D2D Surface Observations
Surface Displays
The Obs menu contains a number of surface observations and warning overlays that involve a mixture of national datasets brought in through the Satellite Broadcast Network (SBN) and local datasets brought in through the Local Data Acquisition and Dissemination (LDAD). In RAC, surface observations are particularly important in monitoring changes in the near-storm environment, so we will highlight some of the important characteristics of surface observations.
The Surface Plot, METAR Station Plots, and Maritime observations are primary ways of loading national hourly surface observations with wind barbs, temperature, dewpoint, pressure, visibility, and precip type icons that can be sampled for more detail. The Other Plots menu allows you to plot other METAR fields like 1hr and 24hr precip, or change the frequency to 15 minutes to be able to view sub-hourly changes. One important thing to understand about surface observations are that the density of plotted observations is a function of zoom level to make the displays readable. The progressive inclusion of more observations as you zoom in is called progressive disclosure in AWIPS. With surface observations you always need to zoom in to see all the data if you are on the default density settings.
If your CWA has Mesonet observations, they will be listed under Local data, and you can select a higher temporal resolution from 1 min, to 5 min, to 30 min. Mesonet sampling is different from METAR and varies somewhat between Mesonet networks.
Another important data type that can be brought in through LDAD is the Meteorological Phenomena Identification Near the Ground (mPING) observations which are a high temporal resolution national crowd-sourced public surface reporting system for things like precipitation type, flood, mudslides, and tornado reports. As with surface observations you need to zoom in to see all the data. Also, sampling the report icon will inform you of what the report is and supplemental data.
The Local Storm Reports released by the NWS are also displayable from the Obs menu along with Lightning data.
There are multiple lightning datasets that are available at different sites in AWIPS. There are cloud-to-ground stroke discharges, inter-cloud pulse discharges, and flash discharges consisting of closely associated inter-cloud pulses and/or cloud-to-ground strokes. The AWIPS menus have entries for:
NLDN: Vaisala's National Lightning Detection Network (cloud to ground flash +/- polarity display over the continental U.S. (CONUS) and a small portion for Outside the Continental U.S. (OCONUS))
GLD: Global Lightning Dataset (cloud to ground stroke +/- polarity display over the globe) from NLDN CONUS and GLD360 OCONUS (note: see the Adding Display Options to AWIPS for Vailsala Merged Lightning Total Lightning Google Doc for instructions on integrating IC pulses from NLDN/GLD360 into this data)
ENI Total Lightning: Earth Network's intra-cloud flash, cloud-to-ground flash +/- polarity, and total lightning pulse over the CONUS and OCONUS sites
GLM: Geostationary Lightning Mapper (total lightning with no CG/IC discrimination over CONUS and OCONUS up to 52 deg N latitude)
LMA: Lightning Mapping Array (total lightning display for small networks across the CONUS)
Ground-based lightning data (excluding LMAs) is displayed as point data with +/- symbols to represent polarity. The number of lightning points visible in the editor is displayed in the upper-left part of the editor, so the user can manipulate the zoom level to see the number of points plotted over the domain in the CAVE editor. Lightning data can also be displayed as a gridded density product where the number of flashes, strokes, or pulses over a gridbox are calculated. Lightning trends, particularly with total lightning data, can be related to storm intensification trends and severe weather. Gridded density trends can be facilitated using the AWIPS Tracking Meteogram tool (see D2D Tools section).
There are three applications in the Obs menu that slice and dice the surface observations in a table format for monitoring maritime, fog, and snow conditions:
SAFESEAS - System on AWIPS for Forecasting and Evaluation of Seas and Lakes
Fog Monitor - Algorithm suite applied to surface observations and satellite data to identify potential ares of fog
SNOW - System for the Nowcasting of Winter Weather
These decision assistance allow you set to set up thresholds that are highlighted in different colors in the table and that also have a monitoring status icon on the AlertViz toolbar that can change colors depending on user configuration. These tools are not frequently used, but may be of use to some offices.
In addition to standard surface observations, the warning hazards are displayable from the Obs menu.