Transition to Fall is on the way

The transition from Summer to Fall is on the way and will be in full swing by next week.  

You can thank the develops in the Pacific the last several weeks for what will be a very pleasant yet cool period of weather coming by next Wednesday night.  You see, when discussing pattern changes and recognition of those changes, you have to look at more than just your back yard, which right now is probablly rather wet, but also what's happening in the back yards in Alaska, Russia, China, and even in Italy.  What happens in another part of the world does matter and influences the weather in your backyard in Monmouth County.  

So what's happening in the Pacific you ask?  Plenty!  For one, La Nina is on the way back and is showing similar characteristics to last year's east-based La Nina.  An east-based La Nina is where the coldest waters are focused more towards South America rather than the date line (180 degrees Longitude).  Why is that important you ask?  

Trough dynamics!

Okay, follow me here and I promise I won't throw out any equations.  You see, the relatively warmer waters around the date line compared to the waters off South America is occurring due to the development of low and mid level winds and pressure systems.  Basically, this set up that is occurring leads to strong lifting over the western and central Pacific, which means tropical convection or thunderstorms.  These thunderstorms help to enhance lifting further north towards the Aluetian Islands in Alaska, which leads to a deeper trough between the Aluetian Islands and the western Gulf of Alaska.  This is called a negative Eastern Pacific Oscillation(EPO), which leads to a ridge in the western United States and a trough in the eastern United States!  The positive EPO pattern puts an upper low in the Gulf of Alaska or on the west coast of Canada and is a ridge over the eastern two-thirds of the United States.  

So we know that the Pacific supports a trough in the Eastern United States over the next 15 days.  This trough is going to take some time to develop and as such, we've been dealing with some very wet conditions as troughs interacting with various tropical low pressure systems have been producing a great deal of rainfall over central New Jersey.  However, we will finally get to the pay off by the middle and later parts of next week when a Polar high pressure system drops south from central Canada right into the Ohio River Valley and eventually right over New Jersey.  This high pressure system will bring much cooler weather conditions with lows in the 50's and highs in the upper 60's to lower 70's by Thursday!  

So Fall weather conditions are on the way, and you can thank a thunderstorm complex in the middle of the Pacific for those great weather conditions next weekend.