• Cloud streets (lines of cumulus-type  or “puffy” clouds) typically form when cold air blows across warmer waters.  As the air moves over the water, it picks up moisture and is warmed.  This allows convection to develop and cumulus clouds to form just offshore.  The effect is also often seen over the Great Lakes in late fall and winter and is linked to “lake effect snows”.

• In the images on your right, northwesterly winds (winds from the northwest) are blowing from eastern Canada, over New England and then out into the north Atlantic.

• On each image, the cloud-free area between the land and the back edge of the cumulus clouds is almost a uniform distance from the shore.  This is related to how long it takes the air to warm and moisten and for clouds to form.  Notice that the cloud line forms first where the over-the-water trajectory starts the earliest (e.g., small bays).

• Cumulus clouds develop initially.  These grow into low-topped towering cumulus clouds and eventually reach the inversion level.  Then the clouds spread out into stratocumulus.  As the clouds grow, they are more likely to produce snow showers.

NASA's TERRA Satellite:

• The Terra spacecraft (formally known as EOS-AM) was successfully launched on Saturday, December 19, 1999 at the Vandenberg Air Force Base (VAFB) in Lompoc, California. It is flying at an altitude of 705 km (438 miles) observing the Earth. The life expectancy of the Terra mission is 6 years. It will be followed in later years by other EOS spacecraft that take advantage of new developments in remote sensing technologies. [Terra 3D Animation], [Animation showing Terra Orbit]

• Terra's orbit around the Earth is timed so that it passes from north to south across the equator in the morning, and thus it passes over us at the same local time every day, approximately 10:30-10:45 a.m.