{
 "generated_utc": "2026-08-24T05:26:51Z",
 "gfs_cycle_utc": "2026-08-24T00:00:00Z",
 "model": {
  "source": "NCEP GFS 0.50 degree",
  "vertical_coordinate": "constant density (isopycnic)",
  "horizon_hours": 449.5,
  "output_interval_min": 30,
  "integration_step_s": 900,
  "wind_field_interval_h": 3
 },
 "staleness": {
  "fresh_seed_max_h": 24.0,
  "served_until_h": 336.0,
  "track_max_age_h": 72.0,
  "region_spread_deg": 60.0,
  "note": "A trajectory is served for 336 h after the last real fix and then the flight disappears. That matches the archive's own bridging limit: 23% of flights go quiet for over a week and are then heard again, so a shorter window drops balloons that are still flying. Past dead_reckoned flights the balloon has not been heard from since seed_time, so its present position is a prediction too -- the silent period is reconstructed from GFS analyses of weather that has already happened, which is why wind_source distinguishes analysis from forecast. Use display_as, not seed_age_h, to decide how to draw a flight: 'track' means the members still agree and a line is meaningful, 'region' means draw the member envelope instead because the nominal member is no better than any other."
 },
 "members": {
  "offsets_m": [
   -2000,
   -1500,
   -1000,
   -500,
   0,
   500,
   1000,
   1500,
   2000
  ],
  "nominal_offset_m": 0,
  "note": "Each member is seeded at the last observed altitude plus its offset and then conserves the density it started with. The ladder is a sensitivity fan, not a probability distribution: adjacent members diverge by roughly 1,200 km over seven days. levels_spanned reports how many GFS levels the fan actually straddles, usually 2 or 3."
 },
 "files": {
  "trajectories_csv_gz": "PBA_forecast_20260824_00Z.csv.gz",
  "trajectories_geojson_gz": "PBA_forecast_20260824_00Z.geojson.gz"
 },
 "counts": {
  "flights": 22,
  "members": 9,
  "rows": 89226
 },
 "flights": [
  {
   "callsign": "AG6NS-23",
   "flight_id": "AG6NS-23_2026-02-07",
   "payload_type": "WSPR",
   "seed_time": "2026-08-22 13:43:40",
   "seed_lat": -61.64583,
   "seed_lon": 25.04168,
   "seed_alt_m": 12480.0,
   "seed_age_h": 39.61,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 23:45:00",
    "lat": -51.73172,
    "lon": 120.1184,
    "alt_m": 12384.8
   },
   "member_spread_deg": {
    "lat": 12.89,
    "lon": 221.42
   },
   "member_spread_now_deg": {
    "lat": 11.31,
    "lon": 48.91
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS53",
   "flight_id": "BSS53_2026-03-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-24 03:51:18",
   "seed_lat": 77.89583,
   "seed_lon": -66.75,
   "seed_alt_m": 12290.0,
   "seed_age_h": 1.48,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-31 03:15:00",
    "lat": 58.18398,
    "lon": 53.28097,
    "alt_m": 12552.0
   },
   "member_spread_deg": {
    "lat": 26.16,
    "lon": 105.4
   },
   "member_spread_now_deg": {
    "lat": 0.13,
    "lon": 0.5
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS54",
   "flight_id": "BSS54_2026-07-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 22:48:48",
   "seed_lat": 48.33333,
   "seed_lon": -72.91667,
   "seed_alt_m": 13800.0,
   "seed_age_h": 6.52,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 23:45:00",
    "lat": 48.11693,
    "lon": 148.72135,
    "alt_m": 13875.1
   },
   "member_spread_deg": {
    "lat": 8.57,
    "lon": 132.26
   },
   "member_spread_now_deg": {
    "lat": 4.18,
    "lon": 5.39
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-23",
   "flight_id": "DG2GG-23_2026-05-23",
   "payload_type": "WSPR",
   "seed_time": "2026-08-24 00:34:00",
   "seed_lat": 32.5,
   "seed_lon": -121.04167,
   "seed_alt_m": 12920.0,
   "seed_age_h": 4.77,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-31 00:00:00",
    "lat": 66.64443,
    "lon": 27.91245,
    "alt_m": 12575.6
   },
   "member_spread_deg": {
    "lat": 31.83,
    "lon": 81.18
   },
   "member_spread_now_deg": {
    "lat": 0.57,
    "lon": 0.49
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-30",
   "flight_id": "DG2GG-30_2026-08-07",
   "payload_type": "WSPR",
   "seed_time": "2026-08-24 00:46:00",
   "seed_lat": 48.52083,
   "seed_lon": 114.5,
   "seed_alt_m": 12470.0,
   "seed_age_h": 4.57,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-31 00:15:00",
    "lat": 55.58729,
    "lon": -108.50517,
    "alt_m": 12713.2
   },
   "member_spread_deg": {
    "lat": 24.46,
    "lon": 122.86
   },
   "member_spread_now_deg": {
    "lat": 1.83,
    "lon": 1.17
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-31",
