Historical Tropical Cyclones, Reanalysis and Climatology Discussion

[LibertyBell]

21 hours ago, ncforecaster89 said:

Hi Liberty!  I’ve done a lot of statistical research into NATL basin activity via HURDAT2 and other historical sources.  These records seem to indicate that the recent apparent increase of major hurricanes (MH) during the month of October isn’t that unusual or even anomalous.  

Here’s an overview of the known October MH activity in the NATL basin since 1851.  It’s important to note that it’s highly likely...more like a certainty...that many other MHs are unaccounted for in the historical record prior to the satellite era, beginning in 1966. Moreover, it’s also most probable that a large number of the known hurricanes and major hurricanes likely had a higher peak intensity than presently listed in HURDAT2; especially the further it goes back in time.  With that in mind, I’m also listing all the conservatively estimated 90 kt hurricanes from 1851-1910 and the 95 kt hurricanes from 1911-2000.  The years highlighted in bold correspond to the seasons in which the strongest hurricane of that year occurred in either October or November (48 out of the 168 seasons since 1851). 

1852 = 90 kt; 1853 = 90 kt; 1858 = 90 kt; 1859 = 110 kt; 1860 = 90 kt, 90 kt 1865 = 90 kt; 1866 = 120 kt; 1867 = 110 kt; 1868 = 90 kt, 90 kt; 1869 = 90 kt; 1870 = 100 kt, 90 kt, 90 kt; 1873 = 100 kt; 1874 = 90 kt (NOV); 1875 = 90 kt; 1876 = 90 kt, 100 kt; 1877 = 100 kt; 1878 = 120 kt, 100 kt, 90 kt; 1879 = 90 kt (NOV); 1880 = 120 kt; 1882 = 120 kt; 1884 = 90 kt; 1886 = 105 kt; 1887 = 90 kt; 1888 = 95 kt; 1893 = 105 kt, 115 kt; 1894 = 105 kt, 115 kt, 95 kt; 1895 = 90 kt; 1898 = 115 kt; 1899 = 95 kt; 1902 = 90 kt; 1905 = 105 kt; 1906 = 105 kt; 1908 = 95 kt, 90 kt; 1909 = 105 kt, 90 kt (NOV); 1910 = 130 kt;  1912 = 100 kt (NOV); 1916 = 105 kt, 95 kt; 

1921 = 120 kt; 1922 = 95 kt; 1924 = 145 kt; 1926 = 130 kt; 1932 = 150 kt; 1933 = 110 kt; 1934 = 100 kt (NOV); 1939 = 120 kt;  1941 = 105 kt; 1942 = 95 kt (NOV); 1943 = 95 kt; 1944 = 125 kt; 1947 = 105 kt;  1948 = 110 kt; 1949 = 95 kt; 1950 = 95 kt, 100 kt, 115 kt; 1952 = 125 kt; 1954 = 115 kt; 1955 = 95 kt; 1959 = 105 kt; 1961 = 110 kt, 140 kt; 1962 = 95 kt, 100 kt; 1963 = 125, 95 kt;  1964 = 130 kt, 110 kt; 1966 = 130 kt; 1975 = 120 kt; 1985 = 105 kt (NOV); 1988 = 125 kt; 

1994 = 95 kt (NOV); 1995 = 130 kt, 110 kt; 1996 = 100 kt; 1998 = 155 kt (NOV); 1999 = 95 kt, 135 kt (NOV);  2000 = 120 kt; 2001 = 125 kt, 120 kt (NOV); 2002 = 125 kt; 2003 = 110 kt; 2005 = 160 kt, 100 kt; 2008 = 115 kt, 125 kt (NOV); 2011 = 120 kt, 100 kt; 2012 = 100 kt; 2014 = 125 kt; 2015 = 135 kt; 2016 = 145 kt, 120 kt, 100 kt; 2017 = 100 kt; 2018 = 140 kt.

As can be ascertained from these data, the seemingly increases in late-season/October MH frequency is more the result of much improved detection and verification of such storms, as well as a recency bias.  The biggest takeaway for me is the realization that a very significant number of NATL basin major hurricanes occur after 9/30.        

