{
 "generated_utc": "2026-08-15T11:27:17Z",
 "gfs_cycle_utc": "2026-08-15T06:00:00Z",
 "model": {
  "source": "NCEP GFS 0.50 degree",
  "vertical_coordinate": "constant density (isopycnic)",
  "horizon_hours": 486.5,
  "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_06Z.csv.gz",
  "trajectories_geojson_gz": "PBA_forecast_20260815_06Z.geojson.gz"
 },
 "counts": {
  "flights": 24,
  "members": 9,
  "rows": 94446
 },
 "flights": [
  {
   "callsign": "AG6NS-23",
   "flight_id": "AG6NS-23_2026-02-07",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 10:53:40",
   "seed_lat": -58.0625,
   "seed_lon": 13.62501,
   "seed_alt_m": 12540.0,
   "seed_age_h": 0.44,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 11:00:00",
    "lat": -51.10762,
    "lon": 12.11807,
    "alt_m": 12450.5
   },
   "member_spread_deg": {
    "lat": 19.37,
    "lon": 74.92
   },
   "member_spread_now_deg": {
    "lat": 0.11,
    "lon": 0.71
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS53",
   "flight_id": "BSS53_2026-03-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 09:22:18",
   "seed_lat": 54.25,
   "seed_lon": 73.125,
   "seed_alt_m": 12810.0,
   "seed_age_h": 1.96,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 08:45:00",
    "lat": 45.70295,
    "lon": -147.43353,
    "alt_m": 12721.6
   },
   "member_spread_deg": {
    "lat": 15.13,
    "lon": 13.82
   },
   "member_spread_now_deg": {
    "lat": 0.27,
    "lon": 0.86
   },
   "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": 11.0,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 05:45:00",
    "lat": 56.69929,
    "lon": -114.13614,
    "alt_m": 13859.9
   },
   "member_spread_deg": {
    "lat": 16.87,
    "lon": 101.44
   },
   "member_spread_now_deg": {
    "lat": 1.94,
    "lon": 3.67
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-23",
   "flight_id": "DG2GG-23_2026-05-23",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 10:49:00",
   "seed_lat": 44.4375,
   "seed_lon": 21.625,
   "seed_alt_m": 12810.0,
   "seed_age_h": 0.52,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 10:15:00",
    "lat": 41.2389,
    "lon": -147.90358,
    "alt_m": 12858.2
   },
   "member_spread_deg": {
    "lat": 30.03,
    "lon": 26.44
   },
   "member_spread_now_deg": {
    "lat": 0.11,
    "lon": 0.15
   },
   "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": 131.03,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-22 05:45:00",
    "lat": 1.40904,
    "lon": -85.70816,
    "alt_m": 14033.2
   },
   "member_spread_deg": {
    "lat": 47.89,
    "lon": 156.35
   },
   "member_spread_now_deg": {
    "lat": 32.75,
    "lon": 62.62
   },
   "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": 270.38,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 05:30:00",
    "lat": 40.92022,
    "lon": 55.96479,
    "alt_m": 13384.0
   },
   "member_spread_deg": {
    "lat": 87.87,
    "lon": 285.84
   },
   "member_spread_now_deg": {
    "lat": 71.82,
    "lon": 220.01
   },
   "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 02:06:00",
   "seed_lat": 35.66667,
   "seed_lon": -137.58333,
   "seed_alt_m": 13020.0,
   "seed_age_h": 9.23,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 05:30:00",
    "lat": 52.90962,
    "lon": 68.83167,
    "alt_m": 12481.5
   },
   "member_spread_deg": {
    "lat": 7.77,
    "lon": 99.48
   },
   "member_spread_now_deg": {
    "lat": 1.33,
    "lon": 4.41
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-31",
   "flight_id": "DG2GG-31_2026-08-13",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 09:17:00",
   "seed_lat": 42.45833,
   "seed_lon": 14.125,
   "seed_alt_m": 13310.0,
   "seed_age_h": 2.05,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 08:45:00",
    "lat": 66.69885,
    "lon": -156.26118,
    "alt_m": 12836.9
   },
   "member_spread_deg": {
    "lat": 33.75,
    "lon": 344.83
   },
   "member_spread_now_deg": {
    "lat": 0.21,
    "lon": 0.23
   },
   "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": 0.62,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-22 10:15:00",
    "lat": 74.17988,
    "lon": 175.17397,
    "alt_m": 11557.2
   },
   "member_spread_deg": {
    "lat": 22.34,
    "lon": 350.16
   },
   "member_spread_now_deg": {
    "lat": 0.28,
    "lon": 1.04
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "EI6BFW-18",
   "flight_id": "EI6BFW-18_2026-07-25",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 00:23:00",
   "seed_lat": 63.79167,
   "seed_lon": -116.41667,
   "seed_alt_m": 12610.0,
   "seed_age_h": 10.95,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 05:30:00",
    "lat": 59.82177,
    "lon": 39.64232,
    "alt_m": 12426.0
   },
   "member_spread_deg": {
    "lat": 22.25,
    "lon": 183.75
   },
   "member_spread_now_deg": {
    "lat": 0.85,
    "lon": 6.83
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "K5NOT-11",
   "flight_id": "K5NOT-11_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-14 23:10:37",
   "seed_lat": 39.08328,
   "seed_lon": -111.83333,
   "seed_alt_m": 13090.0,
   "seed_age_h": 12.16,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 05:45:00",
