As part of an ongoing project to explore the viability of various forecast tools with respect to forecasting higher latitude tropical cyclone impacts in the Atlantic basin, experimental analog forecast tracks have been developed for all active storms in the Atlantic basin. These tracks are derived by comparing a storm's current location, intensity, motion, and time of year to those from all other storms from 1950-2011. Similarity scores are computed for all storms at all times and then ranked from best to worst matching. The ten best-matching unique storms are taken to create the analogs shown here.
The weightings on current location, intensity, storm motion, and time of year in the current routine are as follows:
- Location: 0.025 point for every km away from current location
- Intensity: 0.25 point for every kt away from current intensity
- Motion (Speed): 1 point for every 2 kt away from current motion
- Motion (Direction): 0.5 point for every 10 deg away from current direction
- Time of year: 0.075 point for every day away from current date
A score of 2.5 thus occurs for differences of 100 km (roughly 1 degree of latitude or longitude), a time of year difference of 33 days (roughly 1 month), an intensity difference of 10 kt, a forward speed difference of 5 kt, and a forward direction difference of 50 degrees (roughly W vs. NW). Similarity scores less than 5 indicate a very good match; similarity scores over 10 indicate poorer matches. As a result, unique or rare storms will inherently have larger scores than those that are less unique. The raw output from the analog creation routine is available by changing the file extension on the analog track plots to txt from png.
Currently, plots of the analog tracks, highlighting the past and future tracks of these best matching storms, are created. The current location of the storm and intensity designation marker are shown for reference. The analog track plots list the ten analogs in order from best to worst to aid in identifying each track on the map.
Disclaimer: The availability and timeliness of these data are not guaranteed. The data displayed here should NOT be used for making life and death decisions. If anything on these plots causes confusion, disregard all of the information on these pages. Always take the word of the official sources when preparing for any potential storm impact.
Site and Contents © 2007-2013, Clark Evans (with help from Shane Young).