{
 "generated_utc": "2026-08-23T05:27:14Z",
 "gfs_cycle_utc": "2026-08-23T00:00:00Z",
 "model": {
  "source": "NCEP GFS 0.50 degree",
  "vertical_coordinate": "constant density (isopycnic)",
  "horizon_hours": 479.5,
  "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_20260823_00Z.csv.gz",
  "trajectories_geojson_gz": "PBA_forecast_20260823_00Z.geojson.gz"
 },
 "counts": {
  "flights": 23,
  "members": 9,
  "rows": 94410
 },
 "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": 15.61,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 23:45:00",
    "lat": -64.40329,
    "lon": 72.16155,
    "alt_m": 12278.9
   },
   "member_spread_deg": {
    "lat": 10.14,
    "lon": 225.13
   },
   "member_spread_now_deg": {
    "lat": 4.32,
    "lon": 24.55
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS53",
   "flight_id": "BSS53_2026-03-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 04:26:18",
   "seed_lat": 80.9375,
   "seed_lon": -93.33333,
   "seed_alt_m": 12280.0,
   "seed_age_h": 0.9,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-30 04:00:00",
    "lat": 67.26552,
    "lon": 59.08131,
    "alt_m": 12134.4
   },
   "member_spread_deg": {
    "lat": 22.74,
    "lon": 105.81
   },
   "member_spread_now_deg": {
    "lat": 0.05,
    "lon": 0.71
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS54",
   "flight_id": "BSS54_2026-07-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-22 21:42:18",
   "seed_lat": 41.04167,
   "seed_lon": -89.125,
   "seed_alt_m": 14010.0,
   "seed_age_h": 7.63,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-29 23:45:00",
    "lat": 48.61515,
    "lon": 46.69083,
    "alt_m": 13825.0
   },
   "member_spread_deg": {
    "lat": 10.9,
    "lon": 96.9
   },
   "member_spread_now_deg": {
    "lat": 0.65,
    "lon": 3.59
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-23",
   "flight_id": "DG2GG-23_2026-05-23",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 02:19:00",
   "seed_lat": 35.91667,
   "seed_lon": -146.25,
   "seed_alt_m": 13020.0,
   "seed_age_h": 3.02,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 01:45:00",
    "lat": 39.71073,
    "lon": 48.3182,
    "alt_m": 12746.7
   },
   "member_spread_deg": {
    "lat": 28.68,
    "lon": 112.84
   },
   "member_spread_now_deg": {
    "lat": 0.63,
    "lon": 2.3
   },
   "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": 317.03,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-29 23:45:00",
    "lat": -4.2211,
    "lon": -17.04047,
    "alt_m": 14042.6
   },
   "member_spread_deg": {
    "lat": 68.02,
    "lon": 203.73
   },
   "member_spread_now_deg": {
    "lat": 58.36,
    "lon": 122.74
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "DG2GG-30",
   "flight_id": "DG2GG-30_2026-08-07",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 03:56:00",
   "seed_lat": 49.5,
   "seed_lon": 83.5,
   "seed_alt_m": 12540.0,
   "seed_age_h": 1.4,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 03:30:00",
    "lat": 64.86458,
    "lon": -114.15432,
    "alt_m": 12525.9
   },
   "member_spread_deg": {
    "lat": 27.37,
    "lon": 58.06
   },
   "member_spread_now_deg": {
    "lat": 0.16,
    "lon": 0.7
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-31",
   "flight_id": "DG2GG-31_2026-08-13",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 02:47:00",
   "seed_lat": 55.54167,
   "seed_lon": -162.25,
   "seed_alt_m": 13120.0,
   "seed_age_h": 2.55,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 02:15:00",
    "lat": 47.74205,
    "lon": -41.90294,
    "alt_m": 13138.8
   },
   "member_spread_deg": {
    "lat": 22.29,
    "lon": 77.9
   },
