{
 "generated_utc": "2026-09-05T05:26:22Z",
 "gfs_cycle_utc": "2026-09-05T00:00:00Z",
 "model": {
  "source": "NCEP GFS 0.50 degree",
  "vertical_coordinate": "constant density (isopycnic)",
  "horizon_hours": 441.5,
  "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_20260905_00Z.csv.gz",
  "trajectories_geojson_gz": "PBA_forecast_20260905_00Z.geojson.gz"
 },
 "counts": {
  "flights": 18,
  "members": 9,
  "rows": 78876
 },
 "flights": [
  {
   "callsign": "AG6NS-23",
   "flight_id": "AG6NS-23_2026-02-07",
   "payload_type": "WSPR",
   "seed_time": "2026-08-28 16:13:40",
   "seed_lat": -64.54167,
   "seed_lon": -17.12499,
   "seed_alt_m": 11900.0,
   "seed_age_h": 181.11,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-09-11 23:45:00",
    "lat": -57.75555,
    "lon": -99.2096,
    "alt_m": 12265.0
   },
   "member_spread_deg": {
    "lat": 29.67,
    "lon": 290.47
   },
   "member_spread_now_deg": {
    "lat": 26.72,
    "lon": 65.45
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "BSS54",
   "flight_id": "BSS54_2026-07-09",
   "payload_type": "WSPR",
   "seed_time": "2026-09-05 00:17:49",
   "seed_lat": 40.33333,
   "seed_lon": -102.5,
   "seed_alt_m": 14550.0,
   "seed_age_h": 5.04,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-09-11 23:45:00",
    "lat": 39.35471,
    "lon": -21.56939,
    "alt_m": 14511.9
   },
   "member_spread_deg": {
    "lat": 29.09,
    "lon": 129.05
   },
   "member_spread_now_deg": {
    "lat": 0.89,
    "lon": 2.55
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-23",
   "flight_id": "DG2GG-23_2026-05-23",
   "payload_type": "WSPR",
   "seed_time": "2026-08-25 21:29:00",
   "seed_lat": 33.10417,
   "seed_lon": -84.75,
   "seed_alt_m": 13050.0,
   "seed_age_h": 247.85,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-09-11 23:30:00",
    "lat": 5.04932,
    "lon": -100.84443,
    "alt_m": 13154.7
   },
   "member_spread_deg": {
    "lat": 22.93,
    "lon": 89.12
   },
   "member_spread_now_deg": {
    "lat": 19.26,
    "lon": 50.15
   },
   "display_as": "region",
   "display_reason": "seed_age"
  },
  {
   "callsign": "DG2GG-30",
   "flight_id": "DG2GG-30_2026-08-07",
   "payload_type": "WSPR",
   "seed_time": "2026-09-05 04:41:00",
   "seed_lat": 86.0,
   "seed_lon": 110.20833,
   "seed_alt_m": 11660.0,
   "seed_age_h": 0.65,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-09-12 04:15:00",
    "lat": 87.34798,
    "lon": 18.59167,
    "alt_m": 11669.7
   },
   "member_spread_deg": {
    "lat": 17.55,
    "lon": 217.26
   },
   "member_spread_now_deg": {
    "lat": 0.05,
    "lon": 0.3
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-31",
   "flight_id": "DG2GG-31_2026-08-13",
   "payload_type": "WSPR",
   "seed_time": "2026-09-05 04:57:00",
   "seed_lat": 41.95833,
   "seed_lon": 140.83333,
   "seed_alt_m": 13040.0,
   "seed_age_h": 0.38,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-09-12 05:00:00",
    "lat": 49.99932,
    "lon": -61.80075,
    "alt_m": 12478.7
   },
   "member_spread_deg": {
    "lat": 46.05,
    "lon": 63.69
   },
   "member_spread_now_deg": {
    "lat": 0.05,
    "lon": 0.12
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DN3LEO-13",
   "flight_id": "DN3LEO-13_2026-04-12",
   "payload_type": "WSPR",
   "seed_time": "2026-08-31 09:53:00",
   "seed_lat": 62.54167,
   "seed_lon": 91.41667,
   "seed_alt_m": 11930.0,
