Wednesday 8 a.m.
The morning video shows why sunshine should prevail across most of the Northeast right into the weekend.
On Monday, my backyard in the middle of Pennsylvania had its first significant rain in weeks, and there was a a great amount of lightning and even some hail. I was making timelapse movies using intervals of just under 1 second per shot. In the past, I have captured some lightning strikes this way (and saved the individual frames with the lightning as still images). Typically, I use an interval between 3 and 10 seconds depending the rate of cloud movement. When the cloud motion is rapid, a short interval is needed. Otherwise, the clouds would look like they are going so fast that the viewer cannot see the details. Here are couple of lightning pictures from late Monday, Sept. 3, 2013.
This bolt meanders quite a bit.
This bolt is straighter and more vertical than the other one.
While lightning strikes happen suddenly, the thunder can go on for a long time. This is because you first hear thunder coming from the part of the part of the spark that is closest to you. After this, you hear thunder that emanated from parts of the spark (or sparks) that were farther away. The curving or zig-zag shape of the lightning stroke accounts for some of the variation in sound as the thunder continues. Since it takes about 5 seconds for sound to travel 1 mile, you can count out 1accuweather, 2accuweather, 3accuweather and so on to help calculate the number seconds between the light and the boom.
After reaching the 80s today from NYC to Boston, it might not be that warm again through much of next week.
A noticeable push of cooler air will spread southward from Ontario and Quebec into the eastern Great Lakes and New England between tomorrow and Saturday.
A cold front from eastern Canada will slide southward along the East coast between late Friday and the end of the weekend. For the area from Philadelphia to Boston, where temperatures will reach the summery 80s each day through Friday, it will mean a noticeable change to cooler weather.
Average high temperatures in Chicago and New York City are in the mid-70s now, but for the next several days, temperatures will run 8-15 degrees above those long-term averages. Supporting this warmth is a flow aloft that originates over the Southwest:
Rain was common in the Northeast this morning, though Boston was still waiting as of 9 a.m. Their summer dry spell has continued.
There will be an increase in warmth and humidity in the Northeast that will not be reversed until the next cold front arrives.