Flight Number: 970125H1 Page 1 of
Date: January 25, 1997 Aircraft ID: 42 Scientist: Jorgensen
Event Log
Time Approx. Location Event & Comments (UTC) (Lat, Lon) 19:51:31 Shannon Engine Start 20:00:45 Shannon Problem with #4 engine starter - perhaps 1 hour delay 20:41:31 Shannon 2nd try on the engine start 20:45:22 Block out 20:53:01 52.710 -8.909 Take off - will try to fly original pattern 21:00:21 Radars up, running, and recording 21:14:01 53.514 -10.843 Contact with METMAN 59 21:14:32 53.536 -10.904 Sea clutter pattern on LF has NE-SW line about 50 nm ahead - maybe change in sea swell or perhaps rainband. Definite rain echoes beyond out to 100 nm 21:33:42 54.252 -13.007 Course change to track to buoy 21:44:22 55.021 -13.546 Echo evident on TA at our level up to 1 km above. Very weak echo but good velocity signature 21:49:12 55.371 -13.785 Begin descent to buoy at 56N 14.2W 21:55:33 55.807 -14.094 at 5kft tracking to buoy Temp is 4.4C winds 224/30 so we're on the warm side of the cold front 21:58:10 55.961 -14.201 at the buoy - turn to track to point 1 at 53.5N 14.2W 22:05:27 55.778 -14.704 apparently the precip associated with the front is still 70 miles to the NW - oriented in a line from SW to NE. May have to change pattern to track NW to the front. 22:25:36 55.004 -16.063 Giving up on the survey pattern as the forecasted position of the front is about 60-70 miles to our NW 22:29:48 55.166 -16.386 we are now tracking 315 to front which is about 30 miles ahead. Estimate for postion of front 55 50N 17 30W. Front extends NE from there 22:33:12 55.324 -16.644 second precip band 50-60 miles to the NW of what we think is the frontal band. 22:36:31 55.476 -16.895 contact with N49, said they dropped 44 sondes 22:38:24 55.559 -17.035 starting to enter precip zone of band. Small embedded convective cells out to 40 nm ahead. 22:45:00 55.867 -17.545 tracking on 315 past what is evidently a pre-frontal band toward the other band about 60 miles ahead 22:47:47 55.990 -17.754 some turbulence but no wind shift as yet 22:50:15 56.099 -17.946 temperature decreasing - now down to about 1C 22:58:19 56.472 -18.572 leading edge of front 10 miles ahead - near 57N 19 30W 23:00:13 56.560 -18.725 weak stratiform precip showing on TA 23:03:15 56.699 -18.966 winds shifting to easterly 23:05:09 56.784 -19.113 winds now 330/7 and temps have dropped to -7C so through front but is still rather moist - 90% RH 23:08:27 56.928 -19.342 still in rather extensive stratiform precip but dBZ only about 20 23:10:22 56.993 -19.452 turning around to get back to precip at front - precip decreasing as we go NW 23:16:15 56.744 -19.107 back into stratiform precip 23:18:14 56.656 -18.935 turning to NE in middle of precip band 23:21:37 56.775 -18.676 perl #1 to the left in middle of the band 23:25:25 end of perl #1 23:29:15 can't contact 308D 23:36:51 57.313 -17.762 perl #2 to the left in light stratiform precip 23:37:21 57.335 -17.731 asked METMAN to try to contact 308D, also asked them to relay e-mail to Ops Center and ask what time 308D got off the ground 23:40:06 end of perl #2, resume 042 track 23:47:18 METMAN reports 308D got off at 2343 Z 23:53:12 57.980 -16.859 end of leg - start perl #3 and climb to 8000 ft for return leg to SW in the middle of the band 23:57:39 58.032 -16.908 must have gone through the top of the front winds now 219/46 and temps -6C 23:58:19 end of perl #3 resume tranck down the middle of the band trk=218 0:10:12 57.512 -17.683 perl #4 to the left 0:11:07 53 46N 11 28W 14kft 308D position 0:13:19 end of the perl #4 0:23:10 57.100 -18.299 end of leg, do perl #5 as we descend to 5kft. Setting up box from here too 100 miles NE, 20 miles wide 0:27:29 57.063 -18.222 end of the perl #5, turn to track 118 10 miles to get to SE corner of the box at 58 20N 57 18W 0:32:19 58 20N 57 18W start of leg to the NE 0:33:58 contact with 308D passed information about pre-frontal band and the cold front that we are working 0:52:29 Reseting radar system for possible problem. Only see reds, blues, and white contours on Vr display. 0:57:35 58.328 -16.029 end of leg. At NE corner of box, turn to track across line 20 miles 1:00:36 58.436 -16.247 radar system down to reset TA. 1:03:47 58.535 -16.531 end of leg, at NW point of box, turn to track 210 1:08:51 308D just went through pre-frontal band, continuing to track to frontal location 1:11:43 still messing around with the TA radar 1:18:23 57.836 -17.121 at southern end of the band, trk 120 to cross it 1:20 at SE corner point trk 50 1:36:25 308D reports sfc position of front back at 14W where we saw the "pre frontal band" Apparently front has a very shallow slope 1:39:05 TA system down while new transmitter is installed 1:45:05 58.746 -14.618 our band is very weak and we 1:48:05 58.864 -14.347 end of the north run, turn to NW to cross what remains of the band. TA radar back on but the colors still look odd 1:55:15 TA back working, apparently a loose connection on the IQ video cable 1:55:39 59.152 -14.877 end of leg, turn to trk 228 back to the SW on west side of band 1:59:49 switching to original TA receiver 2:01:24 58.931 -15.364 at least three parallel bands now, spaced about 10 miles apart very weak reflectivity 2:10:59 58.557 -16.165 end of leg, turn to track to the new target near 13.5W 58.5N 2:21:14 58.393 -14.937 winds have dropped off and now SW 2:27:06 will track to what appears to be sfc position of front, and track down the middle of the relfectivity maximum for 80 miles. ETA 2:30:53 58.260 -13.850 in the middle of the band. Trk now 222 to the SW. 308D going east-west along 57.6 working the same band 2:33:11 58.169 -14.017 perl #6 in middle of band. Not much precip 2:36:25 end of perl #6, resume 230 track down the band 2:47:35 57.706 -15.078 at least 7 weak NE-SW oriented bands are evident on the LF spaced about every 10 nm or so. 2:56:23 57.432 -15.685 turbulent, and winds have shifted back to southerly going through top of front? 3:00:19 57.283 -16.011 end of leg, turn to track to buoy 3:09:00 56.869 -15.454 wind and temperature graphs mark the location of the waves we're going through. Another strange NE-SW minima of reflectivity on the LF display 25 miles ahead. Near the buoy. Check the buoy data for this time. 3:12:59 56.676 -15.188 chip light on #3 engine. Returning dirctly to SNN. 3:14:12 56.623 -15.091 climb out of 5kft to cruise altitude. 3:29:57 55.940 -13.857 C-Scat shows sudden sea swell direction change from northerly to southwesterly coincident with a band of weak convective cells which probably marked the surface position of the cold front. 3:41:38 55.374 -12.916 multiple bands 70-100 nm ahead on LF. Reflectivity max to 30 dBZ. Must be very shallow features as they disapear as we approach. 3:56:51 54.626 -11.755 good look at the cold air bands behind the front by enhancing the LF refectivity scale 3:58:37 radar recordiing suspended 4:33:13 52.670 -9.934 descending into SNN 4:53:13 touch down 5:02:50 block in