{
 "generated_utc": "2026-08-23T11:27:12Z",
 "gfs_cycle_utc": "2026-08-23T06:00:00Z",
 "model": {
  "source": "NCEP GFS 0.50 degree",
  "vertical_coordinate": "constant density (isopycnic)",
  "horizon_hours": 485.5,
  "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_06Z.csv.gz",
  "trajectories_geojson_gz": "PBA_forecast_20260823_06Z.geojson.gz"
 },
 "counts": {
  "flights": 23,
  "members": 9,
  "rows": 95823
 },
 "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": 21.61,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 05:45:00",
    "lat": -61.00522,
    "lon": 72.49674,
    "alt_m": 12495.8
   },
   "member_spread_deg": {
    "lat": 8.38,
    "lon": 230.47
   },
   "member_spread_now_deg": {
    "lat": 7.92,
    "lon": 34.43
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS53",
   "flight_id": "BSS53_2026-03-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 10:50:48",
   "seed_lat": 80.41667,
   "seed_lon": -83.79167,
   "seed_alt_m": 12300.0,
   "seed_age_h": 0.49,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-30 10:45:00",
    "lat": 60.67286,
    "lon": 68.3051,
    "alt_m": 12237.8
   },
   "member_spread_deg": {
    "lat": 17.34,
    "lon": 95.35
   },
   "member_spread_now_deg": {
    "lat": 0.02,
    "lon": 0.2
   },
   "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": 13.63,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-30 05:45:00",
    "lat": 67.43672,
    "lon": 28.42041,
    "alt_m": 13746.3
   },
   "member_spread_deg": {
    "lat": 27.33,
    "lon": 113.74
   },
   "member_spread_now_deg": {
    "lat": 3.7,
    "lon": 4.28
   },
   "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": 9.02,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 05:45:00",
    "lat": 64.52735,
    "lon": 16.56121,
    "alt_m": 12541.6
   },
   "member_spread_deg": {
    "lat": 25.61,
    "lon": 65.58
   },
   "member_spread_now_deg": {
    "lat": 2.53,
    "lon": 5.29
   },
   "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": 323.03,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-30 05:45:00",
    "lat": -2.40995,
    "lon": -12.68002,
    "alt_m": 13993.9
   },
   "member_spread_deg": {
    "lat": 72.14,
    "lon": 235.11
   },
   "member_spread_now_deg": {
    "lat": 57.88,
    "lon": 122.99
   },
   "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 06:56:00",
   "seed_lat": 49.85417,
   "seed_lon": 87.375,
   "seed_alt_m": 12530.0,
   "seed_age_h": 4.4,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 06:30:00",
    "lat": 55.13601,
    "lon": -94.632,
    "alt_m": 12610.9
   },
   "member_spread_deg": {
    "lat": 26.45,
    "lon": 68.92
   },
   "member_spread_now_deg": {
    "lat": 0.48,
    "lon": 3.68
   },
   "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": 8.55,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 05:45:00",
    "lat": 52.06145,
    "lon": -35.91404,
    "alt_m": 13109.3
   },
   "member_spread_deg": {
    "lat": 20.04,
    "lon": 77.57
   },
   "member_spread_now_deg": {
    "lat": 2.07,
    "lon": 3.33
   },
   "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": 7.12,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-30 05:45:00",
    "lat": 61.36506,
    "lon": -26.53596,
    "alt_m": 11806.2
   },
   "member_spread_deg": {
    "lat": 29.8,
    "lon": 183.38
   },
   "member_spread_now_deg": {
    "lat": 0.58,
    "lon": 6.88
   },
   "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": 19.45,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 05:30:00",
    "lat": 47.39627,
    "lon": 128.86197,
    "alt_m": 12733.3
   },
   "member_spread_deg": {
    "lat": 36.0,
    "lon": 308.62
   },
   "member_spread_now_deg": {
    "lat": 3.18,
    "lon": 9.17
   },
   "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": 182.49,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 05:45:00",
    "lat": 31.31103,
    "lon": -65.0875,
    "alt_m": 13390.1
   },
   "member_spread_deg": {
    "lat": 37.09,
    "lon": 264.85
   },
   "member_spread_now_deg": {
    "lat": 17.62,
    "lon": 76.31
   },
   "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 10:47:18",
   "seed_lat": 58.875,
   "seed_lon": 131.375,
   "seed_alt_m": 13220.0,
   "seed_age_h": 0.55,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 10:45:00",
    "lat": 47.53118,
    "lon": -78.87188,
    "alt_m": 13374.5
   },
   "member_spread_deg": {
    "lat": 38.24,
    "lon": 126.31
   },
   "member_spread_now_deg": {
    "lat": 0.08,
    "lon": 0.24
   },
   "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": 263.66,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 05:45:00",
    "lat": 55.44206,
