The furnace is on 'high' through the weekend in southern areas of Texas. Excessive Heat Warnings include Brownsville and areas along the Mexican Border, with a Heat Advisory northward to Corpus Christi. With high humidity and hot temperatures near 100 degrees, the heat index will surge through the triple digits and above 110 degrees in the warning areas.   https://twitter.com/NWSBrownsville/status/1136949173335613440 The combination of hot temperatures and high humidity will combine to create a situation in which heat illnesses are possible. Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Take extra precautions, if you work or spend time outside. When possible, reschedule strenuous activities to early morning or evening. Know the signs and symptoms of heat exhaustion and heat stroke. Wear light weight and loose fitting clothing when possible and drink plenty of water.   https://twitter.com/NWSBrownsville/status/1136943387209359360 The heat will build across the Southwest next week. An Excessive Heat Watch has already been issued in south central and southwestern Arizona, including Phoenix. Temperatures are expected to hit around 110 degrees on Tuesday and Wednesday, with lows near 80.   Heat sensitive people and those who are slow to acclimate to meteorological summer will be most prone to heat illness. Dehydration and prolonged exposure or strenuous physical activity outdoors during the hottest time of the day could lead to heat exhaustion and/or heat stroke. If you have to be outside this afternoon, wear sunscreen, drink plenty of water, and wear light colored, loose fitting clothing.   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.