Flight Number: 970215H1 Page 1 of
Date: February 15, 1997 Aircraft ID: 42RF Scientist: Jorgensen
Event Log
Time Approx. Location Event & Comments (UTC) (Lat, Lon, Hdg, Trk, GS, P, Palt) 7:07:17 Shannon This is Flight #9 IOP15 on Low 38. P-3, G-IV, and C-130 will work this system. The G-IV is flying now and will return about 0930 UTC. P-3 departs 0730, and the C-130 0600 UTC. Planned patterns are three radial legs through the cloud head band to the east, north, and west of the low center. 7:15:09 Shannon Engine Start 7:19:32 52.691 -8.919 Block Out 91.8 92.0 3 1017.9 7:28:03 SNN Take off 7:29:23 52.689 -8.916 Light precip on climb out from SNN 29.6 29.5 104 994.0 7:33:49 52.688 -8.915 METMAN estimates their pt. A at 0815-about 15 min 306.3 310.7 99 ahead of schedule 745.3 2516 7:46:47 53.419 -10.144 overcast beginning to break up-can see the sea sfc 305.2 312.8 117 below a scattered low cu deck-ETA to pt. 1(buoy) is 548.9 4880 0840 or about 17 minutes behind schedule 7:55:46 53.785 -10.867 Radar recording began at 0750 UTC. The TA is 301.8 308.0 118 seeing light echo just above us a km or so 548.8 4881 8:19:18 54.904 -12.724 some precip bands on LF 300-400 km to our SW. 317.8 324.6 131 548.8 4881 8:21:56 55.065 -12.931 begin descent to 5kft-METMAN reports time to pt. A 317.7 324.5 132 0830 UTC 548.8 4882 8:26:17 55.313 -13.264 more extensive anvil deck now evident on the 317.0 322.8 136 TA-echo depth from 3km to about 8 km 693.5 3086 8:28:07 55.417 -13.407 now out of upper cloud-can see ocean sfc below-few 317.4 322.0 138 whitecaps wind at flight level 200/30 knots 760.6 2354 8:30:47 55.568 -13.617 at 5k ft. About 7 minutes out from the buoy 316.0 320.7 125 837.7 1576 8:33:54 55.734 -13.841 going by echo on the right-some convective 317.8 322.9 123 characteristics 837.1 1582 8:38:57 56.013 -14.178 over buoy turn to track to pt. 2 begin leg 1 298.5 303.5 118 834.4 1608 8:43:10 55.909 -14.546 in extensive TA echo max dBZ only about 30-small 231.0 236.8 105 convective cells left and right of track echo top 836.7 1586 5km above us 8:47:31 55.766 -14.900 arking band segment 5-10 nm ahead on nose 226.8 233.5 104 radar-weak reflectivities however 837.1 1582 8:50:25 55.675 -15.147 bright band on TA less than 1 km above the sfc 229.4 237.3 111 835.8 1594 8:57:23 55.465 -15.769 more arc band segments evident 10 nm ahead on the 233.9 242.4 104 nose radar 834.6 1607 9:00:01 55.397 -15.983 passing through band-small convective cells seen on 231.0 239.2 106 the TA 834.6 1606 9:09:30 55.080 -16.809 sfc pressure estimate agrees pretty well with model 227.6 238.0 107 for 09Z-about 1003 mb 830.8 1644 9:13:05 54.970 -17.106 through band-temps warming - warm front? precip 228.1 236.7 105 weakening on TA 830.2 1649 9:38:42 54.235 -19.046 at 0915Z the GPS began to have problems with noise. 228.0 237.0 98 Switched to INE1 for displays-another antenna 827.2 1679 problem 9:45:37 54.032 -19.568 in warm sector-band about 110 nm ahead-cold front 225.8 233.7 100 827.5 1676 9:51:29 53.850 -19.999 echo intensity on TA increasing as we proceed 225.4 234.2 101 toward pt. 2 824.1 1709 9:56:47 53.685 -20.409 small band of ~30 dBZ echo ahead 5 nm 226.4 236.6 100 824.3 1707 9:58:00 53.648 -20.497 in band now-mostly stratiform 224.3 233.9 99 824.4 1706 10:01:33 53.537 -20.757 out of the band now. Another band 10 nm ahead 223.9 235.1 98 (cold front location?) 