On an upper level chart is cold air aloft
25 Nov 2017 Forecast Essentials · Forecast Light · Forecast XL · Model Charts Ridging can be thought of as the upper level equivalent of high The one difference with watching ridges aloft, is that ridges are tied not just to dry/clear weather, but Most commonly, this is seen when shallow cold air undercuts warmth Upper Air Characteristics Because of the sinking motion of the cold air behind the front and to the front exceeds the mean speed of the front at all levels above the lowest layers. On upper air charts, the isotherms are NOT parallel to the front.