{
 "generated_utc": "2026-08-17T05:27:09Z",
 "gfs_cycle_utc": "2026-08-17T00:00:00Z",
 "model": {
  "source": "NCEP GFS 0.50 degree",
  "vertical_coordinate": "constant density (isopycnic)",
  "horizon_hours": 475.5,
  "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_20260817_00Z.csv.gz",
  "trajectories_geojson_gz": "PBA_forecast_20260817_00Z.geojson.gz"
 },
 "counts": {
  "flights": 22,
  "members": 9,
  "rows": 87390
 },
 "flights": [
  {
   "callsign": "AG6NS-23",
   "flight_id": "AG6NS-23_2026-02-07",
   "payload_type": "WSPR",
   "seed_time": "2026-08-17 04:53:40",
   "seed_lat": -51.9375,
   "seed_lon": 97.62501,
   "seed_alt_m": 12240.0,
   "seed_age_h": 0.44,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-24 05:00:00",
    "lat": -64.78155,
    "lon": 101.77925,
    "alt_m": 12518.1
   },
   "member_spread_deg": {
    "lat": 7.08,
    "lon": 36.28
   },
   "member_spread_now_deg": {
    "lat": 0.17,
    "lon": 0.21
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS53",
   "flight_id": "BSS53_2026-03-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-16 23:50:18",
   "seed_lat": 51.79167,
   "seed_lon": 106.20833,
   "seed_alt_m": 12680.0,
   "seed_age_h": 5.5,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 23:45:00",
    "lat": 75.03068,
    "lon": 91.19143,
    "alt_m": 12335.0
   },
   "member_spread_deg": {
    "lat": 50.23,
    "lon": 249.06
   },
   "member_spread_now_deg": {
    "lat": 0.81,
    "lon": 5.4
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "BSS54",
   "flight_id": "BSS54_2026-07-09",
   "payload_type": "WSPR",
   "seed_time": "2026-08-17 01:17:18",
   "seed_lat": 41.95833,
   "seed_lon": 177.125,
   "seed_alt_m": 14090.0,
   "seed_age_h": 4.05,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-24 00:45:00",
    "lat": 44.68505,
    "lon": -72.23243,
    "alt_m": 13860.0
   },
   "member_spread_deg": {
    "lat": 25.26,
    "lon": 90.61
   },
   "member_spread_now_deg": {
    "lat": 0.3,
    "lon": 0.85
   },
   "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": 19.18,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 23:45:00",
    "lat": 40.45653,
    "lon": -135.64087,
    "alt_m": 12993.5
   },
   "member_spread_deg": {
    "lat": 40.24,
    "lon": 310.05
   },
   "member_spread_now_deg": {
    "lat": 3.44,
    "lon": 15.53
   },
   "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": 173.03,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-23 23:45:00",
    "lat": 3.84133,
    "lon": -71.44219,
    "alt_m": 14096.8
   },
   "member_spread_deg": {
    "lat": 62.26,
    "lon": 149.2
   },
   "member_spread_now_deg": {
    "lat": 32.83,
    "lon": 83.72
   },
   "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": 312.38,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 23:30:00",
    "lat": 44.97968,
    "lon": 110.61863,
    "alt_m": 13350.8
   },
   "member_spread_deg": {
    "lat": 90.9,
    "lon": 305.96
   },
   "member_spread_now_deg": {
    "lat": 69.01,
    "lon": 208.69
   },
   "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 23:31:00",
   "seed_lat": 49.47917,
   "seed_lon": -107.5,
   "seed_alt_m": 12730.0,
   "seed_age_h": 5.82,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 23:30:00",
    "lat": 54.00778,
    "lon": 107.96799,
    "alt_m": 12480.0
   },
   "member_spread_deg": {
    "lat": 27.96,
    "lon": 72.47
   },
   "member_spread_now_deg": {
    "lat": 0.72,
    "lon": 1.99
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DG2GG-31",
