From: Wen-Chau Lee
Subject: VORTEX ELDORA REPORT #2



Hi, everyone:

Jeff Keeler requested that I send my VORTEX report to all_rsf and all_rdp.
I will do it from this report. 


                     VORTEX ELDORA REPORT 4/19/95

ELDORA collected another 10 Gbyte of data yesterday. The fore HPA
(high-power amplifier) reported a coolant problem near the end of the
flight. Craig and Tim are looking at the problem this morning.

The forecast called for a marginal day for tornadoes on 19 April 1995.
The warm front was in central TX. There was a concern that the low
level moisture would not recover in time for the afternoon convection.
However, this is a day too good to pass up. The plan was for the
aircraft to take off around 1-2pm. Ground chase teams were deployed to
between Wichita Falls and Lubbock TX.

The P3 had an engine problem at 1:30. Electra was put on hold hoping
P3's engine could be fixed. A tornado warning for northern TX forced
Electra to take off around 2:30 CDT without P3. Electra flew from OKC
to Childress, TX, and turned south. Near 3:00 CDT, a tornado was
spotted south of Lubbock TX. Between 3:19 and 3:24, Electra flew
perpendicular to a series of wave clouds where theta_e oscillated
consistently with the cloudy and clear region. P3 took off around 3:30
and headed toward this region. At 3:30, Electra approached the
northwestern side of a supercell. The vertical shear of this storm was
quite large.  Electra circled around the southern side of the storm to
be positioned on the southeastern side of the storm (the optimal
quadrant for hook echo and tornado). The storm structure was very
similar to the storm two days ago with BWER (bounded weak echo region)
and other neat reflectivity and velocity structure. ELDORA ran
dual-PRT mode with Nyquist velocity +-79 m/s. Two hook echoes were
identified on the nose radar display. Lower cloud bases were also
visually observed. However, a tornado never developed.

At 4:15, Electra was in between two supercell storms. Several
penetrations allowed ELDORA to sample two storms simultaneously
(storms off both sides of the aircraft).  As Roger Wakimoto stated
"Two storms for the price of one". These two storms closed in on
Electra. The Electra left the region to join P3 and ground chase
teams, then work on the northern supercell. P3 and Electra flew at two
different altitudes and ran race-track legs. Radio communications
improved but were not ideal. Both planes left for a dry line near
Abilene TX.  The dust storm behind the dry line reached almost 10000
ft. It was an amazing scene of a line of Cb trailed by a huge area of
brown dust storms.  Electra flew to the east side of the dryline and
then worked with P3 to practice the formation flight pattern with P3
leading Electra 5 miles at the same altitude. Pilots seems comfortable
with this formation and it will be implemented on the next VORTEX
mission.

At 5:30, only stratiform rain around. We tried to turn on teh
real-time CAPPI.  It failed miserably and we were only be able to
restore the aft radar after that.

In summary, this was a good mission. Unfortunately, no tornado was observed.
We are busy processing data (now the total is 20 Gbyte). Some of you may
have seen the first ELDORA movie loop created by Bob and myself. I apologize
for the 90 degree rotation of the image. Blame xwd for this mess. Bob and
I will reproduce this movie loop so you don't hurt your neck or don't have
to turn your monitor 90 degrees to view it.    


Wen-Chau Lee