Happy New Year!
It was mainly partly cloudy overnight (except for the well inland areas where it was clear). There was a wide variation of temperatures. At approximately 7:30 this morning, Boca Raton, Florida had a temperature of 68 degrees while a reporting site Arther R. Marshall Loxahatchee National Wildlife Refuge had a temperature of 48 degrees. Below are other observations across south Florida (source from WunderMap).
The wide variation in temperatures was due to the cloud cover and winds. The clouds and winds (warmer waters of the Atlantic Ocean) prevented the temperatures from dropping much along the east coastal sections.
The overnight temperatures were generally in the 50’s to middle 60’s. Winds already had veered to the east at 10 – 20 mph (lighter winds further inland).
During the day, it was a generally partly cloudy day to occasionally cloudy (mainly along the coast). Highs were uniformly in the low 70’s to upper 70’s. Winds were diminishing and the small craft advisory was dropped this morning. Winds were also veering to the southeast.
The lows tonight will be mainly in the 60’s (it may get close to 70 along the coast). There may be some 50’s further inland.
The warm-up will continue into New Years Day with generally partly sunny/partly cloudy skies. With the winds veering to the southeast and south, moisture will increase a bit. Highs will be around middle 70’s to low 80’s. Lows will be generally in the 60’s to around 70 along the coast. Again, there may be some 50’s further inland. Winds will have diminished and be more in the 5 – 15 mph range from the southeast veering to the south. Boating conditions will have improved with waves of 2 – 5 feet with a moderate chop.
On Wednesday, the skies will be partly sunny/partly cloudy. Highs will be upper 70’s to low 80’s. Lows will be in the 60’s to 70. Winds will generally be from the southeast and south at 5 – 10 mph. Wave heights at around 2 feet with a light chop.
On Wednesday night/Thursday, a front will move into north Florida and move very slow southward. By later Thursday/Thursday night, the front will be closer and with moisture in place, it may be enough to generate some showers/slight chance of thundershower activity. It will be generally partly cloudy. Highs will be upper 70’s to middle 80’s. Lows will generally be in the 60’s. Winds will be out of the south, veering southwest at 5 – 15 mph. Seas will be around 2 feet with waters a light chop.
Friday will become mostly cloudy as the front inches closer to the area. The front may clear southeast Florida later on Friday. The chance of showers and slight chance of thundershowers will continue. Highs will be in the upper 70’s to middle 80’s. Lows will range in the 60’s. Winds will be out of the southwest at 5 – 15 mph. Seas will be 2 – 5 feet. Depending on the location of the front, winds will shift to the north to northeast and increase. After frontal passage, winds will increase to 10 – 20 mph.
There is some uncertainty on the movement and timing of this frontal system as it moves generally southward. The temperatures, clouds, showers and winds may need to have adjustments made accordingly. There will not be a drastic cool down. By the time the front makes it into southeast Florida, the high will have moved far enough east that the winds will have already turned to the northeast. Also in looking at the forecast models, there may be a breezy/windy period after frontal passage. If this verifies, boating conditions will deteriorate.
As mentioned yesterday, there is a robust upper level high over southern Bahamas/northern Caribbean. Notice all that dry air (brown color) surrounding this high. There is a rough drawing of the upper level flow around the high.
This high will temporarily weaken and move away a little. After the upper level trough moves away, forecast models has this high rebuilding, expand and move closer the southeast U.S. coast. This will lead to warmer weather and less frequent frontal passages (if any). Winter may disappear for a while in south Florida.
Of interest is that there is something called the NAO (North Atlantic Oscillation). This index measures the difference of pressures between the Subpolar low and the Azores High. These differences of pressures effect the wind flow across the northern hemisphere. A positive NAO tends to have warmer weather over the eastern U.S. and a negative NAO conversely tends to have colder temperatures over the eastern U.S. The CPC (Climate Prediction Center) has a good explanation of this index and its effects. There is also additional information here on the NAO index. This index is only good as a predictor for about two weeks in advance. Of course, there are other factors that could effect temperatures/weather. For the past few weeks, the NAO index has been rising.
The forecast models has the NAO index decreasing toward the end of January.