2017 TCRs

[CyclonicFury]

I don’t agree with this. As Alyono has said before, in the deep tropics, flight level winds often are equal or even greater than the surface winds. If NHC really wants to blend flight level winds and surface winds, they should stay consistent. For instance, should Hurricane Matthew have peaked at 135 kts since flight level winds only supported an intensity of 120-125 kt?

[NotoSans]

From what Eric Blake has said in Twitter, it seems that the NHC started to doubt the realiabiliy of SFMR estimates in extreme conditions last year. I do agree that NHC may need to revisit storms over the past few years, in particular Matthew, to ensure consistency in intensity estimates. I do also agree that there’s still a lot for us to learn regarding TC intensity, from different flight level to surface winds ratios to whether SFMR is realible.

[1900hurricane]

I don’t agree with this. As Alyono has said before, in the deep tropics, flight level winds often are equal or even greater than the surface winds. If NHC really wants to blend flight level winds and surface winds, they should stay consistent. For instance, should Hurricane Matthew have peaked at 135 kts since flight level winds only supported an intensity of 120-125 kt?

Possibly, but those issues haven't been called into question until recently. The SFMR algorithm was tweaked a couple years ago to more accurately estimate lower end tropical storm winds, but an unintended side effect is that it possibly altered the estimation of winds above 125 kt or so due to the small number of observations of those winds. That possible issue has been revealed this year due to the larger number of observations of these winds with Hurricanes Irma, Jose, and Maria.

 https://twitter.com/pppapin/status/972265251151499265




 https://twitter.com/EricBlake12/status/972271549012201472

[cycloneye]

Chaser Josh Morgerman has some issues with the part of report of Irma in Naples.

@iCyclone
My video from #Hurricane #IRMA in #Naples #Florida. NHC report says peak winds in Naples (81 knots gusting to 123) happened 4 pm, but at my location you can see most violent winds happened ~4:25-4:45 pm, with especially extreme gust at 4:42 pm. See here:

 https://twitter.com/iCyclone/status/973229030013943808

[cycloneye]

Another chaser cries foul on another area (Culebritas) measurment that is not on report.

@JMGarciaRivera
Reading the #HurricaneIrma report, and wondering why @NHC_Atlantic didn't include the report of 82kts G104kts from that very station in Culebrita.



 https://twitter.com/JMGarciaRivera/status/973258595457486848

[CrazyC83]

I am seeing a few issues with the TCR as well. The graphic doesn't show it weakening to cat 2 briefly after leaving Cuba (which the BT does) before the restrengthening. Operationally they only lowered it to 110 kt, but I knew the data didn't support such and the BT seems accurate at that time (certainly no more than 100 kt, and you could argue as low as 90 kt). Of course, the NHC is so bombarded right now that may have been oversight...

Interesting the SFMR just before Keys landfall was 119 kt - there could be a case for a 120 kt landfall intensity but that may be too high due to shoaling (I believe it was 108 kt before reprocessing, which would have supported a 110 kt intensity). Interesting that the Recon data fell off a cliff before final landfall, I wonder if that was because the strongest winds were overland in the marshes? The basis for the 100 kt landfall intensity was a storm chaser report, which is about 10 kt higher than supported by Recon, but it is certainly possible that stronger winds were in the middle of the Everglades unnoticed.

[cycloneye]

Good point by him.

@JMGarciaRivera
It'll be interesting to see if @NHC_Atlantic applies the same methodology & reasoning for their #HurricaneMaria intensity @ #PuertoRico. Some blending would yield 125-130kts @ landfall, as SFMR (FL) peak winds were 116kts (146kts), FL winds reduce to ~131kts. From #Irma report:



 https://twitter.com/JMGarciaRivera/status/973283148464345089

[Ptarmigan]

I am surprised to see Irma weakened to 155 knots of 180 mph.

[CrazyC83]

Many countries have released their reports for impacts in 2017 to be submitted to the WMO meeting next month.

http://www.wmo.int/pages/prog/www/tcp/HC-40.html

Re: Irma, a site on Anguilla reported a 10-min sustained wind of 165 kt (which would translate to a 1-min wind of about 183 kt). That was likely not reliable though.

[Kingarabian]

Would this new methodology by the NHC affect Patricia's max wind speed?

[CrazyC83]

Would this new methodology by the NHC affect Patricia's max wind speed?

Probably not. The FL winds in Patricia peaked at 192 kt (on both flights), which translates to 173 kt. The SFMR was 182 kt - blend them gets 178 kt. They still support well the intensities of 180 kt on both flights (185 kt between flights). If the SFMR was taken at face value, you could argue for 185 kt on the flight and 190 kt as a peak between flights. Dvorak estimates also supported extreme intensities (the ADT was T8.4 at peak, while the subjective ratings were unreliable due to constraints).

[1900hurricane]

I think Patrica '15 (and Joaquin '15) occurred before the change in algorithm just based on the Twitter conversation between Eric Blake and Philippe Papin, but I don't actually know precisely when it took place. "Two years ago" sounds like between the 2015 and 2016 seasons, but that's my interpretation of it. It also appears that SFMR ran a little high early on in Patricia's life based on some posts from the Patrica thread, which also makes me think the older algorithm was still in use at that time.

[Alyono]

Many countries have released their reports for impacts in 2017 to be submitted to the WMO meeting next month.

http://www.wmo.int/pages/prog/www/tcp/HC-40.html

Re: Irma, a site on Anguilla reported a 10-min sustained wind of 165 kt (which would translate to a 1-min wind of about 183 kt). That was likely not reliable though.

what elevation was that 10 minute 165 kt reading?

