Lab 0.5: Frontal Structure and Evolution
Installation of the Promontory Point NEXRAD and development
of the Utah Mesonet has allowed us to better identify and
study the structure of fronts in northern Utah. In this lab,
we use these observing systems to examine the evolution of
two fronts that moved through the region in late January 1997.
Problem 1:
Using your knowledge of the thermal wind and structure of surface
based fronts, describe and explain the velocity profile observed by
the Promontory Point NEXRAD at 1435 UTC 25 January 1997 (pictured below).
The inbound/output velocity scale (m/s) is pictured on the left with
positive and negative values corresponding to outbound and inbound
velocities respectively.
Problem 2:
On 23 January 1997, a cold front moved through northern Utah, producing
up to 6" of snow on the Salt Lake Valley floor. Using the KMTX Doppler velocity analyses for this event,
and your knowledge of cold frontal structure, explain the evolution of
the doppler velocity field.
Problem 3:
For this same 23 January 1997 event, use time series from
Salt Lake City,
Hill Field, and
Ogden Peak to identify the time of
frontal passage at these locations. Draw a vertical line on the
time series to denote the time of FROPA. Explain any differences
in the character of the frontal passage at these sites.
Problem 4:
Use mesonet station plots to analyze the cold front position
at 0600,
0900, and 1200 UTC 23 January
1997. To fine tune your frontal positions, use the 15-minute
mesonet plots and meteograms that are stored in
/web/dept/class/jimsteen/met5530/lab6_mesonet/meteogram.
