...WINTER WEATHER TERMINOLOGY...

WHEN OLD MAN WINTER THREATENS, THE NATIONAL WEATHER SERVICE URGES
EVERYONE TO KEEP ABREAST OF LOCAL FORECASTS AND WARNINGS AND TO
BECOME FAMILIAR WITH KEY WINTER WEATHER TERMINOLOGY.

WINTER STORM OUTLOOK...THESE OUTLOOKS ARE ISSUED WITHIN THE
HAZARDOUS WEATHER OUTLOOK (HWO) PRODUCT. WINTER WEATHER HAZARDS ARE
MENTIONED WHEN CONDITIONS ARE FAVORABLE FOR A SIGNIFICANT HAZARDOUS
WINTER WEATHER EVENT TO DEVELOP OVER PART OR ALL OF CENTRAL ALABAMA
IN THE 3 TO 7 DAY FORECAST PERIOD. THE MAIN OBJECTIVE OF THE OUTLOOK
IS TO INFORM USERS OF THE POTENTIAL OF AN UPCOMING WINTER EVENT,
ESPECIALLY FOR THOSE WHO NEED CONSIDERABLE LEAD TIME TO PREPARE.

WINTER STORM WATCH...THESE POTENTIAL WINTER EVENTS ARE EXPECTED IN
THE 12 TO 48 HOUR TIME FRAME. FOR SNOW, WHEN MORE THAN 2 INCHES OF
SNOW ARE POSSIBLE IN A 12 HOUR TIME FRAME. FOR FREEZING RAIN OR
FREEZING DRIZZLE, ICE ACCUMULATIONS OF 0.25 INCH OR MORE. FOR
SLEET, ACCUMULATIONS OF ICE PELLETS ONE INCH OR MORE. FOR WIND
CHILL, WIND CHILLS OF -10 DEGREES OR COLDER.

WINTER STORM WARNING...THESE ARE WARNINGS THAT ARE ISSUED WHEN
HAZARDOUS WINTER WEATHER IS OCCURRING, IS IMMINENT OR HAS A HIGH
PROBABILITY OF OCCURRENCE. THESE POTENTIAL WINTER EVENTS ARE EXPECTED
IN THE 0 TO 36 HOUR TIME FRAME. FOR SNOW, WHEN MORE THAN 2 INCHES
OF SNOW ARE POSSIBLE IN A 12 HOUR TIME FRAME. FOR FREEZING RAIN OR
FREEZING DRIZZLE, ICE ACCUMULATIONS OF 0.25 INCHES OR MORE. FOR
SLEET, ACCUMULATIONS OF ICE PELLETS 1 INCH OR MORE. FOR WIND
CHILL, WIND CHILLS OF -10 DEGREES OR COLDER. IF FORECASTERS
CONFIDENCE IN A PREDOMINANT PRECIPITATION TYPE IS HIGH, THE WINTER
STORM WARNINGS CAN BE EVENT SPECIFIC SUCH AS HEAVY SNOW WARNING,
SLEET WARNING AND ICE STORM WARNING.

WINTER WEATHER ADVISORY...THESE ADVISORIES ARE ISSUED FOR WINTER
EVENTS THAT ARE OF SIGNIFICANCE TO THE PUBLIC BUT DO NOT
CONSTITUTE A SERIOUS ENOUGH THREAT TO LIFE AND PROPERTY TO WARRANT
THE ISSUANCE OF A WARNING. THESE ADVISORIES ARE ISSUED FOR LESSER
ACCUMULATIONS THAN WARNINGS.

WINTER WEATHER ADVISORIES ARE ISSUED FOR ACCUMULATIONS OF
SNOW, FREEZING RAIN, FREEZING DRIZZLE OR SLEET WHICH WILL CAUSE
SIGNIFICANT INCONVENIENCE AND MODERATELY DANGEROUS CONDITIONS. THESE
POTENTIAL WINTER EVENTS ARE EXPECTED IN THE 0 TO 36 HOUR TIME FRAME.
FOR SNOW, WHEN SNOW OF ONE QUARTER INCH TO TWO INCHES ACCUMULATING
WITHIN 12 HOURS. FOR SLEET, ACCUMULATION OF ICE PELLETS LESS THAN
ONE INCH. FOR FREEZING RAIN AND FREEZING DRIZZLE, ICE
ACCUMULATIONS LESS THAN ONE INCH ARE EXPECTED. FOR WIND CHILL,
WIND CHILLS OF ZERO TO -10 DEGREES.

