General Weather Information

‚ÄčJacksonville University is located in Northeast Florida, where we sometimes experience severe weather like heavy thunderstorms, lightning, tornadoes, and, on rare occasions in the winter, ice storms and light snowfall. Weather-related emergencies have the potential to cause significant damage to buildings and property on campus, and can also pose a threat to the safety of our students and staff.

Definitions

Severe Thunderstorms

A thunderstorm is considered severe if it produces hail at least 1 inch in diameter or has wind gusts of at least 58 miles per hour.

Tornado

A tornado is a violently rotating column of air extending from the base of a thunderstorm down to the ground. Tornadoes can occur at any time of day or night and at any time of the year.

Tornado Watch

Issued when the National Weather Service has determined that tornadoes are possible in the area. Remain alert for approaching storms.

Tornado Warning

Issued when the National Weather Service has determined that a tornado is occurring, or is likely to occur within minutes, in the specified area. Warnings indicate imminent danger to life and property because a tornado or tornadoes have been sighted in the area.

Lightning and Flood Threats

While much of the focus during severe weather is on tornadoes, wind and hail, there are actually more deaths caused each year by flooding and lighting, which are also commonly associated with severe weather. If you hear thunder or see lighting, head inside immediately! Stay in safe shelter at least 30 minutes after you hear the last sound of thunder. Heavy rainfall from thunderstorms can quickly cause rivers and streams to over flow and cause street flooding. Reminder, if you encounter a flooded road/ street, do not attempt to drive or walk into it.

Hurricane

A hurricane is a tropical cyclone in which winds reach a constant speed of at least 74 miles per hour (mph) and may gust to 200 mph. Spiral clouds may cover an area several hundred miles in diameter. The spirals are heavy cloud bands from which torrential rains fall and tornados may be generated. The eye of the hurricane is deceptively calm and almost free of clouds with light winds and warm temperatures. Beyond the eye, counter clockwise winds bring destruction and death to coastlines and islands in their erratic path. It is important to remember that the position of the storm given by The National Hurricane Center is the eye of the storm. High winds and heavy rain may extend up to 200 miles from the eye. Hazardous conditions may arrive six to ten hours before the eye makes landfall.

Hurricane Season

The portion of the year having a relatively high incidence of hurricanes. The hurricane season in the Atlantic, Caribbean, and Gulf of Mexico runs from June 1 to November 30.

Advisory

A National Weather Service message giving storm location, intensity, movement, and precautions to be taken.

Eye

The roughly circular area of comparatively light winds and fair weather at the center of a hurricane. Eyes are usually 25-30 miles in diameter. The area around the eye is called the wallcloud. (Do not go outdoors while the eye is passing; the full intensity of the storm will reoccur in minutes.)

Hurricane Watch

Issued by The National Hurricane Center when a hurricane threatens, the watch covers a specified area and time period. A hurricane watch indicates hurricane conditions are possible, usually within 48 hours, but it does not mean that will happen. When a watch is issued, listen for advisories and be prepared to take action if advised to do so.

Hurricane Warning

A warning is issued by The National Hurricane Center 36 hours before hurricane conditions (winds greater than 73 mph) are expected. If the hurricane path changes quickly, the warning may be issued 10 to 18 hours, or less, before the storm makes landfall. A warning will also identify where dangerously high water and waves are forecast even though winds may be less than hurricane force.

Hurricane Landfall

The point and time during which the eye of the hurricane passes over the shoreline. After passage of the calm eye, hurricane winds begin again with the same intensity as before, but from the opposite direction.

Hurricane Local Statement

A public release prepared by local National Weather Service offices in or near a threatened area giving specific details for its county warning area on (1) weather conditions, (2) evacuation decisions made by local officials, and (3) other precautions necessary to protect life and property.

Storm Surge

A dome of seawater, often 50 miles across, that sweeps the coast line inundating the land with up to 15 feet of water above normal high tide. The ocean level rises as a hurricane approaches, peaking where the eye strikes land, and gradually subsiding after the hurricane passes. Storm surge, also known as tidal flooding, has been responsible for nine out of ten hurricane deaths. View the 2013 Surge Map.

Tropical Storm

An area of low pressure with a definite eye and counter clockwise winds of 39-73 mph. A tropical storm may strengthen to hurricane force in a short period of time.

Tropical Storm Warnings

Issued by The National Hurricane Center when winds of 55-73 mph (48-63 knots) are expected. If a hurricane is expected to strike a coastal area, separate tropical storm warnings will not usually precede hurricane warnings.