Monster Hurricane #Irma – sat measurements show it larger than the state of Florida is long

From  this imagery earlier, it certainly looks like it. It is certainly wider than the Florida Peninsula, and it’s diameter looks to be as large as Florida is long.

From the National Hurricane Center at 11PM EDT tonight:

Hurricane-force winds extend outward up to 75 miles (120 km) from the center, and tropical-storm-force winds extend outward up to 185 miles (295 km).


Florida is 500 miles long and 160 miles wide at its most distant points.

That includes the Keys and the panhandle. Using Google Earth, I measured the length of the Florida peninsula (minus the Keys) and came up with ~391 miles.

Measuring the size of Irma, based on the densest cloud bands, it shows ~528 miles in diameter from outer dense cloud bands through the eye. I also did a measurement across the panhandle from Tampa to Cape Canaveral and came up with ~139 miles.

With hurricane tropical storm force winds extending “outward up to 185 miles” according to NHC, that means that if the storms holds in strength, the entire width of the Florida panhandle may get tropical storm force winds (39–73 mph, 63–118 km/h). That’s sobering, especially in light of this track projection:

Irma is certainly bigger than hurricane Andrew, seen here in 1992:


81 thoughts on “Monster Hurricane #Irma – sat measurements show it larger than the state of Florida is long

    • Published September 07, 2017

      As Hurricane Irma drew closer to South Florida on Thursday, tens of thousands of drivers headed northward to flee the storm, causing a traffic nightmare that continued into the evening.

      “There was no gas and it’s gridlock. People are stranded on the sides of the highway,” Mari Michaud, a Florida resident who left her home near Cocoa Beach about 10 a.m. with her husband and two children, told the Associated Press. “It’s 92 degrees out and little kids are out on the grass on the side of the road.
      No one can help them.”

      As of 3 p.m. Wednesday, traffic doubled and even tripled on major roadways and interstates, ……
      Read more @

      • Not to discount the size of Irma, but…Bigger than Florida,??? big whoop!!!
        Irma is bigger than Florida.
        Jose is bigger than Florida.
        Katia is bigger than Florida.
        Harvey was bigger than Florida
        Even Cat1 hurricane Franklin was bigger than Florida

    • Sorry, I don’t see an option to view tropical cyclone steering currents (850mb thru 250mb average winds) in nullschool. It is pretty…and basic, but not much else IMO.

      • That trough and the cold front out ahead of it will smack the TC upside the head and it will not make landfall in FL.

  1. My son lives 25 miles SW of Jacksonville I’m hoping he has the smarts to head north, he is dragging his feet right now choosing to wait…stupid hurricanes :0/

  2. Cedar Key to the AL. line is the panhandle. You are measuring the center of the state. We live on the East coast under post Andrew building codes. Didn’t see much point in leaving. Irma track seemed to cover everywhere.

  3. Like most, I have a few friends in Florida, all of whom I’ve counseled to get the hell out of there, right now, do not pass GO, do not collect 200 dollars.

    Not much else to say.

  4. It accelerates the jet stream to the north because of the strong geomagnetic storm. Irma will hit central Florida.

    • Not for nothing, but what could Cuba do for us? They will have their hands full with their own country which will be completely impacted. The US, by comparison, will have less than 10% of it’s population impacted by this storm; less than 20% for both.

      The only question is can we help them in light of our efforts to help our own people, including already devastated Puerto Rico.

      • The have first class medical teams designed to intervene in disasters such as this. They are close by. It could be a act that facilitates better relations between the two neighbours.

    • The US has been sharing hurricane data with Cuba for decades. I believe Cuba allows us to fly hurricane hunter planes from their territory as well.

    • So it’s already weaker than Andrew when it hit South Florida and will continue to weaken as it pulls drier air from over Cuba. That’s some good news.

  5. it’s a normal size

    Andrew was smaller because it intensified suddenly before slamming into the coast with no eyewall replacement cycle.

    Irma is having an eyewall replacement cycle and generally the hurricanes grow in size when they undergo this event.

    problem now is what will it do: stay larger and less intense or will it “shrink and reintensify”?