WIND CHILL...WIND CHILL IS BASED ON THE RATE OF HEAT LOSS FROM
EXPOSED SKIN CAUSED BY THE COMBINED EFFECTS OF WIND AND COLD
TEMPERATURES. AS THE WIND INCREASES, HEAT IS CARRIED AWAY FROM THE
BODY AT AN ACCELERATED RATE, DRIVING DOWN THE BODY TEMPERATURE.
ANIMALS ARE ALSO AFFECTED BY WIND CHILL. INANIMATE OBJECTS SUCH AS
PIPES AND CAR RADIATORS ARE NOT AFFECTED. WHEN THE WIND CHILL
APPROACHES MINUS 20 DEGREES, FROSTBITE CAN OCCUR IN 15 MINUTES OR
LESS.

BLIZZARD WARNING...WARNING ISSUED FOR SUSTAINED WIND SPEEDS OR
FREQUENT GUSTS OF 35 MPH OR MORE AND FALLING AND/OR BLOWING SNOW
WHICH REDUCES VISIBILITIES TO LESS THAN ONE QUARTER OF A MILE FOR AT
LEAST 3 HOURS.

SNOW...FROZEN PRECIPITATION IN THE FORM OF WHITE OR TRANSLUCENT
HEXAGONAL ICE CRYSTALS THAT FALL AS SOFT, WHITE FLAKES.

SNOW GRAINS...PRECIPITATION OF VERY SMALL, WHITE, OPAQUE GRAINS OF
ICE SIMILAR IN STRUCTURE TO SNOW. THESE GRAINS ARE FAIRLY FLAT OR
ELONGATED. THE DIAMETERS ARE GENERALLY LESS THAN 1 MILLIMETER.

SNOW FLURRIES...INTERMITTENT LIGHT SNOWFALL OF SHORT DURATION.
GENERALLY LIGHT SNOW SHOWERS WITH NO MEASURABLE ACCUMULATION.

SNOW SHOWERS...BRIEF PERIODS OF SNOWFALL IN WHICH INTENSITY CAN BE
VARIED AND MAY CHANGE RAPIDLY. SOME ACCUMULATION IS POSSIBLE.

SNOW SQUALLS...BRIEF, INTENSE SNOW SHOWERS ACCOMPANIED BY
STRONG, GUSTY WIND. ACCUMULATION MAY BE SIGNIFICANT. SNOW SQUALLS
ARE BEST KNOW IN THE GREAT LAKES REGION.

HEAVY SNOW...SNOWFALL ACCUMULATING TO MORE THAN 2 INCHES IN DEPTH IN
12 HOURS OR LESS.

SLEET...RAIN DROPS THAT FREEZE INTO ICE PELLETS. THESE ARE
TRANSPARENT OR TRANSLUCENT PELLETS OF ICE OF 5 MILLIMETERS OR LESS IN
DIAMETER BEFORE REACHING THE GROUND. SLEET USUALLY BOUNCES WHEN
HITTING A SURFACE AND DOES NOT STICK TO OBJECTS. HOWEVER, IT CAN
ACCUMULATE LIKE SNOW AND CAUSE A HAZARD TO MOTORISTS AND
PEDESTRIANS.

FREEZING RAIN...RAIN THAT FALLS ONTO A SURFACE WITH A TEMPERATURE
BELOW FREEZING. THIS CAUSES IT TO FREEZE ON CONTACT WITH THESE
SURFACES. AN ICE COATING OR GLAZE CAN FORM ON TREES, CARS AND
ROADS. EVEN SMALL ACCUMULATIONS OF ICE CAN BECOME A SIGNIFICANT
HAZARD.

FREEZING DRIZZLE...DRIZZLE THAT FALLS ONTO A SURFACE WITH A
TEMPERATURE BELOW FREEZING. THIS CAUSES IT TO FREEZE ON CONTACT WITH
THESE SURFACES. AN ICE COATING OR GLAZE CAN FORM ON TREES, CARS AND
ROADS. EVEN SMALL ACCUMULATIONS OF ICE CAN BECOME A SIGNIFICANT
HAZARD. DRIZZLE PARTICLES ARE SMALLER THAN RAINDROPS AND TYPICALLY DO
NOT ACCUMULATE AS MUCH AS RAIN.

FROSTBITE...DAMAGE TO BODY TISSUE CAUSED BY TISSUE BEING FROZEN.
FROSTBITE CAUSES THE LOSS OF FEELING AND A WHITE OR PALE APPEARANCE
IN EXTREMITIES SUCH AS FINGERS, TOES, EAR LOBES OR THE TIP OF THE
NOSE. IF SYMPTOMS ARE DETECTED, SLOWLY WARM THE AFFECTED AREAS AND
SEEK MEDICAL HELP IMMEDIATELY.

HYPOTHERMIA...THE LOSS OF HEAT FROM THE BODY. WARNING SIGNS ARE
UNCONTROLLABLE SHIVERING, MEMORY LOSS AND DISTORTION. MEDICAL
TREATMENT SHOULD BE SOUGHT IMMEDIATELY.


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