Mike the blue arrows are direction and speed (size of arrow).
Grey areas are fast moving jet streams that are sort of bad for astronomical viewing, read this Cloudy nights info:
"3. High Altitude effects.
Effects at this altitude are caused by fast moving “rivers” of air know as Jet streams. Wind shears at around the 200-300mb altitude level can cause images to appear stable, but very fuzzy, and devoid of fine detail. There isn’t anything the observer can do to prevent these effects, but forecasts are available, to help predict weather a Jet stream is present over your area... "
Whole thing here:
http://www.cloudynights.com/howtos2/seeing.htm