Yes, the Pattern Has Shifted - Lunch Update

During lunch I had the time to look at the weather for the next 24 hours more closely. Based on observations, I will make a couple adjustments. 

1) A leading line of thunderstorms will be well ahead of the actual cold front. This will impact NW PA starting late this afternoon and evening. This line will move east during the first part of the night. If it holds together, we may get some rain after 10 pm. It may fall apart too as the support for it shifts NE. 

2) A trough will precede the front east of the mountains, resulting in a lack of convergence along the front itself for Thu meaning not a lot of reason for initiating showers or thunderstorms. Thu is now looking much drier due to this. 

3) A dewpoint drop will occur later tomorrow afternoon/evening with the real front passing through. The drop will feel great for the overnight and early Fri, but the humidity will return by later Fri. 

A few weeks ago, I said that the excessive rains would not end until the pattern shifted. And it has. The ridge has essentially for all practical purposes, shifted west into our region. The excessive rain area has taken up residence in the Upper Mississippi valley and great lakes, and the trough position has shifted into the Pacific NW. I am speaking in general terms here. And this is more of a seasonal adjustment, not a wholesale shift in all things. Some would argue against that, but I am talking in terms of general weather impacts for the regular every day person like you and I. It has shifted. 

This shift may lead to a dry, warm and very humid September, esp the first half of the month. The ridge will not disappear easily, it is well supported by the warm water off the Mid-Atlantic coast. Because of this I seriously doubt the cold front will move through tomorrow (Thu) around noon. I think it slows to a crawl and does not move through until tomorrow evening at the earliest. This should produce some showers and thunderstorms. They will be scattered, and not be widespread like we've been used too. But any storm could produce very heavy rain. 

The front should stall just south of the PA border. This then puts us in a cooler NE wind flow. This will cut off the hot weather, but its not cool enough to eliminate the humidity. It will stay humid, perhaps a little less than what we have, but do not expect any refreshingly cool, crisp nights. 

A stalled boundary will produce showers and storms. Most of which will stay just to our south, but will be close enough that we will have chance Fri -  Labor Day. The best chance looks to be Sun as a new, but weakening front comes toward us from the west. The best day of the coming weekend looks to be Monday: decent sunshine, with a chance for a shower/storm. 

Again, the ridge will dominate through most of next week giving us warm to very warm and humid conditions. There will be chances of rain, but nothing too heavy. 

Enjoy. Stay cool.