SkySight layers & regions — integration investigation

Status: verified against the live service on 2026-08-26 (the owner’s account, region EUROPE/ICOND2, via the logged-in web app at https://skysight.io/secure/, its JS bundle assets/main-D0tYFImc.js, the page global window.params, and unauthenticated curl probes of the tile endpoints). Written as the hand-off for the implementation pass on the SkySight layer picker.

0. TL;DR

• The app’s picker is server-driven: it lists whatever GET /api/layers?region_id=… returns (+ a synthetic satellite). Only the grouping/ordering is hard-coded (§2). The website no longer calls /api/regions or /api/layers at all — its catalogue is compiled into the bundle (regions) and a page global params (layers) — so the app-facing API and the website can drift; the tile probes below are the ground truth.
• Dead on the server (still in the app’s tables): tcc, sunlight, sfctemp, w_8000, w_9000, pfdtotclub, bom_rain (EUROPE), and the separate …/bsratio/ tile URL. The picker only shows what the API returns, so these matter mainly for the special-case code, but tcc is worth checking in the app: the site renders “Cloud Cover” from CFRACL.
• New on the server, reachable as vector tiles today (drop-in for the existing fill-layer path): uv_10 (surface wind, replaces sfcwind0), zsfclclmask_low, sigwx (significant weather), potfd_as (airspace-aware XC speed), oktas_cu, CFRACL (also carries CFRACM/ CFRACH as source-layers).
• New, composite (webp raster) only: t2c, sfcdewpt, bltopwind, thermalwave, mslpress, freezing, cceil, ctops, vfr, visibility, turbulence_low/mid/high, densityaltitude, ice_base, ice_top, carb_icing, ridge, wind-at-altitude uv_{alt}. These are blocked on Mapbox v11: the tiles carry raw values in the red channel, not colours, and v6 cannot run a colour ramp over a raster (§5).
• edge.skysight.io vector tiles require Origin: https://skysight.io (400 without). The URLSession swizzle in the app is load-bearing.
• Regions: 19 in the catalogue; the ICON family is now ICON, ICONEU, ICOND2 (new, high-res Europe). The app excludes ICON/ICONEU by id, so ICOND2 would pass through — its layers are composite-only (§5), which the current vector-fill code cannot draw.

1. Where the app’s layers come from (unchanged)

Step	Code	Notes
Sign in	POST https://skysight.io/api/auth, header X-API-KEY: Vulture, body {username, password}	SkySightAuthenticationRequest; response SkySightUserAuthInfo { key, allowed_regions }
Regions	GET /api/regions with X-API-KEY: <key>	[SkySightRegion { id, name, tz }]
Layers	GET /api/layers?region_id=<id>	[SkySightLayer { id, name, description?, legend? }], legend = { unit_type, colors: [{ name, value, color:[r,g,b] }] }
Synthetic	SkySightLayer.satellite	appended by SkySightLayersViewModel to every region

Both endpoints answer 401 {"message": "Bad API Key"} without the key, so their live payloads could not be captured in this session (the website does not call them; see §10 for how to capture them from the app). Regions and per-region layers are disk-cached for 7 days (SkySightManager, skysight-regions.cache, skysight-layers.cache); a server-side change is invisible until the weekly invalidation.

Key files:

• Modules/App/Sources/Components/SkySight/SkySightManager.swift — auth, regions, layers, caches, allowedRegions(for:).
• Modules/App/Sources/Components/SkySight/Request/* — the three requests; URLSession+Origin.swift injects the Origin header.
• Packages/Scenes/Sources/Scenes/Screens/SkySight/Models/* — value types; SkySightLayer.swift — sections + ordering.
• Modules/App/Sources/Components/SkySight/Extensions/SkySightOverlay+Tile.swift — every tile URL and per-layer special case.
• Modules/App/Sources/Modules/Detail Map/MapViewDataSource+Weather.swift — how the overlay is put on the map.

2. What the app hard-codes (grouping, ordering, special cases)

Grouping/ordering (SkySightLayer.sectionKey, [SkySightLayer].reorder()):

Section	Layer ids, in display order	Server status 2026-08-26
Thermals	pfdtot, potfd, wstar_bsratio, hwcrit, dwcrit, stars	all live
Clouds	satellite, tcc, zsfclcldif, zsfclclmask, zblclmask, cape, accrain, CFRACM, CFRACH, sunlight, sfctemp, sfcdewpt	tcc, sunlight, sfctemp dead; sfcdewpt composite-only
Wind	ridge, sfcwind0, blwind, wblmaxmin	ridge composite-only; sfcwind0 still served but superseded by uv_10
Wave	w_1000 … w_9000	w_1000–w_7000 live; w_8000, w_9000 dead
Experimental	freezing, cceil	composite-only
Others	anything else, unsorted	—

Ids referenced elsewhere in the app but missing from the section table: CFRACL (in the ordering list only — lands in Others while CFRACM/CFRACH sit in Clouds), pfdtotclub and bom_rain (spread/legend special cases; both dead on EUROPE), bsratio (companion overlay, see §5).

Per-layer special behaviour in SkySightOverlay+Tile.swift / MapViewDataSource+Weather.swift:

Layer id(s)	App behaviour	Live finding
satellite	Raster satellite.skysight.io/tiles/{z}/{x}/{y}@2x?date=YYYY/MM/DD/HHmm&mtg=true (10-min steps, max zoom 7) + rain radar /radar/… at 0.6 opacity; date capped at today; period → UTC using TimeZone.current	Site uses the identical tiles and radar builders, plus a new /lightning/{z}/{x}/{y}@2x?date=… vector source (source-layer lightning, z0–4).
pfdtot	Period forced to 1800; period stepping disabled; hard-coded 10-stop legend (50–950)	Confirmed: pfdtot only exists at 1800 (204 at other hours); site legend is 10 stops 50 … >950. The site palette differs from the app’s (§7).
pfdtot, pfdtotclub, bom_rain	Spread markers from cloudfunctions.net/tile?query=spread&region=GFS&hour=1500	Site fetches spread from https://edge.skysight.io/GFS/{YYYYMMDD}/{HHmm UTC}/spread/{z}/{x}/{y} (z1–6, source-layer spread, question icon by spread attribute), only when the PFD “Uncertainty” toggle is on, and at the selected hour (not fixed 1500). The cloudfunctions URL still answers 200.
wstar_bsratio	Companion fill from edge…/{period}/bsratio/{z}/{x}/{y}, patterns bs_{idx}	That URL returns 204 (empty). The stipple lives inside the wstar_bsratio tile as source-layer bsratio (verified in the tile bytes: layers 1400, 1400_extra, bsratio; keys idx, conditions, src). Same tile, second style layer.
hwcrit, dwcrit, zsfclclmask on EUROPE/ICON*	Legend cut at value 2400 and colours rescaled	Site: for those regions it sets min = step = 200 for hwcrit/dwcrit/cucloudfrac and step = 200 for zsfclclmask, i.e. legend 200 … >2600 (13 stops) and everything above clamps to the top colour — no rescaling (§7).
all other layers	Vector edge.skysight.io/{region}/{YYYYMMDD}/{HHmm}/{layer}/{z}/{x}/{y}, source-layer = period, colour = legend.colors[idx], zoom 0–5	Same URL shape; site uses minzoom 3, maxzoom 5 (ALPS 6), and additionally draws the tile’s {HHmm}_extra source-layer as a symbol layer (icon cc7 where feature z ≤ zoom: condition markers).
wind arrows	cloudfunctions.net/tile?query=wind&region&date&hour&alt=0…9, label alt × 600 m	Still answers 200, but the site no longer uses it: barbs/arrows are GPU-rendered from composite uv_{alt} webp tiles (§6).

Periods are hard-coded 0800–2000 half-hourly (String.rawPeriods), default 1400; forecast dates unrestricted.

