Performance optimization: remove slow pyproj Lambert (200s→30s); use fast eccodes lat/lon arrays with linear interpolation; balanced=stride2 default; high=stride1 full res

Fix alignment: implement proper Lambert conformal reprojection using pyproj with RRFS sphere (R=6371229m); extract projection params from GRIB; eliminate griddata artifacts

Maximum quality & perfect alignment: stride=1 for high quality (no decimation); full RRFS NA 1799x1059 resolution; remove dynamic source decimation; cubic interpolation for Lambert→Lat/Lon; max_points=2.5M

High quality: set high=stride2 @1600x1200; dynamic source decimation tied to target grid; linear interpolation with NaN alpha to remove edge streaks

Fix: add quality_to_stride_and_grid helper; enable quality presets for stride/grid without NameError

Quality control: add fast/balanced/high; cache stride and render grid configurable; mask fill values; use nearest interpolation; pass quality through UI

NA alignment cache: build once lat/lon arrays for RRFS NA grid (decimated) and reuse for fast, accurate placement; no repeated heavy arrays

Alignment: resample via ecCodes lat/lon arrays with early decimation for NA; prefer accurate arrays path over bbox; adjust target grid to 480x360

Leaflet: render map inside iframe; normalize longitudes for field-based interpolation; add cfgrib-unfiltered attribute search fallback

Render Leaflet via iframe data URI to allow JS execution in Gradio HTML; should display overlay reliably

Add detailed logging and Debug Log panel; log NA slice ranges, parse path, extents, and timings; compute exact GRIB slice length

Map: normalize bbox longitudes to [-180,180] for correct Leaflet positioning of NA overlay

Fix UnboundLocalError: always set REFC lines for NA and non-NA paths; use unified refc_lines in return

NA 404 fix: resolve NA key by testing multiple official patterns and verifying .idx contains REFC; avoid slicing when file absent

Visualization: drop ecCodes lat/lon arrays path; use fast bbox-based rendering fallback for sliced NA

Visualization: ecCodes fallback now uses latitudes/longitudes arrays and values; render via interpolation path for reliable NA overlay

NA robustness: if sliced single-message file, parse first GRIB with ecCodes without requiring shortName; improved Nx/Ny detection and bbox fallback

NA: slice only first REFC message via HTTP Range for reliable parsing; reduces file size and avoids cfgrib/eccodes edge cases

Fix REFC visualization: fallback to ecCodes if cfgrib yields empty dataset; robust rendering for NA and small domains

Spaces config: drop sdk_version to fix 'Gradio version does not exist'

Add Hugging Face Spaces metadata to README (YAML front matter)

Add NA (North America) support: use prslev.3km and slice REFC via HTTP Range; decimate large grids for fast Leaflet rendering

Add RRFS REFC downloader + Gradio app with Leaflet overlay (REFC), NOAA S3 source; ignore data/ and GRIB files

initial commit