{
 "generated_utc": "2026-08-15T17:27:27Z",
 "gfs_cycle_utc": "2026-08-15T12:00:00Z",
 "model": {
  "source": "NCEP GFS 0.50 degree",
  "vertical_coordinate": "constant density (isopycnic)",
  "horizon_hours": 492.5,
  "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_20260815_12Z.csv.gz",
  "trajectories_geojson_gz": "PBA_forecast_20260815_12Z.geojson.gz"
 },
 "counts": {
  "flights": 24,
  "members": 9,
  "rows": 95229
 },
 "flights": [
  {
   "callsign": "AG6NS-23",
   "flight_id": "AG6NS-23_2026-02-07",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 12:53:40",
   "seed_lat": -59.83333,
   "seed_lon": 15.66668,
   "seed_alt_m": 12570.0,
   "seed_age_h": 4.44,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 12:30:00",
    "lat": -51.47097,
    "lon": 36.8283,
    "alt_m": 12292.3
   },
   "member_spread_deg": {
    "lat": 52.03,
    "lon": 285.85
   },
   "member_spread_now_deg": {
    "lat": 1.09,
    "lon": 8.93
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS53",
   "flight_id": "BSS53_2026-03-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 13:36:48",
   "seed_lat": 54.8125,
   "seed_lon": 77.125,
   "seed_alt_m": 12860.0,
   "seed_age_h": 3.72,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 13:00:00",
    "lat": 47.6165,
    "lon": -148.37977,
    "alt_m": 12480.5
   },
   "member_spread_deg": {
    "lat": 34.81,
    "lon": 58.73
   },
   "member_spread_now_deg": {
    "lat": 0.14,
    "lon": 0.46
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS54",
   "flight_id": "BSS54_2026-07-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 00:19:47",
   "seed_lat": 52.1875,
   "seed_lon": 154.5,
   "seed_alt_m": 14180.0,
   "seed_age_h": 17.0,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 11:45:00",
    "lat": 32.52546,
    "lon": -130.93116,
    "alt_m": 14313.9
   },
   "member_spread_deg": {
    "lat": 25.29,
    "lon": 106.75
   },
   "member_spread_now_deg": {
    "lat": 3.47,
    "lon": 4.72
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-23",
   "flight_id": "DG2GG-23_2026-05-23",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 14:29:00",
   "seed_lat": 43.54167,
   "seed_lon": 22.45833,
   "seed_alt_m": 12750.0,
   "seed_age_h": 2.85,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 14:00:00",
    "lat": 64.3325,
    "lon": -153.77201,
    "alt_m": 12453.5
   },
   "member_spread_deg": {
    "lat": 35.09,
    "lon": 15.9
   },
   "member_spread_now_deg": {
    "lat": 0.96,
    "lon": 1.36
   },
   "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": 137.03,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-22 11:45:00",
    "lat": 13.47501,
    "lon": -90.0364,
    "alt_m": 14050.4
   },
   "member_spread_deg": {
    "lat": 35.02,
    "lon": 111.88
   },
   "member_spread_now_deg": {
    "lat": 33.16,
    "lon": 65.99
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "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": 276.38,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 11:30:00",
    "lat": 42.20676,
    "lon": 77.52767,
    "alt_m": 13263.6
   },
   "member_spread_deg": {
    "lat": 86.52,
    "lon": 322.01
   },
   "member_spread_now_deg": {
    "lat": 73.94,
    "lon": 214.74
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "DG2GG-30",
   "flight_id": "DG2GG-30_2026-08-07",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 16:11:00",
   "seed_lat": 36.6875,
   "seed_lon": -127.16667,
   "seed_alt_m": 12880.0,
   "seed_age_h": 1.15,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 15:45:00",
    "lat": 48.74203,
    "lon": 78.07345,
    "alt_m": 12613.3
   },
   "member_spread_deg": {
    "lat": 27.01,
    "lon": 70.64
   },
   "member_spread_now_deg": {
    "lat": 0.18,
    "lon": 0.18
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-31",
   "flight_id": "DG2GG-31_2026-08-13",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 14:52:00",
   "seed_lat": 42.02083,
