{
 "generated_utc": "2026-08-12T11:26:43Z",
 "gfs_cycle_utc": "2026-08-12T06:00:00Z",
 "model": {
  "source": "NCEP GFS 0.50 degree",
  "vertical_coordinate": "constant density (isopycnic)",
  "horizon_hours": 457.0,
  "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_20260812_06Z.csv.gz",
  "trajectories_geojson_gz": "PBA_forecast_20260812_06Z.geojson.gz"
 },
 "counts": {
  "flights": 23,
  "members": 9,
  "rows": 97605
 },
 "flights": [
  {
   "callsign": "AG6NS-23",
   "flight_id": "AG6NS-23_2026-02-07",
   "payload_type": "WSPR",
   "seed_time": "2026-08-11 23:53:40",
   "seed_lat": -55.83334,
   "seed_lon": -115.37499,
   "seed_alt_m": 12390.0,
   "seed_age_h": 11.44,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-19 05:30:00",
    "lat": -51.58287,
    "lon": -168.36809,
    "alt_m": 12444.9
   },
   "member_spread_deg": {
    "lat": 29.72,
    "lon": 344.49
   },
   "member_spread_now_deg": {
    "lat": 0.96,
    "lon": 4.92
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS53",
   "flight_id": "BSS53_2026-03-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-12 10:54:48",
   "seed_lat": 63.5,
   "seed_lon": -5.95833,
   "seed_alt_m": 12740.0,
   "seed_age_h": 0.42,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-19 11:00:00",
    "lat": 73.28558,
    "lon": 160.4924,
    "alt_m": 12513.6
   },
   "member_spread_deg": {
    "lat": 24.8,
    "lon": 86.63
   },
   "member_spread_now_deg": {
    "lat": 0.1,
    "lon": 0.2
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS54",
   "flight_id": "BSS54_2026-07-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-11 04:17:39",
   "seed_lat": 47.60417,
   "seed_lon": 117.45833,
   "seed_alt_m": 14140.0,
   "seed_age_h": 31.04,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-19 05:45:00",
    "lat": 38.38637,
    "lon": -144.34546,
    "alt_m": 14263.6
   },
   "member_spread_deg": {
    "lat": 16.14,
    "lon": 37.06
   },
   "member_spread_now_deg": {
    "lat": 6.86,
    "lon": 4.35
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-23",
   "flight_id": "DG2GG-23_2026-05-23",
   "payload_type": "WSPR",
   "seed_time": "2026-08-12 10:49:00",
   "seed_lat": 50.16667,
   "seed_lon": -8.16667,
   "seed_alt_m": 12950.0,
   "seed_age_h": 0.52,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-19 10:15:00",
    "lat": 49.98577,
    "lon": 139.58618,
    "alt_m": 12817.5
   },
   "member_spread_deg": {
    "lat": 5.53,
    "lon": 84.24
   },
   "member_spread_now_deg": {
    "lat": 0.03,
    "lon": 0.06
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-27",
   "flight_id": "DG2GG-27_2026-07-04",
   "payload_type": "WSPR",
   "seed_time": "2026-08-10 00:18:00",
   "seed_lat": 17.10417,
   "seed_lon": -113.33333,
   "seed_alt_m": 14010.0,
   "seed_age_h": 59.03,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-19 05:45:00",
    "lat": 6.06989,
    "lon": -117.77429,
    "alt_m": 14121.2
   },
   "member_spread_deg": {
    "lat": 29.09,
    "lon": 55.65
   },
   "member_spread_now_deg": {
    "lat": 18.81,
    "lon": 31.63
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-29",
   "flight_id": "DG2GG-29_2026-07-28",
   "payload_type": "WSPR",
   "seed_time": "2026-08-04 04:57:00",
   "seed_lat": 46.91667,
   "seed_lon": 165.25,
   "seed_alt_m": 13380.0,
   "seed_age_h": 198.38,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-19 05:30:00",
    "lat": 23.78463,
    "lon": -34.44042,
    "alt_m": 13449.2
   },
   "member_spread_deg": {
    "lat": 73.87,
    "lon": 268.47
   },
   "member_spread_now_deg": {
    "lat": 72.88,
    "lon": 240.3
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "DG2GG-30",
   "flight_id": "DG2GG-30_2026-08-07",
   "payload_type": "WSPR",
   "seed_time": "2026-08-12 05:16:00",
   "seed_lat": 54.60417,
   "seed_lon": 154.08333,
   "seed_alt_m": 12810.0,
   "seed_age_h": 6.07,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-19 05:45:00",
    "lat": 51.2777,
    "lon": -26.03744,
    "alt_m": 12892.0
   },
   "member_spread_deg": {
    "lat": 32.71,
    "lon": 134.0
   },
   "member_spread_now_deg": {
    "lat": 0.89,
    "lon": 1.3
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DN3LEO-13",