   "flight_id": "DG2GG-31_2026-08-13",
   "payload_type": "WSPR",
   "seed_time": "2026-08-16 12:32:00",
   "seed_lat": 40.41667,
   "seed_lon": 26.29167,
   "seed_alt_m": 13180.0,
   "seed_age_h": 16.8,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 23:30:00",
    "lat": 42.59494,
    "lon": -148.2239,
    "alt_m": 13274.8
   },
   "member_spread_deg": {
    "lat": 37.0,
    "lon": 33.56
   },
   "member_spread_now_deg": {
    "lat": 2.75,
    "lon": 4.44
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "DN3LEO-13",
   "flight_id": "DN3LEO-13_2026-04-12",
   "payload_type": "WSPR",
   "seed_time": "2026-08-16 22:18:00",
   "seed_lat": 87.5,
   "seed_lon": -76.08333,
   "seed_alt_m": 11730.0,
   "seed_age_h": 7.03,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-23 23:45:00",
    "lat": 70.53373,
    "lon": 173.82147,
    "alt_m": 11910.2
   },
   "member_spread_deg": {
    "lat": 19.3,
    "lon": 354.72
   },
   "member_spread_now_deg": {
    "lat": 0.32,
    "lon": 29.78
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "EI6BFW-18",
   "flight_id": "EI6BFW-18_2026-07-25",
   "payload_type": "WSPR",
   "seed_time": "2026-08-16 22:08:00",
   "seed_lat": 59.16667,
   "seed_lon": -78.625,
   "seed_alt_m": 12500.0,
   "seed_age_h": 7.2,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 23:45:00",
    "lat": 50.83391,
    "lon": 71.47068,
    "alt_m": 12741.3
   },
   "member_spread_deg": {
    "lat": 28.69,
    "lon": 83.21
   },
   "member_spread_now_deg": {
    "lat": 0.15,
    "lon": 1.98
   },
   "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": 32.49,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 23:45:00",
    "lat": 38.11804,
    "lon": -112.09713,
    "alt_m": 13364.8
   },
   "member_spread_deg": {
    "lat": 19.89,
    "lon": 98.44
   },
   "member_spread_now_deg": {
    "lat": 4.8,
    "lon": 17.85
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KC3LBR-449",
   "flight_id": "KC3LBR-449_2026-07-06",
   "payload_type": "WSPR",
   "seed_time": "2026-08-17 00:47:18",
   "seed_lat": 65.0,
   "seed_lon": 62.95833,
   "seed_alt_m": 13240.0,
   "seed_age_h": 4.55,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-24 00:15:00",
    "lat": 60.66052,
    "lon": 147.48396,
    "alt_m": 13075.5
   },
   "member_spread_deg": {
    "lat": 9.91,
    "lon": 34.92
   },
   "member_spread_now_deg": {
    "lat": 0.39,
    "lon": 2.36
   },
   "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": 113.66,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 23:45:00",
    "lat": 66.0991,
    "lon": -177.29856,
    "alt_m": 12526.8
   },
   "member_spread_deg": {
    "lat": 34.73,
    "lon": 310.55
   },
   "member_spread_now_deg": {
    "lat": 23.93,
    "lon": 246.4
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "KD7FXO-1",
   "flight_id": "KD7FXO-1_2026-08-02",
   "payload_type": "WSPR",
   "seed_time": "2026-08-17 03:55:00",
   "seed_lat": 47.0625,
   "seed_lon": 89.54167,
   "seed_alt_m": 12490.0,
   "seed_age_h": 1.42,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-24 03:30:00",
    "lat": 27.26747,
    "lon": -130.13661,
    "alt_m": 12934.5
   },
   "member_spread_deg": {
    "lat": 28.27,
    "lon": 356.63
   },
   "member_spread_now_deg": {
    "lat": 0.38,
    "lon": 0.91
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "KE8RES-8",
   "flight_id": "KE8RES-8_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-08-16 19:31:00",
   "seed_lat": 70.25,
   "seed_lon": -41.83333,