3. Regions — verified

The website ships a static catalogue (const Mr in the bundle). The user never picks a region: the map auto-selects from the viewport (setRegionFromBounds), with only a “SkySight ⇄ ICON” toggle (Europe: EUROPE /ALPS vs ICONEU/ICOND2, chosen by bounds + zoom; ALPS only when zoomed past 5.5 within a day). Per-account entitlement is not visible on the website (the JWT carries region: EUROPE, paid, aircraft only); the app’s allowed_regions from /api/auth remains the only entitlement source and was not re-verified.

id	name	model_family	tz (tile hour base)	category	notes
GFS	Global - NOAA	noaa	UTC	Global	no polygon, global bbox
ICON	DWD-ICON Global	dwd	UTC	Global	composite selector ICONCH1; vector maxzoom 4
ICONEU	Europe-ICONEU	dwd	UTC	Europe
ICOND2	ICOND2	dwd	UTC	Europe	new; polygon ≈ D-A-CH-NL-BE-DK
EUROPE	Central Europe	ss	Europe/Warsaw	Europe
ALPS	Alps	ss	Europe/Berlin	Europe	vector maxzoom 6
MIDDLE_EAST	Middle East	ss	Asia/Jerusalem	Asia
INDOCHINA	Indochina	ss	Asia/Bangkok	Asia
JAPAN	Japan	ss	Asia/Tokyo	Asia
SANEW	South Africa	ss	Africa/Johannesburg	Africa
EAST_AUS	East Australia	ss	Australia/NSW	Oceania	obs stations
WA	West Australia	ss	Australia/Perth	Oceania	obs stations
NZ	New Zealand	ss	Pacific/Auckland	Oceania
BRAZIL	Brazil	ss	America/Sao_Paulo	South America
ARGENTINA_CHILE	Argentina/Chile	ss	America/Argentina/Buenos_Aires	South America	wave range −3.25…5.75
EAST_US	US/Canada East	ss	America/New_York	North America
WEST_US	US/Canada West	ss	America/Los_Angeles	North America
HRRR	HRRR	hrrr	America/Los_Angeles	North America	composite for b7 layers
HRRRAK	Alaska	hrrr	Pacific/Samoa	North America

Region facts that affect the app:

• Hourly regions: ICON, ICONEU, ICOND2, HRRR, HRRRAK step 3600 s; every ss/noaa region steps 1800 s. The app’s half-hourly period wheel would request non-existent half hours on DWD/HRRR regions.
• Region time zone drives the tile hour: the site formats the vector path’s HHmm in the region’s tz (so ICOND2 paths are in UTC, EUROPE in Europe/Warsaw). The app passes the picked period through unchanged and labels it with the region tz — consistent, as long as the API’s tz matches the catalogue above.
• Composite (webp) paths use UTC for both date and hour, unlike the vector paths.
• The app’s hard-coded exclusion of ICON/ICONEU does not cover ICOND2.

4. Layer catalogue — verified (window.params + sidebar)

params[id] = { name, type, unit, min, max, step, aircraft, models }. type ∈ vert | hgt | spd | temp | dist | xcspd | "" drives unit conversion (the app’s SkySightLegend.unitType uses the same spd/vert/ hgt vocabulary). models lists the model families the layer exists for (ss, noaa, hrrr, dwd, cosmo), which is the per-region availability rule (region → model_family in §3). aircraft: G glider, P paraglider, H hang glider, B balloon, A plane, M model aircraft.

Glider sidebar as rendered for EUROPE (Dutch UI → id; ✱ = hidden on ICON*/HRRR* regions, † = only on NZ, JAPAN, ARGENTINA_CHILE, ICON*, EUROPE, ALPS):