   "flight_id": "DN3LEO-13_2026-04-12",
   "payload_type": "WSPR",
   "seed_time": "2026-08-11 16:33:00",
   "seed_lat": 63.0,
   "seed_lon": 3.91667,
   "seed_alt_m": 12360.0,
   "seed_age_h": 18.78,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-19 05:30:00",
    "lat": 61.60268,
    "lon": -102.62706,
    "alt_m": 11952.0
   },
   "member_spread_deg": {
    "lat": 13.03,
    "lon": 245.19
   },
   "member_spread_now_deg": {
    "lat": 6.87,
    "lon": 7.09
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "EI6BFW-18",
   "flight_id": "EI6BFW-18_2026-07-25",
   "payload_type": "WSPR",
   "seed_time": "2026-08-12 00:18:00",
   "seed_lat": 74.52083,
   "seed_lon": -141.04167,
   "seed_alt_m": 12600.0,
   "seed_age_h": 11.03,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-19 05:45:00",
    "lat": 64.65644,
    "lon": -41.19585,
    "alt_m": 12486.6
   },
   "member_spread_deg": {
    "lat": 18.75,
    "lon": 39.96
   },
   "member_spread_now_deg": {
    "lat": 0.63,
    "lon": 4.18
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "K5NOT-11",
   "flight_id": "K5NOT-11_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-10 03:45:37",
   "seed_lat": 33.04161,
   "seed_lon": 175.83333,
   "seed_alt_m": 13420.0,
   "seed_age_h": 55.57,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-19 05:45:00",
    "lat": 23.78275,
    "lon": -51.19591,
    "alt_m": 13430.5
   },
   "member_spread_deg": {
    "lat": 50.83,
    "lon": 282.34
   },
   "member_spread_now_deg": {
    "lat": 27.53,
    "lon": 335.39
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "KC3LBR-449",
   "flight_id": "KC3LBR-449_2026-07-06",
   "payload_type": "WSPR",
   "seed_time": "2026-08-12 10:33:48",
   "seed_lat": 59.4375,
   "seed_lon": -4.875,
   "seed_alt_m": 12750.0,
   "seed_age_h": 0.77,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-19 10:00:00",
    "lat": 70.16445,
    "lon": 84.23935,
    "alt_m": 12627.6
   },
   "member_spread_deg": {
    "lat": 16.47,
    "lon": 93.09
   },
   "member_spread_now_deg": {
    "lat": 0.14,
    "lon": 0.26
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KC5TRB-1",
   "flight_id": "KC5TRB-1_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-12 10:45:43",
   "seed_lat": 57.81245,
   "seed_lon": 24.9167,
   "seed_alt_m": 12660.0,
   "seed_age_h": 0.57,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-19 10:15:00",
    "lat": 55.99627,
    "lon": 82.99977,
    "alt_m": 12425.7
   },
   "member_spread_deg": {
    "lat": 12.09,
    "lon": 179.41
   },
   "member_spread_now_deg": {
    "lat": 0.36,
    "lon": 0.38
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KD7FXO-1",
   "flight_id": "KD7FXO-1_2026-08-02",
   "payload_type": "WSPR",
   "seed_time": "2026-08-12 10:22:30",
   "seed_lat": 40.91667,
   "seed_lon": -8.20833,
   "seed_alt_m": 13110.0,
   "seed_age_h": 0.96,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-19 10:00:00",
    "lat": 48.23408,
    "lon": 146.24556,
    "alt_m": 13047.0
   },
   "member_spread_deg": {
    "lat": 12.44,
    "lon": 99.99
   },
   "member_spread_now_deg": {
    "lat": 0.05,
    "lon": 0.17
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KE8RES-8",
   "flight_id": "KE8RES-8_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-11 21:06:00",
   "seed_lat": 54.45833,
   "seed_lon": -78.16667,
   "seed_alt_m": 12100.0,
   "seed_age_h": 14.23,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-19 05:30:00",
    "lat": 66.87172,
    "lon": -6.4971,
    "alt_m": 12177.6
   },
   "member_spread_deg": {
    "lat": 10.45,
    "lon": 58.25
   },
   "member_spread_now_deg": {
    "lat": 2.0,
    "lon": 5.83
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KE9DAB-11",
   "flight_id": "KE9DAB-11_2026-07-29",
   "payload_type": "WSPR",
   "seed_time": "2026-08-12 08:48:30",
   "seed_lat": 38.77083,
   "seed_lon": 107.91667,
   "seed_alt_m": 12330.0,
   "seed_age_h": 2.53,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-19 08:15:00",
    "lat": 41.72713,
    "lon": -115.19007,
    "alt_m": 12589.4
   },
   "member_spread_deg": {
    "lat": 28.71,
    "lon": 310.51
   },
   "member_spread_now_deg": {
    "lat": 1.02,
    "lon": 1.28
