Irma forecast shift puts Florida Keys — and peninsula — in play

TS winds

LATE MONDAY UPDATE: At least 5 percent probabilities of tropical storm force winds spread through the entire Florida peninsula Monday night, reaching 30-50 percent in South Florida over the next five days. (Credit: NHC)

ORIGINAL POST: A stunning shift to the southwest for the Hurricane Irma forecast have put the Florida Keys in play for impacts late this week.

Needless to say, this has been an evolving forecast and major changes can and have been taking place every six hours, with new information coming out of the National Hurricane Center. Forecast model runs have moved west and south over the past several days.

Early Monday morning, the Keys were in a 10 percent probability bracket for tropical storm force winds by late Friday or early Saturday morning, and that 10 percent edged up into southeastern Florida as well. The 20 percent probability bracket was just off-shore and a 40 percent bracket was moving into Andros Island in the Bahamas.

Monday’s major forecast models showed Irma skirting the coast of Cuba and then making a sharp right turn into the Keys and the Florida peninsula. NOAA’s GFS had the storm moving over Havana and then into the Keys before riding up the state as a blockbuster hurricane.

The European (ECMWF) had Irma making the sharp right turn sooner, moving off the coast of Cuba and plowing north just off Florida’s East Coast. The Canadian model (CMC) favored the GFS track, although it kept the storm off the coast of Cuba. The Navy model (NAVGEM) also pulled it into the Florida peninsula from the south.

Expect more adjustments from the models — meteorologists said the , but as the weekend approaches, forecasts will begin consolidating.

The NHC’s Robbie Berg said in the agency’s early morning analysis: “Remarkably, the track models are very tightly clustered through day 5, which increases the confidence in the westward shift of the latest NHC forecast.”

Track errors at five days out are about 225 miles on average, Berg noted, and he reminded readers that strong winds and heavy rain extend “well away” from the center.

A NOAA Hurricane Hunter aircraft investigating Irma reported at 8 a.m. that winds had increased to 120 mph with higher gusts, and the hurricane-force winds extended 30 miles from the center. Tropical storm-force winds extended 140 miles from the center.

“Additional strengthening is forecast through Tuesday night,” the NHC said.

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Late Monday forecast tracks for Hurricane Irma. (Credit: SFWMD)

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Melbourne slammed with over 4 inches of rain; tropical storm wind probabilities edge into South Florida

Coastal Brevard County was swamped Saturday with more than 3 inches of rain, and Melbourne reported an official total of 4.62 inches — almost double the single-day rainfall record set in 1977.

The one-day deluge was less than an inch shy of Melbourne’s total for the entire month of August — 5.31 inches.

Drier weather was forecast in Central and South Florida to start the week, but rain chances pick up by mid-week as a front moves into North Florida.

wind speed probabilities

LATE SUNDAY UPDATE: Probabilities of tropical storm force winds — already at 5 percent and close to 10 percent by Friday — edged into South Florida for the first time Sunday night, as Hurricane Irma continued to plow west-southwest in the Atlantic east of the Lesser Antilles. Winds were at 115 mph. The “time window of greatest concern” is Friday through Monday, forecasters in Miami said. Hurricane watches were issued Sunday night for parts of the Leeward Islands including Antigua, Barbuda, Anguilla, Montserrat, and St. Kitts. “Additional Hurricane and Tropical Storm Watches may be required for portions of this area on Monday,” the National Hurricane Center said.. (Image credits above and below: NHC)

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ORIGINAL IRMA POST: The five-day forecast track was adjusted about 138 miles to the west early Sunday morning by the National Hurricane Center  — not a welcome trend for people in the Bahamas and the coastal areas of the U.S. who are hoping power-packed Irma stays out to sea.

The 120-hour forecast issued at 11 p.m. Saturday put Irma at 22.5N and 69.5W, while the 5 a.m. advisory put it at 22.5N 71.5W. (The 11 a.m. Sunday five-day put it at 22.0N 72.0W.)

If you live in the Bahamas, Florida’s East Coast or North Carolina, the best thing you could say about Sunday’s forecast model runs on Hurricane Irma was that they are likely to change over the next seven days.

NOAA’s GFS had a say-it-ain’t-so 893 mb hurricane spinning next Sunday about 275 miles east of Palm Beach. For comparison purposes, Hurricane Wilma’s record-shattering lowest central pressure in 2005 was 882 mb, which generated sustained winds of 185 mph in the Caribbean.

