Back in college, I remember one of my professors telling us that our atmosphere is a fluid.  Like an efficient piece of plumbing, the atmosphere flows with currents of moving wind, water vapor and particles.  If the digestive track of the atmosphere is kosher then weather systems move very efficiently from west to east.  Every so often, though, atmospheric indigestion sets in and we have a blockage in the flow.  In this type of blocking pattern, weather systems move very little from west to east and the same areas may receive either a sunny or a gloomy weather pattern for weeks on end.

This type of weather situation has been occurring across the nation for the past few weeks.  The Midwest has been relatively sunny and dry.  In fact, many areas in the Upper Midwest have had one of the driest starts to a September on record!  Also, it has been unusually warm by September standards.  Take the Twin Cities for example, today may be their 9th day this month with temperatures reaching 80+ degrees.

On the flip side to this blocking pattern, the South has been experiencing drenching rains mixed within a soupy airmass.  Rainfall amounts have been high, especially in Arkansas, where Doppler radar estimates print out over 10" of rain!

Rainy weather will slowly taper down through the weekend in the South, while the Midwest will get a shot at rain.  The flow looks to open back up next week.  Weather systems will be more progressive, helping to clear (and clean) up the pipes so to speak.  The air could use a good cleaning in the Midwest.  Take a look at this picture below taken from the GOES-11 satellite.  Areas of smoke from fires in southern British Columbia can been seen in North Dakota, Minnesota, Iowa and Illinois.

Kristin Clark

Meteorologist, WeatherNation, LLC