Significant weather alert
Encyclopedia
A significant weather advisory, is issued when doppler weather radar indicates a strong thunderstorm
is producing small hail
or high winds
whose strength does not reach severe thunderstorm
criteria. It does not necessarily account for lightning
or flooding.
. Many versions of the First Warning
broadcast weather alert system have begun including significant weather alert into their systems, however, these systems usually classify such an advisory under the terms "Heavy T-Storms", "Heavy Storms" or "Strong T-Storms".
issues a significant weather advisory if hail size in a thunderstorm is less than 1 inch in diameter, and/or winds less than 58 miles per hour (90 km/h). These are mainly used in the NWS's southern region headquarters (SRH). Many NWS offices do not use the Significant Weather Advisory title and instead just use no warning text, though.
This product is not an official product, instead it is issued as a special weather statement
. Special weather statements are also used for any type of weather approaching watch/warning/advisory level. Many offices do not use significant weather advisories, instead issue normal special weather statements mentioning much of the same text used in a significant weather alert.
National Weather Service on July 14, 2011.
If severe weather
is detected, alerts (Severe Thunderstorm Warning
or Tornado Warning
) are issued by the National Weather Service
, and the Emergency Alert System
may activate and broadcast the alert. EAS alerts begin with a SAME
header, which sounds as three digital busts and automatically activates the EAS, a 1050 Hz attention signal, the alert as processed by text-to-speech software, then the SAME End of Message
tone to end the alert broadcast
. Also, sirens may be activated to warn the public who are not listening to media to take cover.
Thunderstorm
A thunderstorm, also known as an electrical storm, a lightning storm, thundershower or simply a storm is a form of weather characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere known as thunder. The meteorologically assigned cloud type associated with the...
is producing small hail
Hail
Hail is a form of solid precipitation. It consists of balls or irregular lumps of ice, each of which is referred to as a hail stone. Hail stones on Earth consist mostly of water ice and measure between and in diameter, with the larger stones coming from severe thunderstorms...
or high winds
WINDS
WINDS , is a Japanese communication satellite. Launch was originally scheduled for 2007. The launch date was eventually set for 15 February 2008, however a problem detected in a second stage manoeuvring thruster delayed it to 23 February...
whose strength does not reach severe thunderstorm
Thunderstorm
A thunderstorm, also known as an electrical storm, a lightning storm, thundershower or simply a storm is a form of weather characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere known as thunder. The meteorologically assigned cloud type associated with the...
criteria. It does not necessarily account for lightning
Lightning
Lightning is an atmospheric electrostatic discharge accompanied by thunder, which typically occurs during thunderstorms, and sometimes during volcanic eruptions or dust storms...
or flooding.
History
This forecast product was created in the early 2000s, and is sometimes a precursor to a severe thunderstorm warningSevere thunderstorm warning
A severe thunderstorm warning is issued when trained storm spotters or a Doppler weather radar indicate a strong thunderstorm is producing dangerously large hail or high winds, capable of causing significant damage. In the United States, it does not account for lightning or flooding...
. Many versions of the First Warning
First Warning
First Warning is the name of a severe weather warning system made for broadcast television stations in the United States. A weather advisory product based on First Warning, called First Alert, is an automated version of this product, which has come into widespread use by television stations.Both...
broadcast weather alert system have begun including significant weather alert into their systems, however, these systems usually classify such an advisory under the terms "Heavy T-Storms", "Heavy Storms" or "Strong T-Storms".
Criteria
The National Weather ServiceNational 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...
issues a significant weather advisory if hail size in a thunderstorm is less than 1 inch in diameter, and/or winds less than 58 miles per hour (90 km/h). These are mainly used in the NWS's southern region headquarters (SRH). Many NWS offices do not use the Significant Weather Advisory title and instead just use no warning text, though.
This product is not an official product, instead it is issued as a special weather statement
Special weather statement
A Special weather statement is a form of weather advisory. Special weather statements are issued by the National Weather Service of the United States and the Meteorological Service of Canada...
. Special weather statements are also used for any type of weather approaching watch/warning/advisory level. Many offices do not use significant weather advisories, instead issue normal special weather statements mentioning much of the same text used in a significant weather alert.
Example of a significant weather advisory
The following example of a significant weather advisory was issued by the Norman, OklahomaNorman, Oklahoma
Norman is a city in Cleveland County, Oklahoma, United States, and is located south of downtown Oklahoma City. It is part of the Oklahoma City metropolitan area. As of the 2010 census, Norman was to have 110,925 full-time residents, making it the third-largest city in Oklahoma and the...
National Weather Service on July 14, 2011.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORMAN OK
1251 AM CDT THU JUL 14 2011
OKZ015-140600-
DEWEY OK-
1251 AM CDT THU JUL 14 2011
...SIGNIFICANT WEATHER ADVISORY...
THIS SIGNIFICANT WEATHER ADVISORY IS FOR DEWEY COUNTY.
AT 1251 AM CDT...A STRONG THUNDERSTORM WAS LOCATED OVER CAMARGO...
MOVING EAST AT 15 MPH.
HAZARDS INCLUDE...
HAIL UP TO ONE-HALF INCH...
WIND GUSTS TO 50 MPH...
MINOR FLOODING IN AREAS OF POOR DRAINAGE...
SEVERE WEATHER IS NOT EXPECTED AND NO WARNINGS ARE ANTICIPATED AT
THIS TIME.
LAT...LON 3613 9899 3593 9900 3595 9934 3613 9933
$$
WR
If severe weather
Severe weather
Severe weather phenomena are weather conditions that are hazardous to human life and property.- Examples Include :Severe weather can occur under a variety of situations, but three characteristics are generally needed: a temperature or moisture boundary, moisture, and , instability in the...
is detected, alerts (Severe Thunderstorm Warning
Severe thunderstorm warning
A severe thunderstorm warning is issued when trained storm spotters or a Doppler weather radar indicate a strong thunderstorm is producing dangerously large hail or high winds, capable of causing significant damage. In the United States, it does not account for lightning or flooding...
or Tornado Warning
Tornado warning
A tornado warning is an alert issued by government weather services to warn that severe thunderstorms with tornadoes may be imminent. It can be issued after a tornado or funnel cloud has been spotted by eye, or more commonly if there are radar indications of tornado formation...
) are issued by the National Weather Service
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...
, and the Emergency Alert System
Emergency Alert System
The Emergency Alert System is a national warning system in the United States put into place on January 1, 1997, when it superseded the Emergency Broadcast System , which itself had superseded the CONELRAD System...
may activate and broadcast the alert. EAS alerts begin with a SAME
Specific Area Message Encoding
Specific Area Message Encoding or SAME is the protocol used to encode the Emergency Alert System and NOAA Weather Radio's SAME Public Warning System in the U.S...
header, which sounds as three digital busts and automatically activates the EAS, a 1050 Hz attention signal, the alert as processed by text-to-speech software, then the SAME End of Message
End of Message
End of message or EOM signifies the end of a message, often an e-mail. The subject of an e-mail may contain such an abbreviation to signify that all content is in the subject line so that the message itself does not need to be opened...
tone to end the alert broadcast
Broadcast
Broadcast or Broadcasting may refer to:* Broadcasting, the transmission of audio and video signals* Broadcast, an individual television program or radio program* Broadcast , an English electronic music band...
. Also, sirens may be activated to warn the public who are not listening to media to take cover.