   "seed_lon": 16.04167,
   "seed_alt_m": 13300.0,
   "seed_age_h": 2.47,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 14:15:00",
    "lat": 41.06945,
    "lon": -163.29311,
    "alt_m": 13363.1
   },
   "member_spread_deg": {
    "lat": 10.92,
    "lon": 22.61
   },
   "member_spread_now_deg": {
    "lat": 0.34,
    "lon": 0.3
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DN3LEO-13",
   "flight_id": "DN3LEO-13_2026-04-12",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 10:43:00",
   "seed_lat": 81.70833,
   "seed_lon": 99.16667,
   "seed_alt_m": 11900.0,
   "seed_age_h": 6.62,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-22 11:45:00",
    "lat": 78.09265,
    "lon": 129.46096,
    "alt_m": 11668.8
   },
   "member_spread_deg": {
    "lat": 24.1,
    "lon": 306.19
   },
   "member_spread_now_deg": {
    "lat": 3.17,
    "lon": 18.79
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "EI6BFW-18",
   "flight_id": "EI6BFW-18_2026-07-25",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 14:13:00",
   "seed_lat": 62.25,
   "seed_lon": -105.41667,
   "seed_alt_m": 12570.0,
   "seed_age_h": 3.12,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 13:45:00",
    "lat": 71.72532,
    "lon": 10.00963,
    "alt_m": 12265.0
   },
   "member_spread_deg": {
    "lat": 22.45,
    "lon": 93.91
   },
   "member_spread_now_deg": {
    "lat": 1.03,
    "lon": 0.73
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "K5NOT-11",
   "flight_id": "K5NOT-11_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 16:55:37",
   "seed_lat": 45.12494,
   "seed_lon": -79.79166,
   "seed_alt_m": 13240.0,
   "seed_age_h": 0.41,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 17:00:00",
    "lat": 23.49826,
    "lon": -76.98559,
    "alt_m": 13426.4
   },
   "member_spread_deg": {
    "lat": 21.19,
    "lon": 207.11
   },
   "member_spread_now_deg": {
    "lat": 0.35,
    "lon": 0.21
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KC3LBR-449",
   "flight_id": "KC3LBR-449_2026-07-06",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 14:57:04",
   "seed_lat": 59.41667,
   "seed_lon": 73.5,
   "seed_alt_m": 13410.0,
   "seed_age_h": 2.38,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 14:30:00",
    "lat": 67.77192,
    "lon": 54.5793,
    "alt_m": 13209.0
   },
   "member_spread_deg": {
    "lat": 15.19,
    "lon": 114.91
   },
   "member_spread_now_deg": {
    "lat": 0.11,
    "lon": 0.33
   },
   "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": 77.66,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 11:45:00",
    "lat": 56.92704,
    "lon": 149.31262,
    "alt_m": 12434.1
   },
   "member_spread_deg": {
    "lat": 13.65,
    "lon": 315.27
   },
   "member_spread_now_deg": {
    "lat": 30.01,
    "lon": 102.31
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "KD7FXO-1",
   "flight_id": "KD7FXO-1_2026-08-02",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 15:50:00",
   "seed_lat": 36.875,
   "seed_lon": 24.08333,
   "seed_alt_m": 12710.0,
   "seed_age_h": 1.5,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 15:15:00",
    "lat": 31.33115,
    "lon": 172.98346,
    "alt_m": 13119.0
   },
   "member_spread_deg": {
    "lat": 27.03,
    "lon": 357.26
   },
   "member_spread_now_deg": {
    "lat": 0.45,
    "lon": 0.41
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KE8RES-8",
   "flight_id": "KE8RES-8_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 16:51:00",
   "seed_lat": 62.0625,
   "seed_lon": -44.20833,
   "seed_alt_m": 12260.0,
   "seed_age_h": 0.48,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-22 16:15:00",
    "lat": 86.68239,
    "lon": -102.11145,
    "alt_m": 12196.0
   },
   "member_spread_deg": {
    "lat": 34.97,
    "lon": 262.37
   },
   "member_spread_now_deg": {
    "lat": 0.12,
    "lon": 0.09
   },
   "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": 44.15,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-22 11:45:00",
