Guide to Early Cycle Track Plots

This page lists the TECH identifiers of the various intensity forecast aids that may appear in the early cycle track plots on this site. To learn more about TECH identifiers, click here. For general information about the difference between late cycle and early cycle forecast aids, click here. To learn what a vortex tracker is, click here.

TECHs of the forecast aids shown in this plot

The TCGP plotting system is currently configured to plot the tracks of the early cycle forecast aids, as well as the tracks of select late cycle guidance which have been interpolated to the same time as the early cycle guidance. If one of the forecast aids listed here does not appear in the plot, this means that it was not available in the source a-deck at the time the plot was created. When a system has been newly designated or upgraded to a tropical depression, it is common to only have a few forecast aids available.

Official forecast:

• OFCI: NHC official forecast from previous forecast cycle (adjusted 6 hours to present cycle)

Early cycle track forecast aids:

• XTRP: Extrapolation using past 12-hr motion (only shown for first 24-hr)
• CLP5: CLImatology and PERsistence model (CLIPER), 5-day version (statistical)
• BAMS: Beta and Advection Model, Shallow layer (single layer trajectory model)
• BAMM: Beta and Advection Model, Medium layer (single layer trajectory model)
• BAMD: Beta and Advection Model, Deep layer (single layer trajectory model)
• LBAR: Limited area BARotropic model (single-layer regional dynamical model)

Multilayer global-dynamical models - deterministic runs:

In addition, the following late cycle track forecast aids are also plotted on the early cycle track plots. Generally, these are very complex models that are run at various national modeling centers. All of these forecast aids are adjusted 6 hours ahead to the present cycle:

• AVNI/GFSI: Previous cycle's run of the NWS Global Forecast System (GFS) model
• CMCI: Previous cycle's run of the Environment Canada Global Environmental Multiscale (GEM) model
• EGRI: Previous cycle's run of the UK Met Office model with subjective quality control applied to the tracker (the official version, distributed on GTS)
• UKMI: Previous cycle's run of the UK Met Office model using the development tracker (no quality control, only run at 0000 and 1200 UTC)
• NGPI: Previous cycle's run of the Navy Operational Global Prediction System (NOGAPS)

Multilayer regional-dynamical models:

• HWRI: Previous cycle's run of the NWS/Hurricane Weather Research and Forecasting (HWRF) model
• GFDI: Previous cycle's run of the NWS/Geophysical Fluid Dynamics Laboratory (GFDL) model
• GFTI: Previous cycle's run of the NWS/GFDL model (using the GFS vortex tracker)
• GFNI: Previous cycle's run of the NWS/GFDL model (using the NOGAPS model fields)
• COTI: Previous cycle's run of the Navy COAMPS model

Consensus track aids

Finally, the following consensus track aids are plotted on the early cycle track plots. Generally, these are a weighted average of several diverse models, or a simple average of all the ensemble members of a particular ensemble forecasting system. In general, the consensus aids are considered early track aids since they use the interpolated output of the late models.

• AEMI: Previous cycle's ensemble mean of the NWS Global Ensemble Forecast System (GEFS) (adjusted 6 hours to present cycle)
• TCON: Average of GHMI, EGRI, NGPI, HWFI, and GFSI
• TVCA: Variable consensus (weightings can vary) of AVNI/2, EGRI/2, GHMI/2, HWRI/2, EMXI/2, GFNI/2
• TVCE: Variable consensus (weightings can vary) of AVNI/2, EGRI/2, NGPI/2, GHMI/2, HWRI/2, EMXI/2, GFNI/2
• TV15: Variable consensus (weightings can vary) of various Stream 1.5 models under evaluation by HFIP

Frequently asked questions

Often users ask why other forecast aids are not included in the early cycle track plots. This section is meant to answer these questions.

Where can I find more information about the details of these different models and forecast aids?

In the future we plan to offer a comprehensive guide to all the forecast aids featured in this site. In the meantime, please refer to the very useful Technical Summary of the National Hurricane Center Track and Intensity Models.

Why don't you include the projections of the European Centre for Medium Range Forecasting (ECMWF) model?

The ECMWF model is run by a 28-nation European consortium who jointly fund the operations and development of that model. As such, access is generally restricted to member states or commercial users who are willing to pay for the model output. They do provide low resolution fields of their deterministic run, although these are at too coarse of a resolution to run a vortex tracker on.

Why don't you include the projections from the North American Model (NAM)?

The NAM model's track projections are normally not very skillful compared with the other dynamical track models shown here. In the future, TCGP may feature another type of plot for experimental or less skillful track models. We will include the NAM in that new type of plot.

Why don't you include the other consensus track models, such as GUNA, CGUN, TCON, and TVCC?

The consensus forecast aids for track are normally a combination of the same 4 or 5 models, so showing TCON and the variable consensus aids (TVCA and TVCE) is probably enough. The corrected consensus aids, such as CGUN, CCON, and TVCC, have not proven their worth as forecast aids.