A Tornado Watch was issued by the National Weather Service in Memphis after a large storm producing a wedge tornado hit Jonesboro Arkansas on Saturday. The Watch covers Tippah County and much of North Mississippi.
From the NWS:
TORNADO WATCH 71 IS IN EFFECT UNTIL 200 AM CDT FOR THE
. MISSISSIPPI COUNTIES INCLUDED ARE
ALCORN BENTON BOLIVAR
COAHOMA DESOTO GRENADA
LAFAYETTE LEFLORE MARSHALL
PANOLA QUITMAN SUNFLOWER
TALLAHATCHIE TATE TIPPAH
TUNICA UNION WASHINGTON
This is issued by the National Weather Service when conditions are favorable for the development of tornadoes in and close to the watch area. Their size can vary depending on the weather situation. They are usually issued for a duration of 4 to 8 hours. They normally are issued well in advance of the actual occurrence of severe weather. During the watch, people should review tornado safety rules and be prepared to move to a place of safety if threatening weather approaches.
A Tornado Watch is issued by the Storm Prediction Center (SPC) in Norman, Oklahoma. Prior to the issuance of a Tornado Watch, SPC will usually contact the affected local National Weather Forecast Office (NWFO) and they will discuss what their current thinking is on the weather situation. Afterwards, SPC will issue a preliminary Tornado Watch and then the affected NWFO will then adjust the watch (adding or eliminating counties/parishes) and then issue it to the public. After adjusting the watch, the NWFO will let the public know which counties are included by way of a Watch Redefining Statement. During the watch, the NWFO will keep the public informed on what is happening in the watch area and also let the public know when the watch has expired or been cancelled.