Jim, I assume you mean that you would be using a Bellamy method
or similar triangulation technique to compute vertical motion
within a triangle formed by 3 balloons released by the M-CLASS.
The problem as I see it is "how will you know whether you have
found the MAXIMUM vertical motion, which is required in your hypothesis
as it is stated? Even supposing that you could unambiguously locate
a maximum (which is impossible with just a few balloons), how
then would you be able to determine that its cause is definitely
the low-level jet? Please explain your thinking here.
Steve, thanks for the good comments. We know very little about
the initiation of elevated convection and TIMEX provides a good
opportunity to investigate it. My hypothesis is primarily based
on my 3-4 June PRE-STORM work, which is also applicable to other
similar synoptic situations (e.g. 6/6/93).
Yes, I figured we could use a Bellamy method using three (or
more) wind profiles to compute vertical motion. Aircraft, NEXRAD,
and profiler data would also be valuable. My gravity wave analysis
of the 3-4 June event (based on what you did for the CCOPE case)
was inconclusive - the 5-minute resolution of the PAM data and
the lack of usable data south of the KS border prevented unambiguous
tracking of the waves. It was clear that once started, convection
caused gravity waves. There does seem to be a link between the
LLJ and convective initiation in that case, so the LLJ would be
something that a mobile observing crew could concentrate on.
Some of the things I'd like to know are, 1) how does the LLJ
interact with the sloping frontal surface? 2) Does the LLJ have
a terminus as Trier and Parsons show, (i.e. does it just end abruptly
with enhanced upward motion?), 3) what is the source air for the
elevated convection (this is crucial for proper modeling). Also,
is there any truth to the forecasting axiom that elevated convection
forms along the 850 mb front?
I don't think there are any meso-beta-scale observations in the
vicinity of elevated convection. I would hope that we might find
enhanced vertical motion near where the convection initiates and
the most likely spot for that would be near the LLJ. Granted,
that an observation of vertical motion will not tell us whether
it is a maximum, but we do stand to learn about the meso-beta
structure of the frontal surface. The observations can also be
used in a 4-D variational analysis system to "fill in the gaps".
Attributing an observation of vertical motion to a given physical
process (such as the LLJ, or gravity waves, or frontogenesis)
is more difficult and will take some thought. For this task 4DVAR
I expect that analysis of NEXRAD and profiler data (and maybe
4DVAR) prior to the experiment could refine the approach. Anyone
want to fund that?