Windspeed

A new peer-reviewed study in the British Royal Meteorological Society journal Weather is proposing that Super Typhoon Haiyan is likely the most intense cyclone ever observed in the Satellite Era. They believe the center eye pressure peaked near 860 mb. http://onlinelibrary.wiley.com/doi/10.1002/wea.3045/full I have always argued that Haiyan remains the most intense cyclone we have witnessed in modern times. Had there been reconnaissance, no other cyclone's intensity data sets would top it. This paper puts that in perspective for me. I had no idea the station reading at Guiuan existed. Recorded 18 miles from center fix and measured to 910 mb, that observation is bloody insane! Even loosely estimating gradient, a center pressure of 866 mb is calculated. The authors settled on 861 mb and rounded to 860 mb based on a few variables. The eyewall had held a steady state in the 30 hrs following the last visible completion of an ERC. The coldest tower tops around the immediate wall were not warming at the recording of that surface pressure. The diameter of the eye had actually decreased slightly. Given Haiyan was positioned against the southern periphery of an amplified subtropical ridge (STR) at the time, imbedded in an above mean surface pressure regime, the pressure gradient most likely was not loose at that obs timestamp. They still did not go with the tightest gradient scenario however. The following is an excellent write-up by Bob Henson discussing the paper over at underground: This may all be semantics and the WMO may or may not take this new research into consideration for crowning Haiyan the most intense on record. But at least from a meteorological standpoint, that surface pressure ob is great evidence to support just why Haiyan's satellite presentation at that timestamp has no equal. Had there been a recon flight around that time, in my mind, the windspeeds would have no doubt been the strongest ever recorded in a tropical cyclone. Obviously, this is still speculation, but I believe it was at least 185 kts or equal to Major Hurricane Patricia. But given the surface pressure obs 18 miles from center fix and given the pressure environment, Haiyan may very well have had higher sustained winds. I realize It is difficult to fathom a 190-200 kts cyclone. But keep in mind, even though Patricia had a tiny core, it was imbedded in a surface trough. The hurricane was moving into a weakness by means of an advancing mid-to-upper trough and southwesterly steering regime. Haiyan's synoptic pattern contrasts significantly as the cyclone was imbedded within a moderate easterly steering flow against a strong mid-level ridge and higher surface pressures. Obviously, we will never know for certain Haiyan's peak windspeeds with the absence of reconnaissance. After considering all these factors and the new paper, however, I am confident Haiyan is the most intense system even if unofficial. To me it remains the Godzilla of tropical cyclones.

I like this system to undergo a period rapid intensification over the next 24-36 hrs into landfall. I think this makes landfall stronger than 80kts. Perhaps even reaches Category 3. The core is getting established and the upper environment is clearly favorable. 27-28°C SSTs should support sufficient enough instability given the divergence aloft and jetstreak to the north.

Heavy rains the past few days and issues with the spillway have put the Guajataca Dam under significant threat of failure. Placing this here as it's obviously still an aftermath issue by ol'Maria:

What the hell? https://www.buzzfeed.com/nidhiprakash/puerto-rico-cremations?utm_term=.ak8Bpg3PE#.jfRrwg4LW

^Likely. But the cyclone did inflict some horrific devestation and loss of life. It hit two major fleets and several large ports so fortunately plenty of details were logged that can be ironed out from a meteorological standpoint. Hopefully they don't spend the entire episode in Weenieville.

With respect to the recent impacts on the Lesser & Greater Antilles and US territories, PBS NOVA is airing a new documentary that focuses on the deadliest Altantic major hurricane in the historical record, The Great Hurricane of 1780. http://player.pbs.org/viralplayer/3005566471/

Here is a longer version with footage from the eyewall.

Here's a blast from the past: Anyone remember Major Hurricane Elena? It is another example of a hurricane that intensified significantly while over the shallow shelf waters of the northern Gulf. Elena reached upper Category 3 intensity with maximum estimated winds of 110 kts, but did weaken slightly to 100 kts in the hours just before landfall near Biloxi, Mississippi. I think we should realize, however, that Elena was its own worst enemy. It spent nearly four days in the same general region of the Gulf. The circulation took on slow and erratic movement ENE before looping sharply back to the WNW. This motion was due to interaction with a fast moving weak upper level shortwave trough that lifted and left Elena behind. The 500 mb weakness filled and allowed a ridge to take the wheel. Prolonged meandering and drift of the circulation likely did upwell cooler water from the previous days. This combined with the core's close proximity to the coast on its WNW track prior to landfall perhaps did prevent Elena from becoming a Category 4. The highest official coastal measurements were 92 kts sustained with 118 kts gust on Dauphin Is., Alabama, and gusts of 105 kts in Gulfport, Miss. Elena is also one of the few early and rare moments where a successful storm chaser was lucky enough to have a quality camera on the ground inside the eye at landfall. The chaser filmed the clear blue sky overhead and the beautiful concave eyewall seen @ 1m 20s. A stunning shot made even more impressive that this was captured in 1985.

