{
 "generated_utc": "2026-08-22T17:27:01Z",
 "gfs_cycle_utc": "2026-08-22T12:00:00Z",
 "model": {
  "source": "NCEP GFS 0.50 degree",
  "vertical_coordinate": "constant density (isopycnic)",
  "horizon_hours": 467.5,
  "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_20260822_12Z.csv.gz",
  "trajectories_geojson_gz": "PBA_forecast_20260822_12Z.geojson.gz"
 },
 "counts": {
  "flights": 23,
  "members": 9,
  "rows": 94095
 },
 "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": 3.61,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 13:15:00",
    "lat": -66.78562,
    "lon": 21.2007,
    "alt_m": 12202.6
   },
   "member_spread_deg": {
    "lat": 35.81,
    "lon": 290.96
   },
   "member_spread_now_deg": {
    "lat": 0.64,
    "lon": 5.69
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS53",
   "flight_id": "BSS53_2026-03-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-22 16:32:47",
   "seed_lat": 80.3125,
   "seed_lon": -113.79167,
   "seed_alt_m": 12300.0,
   "seed_age_h": 0.79,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-29 16:00:00",
    "lat": 54.20834,
    "lon": 58.81395,
    "alt_m": 12431.0
   },
   "member_spread_deg": {
    "lat": 19.78,
    "lon": 83.52
   },
   "member_spread_now_deg": {
    "lat": 0.16,
    "lon": 0.8
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS54",
   "flight_id": "BSS54_2026-07-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-22 16:55:18",
   "seed_lat": 43.75,
   "seed_lon": -93.625,
   "seed_alt_m": 13980.0,
   "seed_age_h": 0.41,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-29 17:00:00",
    "lat": 46.79707,
    "lon": 55.41113,
    "alt_m": 13890.7
   },
   "member_spread_deg": {
    "lat": 24.69,
    "lon": 162.91
   },
   "member_spread_now_deg": {
    "lat": 0.39,
    "lon": 0.26
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-23",
   "flight_id": "DG2GG-23_2026-05-23",
   "payload_type": "WSPR",
   "seed_time": "2026-08-22 02:46:30",
   "seed_lat": 40.16667,
   "seed_lon": -166.20833,
   "seed_alt_m": 12920.0,
   "seed_age_h": 14.56,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 11:45:00",
    "lat": 51.73276,
    "lon": 25.62574,
    "alt_m": 12704.1
   },
   "member_spread_deg": {
    "lat": 29.05,
    "lon": 108.17
   },
   "member_spread_now_deg": {
    "lat": 1.54,
    "lon": 7.42
   },
   "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": 305.03,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-29 11:45:00",
    "lat": -9.80255,
    "lon": -19.64093,
    "alt_m": 14013.1
   },
   "member_spread_deg": {
    "lat": 57.49,
    "lon": 241.88
   },
   "member_spread_now_deg": {
    "lat": 53.78,
    "lon": 120.63
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "DG2GG-30",
   "flight_id": "DG2GG-30_2026-08-07",
   "payload_type": "WSPR",
   "seed_time": "2026-08-22 11:26:00",
   "seed_lat": 49.08333,
   "seed_lon": 69.16667,
   "seed_alt_m": 12560.0,
   "seed_age_h": 5.9,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 11:30:00",
    "lat": 70.98795,
    "lon": -68.47771,
    "alt_m": 12492.8
   },
   "member_spread_deg": {
    "lat": 25.58,
    "lon": 115.14
   },
   "member_spread_now_deg": {
    "lat": 1.08,
    "lon": 0.61
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-31",
   "flight_id": "DG2GG-31_2026-08-13",
   "payload_type": "WSPR",
   "seed_time": "2026-08-22 02:17:00",
   "seed_lat": 52.58333,
   "seed_lon": 155.25,
   "seed_alt_m": 13100.0,
   "seed_age_h": 15.05,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 11:45:00",
    "lat": 55.06104,
    "lon": -57.7071,
    "alt_m": 13054.4
   },
