![]() The Operational Significant Event Imagery website includes photos of hurricanes, volcanoes, forest fires, floods and dust storms. Here's a site where you can find amazing photographs taken from space of significant events around the world. Pretty much everything you want to know about tropical weather, including hurricanes threatening the South Texas coastline, can be found here. This is the official website of the National Hurricane Center/Tropical Prediction Center. Here you'll find the latest Rio Grande River flow conditions, updated daily. The International Boundary and Water Commission reports the latest information on the levels of Falcon and Amistad Reservoirs on this website. This is especially helpful at night when ground spotters are unable to see the tornado.The National Weather Service in Brownsville maintains this excellent website containing links to radar and satellite images, computer forecasts, hydrology, climatology, aviation forecasts and more. The "dual-pol" upgrade included new software and a hardware attachment to the radar dish that provides a much more informative two-dimensional picture.ĭual-pol radar helps NWS forecasters clearly identify rain, hail, snow, the rain/snow line, and ice pellets improving forecasts for all types of weather.Īnother important benefit is dual-pol more clearly detects airborne tornado debris (the debris ball) - allowing forecasters to confirm a tornado is on the ground and causing damage so they can more confidently warn communities in its path. Take it to the MAX! Getting a Second Opinion Dual-PolarizationĪn addition to the NWS Doppler radar has been of dual-polarization of the radar pulse. Take it to the MAX! Volume Coverage Patterns: Turn it up! In precipitation mode, the radar completes a volume scan every 4-6 minutes depending upon which volume coverage pattern (VCP) is in operation, providing a 3-dimensional look at the atmosphere around the radar site. Once the radar sweeps through all elevation slices a volume scan is complete. These elevation slices comprise a volume coverage pattern (VCP). The NWS Doppler radar employs scanning strategies in which the antenna automatically raises to higher and higher preset angles, called elevation slices, as it rotates. The remaining 59 minutes and 53 seconds are spent listening for any returned signals. Ad-free plan users can upgrade to Plus to use the API. For Plus subscribers, access to the API is included in the package, simply activate the required API key in the account management. ![]() Therefore, the total time the radar is actually transmitting a signal (when the duration of transmission of all pulses, each hour, are added together), the radar is transmitting for a little over 7 seconds each hour. From now on you can access our observation data, analyses and forecasts automatically via our new weather API and use them for home automation, for example. By comparison, a typical home microwave oven will generate about 1,000 watts of energy. As the vehicle or train passes your location, the siren or whistle's pitch lowers as the object passes by.ĭoppler radar pulses have an average transmitted power of about 450,000 watts. You have probably heard this effect from an emergency vehicle or train. As an object moves away from your location, sound waves are stretched resulting in a lower frequency. With the "Doppler shift", the sound pitch of an object moving toward your location is higher due to compression (a change in the phase) of sound waves. The phase shift effect is similar to the "Doppler shift" observed with sound waves. Doppler radar sends the energy in pules and listens for any returned signal. A positive phase shift implies motion toward the radar and a negative shift indicates motion away from the radar. This then provides a velocity along the direction the radar is pointing, called radial velocity. When the WSR-88D transmits pulses of radio waves, the system keeps track of the phase (shape, position, and form) of those pulses.īy measuring the shift (or change) in phase between a transmitted pulse and a received echo, the target's movement directly toward or away from the radar is calculated. Doppler radarīy their design, Doppler radar systems can provide information regarding the movement of targets as well as their position. In addition, the time it takes for the beam of energy to be transmitted and returned to the radar also provides is with the distance to that object. That provides us with the ability to "see" rain drops in the atmosphere. The larger the object, the greater the amount of energy that is returned to the radar. ![]() As they strike objects in the atmosphere, the energy is scattered in all directions with some of the energy reflected directly back to the radar. The basics of radars is that a beam of energy, called radio waves, is emitted from an antenna.
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