Mission 13, 29 Sept 2001
ITCZ mission C130 only
Darrel Baumgardner - flight scientist
Dave Raymond - mission scientist

Conditions Huatulco - high thin overcast, towering cu over mountains.

1430 - C130 launch.  Weather in box: Old development SE propagating
NW.  NS line developing 94 W over full box dimensions.  Suppressed
west.  Initial point: 95 W, 11 N.
1439 - Strong whitecaps.  Winds at surface appear to be from E.
1445 - Will drop dropsonde.
1449 - No Wards.  260X fixed.
145050 - Drop 1.  Near 96 W, 14.6 N.  Report 42 kt winds 1500 ft.
1458 - 14.1 N entering EW line of deep convection.
1501 - This line is mainly stratiform here.
1505 - No whitecaps to speak of s of this convective line.
1511 - Drop 2 - 13.5 N.  14 kt winds surface.
151410 - Do some S turns to test roll dependence of Ophir.
151621 - End S turns.
1526 - Drop 3, 12.5 N, winds 9 kts fro 160.
1531 - 12.1 N.  We have a layer of clouds below us now.  The
region we just went over is not growing to depths beyond 13000 ft.
1539 - Still layer clouds below us.
1545 - 11.1 N -- back into region of lots of small cu, occasional
towering.
1548 - 95 W, 11 N, new heading 240.  Drop 4.  Getting a few whitecaps.
1555 - Over broken small cu sheared from N.  Heading for region of
deep convection.
1600 - Drop 5.
160144 - Penetrating apparently dead tower with tops just above us.
Very weak bumps.
1603 - In lots of layered clouds above and below.
1606 - Drop 6, 96 W, 10.4 N.  We are in a region of moderate convective
cells.
1607 - Climb to 18000 ft still going WSW.
1618 - At 18000 ft, heading for cell with tops a few thousand feet
above us.  This has a ``hard'' appearance and is probably typical
of cells making the mess of stratus around us.
1627 - No bumps in this thing.
1638 - Drop 7, 98 W, 9.3 N.  Start descent heading SW [due to iceing
of radome].  This thing is a mystery -- no convection that we can
detect, but lots of stratiform.
1641 - Radome iceing -- descending.
1646 - Turning L at 10000 ft.  Will return thru system at 8000 ft.
1654 - We not that right Rosemont is messed up.
1730 - Lots of whitecaps from W.
1735 - In clear -- we have lots of trade cu -- we'll go over them
cross wind dropping sondes at 8000 ft, do passes at 3000 ft, 1000 ft,
and 100 ft.
173950 - Drop 8 in trade cu area.  Surface wind 11 m/s 225.
174213 - Penetrate top at 8000 ft.
174654 - Drop 9.  8 m/s 216 at surface.
1748 - Penetrated another cloud.
175113 - Drop 10.  6 m/s 230 at surface.
1752 - Do 90/270, drop to 3000 ft over little clear patch with no
whitecaps.  E end of leg is 94.4 W, 11 N.
1802 - Sampling clouds at 3000 ft.
181039 - do 90/270 and drop to 1000 ft.  Good whitecaps this end.
1814 - At cloud base at 1000 ft.
1820 - As we go east, the cloud bases are rising, whitecaps decreasing.
1827 - End of run -- descend to 100 ft and return W.
1850 - Starting sounding, 90/270 back over previous track.
1902 - Thru cloud we probably have been thru before, turning NW at
13000 ft.
1907 - Turning N to study vast mass of deep convection.  Drop 11.
1915 - Climbing to 18000 ft do do N/S passes on E/W convective line
near 12.5 N.
1919 - Doing at 360 in climb so that we start 18000 ft traverse far
enough from cloud [to realize Ophir calibration].
1921 - Drop 12, surface winds 4 m/s 190.  Tops are well above us,
but not really deep.
1927 - Descending to 13000 ft.  Drop 13 [N side].
1933 - Headed for line at 13000 ft.  Drop 14.
1939 - Down to 8000 ft.  Missed convective core at 13000 ft [since
they are hard to see from N side].  The south side of this line is
the side with growing cu.
1944 - A few whitecaps on S side.
1955 - Down to 3000 ft N of line.  No whitecaps.  It is clear below
right up to N edge of line.
2005 - Down to 1000 ft S of line.  Appear to be a few hundred feet
below cloud base.
2015 - Down to 100 ft N side of line.  The line has weakened as we
worked it.
2024 - Under trade cu.
2025 - Starting sounding to 13000 ft, heading for 98 W, 12 N to see
if there is a cyclone spinning up.
2040 - 13000 ft.  Drop.  Alreading getting into a region of layer
clouds.
2053 - Drop, 97 W, 12 N (bad).  Head S based on flight level winds.
2056 - Drop.
2059 - In bumpy stratiform rain.
2101 - Red ahead on radar.  Steady rain.
2109 - 97 W, 11 N.  Turn to heading of 45.  Drop.  This is a very
strange creature -- a large mesoscale area of nearly solid cloud,
lots of rain, and a cyclonic circulation.  However, it is not very
deep -- say, 7-8 km at most, from visual obs.  This smells like an
incipient tropical storm.
2128 - Still in stratiform cloud at 13000 ft.
2130 - Out of stratiform.
2133 - Stratus above and below, convective line ahead.
2142 - Heading through a very stratiformy area of convection.
2150 - Through line, lots of low layer cloud.
2154 - Solid undercast, just some scattered stratus/cirrus above us,
no convection to N.  Drop at 14 N.
2206 - Lots of whitecaps.
2210 - Begin descent on approach.
2216 - There is some convection over the mountains, but not much.
Stratus clouds over Isthmus.
2233 - Recover Huatulco.