Excessive heat warning
Encyclopedia
An Excessive Heat Warning is issued by the National Weather Service
of the United States
within 12 hours of the heat index
reaching one of two criteria levels. A warning will be issued if there is a heat index of at least 105°F for more than 3 hours per day for 2 consecutive days, or if the heat index is greater than 115°F for any period of time. High values of the heat index are caused by temperatures being significantly above normal and high humidities
, and such high levels can pose a threat to human life through condidtions such as heat stroke, Heat exhaustion, and other heat-related illnesses.
on July 20, 2011 during a severe heat wave.
THE EVENING. THE HEAT INDEX WILL RISE TO BETWEEN 105 AND 110
THURSDAY AFTERNOON AND EVENING AND THEN AGAIN ON FRIDAY.
ILLNESSES WILL BE POSSIBLE...ESPECIALLY IF YOU SPEND A
SIGNIFICANT AMOUNT OF TIME OUTDOORS...OR ARE INVOLVED IN ANY
STRENUOUS OUTDOOR ACTIVITY.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE EXTRA PRECAUTIONS IF YOU WORK OR SPEND TIME OUTSIDE. WHEN
POSSIBLE... RESCHEDULE STRENUOUS ACTIVITIES TO EARLY MORNING OR
EVENING. KNOW THE SIGNS AND SYMPTOMS OF HEAT EXHAUSTION AND HEAT
STROKE. WEAR LIGHT WEIGHT AND LOOSE FITTING CLOTHING WHEN
POSSIBLE AND DRINK PLENTY OF WATER.
TO REDUCE RISK DURING OUTDOOR WORK THE OCCUPATIONAL SAFETY AND
HEALTH ADMINISTRATION RECOMMENDS SCHEDULING FREQUENT REST BREAKS
IN SHADED OR AIR CONDITIONED ENVIRONMENTS. ANYONE OVERCOME BY
HEAT SHOULD BE MOVED TO A COOL AND SHADED LOCATION. HEAT STROKE
IS AN EMERGENCY...CALL 911.
&&
$$
National Weather Service
The National Weather Service , once known as the Weather Bureau, is one of the six scientific agencies that make up the National Oceanic and Atmospheric Administration of the United States government...
of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
within 12 hours of the heat index
Heat index
The heat index is an index that combines air temperature and relative humidity in an attempt to determine the human-perceived equivalent temperature — how hot it feels, termed the felt air temperature. The human body normally cools itself by perspiration, or sweating, which evaporates and carries...
reaching one of two criteria levels. A warning will be issued if there is a heat index of at least 105°F for more than 3 hours per day for 2 consecutive days, or if the heat index is greater than 115°F for any period of time. High values of the heat index are caused by temperatures being significantly above normal and high humidities
Relative humidity
Relative humidity is a term used to describe the amount of water vapor in a mixture of air and water vapor. It is defined as the partial pressure of water vapor in the air-water mixture, given as a percentage of the saturated vapor pressure under those conditions...
, and such high levels can pose a threat to human life through condidtions such as heat stroke, Heat exhaustion, and other heat-related illnesses.
Example
The following is an example of an Excessive Heat Warning issued by the National Weather Service office in Wilmington, OhioWilmington, Ohio
Wilmington is a city in and the county seat of Clinton County, Ohio, United States. The population was 12,520 at the 2010 census. At city entrances from state routes, county roads, and U.S. highways, the city slogan of "We Honor Our Champions" is seen, accompanied by signs that highlight various...
on July 20, 2011 during a severe heat wave.
URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE WILMINGTON OH
944 PM EDT WED JUL 20 2011
KYZ099-100-OHZ026-045-046-052>056-062>065-072>074-079>082-088-
211000-
/O.CON.KILN.EH.W.0002.110721T1600Z-110723T0100Z/
/O.CON.KILN.HT.Y.0004.000000T0000Z-110721T1600Z/
MASON-LEWIS-HARDIN-UNION OH-DELAWARE-CHAMPAIGN-CLARK-MADISON-
FRANKLIN OH-LICKING-GREENE-FAYETTE OH-PICKAWAY-FAIRFIELD-CLINTON-
ROSS-HOCKING-BROWN-HIGHLAND-ADAMS-PIKE-SCIOTO-
INCLUDING THE CITIES OF...MAYSVILLE...VANCEBURG...KENTON...
MARYSVILLE...DELAWARE...URBANA...SPRINGFIELD...LONDON...
COLUMBUS...NEWARK...XENIA...WASHINGTON COURT HOUSE...
CIRCLEVILLE...LANCASTER...WILMINGTON...CHILLICOTHE...LOGAN...
GEORGETOWN...HILLSBORO...WEST UNION...PIKETON...PORTSMOUTH
944 PM EDT WED JUL 20 2011
...HEAT ADVISORY REMAINS IN EFFECT UNTIL NOON EDT THURSDAY...
...EXCESSIVE HEAT WARNING REMAINS IN EFFECT FROM NOON THURSDAY TO
9 PM EDT FRIDAY...
- HEAT INDEX VALUES...UP TO 110.
- TIMING...HEAT INDICES BETWEEN 100 AND 105 WILL CONTINUE INTO
THE EVENING. THE HEAT INDEX WILL RISE TO BETWEEN 105 AND 110
THURSDAY AFTERNOON AND EVENING AND THEN AGAIN ON FRIDAY.
- IMPACTS...HEAT EXHAUSTION...HEAT STROKE AND OTHER HEAT RELATED
ILLNESSES WILL BE POSSIBLE...ESPECIALLY IF YOU SPEND A
SIGNIFICANT AMOUNT OF TIME OUTDOORS...OR ARE INVOLVED IN ANY
STRENUOUS OUTDOOR ACTIVITY.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE EXTRA PRECAUTIONS IF YOU WORK OR SPEND TIME OUTSIDE. WHEN
POSSIBLE... RESCHEDULE STRENUOUS ACTIVITIES TO EARLY MORNING OR
EVENING. KNOW THE SIGNS AND SYMPTOMS OF HEAT EXHAUSTION AND HEAT
STROKE. WEAR LIGHT WEIGHT AND LOOSE FITTING CLOTHING WHEN
POSSIBLE AND DRINK PLENTY OF WATER.
TO REDUCE RISK DURING OUTDOOR WORK THE OCCUPATIONAL SAFETY AND
HEALTH ADMINISTRATION RECOMMENDS SCHEDULING FREQUENT REST BREAKS
IN SHADED OR AIR CONDITIONED ENVIRONMENTS. ANYONE OVERCOME BY
HEAT SHOULD BE MOVED TO A COOL AND SHADED LOCATION. HEAT STROKE
IS AN EMERGENCY...CALL 911.
&&
$$