Landfall in that particular GFS Sunday run was in North Carolina late Monday, September 11.

The European model (ECMWF) pushed Irma to around 175 miles southeast of Miami on Sunday and — like the GFS — kept it just off Florida’s coast but smacked it into North Carolina on Tuesday.

The morning run of the Canadian (CMC) drove it into Florida’s East Coast on Sunday, then ripped it up the peninsula before exiting back into the Atlantic around Daytona Beach.

The NHC emphasized again on Sunday — as it has with each advisory — that it’s “much too early to determine what direct impacts Irma will have on the Bahamas and the continental United States. Regardless, everyone in hurricane-prone areas should ensure that they have their hurricane plan in place, as we are now near the peak of the season.”

The South Florida forecast for next weekend calls for windy conditions. “As the ensembles and operational models gain a better consensus, will be better able to look at what impacts, if any, Irma will have on South Florida,” Miami-based NWS forecasters said in their Sunday analysis. “It may be several days yet before a better consensus takes shape.”

NWS forecasters in Melbourne said: “Just how close Irma will eventually get to the Bahamas and the Florida east coast will not be known for several days. However, given the strength of the system and the overall agreement that the system will be approaching the Bahamas, it is prudent for people in east central Florida to closely monitor the system, including forecasts from the National Hurricane Center, and National Weather Service, throughout the week.

“Now is also the time to review your personal hurricane plan, and ensure you have a fully stocked hurricane supply kit.”

 

Wettest summer ever in Naples; Florida anxiously eyes Irma

Naples had its wettest summer on record, the National Weather Service said Friday. A June-August total of 41.42 inches was measured, easily beating the previous summer record total of 36.61 inches recorded 70 years ago in 1947.

Labor Day Hurricane anniversary

ANNIVERSARY: The 1935 Labor Day plowed into the Florida Keys 82 years ago with sustained winds of 185 mph. The center made landfall near Long Key. It was the most powerful hurricane to hit the U.S. since record keeping began in 1851. (Credit: NWS-Key West

IRMA WATCH: NOAA’s GFS and the European forecast model (ECMWF) have been coming into closer agreement on a longer-term path for Hurricane Irma. But one thing they agree on already: This is going to be a doozy.

Saturday’s run of the European showed a 921-mb hurricane passing over or near Grand Bahama on Sunday, September 10; The GFS had a 925-mb storm about 400 miles to the east of Grand Bahama next Friday. For comparison purposes, Hurricane Harvey had a minimum central pressure of 938 mb when it slammed into Texas as a Category 4 with 130 mph winds.

The Canadian (CMC) basically split the difference between the two, with a 971-mb storm over or near Great Abaco (to the east of Grand Bahama). The Navy model (NAVGEM) had Irma about 700 miles east of Palm Beach in the Friday-Saturday time frame with a central pressure of 944 mb.

As far as the ensembles for the major models, three of the 20 GFS Ensembles showed a Florida East Coast hit (15 percent); nine of 50 ECMWF Ensembles showed a Florida hit or coastal scrape (18 percent); and seven of 20 CMC Ensembles showed a Florida hit or coastal scrape (35 percent).

TS wind probabilities

LATE SATURDAY UPDATE: Probabilities of tropical storm force winds began creeping into the Central Bahamas. (Credit: NHC)

Many other ensemble members suggest an Irma landfall somewhere along the U.S. East Coast — some as far north as New York and New England.

Forecast models are refreshed every six to 12 hours, so this is just a snapshot of one Saturday analysis.

The difference in the models – particularly the ECMWF and the GFS — is based on differing analyses of the trough forecast to plow into the Southeast by mid-week, according to the National Weather Service.

Forecasters at the NWS in Melbourne explained in their Saturday discussion:

“The forecast for late week, and especially into next weekend hinges largely upon the speed at which the … trough lifts out to the N-NE. The 00Z operational runs of the ECM/CMC show this taking place faster than the GFS. This allows the post frontal surface high to link up with the Atlantic ridge more quickly, which in turn brings major Hurricane Irma uncomfortably close to Florida by next Saturday.”

“It remains much too early to have any sort of handle on whether the system will directly impact Florida, or, for that matter, any spot along the east coast of the U.S., and will remain the case well into next week.”

