This assignment examines the evolution of a cyclone that developed over
the midwestern United States during October 1996. Synoptic surface
analyses and NCEP-Rapid Update Cycle gridded analyses will be used
to examine the frontal structure and precipitation distribution of the
system. Because this is a time consuming assignment, it will be
graded as 2 labs. Parts 2 and 3 are open-ended essay questions that
should be carefully researched and thoroughly answered.
Part 1:
Analyze the surface frontal structure at 0900 UTC 17 October and
0300 UTC 18 October. 11x17" postscript files with plotted surface data
are available in /home/meteor/x/class/jimsteen/met5540/17oct96/obmaps
and can be plotted out on the HP 4MV printer in the INSCC building (use
lpr -Plj4mv).
Your synoptic analyses should cover the area between 30N, 105W and 52N,
80W and include:
- contours of sea-level pressure every 2 mb
- red contours of temperature every 4 C (on transparancy paper)
- green shading to identify regions of precipitation (on
transparancy paper).
Synoptic analyses at intermediate times (every 3h) are hanging on the
maproom wall and should be used to piece together a consistent frontal
history (note that we did not receive surface data at 0000 UTC 18 October).
Meteograms for every station in the central United States have been stored
in gif format in /home/meteor/x/class/jimsteen/met5540/17oct96/meteogram
and can be viewed with xanim [use xanim XXX*.gif where XXX is the 3-digit
station ID]
Part 2:
Describe the distribution of precipitation and clouds during
this event (IR loops are available in /home/meteor/x/class/jimsteen/met554017oct96/sat).
Is this distribution consistent with the Norwegian cyclone model?
Is there a strong relationship between the surface frontal positions
and the distribution of precipitation?
Part 3:
Using the 3-hourly RUC analyses and forecasts grids (available
in /home/meteor/x/class/jimsteen/met5540/17oct96/ruc), thoroughly explain the
causes of precipitation during this event. Important questions
that should be answered include: What is the cause of
the convective activity northward and westward of the polar front?
What is organizing the distribution of precipitation on the
synoptic scale?