824.5 1705 10:04:09 53.460 -20.944 begin perl #1 in band 230.0 241.1 101 821.6 1734 10:07:12 53.492 -20.969 end perl #1 - resume southwest track to pt. 2 221.6 233.3 101 821.5 1735 10:11:40 53.350 -21.261 winds beginning to increase in speed as we approach 219.3 230.8 92 the frontal band - LLJ? 821.7 1732 10:14:47 53.251 -21.459 temps beginning to decrease a bit 220.0 228.8 94 821.8 1732 10:16:08 53.207 -21.548 sea sfc has many whitecaps 225.1 232.7 96 821.5 1735 10:16:36 53.192 -21.580 entering frontal band 225.3 233.3 96 821.7 1733 10:22:20 53.016 -21.969 at pt. 2 - completed leg 1 - turn to track to pt. 3 224.3 234.6 93 819.6 1754 10:26:41 53.101 -22.392 Ops Center suggests moving pt. C (our pt. 3) 1 283.9 293.8 120 degree farther west based on sat imagery-but Sid 817.7 1772 wants to stay near the region of max descent so we'll stick with the original plan 10:28:08 53.139 -22.538 flying near the base of the thick anvil-echo tops 283.6 292.9 120 about 4 km above 817.7 1772 10:42:09 53.491 -23.954 at pt. 3 - start leg 2 - in clear air - thin 290.6 297.5 122 overcast cirrus above - clouds visually slope up to 814.2 1807 the north 10:46:28 53.783 -23.838 back into the TA echo again 19.2 19.3 135 814.4 1804 10:55:48 54.427 -23.474 winds have decrease to 20 knots as we go north - 20.3 18.7 131 low center split as model suggests? 814.6 1803 11:03:54 54.982 -23.149 winds strengthening again now 180/46 knots 22.8 18.4 138 814.6 1803 11:10:24 55.437 -22.864 shallow precip below us-rising just to flight 25.1 20.5 135 level-band of extensive precip evident on LF about 814.6 1803 60 nm ahead 11:20:06 56.117 -22.429 more intense echo on TA now-well marked bright band 22.5 18.8 142 just above us 814.7 1802 11:22:12 56.267 -22.337 start perl #2 in stratiform precip-occlusion zone? 13.9 13.7 145 814.6 1803 11:25:10 end of perl resume 020 track 11:28:42 radar data system froze up 11:30:06 radar system back up 11:30:36 56.722 -22.043 much more intense precip now-winds are also 28.3 20.5 147 starting to back to east and temps beginning to 818.3 1767 decrease 11:33:06 56.904 -21.920 starting perl #3 to the right in heavy stratiform 31.3 21.9 141 precip 818.1 1768 11:36:09 end of perl - resume 020 track 11:39:06 57.170 -21.785 temperature is steadly decreasing along this track 34.7 21.6 132 - now -2C 818.2 1767 11:41:12 minimum sfc Press seen at 1135 UTC 11:45:13 57.538 -21.499 start perl #4 in stratiform precip-bright band now 22.8 11.4 124 close to the ground 819.8 1752 11:48:01 end of perl - resume 020 track 11:53:20 57.871 -21.298 exciting out of the north side of the band - precip 37.7 26.0 118 decreasing on nose radar 822.3 1726 11:59:20 58.225 -21.041 at pt. 4 end of leg 2 turn to track to pt. 5 328.3 325.3 137 822.4 1726 12:01:02 radar system froze just before pt. 4 12:02:03 58.260 -21.401 radar system back up again - start perl #5 in 271.7 275.5 137 moderate precip 822.3 1726 12:05:19 end of perl resume track of 274 to pt. 5 12:20:14 58.399 -23.554 start of perl #6 in moderate precip-interesting 262.3 266.9 138 sharp shear layer about 4 km above us 822.4 1726 12:23:48 end of perl resume track to pt. 5 12:31:51 