Very interesting, so there hasn't been some sort of cyclic or pattern change that would cause this! How far back would you say that the HURDAT2 list is reasonably accurate, both on quantity and intensity?

 

[Fishwrap]

King in 1950 was an interesting one.  Almost a huge tornado.  I experienced the eye almost dead center.  It was completely calm.  People were lighting matches and holding them up and they did not blow out.  In others I've been in there was some air movement in the eye.  The match trick would not have worked.

[ncforecaster89]

On 5/6/2019 at 6:19 PM, LibertyBell said:

Very interesting, so there hasn't been some sort of cyclic or pattern change that would cause this! How far back would you say that the HURDAT2 list is reasonably accurate, both on quantity and intensity?

 

Given that the majority of major hurricanes develop in the western Caribbean, during the month of October, the warm phase of the ENSO cycle is most influential in suppressing such activity...while the cool or neutral phase doesn’t have as profound of an effect.  Moreover, the warm phase of the AMO is a significant driver of increased activity in the NATL basin throughout the season...to include the late season months of October and November.    

The beginning of the satellite era (1966 onward) is the point of delineation for me in determining the period whereby HURDAT2 is most reasonably accurate.  Prior to that time, without satellite surveillance, it is a virtual certainty that many TCs (to include major hurricanes) went undetected, and many others’ intensity was likely underestimated; especially the further we go back in time.  Of course, my definition of what characterizes being “reasonably accurate” might have a higher threshold than others...where some may consider the beginning of Recon flights in 1943, being a more reasonable standard in that regard.    

As you noted previously, more recent records indicate that the mainland USA experiences a category-five hurricane roughly every 30 years, on average.  As such, it’s highly likely that there were additional category-five hurricane landfalls (at least 1 or 2) prior to the 1935 Great Labor Day hurricane...despite HURDAT2 showing no such occurrences for at least the 85 year period from 1851-1935.    

[LibertyBell]

20 hours ago, ncforecaster89 said:

Given that the majority of major hurricanes develop in the western Caribbean, during the month of October, the warm phase of the ENSO cycle is most influential in suppressing such activity...while the cool or neutral phase doesn’t have as profound of an effect.  Moreover, the warm phase of the AMO is a significant driver of increased activity in the NATL basin throughout the season...to include the late season months of October and November.    

The beginning of the satellite era (1966 onward) is the point of delineation for me in determining the period whereby HURDAT2 is most reasonably accurate.  Prior to that time, without satellite surveillance, it is a virtual certainty that many TCs (to include major hurricanes) went undetected, and many others’ intensity was likely underestimated; especially the further we go back in time.  Of course, my definition of what characterizes being “reasonably accurate” might have a higher threshold than others...where some may consider the beginning of Recon flights in 1943, being a more reasonable standard in that regard.    

As you noted previously, more recent records indicate that the mainland USA experiences a category-five hurricane roughly every 30 years, on average.  As such, it’s highly likely that there were additional category-five hurricane landfalls (at least 1 or 2) prior to the 1935 Great Labor Day hurricane...despite HURDAT2 showing no such occurrences for at least the 85 year period from 1851-1935.    

Thanks, it makes me wonder how many storms and canes we actually had in 1933, the record which was overtaken by 2005.  It's possible that 1933 had more if the records from back then are that incomplete!

 

About the AMO, I wonder if that cycle is of variable length, it seems like the earlier periods of the warm phase were somewhat dissimilar from each other (1950s-1960s), (1990s-2000s), etc.

 

 

[Floydbuster]

On 5/7/2019 at 9:02 PM, ncforecaster89 said:

Given that the majority of major hurricanes develop in the western Caribbean, during the month of October, the warm phase of the ENSO cycle is most influential in suppressing such activity...while the cool or neutral phase doesn’t have as profound of an effect.  Moreover, the warm phase of the AMO is a significant driver of increased activity in the NATL basin throughout the season...to include the late season months of October and November.    

