Hurricane Irma

IMPORTANT:  I use this blog entry to document Hurricane Irma.  It is a place to store images, graphics and some forecast thoughts regarding this storm of national interest.  It is also viewed mostly by friends and family.  While forecast reasoning closely follows that of the experts at the National Hurricane Center, information here should NOT be used to make life or death decisions.  If you have stumbled upon this looking for information that is critical to you, I would advise you to only get your information straight from the National Hurricane Center – local National Weather Service office – and local media relaying information from your city, county and state officials.

Sunday, September 10, 2017 – 1 pm:

…Irma remains Category 4 hurricane with maximum sustained winds of 130 mph and a central pressure of 933 mb…

…Moving north directly toward Marco and Naples, Florida…

Sunday, September 10, 2017 – 6 am:

…Northern eyewall of powerful Irma beginning to overspread the Florida Keys…

…Center of storm is 18 miles south of Cudjoe Key, or 24 miles east southeast of Key West…

…Key West radar measuring what appears to be reliable 146-153 knot winds about 1000 ft off the ground in northern eyewall…

…Maximum sustained winds 130 mph and minimum central pressure is 929 mb…

…Irma is a very dangerous Category 4 storm…

…Measured wind gusts to 94 mph in Key West…

…Most serious short-term impacts to be felt in Big Coppitt Key, Cudjoe Key, Summerland Key, Big Pine Key.  Catastrophic damage due to wind and storm surge is likely in these areas…

…Storm has moved to the north northwest at 10 mph over the last couple of hours…

After passing north of the Florida Keys, Irma will move north northwest before making landfall near or just south of Tampa as a major hurricane.  Life-threatening wind and storm surge is expected across the west-central and southwest coast of Florida.  Some weakening is expected / due to increasing vertical shear / as the storm tracks along the northwest coast of Florida on Monday.

Sunday, September 10, 2017 – 1:20 am:

The hope that Irma could remain below Category 4 strength was short-lived.  Irma has strengthened to Cat 4 with sustained winds of 130 mph.

Movement has now become steady to the northwest at about 7 mph.  The storm is currently located 55 nautical miles south southeast of Key West, Florida.

Sunday, September 10, 2017 – 12 am:

…Hurricane Irma is located about 73 miles south southeast of Key West, Florida and moving to the northwest at about 7 mph…

…Latest wind gusts include 69 mph at Dry Tortugas, 62 mph at Fowey Rocks, and 56 mph at Key West…

…Winds earlier gusted to 68 mph at Key West…

…Irma remains a major, Category 3 hurricane with maximum sustained winds of 120 mph and a minimum central pressure of 931 mb…

As of Midnight, there is little indication that the hurricane is strengthening.  Given a track across very warm ocean water, it is possible that Irma could strengthen back to Category 4 strength.   However, shear across the storm is increasing and this will be a mitigating factor.  The current forecast keeps Irma just below Category 4 strength through final landfall, but the storm will still be a very dangerous hurricane with extreme wind damage and storm surge near and either side of the core.

Wind damage, flooding rainfall and tornadoes will be a threat across all of Florida through Monday morning.

Saturday, September 9, 2017 – 5 pm:

…Irma located about 95 nautical miles southeast of Key West…

…Movement is west northwest about 10 mph…

…A turn to the north northwest is expected this evening and overnight…

Hurricane Irma’s interaction with Cuba overnight and this morning resulted in the storm weakening some.  Maximum sustained winds are 125 mph (Category 3), the central minimum pressure is 933 mb, and the eye has been cloud-filled.  People should not focus on this weakening trend as the pressure has fallen 8 mb over the past few hours, the center is beginning to move across deeper water away from Cuba, and the presentation on satellite and radar is improving.  All indications are that Irma will likely regain Category 4 strength tonight, and be a catastrophic hurricane when it reaches the Florida keys tomorrow morning.

There has been little in the way of change to the forecast reasoning.  The powerful storm will move northward along the west coast of Florida through Monday morning.  Hurricane Warnings extend westward across the central Florida Panhandle, and on the east coast, northward to the Georgia border.

Tropical storm conditions have overspread the Keys and far south Florida.  Recent wind gusts include 66 mph at Marathon, 49 mph at Fowey Rocks, and 47 mph at Key West.

Tornado Warnings have recently included portions of Broward, Collier, and Monroe counties.

On a side note, a comparison was made to events which occurred in September of 2010.  In an eerie way, there were three storms in nearly similar positions as what has recently occurred.  The three were of similar size – and all were named with the same first letter from west to east.

