorm generates a gust front and the gustįront triggers a new thunderstorm updraft (Figure 7).

When these storms grow above the freezing level, they become capable of producing lightning and thunder. They usually occur on summer afternoons resulting from daytime heating. Single cell air mass thunderstorms grow, produce rain with some gusty winds, lightning, and thunder,Īnd die within about an hour (figure 6). Source: NOAA Southern Regional Headquarters Thunderstorm Types This is known as theĭissipating stage of the thunderstorm life cycle.įigure 5. 'dissipate.' Rainfall begins to taper off and eventually the storm will end. Is no longer present to sustain the cloud with warm, moist air, the storm begins to fall apart or Once the downdraft dominates much of the storm cloud, and the updraft Once the storm has a downdraft, it is considered a mature thunderstorm and rainfall occurs at the heaviest rates.ĭowndrafts may also have very powerful winds. Heavier than warm air in the updraft and the surrounding atmosphere so it sinks down towards the surface with It is called a downdraft because a) air is being dragged downward from theįalling precipitation, and b) the falling air is cooler and more dense than the surrounding air. Where rain falls is called the downdraft. Up the precipitation particles, these fall to the surface most commonly in the form of rain. Surface has enough energy stored in it, the updraft can grow to be very strong and the cloud can grow up to 60,000įeet tall (as tall as 41 Empire State Buildings stacked on top of one another)! Once the updraft can no longer hold

The updraft pulls in more warm, moist air, helping the cloud grow taller. As this heat is generated, theĬloud grows stronger and larger and pulls air from the bottom of the cloud to the top of the cloud creating an Generated from the conversion of water vapor into water drops that form the cloud. As warm air continues to rise and condense in the cloud, heat is Thunderstorms go through a life cycle of growth, beginning as a cumulus cloud, growing from cumulusĬongestus to cumulonimbus clouds (figure 5). Thunderstorm clouds are easily distinguishable from other types of clouds because of their tall vertical dimension,Īnd in their later stages, the presence of an anvil, where the top of the cloud extends horizontally away from the 50 knots (57.5 mph) or greater wind gusts.A thunderstorm is considered severe if one or more of the following criteria are met: The more heat and moisture present in the atmosphere, the greater the chance of a thunderstormīecoming severe. In this diagram they show temperature of theĪir, and the direction and speed the wind is coming from. The black circles with black lines extendingįrom with hatch marks are examples of surface weather observations. “Cb, Cs, Ac, and Ci” denote specific types of clouds. This diagram is a three-dimensional example of how a coldĪirmass advances - lifting the warm and moist, less dense airmass over it - resulting in thunderstorms.

Vapor condenses to form clouds and rainfall.įigure 4. Mass is lifted over the mountain, and as it is lifted, the airmass cools, the water