   "member_spread_deg": {
    "lat": 16.65,
    "lon": 86.71
   },
   "member_spread_now_deg": {
    "lat": 1.75,
    "lon": 359.28
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "DN3LEO-13",
   "flight_id": "DN3LEO-13_2026-04-12",
   "payload_type": "WSPR",
   "seed_time": "2026-08-22 06:13:00",
   "seed_lat": 68.125,
   "seed_lon": 149.83333,
   "seed_alt_m": 11900.0,
   "seed_age_h": 11.12,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-29 11:45:00",
    "lat": 63.98976,
    "lon": -51.46745,
    "alt_m": 11963.3
   },
   "member_spread_deg": {
    "lat": 27.75,
    "lon": 176.68
   },
   "member_spread_now_deg": {
    "lat": 0.19,
    "lon": 4.34
   },
   "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": 1.45,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 15:30:00",
    "lat": 77.02803,
    "lon": 134.02064,
    "alt_m": 12479.6
   },
   "member_spread_deg": {
    "lat": 22.79,
    "lon": 346.13
   },
   "member_spread_now_deg": {
    "lat": 0.25,
    "lon": 0.08
   },
   "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": 164.49,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 11:45:00",
    "lat": 19.97465,
    "lon": -69.70349,
    "alt_m": 13396.3
   },
   "member_spread_deg": {
    "lat": 51.83,
    "lon": 234.63
   },
   "member_spread_now_deg": {
    "lat": 18.34,
    "lon": 62.15
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "KC3LBR-449",
   "flight_id": "KC3LBR-449_2026-07-06",
   "payload_type": "WSPR",
   "seed_time": "2026-08-22 12:13:33",
   "seed_lat": 62.72917,
   "seed_lon": 114.16667,
   "seed_alt_m": 13210.0,
   "seed_age_h": 5.11,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 11:45:00",
    "lat": 64.39785,
    "lon": -63.87239,
    "alt_m": 13288.1
   },
   "member_spread_deg": {
    "lat": 25.54,
    "lon": 166.38
   },
   "member_spread_now_deg": {
    "lat": 0.4,
    "lon": 1.64
   },
   "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": 245.66,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 11:45:00",
    "lat": 60.52993,
    "lon": 124.95969,
    "alt_m": 12649.4
   },
   "member_spread_deg": {
    "lat": 30.53,
    "lon": 324.63
   },
   "member_spread_now_deg": {
    "lat": 25.02,
    "lon": 297.21
   },
   "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": 2.35,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-29 14:30:00",
    "lat": 42.67987,
    "lon": 73.71439,
    "alt_m": 11477.9
   },
   "member_spread_deg": {
    "lat": 22.37,
    "lon": 136.48
   },
   "member_spread_now_deg": {
    "lat": 0.97,
    "lon": 0.28
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KD7FXO-1",
   "flight_id": "KD7FXO-1_2026-08-02",
   "payload_type": "WSPR",
   "seed_time": "2026-08-22 05:00:00",
   "seed_lat": 41.27083,
   "seed_lon": -175.58333,
   "seed_alt_m": 13040.0,
   "seed_age_h": 12.33,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 11:30:00",
    "lat": 29.6443,
    "lon": -173.95455,
    "alt_m": 13065.5
   },
   "member_spread_deg": {
    "lat": 13.57,
    "lon": 121.66
   },
   "member_spread_now_deg": {
    "lat": 2.92,
    "lon": 1.25
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KE8RES-8",
   "flight_id": "KE8RES-8_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-20 10:01:00",
   "seed_lat": 85.25,
   "seed_lon": 45.875,
   "seed_alt_m": 11960.0,
   "seed_age_h": 55.32,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-29 11:30:00",
    "lat": 56.66707,
    "lon": 69.53971,
    "alt_m": 11875.2
   },
   "member_spread_deg": {
    "lat": 35.91,
    "lon": 282.11
   },
   "member_spread_now_deg": {
    "lat": 4.24,
    "lon": 343.44
