Monday, August 11, 2014

Does This "Cooler" Summer Mean A "Cooler" Fall?

In my last post, several drivers of this summer pattern were described in detail. Some of these carried over from the winter while the building somewhat weak El Nino (though not officially) has been a more recent factor. Some of these will no doubt carry over into the fall.

Rainfall since June 13th (last 60 days as of this update) is running 8-12" above average across a few counties. More than 90% of northern Ohio is running 1-2" above average rainfall.

Let recap: Where does this summer rank through August 2nd?  24th "coolest" in the last 60 years.  We're only talking a few tenth of a degree from year-to-year in some instances.

In those summer that were "cooler" than 2014, the September 1st through October 31st period in Cleveland, HALF WERE SLIGHTLY ABOVE NORMAL AND HALF WERE BELOW NORMAL.

After taking into account the summer drivers (slightly warm water across the tropical Pacific--not quite El Nino--and warm northeast Pacific Ocean), along with the weighted years from Dr. Joe B and Joe D, here is the analog for September and October combined.

This shows that northern Ohio in fall, in those years that closely match with 2014, is normal to slightly above normal.

1 comment:

Scott Sabol, Meteorologist said...

Hi Shani, Its possible but open water this time of year in the arctic is fairly common. The bigger question would be if changes in arctic ice coverage in winter have a pronounced effect on the upper level wind pattern responsible for arctic air intrusions. Some studies point to this. Some scientists believe that the pattern that was present during Hurricane Sandy (inverted trough & Greenland Block) are more frequent because of the reduction of arctic ice cover. These cold snaps like last year have happened before: 1994 for example. The fact that we went 3 years without a lot of cold makes last winter seem that much worse. You can use this neat interactive ice cover tool to check the history of ice over the arctic and antarctic.