Forecasters in Florida see possible shift to drier pattern

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UPDATE: The tropical wave in the Central Atlantic was designated Invest 92L by the National Hurricane Center. It was plotted at 5N 33.3W, about a thousand miles southwest of the Cape Verde Islands and 3,400 miles east-southeast of Miami. Early forecast models showed the system just clearing the northern coast of South America and moving northwest in the Caribbean. The eastern Caribbean is often a graveyard for Cape Verde storms, but early intensity models show 92L achieving and maintaining tropical storm strength through five days. (Image credit: SFWMD)

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Two areas of disturbed weather were upgraded Friday by the National Hurricane Center. (Credit: NHC)

Weather warning: A pattern shift may be dead ahead.

Forecasts for next week’s tropical weather are trending far enough west that Florida may be out of the picture for any significant rainfall. In fact, as we head toward July a typically drier pattern may be setting up, the National Weather Service says.

Normal July rainfall drops off in a major way from average June precipitation, falling from 8.3 inches to 5.76 inches in West Palm Beach and from 9.67 inches to 6.5 inches in Miami.

So climatology suggests that we may be moving toward a drier summer period.

Last year, July was uncommonly dry, with Palm Beach International Airport recording just 1.59 inches of rain and Miami, 4.11 inches.

That was particularly bad news since July 2016 was the hottest on record.

The Climate Prediction Center is noncommittal for July rainfall, predicting above-normal precipitation for the northern Gulf Coast while shrugging off most of the rest of the country. There’s a big question mark over the Florida peninsula, and rainfall totals will probably depend in part on how active the tropics will be next month.

As for the two systems on the National Hurricane Center map currently, both earned upgrades overnight. The Low that is progged to form over the Yucatan was given a 60 percent chance of tropical development by early next week, and the Atlantic wave that rolled off the coast of Africa on Monday was upgraded to 40 percent over five days.

The next two names on the Atlantic list are Bret and Cindy. And although the Central Atlantic wave appears to be getting better organized, the NHC track suggests it might crash-land into South America before it has a chance to cause any mischief in the Caribbean.

It is slightly disturbing, for non-meterological reasons, that the names for the 2017 hurricane season are recycled from 2005, although there were a number of retired names that year so instead of Katrina, there’s Katia; and instead of Rita there’s Rina; and instead of Wilma there’s Whitney.

These names were used in 2011 as well, and that season was no slouch with 19 named storms, seven hurricanes and four majors.

July was quite active that year with three tropical storms, and then things got crazy in August with seven named storms forming in the Atlantic, including Category 3 Hurricane Irene.

Fortunately, names are just names and have nothing to do with environmental conditions over any given year.

We hope.

Chances of tropical system in Gulf are increasing, Hurricane Center says

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National Hurricane Center forecasters got out their orange marker for the Yucatan Peninsula on Thursday, showing increased odds for tropical development. (Credit: NHC)

A tropical storm or depression is looking more likely in the Gulf of Mexico next week after the National Hurricane Center bumped up chances for development.

Forecasters said there’s a 50 percent chance that a low expected to spin up near the Yucatan Peninsula will become a tropical depression, or Tropical Storm Bret, by Tuesday.

NOAA’s GFS and the European model (ECMWF) are in agreement with development, and eventually take the system into Mexico, while the Canadian (CMC) and the Navy model (NAVGEM) push a deeper low up through the Central Gulf of Mexico toward the western Florida panhandle.

But since the GFS and ECMWF are the gold standards in weather forecasting, local National Weather Service are basing their longer-term forecasts on the western scenario, which will likely mean less rain for Florida’s East Coast next week.

The eastern Atlantic tropical wave, meanwhile, still has a 20 percent chance of developing by Tuesday, the NHC said. But it’s interesting to note that several other potent waves are emerging off the coast of Africa behind the one posted on the NHC forecast map — very early, indeed, for such a parade to begin.

However, wind shear analyses by the University of Wisconsin continue to show hostile conditions in the Central Atlantic, with shear ranging from 25-50 knots. Ditto for the western Caribbean, although conditions become a bit more marginal in the Gulf of Mexico, and shear is forecast to drop in the southwestern Gulf on Friday.

It’s also interesting to note that neither area of projected development has been designated an invest yet by the NHC, which means the full range of model maps is not yet available. For the western Caribbean, that could change later on Thursday or Friday, since storms seem to be boiling up with more frequency off the coast of Central America.