115 kts ... massive wind radiii: Near or at landfall:

They can handle a Cat 2/3, yes, they have sea walls and well built structures. But that's besides the point. Even a Cat 2, don't take it seriously and it hits a densely populated area, see what happens. And just based on current motion, 15-20kt of weakening is probably close to the mark. It wouldn't be good and it will cause destruction. Nobody was hyping this. Edit: Current intensity is 125 kts and that may even be high. Earlier, when Lan looked a lot better, mind you, I made the 15-20 kt comment based on its appearance versus rapid forward motion. It's down to 125 kts. So give me the benefit of the doubt of 20 kts. You win. It will clearly weaken more than 20 kts. Probably 30 kts by landfall. Congratulations. I apologize for overhyping a 135 kt typhoon based on a worry of rapid motion. A Cat 2/3 landfall was forecast throughout and that is likely what it will be. Never called for anything higher, but you are correct. I insinuated hype with the word "worry" that it wouldn't weaken below Cat 3. It most likely will. Cheers!

That is your definition of hype? The core is in rapid motion. It's a worry vs I should just call it a windy day and move on?

Please quote me hyping this typhoon. Quote any words. I beg you. You are ridiculous.

I just do not see what your point is here. Who has made a call this will landfall as a Super Typhoon? Look at the forecast. It's still serious for Japan.

Also, NOBODY in this thread has been overhyping Lan. Not in the least. Get real.

Good thing that's not how we alert the public. You don't downplay a 135kt cyclone. Yes, the core may degrade to absolute crap by landfall. You want to base your advisory on that call. Have you ever been in a Cat 2/3 storm? This will be destructive. Hopefully it will weaken and that destruction will be mitigated.

Haha. That's clearly your opinion. I see this as a powerful system that is going to make landfalll in a densely populated region. All based on perspective I suppose.

Perhaps in 8-10 hrs, but the perspective that it's falling apart based on current satellite presentation isn't good sound meteorology. We all knew the system was going to weaken based on the environement. But Lan isn't exactly hot garbage.

Define "really going downhill"? If convection were falling apart, I'd concede. But this is classic tilting due to mid-level flow. Only, at present, the core is moving rapidly enough to counter it. That northern eyewall must still be quite fierce with such intense convection wrapped around it. Yes, you will have an assymmetrical appearance outside the core with baroclinic influence and increased southwesterly flow, but the core itself around the eyewall remains symmetrical and intact. This is still an intense typhoon. Hopefully it will begin to weaken significantly for the sake of impact on a highly populated region.

The center may be slightly tilted as well. Southerly flow is screaming. This is still an intense typhoon though. I am a bit worried this won't weaken more than 15-20 kts prior to landfall ue to rapid forward motion.

It's nice to have some recon surface obs for once in the WPAC to back up satellite estimates. I will say that Lan looks even better than it did when they acquired their dropsonde data yesterday. EDIT: ADT ranged from 5.9 to 6.3 during the time they would have been in the eyewall. At present, ADT CI # is: 6.8 / 922.9mb/134.8kt JTWC 21/2100 discussion:

I wonder if Lan will be intercepted by reconnaissance aircraft. Last year, there were several publications that members from Nagoya University and the Meteorogical Research Institute were going to conduct missions into powerful typhoons beginning this year. Granted, the 2017 WPAC season has been slow. But if ever there was a typhoon to start data gathering missions, especially considering the threat to Japan, you would think Lan would be it. https://weather.com/news/weather/news/typhoon-observation-western-pacific-recon-aircraft It would be awesome to have a dropsonde in this big powerful eyewall. Sometimes Dvorak underestimates large eyewalls. I recall Irma this year in the Atlantic was underestimated versus some of the recon measurements, though that hurricane was imbedded in a higher background pressure regime. Edit: Well I just stumbled across this info on another board. They did not include any obs but confirms the flight occurred. Article is Japanese, here is the Google translation: https://headlines.yahoo.co.jp/hl?a=20171020-00173308-nbnv-sctch

I agree that it is a little concerning that both majors have the core coming ashore left of Tokyo and Yokohama. That does increase right front surge potential for Tokyo Bay. But they do have a system of sea walls and dikes to handle tsunamis and surge, though the upper west portion of the bay could have issues if it surpasses 2-3 meters. It would still cause a lot of damage but hopefully not result in casualties. Worst cast would be the right side of the core running directly up the bay. The track would need to be exactly postioned and Lan has that potential. Still, even 40 hrs out, it could shift a bit. Let's see what 24 more hrs of modeling brings with interaction of the southwesterly flow at that positon. Hopefully the JMA is alerting the government and getting people in close promixity to the bay shoreline / water front aware.

I agree this has the potential to be a big hit for Japan. Though Lan won't hold this intensity, the fast movement will mitigate rapid weakening. This very well could be an upper end Cat 3 landfall for populated areas.

JTWC now up to 130 kts and forecast to peak at 140 kts over the next 12 hrs.

CI# /Pressure/ Vmax 6.1 / 941.1mb/117.4kt At this rate, it will be Super Typhoon Lan by 00z.