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KI1TEN-1",
   "flight_id": "KI1TEN-1_2026-07-23",
   "payload_type": "WSPR",
   "seed_time": "2026-08-01 22:55:27",
   "seed_lat": 23.95828,
   "seed_lon": -104.12496,
   "seed_alt_m": 12380.0,
   "seed_age_h": 252.41,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-19 05:30:00",
    "lat": 8.98998,
    "lon": -102.76965,
    "alt_m": 12401.1
   },
   "member_spread_deg": {
    "lat": 53.88,
    "lon": 170.96
   },
   "member_spread_now_deg": {
    "lat": 20.98,
    "lon": 52.27
   },
   "display_as": "region",
   "display_reason": "seed_age"
  },
  {
   "callsign": "KI6DS-11",
   "flight_id": "KI6DS-11_2026-02-03",
   "payload_type": "WSPR",
   "seed_time": "2026-08-11 06:35:45",
   "seed_lat": 54.72911,
   "seed_lon": 24.66669,
   "seed_alt_m": 13360.0,
   "seed_age_h": 28.74,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-19 05:30:00",
    "lat": 62.74539,
    "lon": 142.36463,
    "alt_m": 13025.2
   },
   "member_spread_deg": {
    "lat": 27.88,
    "lon": 306.77
   },
   "member_spread_now_deg": {
    "lat": 10.68,
    "lon": 6.22
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "SP2ROC-41",
   "flight_id": "SP2ROC-41_2026-01-25",
   "payload_type": "WSPR",
   "seed_time": "2026-08-12 04:41:00",
   "seed_lat": 31.625,
   "seed_lon": 178.95833,
   "seed_alt_m": 16360.0,
   "seed_age_h": 6.65,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-19 05:45:00",
    "lat": 7.69192,
    "lon": 101.46551,
    "alt_m": 16303.1
   },
   "member_spread_deg": {
    "lat": 46.47,
    "lon": 78.11
   },
   "member_spread_now_deg": {
    "lat": 3.73,
    "lon": 359.44
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "SP6MPL-34",
   "flight_id": "SP6MPL-34_2025-12-03",
   "payload_type": "WSPR",
   "seed_time": "2026-07-31 18:52:00",
   "seed_lat": 74.5625,
   "seed_lon": -160.0,
   "seed_alt_m": 12890.0,
   "seed_age_h": 280.47,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-19 05:45:00",
    "lat": 56.90494,
    "lon": -47.16446,
    "alt_m": 12971.6
   },
   "member_spread_deg": {
    "lat": 30.24,
    "lon": 272.73
   },
   "member_spread_now_deg": {
    "lat": 10.34,
    "lon": 329.61
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "SP6MPL-9",
   "flight_id": "SP6MPL-9_2026-08-02",
   "payload_type": "APRS",
   "seed_time": "2026-08-04 04:05:45",
   "seed_lat": 45.52942,
   "seed_lon": 75.286,
   "seed_alt_m": 12836.0,
   "seed_age_h": 199.24,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-19 05:30:00",
    "lat": 57.46465,
    "lon": 169.35202,
    "alt_m": 12482.0
   },
   "member_spread_deg": {
    "lat": 27.09,
    "lon": 332.12
   },
   "member_spread_now_deg": {
    "lat": 27.74,
    "lon": 318.56
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "VE3VRO-36",
   "flight_id": "VE3VRO-36_2026-07-30",
   "payload_type": "WSPR",
   "seed_time": "2026-08-12 06:51:00",
   "seed_lat": 47.125,
   "seed_lon": 146.33333,
   "seed_alt_m": 13700.0,
   "seed_age_h": 4.48,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-19 06:15:00",
    "lat": 39.97875,
    "lon": -140.51349,
    "alt_m": 13474.5
   },
   "member_spread_deg": {
    "lat": 37.01,
    "lon": 319.64
   },
   "member_spread_now_deg": {
    "lat": 0.27,
    "lon": 2.33
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "ZS6SRC-37",
   "flight_id": "ZS6SRC-37_2026-07-15",
   "payload_type": "WSPR",
   "seed_time": "2026-07-31 04:34:00",
   "seed_lat": -23.70833,
   "seed_lon": 149.29167,
   "seed_alt_m": 12380.0,
   "seed_age_h": 294.77,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-19 05:30:00",
    "lat": -3.15651,
    "lon": 33.28897,
    "alt_m": 12687.4
   },
   "member_spread_deg": {
    "lat": 28.64,
    "lon": 224.64
   },
   "member_spread_now_deg": {
    "lat": 23.96,
    "lon": 257.79
   },
   "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": 4.98,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-19 05:45:00",
    "lat": -22.70405,
    "lon": -31.72056,
    "alt_m": 15617.0
   },
   "member_spread_deg": {
    "lat": 20.82,
    "lon": 300.74
   },
   "member_spread_now_deg": {
    "lat": 1.57,
    "lon": 3.67
   },
   "display_as": "track",
   "display_reason": "fresh"
  }
 ]
}