An abnormal amount of tropical moisture is streaming up the East Coast today at the same time a cold front is arriving from the west. The collision between the front and the moisture is resulting in a rainy Monday. Almost half an inch of rain has already fallen and up to an inch more is possible before evening arrives. Some of that rainfall could be intense if thunderstorms develop. Thanks to the tropical origin of this air mass today's high will be near 80 degrees.
Today's soaking rain comes not a moment too soon as drought conditions have been worsening throughout the northeast. In Central Park, September's rainfall is more than an inch below normal, and this year's rainfall is about 7.5 inches less than average.
The cold front helping out with the rain is weakening as it approaches so we'll see a slow fade to the rain overnight with at least a chance of showers hanging on until tomorrow morning. Dry air will be here by Tuesday afternoon and, thanks to the jet stream staying way to our north, it will warm up to the mid 80s, about ten degrees warmer than normal for mid-September.
Sunny, warm and dry is the story as summer transitions into fall. With high pressure in place on the ground and ridging upper level flow our afternoon highs should be in the low to mid 80s all week long. The next chance of rain and cooler weather will be this weekend when a cold front is expected to arrive from Canada.