Site group	Item → id	type / unit / range	models
Thermals	Potential Flight Distance → pfdtot (+ spread uncertainty)	dist km 50–950/100	ss, hrrr, dwd
	XC Speed → potfd (potfd_as when airspace on)	xcspd kph 40–160/10	ss, hrrr, dwd, noaa
	Thermal Strength & B/S → wstar_bsratio (+ bsratio source-layer)	vert m/s 0.5–4/0.5	ss, noaa, hrrr, dwd
	Height of Thermals → hwcrit	hgt m 300–4800/300	ss, noaa, hrrr, dwd
	Depth of Thermals (AGL) → dwcrit	hgt m 300–3600/300	ss, noaa, hrrr, dwd
	Significant Weather → dwcrit + sigwx	—	—
Clouds	Cu Overview ✱ → cucloudfrac (rendered from the hwcrit tile)	hgt m 300–4800/300	ss, noaa, hrrr, dwd
	Cu Depth → zsfclcldif	hgt m −1000–700/100	ss, noaa, hrrr, dwd
	Cu Cloudbase → zsfclclmask + zsfclclmask_low	hgt m 0–4800/300	ss, noaa, hrrr, dwd
	Cu Coverage ✱ → oktas_cu	% 0–100/12.5	ss, noaa, hrrr, dwd
	Cloud Cover → CFRACL tile, source-layers {HHmm}, CFRACM, CFRACH	% 5–95/15	ss, noaa, hrrr, dwd
	CAPE / Storms → cape	J 100–3100/300	ss, noaa, hrrr, dwd
	Rain → accrain	mm 0–5/0.5 (last half hour)	ss, noaa, hrrr, dwd
Wind	Off / Barbs / Arrows / Particles (overlay on any layer)	—	—
	Wind at {alt} → uv_{alt} composite, alt ∈ §6 list	spd	—
	Surface Wind → uv_10	spd m/s 0–12/1	ss, noaa, hrrr, dwd
	Thermal Layer Wind (Avg) → blwind	spd m/s 1–16/1	ss, noaa, hrrr, dwd
	Thermal Top Wind → bltopwind	spd m/s 1–19/1	ss, noaa, hrrr, dwd
	Convergence → wblmaxmin	vert m/s −0.25–0.75/0.1	ss, hrrr, cosmo
	Ridge Lift → ridge	vert m/s 0.1–1.2/0.1	ss, hrrr, cosmo
	Valley Winds † → uv_10 filtered	—	—
Wave (dropdown)	Wave X-section, Thermal Wave → thermalwave, Vertical Velocity 1000…7000 m → w_1000…w_7000, 3D Wave	vert m/s −2.6–4.6/0.4	ss, hrrr, cosmo
General	Glide Range (tool), Terrain Relief (basemap)	—	—
	Last 72h Rainfall → bom_rain	mm 0–45/3	(Australia only in practice)
	Surface Temperature → t2c	temp °C −6–48/2	ss, noaa, hrrr, dwd
	Surface Dewpoint → sfcdewpt	temp °C −16–20/1	ss, noaa, hrrr, dwd
	MSL Pressure → mslpress	mBar 984–1034/2	ss, noaa, hrrr, dwd
	Low/Mid/High level cloud cover → CFRACL/CFRACM/CFRACH	% 5–95/15	ss, noaa, hrrr, dwd
	Thermal Hotspots → thermals (kk7 data)	—	—
	Freezing Level ✱ → freezing	hgt m 300–5700/300	ss, hrrr
	Density Altitude (Surface) → densityaltitude	hgt m 300–4800/300	ss, noaa, hrrr, dwd
	Overdevelopment → zblclmask	% 5–95/10	ss, hrrr, dwd
	Smoke → smoke	mg/m² 25–350/25	hrrr
Plane-only (not in glider menu)	vfr, turbulence_low/mid/high, visibility, cceil, ctops, ice_base, ice_top, carb_icing	—	ss (icing also hrrr)

Also in params but not in a glider menu: stars (0.5–5.5, PG/HG/model star rating), pfdtothg/potfd_hg (PG/HG variants), w_*_combo, w_9000 (listed but 404 on every endpoint), U/V/blwindU/blwindV (wind components), windataltitude.

5. Tile endpoints — verified

Rendering rule from the bundle (op(id, region)):

composite (webp raster)  if id starts with "w_"
                         or id ∈ y7 = {carb_icing, cceil, ctops, densityaltitude, freezing,
                                       ice_base, ice_top, t2c, sfcdewpt, sfcwind0,
                                       turbulence_low/mid/high, uv_10, vfr, visibility,
                                       blwind, bltopwind, wblmaxmin, ridge, mslpress, thermalwave}
                         or (region.target ∈ {ICON, ICONEU, ICOND2, HRRR}
                             and id ∈ b7 = {CFRACL, CFRACM, CFRACH, hwcrit, oktas_cu, pfdtothg,
                                            potfd, potfd_as, potfd_hg, potfd_hg_as, smoke,
                                            stars, wstar_bsratio, zblclmask})
vector (edge MVT)        otherwise
PFD (pfdtot)             composite on the ICON/HRRR targets, vector elsewhere