The beginning of the satellite era (1966 onward) is the point of delineation for me in determining the period whereby HURDAT2 is most reasonably accurate.  Prior to that time, without satellite surveillance, it is a virtual certainty that many TCs (to include major hurricanes) went undetected, and many others’ intensity was likely underestimated; especially the further we go back in time.  Of course, my definition of what characterizes being “reasonably accurate” might have a higher threshold than others...where some may consider the beginning of Recon flights in 1943, being a more reasonable standard in that regard.    

As you noted previously, more recent records indicate that the mainland USA experiences a category-five hurricane roughly every 30 years, on average.  As such, it’s highly likely that there were additional category-five hurricane landfalls (at least 1 or 2) prior to the 1935 Great Labor Day hurricane...despite HURDAT2 showing no such occurrences for at least the 85 year period from 1851-1935.    

 

Well, according to the re-analysis project, there are several Category 4 storms close to Category 5 strength at landfall:

Pre-records: 1846 Hurricane may have been at Cat 5 intensity near Florida Keys.

August 1856 - "Last Island" - 150 mph/934 mb

August 1886 - "Indianola" - 150 mph/925 mb

 

[ncforecaster89]

On 5/9/2019 at 8:03 AM, Floydbuster said:

 

Well, according to the re-analysis project, there are several Category 4 storms close to Category 5 strength at landfall:

Pre-records: 1846 Hurricane may have been at Cat 5 intensity near Florida Keys.

August 1856 - "Last Island" - 150 mph/934 mb

August 1886 - "Indianola" - 150 mph/925 mb

 

You're reading my mind, as those are precisely the top candidates for most likely category-five hurricanes USA landfalls  whose intensity was underestimated.  Those aside, others listed in the early HURDAT2 records could've been underestimated due to lack of data, as well.  The 1846 hurricane is one that has always fascinated me as a probable category five.   

Edit: Just realized the typo for the date of the hurricane referenced in the last sentence (meant the 1846 hurricane; not 1842).  

[Windspeed]

November 2019 - The 1961 to 1965 Atlantic hurricane seasons have been reanalyzed. Revisions to the hurricane database were accomplished by obtaining the original observations collected - mainly by ships, weather stations, the Hurricane Hunter Navy, Air Force, and Environmental Science Services Administration (ESSA) aircraft reconnaissance planes, and the earliest available satellite images - and assessing the storms based upon our understanding of hurricanes today. The reanalysis also allowed "discovering" of tropical storms and hurricanes that occurred, but were not yet officially recognized as such in the official records. Nine new tropical storms and hurricanes during these five years were discovered and added to the database. Six hurricanes were identified as impacting the United States, one less than originally identified. The hurricane with the worst impact for the United States during these seasons was Betsy in 1965, which killed 75 people in Florida and Louisiana and was the first ever billion dollar hurricane for U.S. damage.  Betsy was upgraded to a Category 4 from a Category 3 hurricane on the Saffir-Simpson Hurricane Wind Scale at landfall in Louisiana, as it is reassessed that it had maximum sustained surface winds of 115 kt (130 mph) and a central pressure of 946 mb. Sandy Delgado, Brenden Moses, Andrew Hagen, Chris Landsea, and the Best Track Change Committee all made substantial contributions toward the reanalysis of these hurricane seasons."

https://www.aoml.noaa.gov/hrd/data_sub/re_anal.html

Of note, aside from the upgrade of Betsy to a Cat 4 as noted above, Carla is also now a confirmed Cat 4 landfall into Texas. Haiti was hit by two Cat 4 hurricanes within two years in Cleo ('64) and Flora ('63). Belize was also impacted by a Cat 4, Hattie, '65.

Full report can be found here:
1961-1965 revisions

[ncforecaster89]

10 hours ago, Windspeed said:

 

https://www.aoml.noaa.gov/hrd/data_sub/re_anal.html

Of note, aside from the upgrade of Betsy to a Cat 4 as noted above, Carla is also now a confirmed Cat 4 landfall into Texas. Haiti was hit by two Cat 4 hurricanes within two years in Cleo ('64) and Flora ('63). Belize was also impacted by a Cat 4, Hattie, '65.

