{
 "generated_utc": "2026-08-14T05:27:25Z",
 "gfs_cycle_utc": "2026-08-14T00:00:00Z",
 "model": {
  "source": "NCEP GFS 0.50 degree",
  "vertical_coordinate": "constant density (isopycnic)",
  "horizon_hours": 485.0,
  "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_20260814_00Z.csv.gz",
  "trajectories_geojson_gz": "PBA_forecast_20260814_00Z.geojson.gz"
 },
 "counts": {
  "flights": 24,
  "members": 9,
  "rows": 97497
 },
 "flights": [
  {
   "callsign": "AG6NS-23",
   "flight_id": "AG6NS-23_2026-02-07",
   "payload_type": "WSPR",
   "seed_time": "2026-08-13 18:18:40",
   "seed_lat": -52.3125,
   "seed_lon": -39.20832,
   "seed_alt_m": 12270.0,
   "seed_age_h": 11.02,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-20 23:45:00",
    "lat": -50.31509,
    "lon": -84.10432,
    "alt_m": 12738.9
   },
   "member_spread_deg": {
    "lat": 14.53,
    "lon": 46.19
   },
   "member_spread_now_deg": {
    "lat": 1.43,
    "lon": 5.75
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS53",
   "flight_id": "BSS53_2026-03-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-13 08:30:18",
   "seed_lat": 57.54167,
   "seed_lon": 19.20833,
   "seed_alt_m": 12870.0,
   "seed_age_h": 20.83,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-20 23:30:00",
    "lat": 68.91479,
    "lon": -157.48723,
    "alt_m": 12321.2
   },
   "member_spread_deg": {
    "lat": 22.5,
    "lon": 247.91
   },
   "member_spread_now_deg": {
    "lat": 3.15,
    "lon": 9.78
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS54",
   "flight_id": "BSS54_2026-07-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-14 02:55:18",
   "seed_lat": 49.58333,
   "seed_lon": 145.16667,
   "seed_alt_m": 14330.0,
   "seed_age_h": 2.41,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-21 02:30:00",
    "lat": 56.51436,
    "lon": -110.54235,
    "alt_m": 13995.4
   },
   "member_spread_deg": {
    "lat": 22.52,
    "lon": 307.77
   },
   "member_spread_now_deg": {
    "lat": 0.54,
    "lon": 0.9
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-23",
   "flight_id": "DG2GG-23_2026-05-23",
   "payload_type": "WSPR",
   "seed_time": "2026-08-13 16:04:00",
   "seed_lat": 52.14583,
   "seed_lon": 5.41667,
   "seed_alt_m": 12990.0,
   "seed_age_h": 13.27,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-20 23:30:00",
    "lat": 55.65501,
    "lon": -160.28259,
    "alt_m": 12851.1
   },
   "member_spread_deg": {
    "lat": 10.65,
    "lon": 337.41
   },
   "member_spread_now_deg": {
    "lat": 0.83,
    "lon": 1.21
   },
   "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": 101.03,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-20 23:45:00",
    "lat": 4.10082,
    "lon": -74.9871,
    "alt_m": 14075.9
   },
   "member_spread_deg": {
    "lat": 36.04,
    "lon": 140.64
   },
   "member_spread_now_deg": {
    "lat": 28.57,
    "lon": 50.65
   },
   "display_as": "region",
   "display_reason": "seed_age"
  },
  {
   "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": 240.38,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-20 23:30:00",
    "lat": 36.35066,
    "lon": 4.35653,
    "alt_m": 13463.4
   },
   "member_spread_deg": {
    "lat": 76.72,
    "lon": 213.96
   },
   "member_spread_now_deg": {
    "lat": 67.74,
    "lon": 237.85
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "DG2GG-30",
   "flight_id": "DG2GG-30_2026-08-07",
   "payload_type": "WSPR",
   "seed_time": "2026-08-14 03:01:00",
   "seed_lat": 48.25,
   "seed_lon": -163.70833,
   "seed_alt_m": 12760.0,
   "seed_age_h": 2.32,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-21 02:30:00",
    "lat": 56.14823,
    "lon": 32.49132,
    "alt_m": 12337.0
   },
   "member_spread_deg": {
    "lat": 12.45,
    "lon": 195.22
   },
   "member_spread_now_deg": {
    "lat": 0.8,
    "lon": 1.95
   },
   "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": 60.78,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-20 23:30:00",
