It’s hard to believe that September starts on Tuesday. Fall is 24 days away and before you know it the leaves on the trees will be changing colors and the fall harvest will soon be starting. Football is well underway across Iowa with high school games and the college and pro teams starting soon. Before all of that it does appear that summer will go out with some summer like temperatures before a change in the pattern takes place and cooler weather moves in later in the month.
But first let’s take a look at the first part of September. It does appear that an upper level ridge will dominate the southern US and that will allow for warm summer like air to make its way back into Iowa. Many forecast models support this scenario and the CPC forecast for the next 6 to 10 days supports this.
Iowa will be in the NW edges of the upper level ridge for the first 6 to 10 days of September with a 40% to 60% chance of seeing above normal temperatures. That will equate to temperatures well into the 80’s and possibly some 90’s during this time.
The overall weather pattern could be active as well with a 40% chance of seeing above normal precipitation in Iowa.
As we enter the middle portions of the month however there are signs that the ridge over the Southern US will start to break down and allow a trough of low pressure to move in from the west. This will allow cooler weather to arrive after September 10th. The CPC forecast shows this cool down in its 8 to 14 day forecast.
The NCEP forecast is much more bullish on bringing in cooler weather during that September 10th time frame.
Precipitation looks to remain above normal as well as we enter mid-September.
As we enter the last half of September it appears right now that temperatures will remain generally below normal towards the end of the month with some modification to normal likely. Precipitation right now for the last half of the month could stay above normal especially in the SW portions of Iowa. We’ll be monitoring the weather over the coming weeks to make any adjustments to the long term forecast but right now that is what I’m seeing.
As always be weather aware and enjoy the weather because it’s the only weather we got.