   "seed_age_h": 115.45,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-09-11 23:30:00",
    "lat": 49.51522,
    "lon": -117.13281,
    "alt_m": 12265.9
   },
   "member_spread_deg": {
    "lat": 38.79,
    "lon": 306.94
   },
   "member_spread_now_deg": {
    "lat": 33.04,
    "lon": 326.92
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "DO3GU-47",
   "flight_id": "DO3GU-47_2026-09-03",
   "payload_type": "WSPR",
   "seed_time": "2026-09-04 13:23:25",
   "seed_lat": 40.625,
   "seed_lon": 28.375,
   "seed_alt_m": 13960.0,
   "seed_age_h": 15.94,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-09-11 23:30:00",
    "lat": 48.02946,
    "lon": -80.38015,
    "alt_m": 13984.6
   },
   "member_spread_deg": {
    "lat": 29.8,
    "lon": 102.42
   },
   "member_spread_now_deg": {
    "lat": 2.32,
    "lon": 7.38
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "EI6BFW-18",
   "flight_id": "EI6BFW-18_2026-07-25",
   "payload_type": "WSPR",
   "seed_time": "2026-08-24 14:13:00",
   "seed_lat": 65.52083,
   "seed_lon": 37.33333,
   "seed_alt_m": 12490.0,
   "seed_age_h": 279.12,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-09-11 23:45:00",
    "lat": 23.6865,
    "lon": -53.22027,
    "alt_m": 13510.5
   },
   "member_spread_deg": {
    "lat": 42.01,
    "lon": 255.68
   },
   "member_spread_now_deg": {
    "lat": 20.89,
    "lon": 264.39
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "KC3LBR-449",
   "flight_id": "KC3LBR-449_2026-07-06",
   "payload_type": "WSPR",
   "seed_time": "2026-08-25 06:33:48",
   "seed_lat": 61.6875,
   "seed_lon": -165.70833,
   "seed_alt_m": 13200.0,
   "seed_age_h": 262.77,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-09-11 23:30:00",
    "lat": 50.69802,
    "lon": -86.3136,
    "alt_m": 13753.3
   },
   "member_spread_deg": {
    "lat": 34.38,
    "lon": 261.58
   },
   "member_spread_now_deg": {
    "lat": 37.68,
    "lon": 165.44
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "KC7RW-3",
   "flight_id": "KC7RW-3_2026-08-20",
   "payload_type": "WSPR",
   "seed_time": "2026-09-03 08:04:00",
   "seed_lat": 37.27083,
   "seed_lon": 133.375,
   "seed_alt_m": 12750.0,
   "seed_age_h": 45.27,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-09-11 23:30:00",
    "lat": 7.82268,
    "lon": 128.9849,
    "alt_m": 12871.9
   },
   "member_spread_deg": {
    "lat": 34.31,
    "lon": 321.01
   },
   "member_spread_now_deg": {
    "lat": 4.18,
    "lon": 353.38
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "KD7FXO-1",
   "flight_id": "KD7FXO-1_2026-08-02",
   "payload_type": "WSPR",
   "seed_time": "2026-09-04 19:05:00",
   "seed_lat": 25.79167,
   "seed_lon": -32.75,
   "seed_alt_m": 13040.0,
   "seed_age_h": 10.25,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-09-11 23:30:00",
    "lat": 43.23573,
    "lon": 68.91219,
    "alt_m": 12669.9
   },
   "member_spread_deg": {
    "lat": 13.37,
    "lon": 97.38
   },
   "member_spread_now_deg": {
    "lat": 1.13,
    "lon": 4.37
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KE8RES-8",
   "flight_id": "KE8RES-8_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-09-05 02:36:00",
   "seed_lat": 55.70833,
   "seed_lon": -173.95833,
   "seed_alt_m": 12060.0,
   "seed_age_h": 2.73,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-09-12 02:00:00",
    "lat": 57.01103,
    "lon": 33.48618,
    "alt_m": 12574.6
   },
   "member_spread_deg": {
