Winter is Coming (H. Michael Mogil, CCM, CBM, NWA-DS*)
For this article, I’m stealing a line from “Game of Thrones” – “WINTER IS COMING!”
December 1 marked the start of meteorological winter (meteorologists define the months of December, January, and February as being winter); astronomical winter starts about three weeks later (when the earth, in its orbit around the Sun, is at position when Northern and Southern Hemispheres each receive about 12 hours of sunlight daily).
December 1 was also a day after snow fell across a large part of the Ohio Valley. Early on December 1, about 13% of the U.S. was snow-covered (Fig. 1) according to NOAA’s National Operational Hydrologic Remote Sensing Center (NOHRSC).
The storm system responsible for this snowfall event set the stage for a reversal of weather conditions in many parts of the Nation, including southwest Florida (my focus here).
During November, temperatures in Naples averaged about 5 to 6 degrees above seasonal average. Come December 1, temperatures tumbled in our area thanks to the passage of a strong cold front. That was followed about a week later by strong cold front number two. Both fronts allowed 
much colder air to infiltrate into south Florida; the colder air mass behind each front kept daytime highs in the 60’s to low 70’s and overnight lows in the 40’s for several calendar days in a row. For the first 14 days in December, daily temperatures have averaged about four degrees below average and have only been above average on five days (Fig. 2).
Yesterday (December 14), a weak cold front affected our area, but didn’t greatly change our temperatures. However, another, stronger cold front (blue line with triangles marking the direction toward which the front is moving) is on our immediate horizon, and is expected to arrive early this Thursday (Fig. 3). Computer models show that there are other cold fronts looming for the latter part of December. Each of these will be linked to a mid-Atlantic to New England snow event. So, anyone planning to travel to the northeast U.S. the next few weeks should take note.
Under any circumstances, dew point temperatures (that pesky measure of comfort or discomfort) in our area will remain mostly on the low side. Even when rising into the upper 60’s for a few days, weather conditions shouldn’t be “oppressive.”
As we usually say here in southwest Florida, the months of November to April (our 6 months of “winter) make up for summer’s often unbearable heat and humidity. Although COVID-19 still has us in its clutches, the weather is offering us a great excuse to sit on our lanais, take a walk, or party (socially-distanced, of course) with neighbors on our driveways. Enjoy this weather now because “SUMMER IS COMING, SOON!”
© 2020 H. Michael Mogil
Originally posted 12/15/20
* The National Weather Association Digital Seal (NWA-DS) is awarded to individuals who pass stringent meteorological testing and evaluation of written weather content. H. Michael Mogil was awarded the second such seal and is a strong advocate for its use by weather bloggers.