   "member_spread_now_deg": {
    "lat": 0.77,
    "lon": 1.45
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DN3LEO-13",
   "flight_id": "DN3LEO-13_2026-04-12",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 04:13:00",
   "seed_lat": 69.47917,
   "seed_lon": -178.58333,
   "seed_alt_m": 11780.0,
   "seed_age_h": 1.12,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-30 03:45:00",
    "lat": 66.5834,
    "lon": -16.90865,
    "alt_m": 11916.9
   },
   "member_spread_deg": {
    "lat": 33.85,
    "lon": 248.56
   },
   "member_spread_now_deg": {
    "lat": 0.02,
    "lon": 1.53
   },
   "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": 13.45,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 23:30:00",
    "lat": 77.04268,
    "lon": 117.08957,
    "alt_m": 12651.7
   },
   "member_spread_deg": {
    "lat": 28.91,
    "lon": 322.28
   },
   "member_spread_now_deg": {
    "lat": 1.71,
    "lon": 4.38
   },
   "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": 176.49,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 23:45:00",
    "lat": 7.14476,
    "lon": -52.02373,
    "alt_m": 13370.9
   },
   "member_spread_deg": {
    "lat": 43.05,
    "lon": 255.53
   },
   "member_spread_now_deg": {
    "lat": 16.61,
    "lon": 71.4
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "KC3LBR-449",
   "flight_id": "KC3LBR-449_2026-07-06",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 00:03:49",
   "seed_lat": 60.9375,
   "seed_lon": 121.25,
   "seed_alt_m": 13240.0,
   "seed_age_h": 5.27,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 23:30:00",
    "lat": 52.39049,
    "lon": -86.5891,
    "alt_m": 13291.8
   },
   "member_spread_deg": {
    "lat": 39.11,
    "lon": 178.74
   },
   "member_spread_now_deg": {
    "lat": 0.12,
    "lon": 0.85
   },
   "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": 257.66,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 23:45:00",
    "lat": 56.84959,
    "lon": 157.46769,
    "alt_m": 12654.3
   },
   "member_spread_deg": {
    "lat": 31.08,
    "lon": 304.16
   },
   "member_spread_now_deg": {
    "lat": 36.29,
    "lon": 305.94
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "KC7RW-3",
   "flight_id": "KC7RW-3_2026-08-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-22 14:59:00",
   "seed_lat": 47.54167,
   "seed_lon": -29.75,
   "seed_alt_m": 11670.0,
   "seed_age_h": 14.35,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-29 23:30:00",
    "lat": 26.88303,
    "lon": -0.7284,
    "alt_m": 11627.2
   },
   "member_spread_deg": {
    "lat": 17.08,
    "lon": 156.88
   },
   "member_spread_now_deg": {
    "lat": 3.49,
    "lon": 1.16
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KD7FXO-1",
   "flight_id": "KD7FXO-1_2026-08-02",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 04:45:00",
   "seed_lat": 31.75,
   "seed_lon": -179.04167,
   "seed_alt_m": 13050.0,
   "seed_age_h": 0.58,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 04:45:00",
    "lat": 35.56752,
    "lon": 171.71764,
    "alt_m": 13037.4
   },
   "member_spread_deg": {
    "lat": 11.04,
    "lon": 343.85
   },
   "member_spread_now_deg": {
    "lat": 0.21,
    "lon": 0.07
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KE8RES-8",
   "flight_id": "KE8RES-8_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 04:41:00",
   "seed_lat": 70.64583,
   "seed_lon": 177.33333,
   "seed_alt_m": 11800.0,
   "seed_age_h": 0.65,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-30 04:45:00",
    "lat": 66.4527,
    "lon": 88.58289,
    "alt_m": 11734.6
   },
   "member_spread_deg": {
    "lat": 30.08,
