Today and tonight: .Excessive Heat…This level of heat affects mostly individuals sensitive to heat, especially those without effective cooling and/or adequate hydration. Those extremely sensitive to heat face the highest risk. Some health systems and heat-sensitive industries could be affected. These conditions are most likely across all local islands, the National Weather Service said.
Rip Currents: Life-threatening rip currents are possible in the surf zone, particularly across all local islands. Isolated stronger rip currents may occur elsewhere, especially near piers, jetties, and channels.
Days two through seven (Tuesday through Thursday): Hot conditions will continue due to southeasterly winds and high humidity through the end of the week, promoting high temperatures and high heat indices in the region. Marine conditions will deteriorate by the end of the week as a northerly swell arrives. Beaches will be hazardous along the northern and western coast of Puerto Rico, as well as for St. Thomas and St. John.
Heat Advisory
For Culebra, Vieques, St. Thomas, St. John and adjacent Islands such as St. Croix including Vieques, Christiansted, Frederiksted southeast, Charlotte Amalie East, Charlotte Amalie West, Grove Place, Cruz Bay, Charlotte Amalie, Culebra, Anna`s Retreat, and Frederiksted town.
A Heat Advisory is in effect from 9:00 a.m. this morning to 5:00 p.m. this afternoon, the NWS said.
* WHAT...This level of heat affects mostly individuals sensitive to heat, especially those without effective cooling and/or adequate hydration. Impacts possible in some health system and in heat-sensitive industries.
* WHERE...In Puerto Rico, Culebra and Vieques. In Virgin Islands, St. Croix and St. Thomas, St. John and adjacent Islands.
* WHEN...From 9 AM this morning to 5 PM AST this afternoon.
* IMPACTS...Hot temperatures and high humidity may cause heat illnesses.
Precautionary/preparedness actions
Take extra precautions when outside. Wear lightweight and loose-fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and
heat stroke.
To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat
should be moved to a cool and shaded location. Heat stroke is an emergency! Call 9 1 1.
Tropical weather outlook
[August 20] 8 PM Tropical Weather Outlook Update 
A tropical wave located several hundred miles east of the Leeward Islands is producing a broad area of disorganized showers and thunderstorms. Environmental conditions appear conducive for gradual development of this system, and a tropical depression is likely to form by this weekend while it moves near or to the north of the northern Leeward Islands.
