Flight Number: 970219H1 Page 1 of
Date: February 19, 1997 Aircraft ID: 42RF Scientist: Jorgensen
Event Log
Time Approx. Location Event & Comments (UTC) (Lat, Lon) Shannon This is IOP17, Flight #11 on Low 41. The mission is with the UK C-130 using coordinated legs throught the warm front, and a three leg "systematic survey" of the low center and cold front. The low is fairly close to SNN, and is expected to track 040/20 m/s 2:43:50 Shannon Engine Start 2:48:27 Block Out 2:59:27 Take Off 3:04:32 52.828 -9.246 pretty good low level jet of 90 knots at 770 mb 3:11:20 53.101 -9.700 precip on nose radar ahead - radar system not up yet 3:14:39 53.245 -9.916 radars are up-good looking bright band on the TA precip mostly below our altitude of 10k ft. 3:19:25 TA velocities are very noisy - techs are working on the TA 3:28:07 53.835 -10.866 flying through several short nw-se oriented band segments. One long band near 100 nm on LF 3:37:11 54.230 -11.538 TA seems to be working better with the new receiver 3:41:21 54.404 -11.838 begin descent to 5k ft 3:44:46 54.551 -12.084 at 5k ft tracking to pt. 1 3:50:59 TA still being worked on 3:55:00 54.980 -12.858 at pt. 1 begin leg 1 to the north 3:57:16 METMAN reports his ETA to pt. A is 0454 3:59:50 55.356 -12.839 climb to 6k ft to perhaps get some smoother air-pretty turbulent down here at 5k ft. 4:01:48 55.513 -12.796 not much better at 6k ft - climbing to 7k ft 4:02:26 TA is finally showing some signs of life 4:06:08 55.872 -12.726 finally found a little smoother air at 7k ft 4:10:39 56.257 -12.667 winds have backed around to 195 from 215 and temps have dropped at bit 4:17:37 radar system froze up again 4:19:13 56.971 -12.494 start perl #1 near warm front - moderately heavy stratiform precip 4:22:07 end of perl #1 4:26:27 57.340 -12.405 apparently going through the edge of the warm frontal band at 57 20N 4:28:53 57.522 -12.374 start perl #2 in moderate stratiform precip north of the warm front band 4:41:19 58.277 -12.194 start perl #3 in light precip 4:44:13 end of perl #3 4:45:54 58.426 -12.158 warm frontal band is well marked on the LF radar to the south about 60 nm 4:47:47 58.569 -12.127 at pt 2 end of leg 1 doing perl #4 in light precip 4:51:57 58.635 -12.236 end of perl #4 start of leg 2 4:55:42 METMAN advises that the Ops Center recommends that the pattern should be shifted north by 30 nm 5:00:04 58.452 -13.118 shifting pattern 30 nm to the north pt 3 is now 58 00N 18 24W 5:01:12 58.442 -13.254 start perl #5 in moderate stratiform precip 5:04:28 end of perl #5 5:11:39 58.370 -14.149 start perl #6 - giving sfc p reports to METMAN every 5 minutes 5:13:40 radar system froze up momentarily 5:14:22 end of perl #6 5:21:08 radara system finally back up 5:23:14 58.303 -15.259 start perl #7 in moderate precip 5:26:18 end of perl #7 5:36:15 58.186 -16.543 start perl #8 in moderate precip 5:39:32 end of perl #8 5:44:54 58.122 -17.284 two curved bands on LF one just ahead extending to the SW and the other the principal warm front/occlusion 5:49:34 58.038 -17.881 start perl #9 5:52:26 end of perl #9 5:52:45 58.078 -17.914 winds have come around to 120 degrees, but only 20 knots 5:56:43 58.017 -18.401 at pt 3 end of leg 2 executing a perl #10 6:01:06 end of perl start leg 3 toward pt. 4 6:14:13 57.603 -17.108 start perl #11 in center of bent back frontal band 6:17:17 end of perl #11 6:20:39 57.489 -16.746 broke through the inside edge of the band 6:28:55 57.199 -15.837 we're now in the warm sector as temps have jumped 5 deg and the winds have increased to 210/42 knots 6:30:34 57.141 -15.657 GPS is getting errors, switching to INE1 6:43:04 56.716 -14.598 narrow band of precip 10 nm ahead. Cold front? 6:45:11 56.637 -14.389 start perl #12 in band 6:48:21 end of perl #12 6:48:44 56.650 -14.276 through band 7:06:16 55.959 -12.613 entering heavier stratiform precip 7:07:13 55.920 -12.521 starting perl #13 in light precip 7:10:29 end of perl #13 7:17:18 55.660 -11.812 start perl #14 in moderate precip 7:20:14 end of perl #14 7:30:45 55.230 -10.834 at pt. 4 end of leg 3 - doing a perl #15 before the track to the SW 7:34:46 end of perl #15 track to pt. 4 7:50:52 54.714 -11.761 at pt. 5 turn to track to pt. 6 start of leg 4 8:25:52 56.507 -14.243 not much precip on this leg so far. LF shows what appears to be the cold front extending south from 100 nm to our south, and the cloud head region 100 nm to our north 8:29:34 radar system froze up 8:48:36 57.636 -15.942 querry to METMAN as to a change in plan to re-acquire the precip 9:01:57 58.263 -16.929 low stratiform precip blow us - upper cirrus shield above 9:16:34 58.978 -18.034 at pt. 6 end of leg 4 - orbiting in a perl #15 to hear word from the Ops Center about our change of plans to track back to the center 9:28:35 58.894 -17.904 Ops Center advises to follow the original plan, so now we're tracking to pt. 7 9:39:00 58.420 -18.754 at pt. 7 start of leg 5 10:02:41 57.540 -16.084 out of precip-climbing to 215k ft to get more tailwind and pehaps get to the cold front before it moves east of 10W 10:28:28 56.467 -13.160 It is now apparent on LF that the cold frontal precip is east of 10 W, prbably near 8W 10:46:48 55.662 -11.115 passing through a small n-s band of precip-post frontal rain? Well defined bright band at bout 1 km altitude-precip barely extends to our flight level of 15k ft. 10:53:50 55.334 -10.472 at pt. 8 - end of leg 5, turn for SNN 10:55:02 LF out-replacing receiver-back up 11:10:10 54.386 -9.873 flying parallel to band-good bright band 11:53:29 land 11:58:27 block in