At the moment of equinox, the Earth’s axis leans neither toward or away from the sun — a parity that produces a nearly equal day and night.
“For us in the Northern Hemisphere, the sun is rising later now, and nightfall comes sooner,” said Deborah Byrd, editor-in-chief of the online magazine Earth and Sky. “We’re enjoying the cooler days of autumn.”
But in South Florida, the onset of fall-like temperatures is still at least a month away.
The average daytime high in West Palm Beach doesn’t dip below 85 degrees until Oct. 20, with overnight lows remaining in the 70s until Oct. 27 when the normal finally dips to 69 degrees.
And even then, the difference between the warmest and coldest periods of the year in South Florida can be just 25 degrees, according to the book Florida Weather, which was co-authored by Florida Climatologist David Zierden.
This week, the difference between the daytime high and overnight low in West Palm Beach was just 12 degrees with Monday reaching a searing 91 degrees and this morning bottoming out at an unofficial 79 degrees.
An area of high pressure over the state should keep the temperatures above normal into the weekend. The normal high this time of year in West Palm Beach is 88 degrees, with a normal overnight low of 75 degrees.
UPDATE 5 p.m.: Hurricane Florence is fighting wind shear that knocked it down to a Category 1 storm with 80 mph winds.
The storm, which just 24 hours ago was a powerful Cat 4, is about 1,050 miles east-southeast of Bermuda and moving northwest at 10 ,m.p.h.
The National Hurricane Center’s 5-day forecast has Florence restrengthening to a Category 3 hurricane early next week.
Forecasters shifted Florence’s track slightly to the south, but cautioned there is a discrepancy in track models after Sunday.
“The uncertainty in this forecast remains larger than normal,” hurricane center forecasters wrote in their 5 p.m. advisory.
While the path of a weakened Florence was still a puzzle Thursday, it’s expected regain Category 3 muscle as it nears Bermuda on Tuesday, putting meteorologists on edge that a powerful hurricane could be off the U.S. east coast late next week.
“It’s going to be a formidable storm,” said Weather Company meteorologist Dale Eck, who is head of forecast operations for the Americas. “We can cross our fingers our fingers and hope it will only be a close call, but it will definitely be some type of threat.”
Hurricane Florence, which roared to a major tropical cyclone on Wednesday, could impact the U.S. coastline this weekend with large ocean swells that forecasters called “life threatening.”
Florence reached Category 4 power briefly Wednesday before easing back to a Category 3. This morning, the storm has maximum sustained winds of 115 mph and is moving northwest at 12 mph. It is about 1,100 miles east-southeast of Bermuda.
Some additional weakening is expected over the next few days as Florence is buffeted by wind shear, but the National Hurricane Center forecast has it restrengthening over the weekend.
Where Florence will go is still a mystery. Forecast models are not in agreement as to the track, which is dependent on an area of high pressure in the central Atlantic that could move more westerly this week with Florence riding underneath of it.
If the high pressure weakens, Florence could be little more than a fish storm heading away from the U.S and out to sea.
“However, if the high pressure area remains strong, then Florence may complete a 3,500-mile-long journey over the Atlantic and be guided right into the U.S. East Coast somewhere from the Carolinas to southern New England sometime during Wednesday or Thursday of next week,” AccuWeather forecasters said.
Behind Florence, the National Hurricane Center is watching two tropical waves it is giving medium to high chances of development over the next 3 to 5 days.
The first wave has been given a 90 percent chance of development and is expected to become a tropical depression by Monday.
The second wave, which will leave Africa tomorrow, has been given a 50 percent chance of development.
The next names on the 2018 storm list are Helene and Isaac.
Florence, currently in the open Atlantic Ocean about 1,250 miles from the Northern Leeward Islands and 1,500 miles from Bermuda, has maximum winds of 100 mph, according to the Hurricane Center. The hurricane is heading northwest at about 12 mph.
Meteorologists at the South Florida Water Management District are predicting the heaviest showers on Monday and Tuesday with some areas seeing between 5 and 10 inches of rain.
“We’re forecasting excessive rainfall. It could be an average over the entire water management district of about two inches but really what that means are there are locations that could receive up to 5 to 10 inches of rain,” said John Mitnik, chief engineer for the South Florida Water Management District.