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OUT WITH DROUGHT: Florida’s wet June has really done a number on drought conditions that had built up over the dry spring. Thursday’s report by the U.S. Drought Monitor showed drought-free conditions in all of South Florida with Moderate Drought still in place in Central Florida from Tampa to Brevard County on the East Coast.

That could be wiped away next week if any of the tropical moisture from the Gulf makes its way into the Tampa area.

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SNEAK PEEK AT EARLY FALL: NOAA’s Climate Prediction Center released its 90-day forecasts Thursday, indicating above-normal temperatures across almost all of the U.S. through September. Forecasters hedged their bets on precipitation forecasts, indicating equal chances for above- or below-normal rainfall across most of the country with the exception of the northwestern Gulf coast, where abnormally high precipitation is forecast.

Normal rainfall is expected in South Florida through the end of June.

Two areas being watched by Hurricane Center as season revs up

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The Tropical Weather Outlook map is unusually active for mid-June, with two areas in the Atlantic being monitored. (Credit: NHC)

A strong tropical wave in the eastern Atlantic — unusual for this time of the year — has grabbed the attention of the National Hurricane Center where forecasters were giving it a 20 percent chance of development by Monday.

NHC forecast maps suggest that this could be a long-tracking system more typical of the type seen in August and September, during the peak of the Cape Verde season (see historical note below).

An area of disturbed weather around the Yucatan Peninsula was also given a 20 percent chance of development over the next five days as it moves north into the Gulf of Mexico.

While forecast models haven’t really grabbed on to the eastern Atlantic wave, they continue to predict something coming out of the Yucatan/ western Caribbean by late this weekend. Wednesday’s runs of GFS had a very weak low meandering in the Bay of Campeche, but the European (ECMWF) aimed it at South Texas.

The Canadian and Navy models suggest some development farther to the east, near the western tip of Cuba or off Florida’s West Coast.

National Weather Service forecasters in Miami said in their Wednesday analysis: “Looking into the beginning of next week, both the GFS and the ECMWF have a tropical low moving off the Yucatan, and progressing to the northwest. However, the models are indicating it could spread some additional tropical moisture across South Florida for Monday and Tuesday ….”

Whatever develops “will bear close watching over the next several days,” they said.

NOAA’s Weather Prediction Center is forecasting the heaviest rainfall over the next seven days for the Florida peninsula, with more than 3 inches from Tampa to Key West.

In Texas, National Weather Service forecasters in Houston noted the ECMWF forecast for South Texas, predicting a land-falling tropical storm or depression for Matagorda Bay near Port O’Connor. Wednesday’s run of the European may be “more of a fluke,” they said, “but it does serve as a reminder to ensure that all our hurricane plans and
kits are refreshed and ready to go.”

RECORD WATCH: West Palm Beach and Melbourne each tied record warm lows on Monday — 81 in West Palm Beach and 78 in Melbourne.

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The track of Tropical Storm Ana in 1979. It developed from a tropical wave that exited the coast of Africa on June 14 and was named a depression on June 19 . The system was upgraded to a tropical storm on June 22. (Credit: Wikimedia Commons)

HISTORICAL NOTE: Tropical development in the deep Atlantic is so rare in June that only two tropical storms have been recorded since 1851 prior to July 1, Weather Underground’s Bob Henson said in a blog post Wednesday afternoon. They are Tropical Storm Ana in 1979, and the 1933 Trinidad hurricane.

Hurricane Center watching Caribbean for possible development this weekend

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There’s a 20 percent chance of a disturbance developing into a depression or tropical storm off the Yucatan by Sunday, forecasters say. (Credit: NHC)

Forecast models have been predicting tropical development off the Yucatan Peninsula for the past few days — and now the National Hurricane Center is watching the area closely.

The agency said in its Tropical Weather Outlook Tuesday that whatever develops — if anything — will move northwest over the peninsula and into the southeastern Gulf of Mexico. A tropical depression — or the second named storm of the Atlantic season, Bret — could form over the Bay of Campeche early next week.

The northwestern Caribbean and the southern Gulf of Mexico are typical areas for tropical development in June.

Not so typical for June is development in the tropical Atlantic. That’s something that normally begins to occur in late July or early August, with the start of the Cape Verde season.

There have been several tropical waves over the past week lined up to roll off the coast of Africa, however, including a robust wave that showed up on satellite in the far eastern Atlantic.

Here’s what it looked like on Tuesday afternoon:

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A very healthy tropical wave was in the far eastern Atlantic on Tuesday. (Credit: NOAA)

 

 

 

 

Balmy Atlantic waters bring record warm nights to South Florida

Low temperature records were set or tied at all three major South Florida reporting sites on Sunday as easterly winds blew into the peninsula off exceptionally warm water.

