* WHAT...Strong thunderstorms with organized outflow wind gusts of 45-55 mph will result in blowing dust, reducing visibility between one-quarter mile and one mile at times. Haboob formation is possible. Dense blowing dust will initially develop across southeast Pima and western Santa Cruz counties during the late afternoon and spread west to northwest across the Tohono O'odham Nation and into western Pima and southeast Pinal counties through the evening. Dangerously hot conditions with high temperatures ranging between 103 to 110 degrees and low temperatures 79 to 85 degrees. Major HeatRisk is expected.

* WHERE...Pinal County, Tohono O'odham Nation, Tucson Metro Area, and Western Pima County.

* WHEN...For the Extreme Heat Warning, until 8 PM MST Friday. For the Blowing Dust Advisory, from 3 PM to 10 PM MST Wednesday.

* IMPACTS...Blowing dust can restrict visibilities below a mile posing a significant hazard to motorists. In addition, strong and gusty winds will likely suspend dust into the air that people and animals breathe. Individuals with heart disease and respiratory sensitivities may want to reduce their level of exertion to limit the dust they breathe into their lungs, especially if they are near dust prone locations. Those most at risk may feel better if they avoid outside exercise today, keeping windows and doors closed to help reduce exposure. For the Extreme Heat Warning...heat related illnesses increase significantly during extreme heat events.