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For Snow alone: |
Winter Storm
Warning for Heavy Snow: Severe winter weather is occrruing, imminent,
or highly likely within 12 to 24 hours.
Heavy Snow Warning:An average of 4" or more of snowfall
in 12 hrs, or an average of 6" or more of snowfall in 24 hrs.
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| Snow Advisory:
An average of 1" to 3" of snowfall in 12 hrs or less. |
| Winter Storm
Watch: Significant snow, freezing rain, or ice is expected within
24 to 36 hours. |
| Blowing/Drifting Snow Advisory: Snow that is expected to
significantly reduce visibility. |
For Ice alone: |
| Ice Storm
Warning: When damaging accumulation of ice are expected during
freezing rain situations. Accumulations of 1/4 inch or greater would
be expected. |
| Freezing
Rain/Drizzle Advisory: Light accumulation of freezing rain or
drizzle that does not form on exposed surfaces. |
| Heavy Sleet Warning: Accumulation of ice pellets is expected
to cover the ground to a depth of 1/2 inch or more. |
Combinations of Winter Weather Hazards: |
| BLIZZARD WARNING:
Sustained or frequent gusts to 35 mph or greater AND considerable
falling and/or blowing snow which reduces the visibility to 1/4 mile
or less. These conditions must last for AT LEAST 3 hrs. |
Non Precipitation Phenomena Warning Terminology |
| Winds
NOT associated with a specific Thunderstorm:
Wind Advisory:
sustained winds 31 to 39 mph, for better than 1 hour - and/or wind
gusts 46 to 57 mph for any duration.
High Wind Warning: sustained winds 40 mph or greater, for
better than 1 hour - and/or wind gusts 58 mph or greater, for any
duration. |
| Cold Wind
Chills:
Wind Chill Warning: wind chills values of minus 25°F
or lower.
Wind Chill Advisory: wind chill values of minus 15°F
to minus 24°F.
Widespread Frosts/Freezes, after the beginning (and before
the end) of the "growing season":
The growing season is variable each year, but normally runs from
late-April/mid-May through late-Sep/late-Oct.
Frost Advisory: a widespread frost, typically with low temperatures
near or slightly below freezing.
Freeze Warning: low temperatures at or below 32°F. |
| For High
Heat Indicies:
Heat Advisory: heat index greater than or equal to 105°F
and less than 115°F for less than 3 hrs/day. Also, nighttime
heat indicies should remain above 80°F.
Excessive Heat Warning: Heat indicies 105>115°F for
more than 3hrs per day for at least 2 consecutive days, or eclipse
115°F for any length of time.
For Widespread Dense Fog:
Dense Fog Advisory: widespread areas of fog reducing the visibility
to less than 1/4 mile.
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