Sea surface temperatures in what’s known as the Main Development Region during hurricane season are running up to 2 degrees or more Celsius (3.6 F) above average, all the way from the West Coast of Africa into the Central Atlantic and Caribbean.

If these trends continue all summer the effect on developing tropical systems in the Atlantic, particularly during the August-September Cape Verde season, would be troubling. The immediate impact is ultra-balmy nights on Florida’s East Coast.

Miami’s low on Sunday was 82, which easily busted the previous record warm low of 80 set in 2010. It was 79 in West Palm Beach and 78 in Naples, both tying record warm lows.

Monday’s apparent low in West Palm Beach was 81 with a dew point of 75, creating an early morning heat index of 87 for anyone choosing to have their coffee on the patio. Winds were rustling out of the east at 8 mph.

If it holds, the 81-degree low at Palm Beach International Airport would be good enough to tie the record warm low set in 2015.

Apparent lows were 82 in Miami and 81 in Fort Lauderdale. It was 78 in Naples.

With sunshine returning to South Florida on Sunday, the heat index popped over 100 degrees in Miami while it topped out at 95 in West Palm Beach.

Sunday was the first day without any rain at all in West Palm Beach since June 1. Fort Lauderdale reported no precipitation and Miami and Naples each had a trace.

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Water temperatures in the Atlantic are running significantly above average with the start of the hurricane season. (Credit: NOAA/ NESDIS)

Speaking of sea surface temperatures: The only cool water in the latest satellite observation data was in the northern Gulf of Mexico, which could inhibit tropical development forecast by some computer models next week.

On the other hand, AccuWeather said Monday that wind shear in the Gulf may ease off next week, creating a more favorable environment for a tropical system.

The National Weather Service in Miami was also weighing the possibility of a disturbance in the western Caribbean this weekend, which would initiate another round of heavier rainfall for Florida.

Projected seven-day precipitation totals over the peninsula by NOAA’s Weather Prediction Center range from 2-3 inches in Central and South Florida.

Tropical development could spur another soaking for Florida peninsula

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The third tropical depression of the season formed in the northeastern Pacific on Sunday afternoon, the National Hurricane Center said. It was forecast to top out as a minimal tropical storm  — Calvin — on Tuesday before coming ashore in Mexico. (Credit: NHC)

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The drier weather that moved in after last week’s drenching of the Florida peninsula may come to a soggy end late this week and into next weekend, long-term forecasts suggest.

Forecast model scenarios suggesting tropical development are starting to get some attention from the National Weather Service. And Miami forecasters say whatever bubbles up out of the Caribbean next week could bring another period of more concentrated rainfall over the area.

“The GFS and ECMWF both indicate a potential disturbance moving northward in the western Caribbean sometime this weekend,” they said Sunday. “Regardless of its evolution, this feature should advect deeper tropical moisture towards South Florida. If this is the case, expect wetter than normal conditions to return to South Florida.”

Since the models describe scenarios in the seven- to 10-day time frame, there’s plenty of room for debate over the type of system that develops — or whether anything develops at all.

While the eastern half of the Gulf of Mexico had plenty of convection on Sunday, the Caribbean was dead quiet, with the exception of the southern Caribbean off the coast of Central America.

Wind shear maps issued by the University of Wisconsin put the Gulf firmly in the “red zone” — too high for tropical development. Ditto for the northwestern Caribbean.

The Houston National Weather Service office said Sunday morning: “Overall there will be too much shear across the Gulf of Mexico for any tropical development for the next 7 days. While this needs to be filed in that ‘nothing to see here’ category, we will continue to monitor model ‘canes’ that the models are forming in the day 7 to 10 time frame.

“GFS now has some type of system in the Gulf headed towards Tampico Mexico. The ECMWF/CMC develop this same wave over the Yucatan except take the system towards Florida, ECMWF much slower than the CMC. Again, these are model systems in the far extended forecast and usually do not materialize.”

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Above: Points of origin for late June tropical storms and hurricanes. Below: Typical June storms tracks. (Credit: National Hurricane Center)

June tracksThe Atlantic hurricane season runs from June 1 to November 30, but historically June and July are pretty quiet. On average from 1966 to 2009, the first named storm doesn’t form until July 9, and the second doesn’t show up until August 1. The first hurricane normally appears on August 10.

