This is the Marion County Amateur Radio SKYWARN home page. Marion County Amateur Radio SKYWARN operates under the call sign WA9MC courtesy of the Marion County Amateur Radio Society.
What is Skywarn? Skywarn is a volunteer program developed in the late 1960's with over 290,000 trained severe weather spotters. These volunteers help keep their local communities safe by providing timely and accurate reports of severe weather to the National Weather Service.
- In the average year the United States sees:
- 10,000 severe thunderstorms
- 5,000 floods
- 1,000 tornadoes
- Dozens of Hurricanes
Who is Eligible? NWS encourages anyone with an interest in public service and access to communication, such HAM radio, to join the SKYWARN® program. Volunteers include police and fire personnel, dispatchers, EMS workers, public utility workers and other concerned private citizens. Individuals affiliated with hospitals, schools, churches, nursing homes or who have a responsibility for protecting others are also encouraged to become a spotter.
Training opportunities around the state can be found at http://www.weather.gov/ind/spotter_talks
Online Training: https://www.meted.ucar.edu
Additional Information: Become a Storm Spotter from Home (Article with multiple resources)
In Marion County we will link the 146.760 (primary) and 443.250 (secondary/backup) repeaters during a net.
How To Participate
Generally we will start a net when called upon by NWS and Central Indiana Skywarn when weather looks to become severe, however there are times were we might call up a net in advance or for active monitoring of weather or situation.
It is strongly recommended that participating hams have some weather training and understand net etiquette. However, all are welcome to check in and provide information as requested by Net Control.
Spotter and Net Resources
What Makes Weather Severe?
This can be sometimes subjective but NWS says:
- Hail 1" or larger and/or
- Wind gusts 58 mph or greater or
Tornado: A violently rotating column of air extending from a thunderstorm cloud to the ground. The Enhanced Fujita Tornado Intensity Scale is used to categorize tornadoes
Funnel Cloud: A condensation funnel extending from the base of a towering cumulus or cumulonimbus, associated with a rotating column of air that is not in contact with the ground (and hence different from a tornado). A condensation funnel is a tornado, not a funnel cloud, if either a) it is in contact with the ground or b) a debris cloud or dust whirl is visible beneath it.
What kind of damage did the wind cause?
- Small limbs down (less than 2" in diameter)
- Large limbs/branches down (more than 2" in diameter)
- Trees snapped or uprooted
- Power lines down
- Structural damage and/or Roof damage
What size hail did you see?
- Pea Size: 0.25 inches
- Small Marble: 0.50 inches
- Penny: 0.75 inches
- Nickel: 0.88 inches
Any hail size at or above a Quarter (1.00 inches) is severe thunderstorm criteria:
- Quarter: 1.00 inches
- Half Dollar: 1.25 inches
- Ping Pong Ball: 1.50
- Golf Ball: 1.75 inches
- Hen Egg: 2.00 inches
- Tennis Ball: 2.50 inches
- Baseball: 2.75 inches
- Grapefruit: 4.00 inches
- Softball: 4.50 inches
What kind of flooding was observed?
- Minor street flooding
- Low water crossings flooded
- Widespread flooding
- Home/Business flooded
- Creek/Stream out of banks
- River out of banks
- How much rain fell, e.g. 1.50".
- What period of time did the rain fall? (e.g. 1 hour 15 minutes.)
- Was the rainfall measurement estimated or measured with equipment?
- How much snow fell (to nearest tenth of an inch if possible), e.g. 3.5".
- What period of time did the snow fall? (e.g. 1 hour 15 minutes.)
- Was the snowfall measurement estimated or measured?
- How much icing was observed (to nearest tenth of an inch if possible), e.g. 0.5".
- What period of time did the ice accumulate? (e.g. 2 hours 30 minutes.)
- Was the rainfall measurement estimated or measured?
We are generally interested in wind speeds of 40-50 mph or higher. Here is some info on how to estimate wind speeds:
39-54 mph: Twigs break off trees; wind generally impedes progress.
55-72 mph: Damage to chimneys and TV antennas; pushes over shallow rooted trees.
73-112 mph: Peels surfaces off roofs; windows broken; light mobile homes pushed or overturned; moving cars pushed off road.
We are mainly interested in visibility reports of a half mile or less.
Indy area hams know that during regular conditions the KM9E 443.250 and 442.650 repeaters are linked. This changes during a weather event:
- Central Indiana Skywarn brings up links:
CIS will disconnect the 443.250 from the 442.650 in order to then link the 442.650 with the other Central Indiana repeater and simplex links.
- 443.250 will stand alone until..Marion County brings up a net
- When Marion County brings up a net, Net Control will connect the 443.250 to the 146.760 repeater.
- This all reverses as the nets close down.
On the first Friday of each month, Marion County does a test of the siren system at 11:00 A.M. Marion County ARES and Marion County Amateur Radio Severe Weather groups run a 'Siren Check Net'
on the 146.700MHz repeater to gather siren information from participating stations. This information is forwarded to the Marion County EOC by way of a local RACES officer.
Siren Check Net
- On the first Friday of the month...
- 10:50 AM Net Control starts the net and takes early check in's
- 11:00 AM (approx) net pauses, sirens sound
- 11:02 AM (approx) Net Control goes through check in list:
- Calls each station and asks
- Did you hear the siren
- Did the siren have rotation (visual or inferred)
- Location (actual or approximate)
- Additional check-in's with or without reports will be taken.
Marion County Amateur Radio Society (WA9MC) in cooperation with Marion County ARES are the net managers for Marion County Amateur Radio Severe Weather Nets and Amateur Radio Skywarn. Questions or comments should be sent to IndySkwyarn at gmail.com or mcinares at gmail.com 73