   "flight_id": "DG2GG-31_2026-08-13",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 23:47:00",
   "seed_lat": 40.66667,
   "seed_lon": -147.58333,
   "seed_alt_m": 13300.0,
   "seed_age_h": 5.55,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 23:45:00",
    "lat": 48.26642,
    "lon": -14.15531,
    "alt_m": 13020.8
   },
   "member_spread_deg": {
    "lat": 19.48,
    "lon": 59.81
   },
   "member_spread_now_deg": {
    "lat": 1.12,
    "lon": 1.6
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DN3LEO-13",
   "flight_id": "DN3LEO-13_2026-04-12",
   "payload_type": "WSPR",
   "seed_time": "2026-08-24 02:23:00",
   "seed_lat": 72.83333,
   "seed_lon": -139.66667,
   "seed_alt_m": 11840.0,
   "seed_age_h": 2.95,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-31 02:00:00",
    "lat": 79.32345,
    "lon": 164.41711,
    "alt_m": 11745.6
   },
   "member_spread_deg": {
    "lat": 29.08,
    "lon": 246.32
   },
   "member_spread_now_deg": {
    "lat": 1.26,
    "lon": 1.61
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "EI6BFW-18",
   "flight_id": "EI6BFW-18_2026-07-25",
   "payload_type": "WSPR",
   "seed_time": "2026-08-22 15:53:00",
   "seed_lat": 53.35417,
   "seed_lon": 17.375,
   "seed_alt_m": 12510.0,
   "seed_age_h": 37.45,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 23:30:00",
    "lat": 50.90112,
    "lon": 129.77392,
    "alt_m": 12819.2
   },
   "member_spread_deg": {
    "lat": 32.4,
    "lon": 328.43
   },
   "member_spread_now_deg": {
    "lat": 10.98,
    "lon": 24.97
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "K5NOT-11",
   "flight_id": "K5NOT-11_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 20:50:37",
   "seed_lat": 40.97911,
   "seed_lon": -75.41666,
   "seed_alt_m": 13300.0,
   "seed_age_h": 200.49,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 23:45:00",
    "lat": 20.24582,
    "lon": -70.7927,
    "alt_m": 13402.2
   },
   "member_spread_deg": {
    "lat": 43.59,
    "lon": 251.4
   },
   "member_spread_now_deg": {
    "lat": 23.4,
    "lon": 90.12
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "KC3LBR-449",
   "flight_id": "KC3LBR-449_2026-07-06",
   "payload_type": "WSPR",
   "seed_time": "2026-08-24 04:33:49",
   "seed_lat": 54.95833,
   "seed_lon": 154.16667,
   "seed_alt_m": 13250.0,
   "seed_age_h": 0.77,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-31 04:30:00",
    "lat": 56.79412,
    "lon": -86.85851,
    "alt_m": 13390.9
   },
   "member_spread_deg": {
    "lat": 34.65,
    "lon": 189.04
   },
   "member_spread_now_deg": {
    "lat": 0.1,
    "lon": 1.44
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KC5TRB-1",
   "flight_id": "KC5TRB-1_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-12 11:40:43",
   "seed_lat": 57.39578,
   "seed_lon": 26.00003,
   "seed_alt_m": 12570.0,
   "seed_age_h": 281.66,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 23:45:00",
    "lat": 56.71743,
    "lon": 167.50113,
    "alt_m": 12673.1
   },
   "member_spread_deg": {
    "lat": 30.62,
    "lon": 298.62
   },
   "member_spread_now_deg": {
    "lat": 27.9,
    "lon": 309.94
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "KC7RW-3",
   "flight_id": "KC7RW-3_2026-08-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 16:54:00",
   "seed_lat": 33.3125,
   "seed_lon": -26.5,
   "seed_alt_m": 12770.0,
   "seed_age_h": 12.43,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 23:30:00",
    "lat": 44.83648,
    "lon": 141.87496,
    "alt_m": 12433.0
   },
   "member_spread_deg": {
    "lat": 17.53,
    "lon": 177.8
   },
   "member_spread_now_deg": {
    "lat": 1.59,
    "lon": 1.63
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KD7FXO-1",
   "flight_id": "KD7FXO-1_2026-08-02",
   "payload_type": "WSPR",
   "seed_time": "2026-08-24 04:20:00",
   "seed_lat": 22.60417,
   "seed_lon": -175.375,
   "seed_alt_m": 13080.0,
   "seed_age_h": 1.0,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-31 03:45:00",
    "lat": 29.51637,
    "lon": -35.43653,
    "alt_m": 13206.7
   },
   "member_spread_deg": {
    "lat": 19.71,
    "lon": 97.2
   },
   "member_spread_now_deg": {
    "lat": 0.12,
    "lon": 0.2
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KE8RES-8",
   "flight_id": "KE8RES-8_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 23:01:00",
   "seed_lat": 73.33333,
   "seed_lon": -150.25,
   "seed_alt_m": 11900.0,
   "seed_age_h": 6.32,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-30 23:30:00",
    "lat": 67.94313,
    "lon": 166.77103,