    "lat": 50.97934,
    "lon": 122.15403,
    "alt_m": 12844.4
   },
   "member_spread_deg": {
    "lat": 35.21,
    "lon": 207.99
   },
   "member_spread_now_deg": {
    "lat": 5.33,
    "lon": 13.14
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KC3LBR-449",
   "flight_id": "KC3LBR-449_2026-07-06",
   "payload_type": "WSPR",
   "seed_time": "2026-08-14 15:22:33",
   "seed_lat": 50.70833,
   "seed_lon": 58.5,
   "seed_alt_m": 13420.0,
   "seed_age_h": 19.96,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 05:30:00",
    "lat": 76.80746,
    "lon": -176.33767,
    "alt_m": 12893.5
   },
   "member_spread_deg": {
    "lat": 38.64,
    "lon": 312.1
   },
   "member_spread_now_deg": {
    "lat": 9.13,
    "lon": 14.22
   },
   "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": 71.66,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 05:45:00",
    "lat": 53.40618,
    "lon": 139.34827,
    "alt_m": 12523.6
   },
   "member_spread_deg": {
    "lat": 17.68,
    "lon": 294.16
   },
   "member_spread_now_deg": {
    "lat": 30.4,
    "lon": 89.93
   },
   "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 10:25:00",
   "seed_lat": 36.41667,
   "seed_lon": 19.75,
   "seed_alt_m": 12750.0,
   "seed_age_h": 0.92,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 10:00:00",
    "lat": 38.2835,
    "lon": -175.95968,
    "alt_m": 13012.4
   },
   "member_spread_deg": {
    "lat": 29.13,
    "lon": 359.02
   },
   "member_spread_now_deg": {
    "lat": 0.3,
    "lon": 0.34
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KE8RES-8",
   "flight_id": "KE8RES-8_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-15 10:31:00",
   "seed_lat": 59.89583,
   "seed_lon": -46.45833,
   "seed_alt_m": 12260.0,
   "seed_age_h": 0.82,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-22 10:00:00",
    "lat": 69.52758,
    "lon": 142.92264,
    "alt_m": 12079.1
   },
   "member_spread_deg": {
    "lat": 39.49,
    "lon": 176.31
   },
   "member_spread_now_deg": {
    "lat": 0.24,
    "lon": 0.3
   },
   "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": 38.15,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-22 05:45:00",
    "lat": 29.75998,
    "lon": -42.22894,
    "alt_m": 11210.6
   },
   "member_spread_deg": {
    "lat": 20.02,
    "lon": 117.96
   },
   "member_spread_now_deg": {
    "lat": 7.91,
    "lon": 359.95
   },
   "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": 324.41,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-22 05:30:00",
    "lat": -8.77952,
    "lon": -56.24649,
    "alt_m": 12368.4
   },
   "member_spread_deg": {
    "lat": 44.7,
    "lon": 127.91
   },
   "member_spread_now_deg": {
    "lat": 29.39,
    "lon": 73.82
   },
   "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": 0.82,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 10:00:00",
    "lat": 41.2634,
    "lon": -156.89132,
    "alt_m": 13541.1
   },
   "member_spread_deg": {
    "lat": 42.16,
    "lon": 357.46
   },
   "member_spread_now_deg": {
    "lat": 0.29,
    "lon": 0.27
   },
   "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": 5.78,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 05:30:00",
    "lat": 12.26934,
    "lon": 34.30103,
    "alt_m": 16366.5
   },
   "member_spread_deg": {
    "lat": 37.81,
    "lon": 92.38
   },
   "member_spread_now_deg": {
    "lat": 1.93,
    "lon": 0.46
   },
   "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": 271.24,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 05:30:00",
    "lat": 36.91536,
    "lon": -173.60635,
    "alt_m": 13172.9
   },
   "member_spread_deg": {
    "lat": 40.07,
    "lon": 302.74
   },
   "member_spread_now_deg": {
    "lat": 30.89,
    "lon": 242.57
   },
   "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": 4.57,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 06:15:00",
    "lat": 46.73957,
    "lon": -58.87815,
    "alt_m": 13084.1
   },
   "member_spread_deg": {
    "lat": 29.72,
    "lon": 131.58
   },
   "member_spread_now_deg": {
    "lat": 0.3,
    "lon": 2.86
   },
   "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": 33.24,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-22 05:30:00",
    "lat": 50.88876,
    "lon": -63.08739,
    "alt_m": 13128.4
   },
   "member_spread_deg": {
    "lat": 38.16,
    "lon": 66.79
   },
   "member_spread_now_deg": {
    "lat": 11.47,
    "lon": 354.88
   },
   "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": 6.68,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-22 05:45:00",
    "lat": -28.0221,
    "lon": 50.80944,
    "alt_m": 12561.8
   },
   "member_spread_deg": {
    "lat": 19.33,
    "lon": 131.47
   },
   "member_spread_now_deg": {
    "lat": 1.91,
    "lon": 5.95
   },
   "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": 76.98,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-22 05:45:00",
    "lat": -30.91997,
    "lon": 24.52338,
    "alt_m": 15529.0
   },
   "member_spread_deg": {
    "lat": 24.94,
    "lon": 208.77
   },
   "member_spread_now_deg": {
    "lat": 6.9,
    "lon": 345.2
   },
   "display_as": "region",
   "display_reason": "member_spread"
  }
 ]
}