May is no stranger to wild temperature swings, and we are once again experiencing one this year. Less than two weeks ago, several nights fell to frost and freeze levels as we put together a stretch of below normal days that lasted two weeks.
Last May produced the coldest temperature on record when we fell to 27° the morning of the 9th, decimating early spring flowers that had already budded. However, it turned warm quickly, and much like this year, ended with very warm weather. Sixteen days later, we set the month’s high of 88°. May 2020 was among the top three largest temperature spreads within the month on record.
The long advertised pattern change has taken effect, and Thursday warmed to 83° in Indianapolis. This was the warmest of 2021, surpassing April 27’s 82° high, and the normal high for June 18.
Before the pattern change, this May ranked among the 13 coolest on record, and this year has produced the least number of 80-degree days in 15 years. As of May 17, the average temperature for the month was a whopping 6° per day below normal. That is over.
We have had a serious overhaul of the upper level winds — the jet stream — that includes a large surge of colder air deep into the western U.S. The resulting “dig” buckles the jet stream north in the eastern half of the nation.
Warm air has now flooded the once quite chilly eastern U.S., and soon a new feature will emerge. A large, upper-level high pressure will form and expand in more typical summer fashion over the southeast U.S. entering the weekend, and that will aid in sending temperatures even higher.
The sinking air and the expanding bubble of high pressure precludes clouds from building to produce rain and the air warms. This expanding HOT DOME will bring area temperatures to near 90-degrees this weekend. Sunday will likely be the warmest with the most sunshine in the forecast and an official forecast of 89°. Many locations could reach 90-degrees this weekend. We will be monitoring.
Showers and thunderstorms look to hold off for several more days and may not really become a threat until next Wednesday.