Saturday, September 9, 2017 – Noon:

…Tornado Watch issued for south Florida and Florida keys…

…Several Tornado Warnings have already been issued…

…Conditions across far south Florida and the Keys beginning to deteriorate…

…Winds gusting to 68 mph being reported at Fowey Rocks lighthouse, 60 mph at Marathon, Florida…

During its brush with northern Cuba, Irma weakened some and has sustained winds of 125 mph and a central pressure of 941 mb.  Irma is located about 135 nautical miles southeast of Key West, Florida moving to the northwest at 15 mph.  Irma is now moving away from Cuba and intensification is expected to begin soon.

Saturday, September 9, 2017 – 9 am:

… Eye of Irma showing up on radar about 160 nautical miles southeast of Key West, Florida…

…Irma’s brush with Cuba has weakened the storm some overnight…

…Still Category 4 storm with maximum sustained winds of 130 mph and a minimum central pressure of 937 mb…

…Outer bands have been overspreading the Keys and south Florida…

…Tornado threat increasing across south Florida…

…Winds are gusting to 43 mph in Marathon and 41 mph in Homestead, Florida…

…Preparations to protect life and property should be completed in south Florida and rushed to completion in central and northern sections of the state…

The forecast track has remained relatively unchanged overnight.  Irma is expected to cross the Florida Keys by late tonight and early Sunday, and move up the west coast of Florida during the day tomorrow.  Irma could strengthen some while crossing the warm waters of the Florida Straits – even if it doesn’t – the storm will still be a major hurricane at landfall with the potential to produce life-threatening wind and storm surge.

Even with Irma weakening after landfall, damaging winds, flooding rainfall, and a risk of tornadoes will spread north across the entire state of Florida on Sunday and Monday.

Those living in the Florida Panhandle and southern Georgia should keep up to date on information concerning Irma.

 

Friday, September 8, 2017 – 11 pm:

…Irma regains Category 5 strength…

…Forecast track shifts slightly westward again…

Maximum sustained winds have increased to 160 mph and the minimum central pressure is 924 mb.  Irma is located about 300 miles south southeast of Miami, Florida, moving to the west at 13 mph.  Forecast guidance continues to turn the storm to the northwest and then north northwest by Saturday evening, reaching the Florida Keys by Sunday morning.  Irma is expected to track northward – very close to the western coast of Florida – during the day Sunday.  Should much of the eye be able to remain over water, the storm will be able to maintain intensity longer, possibly extending the danger of extreme wind and deadly storm surge to the Tampa area.

Irma is a wide storm and even a track along the west coast will not keep hurricane conditions from occurring along the east coast.  Damaging winds, flooding and the risk of tornadoes will likely overspread at least the southern two-thirds of the state.

Friday, September 8, 2017 – 6 pm:

…Irma remains dangerous Category 4 hurricane this evening…

…Maximum sustained winds are 155 mph and the minimum central pressure is 925 mb…

…Forecast track of Irma nudged west by the National Hurricane Center, opening up more of the Florida Keys and southwest Florida coast to extreme danger…

…Preparations to protect property should be rushed to completion…

…Time for evacuation is running out this evening as tropical storm conditions are expected to begin arriving across the Keys and far south Florida by tomorrow morning…

The official track forecast now takes Irma over the central portions of the Florida Keys with an eventual final landfall south of Naples, Florida.  This track would result in catestrophic damage across the Keys and south Florida with life-threatening storm surge flooding across much of south and particularly southwest Florida.  People that have yet to evacuate these areas are urged to do so in these final hours before evacuation will become impossible.

Also… it is important not to focus on the exact forecast track.  There will likely be some error in the forecast and anyone under a Hurricane or Storm Surge Warning should treat the situation as if the track will be directly over them.

As Irma continues northward across Florida on Sunday, expect damaging winds that may approach 100 mph to extend to the central sections of the state.  Those not along the immediate coast will still have the potential of receiving considerable wind damage, flooding and a risk of tornadoes.

Friday, September 8, 2017 – 9 am:

…Hurricane Irma slightly weaker but remains catestrophic Category 4 storm…

…Maximum sustained winds are 150 mph and the minimum central pressure is 927 mb…

People should not focus on the slight weakening that has taken place over the last 24 hours.  The hurricane is still a large and powerful storm capable of producing extreme risk to life and property.  Irma is threading the needle between the Bahamas and Cuba and is expected to remain over unseasonably warm ocean waters, and in an environment favorable for maintenance or intensification.

Irma is expected to be crossing over the Upper Florida Keys and south Florida during the early morning hours of Sunday.  As we are now within 72 hours of landfall, the forecast cone is narrowing, and confidence is increasing with regard to the threat to south Florida.

