{
 "generated_utc": "2026-08-16T11:26:48Z",
 "gfs_cycle_utc": "2026-08-16T06:00:00Z",
 "model": {
  "source": "NCEP GFS 0.50 degree",
  "vertical_coordinate": "constant density (isopycnic)",
  "horizon_hours": 457.5,
  "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_20260816_06Z.csv.gz",
  "trajectories_geojson_gz": "PBA_forecast_20260816_06Z.geojson.gz"
 },
 "counts": {
  "flights": 24,
  "members": 9,
  "rows": 91359
 },
 "flights": [
  {
   "callsign": "AG6NS-23",
   "flight_id": "AG6NS-23_2026-02-07",
   "payload_type": "WSPR",
   "seed_time": "2026-08-16 10:53:40",
   "seed_lat": -56.64583,
   "seed_lon": 62.45835,
   "seed_alt_m": 12330.0,
   "seed_age_h": 0.44,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-23 11:00:00",
    "lat": -59.21078,
    "lon": 74.20978,
    "alt_m": 12870.1
   },
   "member_spread_deg": {
    "lat": 18.68,
    "lon": 124.85
   },
   "member_spread_now_deg": {
    "lat": 0.23,
    "lon": 0.19
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS53",
   "flight_id": "BSS53_2026-03-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-16 09:13:48",
   "seed_lat": 53.125,
   "seed_lon": 92.70833,
   "seed_alt_m": 12740.0,
   "seed_age_h": 2.1,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 08:45:00",
    "lat": 65.10724,
    "lon": -92.6729,
    "alt_m": 12437.2
   },
   "member_spread_deg": {
    "lat": 45.28,
    "lon": 167.15
   },
   "member_spread_now_deg": {
    "lat": 0.21,
    "lon": 1.29
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS54",
   "flight_id": "BSS54_2026-07-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 23:28:18",
   "seed_lat": 48.02083,
   "seed_lon": 165.79167,
   "seed_alt_m": 14140.0,
   "seed_age_h": 11.86,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-23 05:30:00",
    "lat": 44.55734,
    "lon": -72.92629,
    "alt_m": 14162.1
   },
   "member_spread_deg": {
    "lat": 27.37,
    "lon": 102.17
   },
   "member_spread_now_deg": {
    "lat": 0.91,
    "lon": 2.79
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-23",
   "flight_id": "DG2GG-23_2026-05-23",
   "payload_type": "WSPR",
   "seed_time": "2026-08-16 10:09:00",
   "seed_lat": 43.29167,
   "seed_lon": 30.625,
   "seed_alt_m": 12660.0,
   "seed_age_h": 1.18,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 09:45:00",
    "lat": 36.93953,
    "lon": -139.18052,
    "alt_m": 13029.9
   },
   "member_spread_deg": {
    "lat": 39.04,
    "lon": 56.58
   },
   "member_spread_now_deg": {
    "lat": 0.16,
    "lon": 0.41
   },
   "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": 155.03,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-23 05:45:00",
    "lat": 10.01486,
    "lon": -86.23678,
    "alt_m": 14085.4
   },
   "member_spread_deg": {
    "lat": 34.34,
    "lon": 139.89
   },
   "member_spread_now_deg": {
    "lat": 34.06,
    "lon": 78.14
   },
   "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": 294.38,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 05:30:00",
    "lat": 40.7792,
    "lon": 74.45361,
    "alt_m": 13283.6
   },
   "member_spread_deg": {
    "lat": 89.5,
    "lon": 310.22
   },
   "member_spread_now_deg": {
    "lat": 71.56,
    "lon": 207.73
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "DG2GG-30",
   "flight_id": "DG2GG-30_2026-08-07",
   "payload_type": "WSPR",
   "seed_time": "2026-08-16 01:11:00",
   "seed_lat": 41.16667,
   "seed_lon": -123.08333,
   "seed_alt_m": 13380.0,
   "seed_age_h": 10.15,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 05:45:00",
    "lat": 49.27621,
    "lon": 92.14911,
    "alt_m": 13125.6
   },
   "member_spread_deg": {
    "lat": 27.79,
    "lon": 79.73
   },
   "member_spread_now_deg": {
    "lat": 2.13,
    "lon": 1.98
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-31",
   "flight_id": "DG2GG-31_2026-08-13",
   "payload_type": "WSPR",
   "seed_time": "2026-08-16 10:22:00",
   "seed_lat": 40.3125,
   "seed_lon": 25.20833,
