105 lines
5.5 KiB
Markdown
105 lines
5.5 KiB
Markdown
# RRFS (Rapid Refresh Forecast System) Data Assessment
|
|
|
|
## Overview
|
|
|
|
RRFS is NOAA's next-generation convection-allowing ensemble forecast system, intended to replace HRRR, RAP, NAM-NEST, and HREF. As of March 2026, RRFS is in operational evaluation — the ensemble post-processing products are publicly available on AWS S3, but the full deterministic model output with pressure-level fields is not yet publicly distributed.
|
|
|
|
## Data Availability
|
|
|
|
### AWS S3 Bucket: `noaa-rrfs-pds`
|
|
|
|
Two public prefixes with identical content:
|
|
- `rrfs_a/refs.YYYYMMDD/HH/enspost/` (primary)
|
|
- `rrfs_public/refs.YYYYMMDD/HH/enspost/` (mirror)
|
|
|
|
### Run Schedule
|
|
- 4x daily: 00Z, 06Z, 12Z, 18Z
|
|
- Data available ~2 hours after init time
|
|
- Recent data goes back about 10 days before being pruned
|
|
|
|
### Available Products (CONUS)
|
|
|
|
| Product | File Pattern | Contents | Usefulness for Propagation |
|
|
|---------|-------------|----------|---------------------------|
|
|
| `avrg` | `refs.tHHz.avrg.fNN.conus.grib2` | Ensemble mean | Only APCP (precipitation accumulation). **Not useful** — missing temp, dewpoint, wind, pressure, refractivity profile |
|
|
| `eas` | `refs.tHHz.eas.fNN.conus.grib2` | Exceedance probability | APCP/ASNOW exceedance probabilities. **Not useful** for propagation scoring |
|
|
| `ffri` | `refs.tHHz.ffri.fNN.conus.grib2` | Flash flood risk index | PPFFG exceedance. **Not useful** |
|
|
| `lpmm` | `refs.tHHz.lpmm.fNN.conus.grib2` | Ensemble mean (alternate) | APCP only. Same limitation as `avrg` |
|
|
|
|
### Forecast Hours
|
|
- f01 through f07 (1-7 hour forecasts)
|
|
- ~1.5MB per file for ensemble mean CONUS
|
|
|
|
### Grid
|
|
- 3km CONUS domain (same as HRRR)
|
|
- Lambert Conformal projection
|
|
- GRIB2 format with standard .idx files
|
|
|
|
## Key Finding: RRFS Public Data is NOT Sufficient for Propagation Scoring
|
|
|
|
The publicly available RRFS data on S3 contains **only ensemble post-processing products** — primarily precipitation statistics. It does NOT include:
|
|
|
|
- Surface temperature (TMP:2m)
|
|
- Dewpoint temperature (DPT:2m)
|
|
- Surface pressure (PRES:surface)
|
|
- Boundary layer height (HPBL)
|
|
- Precipitable water (PWAT)
|
|
- Wind speed/direction (UGRD/VGRD:10m)
|
|
- Cloud cover (TCDC)
|
|
- Pressure-level profiles (TMP/DPT/HGT at 1000-700mb) for refractivity gradient computation
|
|
|
|
These fields are essential for propagation scoring (all 9 factors). HRRR provides all of them.
|
|
|
|
## RRFS vs HRRR Comparison
|
|
|
|
| Feature | HRRR | RRFS (Public) |
|
|
|---------|------|---------------|
|
|
| Resolution | 3km | 3km |
|
|
| Update frequency | Hourly | 4x daily (00/06/12/18Z) |
|
|
| Forecast range | 18h (48h from 00/06/12/18Z) | 7h (from public data) |
|
|
| Surface fields | Full (TMP, DPT, PRES, wind, cloud, precip) | APCP only |
|
|
| Pressure levels | 8 standard levels (1000-700mb) | Not available publicly |
|
|
| Refractivity profile | Derivable from pressure-level T/Td/P | Not possible |
|
|
| S3 bucket | `noaa-hrrr-bdp-pds` | `noaa-rrfs-pds` |
|
|
| Byte-range requests | Yes (.idx files) | Yes (.idx files) |
|
|
| Historical depth | ~2 days on S3 | ~10 days on S3 |
|
|
|
|
## Recommendation
|
|
|
|
**Continue using HRRR as the primary data source.** RRFS public data is not yet suitable for propagation scoring due to missing atmospheric profile and surface fields.
|
|
|
|
Monitor for:
|
|
1. NOAA making full RRFS deterministic output public (likely when RRFS becomes the operational replacement for HRRR)
|
|
2. Additional fields being added to the ensemble post-processing products
|
|
3. NOMADS distribution of full RRFS output (currently returns 403)
|
|
|
|
When RRFS full output becomes available, key advantages would be:
|
|
- Ensemble spread information (confidence intervals on propagation scores)
|
|
- Potentially improved boundary layer and moisture forecasts from the FV3 dynamic core
|
|
- Longer forecast horizon for propagation prediction
|
|
|
|
## Meteorologist Feedback (March 2026)
|
|
|
|
From a meteorologist familiar with Gulf region propagation:
|
|
|
|
**Model choice validation:**
|
|
- HRRR is confirmed as the best short-term (0-48h) choice for low-level inversions and water vapor content. Higher vertical resolution in the boundary layer and tighter grid spacing give it the best handle on moisture — critical since humidity is our highest-weighted scoring factor (20%).
|
|
- **NAM should be avoided** — substantially over-estimates low-level water content, especially in the western Gulf region. Over-does fog and water vapor discontinuities. Would produce false-positive ducting predictions in exactly the areas where ducting matters most.
|
|
- **GFS is better for days 2-5** forecasts, with a more pessimistic (and more correct) stance on moisture. Worth considering if we add a multi-day propagation forecast view.
|
|
|
|
**RRFS transition notes:**
|
|
- HRRR will be operationally replaced by RRFS in the next few years
|
|
- The meteorologist expects RRFS files may use netCDF format (current experimental output on S3 is GRIB2 — the full operational output format may differ)
|
|
- The transition should be "fairly straightforward" — the scoring algorithm itself won't change, only the data ingestion layer
|
|
- RRFS is already available experimentally but (as documented above) the public output lacks the fields we need
|
|
|
|
**Implications for our architecture:**
|
|
- Keep HRRR as primary source — validated by domain expert
|
|
- Don't use NAM for anything moisture-related
|
|
- The `Propagation.Scorer` module is data-source-agnostic by design — when RRFS becomes available, only the fetch/extraction layer needs to change
|
|
- If we add forecast beyond 48h, consider GFS as a supplementary source for days 2-5
|
|
|
|
## References
|
|
- AWS S3: `s3://noaa-rrfs-pds/`
|
|
- NOAA RRFS: https://gsl.noaa.gov/focus-areas/unified_forecast_system/rrfs
|
|
- NOAA EMC RRFS: https://github.com/NOAA-EMC/rrfs-workflow
|