The National Weather Service defines a blizzard as having
strong winds greater than 35 mph, combined with heavy or blowing
snow to produce "very poor visibility." Visibility needs to be
under a quarter-mile to qualify as a blizzard.
NOR'EASTER
The swirling storms that typically bring heavy snow, rain, and
coastal flooding to areas in the Northeast are known as
"Nor'easters." The storms moving up the East Coast of the U.S.
received their name, because their winds typically blow from the
northeast, even though the storm is moving from southeast to
northeast. That is because the winds are moving in a
counter-clockwise around the area of low pressure.
BOMB CYCLONE
Winter storms that strengthen rapidly, including nor'easters,
are dubbed "bomb cyclones." The term “bombogenesis” comes from
mid-latitude storms that intensify rapidly, dropping 24
millibars (atmospheric pressure) over a 24-hour span, according
to the National Oceanic and Atmospheric Administration (NOAA). A
typical range in millibar change is around 10 to 15 in 24 hours.
A bombogenesis storm can be tropical or non-tropical. “The term
bombogenesis comes from the merging of two words: bomb and
cyclogenesis. All storms are cyclones, and genesis means the
creation or beginning.
SLEET
Sleet is known as a combination of a snowflake and water that is
frozen, according to forecasters. One of the types of
precipitation people commonly describe as "hail" is actually
sleet. Sleet is ice pellets or granulates of frozen rain, and
occurs when rain falls through air with temperatures below
freezing, according to the NWS. While the raindrop is falling,
if it goes through above-freezing air, it turns back into
liquid-- until it refreezes before hitting the ground.
FREEZING RAIN
Freezing rain is defined as rain that falls and lands on a
surface with a temperature that is below freezing, causing it to
freeze on contact. The rain that falls and freezes eventually
forms a coating of ice or glaze that can make walking or driving
extremely difficult. A freeze may or may not be accompanied by a
frost, which is the formation of ice crystals that develop when
dew gathers in temperatures of at least 32 degrees. A flash freeze occurs when
temperatures drop quickly below 32 degrees and cause a rapid
freeze.
BLACK ICE
When there is a flash freeze, water on untreated surfaces can
form "black ice." If the water present is very thin and on a
surface such as black asphalt, it can be difficult to see. It
can be extremely dangerous and very slippery.
SNOW SHOWERS AND SNOW
SQUALLS
The NWS counts snow showers as snow falling with varying
intensity over brief periods, possibly accumulating. Snow
squalls, however, are more intense snow showers and the most
common. Brief, intense weather is typically accompanied by
strong, gusty winds and may produce significant accumulations.
WIND CHILL AND
ACCUWEATHER REALFEEL
In addition to temperatures on a thermometer, "wind chill" tells
us how it feels outside. The NWS defines a wind chill index as
the apparent temperature, plus the effect of falling
temperatures and the rate of heat loss from a human body, caused
by the wind.
"As the wind increases,
heat is carried away from a person's body at a more accelerated
rate, driving down the body temperature," according to the NWS.
The only effect wind chill has on inanimate objects, such as car
radiators and water pipes, is to more quickly cool the object to
the current air temperature. The object will not cool below the
actual air temperature.