REGARDLESS OF IRMA: A wetter week is in store for the Florida peninsula as showers and storms move in from the Gulf of Mexico over the weekend, and the front approaches North Florida by mid-week.

RECORD WATCH: Daytona Beach hit 95 degrees Friday, breaking the previous record high of 94 set in 2000. Vero Beach tied a record high with 94.

Melbourne logs warmest August on record; forecasters weigh Hurricane Irma threat

Melbourne had its hottest August on record, the National Weather Service reported Friday. The average temperature for the month was 84.6 degrees, busting the previous record of 84.2 degrees set in 2007.

The average high was 92 and the average low was 77.

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The National Hurricane Center was watching a new disturbance southeast of Hurricane Irma. (Credit: NHC)

The future of Hurricane Irma was still cloudy on Friday and was highly dependent on the strength and timing of a cold front set to swoop into the southeastern U.S. next week.

That was the Friday morning analysis from the National Weather Service in Miami.

The trough associated with the front “is likely what will determine Irma`s path for the end of next week,” forecasters said. “Model guidance is still fairly widespread, so there is a huge amount of uncertainty in the forecast at this time. However, the GFS and the Canadian show Irma interacting with the trough, being drawn northward, keeping Irma well to the east of South Florida, having little to no impact on our weather.”

They added: “While models are indicating a favorable track for South Florida, there still is a great amount of uncertainty, especially this far out, and Irma could potentially still pose a threat to South Florida sometime after the forecast period.”

Friday’s initial run of the European model (ECMWF) fell more into line with the GFS in keeping Irma well east of Florida — and even the Bahamas.

Irma was still a major hurricane Friday with winds of 115 mph, and the National Hurricane Center’s official forecast track had it nearing the northeastern Leeward Islands by around the middle of next week as a Category 4 hurricane with winds of 140 mph.

A new tropical wave south of the Cabo Verde Islands was given a 50 percent chance of becoming the next tropical depression, or Tropical Storm Jose, over the next five days. A track to the west was forecast by the NHC, south of Irma.

AUGUST ROUNDUP: The month — and the meteorological summer — ended Thursday with temperatures running up to 1.7 degrees above average. Miami and West Palm Beach logged August precipitation deficits, but Fort Lauderdale had 14.54 inches of rain for the month — 7.1 inches over normal.

Naples’ 15.55 inches was 6.97 above average.

The Keys were dry, though, with Key West reporting a 3.15-inch rainfall deficit and Marathon a hefty 4.56-inch deficit. Temperatures were about a degree-and-a-half above average for August in the Keys.

Fort Pierce also turned in a big August rainfall deficit of 3.57 inches while Vero Beach and Daytona Beach were about a half-inch short. Melbourne’s rainfall deficit was 2.37 inches; Orlando came up 1.14 inches short.

Jacksonville ended the month was a rainfall surplus of 2.29 inches.

Meanwhile, Florida’s West Coast also had an unusually wet August — Tampa was almost 3 inches above normal.

And Sarasota-Bradenton reported a surplus of almost a foot of rain, with an amazing total of  20.97 inches for the month. Fort Myers precipitation was about 7 inches above average.

RECORD WATCH: Record warm minimum temperatures were reported on Florida’s East Coast on Thursday. Miami’s low of 84 tied the all-time record warm low for the second time in the month. It beat the previous low for the date of 83 set in 2001.

Fort Lauderdale’s low of 83 tied the record warm for the date set in 2001; and West Palm Beach’s low of 83 tied the mark set in 2008. Key West’s low of 85 beat the previous record warm low of 84 set in 2001.

Irma becomes major hurricane as it approaches Antilles

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(Image credit: NHC)

UPDATE 2: Irma became the second major hurricane of the 2017 season at 5 p.m. with winds of 115 mph, and it was forecast to become a Category 4 on Monday with winds of 140 mph. On the crucial issue of whether Irma will make the advertised longer-range turn toward the north — as depicted by the GFS and other forecast models — the NHC’s Eric Blake said: “I am inclined to stay on the southwestern side of the model guidance, given the rather consistent forecasts of the ECMWF and its ensemble. In addition, the strongest members of the recent ensembles are on the southern side on the consensus, giving some confidence in that approach.” The ECMWF, or European model, predicts that Irma will be over or near Key West on Sunday, September 10 as a very powerful hurricane.

