Mild conditions prevailed for Halloween, and the first few days of November are rather warm, too!
Atlanta registered a morning low of 57 degrees on Wednesday morning, and the afternoon high climbed to 76. This is approximately 5-10 degrees above the average daily lows and highs for early November for the city.
Since then, the PNA has trended negative, allowing a ridge of high pressure to develop in the upper levels of the atmosphere over the Eastern United States.
What is causing the mild Autumn temperatures to climb closer to Summer territory?
Pacific North American Pattern trending negative
Remember that chilly dip in the jet stream in Mid-October that brought widespread freezing temperatures to Metro Atlanta? That dip was associated with the positive phase of the Pacific North American (PNA) Pattern.
Ensemble forecast models indicate the PNA will remain negative through mid-November.
This means that a ridge will continue to dominate the regional weather over the Eastern United States.
Upper level atmospheric ridges are associated with high pressure at the surface. Sinking air within the ridge causes high pressure, which prevents cloud cover and rain showers to develop.
As a result, sunny days will feature warmer than average temperatures, and temperatures will trend above average during the night time hours as well.