WOAY-TV (Oak Hill, WV): Following a hot and dry summer, does Mother Nature have a turn of events for the fall season?
Chief Meteorologist Chad Merrill and Forecaster Braden Petry break it all down:
Below are the most significant pattern drivers for the Fall Season:
- Transition into La Nina: Equatorial Pacific is cooling below average and the atmosphere is already in La Nina mode (Multivariate Index supports this). Temperature and rainfall patterns associated with La Nina in control during the fall:
- The Pacific-Decadal Oscillation (PDO) will remain in a cool phase through autumn. Below are the temperature and rainfall patterns in a negative PDO fall:
- The Atlantic Multi-Decadal Oscillation (AMO) will stay in a warm or positive phase this fall. Below are the temperature and rainfall patterns in a positive AMO fall:
- High Sunspot (Solar Flux) activity: We are approaching the peak of Solar Cycle 25, so this year due to the high solar influx, this was included as one of our input signals into the autumn forecast. Below is the solar cycle trends and temperature and rainfall patterns in a high solar flux autumn:
- Quasi-Biennial Oscillation: Cyclical shifting of wind direction above the equator that last 12-14 months. We will be in a positive phase this fall and here are the temperature trends with this pattern:
StormWatch 4 U.S. temperature pattern this fall based on analog years that best match the cycles indicated above: Warm pattern, except for the Northwest coast with a likely active storm pattern and Florida and the eastern Gulf Coast with clouds and rain associated with the multiple tropical systems.
StormWatch 4 U.S. Precipitation pattern shows an elevated risk for more rain than average from the Carolinas into Florida thanks to a busy hurricane season while the interior East into the Lower Mississippi Valley and southern Plains can expect drier than average weather. There will be an elevated brush fire risk for the interior East. An active storm track along the Northwest coast and Upper Mississippi Valley will trigger more rain than average. No signal for a wet or dry fall for the remainder of the Central and western U.S. The brush fire season will see more robust activity in the interior West. Smoke will continue to generate poor air quality in parts of the U.S., depending on wind direction. 
StormWatch 4 local fall outlook shows a continuation of a dry pattern this fall. However, there will be bursts of heavy rain in September, with October into early November being the driest period of the fall. Fall foliage will occur earlier (early October) and not be as vibrant as previous years thanks to the stress of the drought on the trees this summer. 
StormWatch4 local temperature outlook shows a warm autumn with a delayed start to the ski season at Snowshoe (usually gets underway on Thanksgiving weekend) and lower heating costs in the latter third of the season.
StormWatch4 monthly temperature trends for the upcoming fall season show frequent cold fronts bringing heat relief in September, very warm periods in between transient cool blasts in October and a strong signal for a chilly first day of November, then a week of very warm temperatures before a major pattern shift brings near average temperatures for the remainder of the month. Our first inch snowfall prediction is later than normal, see image below individual monthly temperature trends: 
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