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "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": 212.15,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-29 11:45:00",
    "lat": 29.64252,
    "lon": -70.63564,
    "alt_m": 11256.4
   },
   "member_spread_deg": {
    "lat": 46.29,
    "lon": 319.55
   },
   "member_spread_now_deg": {
    "lat": 14.38,
    "lon": 102.49
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "KI6DS-11",
   "flight_id": "KI6DS-11_2026-02-03",
   "payload_type": "WSPR",
   "seed_time": "2026-08-21 23:15:45",
   "seed_lat": 72.08328,
   "seed_lon": -162.83331,
   "seed_alt_m": 12780.0,
   "seed_age_h": 18.07,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 11:45:00",
    "lat": 75.89007,
    "lon": -139.95256,
    "alt_m": 12802.8
   },
   "member_spread_deg": {
    "lat": 8.23,
    "lon": 299.32
   },
   "member_spread_now_deg": {
    "lat": 6.27,
    "lon": 4.48
   },
   "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": 3.03,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 13:45:00",
    "lat": 19.23078,
    "lon": -33.22086,
    "alt_m": 16444.2
   },
   "member_spread_deg": {
    "lat": 19.3,
    "lon": 92.74
   },
   "member_spread_now_deg": {
    "lat": 0.34,
    "lon": 1.16
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "VE3VRO-36",
   "flight_id": "VE3VRO-36_2026-07-30",
   "payload_type": "WSPR",
   "seed_time": "2026-08-22 16:51:00",
   "seed_lat": 43.35417,
   "seed_lon": -94.95833,
   "seed_alt_m": 13280.0,
   "seed_age_h": 0.48,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 16:15:00",
    "lat": 45.63496,
    "lon": 125.06965,
    "alt_m": 12887.4
   },
   "member_spread_deg": {
    "lat": 7.6,
    "lon": 121.21
   },
   "member_spread_now_deg": {
    "lat": 0.37,
    "lon": 0.27
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "W0RBO-12",
   "flight_id": "W0RBO-12_2026-05-02",
   "payload_type": "WSPR",
   "seed_time": "2026-08-22 16:55:23",
   "seed_lat": 57.43745,
   "seed_lon": -89.16664,
   "seed_alt_m": 12980.0,
   "seed_age_h": 0.41,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 17:00:00",
    "lat": 44.75718,
    "lon": 41.03231,
    "alt_m": 13448.3
   },
   "member_spread_deg": {
    "lat": 23.2,
    "lon": 67.83
   },
   "member_spread_now_deg": {
    "lat": 0.16,
    "lon": 0.19
   },
   "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": 116.35,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-29 11:30:00",
    "lat": -19.6961,
    "lon": -40.32935,
    "alt_m": 12571.0
   },
   "member_spread_deg": {
    "lat": 42.99,
    "lon": 115.84
   },
   "member_spread_now_deg": {
    "lat": 18.12,
    "lon": 141.57
   },
   "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": 250.98,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-29 11:45:00",
    "lat": -25.88525,
    "lon": 120.42013,
    "alt_m": 15777.9
   },
   "member_spread_deg": {
    "lat": 30.77,
    "lon": 244.77
   },
   "member_spread_now_deg": {
    "lat": 22.52,
    "lon": 188.29
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "ZS6WBT-1",
   "flight_id": "ZS6WBT-1_2026-08-19",
   "payload_type": "WSPR",
   "seed_time": "2026-08-22 09:41:00",
   "seed_lat": -27.0625,
   "seed_lon": 95.04167,
   "seed_alt_m": 15530.0,
   "seed_age_h": 7.65,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-29 11:45:00",
    "lat": -27.60794,
    "lon": -57.85766,
    "alt_m": 15255.5
   },
   "member_spread_deg": {
    "lat": 21.56,
    "lon": 57.4
   },
   "member_spread_now_deg": {
    "lat": 1.32,
    "lon": 8.19
   },
   "display_as": "track",
   "display_reason": "fresh"
  }
 ]
}