here is the COASTAL relative air to keep in mind



MOST coastal air comes from across the water which runs the humidity through the roof.....

the east coast has the benefit of the relatively dry continental air flow coming across to the sea level track, that is why you will see thet 90-95% of all the -DA data come from the east coast.....

rare air gets to -DA in many places, i've even seen it here in dallas but it is that once in a 100 year time situations, those are rare rare rare....the northeast gets REGULAR and CONSISTENT -DA....