Any time the blue lines extend below the 0 line on the graph above, something known as the North Atlantic Oscillation is in a negative phase. Essentially, this means the pressure difference between the Azores Islands and Iceland is very small and the upper level pattern, as a result, is likely very "congested" or blocked. This is the case this morning as high pressure sits across the central United States and over the NW Atlantic Ocean. What this is doing is locking low pressure in place over the Mid Atlantic and keeping our weather very unsettled in southwest Florida.
Brian