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UPDATE 1: Irma jumped from tropical storm status at 5 a.m. to a Category 2 hurricane with 100 mph winds six hours later. From the 11 a.m. EDT NHC discussion by forecaster Eric Blake:

  • “Satellite imagines indicate that Irma is rapidly intensifying.”
  • “Irma has moved somewhat south of and slower than all of the model guidance since yesterday. Consequently, it stayed longer over the warmer ocean temperatures away from the drier air to the north, possibly allowing the rapid strengthening.”
  • “The NHC forecast shows an extremely dangerous category 4 hurricane next week, similar to the solutions provided by the HWRF and the ECMWF models.”
  • “Guidance continues to trend southward, following the trend of the ECMWF model starting yesterday. Given the strength of the ridge and depth of the tropical cyclone, there are no obvious reasons to discount the anomalous west-southwestward motion seen in most of the guidance. Little change is made to the track forecast in short-range, but the track is shifted southward and westward at long-range, though not as far southwest as the overnight ECMWF and ECMWF
    ensemble models.”

ORIGINAL POST: Irma neared hurricane strength Thursday and forecasters predicted it would power up into a major hurricane with winds approaching 120 mph over the weekend.

It was nail-biting time for the Lesser Antilles and points west.

All of the major forecast models on Thursday — with the notable exception of the European (ECMWF) — had Irma making a northwest turn as it approaches the Leeward Islands and heading north, well east of the Bahamas. However, the GFS showed it hitting North Carolina as a powerful hurricane on Sunday, September 10.

As for the European, it remained the outlier, moving Irma through the Greater Antilles and arriving in Cuba near Havana on September 10.

Both major models also show another, weaker Gulf of Mexico system coming ashore in the far western Florida panhandle that weekend.

This doesn’t mean that the Florida peninsula or the Keys are out of the woods with Irma. Track forecasts are not reliable 10 days out.

The European model, and its 50 ensemble members, were clearly seeing something the other models were not. Whether they fall into line with the other models, or the other models trend toward the European solution, will be the big question over the next several days.

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RAIN FORECAST SATURDAY: Wednesday’s heat index reached 105 in Miami and West Palm Beach, 103 in Naples and 102 in Fort Lauderdale. More of the same was forecast through Friday, but rain chances rise Saturday, according to the National Weather Service, as the remnants of Tropical Depression Harvey push precipitation into North and Central Florida.

A strong cold front dives into the U.S. Southeast by the middle of next week, driving overnight lows into the 50s as far south as Georgia. The front should make into at least North Florida, which would push up rainfall chances again in South and Central Florida.

Tropical Storm Irma spins up in Atlantic, forecast to become hurricane

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Tropical Storm Irma spun up in the far eastern Atlantic Wednesday, and the National Hurricane Center predicted it would become a hurricane by Friday. Potential impacts on the U.S. — if any — remain uncertain. (Credit: NHC)

The Atlantic hurricane season’s ninth named storm formed in the deep Atlantic on Wednesday as history-making Tropical Storm Harvey made its final landfall in southwestern Louisiana.

The National Hurricane Center initiated advisories on Tropical Storm Irma at 11 a.m. and predicted it would continue on its track to the west, followed by an unusual turn toward the southwest, over the next five days at a speed of about 13 mph.

It’s too early to assess potential threats to the U.S. East Coast. Forecast models have been flip-flopping on Irma, with the GFS showing a Florida Keys hit in its runs on Tuesday, then a back-out-to-sea scenario early Wednesday.

The European (ECMWF) has been more consistent, suggesting a track just to the north of the Greater Antilles and a possible approach to the Bahamas late next week.

It’s a typical wait-and-see setup for the new storm, and the fate of Irma should start to come into focus over the weekend.

Harvey made landfall in the early morning hours just west of Cameron, Louisiana and was heading inland — for good this time, according to forecasters. It will gradually lose its punch as it moves northeast, but the NHC’s Robbie Berg noted: “This weakening will not eliminate the risk of continued heavy rainfall and flooding along Harvey’s path, although the system’s faster motion will prevent rainfall totals from being anywhere near what occurred over southeastern Texas.”

