{
 "generated_utc": "2026-08-10T17:27:41Z",
 "gfs_cycle_utc": "2026-08-10T12:00:00Z",
 "model": {
  "source": "NCEP GFS 0.50 degree",
  "vertical_coordinate": "constant density (isopycnic)",
  "horizon_hours": 482.5,
  "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_20260810_12Z.csv.gz",
  "trajectories_geojson_gz": "PBA_forecast_20260810_12Z.geojson.gz"
 },
 "counts": {
  "flights": 26,
  "members": 9,
  "rows": 122094
 },
 "flights": [
  {
   "callsign": "AG6NS-23",
   "flight_id": "AG6NS-23_2026-02-07",
   "payload_type": "WSPR",
   "seed_time": "2026-08-10 02:53:40",
   "seed_lat": -54.9375,
   "seed_lon": -164.20832,
   "seed_alt_m": 12540.0,
   "seed_age_h": 14.44,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-17 11:30:00",
    "lat": -50.64512,
    "lon": 111.22456,
    "alt_m": 12444.3
   },
   "member_spread_deg": {
    "lat": 41.33,
    "lon": 340.68
   },
   "member_spread_now_deg": {
    "lat": 3.64,
    "lon": 3.68
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS53",
   "flight_id": "BSS53_2026-03-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-10 16:56:18",
   "seed_lat": 49.20833,
   "seed_lon": -36.0,
   "seed_alt_m": 12550.0,
   "seed_age_h": 0.4,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-17 17:00:00",
    "lat": 54.86415,
    "lon": 116.32642,
    "alt_m": 12696.1
   },
   "member_spread_deg": {
    "lat": 33.6,
    "lon": 59.75
   },
   "member_spread_now_deg": {
    "lat": 0.23,
    "lon": 0.1
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS54",
   "flight_id": "BSS54_2026-07-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-10 10:45:19",
   "seed_lat": 43.70833,
   "seed_lon": 98.83333,
   "seed_alt_m": 14180.0,
   "seed_age_h": 6.58,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-17 11:45:00",
    "lat": 36.8118,
    "lon": 150.88455,
    "alt_m": 14510.9
   },
   "member_spread_deg": {
    "lat": 16.6,
    "lon": 305.35
   },
   "member_spread_now_deg": {
    "lat": 0.73,
    "lon": 2.89
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-23",
   "flight_id": "DG2GG-23_2026-05-23",
   "payload_type": "WSPR",
   "seed_time": "2026-08-10 16:29:00",
   "seed_lat": 41.0625,
   "seed_lon": -46.20833,
   "seed_alt_m": 12930.0,
   "seed_age_h": 0.85,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-17 16:00:00",
    "lat": 47.11117,
    "lon": 57.05276,
    "alt_m": 12635.1
   },
   "member_spread_deg": {
    "lat": 7.85,
    "lon": 58.79
   },
   "member_spread_now_deg": {
    "lat": 0.13,
    "lon": 0.22
   },
   "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": 17.03,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-17 11:45:00",
    "lat": -6.58024,
    "lon": -130.59401,
    "alt_m": 14029.8
   },
   "member_spread_deg": {
    "lat": 22.46,
    "lon": 34.14
   },
   "member_spread_now_deg": {
    "lat": 4.78,
    "lon": 5.42
   },
   "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": 156.38,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-17 11:30:00",
    "lat": 17.6595,
    "lon": -85.89121,
    "alt_m": 13729.7
   },
   "member_spread_deg": {
    "lat": 75.18,
    "lon": 275.4
   },
   "member_spread_now_deg": {
    "lat": 48.51,
    "lon": 292.48
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "DJ2DS-34",
   "flight_id": "DJ2DS-34_2026-04-22",
   "payload_type": "WSPR",
   "seed_time": "2026-07-28 14:41:00",
   "seed_lat": 30.70833,
   "seed_lon": -70.5,
   "seed_alt_m": 9190.0,
   "seed_age_h": 314.65,
   "float_reliable": false,
   "dead_reckoned": true,
   "levels_spanned": 4,
   "nominal_end": {
    "valid_time": "2026-08-17 11:45:00",
    "lat": 19.1797,
    "lon": 100.48803,
    "alt_m": 9055.3
   },
   "member_spread_deg": {
    "lat": 48.9,
    "lon": 306.93
   },
   "member_spread_now_deg": {
    "lat": 51.51,
    "lon": 140.99
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "DL0MZ-493",
   "flight_id": "DL0MZ-493_2026-07-25",
   "payload_type": "WSPR",
   "seed_time": "2026-07-29 07:36:01",
   "seed_lat": 64.20833,
   "seed_lon": 58.16667,
   "seed_alt_m": 12170.0,
   "seed_age_h": 297.73,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-17 11:30:00",
    "lat": 56.81436,
    "lon": 77.05676,
    "alt_m": 11993.3
   },
   "member_spread_deg": {
    "lat": 58.01,
    "lon": 251.19
   },
   "member_spread_now_deg": {
    "lat": 37.5,
    "lon": 247.05
