While the peak occurrences for severe weather events in the United States happen between March and October, severe weather can occur at any time. In order to save lives, branches of the National Oceanic and Atmospheric Administration (NOAA) will issue public watches and warnings.
Knowing the difference between the two can prepare individuals for the necessary steps to take when considering the threat of severe weather. Watches and warnings issued to the public are based on different criteria.
"A watch is issued when conditions are favorable, for example, either for a severe thunderstorm or tornadoes," AccuWeather.com Senior Meteorologist Dan Kottlowski said. "It doesn't mean severe weather is imminent."
"Typical watches cover about 25,000 square miles, or about half the size of Iowa," according to the SPC.
Kottlowski said there are no set criteria for issuing watches, but if the conditions seem consistent with a developing severe weather pattern, watches can be changed and altered by monitoring ongoing developments.
"It can vary," he said. "There is not just one set of ingredients; every watch may have a different set of perimeters from one day to the next since it is based on a synoptic situation that may change within several hours."
Warnings mean that severe weather is imminent and is based on specific criteria and existing reports received by the NWS.
The criteria include hail that totals more than 1 inch in diameter and wind speeds of 55 mph.
"Lightning is not a criteria for a severe thunderstorm warning," Kottlowski said. "Heavy rain is not either."
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Warnings must follow the two main criteria, he said, adding urban flood and stream advisories, flash flood watches and warnings, and flood watches and warnings, may accompany a storm with heavy rain.
Warnings are issued through the efforts of individuals working for the NWS.
"The way a warning is issued is that a meteorologist will monitor the weather by radar and look for particular areas where there could be high impact damage," Kottlowski said. "They will issue a warning and there will be a signature for an existing storm or developing tornado."
Trained NWS spotters will verify reports of rotation or storm damage.
"This gives the meteorologists confidence in what they are seeing on radar," he said.
Lifeguards along the East and Gulf coasts are preparing to deal with one of the greatest beach dangers: rip currents.
A dangerous and life-threatening flooding situation will continue into Memorial Day, across portions of Texas, Oklahoma, Kansas, Arkansas and Missouri.
Showers and thunderstorms threaten to interfere with Memorial Day festivities across more than half of the United States.
Many areas in the Eastern states will have consistent summerlike heat and a buildup of humidity for the last week of May.
People heading to the Southeast coast for a dip in the Atlantic Ocean this Memorial Day holiday weekend are being put on alert for dangerous rip currents.
The second major tennis tournament of the year began on Sunday, as the world’s best tennis players begin their quest for the 2015 French Open title at Roland Garros in Paris.
Dallas, Ft. Worth Texas (1982)
Flooding rains in Dallas, Ft. Worth, area; over 2" in most places. Total rainfall of 13" at this point of the month, making it the wettest May since records began in 1898.
Wesley, LA (1991)
Heavy rain (25th-26th) resulted in widespread flooding. One hundred-sixty homes -- 80% of the total number of houses in town -- received structural or water damage. A total of 6.5" of rain fell in 2-1/2 hours.
Philadelphia, PA (1991)
96 degrees -- a record sixth 90-degree reading for the month. (The month ended with twelve 90-degree days.)