September forecast for Mid-Missouri

It certainly has been a fantastic summer, temperature-wise that is, in Mid-Missouri. Well, that was until the middle of August. We have been 1.3 degrees below average for the summer months (June, July and August). So, what kind of weather will the first month of fall bring? Letâ??s jump into my September forecast for Mid-Missouri!

Even though September is considered the first month of fall, we do not officially begin autumn until the autumnal equinox on September 22 at 9:29 pm. Any by the looks of my long-range forecast, we likely will not start to feel the more fall-like temperatures until the middle to end of the month.

Temperatures & Precipitation

The trend of warmer-than-average temperatures looks to continue for the first two to three weeks of the month. We continue to be influenced by a weather pattern controlled by a southern dome high pressure â?? similar to the last few weeks of August. Much cooler air is stuck in the northern United States and into Canada with the northern (and cooler) branch of the jet stream. We will see a few days of cooler temperatures, but the first few weeks of the month will be dominated by temperatures in the 80s (and maybe a few days, the low 90s). As we get to the last week or so of the month cooler air should return to the area. Temperatures should be near or just below average as we end September. When the month is said and done, I think we will see that the average temperature will be above average. The average high temperature at the beginning of the month is 84 degrees and by the end of the month is much more fall-like at 73 degrees â?? this is one of those months where we really start to think â??where has summer goneâ?? as we start to feel some cooler temperatures. The Climate Prediction Center has Missouri in an â??equal chanceâ?? for above or below temperatures for the month:

September temperature outlook from the Climate Prediction Center (CPC).

Looking at rainfall, September is not known for being one of our wetter months. We receive 3.87 inches of rain through the month on average. I think we will see slightly below average rainfall, but it should not be an abnormally dry month across Mid-Missouri. The beginning of the month actually appears to have several shots of beneficial rainfall for the area. Here is the Climate Prediction Center outlook for the month below:

September precipitation outlook from the Climate Prediction Center (CPC).


Drought conditions across Missouri did not really change much during the month of August, which is certainly great news. Rainfall for the month was 2.94 inches. This was 1.42 inches below were we should be for the month of August. At this point, I do not think that the drought gets any more severe in September, even with below average rainfall expected.

Drought monitor for Missouri as of Thursday, August 28, 2014 via NOAA.

Highlights for September

*First few weeks stay on the warmer side... cooler by the end of the month.

*Rainfall will not be impressive and will likely end just below average

Looking Ahead

El Nino continues to be the wild-card in my long range forecast. Iâ??ve been talking about us moving into an El Nino
pattern for a while.. but it hasnâ??t quite happened yet. Oceans waters in the tropical Pacific have been oscillating between cooler and water temperatures. This makes my long range forecast a bit harder. I do think that we will experience weak El Nino conditions as we move into fall and eventually into the winter. A weak El Nino occurs when ocean temperatures are 0.5-1.0 degrees Celsius above average.

Observed Central Pacific Ocean temperatures and forecasted ocean temperatures through April of 2015. This shows the move toward El Nino conditions.

Another thing I will be looking at are the maps from the winter of 2009-2010. There are a lot of similarities in our current weather patterns from this year and in the 2009-2010 season. I wonâ??t give away my thoughts on the winter forecast just yet.. Iâ??m saving that for my next long range forecast!

How did I do with my August forecast?

It seemed like this was almost a year without a summer; temperatures have been well below average for June and July. However, I did think we would see a overall pattern flip in the atmosphere. I suggested that we would see hard-core heat during the middle of the monthâ?¦ and boy did we!

The timing was off a bit on the heatâ?¦ but we certainly saw some hot air across the area. We officially saw a high of 98 degrees on 25th which was our highest temperature this summer... however, many locations saw temperatures in the lower 100s across Mid-Missouri; along with that, heat indices were close to 110° in spots as well. This part of the forecast worked out well.

In terms of precipitation, I thought we would see a lack of rainfall this month due to hard-core heat and we were below average. We saw a 2.94 inches of rain when we normally see 4.36 inches. This means we only received 67% of the normal rainfall. I did think drought conditions would really start to ramp up, but that did not happen â?? which is good news. With a few timely rains, soil moisture conditions stayed about the same.

Click here for a look back on my August 2014 forecast.