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "DL0MZ-493e",
   "flight_id": "DL0MZ-493e_2026-07-25",
   "payload_type": "WSPR",
   "seed_time": "2026-07-29 07:27:02",
   "seed_lat": 64.15625,
   "seed_lon": 58.08889,
   "seed_alt_m": 12170.0,
   "seed_age_h": 297.88,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-17 11:30:00",
    "lat": 22.41626,
    "lon": -78.45059,
    "alt_m": 12726.8
   },
   "member_spread_deg": {
    "lat": 64.28,
    "lon": 235.29
   },
   "member_spread_now_deg": {
    "lat": 32.27,
    "lon": 103.15
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "DN3LEO-13",
   "flight_id": "DN3LEO-13_2026-04-12",
   "payload_type": "WSPR",
   "seed_time": "2026-08-10 16:53:00",
   "seed_lat": 60.83333,
   "seed_lon": -29.54167,
   "seed_alt_m": 12280.0,
   "seed_age_h": 0.45,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-17 17:00:00",
    "lat": 66.61173,
    "lon": -124.11181,
    "alt_m": 12186.2
   },
   "member_spread_deg": {
    "lat": 22.12,
    "lon": 257.87
   },
   "member_spread_now_deg": {
    "lat": 0.16,
    "lon": 0.28
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "EI6BFW-18",
   "flight_id": "EI6BFW-18_2026-07-25",
   "payload_type": "WSPR",
   "seed_time": "2026-08-10 16:05:30",
   "seed_lat": 70.72917,
   "seed_lon": -117.83333,
   "seed_alt_m": 12605.0,
   "seed_age_h": 1.24,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-17 15:30:00",
    "lat": 71.12904,
    "lon": -97.546,
    "alt_m": 12249.2
   },
   "member_spread_deg": {
    "lat": 17.63,
    "lon": 28.62
   },
   "member_spread_now_deg": {
    "lat": 0.26,
    "lon": 0.53
   },
   "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": 13.57,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-17 11:45:00",
    "lat": 24.97878,
    "lon": -81.30822,
    "alt_m": 13556.2
   },
   "member_spread_deg": {
    "lat": 34.52,
    "lon": 285.27
   },
   "member_spread_now_deg": {
    "lat": 2.02,
    "lon": 8.78
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KC3LBR-449",
   "flight_id": "KC3LBR-449_2026-07-06",
   "payload_type": "WSPR",
   "seed_time": "2026-08-10 16:57:03",
   "seed_lat": 49.52083,
   "seed_lon": -39.58333,
   "seed_alt_m": 13520.0,
   "seed_age_h": 0.38,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-17 17:00:00",
    "lat": 54.35982,
    "lon": 98.76528,
    "alt_m": 13441.6
   },
   "member_spread_deg": {
    "lat": 27.73,
    "lon": 52.66
   },
   "member_spread_now_deg": {
    "lat": 0.11,
    "lon": 0.09
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KC3LBR-485",
   "flight_id": "KC3LBR-485_2026-03-19",
   "payload_type": "WSPR",
   "seed_time": "2026-07-28 09:08:18",
   "seed_lat": 50.14583,
   "seed_lon": 23.375,
   "seed_alt_m": 12850.0,
   "seed_age_h": 320.2,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-17 11:45:00",
    "lat": 62.14168,
    "lon": 29.7572,
    "alt_m": 12727.2
   },
   "member_spread_deg": {
    "lat": 42.55,
    "lon": 215.3
   },
   "member_spread_now_deg": {
    "lat": 38.44,
    "lon": 316.13
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "KC5TRB-1",
   "flight_id": "KC5TRB-1_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-10 16:55:43",
   "seed_lat": 63.49995,
   "seed_lon": -28.5833,
   "seed_alt_m": 12660.0,
   "seed_age_h": 0.41,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-17 17:00:00",
    "lat": 53.63985,
    "lon": 60.01674,
    "alt_m": 12459.5
   },
   "member_spread_deg": {
    "lat": 18.76,
    "lon": 197.13
   },
   "member_spread_now_deg": {
    "lat": 0.02,
    "lon": 0.23
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KD7FXO-1",
   "flight_id": "KD7FXO-1_2026-08-02",
   "payload_type": "WSPR",
   "seed_time": "2026-08-10 15:55:00",
   "seed_lat": 37.1875,
   "seed_lon": -19.58333,
   "seed_alt_m": 13130.0,
   "seed_age_h": 1.42,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-17 15:30:00",
    "lat": 43.88772,
    "lon": 65.18887,
    "alt_m": 12673.7
   },
   "member_spread_deg": {
    "lat": 7.65,
    "lon": 61.0
   },
   "member_spread_now_deg": {
    "lat": 0.27,
    "lon": 0.31
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KE8RES-8",
   "flight_id": "KE8RES-8_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-10 16:41:00",
   "seed_lat": 54.9375,
   "seed_lon": -87.91667,
   "seed_alt_m": 12030.0,
   "seed_age_h": 0.65,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-17 16:15:00",
