National Convective Weather Forecast 2 (NCWF2)

National Convective Weather Forecast 2 (NCWF2)

The National Convective Weather Forecast (NCWF) product, designed and implemented by the National Centerfor Atmospheric Research (NCAR), provides a diagnose of the current locations of convective hazards to aircraft as well as a depiction of future locations of existing convective hazards for lead times of 30, 60, 90, and 120 min given in a probabilistic sense (see movie loop at the bottom of the page).

Significant weather of Base Interest field obtained by combining Unisys VIL and NLDN Cloud–to–Ground lightning data (mouse over image to see Convective Hazard Detection)
Significant weather of Base Interest field obtained by combining Unisys VIL and NLDN Cloud–to–Ground lightning data

Both the convective hazard detection field and the forecasts update every 5 minutes. The NCWF product is currently available on the Experimental Aviation Digital Data Service (ADDS) Convection page as well as the Experimental ADDS Flight Path Tool. The target users of NCWF2 are general aviation, airline dispatch offices, and FAA Traffic Management Units (TMU). NCWF was developed by the Convective Weather Product Development Team through sponsorship by the Federal Aviation Administration's (FAA) Aviation Weather Research Program (AWRP). The Convective Weather Product Development Team consists of MIT Lincoln Laboratories, National Weather Service's Aviation Weather Center (AWC), and the National Center for Atmospheric Research (NCAR).

The Base Interest or Significant Weather field (shown above) indicates where precipitation with VIP >= 1 is falling. The product is the result of combining the VIL field generated from the WSR–88D national radar mosaic by Unisys with and the cloud–to–ground lightening data from the National Lightning Detection Network (NLDN). The Significant Weather field is depicted based on a 6 level intensity scale. The 6 levels fundamentally correspond to the Video Integrator and Processor (VIP) levels (see images above and to the right) that were developed to convey storm intensity for aviation interests.

Loop from –120 to + 120 min showing successive Significant Weather detections and the corresponding probabilistic forecast of convection
Loop from –120 to + 120 min showing successive Significant Weather detections and the corresponding probabilistic forecast of convection

The National Convective Weather Hazard Detection (NCHD) is intended to indicate areas of thunderstorms that pose an aviation hazard. This field is generated by performing automated Quality Controls to the WSR–88D national moasic of VIL, removing areas of the light precipitation and filtering out areas of stratiform precipitation from the Significant Weather field. Probabilistic forecasts of 30, 60, 90 and 120 min are then generated using the NCHD field, observed tracks and trends in the NCHD, environmental conditions provided by the Rapid Update Cycle (RUC) model run by the National Center for Environmental Prediction (NCEP), and climatological information. The probabilistic forecast indicates the likelihood or chance that storms posing an aviation hazard will exist at a particular location at a given time.

The NCWF forecast product is not intended to forecast thunder storm formation, but does very well with long–lived mature systems. The NCWF forecast products also includes information on storm trends which are represented as areas of decreased/increasd probabilities depending on whether the storm was observd to be dissipating or in a region favored for growth. While NCWF does not explicitly treat storm initiation, the growth algorithms will capture new storm formation in the vicinity of existing storms. Work on improving automated methods for forecast initiation, growth and dissipation of storms and extending these forecasts to longer lead times through blending with probabilistic NWP forecasts is ongoing.