A steep pressure gradient can be signified on a surface map by closely space isobars. The more tightly packed the isobars the windier it will be. Also isobars close together indicates a low pressure system as apposed to widely spaced isobars indicated a high pressure system. Which brings up the interesting point of when a low and high pressure system meet they form what is known as a front. This is when cold dense air forces warm some times moist air aloft causing clouds and different types of weather patterns to emerge. A more specific frontal type is an occluded front which forms primary when a cold front catches up to and over takes a warm farm front. If the air mass is colder the cool air it is catching it is known as a cold type occlusion. When the front that is just cool catches a much colder front it is known as a warm type occlusion. Either way the layers always go from top to bottom warm air, cool air, and cold air, because the colder denser air will always force out the air that is warmer than it. The last word on occlusions is that they are dying fronts, an occlusion always indicates a front is in its final stages of existences.