So with all of the historic weather we’ve had here with the remnant low of Hurricane Ida causing 7 tornadoes and severe flooding, I figure that I would share and highlight some of the most important to know weather related information available on the ARES/RACES of Delaware County website.

Weather Information & Links

Here you’ll find general weather information, links to helpful websites and apps, as well as training that may be helpful.


  • National Weather Service Radar official and newly revamped NWS site to show raw radar data in near real-time.
  • USGS Water Dashboard this newly revamped dashboard can be extremely helpful in identifying or confirming flooding conditions when they occur.
  • USGS Steamflow Data links to sensor sites in this area.
  • Weather Underground provides the world's most accurate hyper-local weather forecasts in addition to an interactive weather radar, satellite maps and severe weather alerts. Powered by our unique community of weather enthusiasts reporting live data from over 270,000 personal weather stations, this crowd-sourced data generates accurate forecasts targeted to your precise location.
  • WunderMap Weather Underground’s WunderMap provides interactive weather and radar Maps for weather conditions for locations worldwide. By selecting a station nearest to your location, you can see real-time data points such as temperature, pressure, wind speed and gusts, along with much more.


  • Weather Underground provides mobile apps for Android and iOS devices.
  • RadarScope provides Windows and mobile apps on Android and iOS devices. RadarScope is a specialized display utility for weather enthusiasts and meteorologists that allows you view NEXRAD Level 3 and Super-Resolution radar data along with Tornado, Severe Thunderstorm, Flash Flood and Special Marine Warnings, and predicted storm tracks issued by the U.S. National Weather Service. It can display the latest reflectivity, velocity, dual-polarization, and other products from any NEXRAD or TDWR radar site in the United States, Guam, Puerto Rico, Korea, and Okinawa, as well as data from Environment Canada and Australian Bureau of Meteorology radars. These aren't smoothed PNG or GIF images, this is native radar data rendered in its original radial format for a high level of detail.




  • Beaufort Scale The Beaufort scale is an empirical measure that correlates wind speed to observed conditions at sea or on land.
  • Enhanced Fujita Scale The Enhanced Fujita scale, an updated version of the original Fujita scale that was developed by Ted Fujita with Allen Pearson, assigns a numerical rating from EF0 to EF5 to rate the damage intensity of tornadoes.
  • Saffir-Simpson Hurricane Wind Scale The Saffir–Simpson hurricane wind scale, assigns a numerical classification of hurricanes into five categories distinguished by the intensities of their sustained winds.
  • Wind Alert Terms and Signal

How to Locate Tornado on Radar

Tornado Debris Signature

  1. Base Reflectivity - Reflectivity will indicate a severe thunderstorm, but a hook echo may not always be present.  Typical returned values will be 45 dBZ and greater. Super resolution return averages may have a higher dBZ value.

  2. Storm Relative Velocity - An azimuthal couplet should be present with strong gate-to-gate sheer indicated on SRV.

  3. Differential Reflectivity - The region co-located with the rotational couplet should have very low or near zero ZDR present, indicating lofted objects might be tumbling.

  4. Correlation Coefficient - The region co-located with Relectivity values over 45 dBZ and the rotational couplet should have considerably lowered CC values, typically below 0.80.  This TDS area may have higher surrounding CC values indicating differing sized debris.

WSR-88D Tornado Debris Signature (TDS) Quick Reference

Tornado Intensity Guidance

Example Radar Image

SKYWARN Spotter Weather Training

SKYWARN is a self-contained network of certified weather spotters sponsored and trained by the National Weather Service (NWS).  Many spotters are Amateur Radio operators who submit observations via radio. Compiled observations are forwarded to meteorologists at local NWS offices and the data is incorporated into reports and forecasts.  SKYWARN volunteers collect on-the-spot weather observations in localized areas that assist NWS meteorologists in producing forecasts that are more accurate and warnings that are more timely.

Online SKYWARN Training Options

You only need to complete one of the Basic courses listed to become a spotter:

  1. SKYWARN Basic Spotter Training 2019 Videos - Mt. Holly NJ - Recorded local SKYWARN Basic Spotter presentation from the Mt Holly, NJ NWS office.  View a series of 3 YouTube videos recorded at the end of 2019 (the Skywarn presentation has changed very little since then).

  2. SKYWARN Basic Spotter Training 2021 Videos - Central PA - Recorded local SKYWARN Basic Spotter presentation from the Central PA NWS office.  View their video from 2021.

  3. SKYWARN Basic Spotter Training - MetEd - Online course  few notes about this option: this doesn't have some of the local-specific information, but it is a great course. Also, you may have to register to take any module on this site, but it is free.

The local NWS offices would occasionally hold these course in-person, however most options are all online for now.

SKYWARN Spotter Registration for Mt. Holly Office - in order to register your information and obtain your Spotter ID.  You can always report weather to your local NWS office, but reports from spotters and local emergency management agencies are always considered to be more accurate.

Once you get your Spotter ID, you can also add to your knowledge with the advanced spotter course.  If you have ever wondered how to spot a tornado on weather radar using both reflectivity and velocity returns, this is for you.

  1. SKYWARN Advanced Spotter Training 2020 Videos - Central PA - Recorded local SKYWARN Advanced Spotter presentation from the Central PA NWS office.  View their video from 2020.

FEMA Weather Awareness Courses

These weather awareness courses go more in depth into specific weather threats and are extremely helpful.

These are offer through FEMA and there is no charge to signup and attend.  They are held both in person and online via video conference.

Easiest way to find these classes is on the FEMA First Responder Training schedule:

One of my favorite providers for online offering has been the National Disaster Preparedness Training Center (NDPTC):