Decoding Guide

Representation Line	Type of Front	Definition
	Cold Front	Transition zone where a cold air mass is replacing a warmer air mass.
	Warm Front	Transition zone where a warm air mass is replacing a cold air mass
	Stationary Front	When a warm or cold front stops moving, it becomes a stationary front
	Occluded Front	When a cold front catches up to a warm front.
	Instability (Squall) Line	Squall line storms consist of a line of storms with a continuous, well developed gust front at the leading edge of the line.
	Trough	When pressure height contours bend strongly to the south. Strong troughs are typically preceded by stormy weather and colder air at the surface.
	Ridge	When pressure height contours bend strongly to the north. Strong ridges are accompanied by warm and dry weather conditions at the surface.

A three digit frontal code is found along the side of the analyzed front. The first digit represents the type of front, the second the frontal intensity, and the third the frontal character. The three digits are preceded or followed by a bracket, [ ].

First Digit-Type of Front	Second Digit - Frontal Intensity	Third Digit - Frontal Character
0 : Quasi-stationary 1: Quasi-stationary front above the surface 2: Warm front at the surface 3: Warm front above the surface 4: Cold front at the surface 5: Cold front above the surface 6: Occluded front 7: Instability Line 8: Intertropical front 9: Converge Line	0: Not specified 1: Weak and Decreasing 2: Weak and little change 3: Weak and increasing 4: Moderate and decreasing 5: Moderate and little change 6: Moderate and increasing 7: Strong and decreasing 8: Strong and little change 9: Strong and increasing	0: Not specified 1: Frontal activity area decreasing 2: Frontal activity area show little change 3: Frontal activity area increasing 4: Intertropical 5: Forming or existence expected 6: Quasi-stationary 7: with waves 8: Diffuse 9: Position doubtful