{
 "generated_utc": "2026-08-25T05:27:13Z",
 "gfs_cycle_utc": "2026-08-25T00:00:00Z",
 "model": {
  "source": "NCEP GFS 0.50 degree",
  "vertical_coordinate": "constant density (isopycnic)",
  "horizon_hours": 473.5,
  "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_20260825_00Z.csv.gz",
  "trajectories_geojson_gz": "PBA_forecast_20260825_00Z.geojson.gz"
 },
 "counts": {
  "flights": 21,
  "members": 9,
  "rows": 88443
 },
 "flights": [
  {
   "callsign": "AG6NS-23",
   "flight_id": "AG6NS-23_2026-02-07",
   "payload_type": "WSPR",
   "seed_time": "2026-08-25 04:43:40",
   "seed_lat": -64.52083,
   "seed_lon": 132.54168,
   "seed_alt_m": 12600.0,
   "seed_age_h": 0.61,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-09-01 04:15:00",
    "lat": -67.66433,
    "lon": 148.32722,
    "alt_m": 12121.0
   },
   "member_spread_deg": {
    "lat": 15.07,
    "lon": 178.43
   },
   "member_spread_now_deg": {
    "lat": 0.13,
    "lon": 0.05
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS54",
   "flight_id": "BSS54_2026-07-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-24 16:47:17",
   "seed_lat": 57.39583,
   "seed_lon": -60.0,
   "seed_alt_m": 13900.0,
   "seed_age_h": 12.55,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-31 23:45:00",
    "lat": 47.09304,
    "lon": 158.87424,
    "alt_m": 13738.8
   },
   "member_spread_deg": {
    "lat": 14.94,
    "lon": 335.11
   },
   "member_spread_now_deg": {
    "lat": 13.58,
    "lon": 16.9
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-23",
   "flight_id": "DG2GG-23_2026-05-23",
   "payload_type": "WSPR",
   "seed_time": "2026-08-24 22:09:00",
   "seed_lat": 46.33333,
   "seed_lon": -102.45833,
   "seed_alt_m": 12920.0,
   "seed_age_h": 7.18,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-31 23:45:00",
    "lat": 43.45327,
    "lon": 89.21238,
    "alt_m": 12767.9
   },
   "member_spread_deg": {
    "lat": 18.42,
    "lon": 62.99
   },
   "member_spread_now_deg": {
    "lat": 0.42,
    "lon": 3.85
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-30",
   "flight_id": "DG2GG-30_2026-08-07",
   "payload_type": "WSPR",
   "seed_time": "2026-08-25 04:36:00",
   "seed_lat": 54.0625,
   "seed_lon": 148.41667,
   "seed_alt_m": 12360.0,
   "seed_age_h": 0.73,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-09-01 04:00:00",
    "lat": 60.95575,
    "lon": -10.63277,
    "alt_m": 12078.0
   },
   "member_spread_deg": {
    "lat": 20.38,
    "lon": 214.43
   },
   "member_spread_now_deg": {
    "lat": 0.04,
    "lon": 0.34
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-31",
   "flight_id": "DG2GG-31_2026-08-13",
   "payload_type": "WSPR",
   "seed_time": "2026-08-25 01:42:00",
   "seed_lat": 36.39583,
   "seed_lon": -131.75,
   "seed_alt_m": 13340.0,
   "seed_age_h": 3.63,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-09-01 01:15:00",
    "lat": 52.40618,
    "lon": 43.53831,
    "alt_m": 13037.3
   },
   "member_spread_deg": {
    "lat": 22.02,
    "lon": 112.45
   },
   "member_spread_now_deg": {
    "lat": 0.34,
    "lon": 0.59
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DN3LEO-13",
   "flight_id": "DN3LEO-13_2026-04-12",
   "payload_type": "WSPR",
   "seed_time": "2026-08-24 22:23:00",
   "seed_lat": 79.125,
   "seed_lon": -107.5,
   "seed_alt_m": 11860.0,
   "seed_age_h": 6.95,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-31 23:30:00",
    "lat": 53.6424,