58.480 -24.860 temps dropping off to -5C now - the bright band has 277.7 276.2 138 all but disappeared into the ground 822.6 1724 12:34:09 58.497 -25.187 at pt. 5 start perl #7 in moderate precip 268.1 268.4 137 822.4 1725 12:40:12 end of perl start leg 3 through the occlusion band 12:50:29 57.828 -24.918 start perl #8 in heavy precip of occlusion band 206.7 217.2 134 822.5 1724 12:53:10 end perl #8 12:56:03 57.636 -24.813 exiting precip band going ESE 149.6 162.6 109 822.3 1726 13:01:17 57.356 -24.641 out of precip - end of leg 3 turn to trk 210 to cut 158.8 166.3 101 a little time off the next leg through the bend 822.3 1727 back front on the west side of the low 13:07:11 METMAN reports good looking sonde cross sections through the cold and warm fronts on their first two legs 13:08:57 56.957 -25.031 TA is seeing upper level cloud deck 2 km above 203.1 208.3 111 us-good radial velocity structure all the way to sfc 813.0 1819 13:16:58 56.530 -25.468 end of leg turn to track to pt. 7 start of leg 4 206.8 211.6 112 through bent back region 812.0 1828 13:25:28 56.705 -26.447 Going through a field of small convective 289.2 290.5 128 cells-must be near cloud top as the turbulence has 811.7 1832 increased 13:29:30 radar system froze up again 13:32:54 radar system back up 13:37:23 56.990 -27.953 at pt. 7 - end of leg -climb to 10k ft for trip to 324.3 308.2 120 buoy 812.6 1823 13:38:30 57.025 -27.922 sloped isopleths on the raidal velocity display 85.3 92.8 98 780.2 2151 13:45:49 56.998 -27.160 TA shows some wild velocity structure in the upper 97.2 94.8 114 levels of the bent back region 694.6 3073 13:55:58 56.955 -26.015 still in moderate precip-good radial velocity 98.1 94.6 117 structure 694.8 3071 14:04:09 56.920 -25.066 precip intensity increasing winds shifting to 99.1 93.2 120 southerly 694.8 3071 14:14:18 56.867 -23.909 bright band is now 1-2 km above the ground in the 106.2 95.0 117 warm sector 694.8 3070 14:18:47 METMAN to track south through the low center 14:45:47 56.631 -20.371 still in very extensive stratiform precip as we 108.3 97.2 115 track eastward just south of the occlusion front 695.1 3068 14:55:25 56.539 -19.307 finally breaking out the precip-sun is out-thin 109.5 99.6 118 overcast above and thick overcast just below our 695.1 3068 flight level of 10k ft. 15:24:28 56.194 -15.940 turbulence as we encounter some shallow 112.6 103.2 121 precipitation. Echo tops are only to flight level, 694.7 3072 with a strong bright band in evidence. 15:32:54 56.068 -14.938 still within light precip to flight level. Some 113.2 104.6 130 turbulence too. 695.0 3069 15:34:54 56.034 -14.684 more intense precip now. Multiple layers on the TA 111.3 102.7 126 695.0 3069 15:38:38 55.980 -14.258 over buoy-turn to track to SNN-climb to 15k ft 118.8 109.0 125 695.0 3068 15:41:48 55.844 -14.018 very intense precipiation now-bright band in excess 148.4 141.1 115 of 35 dBZ 617.3 3989 15:53:11 55.246 -13.187 flying parallel to a band that exhibits a strong 152.3 141.5 121 north south slope to the reflectivity 571.2 4580 15:59:31 54.908 -12.736 exiting the precip 153.4 143.1 126 571.2 4580 16:16:46 Radar Recording Halted 16:35:07 53.157 -9.653 begin descent into SNN 135.3 126.6 135 605.2 4141 16:52:11 Land SNN 16:56:54 Block In