The following WSR-88D Products must be included in the AWIPS RPS List
of each dedicated radar in order to run the full suite of SCAN 2.0 functionality
on each of those radars:
The SCAN Convective Threat Index (SCTI) is a numerical representation
of the severe weather occurring within a CWA. The SCTI button is located
directly below the WarnGen button on the D2D. The SCTI button has a severe
weather symbol on it. The button will be colored according to the following
criteria:
White
Little or no activity in the CWA
Green
General thunderstorms with low severe weather probabilities
in the CWA
Yellow
Thunderstorms with moderate severe weather probabilities
or a mesocyclone or TVS detected in the CWA
Red
Thunderstorms with high severe weather probabilities
and a mesocyclone and/or TVS detected in the CWA
Grey
Invalid index number, which means the SCAN processor
is not behaving properly.
If the mouse cursor is focused over this colored button, a small text
tip widget will appear, providing the maximum SCTI valueover the CWA and
what it represents. In addition to the SCTI button, the actual grid of
SCTI values over the CWA can be viewed via a D2D depictable, selectable
from the SCAN section of the radar menus. The following table can be used
to interpret the SCTI values:
100
Cell SWP >=70, MESO & TVS
90
Cell SWP >=70, MESO or TVS
80
Cell SWP >=70
70
30 <= Cell SWP < 70, MESO & TVS
60
30 <= Cell SWP < 70, MESO or TVS
50
30 <= Cell SWP < 70
40
Cell SWP < 30, MESO & TVS
30
Cell SWP < 30, MESO or TVS
10
CG LTG, High VIL, CZ
To make the SCTI values, we see which of the following "ingredients" are
present in a radar-centric field of 4x4 km grid boxes - VIL, 4-km CZ,
NLDN lightning, TVSs, MESOs, and our cell-based Severe Weather Probabilities
(SWPs). The non-gridded data - lightning, MESOs, TVSs, and SWPs - are
assigned to the nearest grid box. Depending on how many severe weather
indicators are present in each grid box (and in what combinations), the
box is assigned a SCTI value. It is important to keep in mind that these
numbers are not percentages; they are assigned threat values that model
the gamut between a garden variety thunderstorm and a rotating, tornadic
supercell. The numbers are not cumulative -- a grid box with CG lightning
and high VIL (for
a SCTI value of 10) that also has a MESO, TVS, and high SWP (a SCTI value
of 100) will not be assigned a a value of 110; instead, the maximum threat
found is the one that is used.
Editing the SCAN Site List and Use of Spotter Maps
Below are instructions on how to edit the site list for the SCAN thunderstorm
site detection function in AWIPS 4.1, i.e., the function that monitors
for the presence of a thunderstorm threat at a fixed geographic (point)
location. It might be useful to add the locations of fixed spotters to
this list in order to automatically monitor for the occurrence of thunderstorms
at these locations. The spotter map depictable could be used in conjunction
with the SCAN site threat depictable. This information is also being included
in the 4.2 D2D User's Guide.
To add a local site of interest (such as a local landmark or a spotter
location, for example) to the SCAN site field, perform the
following steps:
If the SCAN site threat depictable is loaded in the IGC screen, unload
the depictable.
Use an editor to open the file: /data/fxa/radar/XXXX/tstorm/sites.dat,
where "XXXX" is the
four-letter identifier of the dedicated radar.
At the bottom of the file add a new line. At the beginning of the
line, type a character string
(with a maximum size of 5 characters) as an identifier. Note that
any new sites should be
placed at the bottom of the file -- not in alphabetical order
in the list -- so as not to disrupt
the site ordering of previous SCAN runs in the inventory.
Skip at least 1 space and, on the same line as the identifier, add
the latitude of the new site
in decimal degrees format.
Skip at least 1 space and , on the same line as the identifier and
latitude, add the longitude
of the new site in decimal degrees format, using a negative value
to represent a point
west of the prime meridian.
Save the file.
To test the addition, wait at least 1 volume scan before displaying
the SCAN site
threat depictable. When the depictable is loaded, the new site should
be displayed
in the site field. If the site threat popup window is invoked, the
text message inside
will describe the conditions at the site.
Sites can also be removed from the "sites.dat" file by deleting the appropriate
line of site information. The file should contain no blank lines. Note
that this action may cause site threat data mismatches in the previously
inventoried site threat message files. It is therefore recommended that
this action only be taken in fair-weather conditions, when the inventoried
files are less likely to be displayed.
Using the "purgetime.txt" file
The editable "purgetime.txt" file in the $FXA_DATA/tstorm directory allows
the user to change the number of hours beyond which the purge function
will delete records in the SCAN Storm Cell database tables. For example,
if the file contains "5.0", when the purge function is called, it would
delete all records older than 5.0 hours for all tables (cells,
mesos, tvs's, and sites) in the "scandata" database.
Click on the link below to bring up a new window with the latest version
of the SCAN User's Guide. SCAN 2.0 User's Guide
SCAN 2.0 Screen Captures
Click on an image to see the full size image:
This figure includes the D2D, SCAN Storm Cell Table,
single trend, trend set, the
Attribute Color Threshold window, and the Alarm Information window.
It also
shows theSCTI button turned yellow (more
info on the SCTI button).
The Storm Cell Identification Display
(SCID) window.
This figure includes the D2D, SCAN Storm Cell Table,
Configurations menu,
Trend Set cascading menu, Edit/Create Trend
Set window, and a trend set example.
SCAN Data Monitoring System
This figure shows the Mesocyclone Table, the Storm
Cell Table with Vert
and Tips options on, and one pop-up tip.
National
Weather Service
Office of Science and Technology
Meteorological Development Laboratory
Last Modified:
April 14, 2004
Page Author: Iris Boon E-mail
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