Upper level troughs will define September weather. As low pressure systems dig south across the the plains and into the mid-west we will see the return of cooler air into the Miami Valley.
The first of several cold fronts this month will move through the region on Friday.
This will result in below-normal temperatures heading into next week.
The Climate Prediction Center released the September outlook on May. Right now the Miami Valley is on the edge of an area with a greater chance for above normal temperatures.
Rainfall looks to be more abundant across the Ozarks and into eastern Oklahoma.
This is a pattern very similar to a La Nina winter pattern. The Climate Prediction Center issued a La Nina Watch a couple of weeks ago with a 60% chance of development.
Temperatures swings are more likely during La Nina. We will begin to see that during September.
The normal high drops 11 degrees during the first fall month.
We start the month with a normal high of 81 degrees and end the month with a normal high of 70 degrees. The average high across the month is 75.9 degrees. The average low is 54.9 degrees. The normal amount of rainfall is 3.30 inches.