    "lat": 69.87421,
    "lon": 168.25616,
    "alt_m": 11829.8
   },
   "member_spread_deg": {
    "lat": 31.01,
    "lon": 328.56
   },
   "member_spread_now_deg": {
    "lat": 18.1,
    "lon": 7.98
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "EI6BFW-18",
   "flight_id": "EI6BFW-18_2026-07-25",
   "payload_type": "WSPR",
   "seed_time": "2026-08-14 01:53:00",
   "seed_lat": 69.41667,
   "seed_lon": -134.375,
   "seed_alt_m": 12640.0,
   "seed_age_h": 3.45,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-21 01:30:00",
    "lat": 54.46201,
    "lon": -7.28029,
    "alt_m": 12441.5
   },
   "member_spread_deg": {
    "lat": 7.68,
    "lon": 122.88
   },
   "member_spread_now_deg": {
    "lat": 1.6,
    "lon": 5.01
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "K5NOT-11",
   "flight_id": "K5NOT-11_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-14 00:45:37",
   "seed_lat": 24.99994,
   "seed_lon": -130.04167,
   "seed_alt_m": 13360.0,
   "seed_age_h": 4.57,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-21 00:15:00",
    "lat": 28.11586,
    "lon": -101.67429,
    "alt_m": 13440.8
   },
   "member_spread_deg": {
    "lat": 30.38,
    "lon": 174.1
   },
   "member_spread_now_deg": {
    "lat": 1.71,
    "lon": 1.34
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KC3LBR-449",
   "flight_id": "KC3LBR-449_2026-07-06",
   "payload_type": "WSPR",
   "seed_time": "2026-08-13 15:22:33",
   "seed_lat": 50.66667,
   "seed_lon": 25.54167,
   "seed_alt_m": 13700.0,
   "seed_age_h": 13.96,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-20 23:30:00",
    "lat": 56.1545,
    "lon": 100.39661,
    "alt_m": 13484.6
   },
   "member_spread_deg": {
    "lat": 15.57,
    "lon": 321.93
   },
   "member_spread_now_deg": {
    "lat": 0.34,
    "lon": 8.0
   },
   "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": 41.66,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-20 23:45:00",
    "lat": 56.41195,
    "lon": 90.23308,
    "alt_m": 12334.7
   },
   "member_spread_deg": {
    "lat": 12.61,
    "lon": 256.06
   },
   "member_spread_now_deg": {
    "lat": 9.14,
    "lon": 24.97
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KD7FXO-1",
   "flight_id": "KD7FXO-1_2026-08-02",
   "payload_type": "WSPR",
   "seed_time": "2026-08-13 17:37:30",
   "seed_lat": 43.10417,
   "seed_lon": -0.58333,
   "seed_alt_m": 13040.0,
   "seed_age_h": 11.71,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-20 23:30:00",
    "lat": 35.99192,
    "lon": -174.88538,
    "alt_m": 13042.8
   },
   "member_spread_deg": {
    "lat": 26.7,
    "lon": 336.52
   },
   "member_spread_now_deg": {
    "lat": 1.7,
    "lon": 2.76
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KE8RES-8",
   "flight_id": "KE8RES-8_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-13 20:31:00",
   "seed_lat": 52.66667,
   "seed_lon": -65.0,
   "seed_alt_m": 12140.0,
   "seed_age_h": 8.82,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-20 23:30:00",
    "lat": 73.97755,
    "lon": -45.31063,
    "alt_m": 11975.1
   },
   "member_spread_deg": {
    "lat": 25.59,
    "lon": 134.71
   },
   "member_spread_now_deg": {
    "lat": 0.56,
    "lon": 1.3
   },
   "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": 8.15,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-20 23:45:00",
    "lat": 46.39224,
    "lon": -19.24464,
    "alt_m": 11142.4
   },
   "member_spread_deg": {
    "lat": 20.33,
    "lon": 125.6
   },
   "member_spread_now_deg": {
    "lat": 6.61,
    "lon": 2.24
   },
   "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": 294.41,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-20 23:30:00",
    "lat": -2.71297,
    "lon": -110.22521,
    "alt_m": 12362.7
   },
   "member_spread_deg": {
    "lat": 38.09,
    "lon": 184.34
   },
   "member_spread_now_deg": {
    "lat": 20.81,
    "lon": 62.99
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "KI6DS-11",
   "flight_id": "KI6DS-11_2026-02-03",