Warning has been more than adequate, and has had as long of lead time as can be expected given the current forecast science.  Preparations to protect property should be wrapped up soon.  People that live in the Hurricane Warning still have time to act, and should follow the advice of recommended and mandated evacuation orders.  Irma will be a life-threatening storm at landfall.

The current forecast track takes the storm / which will be weakening after landfall / northward through the middle of Florida.  Despite the post-landfall weakening, residents living as far north as the Georgia border can expect the potential for damaging winds, as well as the associated flooding and tornado threats.

The forecast cone at 96 hours continues to cover a region from the Florida Panhandle to South Carolina.  Folks in these areas should stay up to date on the progress of Irma.

Thursday, September 7, 2017 – 11 pm:

…Irma weakens slightly during the day but remains dangerous Category 5 storm…

…Currently pounding Turks and Caicos Islands, will be moving into the southeast Bahamas tonight…

…Hurricane core expected to move between the Bahamas and Cuba over the next couple of days…

…People living from the Florida Panhandle to North Carolina should stay up to date on forecasts regarding Irma…

…Those in Hurricane Warning areas should act now to protect life and property, and follow any recommended or mandated evacuation orders…

Maximum sustained winds have lessened slightly to 165 mph and the minimum central pressure is 920 mb.  This still makes Irma a solid Category 5 storm.  Some fluctuations in strength are possible over the next 24 to 48 hours, but Irma will remain at Category 4 or 5 through that period.

The current forecast calls for Irma to slow slightly and begin to turn toward northwest toward southern Florida by Saturday evening.

Warnings have been raised for portions of Florida:

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

 

A Storm Surge Warning is in effect for…

* Jupiter Inlet southward around the Florida peninsula to Bonita

Beach

* Florida Keys

 

A Storm Surge Watch is in effect for…

* North of Jupiter Inlet to Sebastian Inlet

* North of Bonita Beach to Venice

 

A Hurricane Warning is in effect for…

* Jupiter Inlet southward around the Florida peninsula to Bonita

Beach

* Florida Keys

* Lake Okeechobee

* Florida Bay

* Haiti from the northern border with the Dominican Republic to Le

Mole St. Nicholas

* Southeastern Bahamas and the Turks and Caicos Islands

* Cuban provinces of Camaguey, Ciego de Avila, Sancti Spiritus, and

Villa Clara

* Central Bahamas

* Northwestern Bahamas

 

A Hurricane Watch is in effect for…

* North of Jupiter Inlet to Sebastian Inlet

* North of Bonita Beach to Anna Maria Island

* Cuban provinces of Guantanamo, Holguin, Las Tunas and Matanzas.

 

A Tropical Storm Warning is in effect for…

* Haiti from south of Le Mole St. Nicholas to Port-Au-Prince

* Cuban provinces of Guantanamo, Holguin, and Las Tunas

Thursday, September 7, 2017 – 7 am:

 

…Irma weakens ever so slightly overnight – still powerful, Category 5 storm…

…Maximum sustained winds are 180 mph and the minimum central pressure is 921 mb…

…Storm surge of 15 to 20 feet expected across the central and southeast Bahamas and Turks and Caicos Islands…

…Hurricane watches or warnings likely for parts of Florida later today…

The latest model guidance and the official forecast moves Irma west northwestward to just southeast of the Florida coast in about 72 hours.  A northward turn is expected at that time and the storm is forecast to move north along, or just east of the Florida coast before making a final landfall near or east of the Georgia/South Carolina border.  While slow and steady weakening is forecast, Irma should remain a major hurricane (Category 3 or greater) until landfall.

It appears at this time that the threat of a direct hit by Irma to the Florida Panhandle and west coast of Florida is lessening.  However, people are reminded that forecasts greater than 72 hours often have large errors in both track position and intensity.  Everyone from the Florida Panhandle to North Carolina should continue to remain up to date on the latest information concerning Irma and be prepared to act if watches or warnings are issued.

 

Wednesday, September 6, 2017 – 11 pm:

… Little change in Irma today – remains Category 5 storm with winds of 185 mph and minimum central pressure of 916 mb …

…Irma has set a record for the longest lived Category 5 storm…

…Hurricane watches and warnings will be required for Florida on Thursday…

…Those living in hurricane-prone areas are urged to review plans and ACT when advisories are issued…

Irma is now moving away from Puerto Rico.  The storm is located 85 miles north northwest of San Juan and moving to the west northwest at 16 mph.