  6. Heat piracy is the substantial movement of ocean heat between hemispheres, and is linked to the bipolar seesaw, the phenomenon of reciprocity between the hemispheres, where one hemisphere cools as the other warms in a zero-sum-game like manner. The bipolar seesaw results in out of phase oscillation of temperature between the hemispheres.

    The Caribbean current carries ocean heat across the equator from south to north hemispheres, delivering this heat to the Caribbean – an appropriate place for this major incidence of heat piracy.

    A look at today’s ocean surface temperatures by UNISYS shows a striking disparity between a cooler SH and warmer NH. It would seem that the “Pirate of the Caribbean”, the Caribbean current, has been exceptionally busy spiriting heat from the south to the North hemisphere.

    So the present series of strong hurricanes may be indicative of robust heat piracy, warming the Caribbean’s surface waters and thus energising the hurricanes.

    It’s worth mentioning that according to Tzedakis, bipolar seesawing can be expected to increase as the termination of an interglacial and glacial inception approaches. Just saying…

  7. I keep reading that hurricanes are Heat Engines driven by the temperature difference between the ocean surface and the upper level air. Ocean temperatures are reported but I cant find any reports of upper air temperatures or temperature difference of Irma and other strong hurricanes. I suspect that upper air temperatures vary much more that ocean surface temperatures, but where do I find that data ?

    • Curious

      I keep reading that hurricanes are Heat Engines driven by the temperature difference between the ocean surface and the upper level air.

      Also the case as I understand it.

      …I cant find any reports of upper air temperatures … I suspect that upper air temperatures vary much more that ocean surface temperatures, but where do I find that data?

      Producers of lower troposphere (‘upper air’) temperature data derived from satellites suggest that you are right. Upper air temperatures were very high in August. Sea surface temperatures have levelled off after having been unusually high for a long time.

      Check out:-


      And RSS:

      Note that these anomalies are based on different base periods. The absolute differences aren’t so pronounced as they may seem. The point to note is that both satellite data sets reported an increase in global upper air temperature on average during August.

  8. Pedantic copy editor here: It drives me a little nuts that the media do nothing to dispel the public misconception that the satellite image IS the hurricane. “It’s the size of Florida” is BS. It is not, if by “hurricane” is meant a storm with 70+ winds. That storm only exists in the wind field around the eye. Irma the Hurricane is smaller than Rhode Island.

    So we read, for example, “Harvey Slams Into U.S.” in a British tabloid headline. Sounds like folks in Peoria better hunker down, right? Harvey “slammed” into Rockport, Tx. The rest of the U.S. was spared. There is a 30-mile-wide swatch of destruction from Harvey’s 125 mph wind field. But most of the damage in Texas was from flooding, which occurred elsewhere after the hurricane had devolved and was not related to wind strength. (And most of that damage was self-inflicted, the result of building subdivisions in the flood plains around Houston.)

    • You are correct that the worst occurs right in the eye wall, and that band is not much wider than the eye. However the eyewall-stories of super-hurricanes are horrific. Because they cannot say exactly where the path will be they need to evacuate a wider band.

      The area effected by storm-surge is far wider, and when the sea abruptly rises fifteen feet even “minimal hurricane” winds, farther from the center are deadly. People say “minimal hurricane” like it is a piece of cake. Try sticking your head out of the window of a car travelling at 75 mph and tell me how “minimal” it is.

      To return to eyewall-stories, the most freaky involved the Labor Day storm in the the Florida Keys in 1935, and a person picked up by a gust and carried away; corpse found miles away. The Keys were not evacuated on 1935 because they had no idea the hurricane would intensify as abruptly as it did, and only a vauge idea it was coming. I’m nervous because Irma is passing over the same very-warm waters, yet the NHC isn’t considering rapid intensification at the last minute, before hitting land.

      Reports from Andrew in 1993 give one the sense that the eyewall isn’t merely straight winds moving very fast, but twisting winds, at times like twining tornadoes on their sides. The good news is that the eyewall falls apart quickly over land. The bad news is that the storm-surge does not fall apart so quickly. When the 1938 hurricane charged north at over 50 mph to Long Island and New England in 1938 is winds had dropped to Cat 2 levels due to crossing colder waters, but the storm surge that hit seemed like a Cat 5 storm surge.