The busiest month for tropical cyclones, based on NOAA data from 1851 to 2015, is September — 578 formed during that month, compared with 383 in August and 118 in July. Only 90 tropical cyclones have formed in June over that 164-year period, according to NOAA.

Last year was quite busy in June, however. There were three named storms — Tropical Storm Bonnie (May 27-June 4); Tropical Storm Colin (June 5-7); and Tropical Storm Danielle (June 19-21). After that impressive run, there wasn’t another named storm in the Atlantic until August 2.

The last June hurricane was Hurricane Chris in 2012. It peaked at 85 mph.

Rain in Florida’s weekend outlook, but no wash-out; forecast models weigh late-June tropical activity

7 day rainfall totals

Seven-day rainfall totals through Friday morning show near 20 inches of rain have fallen in parts of South Florida. (Credit: NWS-Miami)

SATURDAY UPDATE: With the 1.96 inches of rain that fell at Palm Beach International Airport on Friday, West Palm Beach has already surpassed normal rainfall for the entire month of June at 8.74 inches. The normal for the month is 8.3 inches.

Ditto for Miami, which has had almost 11 inches and Fort Lauderdale, which has logged almost 10 inches. Naples has had 5.41 inches, which is 61 percent of normal rainfall for the whole month.

Central Florida, from Tampa to Sarasota and from Daytona Beach to Fort Pierce, is also enjoying significant precipitation surpluses, as are the Florida Keys.

SATURDAY LOOK AT TROPICS: All of the major forecast models have hopped on to the idea of tropical development next weekend somewhere around the Yucatan Peninsula. The GFS, the Canadian (CMC) and the Navy model (NAVGEM) have the system spinning up in the Caribbean and then moving north into the Gulf of Mexico. The European (ECMWF) shows a weak system in the Bay of Campeche on Tuesday, June 20.

All of the models are forecasting the development of a weak low, with the exception of the CMC, which has a robust system rolling up Florida’s West Coast.

However, National Weather Service forecasters in Houston are skeptical:

“Overall conditions are not favorable for tropical cyclone development in the Gulf of Mexico over the next 7 days,” they said in Saturday morning’s weather analysis.  “Synoptic forecast models are behaving as expected beyond 7 days with the development of a model ‘cane’ of some sort with a tropical wave that moves into the Yucatan the following Sunday/Monday June 18/19 time frame.

“There is no consistency or solid signal in the models to believe these details in the models. These types of model ‘canes’ typically remain in the 7-10 day forecast range with each successive model run and never materialize.”

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ORIGINAL POST: It ain’t over till it’s over, as famous baseball forecaster once said, and although things appear to have dried out a bit over South and Central Florida late this week, more rain may be on the way.

Another shot of precipitation looks to be in the cards for Saturday as a pool of moisture in the Caribbean and over the Bahamas gets pushed back over the Florida peninsula, the National Weather Service says. It’s expected to meet up with an old frontal boundary and juice it, bringing showers and a few storms.

“It does not currently look like another widespread heavy rain threat, but locally heavy activity will be possible,” forecasters said in their Friday morning analysis from Miami.

Longer term into next week, the peninsula is finally in an established summer rainfall pattern, with convection most likely in the interior and West Coast areas as Atlantic sea breezes kick up.

RECORD WATCH: Key West logged a rainfall record on Wednesday that had been standing for 141 years. The 4.39 inches of rain obliterated the old mark of 1.62 inches set on June 7, 1876, two weeks before the Battle of the Little Bighorn in Montana.

The low in Naples Thursday was 80, breaking the record warm minimum temperature of 79 set in 1957.

The high in Gainesville Thursday was 73, busting the record for coolest high temperature — 79, set in 2012.

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TROPICS WATCH: The GFS continues to toss around the idea of a tropical system in the Gulf of Mexico the week of June 18. It has alternately shown the system going into Florida, the northern Gulf Coast, and the South Texas coast.

The Canadian model (CMC) supports the idea and Friday’s run has the system rolling up the West Coast of Florida. The European (ECMWF) suggests something may be afoot around that time near the Yucatan Peninsula, and the Navy forecast model (NAVGEM) suggests that something may spin up in the Caribbean, south of Cuba, by next Friday.

Nothing is on the Atlantic forecast map at the National Hurricane Center, but forecasters say a low pressure system may form in the Pacific south of Mexico — around the same place Tropical Beatriz formed — by around mid-week. It has been given a 20 percent chance of development into a tropical depression, or Tropical Storm Calvin, over the next five days.