DENVER Colorado is bracing for a historic March heat wave that is likely to shatter records as temperatures push toward 90 degrees by midweek.While Denver experiences one more day of typical March weather on Monday, a powerful jet stream and a strong upper-level ridge are quietly building a heat dome over the state that will drive abnormally warm temperatures Tuesday through Saturday.How unusual are those temperatures? Denver's expected highs in the mid to upper 80s from Tuesday through Saturday are about 30 degrees above normal.The average high temperature for this time of year in Denver is about 55 degrees.The warmest temperature ever recorded for the month in the Mile High City was 84 degrees back on March 26, 1971, and this weeks heat will likely challenge or break that all-time March record.Here is this weeks daily forecast:Tuesday | | 73 | 43Wednesday | | 80 | 45Thursday | | 83 | 49Friday | | 85 | 48Saturday | | 87 | 44By the end of the week, however, relief is in sight: by Sunday, a weak system will move in and cool Denver back to around 70 degrees, which is still well above normal.Colorado is not the only state that will see extreme temperatures.Arizona will see temperatures well into the triple digits for most of the week, much earlier than the region usually sees."This is a heat wave that we have not seen before in recorded history in the Southwest," said AccuWeather meteorologist Dan DePodwin.Phoenix is expected to have five straight days of triple-digit temperatures this week only once before, in 1988, has the city recorded a 100-degree day in March, DePodwin said.DENVER WEATHER LINKS | Hourly forecast | Radars | Traffic | Weather Page | 24/7 Weather StreamThe Associated Press contributed to this report ...read more read less