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