    "lon": 75.2691,
    "alt_m": 12039.0
   },
   "member_spread_deg": {
    "lat": 27.36,
    "lon": 189.66
   },
   "member_spread_now_deg": {
    "lat": 3.03,
    "lon": 12.85
   },
   "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": 15.12,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-31 23:45:00",
    "lat": 52.99946,
    "lon": 134.21818,
    "alt_m": 12869.4
   },
   "member_spread_deg": {
    "lat": 24.74,
    "lon": 325.59
   },
   "member_spread_now_deg": {
    "lat": 8.61,
    "lon": 12.58
   },
   "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": 224.49,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-31 23:45:00",
    "lat": 27.64247,
    "lon": -40.50131,
    "alt_m": 13317.8
   },
   "member_spread_deg": {
    "lat": 41.29,
    "lon": 267.91
   },
   "member_spread_now_deg": {
    "lat": 38.32,
    "lon": 114.94
   },
   "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 04:57:04",
   "seed_lat": 60.9375,
   "seed_lon": -168.08333,
   "seed_alt_m": 13300.0,
   "seed_age_h": 0.38,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-09-01 05:00:00",
    "lat": 52.87391,
    "lon": 13.70909,
    "alt_m": 13138.4
   },
   "member_spread_deg": {
    "lat": 39.66,
    "lon": 209.11
   },
   "member_spread_now_deg": {
    "lat": 0.26,
    "lon": 0.56
   },
   "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": 305.66,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-31 23:45:00",
    "lat": 54.54764,
    "lon": 131.02258,
    "alt_m": 12709.0
   },
   "member_spread_deg": {
    "lat": 42.65,
    "lon": 301.71
   },
   "member_spread_now_deg": {
    "lat": 29.77,
    "lon": 295.3
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "KC7RW-3",
   "flight_id": "KC7RW-3_2026-08-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-24 16:19:00",
   "seed_lat": 25.33333,
   "seed_lon": -28.04167,
   "seed_alt_m": 12830.0,
   "seed_age_h": 13.02,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-31 23:45:00",
    "lat": 42.61676,
    "lon": 134.6465,
    "alt_m": 12493.9
   },
   "member_spread_deg": {
    "lat": 12.89,
    "lon": 158.34
   },
   "member_spread_now_deg": {
    "lat": 2.13,
    "lon": 4.37
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KD7FXO-1",
   "flight_id": "KD7FXO-1_2026-08-02",
   "payload_type": "WSPR",
   "seed_time": "2026-08-25 04:10:00",
   "seed_lat": 30.70833,
   "seed_lon": -167.58333,
   "seed_alt_m": 13010.0,
   "seed_age_h": 1.17,
   "float_reliable": false,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-09-01 03:45:00",
    "lat": 32.16393,
    "lon": -65.294,
    "alt_m": 12922.5
   },
   "member_spread_deg": {
    "lat": 28.82,
    "lon": 75.7
   },
   "member_spread_now_deg": {
    "lat": 0.41,
    "lon": 0.21
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KE8RES-8",
   "flight_id": "KE8RES-8_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-23 23:01:00",
   "seed_lat": 73.33333,
   "seed_lon": -150.25,
   "seed_alt_m": 11900.0,
   "seed_age_h": 30.32,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-31 23:30:00",
    "lat": 72.91017,
    "lon": 75.69604,
    "alt_m": 12183.9
   },
   "member_spread_deg": {
    "lat": 19.87,
    "lon": 208.65
   },
   "member_spread_now_deg": {
    "lat": 8.83,
    "lon": 176.92
   },
   "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": 272.15,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-31 23:45:00",
    "lat": 18.99773,
