A review of the October 16, 2012 GFS runs indicate that the model was outstanding in its 204 hour 500 mb forecast for October 24, 2012 at 18 Z. The 60 hour forecast and the previous 204 hour forecast are provided below. The upper air pattern is considered to be easier to forecast than surface weather since there are less influences to consider in the model such as topography, convection, oceanic effects, soil moisture, vertical velocity, snow cover, albedo, etc. The weather charts indicate that a strong ridge is providing mild weather up and down the East Coast and this pattern is normally conducive for a tropical storm to track northward up the coast. However, the broad trough and upper low that is forecast to dig down across the Ohio Valley and the Northeast is forecast to push Tropical Storm Sandy away from the coast. The GFS model is forecasting some interaction with the upper trough and Sandy which currently suggests some rain will be entrained into the upper trough but the entire storm will be not be completely captured by the upper-level circulation. If the entire storm is captured, then a major storm event can occur in the Northeast and the NYC metro area next week on or before Halloween. Otherwise, if the entire storm is not captured, the relatively strong blocking pattern that is forecast at 500 mb will result in a cutoff low over the Northeast that will generate rain and wind next week. The 84 hour NAM forecast is similarly indicating that the upper trough will interact with or phase in with the 500 mb circulation from Sandy. Future runs and model comparisons need to be analyzed closely through this weekend.
George Wright is a Certified Consulting Meteorologist for Wright Weather Consulting, LLC. George is also a meteorologist with ABC News and Cablevision News 12. Our website is WrightWeather.com. George Wright is on Twitter @gwweather.
