NASArolls 20040131
Crew:  Fagerstrom, Kelly, Leon, Oolman

1346 start engines.  Have classic lake effect situation with NWly winds,
and temperatures along the Wisconsin shore at -5 to -10F.  The stcu starts
well offshore now as there is more ice at the surface.

The flight plan is to work three lines over near the Michigan shore, oriented
along, across, and at 45 degrees to the wind (calling it 310 degrees from the
GRR radar).  GRR radar indicates the clouds are quite shallow and mostly
cellular, with occasional indications of roll alignments.

1356 takeoff
Over first few miles of cloud, along the upwind edge, many of the cu tops
that are bulging upward (updraft obviously) appear to have wave-like
features concentric to the center of the bulge.  An analogous appearance
would be to drop a beach ball into the water and look at it from below,
with ripples moving away from the ball.  We were going to try to fly
through them at the end of the flight, but the convection had weakened
so much they were no longer there.

1412 F1-F2 at 4000 ft msl, radar down dual.  This is the cross-wind line.

1423 F2-F1 at 2200 ft msl, side dual, cloud tops about 3100 ft msl.

1424 move down to 1800 ft msl to minimize the times when aircraft roll
tilts the side beams out of cloud top.  Can occasionally see the lake surface,
which is relatively calm conpare with other days.  Also see occasional
patches of sunlight reaching the surface.

1424  F1-F2, 500 ft agl, radar up+side-slant.  Cloud bases relatively
well defined.  Several different evidences of light snowfall:  2DC
buffer updating, sunlight shafts visible between cloud base and lake.

Mini-sounding in the transition to G2.

1447 G2-G1 4000 ft, down dual.  This line is oriented at 45 degrees to the
wind.

1457 G1-G2 1800 ft msl, side dual.

150007 and 150336: sizable holes in cloud.

1507 G2-G1, 500 ft agl, up+side-slant.

Mini sounding in transition to H1.  On this and subsequent soundings, see
interesting and VERY puzzling profile of water vapor mixing ratio.  The thetaE
profile is classic:  nearly constant from cloud top down, sharp inversion layer
from cloud top up.  However the water vapor was about 0.25 g/kg both in the
BL and above cloud (to a few hundred feet below 4000 ft msl), with a sharp
decrease to about half that value just above (I think) cloud top:
                   
                   |                  *
                   |                  *
                   |        *
                Z  |             * 
                   |                  *  cloud top, I think
                   |                  *
                   |                   *
                   |                   *
                   |___________________________
                               h2omx                                   

1518 H1-H2 4000 ft, down dual

1530 H2-H1, 18000 ft, side dual.  Several changes occuring now, including
decreasing wind speed, decreasing echo strength, decreasing horizontal echo
coverage, higher cloud bases, etc.

1538 H1-H2 500 ft agl, up+side-slant.

Cllimb back up to 4000 ft msl for return to Racine.

1608 land