PCARA
POLK COUNTY AMATEUR RADIO ASSOCIATION
PCARA

Weather Spotting

Click HERE for a map of
Polk County, Wisconsin

Skywarn
REPORTABLE CONDITIONS CRITERIA

URGENT PRIORITY
TORNADO Visible debris cloud or; Funnel in contact with the ground or; Funnel more than half-way to ground from cloud base: Report Immediately! (Break in if necessary)

FUNNEL CLOUD Report Immediately!

ROTATING WALL CLOUD
Wall cloud with obvious, sustained rotation, rising motion
Observe 1 - 3 minutes, and report if still rotating

HIGH PRIORITY
NON-ROTATING WALL CLOUD
Wall cloud without rotation. Confirm rising motion; Observe 5 - 10 minutes, and report if still present

WIND DAMAGE Large branches off trees (3" dia); trees uprooted; significant
damage to well-built structures; billboards, large road signs damaged, knocked down

HAIL Report any sized hail; amount, and maximum size
Estimates: measure when possible, 3/4" and larger is severe
"pea-sized" - 1/4 inch "golf ball-sized" - ~ 1½ inch
"dime-sized" - ~3/4 inch "tennis ball size" - ~ 2 inch
"quarter-sized" - ~ 1 inch

SIGNIFICANT FLOODING
Report large amounts of moving water which poses a threat to life or property; ponding (standing water in intersections, etc.) is not usually reportable

AS REQUESTED BY NET CONTROL
ANY CONDITION(S) ASKED FOR BY NET CONTROL
Report conditions observed from your area, including conditions not normally reportable if asked for by the Net control operator.

The PCARA activates a SKYWARN net when severe weather approaches our area. Spotter reports are relayed to the National Weather Service.
The National Weather Service, K0MPX published a set of "Amateur Radio Operating Procedures" for use during emergencies.
KC9PJJ_WD9GWG
Mark KC9PJJ (left) and Chuck WD9GWG (right) review the Polk County "Clear View Site" map. The Westerly view behind them is from point #13 near Dresser. In August of 2003, Chuck WD9GWG and Bud KB9ZAZ (sk) searched the county for sites which met "clear view" criteria. 17 spots were identified as being able to see a distance of 4 to 7 miles or greater. Northwest Wisconsin generally receives severe weather from the West and Southwest.

Reporting Severe Weather
Spotters provide an invaluable service to their communities and to the National Weather Service. Spotter reports help your community by assisting local public safety officials in making critical decisions to protect lives - when to sound sirens, activate safety plans, etc.
Spotter reports also help the NWS in the warning process. Your report becomes part of the warning decision making process, and is combined with radar data and other information and used by NWS forecasters to decide whether or not to:
a.. Issue a new warning
b.. Cancel an existing warning
c.. Continue a warning
d.. Issue a warning for the next county
e.. Change the warning type (from severe thunderstorm to tornado, for example)
For your reports to be the most useful, they should be as detailed, accurate and timely as possible.  Use the guidelines below to help you make your report:

The Importance of Coordination
Spotter networks usually work best when a central location (an EOC or warning point, for example) collects reports from the local spotter network, then relays a consolidated report to the National Weather Service. This reduces duplicate reports and makes the system flow smoothly.
In this type of network, communication between the spotter and the control point must be clear to avoid misinterpretation. As a report is relayed through multiple sources, the chances for error being introduced into the chain grow.

Look at this example:
ORIGINAL SPOTTER REPORT at 730 PM:
"I am 3 miles north of Mayberry on Highway 78. I see a tornado about 5 miles to my northwest. It looks to be moving east along Highway 412"
Spotter report is relayed to another station, who relays it to the county warning point, who relays it to the NWS.
REPORT AS RECEIVED BY NWS at 740 PM:
"There is a tornado in Mayberry"
Obviously, the report the NWS received is not accurate - the location and the time are incorrect.

WHAT TO REPORT
Weather Events
Although reporting criteria may vary slightly depending on the spotter network and local needs, these are the events the National Weather Service would like to know about as soon as possible:
TORNADO
FUNNEL CLOUD     Organized, persistent, sustained rotation
WALL CLOUD     Organized, persistent, sustained rotation
HAIL  Dime size or larger Report the largest size hailstone
WIND GUSTS 58 mph or higher Specify estimate or measurement
FLOODING     Flooding that impacts roads, homes or businesses.
STORM DAMAGE     Damage to structures (roof, siding, windows, etc.) Damage to vehicles (from hail or wind). Trees or large limbs down. Power/telephone poles or lines down. Damage to farm equipment, machinery, etc.
Again, reports should provide as much detail as possible to describe the where, when, how, etc of the event.

Some commonly used hail sizes
Pea  .25 inch  Golf Ball  1.75 inch
Half-inch  .50 inch  Hen Egg  2.00 inch
Dime  .75 inch  Tennis Ball  2.50 inch
Nickel  .88 inch  Baseball  2.75 inch
Quarter  1.00 inch  Tea Cup  3.00 inch
Half Dollar  1.25 inch  Grapefruit  4.00 inch
Ping Pong Ball  1.50 inch  Softball  4.50 inch

General Guidelines for Estimating Wind Speeds
30-44 mph (26-39 kt)  Whole trees in motion. Inconvenient walking into the wind. Light-weight loose objects (e.g., lawn furniture) tossed or toppled.
45-57 mph (39-49 kt)  Large trees bend; twigs, small limbs break and a few larger dead or weak branches may break. Old/weak structures (e.g., sheds, barns) may sustain minor damage (roof, doors). Buildings partially under construction may be damaged. A few loose shingles removed from houses.
58-74 mph (50-64 kt) Large limbs break; shallow rooted trees pushed over. Semi-trucks overturned. More significant damage to old/weak structures. Shingles, awnings removed from houses; damage to chimneys and antennas.
75-89 mph (65-77 kt)  Widespread damage to trees with large limbs down or trees broken/uprooted. Mobile homes may be pushed off foundation or overturned. Roof may be partially peeled off industrial/commercial/ warehouse buildings. Some minor roof damage to homes. Weak structures (e.g., farm buildings, airplane hangars) may be severely damaged.
90+ mph (78+ kt)  Many large trees broken and uprooted. Mobile homes damaged. Roofs partially peeled off homes and buildings. Moving automobiles pushed off the road. Barns, sheds demolished.

HOW TO REPORT
Your severe weather report should be detailed but concise, and should address the following questions:
WHAT did you see?
WHERE did you see it?   Report the location/approximate location of the event. Be sure to distinguish clearly between where you are and where the event is thought to be happening ("I'm 5 miles north of Mayberry. The tornado looks to be about 5 miles to my northwest").
WHEN did you see it?   Be sure that reports that are relayed through multiple sources carry the time of the event, NOT the report time.
Any other details that are important - How long did it last?
Direction of travel? Was there damage? etc.

SKYWARN
SPOTTERS
Net Control
Chris KC9NVV
Fred
AB9LV
Marv
KC9IRT
Chuck
WD9GWG
Greg
N9CHA
Duana
KC9UVK
Tom
KC9UWA
Diana
KC9SLN
Len
KC9TPV
Josh
AG9K
Mike
KK9MC
Bill
K9WEN
Kathy
Polk OEM
Rick
W9WS
Joe
KB3WYL
Mark
W9GWG
Bill
WY9E
Mark
WM9E
Ona
KE5QMJ
Mel
KF6OZ
Steve
KC9WKY

N9XH - Polk County Amateur Radio Association - 1732 Forest Circle - Balsam Lake - WI - 54810 - Info@N9XH.org