East, West, and in Between

Let's do a little meteorology.

The upper air map (see the first map below) at 500 mb this morning (approx. 18,000 ft) shows a trough over the East Coast of the U.S. and another over the Northern Rockies. A ridge of high pressure is in between.

Large upper air systems (troughs and ridges) usually have reflections at the surface. The trough in the west is associated with a cold front and low pressure in the Rockies and High Plains. The trough along the East Coast is reflected on the surface by low pressure off Rhode Island and Connecticut with a cold front dropping south just off the coast. The surface high over Michigan this afternoon is a reflection of the upper ridge that extends from NW Canada to Lake Winnipeg then south to Louisiana. Upper troughs are associated with rising motion and upper ridges are associated with sinking motion in the atmosphere. 

With sufficient moisture available rising motion creates clouds. Looking at the station model plots on the surface map below we see cloudiness associated with western trough and the eastern trough. 

500H_9-30-17_web.jpg

Upper Air Map, 7 a.m. CDT, 9-30-2017 (Plotted using Digital Atmosphere, www.weathergraphics.com)

 Surface Map 5:00 p.m. CDT, 9-30-2017 (Plotted using Digital Atmosphere, www.weathergraphics.com)

Surface Map 5:00 p.m. CDT, 9-30-2017 (Plotted using Digital Atmosphere, www.weathergraphics.com)