   "payload_type": "WSPR",
   "seed_time": "2026-08-14 04:55:45",
   "seed_lat": 78.12495,
   "seed_lon": 84.50002,
   "seed_alt_m": 13240.0,
   "seed_age_h": 0.41,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-21 05:00:00",
    "lat": 67.41524,
    "lon": -155.03384,
    "alt_m": 12919.9
   },
   "member_spread_deg": {
    "lat": 30.5,
    "lon": 340.1
   },
   "member_spread_now_deg": {
    "lat": 0.03,
    "lon": 0.58
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "SP2ROC-41",
   "flight_id": "SP2ROC-41_2026-01-25",
   "payload_type": "WSPR",
   "seed_time": "2026-08-14 04:48:30",
   "seed_lat": 21.125,
   "seed_lon": 174.58333,
   "seed_alt_m": 16500.0,
   "seed_age_h": 0.53,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-21 04:15:00",
    "lat": 8.41189,
    "lon": 61.57376,
    "alt_m": 16519.0
   },
   "member_spread_deg": {
    "lat": 38.51,
    "lon": 48.79
   },
   "member_spread_now_deg": {
    "lat": 0.19,
    "lon": 0.13
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "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": 322.47,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-20 23:45:00",
    "lat": 32.90097,
    "lon": -135.75043,
    "alt_m": 13576.2
   },
   "member_spread_deg": {
    "lat": 49.42,
    "lon": 231.85
   },
   "member_spread_now_deg": {
    "lat": 14.68,
    "lon": 354.17
   },
   "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": 241.24,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-20 23:30:00",
    "lat": 37.51581,
    "lon": -173.01775,
    "alt_m": 13034.2
   },
   "member_spread_deg": {
    "lat": 37.96,
    "lon": 337.43
   },
   "member_spread_now_deg": {
    "lat": 39.15,
    "lon": 236.69
   },
   "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 22:41:00",
   "seed_lat": 45.875,
   "seed_lon": 142.66667,
   "seed_alt_m": 13600.0,
   "seed_age_h": 30.65,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-20 23:45:00",
    "lat": 48.01152,
    "lon": -94.82721,
    "alt_m": 13258.1
   },
   "member_spread_deg": {
    "lat": 10.58,
    "lon": 260.46
   },
   "member_spread_now_deg": {
    "lat": 11.84,
    "lon": 14.34
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "W0RBO-12",
   "flight_id": "W0RBO-12_2026-05-02",
   "payload_type": "WSPR",
   "seed_time": "2026-08-14 02:05:23",
   "seed_lat": 54.52078,
   "seed_lon": 141.29169,
   "seed_alt_m": 13630.0,
   "seed_age_h": 3.24,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-21 01:30:00",
    "lat": 67.06888,
    "lon": -133.52237,
    "alt_m": 12958.6
   },
   "member_spread_deg": {
    "lat": 28.18,
    "lon": 62.95
   },
   "member_spread_now_deg": {
    "lat": 2.12,
    "lon": 3.3
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "ZS6SRC-37",
   "flight_id": "ZS6SRC-37_2026-07-31",
   "payload_type": "WSPR",
   "seed_time": "2026-08-14 02:59:00",
   "seed_lat": -24.0625,
   "seed_lon": 115.91667,
   "seed_alt_m": 12240.0,
   "seed_age_h": 2.35,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-21 02:30:00",
    "lat": -12.06955,
    "lon": -20.96029,
    "alt_m": 12589.3
   },
   "member_spread_deg": {
    "lat": 32.5,
    "lon": 267.59
   },
   "member_spread_now_deg": {
    "lat": 0.54,
    "lon": 1.14
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "ZS6SRC-39",
   "flight_id": "ZS6SRC-39_2026-08-05",
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   "seed_time": "2026-08-12 06:21:00",
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   "seed_lon": 146.45833,
   "seed_alt_m": 15900.0,
   "seed_age_h": 46.98,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-20 23:45:00",
    "lat": -12.15418,
    "lon": -29.6319,
    "alt_m": 16016.9
   },
   "member_spread_deg": {
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   },
   "member_spread_now_deg": {
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    "lon": 353.99
   },
   "display_as": "region",
   "display_reason": "member_spread"
  }
 ]
}