Tail-end of a Cold Front

              A cold front is defined as the leading edge of a cooler mass of air, replacing (at ground level) a warmer mass of air, which lies within a fairly sharp surface trough of low pressure. It forms in the wake of an extratropical cyclone, at the leading edge of its cold air advection pattern, which is also known as the cyclone's dry conveyor belt circulation. Temperature changes across the boundary can be as much as 50F (30C). When enough moisture is present, rain can occur along the boundary. If there is significant instability along the boundary, a narrow line of thunderstorms can form along the frontal zone. If instability is less, a broad shield of rain can move in behind the front, which increases the temperature difference across the boundary. They are stronger in the fall and spring transition seasons, and weakest during the summer. When they catch up with the preceding warm front, the portion of the boundary which does so is then known as an occluded front.

          The cooler and denser air wedges under the less-dense warmer air, lifting it. This upward motion causes lowered pressure along the cold front and can cause the formation of a narrow line of showers and thunderstorms when enough moisture is present. On weather maps, the surface position of the cold front is marked with the symbol of a blue line of triangles/spikes (pips) pointing in the direction of travel. A cold front's location is at the leading edge of the temperature drop off, which in an isotherm analysis would show up as the leading edge of the isotherm gradient, and it normally lies within a sharp surface trough. Cold fronts move faster than warm fronts and can produce sharper changes in weather. Since cold air is denser than warm air, it rapidly replaces the warm air preceding the boundary.

In the northern hemisphere, a cold front usually causes a shift of wind from southwest to northwest clockwise, also known as veering, and in the southern hemisphere a shift from northeast to southwest, in a clockwise manner

Front boundary of 2 air masses, found in mid-latitudes is the later portion of an advancing or leading edge of a steep cold wedge of air characterized by cumulus and cumulonimbus clouds with frequent precipitation in the form of heavy shower

A cold front is the front of a cold air mass, or basically a giant bubble of relatively cold and dry air. A front in general is an area of disturbed weather at the front of an air mass (and, by definition, the back of the air mass it is pushing out of the area

·         The tail end of a front is the back edge of that frontal boundary, not the back of the air mass itself.

Manila, Philippines

A tail-end of a cold front affecting Northern and Central Luzon is causing rain in parts of the country, including Metro Manila, the Philippine Atmospheric Geophysical and Astronomical Services Administration said Monday.

But the rain is expected to ease  tonight or Tuesday morning, said Pagasa weather forecaster Jori Loiz.

A cold front is formed from the replacement of cold air mass with warmer air mass, said Loiz.

In its 5 a.m. bulletin, Pagasa said Luzon and Mindanao would experience mostly cloudy skies with scattered rainshowers and thunderstorms becoming cloudy with widespread rains over Northern Luzon and the eastern section of Southern Luzon which may trigger flashfloods and landslides, it said.

The rest of the country will be partly cloudy to cloudy with isolated rainshowers or thunderstorms.

Moderate to strong winds blowing from the northeast and east will prevail over Luzon and coming from the east over the rest of the country. The coastal waters throughout the archipelago will be moderate to rough, the state weather bureau said.