I do question that reading though. I would expect far more fatalities there had those winds occurred, despite the concrete and steel construction. That is basically a sustained EF5 tornado

Now, that said, perhaps Tornado Alley should consider all new construction having to be of that from the NE Caribbean as there were far fewer deaths there than would occur in the USA from those winds

[CrazyC83]

Many countries have released their reports for impacts in 2017 to be submitted to the WMO meeting next month.

http://www.wmo.int/pages/prog/www/tcp/HC-40.html

Re: Irma, a site on Anguilla reported a 10-min sustained wind of 165 kt (which would translate to a 1-min wind of about 183 kt). That was likely not reliable though.

what elevation was that 10 minute 165 kt reading?

I do question that reading though. I would expect far more fatalities there had those winds occurred, despite the concrete and steel construction. That is basically a sustained EF5 tornado

Now, that said, perhaps Tornado Akkey should consider all new construction having to be of that from the NE Caribbean as there were far fewer deaths there than would occur in the USA from those winds

The report doesn't say, but it likely wasn't too high. I think that would require investigation since that could have been equipment issues.

[NotoSans]

Many countries have released their reports for impacts in 2017 to be submitted to the WMO meeting next month.

http://www.wmo.int/pages/prog/www/tcp/HC-40.html

Re: Irma, a site on Anguilla reported a 10-min sustained wind of 165 kt (which would translate to a 1-min wind of about 183 kt). That was likely not reliable though.

Just had a look at the season summary prepared by the NHC. Looks like Maria's intensity for the Dominica landfall has been increased to 145 kt. Peak intensity and the intensity for the Puerto Rico landfall remain at 150 kt and 135 kt, respectively. Not sure if they are final estimates though, because the summary seems to contain a lot of errors at the moment.

While situated in an environment of warm sea surface temperatures and light vertical shear, the hurricane strengthened extremely rapidly. Maria became a 100-kt major hurricane by midday on September 18, and just 12 hours later, as it neared Dominica, it became a category 5 hurricane with maximum winds of 145 kt.
Slight weakening had occurred due to the mountains of Dominica, but the hurricane soon regained intensity and strengthened to its peak intensity of 150 kt around 0300 UTC September 20 while centered about 30 miles south of St. Croix. At that time, Maria had a minimum pressure of 908 mb, the lowest on record for the Atlantic basin east of 70°W.
Maria’s center crossed the southeast coast of Puerto Rico near Yabucoa around 1015 UTC September 20, and its maximum winds at that time were near 155 mph, which makes it the strongest hurricane to hit that island since 1928.

[CrazyC83]

One thing I am wondering is if the $50 billion US damage estimate for Irma includes, or excludes, Puerto Rico and the US Virgin Islands? I know they combined had about $3.5 billion in damage.

[Alyono]

I believe the 50 billion includes ALL US damage as NOAA has reported Maria's damage as well

Had Irma continued that west wobble any longer, San Juan would have had cat 5 conditions from Irma. Nearly the very worst case scenario

Also, I saw that Nate caused 225 million in US damage. It also was a hurricane in Mississippi. Kind of surprised Nate caused 225 million in damage

[wxman57]

I believe the 50 billion includes ALL US damage as NOAA has reported Maria's damage as well

Had Irma continued that west wobble any longer, San Juan would have had cat 5 conditions from Irma. Nearly the very worst case scenario

Also, I saw that Nate caused 225 million in US damage. It also was a hurricane in Mississippi. Kind of surprised Nate caused 225 million in damage

I don't think Nate produced any hurricane-force winds over land. In fact, I remember having a hard time finding TS winds along the MS coast. Main impact was from flooding.

[CrazyC83]

I believe the 50 billion includes ALL US damage as NOAA has reported Maria's damage as well

Had Irma continued that west wobble any longer, San Juan would have had cat 5 conditions from Irma. Nearly the very worst case scenario

Also, I saw that Nate caused 225 million in US damage. It also was a hurricane in Mississippi. Kind of surprised Nate caused 225 million in damage

I don't think Nate produced any hurricane-force winds over land. In fact, I remember having a hard time finding TS winds along the MS coast. Main impact was from flooding.

Any hurricane winds over land would have been limited to the extreme SE tip of Louisiana (uninhabited) and the beachfronts in eastern Harrison County, MS east of the eye (probably not sampled). Recon data (both FL and SFMR) supported a 70-75 kt intensity just 2 hours before landfall in MS, and it appeared to only fill slightly in that time. Out of respect of the lack of observations, I do estimate it weakened a bit in that last 2 hours, to 65 kt. It was probably 75 kt when it hit extreme SE LA.

I'm curious if Nate is upgraded to cat 2 in the Gulf at 12Z October 7 - I believe the highest FL winds were 90 kt (supports 81 kt) and highest SFMR was 84 kt. It's right on the borderline. The pressure at the time was 984 mb but it was moving very fast and quite small so that can't be a proxy against such.

[galaxy401]

Disagree slightly with the TCR report for Irma. It probably wasn't 160 knots while it rammed through the islands but it probably peaked at that intensity during some moments (such as over Anguilla). Maybe it will get revised again since several big reports have revisions in the future.

Don't know how I feel with their newer perspectives on SMFR winds. Need to see more of it before I can say for sure.