    "lat": 15.02,
    "lon": 71.22
   },
   "member_spread_now_deg": {
    "lat": 0.15,
    "lon": 0.79
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KI6DS-11",
   "flight_id": "KI6DS-11_2026-02-03",
   "payload_type": "WSPR",
   "seed_time": "2026-09-04 17:05:45",
   "seed_lat": 60.52078,
   "seed_lon": -5.12498,
   "seed_alt_m": 12960.0,
   "seed_age_h": 12.24,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-09-11 23:30:00",
    "lat": 55.73046,
    "lon": 177.92686,
    "alt_m": 12989.3
   },
   "member_spread_deg": {
    "lat": 25.08,
    "lon": 356.95
   },
   "member_spread_now_deg": {
    "lat": 0.88,
    "lon": 0.9
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KJ4AWK-1",
   "flight_id": "KJ4AWK-1_2026-08-22",
   "payload_type": "APRS",
   "seed_time": "2026-08-26 15:51:36",
   "seed_lat": 41.62025,
   "seed_lon": 25.112,
   "seed_alt_m": 13223.0,
   "seed_age_h": 229.47,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-09-11 23:45:00",
    "lat": 30.4132,
    "lon": -25.22193,
    "alt_m": 13362.2
   },
   "member_spread_deg": {
    "lat": 22.42,
    "lon": 146.34
   },
   "member_spread_now_deg": {
    "lat": 14.75,
    "lon": 73.54
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "SP2ROC-41",
   "flight_id": "SP2ROC-41_2026-01-25",
   "payload_type": "WSPR",
   "seed_time": "2026-09-05 03:01:00",
   "seed_lat": 35.79167,
   "seed_lon": -162.375,
   "seed_alt_m": 16200.0,
   "seed_age_h": 2.32,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-09-12 02:30:00",
    "lat": 24.93291,
    "lon": -165.40448,
    "alt_m": 16501.0
   },
   "member_spread_deg": {
    "lat": 32.18,
    "lon": 132.6
   },
   "member_spread_now_deg": {
    "lat": 1.28,
    "lon": 0.44
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "VE3VRO-36",
   "flight_id": "VE3VRO-36_2026-07-30",
   "payload_type": "WSPR",
   "seed_time": "2026-09-05 00:41:00",
   "seed_lat": 40.0,
   "seed_lon": -118.95833,
   "seed_alt_m": 13080.0,
   "seed_age_h": 4.65,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-09-12 00:15:00",
    "lat": 54.33545,
    "lon": 47.43496,
    "alt_m": 13157.4
   },
   "member_spread_deg": {
    "lat": 26.84,
    "lon": 87.39
   },
   "member_spread_now_deg": {
    "lat": 2.42,
    "lon": 2.27
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "W0RBO-12",
   "flight_id": "W0RBO-12_2026-05-02",
   "payload_type": "WSPR",
   "seed_time": "2026-09-04 23:05:23",
   "seed_lat": 65.56245,
   "seed_lon": -134.08331,
   "seed_alt_m": 13180.0,
   "seed_age_h": 6.24,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-09-11 23:30:00",
    "lat": 24.17865,
    "lon": -73.48054,
    "alt_m": 13995.6
   },
   "member_spread_deg": {
    "lat": 34.72,
    "lon": 126.09
   },
   "member_spread_now_deg": {
    "lat": 3.79,
    "lon": 5.64
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "ZS6WBT-1",
   "flight_id": "ZS6WBT-1_2026-08-19",
   "payload_type": "WSPR",
   "seed_time": "2026-09-04 14:41:00",
   "seed_lat": -33.35417,
   "seed_lon": -2.91667,
   "seed_alt_m": 15420.0,
   "seed_age_h": 14.65,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-09-11 23:45:00",
    "lat": -26.38398,
    "lon": 77.29083,
    "alt_m": 15398.8
   },
   "member_spread_deg": {
    "lat": 15.11,
    "lon": 326.33
   },
   "member_spread_now_deg": {
    "lat": 4.43,
    "lon": 4.7
   },
   "display_as": "track",
   "display_reason": "fresh"
  }
 ]
}