The Rapid Refresh Forecast System, RRFS, has moved from early access evaluation to pre-production status. The next step for this new model is for it to enter production, which is currently scheduled for early October, 2026.

When RRFS enters production, several other models will be retired. This is described by the USA National Weather Service in this service change notice. The NAM models will be removed when RRFS goes into production.

RRFS will eventually replace HRRR as well, but there is not yet an implementation date for that.

With the change from early-access to pre-production, the RRFS data has changed in several ways, and the support for RRFS on the LuckGrib servers reflects those changes. In the early access model, which was hosted on Amazon Web Services servers, the entire North American domain was offered at full resolution, with hourly updates and hourly forecast data. Now that the model has been moved off of Amazon and into the NOAA infrastructure, the team is much more resource constrained and the amount of data available has been reduced. (This may be resolved in the future as it sounds like the future models will be hosted in the cloud and have fewer resource constraints.)

There are now five versions of the RRFS model: four high resolution nests and the full area domain.

The four high resolution nest versions of RRFS are similar to how HRRR data is offered: CONUS (3km), Alaska (3km), (new) Hawaii (2.5km) and (new) Puerto Rico (2.5km.) There are two variants of each of these models:

• an hourly updated model with forcast data every 15 minutes out to 18 hours
• an extended model which runs every 6 hours with forecast data out to 84 hours (3.5 days.)

HRRR has a special sub-hourly wind version of its model covering CONUS. There is no longer any need for a normal RRFS and a sub-hourly RRFS - these two models are rolled into one and sub-hourly data is available in all four of these high resolution domains.

The extended forecast version of HRRR, HRRR-48, extended the forecast data out to 48 hours. RRFS’s extended hours going to 84 hours is very welcome. The extended forecast models are available for the 00Z, 06Z, 12Z and 18Z synoptic times, and take roughly 3.5 hours to be process and to appear (so, for example, the 00Z model appears at roughly 03.5Z.

These four models are called nests, which is to say, they are sub-domains of the larger North America native RRFS domain.

In addition to the four nests, LuckGrib is also currently providing two versions of the large North America domain. This isn’t ideal, but is what is possible with the currently available data.

• there entire North America domain is available at a 13km resolution, with forecasts extended to 84 hours, with hourly forecast data available.

• a full 3km resolution version of the North America domain is available with forecast data every 3 hours to 84 hours.

The two full North America domain models are available at the four synoptic times (00Z, 06Z, 12Z and 18Z.) What is missing from the original evaluation version of RRFS is the hourly updated full resolution model, with hourly forecast data. The early evaluation RRFS model was similar to HRRR, only vastly larger. The pre-production version still has the full resolution data available, although its available every 6 hours with restrictions on the combination of resolution and hourly forecast data.

This North America domain model is a dramatic improvement over what HRRR is offering, and should be very welcome to sailors navigating coastal waters around North America, as well as the Caribbean, passages to/from Hawaii, or out to Bermuda. If you happen to be navigating in an area covered by one of the four nests, those may become your preferred model. Outside the four nests, the two versions of the large North America domain model will offer great benefit.

Thanks to the entire RRFS and NWS/NOAA teams working on this new model! Your work is appreciated.