WARMER THAN AVERAGE CONDITIONS COULD REDUCE SPREAD OF COVID-19 — Most of the lower 48 states are expecting warmer than average temperatures from now through May. In fact, record high temperatures have been tied or set this week in Southwest Florida including the highest temperature recorded so far in 2020 at Page Field in Fort Myers. The high temperatures rose to 91 degrees Wednesday, March 18th. Naples has also seen its warmest temperature in 2020 twice this week at the Naples Airport. One record was tied and another was set at 90 degrees this week. The high of 90 degrees was also recorded February 18th and 19th of this year at the Naples Airport.
The record strong positive Arctic Oscillation and the strong polar vortex are two important factors in this forecast because they usually result in colder air generally being confined to the polar regions. The Arctic Oscillation is a climate pattern characterized by winds circulating counterclockwise around the Arctic. When the Arctic Oscillation is in a positive phase, it typically correlates with a stronger polar vortex. A strong polar vortex doe not allow cold arctic air to sag into the United States, which in turn keeps things warmer.
This upper level atmospheric pattern combined with a positive Arctic Oscillation and a strong polar vortex has generally been in place all winter long. This has allowed the contiguous United States to experience its warmest winter on record through the end of January. The Arctic Oscillation just reached its highest value on record in early February, and the polar vortex remains very strong as a result.
Forecast models suggest that the vortex should remain strong this spring which means a continued lack of sustained cold air in the United States well into spring. In fact, as spring comes to an end, above-average temperatures are anticipated for most of the contiguous United States.