Reference
Forecast terms
Abbreviations used in the storm selector, model panel, and map popups.
Basin codes
- AL
Atlantic
North Atlantic basin, including the Caribbean Sea and Gulf of Mexico.
- EP
Eastern Pacific
Eastern North Pacific basin east of 140 degrees west.
- CP
Central Pacific
Central North Pacific basin between 140 degrees west and the International Date Line.
- WP
Western Pacific
Western North Pacific basin, the main typhoon region monitored by JTWC/JMA.
- IO
North Indian Ocean
North Indian Ocean basin, including the Bay of Bengal and Arabian Sea.
- SH
Southern Hemisphere
Southern Hemisphere tropical cyclone basins used by JTWC ATCF data.
Intensity categories
| Code | Meaning | Minimum wind |
|---|---|---|
TD | Tropical Depression | 0 kt |
TS | Tropical Storm | 34 kt |
C1 | Category 1 | 64 kt |
C2 | Category 2 | 83 kt |
C3 | Category 3 | 96 kt |
C4 | Category 4 | 113 kt |
C5 | Category 5 | 137 kt |
Agencies
- NHC
National Hurricane Center
NOAA agency responsible for Atlantic and eastern/central Pacific tropical cyclone advisories.
- JTWC
Joint Typhoon Warning Center
U.S. agency providing tropical cyclone warnings for western Pacific, Indian Ocean, and Southern Hemisphere basins.
Units
- kt
Knot
Wind-speed unit equal to one nautical mile per hour, about 1.852 km/h.
- km/h
Kilometers per hour
Metric wind-speed unit shown alongside knots in map popups.
- mph
Miles per hour
Imperial wind-speed unit used in some public forecasts and settings.
- MSLP
Minimum sea-level pressure
Estimated storm-center pressure, usually reported in millibars or hectopascals.
Model abbreviations
Model identifiers are ATCF shorthand. Each link points to the operating agency's official documentation for that model family.
Official
The human-issued forecast from the warning agency. In Atlantic and east Pacific storms that means NHC; in western Pacific and other JTWC basins it follows JTWC guidance.
Official agency forecast
AI
NOAA's deterministic AI global forecast stream, designed as a fast machine-learning counterpart to traditional global model guidance.
NOAA deterministic AI global model
The mean track from NOAA's AI global ensemble family. It is a probabilistic centerline rather than a single deterministic model run.
Mean of NOAA's 31-member AI ensemble
A hybrid ensemble mean that blends AI-driven guidance with physics-based ensemble output, useful when the spread is large.
62-member hybrid AI + physics ensemble mean
Global models
ATCF's GFS identifier. GFS is NOAA/NCEP's primary global numerical prediction system and one of the baseline models for tropical guidance.
ECMWF's Integrated Forecasting System. It is often referred to as the European model and is a core global forecast reference.
Availability varies by basin
The Met Office Unified Model, a global numerical model family used for weather and climate prediction across several time scales.
Canada's Global Deterministic Prediction System, also commonly surfaced as CMC or GDPS in model guidance displays.
The U.S. Navy global model produced through FNMOC, descended from NOGAPS and used as a global medium-range guidance source.
Hurricane models
One HAFS configuration. HAFS is NOAA's next-generation hurricane model with ocean coupling and storm-scale data assimilation.
A second HAFS configuration, usually read alongside HAFS-A to compare model physics and initialization differences.
NOAA's legacy high-resolution hurricane model, built around nested storm-following grids for track, intensity, and structure guidance.
A NOAA hurricane model stream listed with NCEP hurricane products. It is often viewed alongside HWRF and HAFS guidance.
Consensus
A consensus aid. Consensus tracks combine selected objective guidance, giving forecasters a stable center of gravity across models.
Ensemble means
The GEFS ensemble mean. It summarizes the NOAA global ensemble member spread into a single average track.
The Canadian ensemble mean, derived from ECCC's Global Ensemble Prediction System.
The FNMOC ensemble mean, used here as the Navy ensemble centerline when available in ATCF guidance.
Ensemble members
Individual AI ensemble members. The members show spread and alternate solutions, while the mean compresses them into a single guide.
Individual AI ensemble member tracks
Individual GEFS member tracks. They show the spread of solutions that the ensemble mean averages together.
Individual Canadian ensemble members from the ECCC ensemble system, shown as lower-emphasis spread tracks.
Individual FNMOC ensemble members, shown as a spread family for alternate global solutions.