The primary role of the nowcast environment is to collect weather data, execute algorithms for producing a combined thunderstorm forecast, and provide a graphical display tool for viewing the various datasets.

Thunderstorm Auto Nowcasting System

Data incorporated into the nowcast environment includes WSR-88D (NEXRAD) radar, satellite, sounding, and surface data.

The software applications in the nowcast environment include algorithms for identifying and tracking thunderstorm movement, identifying boundaries, wind retrieval from radar, as well as a fuzzy-logic engine which allows the user to combine the weighted outputs from the various algorithms to produce a single, combined forcast. Subsequent verification of generated forcasts are available both visually and statistically.

In realtime operations the nowcast environment initiates and maintains process control through an auto-restart mechanism. The auto-restarter provides the user with an automated, hands-free forecasting environment.

Many components of the nowcast environment also can be operated in archive mode. Archive mode allows the user to re-run algorithms with newly specified parameters and to view historical datasets.

The key hardware components of the Auto-Nowcast Environment are:

• A collection of UNIX workstations on a local area network
• A mechanism for archiving data

The key software components of the Auto-Nowcast Environment are:

• Data ingest
• Data distribution
• Process control mechanism
• Analysis algorithms
• Graphical data displays

The key data components of the Auto-Nowcast Environment are:

• Doppler radar data
• Sounding data
• Surface data
• Satellite data

Other features include:

• System monitor

Logging onto the Auto–Nowcast Machines

Because the Auto–Nowcast Environment involves many complex algorithms, the power of many machines or hosts are combined to make up the entire environment. All machines in the Auto–Nowcast Environment are set up to operate under the "nowcast" user login. See your site administrator for the password for this login. Some of the Auto–Nowcast Environment machines are configured with auto–login at boot–up some are not, depending of the needs of the particular machine and the local area network configuration at the site. In an auto–login setup, booting the machine will automatically result in a login session as user "nowcast" and an will initiate an X–windows session. On machines which are not configured for auto–login at boot–up, the user must manually login as user "nowcast" and start X–windows using the following commands:

Once the X–windows session is started (either manually or via auto–login) the user will see a console window for system messages, an xterm for running UNIX commands, and a window manager tool bar. (look on reflect...)

Starting up the Auto–Nowcast Environment

The Auto–Nowcast Environment can be managed by any host through command line program execution; however, an X interface with pull–down menus is available on the control host. The control host can be determined by typing the command:

echo $CONTROL_HOST

The realtime Auto–Nowcast Environment is started from the control host either by typing the command:

niwot_startup

or via a pulldown menu on the $CONTROL_HOST:

It only takes a few minutes for all of the Auto–Nowcast Environment process to start up. Several graphical windows will appear on the control host at startup. Each of these windows and their role in the Auto–Nowcast Environment will be discussed in detail below. Because each of the algorithms within the Auto–Nowcast Environment requires different amounts of input data for their processing, the results of the algorithms will not begin to arrive until the Auto–Nowcast Environment has been up and running for a while. Some algorithms will produce data within six minutes, others will not produce data until there is significant weather.

Shutting Down the Auto–Nowcast Environment

The realtime Auto–Nowcast Environment is shutdown from any host by typing the command:

niwot_shutdown

or via a window pulldown menu on the $CONTROL_HOST: