Post by James on Dec 2, 2007 11:51:39 GMT -5
Winter Storm Outlook
Issued 3-7 days in advance for anticipated snow/ice
Winter Storm Watch
A winter storm watch is issued when there is the potential for significant and hazardous winter weather within 48 hours. It does not mean that significant and hazardous winter weather will occur...it only means it is possible.
Significant and hazardous winter weather is defined as:
1) Over 5 inches of snow (and/or sleet)
OR
2) Glaze accumulation (freezing rain) of 1/4 inch or more
OR
3) Enough ice accumulation to cause damage to trees or powerlines.
OR
4) a life threatening or damaging combination of snow and/or ice accumulation with wind.
Blizzard Warning
A Blizzard Warning means that the following conditions are occurring or expected within the next 12 to 18 hours.
1) Snow and/or blowing snow reducing visibility to 1/4 mile or less for 3 hours or longer
AND
2) Sustained winds of 35 mph or greater or frequent gusts to 35 mph or greater.
There is no temperature requirement that must be met to achieve blizzard conditions.
Winter Storm Warning
A winter storm warning is issued when a significant combination of hazardous winter weather is occurring or imminent.
Significant and hazardous winter weather is defined as a combination of:
1) Over 5 inches of snow/sleet
AND/OR
2) Glaze accumulation (freezing rain) of 1/4 inch or more
AND/OR
3) Enough ice accumulation to cause damage to trees or powerlines.
AND/OR
4) a life threatening or damaging combination of snow and/or ice
accumulation with wind.
Heavy Snow Warning
5 inches or more of snow in 12 hours. 7 inches or more in 24 hours.
Ice Storm Warning
ΒΌ inch or more of ice accumulation
Snow Advisory
2-4 inches of snow in a 12 hour period
Freezing Rain Advisory
Ice accumulations of less than 1/4 inch
Winter Weather Advisory
A winter weather advisory is issued when snow, sleet, freezing rain, or
a combination of precipitation types is expected to cause a significant
inconvenience but not serious enough to warrant a warning.
Freeze Warning
A freeze warning is issued when significant, widespread freezing temperatures are expected.
A freeze warning is issued in the autumn until October 15th west of a line from
Frederick, Maryland to Charlottesville, Virginia. It is issued in the autumn until
November 1st east of that line.
A freeze warning is issued in the spring when it is late enough to cause damage to
new plants and crops.
Frost Warning
A frost warning is issued when significant, widespread frost is expected.
A frost warning is issued in the autumn until October 15th west of a line from
Frederick, Maryland to Charlottesville, Virginia. It is issued in the autumn
until November 1st east of that line.
A frost warning is issued in the spring when it is late enough to cause damage
to new plants and crops.
Wind Chill Advisory
A wind chill advisory is issued when wind chills of -5F to -19F are expected.
Wind Chill Warning
A wind chill warning is issued when wind chills of -20F or lower are expected.
Issued 3-7 days in advance for anticipated snow/ice
Winter Storm Watch
A winter storm watch is issued when there is the potential for significant and hazardous winter weather within 48 hours. It does not mean that significant and hazardous winter weather will occur...it only means it is possible.
Significant and hazardous winter weather is defined as:
1) Over 5 inches of snow (and/or sleet)
OR
2) Glaze accumulation (freezing rain) of 1/4 inch or more
OR
3) Enough ice accumulation to cause damage to trees or powerlines.
OR
4) a life threatening or damaging combination of snow and/or ice accumulation with wind.
Blizzard Warning
A Blizzard Warning means that the following conditions are occurring or expected within the next 12 to 18 hours.
1) Snow and/or blowing snow reducing visibility to 1/4 mile or less for 3 hours or longer
AND
2) Sustained winds of 35 mph or greater or frequent gusts to 35 mph or greater.
There is no temperature requirement that must be met to achieve blizzard conditions.
Winter Storm Warning
A winter storm warning is issued when a significant combination of hazardous winter weather is occurring or imminent.
Significant and hazardous winter weather is defined as a combination of:
1) Over 5 inches of snow/sleet
AND/OR
2) Glaze accumulation (freezing rain) of 1/4 inch or more
AND/OR
3) Enough ice accumulation to cause damage to trees or powerlines.
AND/OR
4) a life threatening or damaging combination of snow and/or ice
accumulation with wind.
Heavy Snow Warning
5 inches or more of snow in 12 hours. 7 inches or more in 24 hours.
Ice Storm Warning
ΒΌ inch or more of ice accumulation
Snow Advisory
2-4 inches of snow in a 12 hour period
Freezing Rain Advisory
Ice accumulations of less than 1/4 inch
Winter Weather Advisory
A winter weather advisory is issued when snow, sleet, freezing rain, or
a combination of precipitation types is expected to cause a significant
inconvenience but not serious enough to warrant a warning.
Freeze Warning
A freeze warning is issued when significant, widespread freezing temperatures are expected.
A freeze warning is issued in the autumn until October 15th west of a line from
Frederick, Maryland to Charlottesville, Virginia. It is issued in the autumn until
November 1st east of that line.
A freeze warning is issued in the spring when it is late enough to cause damage to
new plants and crops.
Frost Warning
A frost warning is issued when significant, widespread frost is expected.
A frost warning is issued in the autumn until October 15th west of a line from
Frederick, Maryland to Charlottesville, Virginia. It is issued in the autumn
until November 1st east of that line.
A frost warning is issued in the spring when it is late enough to cause damage
to new plants and crops.
Wind Chill Advisory
A wind chill advisory is issued when wind chills of -5F to -19F are expected.
Wind Chill Warning
A wind chill warning is issued when wind chills of -20F or lower are expected.