Lower dew points have arrived in southwest Florida. For the past two and a half days, dew point temperatures at Regional Southwest Airport (RSW) in Fort Myers have remained in the comfortable 50’s. That’s a stark contrast to the lower 70’s, where dew points hovered earlier in the week. Along with the dew point drop, daytime temperatures remained in the 70’s on Thursday and only reached the lower 80’s on Friday.
For most, the difference in sensible air temperature can best be summarized by saying, “ahh!” Still, there was a chill in the air, especially early in the day. Some people were actually wearing sweaters and sweat shirts.
Another factor that helped to keep daytime temperatures lower was the cloud cover. On Thursday, skies were laden with several layers of mid- and high- level clouds. At best, a faint sun tried, unsuccessfully, to brighten the sky. Friday saw fewer cloud layers and they weren’t as thick. Hence, the sun made its presence felt throughout the day.
These clouds were linked to a strong sub-tropical (low-latitude), west to east, jet stream at 30,000 to 40,000 feet above ground level. When coupled with near ground level winds from the northeast, this vertical wind pattern is often associated with extensive cirrus (high-level) and altocumulus (mid-level) clouds. The more extensive and thicker cloud pattern is typically found on the side of the jet stream closest to the Equator.
Early this Saturday morning (Oct. 26, 2013), the jet stream and its associated cloudiness remained in place across south Florida (Fig. 1). Computer models hold the jet stream across northern and central Florida until at least Sunday (Oct. 27, 2013) afternoon. Then the jet stream weakens and upper level winds begin their turn to northerly. Meanwhile, near the ground, steady east and northeast winds will continue, gradually leading to higher temperatures and dew points and more low-level, mainly afternoon, cloudiness. Winds will be stronger and gustier over offshore south Florida waters, where small craft advisories are in place.
By Monday, dew points temperatures will rise into the mid 60’s. Temperatures will warm into the mid- and then upper 80’s as the new workweek unfolds. For many, it will be time to turn on the air conditioning again.
Meanwhile, the protracted return to dry weather across southwest Florida will continue into the foreseeable future. Already, the wildfire danger has risen to the moderate category across southwest Florida. Across some parts of north Florida, the Fire Danger Index is already in the high to very high category. Since the National Weather Service is looking for a drier than average “dry season” across southwest Florida, look for fire danger values across Collier and Lee Counties to rise over the next few weeks and next few months.
© 2013 H. Michael Mogil