When Cleveland NWS issues a heavy snow warning, freezing rain/drizzle warning, heavy sleet warning, winter storm warning or blizzard warning, the NW Ohio Skywarn™ net will be activated. We MIGHT also be activated for various advisory statements. The net WILL NOT be activated for winter storm or blizzard WATCHES. These various warnings and advisories are explained below.
The net will be activated on the 147.375 repeater when an actual warning(or possibly an advisory) is in effect and snow or ice starts to fall in NW Ohio. The net will be activated on the top of each hour until 10 minutes after each hour to gather reports of snow or ice depth. The length of each session will be determined by the Net Control Station, but each session will be at least 10 minutes long. The NCS will also determine how long to keep these sessions running.
A "few" explanations may be in order because most people are not familiar with winter weather terms.
SNOW In a NWS forecast, without a qualifying word such as
occasional or intermittent, means that the fall of snow
is of a steady nature and probably will continue for
several hours without letup.
HEAVY SNOW In this part of Ohio, this means greater than or equal to
6" of accumulation in 24 hrs.
SLEET Frozen rain drops that bounce when hitting the ground or
other objects. Less than 1/2" accumulation. Sleet does
not coat trees or wires.
HEAVY SLEET Same as above, but greater than or equal to 1/2"
accumulation.
FREEZING RAIN Rain that occurs when the surface temperature is below
freezing. The moisture falls as a liquid, but freezes
upon impact, resulting in a coating of ice glaze on all
exposed objects.
BLOWING & Generally occur together and result from strong
DRIFTING SNOW winds and falling snow, or loose snow on the ground.
BLIZZARD This means that considerable falling and/or blowing
snow(visibility less than 1/4 mile) and sustained winds
of at least 35 mph are expected for several hours.
Temperatures are usually below 20 degrees F.
WIND CHILL The way that air of a given temperature, when added
INDEX with a given wind velocity, feels on exposed skin.
Winter weather events will fall into 1 of 3 different general
categories: WATCHES, ADVISORIES AND WARNINGS. WINTER STORM WATCHES may
be either changed to ADVISORIES or WARNINGS, as the storm gets closer
and the forecast becomes clearer. Advisories may also be upgraded to warnings.
WINTER STORM WATCH Issued within 36 hrs. of event. This is meant to
alert people to the possible occurrence of BLIZZARD
conditions, HEAVY SNOW conditions, FREEZING RAIN
conditions with accumulations of >0.5" of ice or
HEAVY SLEET conditions. This should be considered
as a kind of heads-up statement, and you should be
listening for later advisories or warnings.
ADVISORIES Issued within 12 hrs before the event. These may
describe specific events, or a more general
statement may be used. The different advisories
are:
1) SNOW 2 to 5 inches are expected.
2) BLOWING & Visibility intermittently
DRIFTING SNOW 1/4 mi. or less
3) WIND CHILL -25 to -34 degrees expected.
4) FREEZING RAIN Hazardous driving conditions
AND/OR up to 1/2" of ice.
5) WEATHER ADVISORIES If any 2 or more of
the above conditions might apply, then this
more general statement will be used. An
explanation of what to expect will be included
with this statement.
WARNINGS Issued within 12 hrs before the event. These may
describe specific events, or a more general
statement may be used. The different warnings are:
1) HEAVY SNOW greater than or equal to 6" in
24 hrs is expected.
2) WIND CHILL below -35 expected.
3) FREEZING RAIN Hazardous driving conditions
AND/OR greater than 1/2" of
ice.
4) WINTER STORM WARNINGS If any 2 or more
of the above conditions might apply, then this
more general statement will be used. An
explanation of what to expect will be included
with this statement.
BLIZZARD WARNING Expect blizzard conditions. If needed, this warning
will be seperate from the above warnings.
WATCH ADVISORY WARNING
SNOW >=6" 2-5" >=6" in 24 hrs.
FREEZING
RAIN >=1/2" <1/2" >=1/2"
SLEET >=1/2" <1/2" >=1/2"
WIND
CHILL N/A -25 to -34 F below -35 F
BLOWING &
DRIFTING SNOW N/A Visibility less N/A
than 1/4 mi.
Here is what we will be asking for when the nets are activated.
1) SNOW DEPTH REPORTS This measurement is actually an average of
three measurements. NWS requests that you use a normal ruler
and take the measurements of the snow in areas that seem to
represent the average depth. Add all three of these
measurements together and divide that # by three.
Example: Depth reading #1 4.75"
Depth reading #2 4.25"
Depth reading #3 6.00"
TOTAL 15.00"
Divide the TOTAL
by 3 5.00" This is what
you report.
Please do not take the depth measurement from that big drift
on the side of your house(or driveway!!). This is not a true
measurement. By the same thoughts, areas that have been blown
almost clear of snow are not representative of what's really
happening either.
2) ICE REPORTS We will begin taking reports of freezing rain as
soon as you realize that it is falling. Locating the rain-
freezing rain line is very important, so even if it's still
just raining in your area, we might be asking you to confirm
that. Remember, freezing rain is in liquid form until it hits
the ground, where it freezes on contact. Radar can't see this
happening - only spotters can.
We will NOT be running these nets all night long. We intend to
perhaps run them up until midnight, and then start up again at 5 am.
This, of course, will all depend on the timing of the storm.
The NWS usually issues snowfall maps at 7am and 7pm(0 and 1200z)
each day, and so in the case of an overnight event, they would like to
get the info by 6:30am. Other reason that they are asking for this
snowfall info is to know weather to upgrade an advisory a warning of
some type. NWS also tracks the rain-ice line during an ice storm to help
travelers know where to stay away from.
In trying to set up guidelines for the winter weather nets, we had
to keep in mind the longer-term events that these weather conditions
tend to be. This is the reasoning behind the 10 minute nets at each
hour. We also could not reasonably expect people to go out in the middle
of a cold, snowy night and measure the snow depth. That's why the nets
will usually be suspended from midnight to 4am(reopening at 5am, if
needed).
There is one other thing to keep in mind. When there is a winter
weather event taking place, ARES may also be activated to assist the
hospitals, or for other emergency communications as needed. These nets
will usually be run on repeaters OTHER THAN 147.375.
Steve Ashenfelter - N8XSF
Chris Taylor - N8WGB