Just Because - An Essay on What Seasonal Outlooks REALLY mean.

Suppose you have a bowl full of marbles. In that bowl there are 33 blue marbles, 33 green marbles and 33 black marbles. If you randomly grab a marble from this bowl, what is the chance of grabbing a blue marble? If you said 33% chance you are correct. There are equal chances (33%) that you draw a black marble, a green marble or a blue marble out of that bowl. What if you stack the bowl with 50 blue marbles, 25 green ones and 25 black ones? Then there would be a 50% chance for a blue marble, and there would be a 50% chance for a NON-BLUE marble. So when you see a seasonal forecast outlook indicating "EQUAL CHANCES", that means any of the 3 outcomes - ABOVE, NEAR, BELOW - are equally likely. Also, if you see a seasonal forecast indicating one outcome is more likely than the other 2, such as a 40% chance for ABOVE NORMAL temperatures, keep in mind that means there is still a 60% chance the other two might occur. In this example, ABOVE NORMAL is simply more likely to occur (the blue marble) than either NEAR (the green marble) or BELOW NORMAL (the black marble). Once in a while you'll see a high confidence forecast in the 6-10 day or 8-14 day outlook for either ABOVE NORMAL or BELOW NORMAL. Again, the high chances reflect HIGH CONFIDENCE that the outcome will be WARM or COLD (for temperatures). These forecasts provide NO information regarding the magnitude of how far ABOVE or BELOW normal it might be. According to CPC's latest outlook, Maryland has EQUAL CHANCES for warm, cold or normal temperatures during Dec-Jan-Feb, and most of the state has EQUAL CHANCES for wet, dry or normal precipitation this winter except for the eastern section. The probability for above normal precip there is between 34% and 40%. Keep in mind that skill levels for these types of forecasts are rather low. So what does EQUAL CHANCES really MEAN? It means we don't really know, the signals we use are mixed, and it could go any of the 3 ways.