Mitnik said the district is lowering its primary canal systems in anticipation of larger volumes of water coming from the local water control districts.
Although the rain is expected to be concentrated south of Lake Okeechobee, it affects discharges to the northern estuaries if water conservation areas south of the lake fill up.
The lake was at 14.6 feet above sea level on Thursday, higher than the Army Corps of Engineers prefers it to be during the rainy season when one tropical system could push it quickly into the danger zone.
Last week, the Army Corps of Engineers increased discharges to the St. Lucie Estuary and Caloosahatchee River, saying the lake continued a “dangerous rise” into the peak of hurricane season.
Concerns about the integrity of the aging Herbert Hoover Dike mean the lake is closely monitored during the rainy season, but a record-wet May forced intermittent discharges to begin June 1.
The dike protects Glades-area communities from life-threatening flooding, but can suffer breaches if the water level is too high.
“With continued paramount focus on Herbert Hoover Dike safety throughout 2018, we need to make increased discharges to slow the still dangerous rise in lake levels,” said Col. Jason Kirk, the Corps’ Jacksonville District commander, in a press release.
National Weather Service meteorologists said there is still some question about whether the tropical wave will pass through the Florida Straits or to the north of the straits, which could affect which areas get the heaviest showers.
UPDATE 1:51 p.m.: A tropical wave in the Caribbean was given a 10 percent chance over the next five days of developing into something more by the National Hurricane Center in its 2 p.m. advisory.
Forecasters were already predicting a wet weekend in South Florida from the wave, which could mean a Monday washout with a slight chance of flooding rains.
National Weather Service meteorologist James Thomas said more than 2 inches of rain are possible through Monday, but cautioned that forecast models differ on timing and location with one taking the tropical through the Florida Straits and another moving it north of the Straits.
“There’s a rather wet pattern setting up with the showers and storms coming really at any part of the day,” Thomas said. “I wouldn’t say there will be an overall washout Saturday and Sunday, but that could come Monday and Tuesday.”
Rain chances increase from 40 percent Friday to 50 percent Saturday and 60 percent Monday through Wednesday.
Hazards, including a slight risk for flooding and a moderate risk for rip currents, are expected Sunday through Tuesday. A high risk for lightning is also in the forecast for the same time period.
“If anything it will be Monday and Tuesday we keep our eyes open for flooding,” Thomas said. “Sunday the rain will be more hit or miss.”
If the wave makes it into the Gulf of Mexico, it will have plenty of warm water to “feast on,” said Jeff Masters, co-founder of Weather Underground.
At 86 degrees, the Gulf is running 1.8 degrees warmer than normal.
“The total amount of heat energy in the Gulf right now is at near-record levels for this time of year – similar to last year’s levels, and much higher than observed during the awful hurricane season of 2005,” Master’s wrote in his Cat 6 blog.
UPDATE 10:52 a.m.: The National Hurricane Center is issuing advisories on Potential Tropical Cyclone 6, which is forecast to strengthen to Tropical Storm Florence and then a hurricane by Sunday.
It would be the third hurricane of the 2018 season, following Beryl and Chris.
The potential tropical cyclone is in the far eastern Atlantic, about 425 miles east-southeast of the Cabo Verde Islands with maximum sustained winds of 30 mph.
UPDATE 10:15 a.m.: The National Hurricane Center said it will begin issuing advisories for Potential Tropical Cyclone Six at 11 a.m. The bundle of showers and thunderstorms is east-southeast of the Cabo Verde Islands.
The center started identifying “potential tropical cyclones” in 2017 so it could issue advisories to people before the system actually forms.
Previous story: A strong tropical wave about to hit the main development region of the Atlantic basin has a 90 percent chance of development over the next five days, and is likely to become a depression or tropical storm by the weekend.
The system would be named Florence if it becomes a tropical storm.
Sea surface temperatures have warmed from their unseasonably cooler status earlier this year and the dry Saharan air, which is known to discourage tropical development, is north of where this system is about to emerge.
“All of the models show some development of this wave in the waters near the Cabo Verde Islands off the coast of Africa as early as Saturday,” said Weather Underground co-founder Jeff Masters in his Cat 6 blog.
