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The
following is a list of weather event reporting criteria to help you
know what conditions should be reported to the Sherburne County
Skywarn Net Controller. Note that weather conditions must meet the
following criteria in order for the event to be reported
to the National Weather Service.
- Tornado or Funnel Cloud - Location,
time and direction of movement.
- Hail
- Pea-size or larger. NOTE: When
describing hail size, please do not use the term "marble" since
marbles come in a variety of sizes! For the most accurate report,
always report the size of the largest hailstones, preferably in
terms of diameter in inches.
- Lightning - Continuous lightning (more
than 6 flashes per minute)
-
Heavy
Rain - Half an inch or more per hour. Report heavy
rain even if you are outside a flood-prone area.
-
Heavy
Snow - We're looking for accumulations
of at least four inches in 12 hours or one inch per
hour.
-
Flooding - Any kind, including dam or
levee failure. We need to know if the waters are rising or
falling.
-
Damaging Wind - Trees or
power lines knocked down, damage to buildings, etc. Report any
wind of at least 40 MPH. Dictate if wind speed is estimated or
measured (by an anemometer). Use the Beaufort Wind Scale to
estimate wind speed.
-
Heavy
Fog, Blowing Dust or Blowing Snow - Report
initial onslaught of event when poor visibility impacts
travel.
Instructions for All Stations: It is
possible to report many types of weather information ranging from
trivial to critical; however, from the standpoint of the NWS, some
types of information are much more important than others. The
SKYWARNTM Event Reporting Criteria listed above
contain the types of information that are important to the NWS. All
stations are urged to follow these guidelines when deciding what to
report to the SKYWARNTM Net. Strict adherence to the
SKYWARNTM Event Reporting Criteria allows vital
information to be communicated as soon as possible and this in turn
should allow the SKYWARNTM Net to be operated more
efficiently.
Instructions for
SKYWARNTM Net Control Station (NCS),
Alternate NCS (ANCS), and Net Logging & Relay Station
(NLRS): Stations performing Net Control Operations for
the SKYWARNTM Net (the NCS, ANCS,
and NLRS) need to remember that hams are encouraged to report many
types of weather event occurrences during thunderstorms. While all
weather reports that meet the SKYWARNTM Event
Reporting Criteria are important, and need to be relayed to the NWS
at some point in time, there are some reports associated with
thunderstorms that are much more critical than others, and thus
require a higher handling priority in terms of when to relay them to
the NWS. When time is of the essence, the most critical reports need
to be relayed immediately! Do not wait for additional reports before
contacting the NWS, if you receive a report that requires priority
handling. In other words, when receiving reports associated with
thunderstorms, the reports that warrant higher handling priority should be
relayed first and they need to be relayed without delay! The
Priority Matrix below, categorizes weather events associated with
thunderstorms by their handling priority, and should be used to
determine the handling priority of weather reports. All of the
weather events in the Priority Matrix require higher handling
priority and must be relayed immediately to the NWS before relaying
reports of weather events of lesser importance. A report of a
weather event that is in the Priority Matrix is more urgent than a
report of a weather event that is not in the Priority Matrix;
therefore, it needs to be immediately relayed
to
the NWS!
Priority Matrix
|
Urgent
Priority |
High
Priority |
Low
Priority |
| Tornado |
Hail 3/4
inch diameter or larger |
Hail 1/2
inch diameter |
| Funnel
Cloud |
Wind
Speed 58mph or greater |
Wind
Speed 40mph or greater |
| Rotating
Wall Cloud |
Persistent non-rotating Wall Cloud |
Cloud
features suggesting storm organization |
| Flash
Flooding |
Rainfall
1/2 inch + per hour |
Rainfall less than 1/2
inch per hour |
| Property
damage |
Damaging
winds (usually greater than 50 mph) |
High
winds (40-50 mph) |
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