   "seed_alt_m": 13200.0,
   "seed_age_h": 0.97,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 09:45:00",
    "lat": 40.61683,
    "lon": -169.40221,
    "alt_m": 13441.1
   },
   "member_spread_deg": {
    "lat": 30.93,
    "lon": 33.26
   },
   "member_spread_now_deg": {
    "lat": 0.2,
    "lon": 0.24
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DN3LEO-13",
   "flight_id": "DN3LEO-13_2026-04-12",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 23:03:00",
   "seed_lat": 85.5,
   "seed_lon": 140.70833,
   "seed_alt_m": 11810.0,
   "seed_age_h": 12.28,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-23 05:30:00",
    "lat": 61.49872,
    "lon": 124.55272,
    "alt_m": 11953.9
   },
   "member_spread_deg": {
    "lat": 19.07,
    "lon": 353.49
   },
   "member_spread_now_deg": {
    "lat": 2.08,
    "lon": 111.1
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "EI6BFW-18",
   "flight_id": "EI6BFW-18_2026-07-25",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 23:18:00",
   "seed_lat": 61.66667,
   "seed_lon": -98.625,
   "seed_alt_m": 12590.0,
   "seed_age_h": 12.03,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 05:45:00",
    "lat": 60.14544,
    "lon": 29.04469,
    "alt_m": 12401.6
   },
   "member_spread_deg": {
    "lat": 22.16,
    "lon": 105.39
   },
   "member_spread_now_deg": {
    "lat": 1.95,
    "lon": 1.75
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "GSN-TS",
   "flight_id": "GSN-TS_2026-08-15",
   "payload_type": "OTHER",
   "seed_time": "2026-08-16 01:30:23",
   "seed_lat": 53.81866,
   "seed_lon": 16.61656,
   "seed_alt_m": 9972.0,
   "seed_age_h": 9.83,
   "float_reliable": false,
   "dead_reckoned": false,
   "levels_spanned": 4,
   "nominal_end": {
    "valid_time": "2026-08-23 05:30:00",
    "lat": 71.14563,
    "lon": -133.74562,
    "alt_m": 9847.3
   },
   "member_spread_deg": {
    "lat": 32.48,
    "lon": 321.55
   },
   "member_spread_now_deg": {
    "lat": 1.98,
    "lon": 4.31
   },
   "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": 14.49,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 05:45:00",
    "lat": 33.22205,
    "lon": -68.81372,
    "alt_m": 13412.4
   },
   "member_spread_deg": {
    "lat": 21.05,
    "lon": 98.84
   },
   "member_spread_now_deg": {
    "lat": 1.37,
    "lon": 6.03
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KC3LBR-449",
   "flight_id": "KC3LBR-449_2026-07-06",
   "payload_type": "WSPR",
   "seed_time": "2026-08-16 10:57:03",
   "seed_lat": 62.08333,
   "seed_lon": 72.08333,
   "seed_alt_m": 13370.0,
   "seed_age_h": 0.38,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 11:00:00",
    "lat": 64.73271,
    "lon": 121.88661,
    "alt_m": 13150.7
   },
   "member_spread_deg": {
    "lat": 12.89,
    "lon": 296.44
   },
   "member_spread_now_deg": {
    "lat": 0.02,
    "lon": 0.09
   },
   "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": 95.66,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 05:45:00",
    "lat": 63.67078,
    "lon": 175.19895,
    "alt_m": 12469.6
   },
   "member_spread_deg": {
    "lat": 22.84,
    "lon": 263.11
   },
   "member_spread_now_deg": {
    "lat": 27.36,
    "lon": 271.54
   },
   "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": 19.5,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 05:45:00",
    "lat": 25.85602,
    "lon": -179.867,
    "alt_m": 13076.7
   },
   "member_spread_deg": {
    "lat": 42.12,
    "lon": 349.88
   },
   "member_spread_now_deg": {
    "lat": 2.68,
    "lon": 9.57
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KE8RES-8",
   "flight_id": "KE8RES-8_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 20:26:00",
   "seed_lat": 63.3125,
   "seed_lon": -42.875,
   "seed_alt_m": 12260.0,
   "seed_age_h": 14.9,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-23 05:30:00",
    "lat": 73.77788,
    "lon": 159.87364,
    "alt_m": 12002.3
   },