Of more immediate concern to South Florida is whether Labor Day weekend will be a washout.
The NHC is showing no tropical development near Florida over the next five days, but a tropical wave near Puerto Rico will be making its way west late this week.
Masters is predicting a tropical depression to form early next week in Florida waters, but he said anything that forms has a better chance of doing so in the Gulf of Mexico, affecting the west coast of the state. But he notes that none of the major weather models predicted the wave to develop into a cyclone by Saturday.
The National Weather Service in Miami said models differ on location, timing and rain chances with the wave’s arrival still a few days away. But a strong tropical wave would “more directly impact the region with precipitation chances that could be enhanced just about any time of the day.”
The shower gets going in South Florida as the constellation Perseus comes up over the northeastern horizon, which is about 11 p.m., said J. Kelly Beatty, senior editor for Sky and Telescope.
“The very early ones are skimming through the atmosphere and can create really dramatic fireballs,” Beatty said. “If you are looking from a very dark site, like the middle of the Everglades, you might see one every minute, but if not, it might be one every 10 to 15 minutes.”
The best viewing conditions — generally a dark area away from the city lights — can be hard to come by in South Florida, but a drive to Lake Okeechobee or even a stroll on the beach may suffice. Also, the website Slooh will live webcast the shower to its members beginning at 5 p.m. Sunday. Memberships are available at Slooh.com.
The Perseid shower is considered runner-up in quantity and brilliance only to the Geminid shower in December, and is known for being fairly rich in fireballs. Fireballs are brighter than the planet Venus.
A NASA analysis of all-sky images taken from 2008 to 2013 shows that the Perseids deliver more bright meteors than any other annual meteor shower, according to Sky & Telescope.
Debris from the comet 109P/Swift-Tuttle is the source of the Perseids. The comet orbits the sun in a large cigar-shaped motion, with Earth passing through the comet rubble every year in mid-August.
The comet sheds debris that can range from the size of a pinhead to a half-dollar.
“The moonless sky this year means the viewing will be excellent, and the shower’s predicted peak is timed especially well for North America,” said Sky & Telescope Observing Editor Diana Hannikainen in a press release. “Under a very dark sky, you might see up to one Perseid per minute late on Sunday night or after midnight on Monday morning.”
Whether South Florida’s skies will cooperate with viewing the Perseids is in question.
After a bout of Saharan air dried out the atmosphere mid-week, showers were expected to return Friday afternoon and extend through the weekend in a more typical summer pattern.
The National Weather Service in Miami is forecasting a 30 percent chance of rains today and tonight for much of Palm Beach County with a daytime high temperature of 91. The heat index, or “feels like” temperature could hit 103 today.
Sunday also has a 30 percent chance of showers with the possibility of thunderstorms. The high temperature Sunday should be in the high 80s to low 90s.
Confidence that 2018 will experience a below normal hurricane season increased substantially this week as global forces align to temper tropical activity.
An updated forecast released Thursday by the federal Climate Prediction Center is now calling for a 60 percent chance of a less active storm season, a hefty jump from a May forecast that predicted only a 25 percent probability of below normal activity.
Gerry Bell, the center’s lead seasonal hurricane forecaster, said the growing likelihood that a storm-thwarting El Nino will form in the fall combined with tropical Atlantic water temperatures that are the coldest since the 1990s were key factors in making the new prediction.
The forecast comes as Florida enters the peak of hurricane season between mid-August through October when 95 percent of hurricanes form. Already four named storms – Alberto, Beryl, Chris and Debby – have spun up this season. Beryl and Chris both mustered hurricane strength.
As of Thursday afternoon, Tropical Storm Debby was still churning harmlessly in the northern Atlantic.
And hurricane experts warned Thursday there will be more storms.
“It’s not dead,” said Stanley Goldenberg, a meteorologist with the Hurricane Research Division of the National Oceanic and Atmospheric Administration. “Storms can pop up quickly and we do expect more storms.”
The hyperactive 2017 storm season produced 17 named storms, 10 hurricanes and six major hurricanes.
Bell said when the May forecast was released the chances an El Nino would form were only 45 percent.
