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Refer to Exhibit 2.1.6.8-1 for a display of this menu.

Exhibit 2.1.6.8-1. The Upper Air Menu

The Upper Air Menu provides access to upper air plots, aircraft and rawinsonde data, along with profiler data. For user ease, frequently used products are available in the pull-down menu, while less frequently used products are contained in cascading menus. Profiler This portion of the Upper Air Menu for RSA contains selectors for the 50 and 915 MHz Profilers and the mini sodars - both in time-height and perspective layouts. In addition, you can access the National Profiler Network data in time-height, plan view plots at mandatory levels, and in perspective layout. Aircraft The Aircraft data include Low-, Mid-, and High-level PIREP, Icing and Turbulence plots. MDCRS data include plan-view plots for various 5kft layers and ascent/descent soundings. Using the availability plots (in the Surface Menu under the Model-based Displays submenu) and the ACARS map background, you can locate airports that have available soundings. RAOB Radiosonde Observations (RAOB) data are plotted on the standard skew-T/log p thermodynamic diagram and can be sampled by pressing and holding Mouse Button 1 over the chart. A small "dynamic" reference map indicating the location(s) of the plotted sounding(s) is provided in the upper-left corner of the Large Display. If you overlay another skew-T whose location is far from the original sounding location, the reference map may not include this new location. To "refresh" the reference map, simply zoom in once over the reference map with Mouse Button 2 and then zoom back out with Mouse Button 1. A new reference map will be generated to include all the sounding locations. The Interactive Skew-T Program plots and derives quantities on a skew-T/log p diagram and on a hodograph. You can edit the skew-T and hodograph data and obtain instantaneous information on the modified data. For the Interactive Skew-T application, lifting options are available through the user interface. Refer to Section 6.1 Interactive Skew-T for further details.

Skew-T Parameters

Also plotted on the standard skew-T/log p thermodynamic diagram is the lifted parcel trajectory, displayed on zoom factors greater than 1. For a 12Z sounding, the parcel trajectory is computed based on a surface parcel temperature represented by the forecast maximum temperature for that sounding. At all other observation times, the surface parcel temperature is represented by an average temperature and dewpoint through the lowest 50 mb of the sounding. For the 00Z soundings, the temperature and dewpoint are represented as a low-level (50 mb) mean. For the 12Z soundings, the forecast maximum temperature is used as the "modified" parcel temperature, with the surface dewpoint temperature as the parcel dewpoint. The parameters affected by these modified values are noted with asterisks in the second column of the parameters list on the sounding plot.

The MDPI (Microburst-Day Potential Index) and the Windex (Wind Index) determine whether the environment is favorable for microburst development. The MDPI utilizes vertical profiles of environmental equivalent potential temperature, while the WINDEX predicts the maximum expected gust possible for a given environmental sounding. For a full description of these equations and the optimal index values, refer to http://www.wdtb.noaa.gov/workshop/psdp/Roeder/sec2.htm

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