Live bundle: encode radar textures as lossless WebP (method=4) instead of PNG — ~25% smaller bundles, lossless (gray values unchanged). Client loads textures as image/webp; logo + downloaded export stills stay PNG.

Live: every site uses the low-latency chunk feed (in-progress volumes shown), archive-bucket fallback. Short-lived caches now that all sites cache: drop a site's decoded volumes ~10 min after last view (touch-on-read LRU, _CHUNK_TTL=600s); chunk files pruned at ~80 min (covers the 65-min loop); live cache ttl 45s + rtsec 120s for all sites.

UI + export: rename 'Load hour' button to 'Go', hide the 'Download raw' button; export zoom now matches the on-screen view — contain the visible extent at the same scale (anchor width/height by aspect) across single / quad / Z+V exports.

Lowest-sweep-only: render just the lowest elevation cut(s) (LOW_SWEEP_TOL=0.15) so a site's 0.3 deg supplemental cut hides its 0.5 deg cut (e.g. KBUF). Applied to the xradar render path (_tree_to_frames) and the dealias path (_dealias_dtree). Server-side sweep selection.

Re-apply Py-ART elimination on stable base: xradar fork = sole ingest, dealias via region_dealias.sweep_folds on xradar arrays (Nyquist from ds['nyquist_velocity'], max|V| fallback), bundled nexrad_sites.py coords (replaces pyart NEXRAD_LOCATIONS), removed _process_pyart fallback, dropped arm-pyart. Server-side only — no live-default/UI changes (built on a4cbd62).

Cosmetic update on stable base: title -> 'NEXRAD Level 2 low level sweep browser', remove Py-ART processing credit (+ add (S. Nesbitt) to region-dealias), one consistent dvh map height + tighter mobile layout. Text/CSS only — no ingest/functional changes.

Remove debug instrumentation from app.py (revert thread-pool gate + breadcrumbs from abandoned Mac-app debugging)

macOS bundle: eliminate fork() — thread decode pool (NEXRAD_INPROC_POOL) + open browser via os.posix_spawn (Obj-C process aborts on fork)

Briefcase launcher: open browser via macOS /usr/bin/open (robust) + keep-alive marker

Briefcase: open app in default browser instead of pywebview (pyobjc segfaults in the thinned bundle); force fork for the decode pool; drop pywebview/pyobjc/proxy_tools

Briefcase: fix pywebview backtracking to 3.4 — ship proxy_tools wheel + --find-links, pin pywebview>=5, drop std-nslog (<private> log redaction)

Briefcase launcher: fix macOS-spawn worker imports (HERE on sys.path at import) + verbose startup logging + browser fallback if pywebview fails

Pin gradio==5.34.2 to match HF Space sdk_version (Space + Mac identical; avoids pip drift past sdk_version)

Pin gradio>=5,<6: app UI targets Gradio 5 (Gradio 6 dropped launch(show_api=...))

Student guide: state macOS Sonoma (14) or later as the requirement

Briefcase: min_os_version=14.0 for numpy-2-coherent stack (netCDF4 1.7.x arm64 wheel is macosx_14); add std-nslog; student install guide

Briefcase: min_os_version=12.0 (scipy/netCDF4 wheels need macOS 12+); document adhoc-sign distribution caveat

Briefcase: hyphenate app name (nexrad-l2) so module maps to src/nexrad_l2 package

Briefcase: PEP 639 SPDX license string (fixes 'briefcase create' license error)

Desktop: add Briefcase (BeeWare) build as an alternative to py2app

Desktop: free unsigned .app/.dmg build (Apple Silicon) — build_app.sh, icon, FIRST_OPEN instructions

Desktop: inherit deps from root requirements (single source); launcher interface check + sync docs

Guard background daemons under start_background() for macOS spawn-safety; add desktop launcher (pywebview)

Site picker: switch radar in place with progress bar (no full reload)

Site picker: use curated WSR-88D list (sites.py), not all NEXRAD_LOCATIONS (drops TDWR)

Add in-map radar-site picker overlay + block-I favicon

Live: server-side poller keeps recently-viewed sites' chunks fresh

Live: check the chunk feed for new scans every minute (Timer 120->60s)

Hide redundant top Field dropdown (use the in-map field selector)

Nudge map height offset 160->170 to fit footer (measured ideal ~169)

Full-bleed layout: override Gradio's 1280px centered main; 2px edges

Tighten layout: ~2px edges, collapse inter-element gaps, fill map

Use more of the window: compact header + fix map height offsets

Header: credit CliMAS / Univ. of Illinois (climas.illinois.edu)

Show the radar site ID in the page (tab) title

Dealias: keep the current frame instead of resetting

Live autoupdate: never grey the display

Warnings: add flash flood warnings (FF) as green polygons

Log active dealias engine at startup (greppable in Space logs)

Progress bar: label the active dealiaser (Rust region-dealias vs Py-ART)

Footer: credit the Rust region-dealias dealiaser

Enable region-dealias (Rust dealiaser) now that it's on PyPI

Use region-dealias (Rust) for dealiasing, with pyart fallback

Export: add units to the quad/Z+V mini colorbars

Fix shared Z+V link: add ZVF to field dropdown choices

Share link: always build an absolute URL

Force-refresh: stop spinner as soon as server reports done

Live: add forced-refresh button (snappy, in-place)

Loop: dwell on last frame 4x the frame interval

Warning polygons: 0.25pt black buffer (casing)