    "lat": 32.21961,
    "lon": -28.53368,
    "alt_m": 11253.9
   },
   "member_spread_deg": {
    "lat": 23.84,
    "lon": 85.84
   },
   "member_spread_now_deg": {
    "lat": 15.84,
    "lon": 357.63
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "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": 330.41,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-22 11:30:00",
    "lat": -18.84239,
    "lon": -67.60485,
    "alt_m": 12363.7
   },
   "member_spread_deg": {
    "lat": 48.16,
    "lon": 235.15
   },
   "member_spread_now_deg": {
    "lat": 31.3,
    "lon": 80.03
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "KI6DS-11",
   "flight_id": "KI6DS-11_2026-02-03",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 10:30:45",
   "seed_lat": 75.41661,
   "seed_lon": 111.33335,
   "seed_alt_m": 13180.0,
   "seed_age_h": 6.82,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 11:30:00",
    "lat": 43.58098,
    "lon": -145.52624,
    "alt_m": 13524.4
   },
   "member_spread_deg": {
    "lat": 38.32,
    "lon": 346.72
   },
   "member_spread_now_deg": {
    "lat": 3.09,
    "lon": 0.95
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "SP2ROC-41",
   "flight_id": "SP2ROC-41_2026-01-25",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 05:33:00",
   "seed_lat": 15.875,
   "seed_lon": 162.83333,
   "seed_alt_m": 16530.0,
   "seed_age_h": 11.78,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 11:30:00",
    "lat": 10.67231,
    "lon": 32.06224,
    "alt_m": 16434.0
   },
   "member_spread_deg": {
    "lat": 36.98,
    "lon": 82.33
   },
   "member_spread_now_deg": {
    "lat": 2.94,
    "lon": 1.5
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "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": 277.24,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 11:30:00",
    "lat": 27.46361,
    "lon": 178.19464,
    "alt_m": 13192.6
   },
   "member_spread_deg": {
    "lat": 46.76,
    "lon": 353.14
   },
   "member_spread_now_deg": {
    "lat": 30.17,
    "lon": 246.26
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "VE3VRO-36",
   "flight_id": "VE3VRO-36_2026-07-30",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 06:46:00",
   "seed_lat": 49.89583,
   "seed_lon": 152.20833,
   "seed_alt_m": 13420.0,
   "seed_age_h": 10.57,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 11:45:00",
    "lat": 47.29499,
    "lon": -61.62629,
    "alt_m": 13114.4
   },
   "member_spread_deg": {
    "lat": 28.45,
    "lon": 114.2
   },
   "member_spread_now_deg": {
    "lat": 0.53,
    "lon": 5.73
   },
   "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": 39.24,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 11:30:00",
    "lat": 67.82833,
    "lon": -79.4424,
    "alt_m": 13054.8
   },
   "member_spread_deg": {
    "lat": 24.98,
    "lon": 59.31
   },
   "member_spread_now_deg": {
    "lat": 19.31,
    "lon": 355.75
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "ZS6SRC-37",
   "flight_id": "ZS6SRC-37_2026-07-31",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 04:39:00",
   "seed_lat": -24.20833,
   "seed_lon": 158.0,
   "seed_alt_m": 12420.0,
   "seed_age_h": 12.68,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-22 11:45:00",
    "lat": -12.15191,
    "lon": 16.92619,
    "alt_m": 12682.8
   },
   "member_spread_deg": {
    "lat": 30.06,
    "lon": 117.16
   },
   "member_spread_now_deg": {
    "lat": 3.67,
    "lon": 357.37
   },
   "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": 82.98,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-22 11:45:00",
    "lat": -20.41269,
    "lon": 0.71827,
    "alt_m": 15748.9
   },
   "member_spread_deg": {
    "lat": 22.2,
    "lon": 195.38
   },
   "member_spread_now_deg": {
    "lat": 7.47,
    "lon": 343.24
   },
   "display_as": "region",
   "display_reason": "member_spread"
  }
 ]
}