Harvey rainfall perspective

Harvey’s rainfall totals were close to what many Central Florida cities expect for the entire year, the National Weather Service noted. (Credit: NWS-Melbourne)

Not surprisingly, Harvey broke the U.S. tropical cyclone rainfall record with Cedar Bayou, near Mont Belvieu, Texas, reporting 51.88 inches from the storm. That rainfall total beat Tropical Storm Amelia’s 1978 total in Medina, Texas.

“The all-time United States tropical cyclone rainfall record of at least 52 inches occurred during tropical cyclone Hiki in Kauai, Hawaii in 1950,” the National Weather Service said in a statement. “It is certainly still possible rainfall from Tropical Storm Harvey may exceed the all-time United States record, but no official rain gauge has reported a value in excess of 52 inches as of 5 pm EDT [Tuesday].”

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BAKING IN VERO BEACH: Florida East Coast temperatures rebounded Tuesday as high pressure built back into the peninsula. Miami posted a high of 94 with heat index values as high as 106. Fort Lauderdale reported 92/ 105 and West Palm Beach, 91/ 103. Naples’ high was 90 with a maximum heat index of 102.

It was 96 in Vero Beach and Melbourne, and 94 in Fort Pierce.

The forecast for the end of the week is for the heat index to approach 108 degrees, with temperatures stuck around 90 into Saturday, Sunday and Monday — the first weekend of the meteorological fall.

In Florida, the start of autumn looks an awful lot like summer.

The Manatee County government released this video of flooding in the area on Monday following a week of heavy rains from tropical disturbance 92L. (Credit: Manatee County via NWS-Tampa)

 

North Florida summer 2017: ‘Dry days have been far and few between’

The summer of 2017 is setting records in North Florida for the wettest season ever.

Jacksonville is headed for its wettest May-August period since at least 1872, with more than 40 inches of rain already on the books. Gainesville surpassed its summer rainfall record (June-August) earlier this month.

Jax rainfall record
It’s been a wet-and-wild summer in Jacksonville. (Credit: NWS-Jacksonville)

“It started raining during the second half of May, and dry days have been few and far between for a good portion of northeast and north central Florida ever since,” meteorologists at the National Weather Service in Jacksonville said Monday.

In West-Central Florida, several counties were still under a Flood Watch on Tuesday for more rain with a few spots under a Flood Warning. Some areas along the Manatee River were under a Flood Warning through Wednesday afternoon. The river hasn’t crested this high since 1975, according to the National Weather Service in Tampa.

South Florida was relatively dry on Monday. Fort Lauderdale was an exception, with 2.33 inches of rain beating the previous single-day record for August 28 of 2.20 inches set 91 years ago in 1926.

Florida has lucked out so far with hurricanes, but we are now headed into the meat and potatoes of the season.

Eastern Atlantic wave

A tropical wave near the Cabo Verde Islands was already showing signs of development Tuesday. (Image credit: NOAA)

Invest 93L in the eastern Atlantic was nearing tropical depression status on Tuesday morning, and the National Hurricane Center put development chances at 90 percent.

The GFS continued to show this storm, very possibly a hurricane, getting ushered out to sea. But the European model (ECMWF) was sticking with a more southerly route just north of the Greater Antilles, and reaching the southeastern Bahamas on Friday, September 8 as a humdinger of a hurricane. The Canadian (CMC) is more in line with the GFS.

The ECMWF is one of the most reliable — and relied on — forecast models and it’s too early in the game to write this one off.  Its arrival in the western Atlantic would coincide with the statistical peak of the hurricane season, which is September 10.

Tropical Storm Harvey emerged back into the Gulf of Mexico on Monday and strengthened into a 45-mph tropical storm heading east-northeast toward the coast of southwestern Louisiana. It was devoid of convection around the center due to high wind shear, but rain continued along the Texas and Louisiana coasts.

The NHC predicted Harvey would make a second landfall on Wednesday afternoon and then continue through the center of Louisiana before being downgraded to a tropical depression by late Thursday or early Friday morning in Mississippi.

Potential Tropical Cyclone Ten was moving off North Carolina’s shore and still had a narrow window of opportunity to become Tropical Storm Irma on Tuesday before heading into the Atlantic as a powerful post-tropical storm or hurricane.

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MIAMI HEAT: No, not the basketball team. South Florida highs were expected to return to the low to mid-90s on Tuesday and Miami’s forecast high of 94 is 2 degrees off the record high of 96.

Heat index values were forecast to be as high as 105 around parts of South Florida.