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Wind Speed Probabilities-based Tropical Cyclone Danger Graphic
Data Mining Tool
Outreach / Education
The Tropical Analysis and Forecast Branch (TAFB) is providing a Tropical Cyclone Danger Area graphic based on the 34-kt wind speed probabilities through 72-hours from the latest tropical cyclone advisory for an active tropical cyclone. The graphic outlines avoidance areas using the 10% and 50% 34-kt wind speed probability contours from the latest tropical cyclone advisory issuances for both the Atlantic and East Pacific basins (Figures 1 and 2). The current Tropical Cyclone Danger Area graphic utilizes the mariners 1-2-3 rule to outline avoidance areas through 72 hours for active tropical cyclones. Feedback from users indicated that the use of the 1-2-3 methodology has led to "over-warned" large avoidance areas. The 1-2-3 methodology assumes an average forecast track error of 100 nmi at Day 1, 200 nmi at Day 2 and 300 nmi at Day 3 rule (Figure 3). These values are well above the most recent 10-year averaged forecast track errors of 50 nmi at Day 1, 85 nmi at Day 2 and 120 nmi at Day 3.
Product information and survey access
Point of Contact
Hugh Cobb firstname.lastname@example.org
Document (e.g. PDD)
(OPTIONAL) If you have a sample image, please upload.
Comment Start Date:
2015-05-15 Comment End Date: 2015-11-30
Approved for Operational Implementation
7831_signed approval memo (1).pdf
Last edit date to this meta-data: 2019-07-08