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