Thursday, September 13, 2012

Are We Done With 80 Degree Temps This Year?

It happens each year.

The first cool snap and everyone is rushing to prematurely proclaim the end of summer, an early start to fall and snow by Halloween. I see the posts on Facebook and I just shake my head. Sure, sometimes it works out this way but often times, their is still some summer warmth left in the tank in October.

Quickly, I checked the October highs over the last 30 years (since 1982) to see how often we reached 80+ degrees. It doesn't happen very often. Try only 3% of the time! Only 9 times did we reach 80+ twice in one year (Last year, 2007 and 2005 were the last instances)

What does the pattern say? It is strongly hinting at a longer surge of cooler air not only across northern Ohio but across the eastern half of the country! Take a look at the current upper level steering currents. Notice the trough (dip) in the flow.

This is NOT the pattern we saw this past summer. Remember the heat around the 4th of July? Look at where the trough was back then. Obviously no where near the eastern US and Ohio.
By the middle of August, the ridge was breaking down and the trough started to build weakly in the east cooling temperatures off allowing a series of rain producing systems to alleviate drought conditions a bit.
The strength and duration of the cooler pattern is determined by the characteristics of the trough. If the trough's amplitude and wavelength are very high, the pattern becomes more difficult to change once its established. This diagram of a sound wave works well in describing the upper level wave that governs our weather.

Check out the computer model projections for late next week. The trough is deep and very wide on just about all of them.

All of these projections tell me a few things:

1) The cool down will be sharp and long lasting (3-5 days or more)

2) 80 degree high temperatures will be very hard to come by if this pattern becomes stagnant late in the month. Remember that 3% chance statistically in October earlier

3) Even if the trough ends up not being as deep and wide as indicated above, the chances of temperatures being below normal are very high.

3) The frequency of rain producing fronts will be much higher in the the next 10 days

As always, stay tuned to the latest forecast. The specific details will be in better focus as we start next week.


Misti said...

Thanks for summarizing this for those of us who are science challenged! :)

Misti said...

Thanks for summarizing this for those of us who are science challenged!!! :)