6 to 10 and 8 to 14 day outlooks? What do they mean?

The notation for the categorical forecast indicated on the maps is as follows: A-above   N-near normal   B-below 
 
The temperature map shows regions with > 33% chance of being warmer (orange, "A"), colder (blue, "B"), or close to (unshaded, "N") historical average values for the calendar period of the forecast  (Dashes, "F").  Labels on the shaded lines give the probability (> 33%) of the more likely category (B or A).  Probability of N is always < 40%.
 
The precipitation map shows regions with > 33% chance of being wetter (green, "A"), drier (tan, "B"), or close to (unshaded, "B") historical median values for the calendar period of the forecast (dashes, "inches").  Labels on the shaded lines give the probability (> 33%) of the more likely category (B or A).  Probability of n is always < 40%.
 
In the southwest and other climatologically dry regions - there will be a greater than 33.3% chance of no precipitation and occasionally even a normal (i.e. median) value of zero - especially during the dry Seasons.  In such cases a forecast of near normal is effectively a Forecast of little or no precipitation. 
 
The climate prediction center uses 1981-2010 base period means for Temperature...precipitation...and 500-hpa heights as reference in the climate outlooks.


A technical discussion may be found by clicking here.


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.