      I would not like to be the people in charge of warning others. They need to err on the side of caution, and that means the fortunate will be able to laugh, “It wasn’t as bad as they said.” But those who bear the brunt will have their lives saved if they heed warnings.

      .Hang in there, Florida.

      • In comparison to Irma the Labor Day Hurricane of 1935 was the most intense hurricane to make landfall in the US ever. Coming on shore in Florida as a Cat 5. Its pressure was much lower than Irma being the third lowest in history, and it winds were calculated to have been between 186.4 mph – 188.7 mph. Most interestingly it happened in 1935. May Florida not see its like again.

  9. Florida is roughly 440 miles long, not counting the keys. The max width of Irma is 370 miles, but hurricane force winds (>75MPH) only cover 150 miles. I predict, considering the closer approach to Cuba’s mountains, coupled with the significant overnight drop in windspeed of 20MPH, that Irma almost certainly will not be a Cat 4 upon landfall in Miami, or if it is, it won’t remain one for very long afterwards. This from an interested observer, not a hurricane afficiando.

    • I’ve read that Florida won’t diminish Irma much, because its ground is wet (due to recent rains, plus the Everglades) and flat.

  10. Number of websites are reporting that Irma has been downgraded to Cat 4. Proceed with extreme caution. (NHC @ 12.00 UTC : MAXIMUM SUSTAINED WINDS…150 MPH)
    Good news I hope, among all the gloom, doom and ‘the end of the world as we know it’.

  11. So here is an idea. I have been studying these types of laminar flows and I think that something can be done to disrupt hurricanes right befor they make landfall. So I thought I would present it here. I’m not sure if it will help with Irma because there are only two days to do this.

    The loss of wind power over land is caused by disruption of air flow along the surface of the earth. There is nothing to stop this flow over water and the heat of the water adds to the power. The central eye wall is the location of the greatest speed in a relatively thin laminar column of air. Maybe 2-5 miles wide. The MOAB ordinance has a significant power out to a mile radius. A sequence of MOAB explosions approximately 1 mile above the ocean surface at or near the surface of the inner wall would cause disruption of the air flow in a significant manner. This is a laminar fluid flow and pushing on it would cause the flow to change course. The wall would not be destroyed but the disruption would use the force of the moving air to cause the power to work against itself enough to lower the intensity of the hurricane as it makes landfall. The eye is only 30 miles wide. Disrupting the flow in one spot with a sequence of MOAB explosions at that location of the eye wall would impact the strength of the eye wall winds on a significant percentage basis.

    • Using MOABs occurred to me too. However, a MHAB has a total of 11 tons of TNT energy while Hurricane Irma currently generates 24 tons of TNT equivalent energy per second (110TJ at 3 pm September 8 Hurricane time).

      Note that the Hiroshima bomb had a yield of about 13 Kilotons.

      • I am not sure about the amount of energy being generated is relevant as the wind flow is nearly 100% inertial. The flow exists in laminar fields that are at there highest velocity in the wall, travelling aling the ground and entering the eye, turning upward and then out the top and back down to the ground where the air flows back in to the center.

        The flow upward being inertial creates the low pressure center that actually acts like a vacuum pulling in the air along the ground while the air is heated by the warm water adding energy to the flow. Again the flow is almost 100% inertial.

        Disrupting the flow in one concentrated spot will cause some of the inertial flow to enter the eye, and create turbulence that will dissipate some of the inertial energy. Sequencing explosions at a concentrated spot will then cause a cascade of energy dissipation into the eye and outward from the wall. The winds are the highest leaving the ground and the laminar flows are the thinest.

        I’m not sure where the sweet spot is above the ocean but disruption of the column of air WILL use the inertial forces tobdissipate energy.

      • A light rain fall over Washington DC releases as much energy as the Hiroshima bomb, in light of that human are relativity puny compared to nature. We are not the gods most liberals and so called educated think we are.

