Today's UVI Index Alert Is NOT 'Extreme'

The UV Alert is "very high" for the Tamap Bay area Aug. 20, and also for 19 other cities in the nation where the ultraviolet index forecast is 8, 9 or 10. The only higher alert is "extreme," which today has been issued for 10 cities.

Valid for "solar noon," the Aug. 20 UV Index forecast for the Tampa Bay area is 9.

This is the fourth-highest forecast among the 58 readings taken and the same UV Index forecast for Charleston, Dallas, Denver, Jackson, Jacksonville, Norfolk, Oklahoma City, Salt Lake City and San Francisco (see chart below).

The highest UV Index for Aug. 20 is 12, forecast for Honolulu, Miami and San Juan, followed by 11, forecast for Albuquerque, Los Angeles and New Orleans. Also given an "exteme" alert, with a 10, are Houston, Las Vegas, Mobile and Phoenix.

The lowest UV Index is 2, forecast for both Anchorage. Next lowest is 5, forecast for Hartford.

What Is the UV Index

The UVI is "the next-day forecast for the amount of skin-damaging radiation expected to reach the earth's surface at the time when the sun is highest in the sky," according to the National Weather Service.

The UV Index ranges from O (at night) to 16 (as in the tropics, at high elevations under clear skies).

The higher the UV Index, the greater the "dose rate" of skin- and eye-damaging ultraviolet radiation, according to the National Weather Service.

The UV Index is categorized by the World Health Organization as follows:

• LOW — 0, 1, 2
• MODERATE — 3, 4, 5
• HIGH — 6, 7 
• VERY HIGH — 8, 9, 10
• EXTREME — 11-16

Overexposure Risks

According to the National Weather Service, overexposure to ultraviolet radiation can cause the following:

• Severe sunburn, following an intense, short-term overxposure.

• Melanoma, the more deadly of the two types of skin cancer, following several intense, short-term overxosures.

• Non-melanoma skin cancers, which are almost 100 percent curable after overexposure for very long periods of time, as is experienced typically by construction workers, farmers and fishermen.

• Catracts in the eyes, also following long-term exposure.

SUN-SAFETY TIPS

The Hillsborough County Extension Office, through the University of Florida Institute of Food and Agricultural Sciences, offers the following tips for avoiding the dangers of overexposure:

Do Not Burn

• Five or more sunburns can double the chances of getting skin cancer.

Monitor UV Levels

• Limit outdoor activities between 10 a.m. and 4 p.m. when the UV Index is "high" (6 or 7), "very high" (8, 9 or 10) or "extreme" (11 or higher).

Apply Lots of Sunscreen

• Apply a broad-spectrum sunscreen (SPF of at least 15) 20 minutes before going outside. Re-apply the sunscreen again every two hours, and after swimming or sweating.

Protect Head and Eyes

• Wear wide-brimmed hats for better sun protection. Wear sunglasses with 99-100 percent UV-A and UV-B protection.

Use Extra Caution Near Water and Sand

• Water and sand (and snow) reflect UV rays, causing extra exposure.

Avoid Tank Tops

• Wear T-shirts or long-sleeved shirts as opposed to lessen exposure of shoulders and sides.

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UV Indexes for Major Cities (Aug. 20, 2012)

CITY STATE UVI Honolulu HI 12 Miami FL 12 San Juan PU 12 Albuquerque NM 11 Los Angeles CA 11 New Orleans LA 11 Houston TX 10 Las Vegas NV 10 Mobile AL 10 Phoenix AZ 10 Charleston WV 9 Dallas TX 9 Denver CO 9 Jackson MS 9 Jacksonville FL 9 Norfolk VA 9 Oklahoma City OK 9 Salt Lake City UT 9 San Francisco CA 9 Tampa FL 9 Atlanta GA 8 Atlantic City NJ 8 Boise ID 8 Cheyenne WY 8 Dover DE 8 Little Rock AR 8 Memphis TN 8 Raleigh NC 8 Wichita KS 8 Baltimore MD 7 Billings MT 7 Bismarck ND 7 Boston MA 7 Burlington VT 7 Charleston SC 7 Chicago IL 7 Cleveland OH 7 Des Moines IA 7 Indianapolis IN 7 Louisville KY 7 New York NY 7 Omaha NE 7 Philadelphia PA 7 Pittsburg PA 7 Portland OR 7 Portland ME 7 Seattle WA 7 Sioux Falls SD 7 St. Louis MO 7 Washington DC 7 Buffalo NY 6 Concord NH 6 Detroit MI 6 Milwaukee WI 6 Minneapolis MN 6 Providence RI 6 Hartford CT 5 Anchorage AK 2 Source: National Weather Service