   "seed_alt_m": 12260.0,
   "seed_age_h": 9.82,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-23 23:30:00",
    "lat": 80.6642,
    "lon": 175.26396,
    "alt_m": 11801.7
   },
   "member_spread_deg": {
    "lat": 16.74,
    "lon": 354.65
   },
   "member_spread_now_deg": {
    "lat": 1.81,
    "lon": 3.67
   },
   "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": 80.15,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-23 23:45:00",
    "lat": 43.89964,
    "lon": 16.42654,
    "alt_m": 11191.8
   },
   "member_spread_deg": {
    "lat": 33.06,
    "lon": 173.6
   },
   "member_spread_now_deg": {
    "lat": 35.65,
    "lon": 21.35
   },
   "display_as": "region",
   "display_reason": "seed_age"
  },
  {
   "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": 19.74,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 23:30:00",
    "lat": 87.53494,
    "lon": -91.80786,
    "alt_m": 12761.3
   },
   "member_spread_deg": {
    "lat": 26.25,
    "lon": 274.54
   },
   "member_spread_now_deg": {
    "lat": 8.51,
    "lon": 2.24
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "SP2ROC-41",
   "flight_id": "SP2ROC-41_2026-01-25",
   "payload_type": "WSPR",
   "seed_time": "2026-08-17 04:46:00",
   "seed_lat": 13.27083,
   "seed_lon": 135.04167,
   "seed_alt_m": 16700.0,
   "seed_age_h": 0.57,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-24 04:15:00",
    "lat": 13.74389,
    "lon": 8.70939,
    "alt_m": 16531.6
   },
   "member_spread_deg": {
    "lat": 43.51,
    "lon": 126.33
   },
   "member_spread_now_deg": {
    "lat": 0.24,
    "lon": 0.31
   },
   "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": 313.24,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-23 23:30:00",
    "lat": 34.20006,
    "lon": -127.40403,
    "alt_m": 13150.9
   },
   "member_spread_deg": {
    "lat": 48.43,
    "lon": 312.42
   },
   "member_spread_now_deg": {
    "lat": 30.94,
    "lon": 260.03
   },
   "display_as": "region",
   "display_reason": "member_spread"
  },
  {
   "callsign": "VE3VRO-36",
   "flight_id": "VE3VRO-36_2026-07-30",
   "payload_type": "WSPR",
   "seed_time": "2026-08-17 04:41:00",
   "seed_lat": 38.02083,
   "seed_lon": 176.70833,
   "seed_alt_m": 13420.0,
   "seed_age_h": 0.65,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-24 04:15:00",
    "lat": 52.98536,
    "lon": -50.3325,
    "alt_m": 13090.3
   },
   "member_spread_deg": {
    "lat": 27.31,
    "lon": 96.96
   },
   "member_spread_now_deg": {
    "lat": 0.02,
    "lon": 0.19
   },
   "display_as": "track",
   "display_reason": "fresh"
  },
  {
   "callsign": "ZS6SRC-37",
   "flight_id": "ZS6SRC-37_2026-07-31",
   "payload_type": "WSPR",
   "seed_time": "2026-08-16 22:59:00",
   "seed_lat": -25.85417,
   "seed_lon": -110.29167,
   "seed_alt_m": 12380.0,
   "seed_age_h": 6.35,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-23 23:30:00",
    "lat": -27.31724,
    "lon": 148.62197,
    "alt_m": 12135.6
   },
   "member_spread_deg": {
    "lat": 16.37,
    "lon": 123.18
   },
   "member_spread_now_deg": {
    "lat": 0.73,
    "lon": 5.02
   },
   "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": 118.98,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-23 23:45:00",
    "lat": -9.45805,
    "lon": -32.6341,
    "alt_m": 16066.6
   },
   "member_spread_deg": {
    "lat": 14.53,
    "lon": 189.99
   },
   "member_spread_now_deg": {
    "lat": 9.03,
    "lon": 104.98
   },
   "display_as": "region",
   "display_reason": "member_spread"
  }
 ]
}