    "alt_m": 12162.8
   },
   "member_spread_deg": {
    "lat": 24.06,
    "lon": 199.42
   },
   "member_spread_now_deg": {
    "lat": 1.29,
    "lon": 3.07
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KE9DAB-11",
   "flight_id": "KE9DAB-11_2026-07-29",
   "payload_type": "WSPR",
   "seed_time": "2026-08-13 21:11:00",
   "seed_lat": 63.66667,
   "seed_lon": 161.54167,
   "seed_alt_m": 10970.0,
   "seed_age_h": 248.15,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-30 23:45:00",
    "lat": 14.42461,
    "lon": -28.03335,
    "alt_m": 11166.5
   },
   "member_spread_deg": {
    "lat": 49.81,
    "lon": 312.96
   },
   "member_spread_now_deg": {
    "lat": 34.66,
    "lon": 126.53
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "KI6DS-11",
   "flight_id": "KI6DS-11_2026-02-03",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 01:45:45",
   "seed_lat": 81.20828,
   "seed_lon": -145.74998,
   "seed_alt_m": 12720.0,
   "seed_age_h": 27.57,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 23:45:00",
    "lat": 76.5043,
    "lon": -72.04435,
    "alt_m": 13053.2
   },
   "member_spread_deg": {
    "lat": 23.83,
    "lon": 349.52
   },
   "member_spread_now_deg": {
    "lat": 2.74,
    "lon": 176.85
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "KJ4AWK-1",
   "flight_id": "KJ4AWK-1_2026-08-22",
   "payload_type": "APRS",
   "seed_time": "2026-08-23 18:00:24",
   "seed_lat": 51.81083,
   "seed_lon": -61.64733,
   "seed_alt_m": 12996.0,
   "seed_age_h": 11.33,
   "float_reliable": false,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 23:30:00",
    "lat": 44.70309,
    "lon": 174.33787,
    "alt_m": 13134.8
   },
   "member_spread_deg": {
    "lat": 16.08,
    "lon": 66.49
   },
   "member_spread_now_deg": {
    "lat": 7.91,
    "lon": 13.48
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "SP2ROC-41",
   "flight_id": "SP2ROC-41_2026-01-25",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 15:23:00",
   "seed_lat": 17.52083,
   "seed_lon": 13.625,
   "seed_alt_m": 16640.0,
   "seed_age_h": 13.95,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 23:30:00",
    "lat": 47.60814,
    "lon": 75.81608,
    "alt_m": 15810.8
   },
   "member_spread_deg": {
    "lat": 28.08,
    "lon": 173.46
   },
   "member_spread_now_deg": {
    "lat": 1.47,
    "lon": 1.9
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "VE3VRO-36",
   "flight_id": "VE3VRO-36_2026-07-30",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 21:21:00",
   "seed_lat": 51.9375,
   "seed_lon": -68.66667,
   "seed_alt_m": 13160.0,
   "seed_age_h": 7.98,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 23:45:00",
    "lat": 50.8296,
    "lon": 149.30098,
    "alt_m": 13040.7
   },
   "member_spread_deg": {
    "lat": 11.29,
    "lon": 102.68
   },
   "member_spread_now_deg": {
    "lat": 1.57,
    "lon": 12.05
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "ZS6SRC-37",
   "flight_id": "ZS6SRC-37_2026-07-31",
   "payload_type": "WSPR",
   "seed_time": "2026-08-17 20:59:00",
   "seed_lat": -20.58333,
   "seed_lon": -72.33333,
   "seed_alt_m": 12210.0,
   "seed_age_h": 152.35,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-30 23:30:00",
    "lat": -19.9256,
    "lon": -19.89549,
    "alt_m": 12543.5
   },
   "member_spread_deg": {
    "lat": 22.36,
    "lon": 117.4
   },
   "member_spread_now_deg": {
    "lat": 8.68,
    "lon": 314.6
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "ZS6SRC-39",
   "flight_id": "ZS6SRC-39_2026-08-05",
   "payload_type": "WSPR",
   "seed_time": "2026-08-12 06:21:00",
   "seed_lat": -22.16667,
   "seed_lon": 146.45833,
   "seed_alt_m": 15900.0,
   "seed_age_h": 286.98,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-30 23:45:00",
    "lat": -18.76265,
    "lon": 123.54377,
    "alt_m": 15989.0
   },
   "member_spread_deg": {
    "lat": 34.92,
    "lon": 223.36
   },
   "member_spread_now_deg": {
    "lat": 33.27,
    "lon": 221.51
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "ZS6WBT-1",
   "flight_id": "ZS6WBT-1_2026-08-19",
   "payload_type": "WSPR",
   "seed_time": "2026-08-24 03:56:00",
   "seed_lat": -23.66667,
   "seed_lon": 127.875,
   "seed_alt_m": 15530.0,
   "seed_age_h": 1.4,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-31 03:30:00",
    "lat": -28.18787,
    "lon": -23.03511,
    "alt_m": 15422.9
   },
   "member_spread_deg": {
    "lat": 45.89,
    "lon": 34.32
   },
   "member_spread_now_deg": {
    "lat": 0.21,
    "lon": 1.51
   },
   "display_as": "track",
   "display_reason": "fresh"
  }
 ]
}