Through the 19th of July, 2012, Denver, CO has officially recorded 10 days of 100F+ maximum temperatures. The previous year with such heat was 2005, when 7 such days were recorded. Due to Denver’s latitude (~40N) and altitude (~5,200 ft. above sea level), 100F days are rare. This year is developing a series of very anomalous heat and drought observations.
Denver typically experiences 32 90F+ days per year. With most of the summer still to go, Denver has already surpassed that mark. It appears the city is targeting the top-10 90F days in a year. That record is held by 2000 when there were 61 days of 90F maximum temperature or higher. Note that six years since 2000 populate the top-9 list: 2000, 2002, 2005, 2006, 2007, and 2011. There are only four years prior to 2000 in the top-9 (three are tied for 9th): 1994, 1978, 1964, 1960, and 1874. The 9th place years recorded 50 90F days.
So far in 2012, there were 2 90F+ days in May, 17 in June, and 15 so far in July, for a year-to-date total of 34. Denver likely recorded an additional 100F day today and will do the same thing tomorrow. The extended weather forecast doesn’t call for a high less than 90F for the next 7 days. Beyond that, above-average temperatures are forecasted for both the next month and the next 3 months. 90F daily maxima are not unheard of in the first couple weeks of September and I don’t at this point expect conditions to be cooler than that this year.
15 consecutive days were 90F+ from the 22nd of June (102F!) through the 6th of July. If all those records hold up to quality control, that should tie for 7th on the list of most consecutive days with 90F or higher:
2008 JUL 13TH — Aug 5th……24
2011 JUL 15th — AUG 1st……18
1901 JUL 6TH — JUL 23RD…..18
1874 JUL 1ST — JUL 18TH…..18
2000 JUN 29TH — JUL 15TH…..17
1987 JUL 18TH — AUG 2ND…..16
1934 JUL 7TH — JUL 21ST…..15
Notice how the majority of these dates begin in July, not June. Note further that there were three other times when such a streak began within one day of June 22nd (see full list). The reason the streak stopped on the 7th of July was a temporary appearance of North American monsoon moisture that made its way from the Gulf of Mexico around the western periphery of the massive high pressure system that is at the heart of the record setting heat wave and drought afflicting the US this year.
So: will 2012 challenge 2000 for the most 90F days in one year? There are only 16 more days before Denver makes the top-9 list, then 11 more to tie for 1st place. This isn’t a record most of us want to see happen, of course. I would much rather see the monsoon return with a vengeance and alleviate the precipitation deficit under which the area is suffering this year.
Will another noteworthy consecutive 90F streak occur? Denver has 9 in a row through yesterday. With today’s likely 100F, another streak of 10 joins the list. As mentioned earlier, conditions don’t look like they’ll change any time soon. 2012 could see two extended streaks of 90F+. Stay tuned.