The forecast track takes Irma across the southern Bahamas through Friday evening, and approaching southeast Florida by Saturday evening.  The current forecast moves the hurricane north along the east coast of Florida, Sunday and early Monday, before an eventual final landfall near the Georgia/South Carolina border.  Forecasters will remind people that errors in the forecast track and intensity can be large at greater than 72 hours.  Anyone living from the Florida Panhandle to North Carolina should stay up to date on information concerning Hurricane Irma.

Wednesday, September 6, 2017 – 6 am:

…Irma remains extremely dangerous Category 5 hurricane with sustained winds of 185 mph and central minimum pressure of 914 mb…

…Barbuda, Saint-Martin, Anguilla being hit hard by storm…

…Slight changes in official forecast track and strength…

Hurricane Irma pounded Barbuda this morning.  A surface observing station on the island saw winds gust to 155 mph during eyewall passage where the pressure dropped to almost 920 mb.  The anemometer stopped working at some point and was not reporting during the passage of the backside of the eye.

Hurricane Warnings have been extended into the southeast Bahamas.

Irma has likely peaked in strength.  The bad news is that the storm will stay at or above the threshold of a category 5 storm for about 72 more hours.

The forecast track has shifted slightly northeast, keeping it just off the coast of Cuba as it moves by on Saturday.  During the early morning hours of Sunday, Irma should be located about midway between the southern tip of Florida and Cuba and beginning its anticipitated turn toward the north.  While it is still likely to be a major storm (category 3 or higher), winds are forecast to reduce some due to slowly increasing vertical shear.

Watches and warnings could be required for portions of Florida later today.  Residents in hurricane-prone areas are advised to review plans and act when advisories are issued.  Historically, large errors occur in forecast tracks and intensities at time periods longer than 72 hours.  With this in mind, anyone living from the Florida Panhandle to North Carolina should stay up to date on the progress of Irma.

 

Tuesday, September 5, 2017 – 5 pm:

… Irma extremely dangerous Category 5 with sustained winds of 185 mph and central minimum pressure of 926 mb …

… Only Hurricane Allen (190 mph) in 1980 was a stronger storm in the Atlantic basin …

… Catestrophic damage expected across the far northern Leeward Islands through Wednesday afternoon …

Model guidance is tightly clustered through 120 hours and suggests that a major hurricane will be located just south of the southern tip of Florida by that time (Sunday afternoon).  Most guidance / and the official forecast / brings the center of Irma very close to or over portions of northern Cuba late Friday and early Saturday.  Should this occur, this will have a significant impact on the structure and intensity of the storm.  Leaning toward this solution, the hope is that Irma will be down to at least category 3 by the time a Florida landfall occurs.  Category 3 storms are still capable of producing significant damage and threat to life.  Anything greater would increase those risks.

It is important to remember that at this range (96-120 hours) – large errors in forecast positions and strength are common.  Anyone living from the Florida Panhandle to North Carolina should keep up to date on information concerning Irma.

Expect watches and warnings for portions of the Florida Peninsula during the next 24 to 48 hours.  All people living in the Florida Keys and southeast Florida should have a plan in place and be prepared to act once various advisories are initiated.

Tuesday, September 5, 2017 – 7 am:

… Morning finds Irma much stronger …

… Now extremely dangerous and rare Category 5 with sustained winds of 175 mph …

… One of the strongest storms recorded in the Atlantic basin …

The minimum central pressure has fallen overnight to 929 mb.  There has been very little change in the forecast track by model guidance, and the official forecast has followed suit.

The dangerous core of Irma will move over portions of the northern Leeward Islands tonight and early Wednesday.

Confidence continues to increase that this major hurricane will be near the southern tip of Florida this weekend.  All people in hurricane-prone areas of the Florida Keys and south Florida are urged to review their plans of action, and be prepared to act if watches or warnings are issued over the next 48 hours.

Monday, September 4, 2017 – 4 pm:

… Hurricane Irma now dangerous Category 4 storm …

Hurricane Irma has intensified throughout the day and now has sustained winds of 130 mph.  The minimum central pressure is 944 mb.  Currently located about 490 miles east of the Leeward Islands, the storm is moving west at 13 mph.

First in line for the potential of significant damage from this storm include: Antigua, Barbuda, Anguilla, Montserrat, St. Kitts, Nevis, Saba, St. Eustatius, Sint Maarten, Saint Martin and Saint Barthelemy.

A Hurricane Watch is in effect for: Guadeloupe, British Virgin Islands, U.S. Virgin Islands, Puerto Rico, Vieques, and Culebra.

Model guidance has been clustered nicely over the last 24-48 hours.  There is an increasing chance of seeing impacts from Irma in the Florida Peninsula later this week and this weekend.  Everyone in hurricane-prone areas should have their hurricane plans in place and stay up to date on information concerning this storm.