URL shapes (all verified 200 with curl):

Kind	Template	Auth	Zoom
Vector	https://edge.skysight.io/{target}/{YYYYMMDD}/{HHmm region-local}/{id}/{z}/{x}/{y}	needs Origin: https://skysight.io (400 otherwise); gzip MVT	3–5 (ALPS 6; PFD on ICON/GFS 4; wave on ICONEU/ICOND2 6)
Composite	https://cf.skysight.io/{composite|composite-ss}/{YYYYMMDD UTC}/{HHmm UTC}/{id}/{z}/{x}/{y}.webp (composite-ss for ss regions, composite for others, ICONCH1 for global ICON)	none	3–7 (ICON 4; ridge/uv_10 on ss: 9)
Composite, legacy form	https://cf.skysight.io/tile/{target}/{YYYYMMDD}/{HHmm}/{id}/{z}/{x}/{y}.webp	none
Spread	https://edge.skysight.io/GFS/{YYYYMMDD}/{HHmm UTC}/spread/{z}/{x}/{y}	Origin	1–6
Freshness	https://cf.skysight.io/tile/updated/{target}/{YYYYMMDD}/{HHmm} → {"unix":"1787744469","init":""}	none
Satellite	https://satellite.skysight.io/tiles/{z}/{x}/{y}@2x?date=YYYY/MM/DD/HHmm&mtg=true (raster, max 8)	none
Radar	https://satellite.skysight.io/radar/{z}/{x}/{y}@2x?date=… (raster 512)	none
Lightning	https://satellite.skysight.io/lightning/{z}/{x}/{y}@2x?date=… (vector, source-layer lightning)	none	0–4
Observations	https://edge.skysight.io/stations/{YYYYMMDD/HHmm}/{z}/{x}/{y} (vector, source-layer stations)	Origin	4–12
Legacy wind	https://us-central1-skysight-1260.cloudfunctions.net/tile?query=wind&region&date&hour&alt	none	still 200

Composite tiles are data, not pictures — and that blocks them on Mapbox v6

Verified by decoding the tiles (2026-08-26). A composite webp carries the forecast value in the pixel’s red channel, scaled linearly across the layer’s [min, max] from params; green and blue are zero and alpha is the mask. Decoding composite-ss/20260826/1400/t2c/4/8/5.webp against t2c’s range of −6…48 °C gives a median of 24 °C and a 1–99 % span of 15–32 °C — a European August afternoon. The same for freezing over 300…5700 m gives a median of 3646 m. Layers with two components (thermalwave) also use blue and a graded alpha.

So the site is not downloading coloured maps: it downloads numbers and colours them in a shader (dataType: "scalar", scale, valueChannel, maskAbove/maskBelow). Dropping a composite URL into an MGLRasterTileSource would paint a black-to-red gradient, not a forecast.

Consequence: every composite-only layer is blocked on the Mapbox v11 migration. Mapbox v6 has no way to run a colour ramp over a raster. v11 does, declaratively — raster-color with a colour-ramp expression, raster-color-mix to select the red channel ([1, 0, 0, 0]), and raster-color-range set to the layer’s [min, max]. That is the same three pieces of information params already gives us, so the work at v11 time is a table of ranges plus one style layer, not a shader project.

Until then the app can only draw the vector layers, which is why the DWD (ICON) family is excluded from the region list (§8.D): most of its layers are composite-only.

