Severe Storms
This weather event is defined by heavy rainfall accompanied by lightning and thunder.
What is a thunderstorm?
A prolonged period with little to no precipitation that leads to severe water shortages and crop damage.
What is a drought?
Issued 1 to 8 days in advance over a broad area, this type of National Weather Service alert carries the public directive: "BE AWARE!"
What is a Weather Outlook?
Essentially a stratus cloud that forms at or near ground level due to condensation, this hazard impairs driving visibility.
What is fog?
For a tropical weather system over the ocean to officially be classified as a hurricane, its sustained wind speeds must reach at least this threshold.
What is 74 mph?
This violently rotating column of air extends from a storm cloud to the ground, with top winds capable of reaching 300 mph.
What is a tornado?
This sudden hydrological event occurs during intense rainfall and is documented as the #1 weather-related cause of death in the United States.
What is a flash flood?
Issued for conditions that are hazardous to travel but not severe (such as light snow or brisk winds), this alert means "BE CAREFUL!"
What is a Weather Advisory?
In arid regions, strong winds lifting loose soil and sediment create this sudden, short-term hazard that often lasts less than three minutes.
What is a dust storm (or sandstorm)?
Thunderstorm formation universally requires three key atmospheric ingredients: moisture, lift, and WHAT OTHER condition.
What is unstable air (or atmospheric instability)?
This tropical cyclone forms over warm oceans with winds exceeding 74 mph and creates destructive storm surges along coastlines.
What is a hurricane?
Unlike a blizzard, this gentler winter storm is characterized by freezing rain that coats trees, roads, and power lines in at least 0.25 inches of ice.
What is an ice storm?
When atmospheric conditions become favorable for storms to develop hours ahead of time, the NWS issues this alert meaning "BE PREPARED!"
What is a Weather Watch?
In addition to blinding motorists, dust storms present this primary biological hazard when particles enter the eyes, nose, and mouth.
What is respiratory irritation (or damage to lungs/breathing passages)?
Large hail requires cold upper-air temperatures and very powerful columns of this rapidly rising warm air inside the storm cloud.
What are updrafts?
Severe weather most often erupts along boundaries where these two contrasting types of air masses collide.
What are warm/moist air and cold/dry air?
To officially qualify as this type of severe winter storm, an event must combine intense snowfall with strong, sustained winds that drastically drop visibility.
What is a blizzard?
This urgent alert means a dangerous weather event is imminent or actively occurring: "TAKE ACTION!"
What is a Weather Warning?
This seasonal wind shift brings heavy summer rainfall to Southern Asia, West Africa, and Australia, preventing severe regional drought.
What is a monsoon?
[SEE MAP] On national risk maps, the highest concentration of severe hail risk across the United States is located in this central region.
What is the Great Plains (or Central Plains / "Hail Alley")?
Tornado Alley forms primarily where cold, dry Canadian air meets warm, moist air streaming north from this specific body of water.
What is the Gulf of Mexico?
This intense mid-latitude cyclone forms off the East Coast or Gulf of Mexico, tracking northward with heavy snow and hurricane-force winds.
What is a Nor'easter?
While hurricane alerts can be provided days ahead, the NWS often issues these two specific warnings only minutes before impact.
What are Tornado Warnings and Flash Flood Warnings?
Despite occurring in different climates and seasons, blizzards, fog, and dust storms all share this exact same physical hazard for travel.
What is severely reduced visibility?
Computer simulations show that tornadic rotation inside a supercell thunderstorm requires warm, moist inflow interacting with this downdraft wrapping around the back of the storm.
What is a rear flank downdraft (RFD)?