What a difference a wind direction makes (H. Michael Mogil, CCM, CBM, DMS)
The other day, I wrote about the arrival of a strong cold front in south Florida. That front arrived with a significant chill down. Low temperature readings, this Saturday morning (Dec. 31, 2016), were in the 40’s across many areas of southwest Florida. Even with relatively light north winds, wind chill readings dipped into the 30’s to the north of a Fort Myers-Lake Okeechobee line. Dew point readings tumbled into the teens and twenties in many areas (Fig. 1).
But, with brilliant sunshine and a wind shift to the southeast, temperatures soared into the 70’s across most of south Florida by mid-day Saturday (Fig. 2) and into the mid- to upper- 70’s across southwest Florida by Saturday afternoon. Of even more significance was that dew point readings jumped from the 20’s into the low and mid 50’s in most places (Naples shown in Fig. 3).
This transition was linked to a change in wind direction. During the day on Friday and into Saturday morning, winds arrived from the north and northeast (Fig. 1); this kept the trajectory of the arriving continental Polar air mass passing over land. On Saturday, the trajectory of air was from water first and over the Florida peninsula next (Fig. 2). The result was that a continental Polar air mass had been replaced quickly by a maritime Tropical one.
And the trend will continue. By today, New Year’s Day, highs across southwest Florida reached the low- to mid- 80’s. Morning lows only dipped into the mid 60’s to lower 70’s along the southeast coast and low 60’s in most other coastal locations. These warmer day- and night- time readings should be the rule (plus or minus a few degrees) for most of the upcoming week.
I hope to be writing, soon, about examples in which wind direction and/or variations in wind direction play a significant role in an evolving weather event. Other GWCC writers have already posted regarding lake effect snow showers and squalls. Stay tuned!
© 2017 H. Michael Mogil
Originally posted 1/1/17