    "lat": 51.00952,
    "lon": 4.52581,
    "alt_m": 12502.5
   },
   "member_spread_deg": {
    "lat": 31.36,
    "lon": 112.77
   },
   "member_spread_now_deg": {
    "lat": 0.04,
    "lon": 0.15
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KE9DAB-11",
   "flight_id": "KE9DAB-11_2026-07-29",
   "payload_type": "WSPR",
   "seed_time": "2026-08-10 12:21:00",
   "seed_lat": 44.04167,
   "seed_lon": 64.29167,
   "seed_alt_m": 12010.0,
   "seed_age_h": 4.98,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-17 11:45:00",
    "lat": 34.87557,
    "lon": 173.86187,
    "alt_m": 12454.3
   },
   "member_spread_deg": {
    "lat": 35.34,
    "lon": 340.64
   },
   "member_spread_now_deg": {
    "lat": 0.75,
    "lon": 2.1
   },
   "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": 210.41,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-17 11:30:00",
    "lat": 2.50374,
    "lon": -101.94967,
    "alt_m": 12384.2
   },
   "member_spread_deg": {
    "lat": 20.75,
    "lon": 116.74
   },
   "member_spread_now_deg": {
    "lat": 20.63,
    "lon": 37.05
   },
   "display_as": "region",
   "display_reason": "seed_age"
  },
  {
   "callsign": "KI6DS-11",
   "flight_id": "KI6DS-11_2026-02-03",
   "payload_type": "WSPR",
   "seed_time": "2026-08-10 16:55:45",
   "seed_lat": 55.85411,
   "seed_lon": 4.33335,
   "seed_alt_m": 13450.0,
   "seed_age_h": 0.41,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-17 17:00:00",
    "lat": 62.65985,
    "lon": 101.22541,
    "alt_m": 13307.0
   },
   "member_spread_deg": {
    "lat": 34.19,
    "lon": 338.83
   },
   "member_spread_now_deg": {
    "lat": 0.27,
    "lon": 0.59
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "SP2ROC-41",
   "flight_id": "SP2ROC-41_2026-01-25",
   "payload_type": "WSPR",
   "seed_time": "2026-08-10 04:48:00",
   "seed_lat": 47.60417,
   "seed_lon": -179.45833,
   "seed_alt_m": 16040.0,
   "seed_age_h": 12.53,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-17 11:45:00",
    "lat": 33.51818,
    "lon": -159.85765,
    "alt_m": 16335.4
   },
   "member_spread_deg": {
    "lat": 54.26,
    "lon": 325.57
   },
   "member_spread_now_deg": {
    "lat": 2.23,
    "lon": 359.71
   },
   "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": 238.47,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-17 11:45:00",
    "lat": 52.69774,
    "lon": -75.08074,
    "alt_m": 12926.7
   },
   "member_spread_deg": {
    "lat": 22.43,
    "lon": 344.06
   },
   "member_spread_now_deg": {
    "lat": 22.09,
    "lon": 336.01
   },
   "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": 157.24,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-17 11:30:00",
    "lat": 50.76525,
    "lon": 100.99452,
    "alt_m": 12693.0
   },
   "member_spread_deg": {
    "lat": 28.46,
    "lon": 247.68
   },
   "member_spread_now_deg": {
    "lat": 23.51,
    "lon": 331.78
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "VE3VRO-36",
   "flight_id": "VE3VRO-36_2026-07-30",
   "payload_type": "WSPR",
   "seed_time": "2026-08-10 10:36:00",
   "seed_lat": 44.64583,
   "seed_lon": 102.29167,
   "seed_alt_m": 13110.0,
   "seed_age_h": 6.73,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-17 11:30:00",
    "lat": 42.0622,
    "lon": -105.31751,
    "alt_m": 13502.6
   },
   "member_spread_deg": {
    "lat": 30.1,
    "lon": 313.9
   },
   "member_spread_now_deg": {
    "lat": 1.48,
    "lon": 1.14
   },
   "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": 252.77,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-17 11:30:00",
    "lat": 1.27905,
    "lon": 34.98046,
    "alt_m": 12689.2
   },
   "member_spread_deg": {
    "lat": 39.79,
    "lon": 214.79
   },
   "member_spread_now_deg": {
    "lat": 23.98,
    "lon": 190.77
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "ZS6SRC-39",
   "flight_id": "ZS6SRC-39_2026-08-05",
   "payload_type": "WSPR",
   "seed_time": "2026-08-10 06:11:00",
   "seed_lat": -23.0,
   "seed_lon": 114.875,
   "seed_alt_m": 15730.0,
   "seed_age_h": 11.15,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-17 11:45:00",
    "lat": -20.17583,
    "lon": -105.85173,
    "alt_m": 15662.7
   },
   "member_spread_deg": {
    "lat": 31.74,
    "lon": 336.32
   },
   "member_spread_now_deg": {
    "lat": 2.35,
    "lon": 15.85
   },
   "display_as": "track",
   "display_reason": "fresh"
  }
 ]
}