Big diference in Senate and governor polls

One thing we find puzzling in national polls is that the Democrats are doing much better in governor's races than in senatorial ones. Does this reflect a different view of state vs. national issues? Below are recent polls in each category. Please note that we consider a race close until more than two polls show the divide more than 4 percent.

GOVERNOR
Democratic leads in blue. Republican in red
Republicans stand to lose 3, with 9 more seats in doubt. Two Democratic seats are in doubt
Democrat seats in doubt
Oregon 0, 1%
Rhode Island: 3,2%

Republican seats in doubt
Arizona: 2, 1,1,3%
Georgia 2%
Iowa; 4%
Ohio 7, 4%
Maine: 0%
Minnesota 0%
Nevada 2, 3, 1, 2, 1%
New Mexico 13, 2%
South Dakota 4%

Republican loss
Illinois: 18, 9, 16%
Michigan 5, 15%
Wisconsn 13, 7, 5, 0%

SENATE
Key Senate Races
Democratic lead in blue, GOP in red
Most recent poll to right

Democratic seats in danger:8. GOP seats in danger: 5

Democratic seats in danger
Florida: 10,4, 3, 4, 4, 3, 4, 4, 3, 6% 
Indiana 1, 2%
Minnesota (Smith seat) 4, 7%
Missouri: 8, 2, 0, 1, 4, 6, 2, 2 0%
Montana 3%
New Jersey 4, 2%
North Dakota: 3, 4, 5%
Wisconsn 2%
Republican seats in danger
Arizona 4-18%
Nevada: 1, 6, 4, 1%
Mississippi 3%
Tennessee 4%
Texas 2, 6, 2, 4%