An update this week puts the odds of an El Nino forming in the fall at 65 percent and up to 70 percent of a winter El Nino that could last into 2019. Bell compared this season to 2015, which had 11 named storms and 4 hurricanes.
“Please remember the hurricane seasonal outlooks are a general guide and do not predict landfalling storms,” Bell said. “Whether or not a storm strikes land is determined by the weather patterns in place when the storm approaches and those are generally not predictable until five to seven days in advance.”
Earth was put on an El Niño watch in June, but it’s not officially declared present until ocean temperatures in the equatorial Pacific are more than 1 degree above normal and are expected to maintain that temperature for six months.
After that, it can take 30 to 60 days for the atmosphere to respond.
The onset of El Niño occurs in tandem with the relaxation of the trade winds — those Earth-skimming easterlies that have guided sailing ships across the world’s oceans for centuries.
With the trade winds reduced, warm water that has piled up in the western Pacific Ocean and around Indonesia rushes back toward the east. That movement of warm water shifts rainfall patterns and the formation of deep tropical thunderstorms. The exploding storms whose cloud tops can touch the jet stream disrupt upper air patterns so winds come more out of the west.
The west winds create shear in the Atlantic, which can be deadly to budding hurricanes.
“The main message should be that no matter what this or any other prediction says that people must treat this like the peak of hurricane season and be prepared,” Goldenberg said. “Remember, 1992 was overall a very slow year.”
Category 5 Hurricane Andrew – the first named storm of the 1992 season – devastated areas of South Florida when made landfall Aug. 24.
At least 20 research groups, private companies and universities churn out annual hurricane forecasts, including the University of Arizona, The Weather Co. and Pennsylvania State University’s Earth System Science Center.
CSU is predicting nine more named storms through November, three hurricanes, and one major hurricane of Category 3 or higher. Today’s forecast does not include sub-tropical storm Alberto, or hurricanes Beryl and Chris.
A normal season has 12 named storms, six hurricanes and three major hurricanes.
South Florida’s beaches faced a sargassum assault this summer that some scientists believe is part of the largest spread of the nomadic marine weed on record, and one that could continue through September.
From the Keys through the Treasure Coast, islands of the brown algae floating on berry-like bladders have stained beaches and sailed through inlets thick enough that one Palm Beach County lifeguard saw a black racer snake drift by on one large mat.
While a reprieve may be underway locally, county officials report two waves of sargassum have swept ashore since May, with no guarantee another surge isn’t lurking.
In June, sargassum spread through 1,158 square miles of the Caribbean Sea. That’s three times the sargassum coverage during the same time in the record-high year of 2015.
“Right now there is still a lot of sargassum in the Caribbean, so I think these events will last for a while,” said Mengqiu Wang, a researcher at the University of South Florida’s Optical Oceanography Laboratory, which has tracked sargassum since 2000. “There still could be a high chance the sargassum could show up again in Florida.”
As unpleasant as it may be, the smaller manatee is trying to mate with the dead one, which is tethered to the dock so that the Florida Fish and Wildlife Conservation Commission can pick it up to perform a necropsy.
“It is not uncommon for male manatees to do this, as the female still has an attractive scent to them, even after she has passed away,” deWit said.
Baby manatee clinging to its dead mother – this is a result of the water releases from Lake O. Do we want Rick Scott to have 6 more years in office? Elect people to Congress that care about Florida's environment, people, and economy. #ToddJTruaxforCongresspic.twitter.com/InxmayYWCp
FLORIDA ALGAE CRISIS: This heartbreaking image shows a baby manatee clinging to its dead mother. Her death appears to have been caused by toxic algae in the water near the Cape Coral Yacht Club. Toxic blue green algae is impacting large swaths of Florida. Photo: Niki Padilla. pic.twitter.com/FdyG98k2MK
This year, 484 manatees have died in Florida through July 20.
That’s the highest number for this time of year since 2013 when 694 manatees died through mid-July. By the end of 2013, more than 800 manatees were dead, topping the previous record of 766 set in 2010 during a lengthy cold snap.
Just eight of the deaths were in Palm Beach County, with half related to boats or other human interactions. By far the highest number if manatee deaths were in Lee County where 109 died, 52 of which were ruled natural. Red tide-related deaths are categorized as natural.