   "member_spread_deg": {
    "lat": 30.82,
    "lon": 281.4
   },
   "member_spread_now_deg": {
    "lat": 1.53,
    "lon": 7.19
   },
   "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": 62.15,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-23 05:45:00",
    "lat": 29.60512,
    "lon": -42.80951,
    "alt_m": 11243.6
   },
   "member_spread_deg": {
    "lat": 34.58,
    "lon": 211.17
   },
   "member_spread_now_deg": {
    "lat": 14.22,
    "lon": 22.08
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KI6DS-11",
   "flight_id": "KI6DS-11_2026-02-03",
   "payload_type": "WSPR",
   "seed_time": "2026-08-16 09:35:45",
   "seed_lat": 70.24995,
   "seed_lon": 114.29169,
   "seed_alt_m": 13120.0,
   "seed_age_h": 1.74,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 09:00:00",
    "lat": 66.67871,
    "lon": -103.36459,
    "alt_m": 13168.7
   },
   "member_spread_deg": {
    "lat": 28.34,
    "lon": 160.0
   },
   "member_spread_now_deg": {
    "lat": 0.7,
    "lon": 0.21
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "SP2ROC-41",
   "flight_id": "SP2ROC-41_2026-01-25",
   "payload_type": "WSPR",
   "seed_time": "2026-08-16 06:36:00",
   "seed_lat": 15.47917,
   "seed_lon": 145.875,
   "seed_alt_m": 16600.0,
   "seed_age_h": 4.73,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 06:00:00",
    "lat": 8.7754,
    "lon": 21.17099,
    "alt_m": 16406.2
   },
   "member_spread_deg": {
    "lat": 39.6,
    "lon": 107.87
   },
   "member_spread_now_deg": {
    "lat": 0.62,
    "lon": 1.48
   },
   "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": 295.24,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 05:30:00",
    "lat": 40.99577,
    "lon": -131.16859,
    "alt_m": 13099.8
   },
   "member_spread_deg": {
    "lat": 44.29,
    "lon": 323.72
   },
   "member_spread_now_deg": {
    "lat": 31.93,
    "lon": 253.66
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "VE3VRO-36",
   "flight_id": "VE3VRO-36_2026-07-30",
   "payload_type": "WSPR",
   "seed_time": "2026-08-16 06:11:00",
   "seed_lat": 45.33333,
   "seed_lon": 165.0,
   "seed_alt_m": 13400.0,
   "seed_age_h": 5.15,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 05:45:00",
    "lat": 63.35267,
    "lon": -20.95952,
    "alt_m": 13083.3
   },
   "member_spread_deg": {
    "lat": 33.58,
    "lon": 123.15
   },
   "member_spread_now_deg": {
    "lat": 0.47,
    "lon": 1.96
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "W0RBO-12",
   "flight_id": "W0RBO-12_2026-05-02",
   "payload_type": "WSPR",
   "seed_time": "2026-08-16 04:20:23",
   "seed_lat": 50.79161,
   "seed_lon": 177.66669,
   "seed_alt_m": 13240.0,
   "seed_age_h": 6.99,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 05:45:00",
    "lat": 54.61649,
    "lon": -46.56146,
    "alt_m": 13273.9
   },
   "member_spread_deg": {
    "lat": 45.28,
    "lon": 67.33
   },
   "member_spread_now_deg": {
    "lat": 1.49,
    "lon": 4.24
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "ZS6SRC-37",
   "flight_id": "ZS6SRC-37_2026-07-31",
   "payload_type": "WSPR",
   "seed_time": "2026-08-16 01:39:00",
   "seed_lat": -27.66667,
   "seed_lon": -155.41667,
   "seed_alt_m": 12330.0,
   "seed_age_h": 9.68,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-23 05:45:00",
    "lat": -32.46894,
    "lon": 94.31075,
    "alt_m": 12077.1
   },
   "member_spread_deg": {
    "lat": 13.06,
    "lon": 91.1
   },
   "member_spread_now_deg": {
    "lat": 1.54,
    "lon": 4.16
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "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": 100.98,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-23 05:45:00",
    "lat": -9.32617,
    "lon": -8.23807,
    "alt_m": 15952.0
   },
   "member_spread_deg": {
    "lat": 28.74,
    "lon": 267.65
   },
   "member_spread_now_deg": {
    "lat": 12.32,
    "lon": 335.43
   },
   "display_as": "region",
   "display_reason": "member_spread"
  }
 ]
}