Oklahoma Gov. Mary Fallin asked residents in her state to pray for rain in response to a devastating heat wave. “I encourage Oklahomans of all faiths to join me this Sunday in offering prayer for rain,” she added, according to Salon.com.

It's only the beginning, shockingly, for this summer's heat wave, which weather officials say will get worse in August, and state heat advisories can't keep up with the sizzling path across the country.

However, health officials in Missouri and Oklahoma began investigating alleged heat-related deaths Wednesday, as Oklahoma expanded its drought emergency statewide. Fallin amended the state of emergency document to include all 77 Oklahoma counties because of ongoing drought. Wednesday was the 30th consecutive day that temperatures topped 100 degrees in Oklahoma City, and Fallin said forecasts show drought conditions are expected to worsen for the entire state.

Oklahoma City's high temperature hit 100 degrees Thursday, July 29th. The record for most 100-degree days in a year is 50, set in 1980, and highs in the 100s are forecast all through the next week.

The sustained heat has taxed local water systems and claimed at least five lives, with another eight deaths possibly being caused by the heat, authorities said. Although, the latest heat-related death was announced Thursday by the state's medical examiner's office. A 25-year-old man in Tulsa, died in June of hyperthermia, a condition caused by excessive body temperature, while he was working at a construction site. The state medical examiner's office added that a 69-year-old man's death in Blackwell on Monday was the state's fourth confirmed heat-related death.

According to the National Weather Service records, the temperature in Ponca City, located near Blackwell, reached 103 Monday.

In Missouri, the Jackson County medical examiner was investigating three possible heat-related deaths, bringing to 13 the number of cases under investigation in the county so far this year. The Kansas City Health Department said the latest deaths are those of a woman born in 1936 and two men born in 1945 and 1964. No other details, including when or where the deaths occurred, were provided.

The National Weather Service has posted an excessive heat warning for most of Missouri until Saturday evening.