Serving matrix, tile 4/8/5 (EUROPE) at 1400 on 2026-08-26 (200 served, 204/404 nothing). edge = vector EUROPE, ss = composite-ss, D2 = composite for ICOND2:

id              edge  ss   D2 | id              edge  ss   D2 | id              edge  ss   D2
pfdtot(1800)    200  404  200 | CFRACL          200  200  200 | w_1000..w_7000  200  200  200
potfd           200  200  200 | CFRACM/H        200  200  200 | w_8000, w_9000  204  404  404
potfd_as        200  200  200 | sunlight        204  404  404 | freezing        204  200  404
wstar_bsratio   200  200  200 | sfctemp         204  404  404 | cceil, ctops    204  200  404
hwcrit          200  200  200 | t2c             204  200  200 | vfr, visibility 204  200  404
dwcrit          200  200  200 | sfcdewpt        204  200  200 | turbulence_*    204  200  404
stars           200  200  200 | ridge           204  404  200 | densityaltitude 204  200  404
tcc             204  404  404 | sfcwind0        200  200  404 | ice_base/top    204  200  404
zsfclcldif      200  200  200 | uv_10           200  200  200 | carb_icing      204  200  404
zsfclclmask     200  200  200 | blwind          200  200  200 | oktas_cu        200  200  200
zsfclclmask_low 200  404  404 | bltopwind       204  200  200 | cucloudfrac     204  404  404
zblclmask       200  200  200 | wblmaxmin       200  200  200 | smoke           204  404  404
cape, accrain   200  200  200 | thermalwave     204  200  200 | bsratio (URL)   204  404  404
mslpress        204  200  200 | pfdtotclub      204  404  404 | bom_rain        204  404  404

(ridge 404 on composite-ss at z4 may just be zoom — the site gives it maxzoom 9; re-probe at z6+ before concluding.)

6. Time, horizon, wind and wave — verified

• Slider: 08:00–20:00 in the user’s zone (06:00 start for balloons), step 1800 s on ss/noaa regions, 3600 s on ICON*/HRRR*. Tiles are actually served from 06:00 to 20:00 (EUROPE hwcrit: 0600–2000 → 200; 2030+ → 204).
• Horizon: EUROPE pfdtot served for today + 5 days (0826–0831; 0901 → 204) and past days are still served (0825, 0820 → 200). ICOND2 composite reached only +1 day at probe time.
• updated endpoint gives the model run timestamp per target/date/hour — useful for an “Updated: 13:38” chip like the site’s.
• Wind overlay (any layer): types off / barbs / arrows / particles. Altitude options for ss regions: 120, 240, 360, 480, 600, 720, 840, 960, 1080, 1200, 1320, 1440, 1560, 1680, 1800, 2100, 2400, 2700, 3000, 3300, 3600, 4200, 4800 m (others: 600 → 4800 by 300). Data: composite uv_{alt} webp (uv_600 observed) — not the cloudfunctions alt=0…9 index the app uses, although that endpoint still answers.
• Wave: w_1000 … w_7000 for gliders (ss/hrrr/cosmo models only — none on DWD regions); vector and composite exist, the site draws composite. The ICON toggle hides the Wave group entirely.

7. Legends — verified

• pfdtot on the site: labels 50, 150 … 850, >950, colours rgb(0,0,143) (0,68,255) (0,248,255) (5,203,92) (104,208,9) (255,247,0) (255,180,0) (255,75,0) (213,0,35) (94,0,131). The app’s hard-coded override (commit 8be1e4a13) uses a different, muted palette ([110,100,190] … [155,55,140]). Decide which is wanted; the ten-stop structure matches.
• hwcrit on EUROPE: labels 200, 400 … 2400, >2600, colours rgb(0,0,143) (0,23,255) (0,158,255) (0,244,219) (5,203,92) (60,195,12) (191,236,4) (255,230,0) (255,180,0) (255,104,0) (255,17,0) (183,0,59) (94,0,131), with indices ≥ 12 clamped to the last colour. The app instead truncates the API legend at "2400" and rescales the colours — a different look; consider mirroring the site (clamp, don’t rescale).
• Unit conversion on the site: type from params (hgt/spd/vert/ temp/dist/xcspd) with the user’s units; matches the app’s unit_type handling for the three it knows, but the app has no temp, dist, xcspd cases (falls back to the stop name).
• Layers with no numeric legend on the site (AC set): carb_icing, turbulence_*, vfr (categorical), thermalwave (Likely…Nil).