  12. It looks like Judy Curry’s CFAN forecast three days ago was pretty close. We will get another NHC update at 1400, but the current track is right up the west coast of the peninsula (Naples, Ft. Meyers, Tampa) with storm surge to 12 feet. Depending on where the eye is, we will probably have Cat 1 or 2 with storm surge of 5 feet. Moved the cars to interior of third floor garage (everybody else moved off the ground floor also.. All the ground floor entrances are now sand bagged despite being 10feet above MHT and with custom steel doors. Only remaining to do is water. That can wait to late tonight.
    Mandatory evacuation from Miami Dade a record, 680,000 people. Biscayne Bay and Miami Beach susceptible to significant storm surge thanks to topography.

    • … and guess what, my brother arrived in Fort L. just 4 or 5 days ago, they drove all the way from Canada during previous 3 days, didn’t want to turn back, then Irma was just a tropical storm, got keys for his newly purchased apartment, and decided to sit it out after purchasing $300 worth of emergency supplies.
      Building is concrete, second floor, now boarding the windows. Despite not making very wise decision, he use to be a very good engineer so hopefully in an emergency might do a right thing.

      • Depending on where their condo is, should be OK. Likely at most a Cat 1 here IF the present track holds. Should be quite an adventure for Canadians.

      • He served in the army, confronted Canadian snow and -20 to -30C Canadian winters for couple of decades, a bit of a macho-man, more likely to be looking forward to the challenge of it. They are about 3-4 miles away from the ocean in direction of Sunrise, so safe from any tidal surge.

    • My fear right now is that the eye will go out into the Gulf just along the coast and ride northward. If the eye does stay over the Gulf and rakes the coast line traveling north, well,it will be one hell of a ride. Fortunately my land elevation is 13 ft and my base floor is 15 feet. Shutters are up, supplies laid in, everything is ready. Will post again on the other side.

      • Stay safe in Venice. We will be fine over here in Ft. Lauderdale unless Joe Bastardi is right and Judy Curry wrong. He still has it on the Atlantic side. Lets hope Latitude evacuated. Long Key is on the dirty side of the current (1400 EDT 9/8) track and NHC forecast..

      • It is likely that Hurricane Irma storm surge hazard is being underestimated by the National Hurricane Center. hurricane-center-underestimating-irmas-storm-surge/

        This conclusion is backed up by a NHC SLOSH simulation of Hurricane Charlie yielded a maximum 18 ft storm surge at a Radius of Maximum Winds (RMW) of 30 miles at a simulated wind speed of 120 mph:

        Factors the increased storm surge were:
        (1) suction in the region of lower pressure raises the ocean height about 8 mm/millibar pressure drop;
        (2) rotational motion creating a lopsided donut of elevated water volume on the strong side of the hurricane. This volume is porportional to the square of the radius of the area of maximum winds (RMW);
        (3) The depth of moving water typically extends to 100 meters (328 feet) on the strong side of the storm. Once the hurricane hits shallow water the friction with the ocean bottom the deep water cannot carry away water piled up in the maximum wind region yielding the water surge (especially for faster moving hurricanes);
        (4) Waves add to the surge via wave setup due to waves piling water onto the shore faster than rip currents can drain it away. More important where deep water is less than 10 miles offshore as off the Florida coast.

        In view of the SLUSH model Hurricane Irma will likely result in a higher surge than the National Hurricane Center (NHC) predicts due to the following:
        (1) Pressures are reaching about 925 millibars:;
        (2) RMW are currently about 30 miles:;
        (3) Hurricane Irma is expected to become larger and reach landfall as a Cat 5 hurricane since it is approaching warmer waters (>30 degrees C
        (4) Wind shear is currently low at about 10 knots which should favor the storm’s organization
        (5) Hurricane forward motion is currently about 12 mph which may effect the surge height;
        (6) Tides (up to +3 ft) may add to the surge height depending on the time of surge arrival.

        Hurricane Irma is also currently large (150-200 miles radius), with a high wind speed (155 mph), yielding a current Integrated Kinetic Energy (IKE) of 110 terajoules (TJ) which corresponds to about 24 kilotons of TNT equivalent of energy per second, or 8.64 megatons per hour.

        The September 7th, the more accurate/robust CMWF European model shows the hurricane track to be on the Western side of Florida, which should mitigate these effects somewhat.

