Monday 9 AM
This pressure analysis shows tightly packed isobars (lines of equal barometric pressure) surrounding a low pressure area centered over Ontario. The closer the isobars are to each other, the stronger the wind (there are other factors involved but the pressure gradient... the change in pressure over a given distance... is dominant).
Between today and tomorrow, the storm will move northeast through eastern Canada, and a high pressure area from the Midwest will toward the Middle Atlantic states. Tomorrow will be breezy across New England, but the change in map features will lead to weakening winds over the Great Lakes. In the video, you will see why Wednesday should be mild and tranquil throughout the Middle and North Atlantic states. However, a storm will be organizing in the Northern Plains at midweek, and that storm will then follow a path similar to the last one. This could mean another round of high winds for the Great Lakes, and then East Coast showers, late this week.
More than 110,000 lightning strikes occurred in the northeast third of the nation in the 24 hours ending at 11 a.m. EDT today (June 13).
This map shows the low pressure at the western edge. The isobars help define the location of the frontal boundary between the hot and cool air masses.
This map shows the area that could have damaging thunderstorms tomorrow and tomorrow night.
The Northeast regional radar at 10 AM showed a large area affected by showers and thunderstorms:
Whereas Andrea was centered in eastern South Carolina at 8 a.m., this satellite water vapor image shows the greatest concentration of moisture is well northeast of the surface circulation center
Quite a few models are in use, and this map shows there is widespread agreement on where the center of this storm is going.