    "lon": 166.28943,
    "alt_m": 12695.4
   },
   "member_spread_deg": {
    "lat": 29.11,
    "lon": 311.75
   },
   "member_spread_now_deg": {
    "lat": 33.53,
    "lon": 309.33
   },
   "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": 20.35,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-30 05:30:00",
    "lat": 28.20408,
    "lon": 6.09922,
    "alt_m": 11603.8
   },
   "member_spread_deg": {
    "lat": 20.26,
    "lon": 152.42
   },
   "member_spread_now_deg": {
    "lat": 3.15,
    "lon": 3.16
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KD7FXO-1",
   "flight_id": "KD7FXO-1_2026-08-02",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 04:55:00",
   "seed_lat": 31.64583,
   "seed_lon": -179.04167,
   "seed_alt_m": 13060.0,
   "seed_age_h": 6.42,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 05:30:00",
    "lat": 25.51577,
    "lon": -163.33315,
    "alt_m": 13059.2
   },
   "member_spread_deg": {
    "lat": 10.13,
    "lon": 87.94
   },
   "member_spread_now_deg": {
    "lat": 3.08,
    "lon": 359.98
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "KE8RES-8",
   "flight_id": "KE8RES-8_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 05:06:00",
   "seed_lat": 70.6875,
   "seed_lon": 178.08333,
   "seed_alt_m": 11840.0,
   "seed_age_h": 6.23,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-30 05:30:00",
    "lat": 60.45795,
    "lon": 92.76979,
    "alt_m": 11918.5
   },
   "member_spread_deg": {
    "lat": 25.86,
    "lon": 225.97
   },
   "member_spread_now_deg": {
    "lat": 0.24,
    "lon": 5.4
   },
   "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": 230.15,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-30 05:45:00",
    "lat": 36.2086,
    "lon": -9.76226,
    "alt_m": 11214.1
   },
   "member_spread_deg": {
    "lat": 22.5,
    "lon": 302.38
   },
   "member_spread_now_deg": {
    "lat": 21.27,
    "lon": 100.82
   },
   "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": 9.57,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 05:45:00",
    "lat": 69.1686,
    "lon": -175.88388,
    "alt_m": 12870.7
   },
   "member_spread_deg": {
    "lat": 21.95,
    "lon": 356.07
   },
   "member_spread_now_deg": {
    "lat": 2.4,
    "lon": 3.11
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "SP2ROC-41",
   "flight_id": "SP2ROC-41_2026-01-25",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 10:51:00",
   "seed_lat": 17.41667,
   "seed_lon": 15.91667,
   "seed_alt_m": 16670.0,
   "seed_age_h": 0.48,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 10:45:00",
    "lat": 46.45976,
    "lon": 71.75108,
    "alt_m": 15871.5
   },
   "member_spread_deg": {
    "lat": 27.59,
    "lon": 144.1
   },
   "member_spread_now_deg": {
    "lat": 0.05,
    "lon": 0.11
   },
   "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": 12.82,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 05:30:00",
    "lat": 47.36447,
    "lon": 132.57919,
    "alt_m": 13064.3
   },
   "member_spread_deg": {
    "lat": 25.74,
    "lon": 150.52
   },
   "member_spread_now_deg": {
    "lat": 3.75,
    "lon": 4.84
   },
   "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": 13.66,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-30 05:45:00",
    "lat": 47.77431,
    "lon": 67.76182,
    "alt_m": 13218.2
   },
   "member_spread_deg": {
    "lat": 15.75,
    "lon": 54.62
   },
   "member_spread_now_deg": {
    "lat": 2.73,
    "lon": 4.41
   },
   "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": 134.35,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-30 05:30:00",
    "lat": -15.61435,
    "lon": -30.85889,
    "alt_m": 12413.1
   },
   "member_spread_deg": {
    "lat": 27.96,
    "lon": 122.82
   },
   "member_spread_now_deg": {
    "lat": 17.45,
    "lon": 326.56
   },
   "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": 268.98,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-30 05:45:00",
    "lat": -22.45129,
    "lon": 106.40951,
    "alt_m": 15982.4
   },
   "member_spread_deg": {
    "lat": 24.52,
    "lon": 228.92
   },
   "member_spread_now_deg": {
    "lat": 27.69,
    "lon": 199.53
   },
   "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 08:01:00",
   "seed_lat": -21.5,
   "seed_lon": 112.91667,
   "seed_alt_m": 15710.0,
   "seed_age_h": 3.32,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-30 07:30:00",
    "lat": -33.7683,
    "lon": -37.54805,
    "alt_m": 15077.9
   },
   "member_spread_deg": {
    "lat": 34.1,
    "lon": 70.13
   },
   "member_spread_now_deg": {
    "lat": 1.13,
    "lon": 2.43
   },
   "display_as": "track",
   "display_reason": "fresh"
  }
 ]
}