        If the CMWF model is correct this surge hazard reduction for the Florida coast will be due to a lower elevation donut of water and lower wave setup on the leeward side of the coast. The Florida Keys still gets the full surge big time.

        If, however, the US GFS more Eastern landfall model is correct the hurricane surge and wind damage for Florida will be much greater.

    • It looks like Judy Curry’s CFAN forecast three days ago was pretty close.

      So was it Dr Curry’s forecast or CFAN’s? Are we now allowed to take credit for the forecasts of others because we feature them on our blogs?

      (And can we quietly renounce or ignore all those many forecasts, whether from ourselves or others, which don’t happen to come to pass?)

  13. It will be interesting to see how many wind turbines and solar arrays are destroyed by this storm. Even with blades feathered these massive pylons produce a lot of drag, and are in danger of toppling. As has happened many times before…..


  14. A lot of thoughts and prayers around hoping and praying Irma will miss Florida. Well Florida is only about 100 – 125 miles wide so run-off only needs to go 50 – 60 miles max to get to the ocean. (I’ve excluded storm surge as there will be storm surge with any landfall.)

    Now consider the prayers to spare Florida and landfall occurs Carolina or northern gulf coast and moves inland. There will be storm surge and there will be heavy rain but much of the storms flooding will be delivered from areas up to a couple of hundred of miles away and in areas not designed/prepared for such weather events. It will hit the drainages in many cases back to the region of landfall.

    If you choose to live in Florida expect major storms. If you live in the northern states expect blizzards. If you live in the mid-Atlantic expect both, Mississippi river valley get their tornadoes. But why shouldn’t Florida take the hit and tame this nasty bitch rather than dumping it on someone else? They should expect it and be prepared.

    Hope, pray, or whine and cry, but weather comes with the territory. Just deal with it!

    • Actually, not just Florida, but anywhere on the Eastern Seaboard should expect hurricanes. The SE state, ie GA, SC and NC, can even expect powerful storms.

      Providence, RI built a surge barrier after the terrible hurricanes of preceding decades, but NYC didn’t, and paid the price when Tropical Storm Sandy came ashore at high tide.

  15. Hurricanes are simply not related to global warming, which by the way we’ve seen little of for a decade or so, if we indeed follow the narrative, this storm is technically been worsened by climate remaining about the same as it was 20 years ago! How do we figure that, Headline: “Cyclone Irma worsened by global sameness”. Nevertheless, they keep trying, but now just a reminder AGW for a doubling of CO2 (which we’ve not seen yet) is supposed to inclusive of feedbacks contribute 3.7 Watts per square meter, currently the imbalance is supposed to be 0.6W per square metre, so that means it adds around 0.6/1100 or 0.00054 (0.054%) to peak insolation at the equator, responsible for ocean warming. That’s about enough to turn a 915mb storm like Irma to a 914.95 mb storm. So this narrative cannot be justified by the energy. This storm is caused by the sun, and not the piddling energy that might (sorta kinda) be added by 0.6W per square meter of diffracted energy that hasn’t changed in the last decade!

    • We’ve seen little global warming for a decade or so??!!? Please tell that to the disappearing glaciers! We lived near the Columbian icefields for 10 years and witnessed the massive Athabasca glacier recede as much in the past ten years as it had done in the previous 100+ years.

      • None of which has anything to do with CO2 scattering 0.6 Watts per square metre either. There has been no significant measurable global warming for decades. All the emotive claptrap about glaciers and whatnot doesn’t change the fact that melting glaciers costs 344kJ per kg and 0.6Watts per square metre isn’t going to melt much. 0.6W per square meter is around 1 Christmas tree light in a square meter column of air 5km high above the glacier. Meanwhile, at the other end of the world the glaciers are growing.

  16. I did a calculation. At 2am EDT, the center of Hurricane Irma was 66.2 mi from Key West and it had increased intensity back to a CAT 4 with sustained wind speed of 130 mph. What is confusing is that, at the same time, the sustained wind speed in Key West was only 64 mph. With Irma being so large and so close to Key West, why isn’t the wind speed in Key West at LEAST at hurricane force of 74 mph?

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