8. Gap analysis for the app

A. Fix in the current vector path (small, no new rendering):

1. CFRACL → Clouds section (sectionKey), and add the new vector ids to the section table so they don’t land in Others: uv_10 (Wind), potfd_as (Thermals), oktas_cu (Clouds), zsfclclmask_low (Clouds), sigwx (Thermals/Experimental), stars already there.
2. B/S ratio stipple: read source-layer bsratio from the existing wstar_bsratio source instead of the dead /bsratio/ request.
3. _extra symbol layer (condition markers, icon cc7 where z ≤ zoom) — optional parity item; needs the cc7 sprite.
4. Cloud Cover: if the API still returns tcc, its tiles are empty; render “Cloud Cover” from CFRACL with the three source-layers, or drop tcc from the sections (it will still be listed if the API sends it).
5. Half-hour periods on DWD/HRRR regions request non-existent tiles — gate the period list on the region (hourly for ICON*/HRRR*), and consider exposing 06:00–07:30 which the server serves.
6. Spread markers: switch to edge.skysight.io/GFS/…/spread at the selected UTC hour (the app hard-codes 1500 and the cloudfunctions host) and tie them to an “Uncertainty” toggle as the site does.
7. Drop w_8000/w_9000, sunlight, sfctemp, pfdtotclub, bom_rain from the tables (or leave — harmless if the API stops sending them).
8. reorder() comparator is not a strict weak ordering (unknown ids sort unpredictably); satellite period → UTC uses TimeZone.current instead of the region tz.

B. Blocked on Mapbox v11 — the composite layers: t2c, sfcdewpt, bltopwind, thermalwave, mslpress, freezing, cceil, ctops, densityaltitude, ridge, the plane-only set, and most layers on the DWD regions. The tiles are value-encoded (§5), so they need a raster colour ramp, which arrives with v11: raster-color over the layer’s range, raster-color-mix [1, 0, 0, 0] to read the red channel, and raster-color-range from params’s min/max. Carry the ranges from §4 into a table at that point. Nothing to do before the migration.

C. Wind overlay: keep the cloudfunctions barbs (still served) or move to uv_{alt} composites — the latter needs value decoding, so it is a v11-era item, not a picker change.

D. Region handling: ICOND2 is now excluded alongside ICON/ICONEU (done 2026-08-26) — most of the family’s layers are composite-only, so the region came up half blank. Lift the exclusion when B lands. Read per-region availability from the /api/layers response rather than assuming EUROPE’s list.

Everything added must also extend the Docs/mapbox-v11-feature-checklist.md row “SkySight overlay + rain/wind/spread/conditions layers, legend”.

9. Known issues found while reading (independent of the live check)

• CFRACL missing from sectionKey (§2).
• reorder() comparator is not a strict weak ordering (§8.A.8).
• Satellite period → UTC uses TimeZone.current instead of the region’s zone.
• Spread markers always query hour 1500 (§8.A.6).
• Layer/region caches live 7 days with no manual refresh.
• allowedRegions(for:) excludes ICON/ICONEU but not ICOND2.

10. How this was verified / how to re-verify

• Website: https://skysight.io/secure/ (Vue 3 + Pinia + MapLibre). Useful page globals: skysightMap (MapLibre map — getStyle().sources/layers gives every live tile URL), params (layer catalogue), user (profile; contains the backend JWT — never copy it). Pinia stores via document.querySelector('#app').__vue_app__.config.globalProperties.$pinia (region, clock step/min/max, wind-at-altitude altitudeOptions).
• Bundle: https://skysight.io/secure/assets/main-D0tYFImc.js (served gzip; curl --compressed). Region catalogue const Mr={…}; layer sets y7/b7/A7/C7; URL builders mn (vector), L1/L7 (composite), O1 (spread), D9 (updated), IR/LR/kR (satellite/radar/lightning).
• Tiles: curl -H 'Origin: https://skysight.io' <edge url>; composite and updated need no headers. 204 = no data for that id/time/tile.
• Still unverified: the live /api/regions and /api/layers payloads and this account’s allowed_regions. Capture them from the app (a breakpoint in SkySightManager.fetchRegions/fetchLayers, or Charles/Proxyman on the device) and diff the ids against §4/§5.