* WHAT. Dangerously hot conditions with temperatures between 95 and 105 degrees possible. Low temperatures between 65 to 70 degrees are possible Tuesday night, which would limit overnight relief. * WHERE. Greater Portland/Vancouver Metro, Western and Central Columbia River Gorge, the Corbett area and the Hood River Valley, Lower Columbia River and Cowlitz River Valleys, and Central Willamette Valley. * WHEN. From Tuesday afternoon through Wednesday evening. * IMPACTS. Heat related illnesses increase significantly during extreme heat events. * ADDITIONAL DETAILS. There is a 40-80% chance that Tuesday night low temperatures remain above 65 degrees and a 20-40% they don't drop below 70. There is a 10-30% chance for highs to reach 105 Tuesday and Wednesday across the Willamette Valley, highest on Wednesday.