Flight Number: 970204H1 Page 1 of
Date: February 4, 1997 Aircraft ID: 42RF Scientist: Jorgensen
Event Log
Time Approx. Location Event & Comments
(UTC) (Lat, Lon)
5:46:07 Shannon Engine Start
5:51:36 Shannon Block out
Dropsonde antenna fixed. Will try a test sonde on the
ferry back. This is flight #6, IOP 10
6:00:39 52.709 -8.909 Take off
METMAN: pt 1: 51 54N 13 42W 0702 Z 48 30 11 24W
6:30:53 308D and METMAN estimate their pt. 1 at about 0700.
We're slowing down a bit to get there near 0652. Will
need to spiral down to 5k ft when we get there
6:32:17 52.324 -11.534 No echo showing on LF to the SW
6:53:50 52.080 -13.163 at pt 1 descent spiral to 5k ft for 1st run
6:59:34 52.096 -13.077 start leg 1
7:01:54 308D started run at 0700
7:13:15 51.257 -12.493 LF shows precip cells 150 nm ahead near our turn point
7:30:02 50.248 -11.721 LF shows precip band now near our turn point oriented
ENE-WSW
7:34:17 49.993 -11.538 small convective type storm about 10 nm ahead on nose
radar. Lvl 2 dBZ
7:36:24 49.867 -11.447 Small storm now showing on TA. Tops only a km or two
above us
7:41:13 since expected wave development is expected north of
the band, we'll stick with the pattern as drawn up
7:44:00 49.413 -11.122 sfc pressure has been rising slightly as we go south,
so the legs are set up well with respect to the
pressure trough
7:44:53 49.361 -11.085 upper cloud deck is more evident on TA as we go south
7:47:58 49.173 -10.954 now in stratiform rain region, which was seen on LF
earlier. Weak bright band, very good velocity
structure
7:53:06 METMAN60 advises pt 2 at 0757
7:54:39 48.776 -10.680 at end of leg at pt 2, perl #1 to the right in light
stratiform precip
7:55:00 0818UTC for 308D to pt 3
7:59:20 48.736 -10.738 perl #1 completed, now tracking 264 toward pt 3
8:10:37 48.612 -11.655 beginning to break out of precip region
8:17:41 METMAN reports Ops Center 51 30N 17 30W at 12Z PV
anomoly
8:19:20 48.493 -12.371 at pt 3 turn to trk 355 to pt 3 - start of leg 2 - ETA
for pt 4 0915 Z
8:22:23 0912 ETA for 308D to pt 4
8:33:13 49.375 -12.483 see a blob of precip on LF near 48.5N 16.5W
8:48:15 0916 ETA for METMAN to pt 4. Their sondes are
apparently working well with an improvised launch
procedure.
8:57:04 50.875 -12.661 16.5W 50W expected precip and cloud head max at 10Z
from Ops Center relayed via satcom from METMAN. That
position is about 3 degrees of longitude west of our
anticipated precip max location at 10Z.
9:15:44 308D at pt 4
9:16:39 52.118 -12.840 at pt 4, turn to trk to pt 5
9:18:34 0934 ETA for 308D to pt 5 - our ETA also 0934
9:21:17 52.060 -13.265 winds here are 312/17 - down near the middle of the
last leg the winds were 256 - convergence zone? Sfc P
1012 mb here.
9:26:42 51.978 -13.778 no precip evident on the LF
9:34:34 51.852 -14.525 at pt 5 turn to trk 147 to pt 6 on leg 3. 308D also
turned at same time
9:38:16 51.643 -14.373 blob of precip near 50N 16.5W which is close to the
region where the Ops Center reported the models
forcasted a "cloud head" region of the developing wave
10:14 Changing pattern to jump 50 nm on the other side of
the Electra for new pt 7. Setting up a coordinated
run to the north through the middle of the cloud head
band. Now tracking SW to new pt 7 at
10:27:39 49.120 -14.031 Comma head shape to the precip zone 100 nm to our NW
10:31:43 Will go north with Electra 50 nm to our east at 1101 Z
10:46:43 48.471 -15.285 Going through zone of small convective cells
10:48:30 48.366 -15.484 Looks like a very narrow (5 nm wide) squall line on
the east flank of the cloud head band oriented NE-SW.
At 50 nm range on the LF it has specks of 40-45 dBZ
10:59:41 48.017 -16.142 at new pt 7, trk 355 to new pt 8 start of leg 4
11:01:10 48.068 -16.204 now tracking northbound
11:13:12 48.811 -16.453 perl to the right near the end of the squall line
11:15:41 end of perl resume northbound track
11:17:38 308D and P-3 nearly braceted the line
11:35:50 estimate time for mid-run time of 1243 for next leg
(pts 9-10). Estimated end of that leg 1320 Z
11:42:34 50.489 -16.727 prematurely cutting this leg short to cut over to new
leg 9-10. Trk west to 17 30 lthen back SW to new
point 10
11:50:23 50.511 -17.435 end of the westbound track-turning SE to new point
10-start of leg 5
12:00:41 308D completed pattern and is on its way back to SNN
12:02:22 49.843 -16.884 winds are picking up as we track to the SE
12:14:11 49.164 -16.280 going though a field of shallow convective cells that
show a highly sheared appearance on the TA.from SE to
NW
12:18:01 49.164 -16.280 A different appearance to the character of the LF sea
return across the squall line. We're now passing
through the SW end of it and the sea reture blooms to
the south, but virtually non-existant to the north.
12:26:41 49.164 -16.280 Broke though the line. Wind speeds have dramatically
increased to 45 knots from 15 knots
12:34:25 48.016 -15.307 at pt 10 end of leg 5 and end of the systematic
survey. Will now track 045 to intercept the line.
12:36:30 no precip on TA since we cut though the line
12:40:19 48.296 -14.884 going through a few shallow cells on the south side of
the line
12:52:34 49.110 -14.652 through line turn to trk 045 behind the line
12:56:00 49.273 -14.398 lots of stratiform precip this side of line -
turbulence and some embedded convective cells
12:58:37 cloud head band has become detached from the squall
line
13:00:24 49.477 -14.079 wave type structuires at the tops of the TA echoes
13:10:10 49.842 -13.246 the convective part of the line has weakened
considerably-not much indication of the comma head any
more.
13:12:00 49.922 -13.114 turn to trk 145 to get on the front side of the line
13:21:28 49.513 -12.396 ahead of the line now-end of leg turn to trk 225
13:23:18 line now looks very ragged-just blobs of 35 dBZ cells
13:30:08 49.153 -12.852 turn to trk 255 to follow the line to the west
13:40:19 49.009 -13.647 end of sw bound leg, outside turn and climb to 6 kft
for run north
13:44:08 49.013 -13.531 start northbound run at 6k ft
13:47:40 49.249 -13.531 climb up to 7k ft to get past 0 degrees temp
13:58:02 49.941 -13.519 end of leg descend back to 5k ft and track to the
buoy-will do a spiral ascent at the buoy and then
release the sonde for a test
14:03:40 50.269 -13.449 no precip echo on the TA-large region of stratiform
precip to the rear-now tracking 007 to the buoy
14:15:44 51.032 -13.297 at buoy-performing spiral ascent to 23k ft
14:26:09 50.986 -13.415 at 232k ft
14:30:55 50.975 -13.383 sonde away over the buoy
14:39:28 perfect sonde drop
14:46:47 about a 75 knot tailwind on the way home
15:14:41 52.705 -8.918 land
15:20:10 Block In