Haze develops under stable conditions from an upper-level confluence of high pressure cells, which cause subsidence and a marked surface inversion. When coupled with a light northerly flow, visibility will remain unrestricted. If the wind is forecast to veer
to a northeasterly direction, visibility may be reduced to 3-5 miles. Once the wind veers southeasterly, visibility will gradually improve. Instability, high winds, and the movement of the high pressure cell will also cause the haze to dissipate and visibility to improve.
During July and August, with a stationary ridge at 500 mb between Georgia and the Mississippi River, resultant surface inversions reduce the surface visibility to 2-4 miles. The worst visibility will be in the early to mid-morning hours.
Smoke is most detrimental to flight operations when it is in a layer aloft. During July and August, flight-level visibility may be reduced to 1 mile or less. Pilots reports (PIREPs) in the local area and northward have reported tops of this haze layer as high as 18,000 feet, while surface visibility may only be slightly affected. Haze usually forms in combination with the smoke layer aloft. These layers are sometimes as high as 5,000-8,000 feet (the average base of the subsidence inversion) and will continue until a change of wind flow or air mass relieves the situation.