Qualitative Surface, Radar
and Satellite Data
The following sections
provide access to a large amount of radar, satellite, and surface observations
for the time period of the Fort Collins flood.
STORM TRACKING ANALYSIS
The following image shows the results of an analysis of
the motion of the Fort Collins thunderstorm of 28 July, 1997, based on
Cheyenne, Wyoming WSR-88D observations ( Landel et
al. 1998). This analysis is overlaid on a digital terrain model.
The highest terrain is yellow, while the lowest terrain is magenta.
The boundary of Spring Creek watershed is outlined in black.
The jagged red line shows the track of the centroid of
the storm over time (all times UTC), the location of the centroid at different
times is denoted by red arrows. The four colored ellipses show the
approximate extent of the storm at four different times. From this
analysis, it is clear that the rising terrain of the front range of the
Rocky Mountains played a very significant role in the motion (temporal
evolution) of this storm. Note: all times are UTC (MDT+6 hours).
NATIONAL RADAR SUMMARIES
Select a date/time from the table below to view WSI
Intellicast qualitative national radar summaries (all times UTC).
Notice that there is almost continuous extreme rainfall in northeastern
Colorado over this time frame. The Fort Collins storm does not stand
out in these images because of its' small scale. (Images generated
by WSI).
ANIMATED NATIONAL RADAR SUMMARIES
Select one of the following three animations which cover
different time periods. These animations clearly illustrate the heavy
widespread precipitation in northeastern Colorado during the same time-frame
as the Fort Collins flood. (all times UTC). (Images generated
by WSI).
VISUAL AND INFRARED SATELLITE IMAGERY
Select the following links to view satellite imagery.
(These images are LARGE)
SURFACE SYNOPSIS
Click here to
view the surface conditions at the time of the Fort Collins flood (0100
UTC 29 July 1997 or 7:00 p.m. MDT 28 July 1997). Notice that the
temperature/dew point spread in Denver is only 1 degree F, with a dew point
of 63 degrees. This indicates a near-saturated airmass at the surface-
a very unusual condition for late July in Colorado.
OTHER WEB-AVAILABLE QUALITATIVE DATA
An animation of
Cheyenne, Wyoming, WSR-88D (CYS) Radar Reflectivities
(1800-2215 MDT animation), produced by CSU Atmospheric Science Dept. shows the persistence of rain over Fort
Collins. The grid on the animation are the major streets in Fort Collins. The bold line shows the location of Spring Creek.
