nctcog logo
 
Emergency Preparedness
navigation bar
 

Collaborative Adaptive Sensing of the Atmosphere (CASA WX)
Frequently Asked Questions and Updates

PRODUCT AND NETWORK UPDATES

Posted April 7, 2017
Radar loop reduced to 20 minutes. The playback feature, accessed by clicking the Play button in the lower navigation bar, now replays approximately the last 20 minutes of radar data. This change impacts the Reflectivity+Winds product on the DFW Network Page and all the CASA radar products on the individual radar pages.

Nowcast product taken offline. The Nowcast product has been taken offline for improvements.

NWS warning expiry fixed.  Polygons showing the NWS warnings will now automatically disappear shortly after the warning expires.  .

NEW FEATURES IN CASA WX WEBSITE

Posted April 7, 2017
Easily access archived CASA data. You can now easily access archived CASA data directly from the CASA WX website. The archive starts April 1, 2016 and is current to the latest time. Data may be unavailable if the radar network or an individual radar was offline during the requested period.  Navigation: Click on the gray clock button next to the Product menu on the top left corner of the website. This will pull up  ‘start hour’ and ‘end hour’ pull down menus (in the user’s local time).  The format is YYYY:MM:DD:HH. Select the start and end hour of interest and click the green arrow ‘Download’ button. The website will now display data starting at the start hour selected.  Use the Play, Prev, Next buttons to move through the archived data set. Click on the circular arrow Refresh button in the bottom Navigation bar to return to current data. You can hide the start and end time pulldowns by clicking again on the gray clock button. 

Toggle between NEXRAD and CASA data.   To make it easier to compare NEXRAD and CASA data, there’s a new toggle button on the bottom navigation bar of the individual radar pages.  If you are looking at single radar CASA data, the radar image diminishes if there is very hard rain or hail right over the radar.   So, we recommend that you toggle back and forth between NEXRAD and CASA to maintain your situational awareness.    Note, this functionality does not currently work when looking at data retrieved from the archive interface described above, however archived Nexrad images can be viewed by selecting the Nexrad product in the dropdown menu and using the archive normally.

Multiple radar tilts.  Radars scan at multiple levels called tilts so they can observe the storm at different heights.  The radar beam spreads like a flash light beam, the beam gets higher and higher as it get further way from the radar. For most CASA users, looking at the 2 degree tilt will give you good information.  If you want to know what is happening closest to ground level, then use the 1 degree tilt, where available.  Also, note that you can right click the radar image to see how high the beam is from the ground. 

New Rainfall Accumulation products. CASA radars use dual polarization technology and this enables the accurate measurement of rainfall. CASA rain products are generated by combining the measurements from the higher frequency X-band radars with the lower frequency S-band radar (NEXRAD). Resulting rainfall measurements are accumulated over various time periods to support different phases of flood response. The following new rainfall accumulation products have been added:

  • 24 hr Accumulation. This product shows the rainfall accumulation over the last 24 hours. The product is updated every hour, on the hour.
  • 48 hr Accumulation. This product shows the rainfall accumulation over the last 48 hours. The product is updated every hour, on the hour.
  • Max 15min Accumulation. This product depicts the maximum rainfall accumulation over any 15 minute interval during the last hour. The product updates every minute. This product helps stormwater managers determine locations where flash flooding is most likely to occur.

Note that Accumulation products only measure the amount of rainfall that has fallen on the ground in a given location over a set time interval. It should not be interpreted as water depth level on the ground. Actual water depth or flooding depends on several other factors such as soil conditions, slope and drainage.

FREQUENTLY ASKED QUESTIONS

How do I know if the CASA WX radar network is up and running?

The CASA WX site displays real time products from the CASA radar network.  Currently seven radars are operational.  The radars are turned on in advance of when precipitation is expected or possible and may be turned off when dry weather is expected for several consecutive days.   National Weather Service forecasts and discussions are used in conjunction with those of the Storm Prediction Center and judgment of the radar operations team to make this determination.  .  This approach saves on the wear and tear of the radars. Occasionally the radars are turned on during clear weather to support important community events, as requested, to provide coverage in case of sudden storm initiation. There is a red circle-shaped button at the bottom of the screen in the lower navigation bar, which turns green when the network is turned on. There is a similar button to indicate the status of individual radars on their respective pages.

How often do CASA WX website products update?

Single radar products update every one to two minutes. The website is set to ‘auto-refresh’ every 30 seconds with the latest data. You can also click on the manual fresh button in the lower navigation bar to ensure that you are looking at the latest available data. Note that when the website is first accessed, it might take a short time to load.

Network level products auto-refresh when network level processing and analysis is complete. Update times for network level products vary from product to product. Note that when the website is first accessed, it might take a short time to upload.  If the user is looping the data via the play button, or has manually navigated via the next or prev buttons, auto-refresh functionality will cease.  Click the circular refresh button, or refresh the browser to return to auto-refresh mode.

How do I interpret the Winds data?

Wind arrows show the direction of the wind.  This product is great for keeping track of winds in real time as they impact your jurisdiction.  This product updates each minute.  Wind is measured at 5,000 ft and below. Important:   If you don’t see arrows, winds may still exist because 1) the radars can only measure wind where there is precipitation (rain, hail, sleet, snow) or other  “scatterers” (dust, debris) and 2) this wind product requires overlapping radar coverage where the radar beams cross at certain angles and at certain heights.  In addition, around the airport and skyscrapers some spurious winds may be reported by the radar. Navigation:  Toggle the Winds button on the bottom to see the winds.  This product is best seen at a zoomed in view.  Each time you zoom in, toggle the wind button and you will see finer scale wind arrows. You can go back and forth in time, but each time you have to toggle the winds button to replot the winds.  Winds will update if the page is auto-refreshing.

 

CASA WX Executive Council Leadership:
Amanda Everly - City of Fort Worth
Joe Frizzell - City of Midlothian

For more information contact Molly McFadden

 
 CONTACT US | SITE MAP | LEGAL | SYSTEM REQUIREMENTS
 North Central Texas Council of Governments | 616 Six Flags Drive P.O. Box 5888 Arlington, TX 76005-5888
 Main Operator: (817) 640-3300 | Fax: (817) 640-7806