    "lon": 233.62
   },
   "member_spread_now_deg": {
    "lat": 0.04,
    "lon": 0.42
   },
   "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": 224.15,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-29 23:45:00",
    "lat": 26.95037,
    "lon": -20.97011,
    "alt_m": 11163.4
   },
   "member_spread_deg": {
    "lat": 38.91,
    "lon": 312.19
   },
   "member_spread_now_deg": {
    "lat": 16.61,
    "lon": 97.71
   },
   "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": 3.57,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 01:15:00",
    "lat": 75.39002,
    "lon": -153.36338,
    "alt_m": 12844.0
   },
   "member_spread_deg": {
    "lat": 16.14,
    "lon": 316.46
   },
   "member_spread_now_deg": {
    "lat": 1.09,
    "lon": 0.77
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "SP2ROC-41",
   "flight_id": "SP2ROC-41_2026-01-25",
   "payload_type": "WSPR",
   "seed_time": "2026-08-22 14:18:00",
   "seed_lat": 13.52083,
   "seed_lon": 30.0,
   "seed_alt_m": 16560.0,
   "seed_age_h": 15.03,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 23:45:00",
    "lat": 37.5915,
    "lon": 21.53148,
    "alt_m": 16357.3
   },
   "member_spread_deg": {
    "lat": 30.53,
    "lon": 141.41
   },
   "member_spread_now_deg": {
    "lat": 3.53,
    "lon": 3.26
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "VE3VRO-36",
   "flight_id": "VE3VRO-36_2026-07-30",
   "payload_type": "WSPR",
   "seed_time": "2026-08-22 22:31:00",
   "seed_lat": 38.70833,
   "seed_lon": -88.75,
   "seed_alt_m": 13270.0,
   "seed_age_h": 6.82,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 23:30:00",
    "lat": 44.78262,
    "lon": 126.4784,
    "alt_m": 12855.8
   },
   "member_spread_deg": {
    "lat": 16.44,
    "lon": 141.64
   },
   "member_spread_now_deg": {
    "lat": 1.09,
    "lon": 3.76
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "W0RBO-12",
   "flight_id": "W0RBO-12_2026-05-02",
   "payload_type": "WSPR",
   "seed_time": "2026-08-22 21:40:23",
   "seed_lat": 56.83328,
   "seed_lon": -87.12498,
   "seed_alt_m": 13000.0,
   "seed_age_h": 7.66,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 23:45:00",
    "lat": 49.91121,
    "lon": 55.36929,
    "alt_m": 13298.7
   },
   "member_spread_deg": {
    "lat": 15.83,
    "lon": 12.1
   },
   "member_spread_now_deg": {
    "lat": 1.05,
    "lon": 2.18
   },
   "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": 128.35,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-29 23:30:00",
    "lat": -12.57484,
    "lon": -38.17044,
    "alt_m": 12474.0
   },
   "member_spread_deg": {
    "lat": 29.38,
    "lon": 110.69
   },
   "member_spread_now_deg": {
    "lat": 18.21,
    "lon": 357.11
   },
   "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": 262.98,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-29 23:45:00",
    "lat": -25.58732,
    "lon": 112.11797,
    "alt_m": 15960.6
   },
   "member_spread_deg": {
    "lat": 16.65,
    "lon": 238.07
   },
   "member_spread_now_deg": {
    "lat": 26.34,
    "lon": 193.42
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "ZS6WBT-1",
   "flight_id": "ZS6WBT-1_2026-08-19",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 03:56:00",
   "seed_lat": -22.25,
   "seed_lon": 110.95833,
   "seed_alt_m": 15680.0,
   "seed_age_h": 1.4,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-30 03:30:00",
    "lat": -31.70095,
    "lon": -44.7531,
    "alt_m": 15173.6
   },
   "member_spread_deg": {
    "lat": 26.77,
    "lon": 57.11
   },
   "member_spread_now_deg": {
    "lat": 0.32,
    "lon": 1.14
   },
   "display_as": "track",
   "display_reason": "fresh"
  }
 ]
}