    "lon": -21.22239,
    "alt_m": 11189.0
   },
   "member_spread_deg": {
    "lat": 41.21,
    "lon": 358.37
   },
   "member_spread_now_deg": {
    "lat": 38.74,
    "lon": 143.31
   },
   "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": 51.57,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-31 23:45:00",
    "lat": 74.61608,
    "lon": -46.57481,
    "alt_m": 12768.6
   },
   "member_spread_deg": {
    "lat": 14.51,
    "lon": 249.95
   },
   "member_spread_now_deg": {
    "lat": 8.12,
    "lon": 104.21
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "KJ4AWK-1",
   "flight_id": "KJ4AWK-1_2026-08-22",
   "payload_type": "APRS",
   "seed_time": "2026-08-24 16:57:38",
   "seed_lat": 35.22266,
   "seed_lon": -24.3055,
   "seed_alt_m": 13436.0,
   "seed_age_h": 12.37,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-31 23:30:00",
    "lat": 53.5234,
    "lon": -135.60279,
    "alt_m": 12796.2
   },
   "member_spread_deg": {
    "lat": 19.82,
    "lon": 330.49
   },
   "member_spread_now_deg": {
    "lat": 1.45,
    "lon": 2.75
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "SP2ROC-41",
   "flight_id": "SP2ROC-41_2026-01-25",
   "payload_type": "WSPR",
   "seed_time": "2026-08-24 16:03:30",
   "seed_lat": 18.77083,
   "seed_lon": 0.75,
   "seed_alt_m": 16715.0,
   "seed_age_h": 13.28,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-31 23:30:00",
    "lat": 46.43054,
    "lon": 58.57917,
    "alt_m": 15946.7
   },
   "member_spread_deg": {
    "lat": 52.41,
    "lon": 104.78
   },
   "member_spread_now_deg": {
    "lat": 0.67,
    "lon": 0.94
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "VE3VRO-36",
   "flight_id": "VE3VRO-36_2026-07-30",
   "payload_type": "WSPR",
   "seed_time": "2026-08-24 18:41:00",
   "seed_lat": 38.54167,
   "seed_lon": -28.04167,
   "seed_alt_m": 13530.0,
   "seed_age_h": 10.65,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-31 23:45:00",
    "lat": 58.50871,
    "lon": -166.84613,
    "alt_m": 13144.0
   },
   "member_spread_deg": {
    "lat": 21.18,
    "lon": 342.1
   },
   "member_spread_now_deg": {
    "lat": 0.49,
    "lon": 4.11
   },
   "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": 176.35,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-31 23:30:00",
    "lat": -17.68603,
    "lon": 10.6634,
    "alt_m": 12643.9
   },
   "member_spread_deg": {
    "lat": 38.85,
    "lon": 181.93
   },
   "member_spread_now_deg": {
    "lat": 10.11,
    "lon": 309.86
   },
   "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": 310.98,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-31 23:45:00",
    "lat": -31.971,
    "lon": 140.96971,
    "alt_m": 15866.9
   },
   "member_spread_deg": {
    "lat": 36.97,
    "lon": 232.49
   },
   "member_spread_now_deg": {
    "lat": 33.46,
    "lon": 252.29
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "ZS6WBT-1",
   "flight_id": "ZS6WBT-1_2026-08-19",
   "payload_type": "WSPR",
   "seed_time": "2026-08-25 04:31:00",
   "seed_lat": -26.5625,
   "seed_lon": 151.20833,
   "seed_alt_m": 15580.0,
   "seed_age_h": 0.82,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-09-01 04:00:00",
    "lat": -28.14158,
    "lon": -28.00069,
    "alt_m": 15531.8
   },
   "member_spread_deg": {
    "lat": 51.08,
    "lon": 76.99
   },
   "member_spread_now_deg": {
    "lat": 0.1,
    "lon": 0.88
   },
   "display_as": "track",
   "display_reason": "fresh"
  }
 ]
}