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A cold front is the leading edge of a cooler mass of air at ground level that replaces a warmer mass of air and lies within a pronounced surface trough of low pressure.It often forms behind an extratropical cyclone (to the west in the Northern Hemisphere, to the east in the Southern), at the leading edge of its cold air advection pattern—known as the cyclone's dry "conveyor belt" flow.
In a warm occlusion, the cold air mass overtaking the warm front is warmer than the cold air mass receding from the warm front and rides over the colder air while lifting the warm air. [ 2 ] A wide variety of weather can be found along an occluded front, with thunderstorms possible, but usually their passage is also associated with a drying of ...
Outflow boundary on radar with radial velocity and frontal boundary drawn in.. An outflow boundary, also known as a gust front, is a storm-scale or mesoscale boundary separating thunderstorm-cooled air from the surrounding air; similar in effect to a cold front, with passage marked by a wind shift and usually a drop in temperature and a related pressure jump.
As supercells and multi-cell thunderstorms dissipate due to a weak shear force or poor lifting mechanisms, (e.g. considerable terrain or lack of daytime heating) the gust front associated with them may outrun the squall line itself and the synoptic scale area of low pressure may then infill, leading to a weakening of the cold front; essentially ...
A squall line is an elongated line of severe thunderstorms that can form along and/or ahead of a cold front. [11] [12] In the early 20th century, the term was used as a synonym for cold front. [13] The squall line contains heavy precipitation, hail, frequent lightning, strong straight-line winds, and possibly tornadoes and waterspouts. [14]
The threat for severe thunderstorms will shift eastward and northward Tuesday, with a large swath of the central U.S. from Minnesota and Wiscons Severe thunderstorms to target the Plains, powerful ...
The cold front could extend for as much as 1,000 miles along the highway while closing off travel and shutting down power on that corridor for a prolonged period, AccuWeather said. ... of 6:30 p.m ...
Once the flow of warm and moist air is cut off from thunderstorms and their associated tornadoes, normally by the thunderstorm's own rain-cooled outflow boundary, the storms begin to dissipate. Rear inflow jets behind squall lines act to erode the broad rain shield behind the squall line, and accelerate its forward motion.