Full report can be found here:
1961-1965 revisions

 

Don't typically disagree with their reanalysis, but I felt the available data justified a 100 kt Cat 3 designation for Dora 1964...at landfall in NEFL.  

Edit:  Thought I'd share a few links of historic footage taken during and/or after some of the hurricanes from the latest reanalysis period.

 

 

 

 

 

[HalloweenGale]

On 12/9/2019 at 1:10 AM, Windspeed said:

 

https://www.aoml.noaa.gov/hrd/data_sub/re_anal.html

Of note, aside from the upgrade of Betsy to a Cat 4 as noted above, Carla is also now a confirmed Cat 4 landfall into Texas. Haiti was hit by two Cat 4 hurricanes within two years in Cleo ('64) and Flora ('63). Belize was also impacted by a Cat 4, Hattie, '65.

Full report can be found here:
1961-1965 revisions

I'm interested in that hurricane that had been left out of the database and was described as a "winter type storm."

[Windspeed]

Nice ERA-5 model reanalysis of Hurricane Hugo:

[Windspeed]

New paper by NOAA/OAR/AOML on the relationship between the Madden-Julian oscillation (MJO) and rapid intensification of tropical cyclones.

Important Conclusions: 

1.  Rapid intensification events and the MJO tend to move with each other from west to east across the hemisphere suggesting a relationship between the two.

2.  Rapid intensification is most likely to occur when the MJO is neither stormy and wet nor sunny and dry near the tropical cyclone.

3.  The addition of information about the MJO does not improve forecasts of rapid intensification.  This is likely because the information about the MJO is already available in the forecast models in a different form.

 

Klotzbach (2012), in their seminal study on the relationship between RI in the Atlantic and the MJO, found that RI is four times more likely during the active MJO phase than during the inactive phase. The current study extends this work to the Central and East Pacific and tests whether the MJO may have predictive capability in current forecast schemes. All RI events in the north/western hemisphere along with the two commensurate RMM modes (Wheeler and Hendon 2014) are compiled from 1974 to 2015. The events are compiled into 20-degree-wide bins, and the mean values in each bin show that RI events and MJO events tend to move in tandem with each other from west to east across the hemisphere. Unlike in the Klotzbach (2012) study, the MJO is not generally in the most active convective phase in the region when RI occurs. Though the mean magnitudes are small, the differences between many bins are statistically significant. However, the addition of this information to statistical RI forecasting schemes does not significantly improve forecasts from SHIPS-RII, possibly because the MJO is not related to RI itself, but instead to cyclogenesis, a necessary precursor to RI, or due to the large scatter in the RMM values.

Though the results here show a relationship between the MJO and RI events in the hemisphere, they do not show improvements to current operational RI-prediction models. Despite this, other techniques, such as those based upon machine learning or other artificial intelligence algorithms, might be useful to pursue in the future.

Paper can be obtained here.

 

Some additional thoughts of my own. Though clearly a favorable MJO or strong coupled Kelvin can help induce tropical cyclone genesis via an existing MCS, disturbace, wave, etc., there is clearly other factors at play with respect to an existing strong convectively coupled Kelvin and an already established TC going through RI. It may even be possible that a strong coupled Kelvin could create too much surrounding convection and competing micro regions of convergence that might limit low-level feed or interfere with the main vortex of an established TC. Also, since this paper focused on how currently existing RI models do not seem to benefit from additional MJO- Kelvin data, though an unfavorable MJO phase might deter RI, a favorable coupled-Kelvin doesn't necessarily increase existing parameters for RI of a potential TC. Essentially, though a convectively-coupled 200 hPa vorticity wave does greatly establish much better support of TCGs, it does not necessarily help in their RI phase if already mature, and that a neutral phase of the MJO might be the most conducive for RI of an existing TCG.

[Windspeed]

Short but nice article by NOAA about tropical cyclone scientist, Isaac Monroe:

Isaac Monroe Cline: The Cyclone Pioneer

[Windspeed]

Researchers find link between Atlantic hurricanes and weather system in East Asia

In a new study, the researchers say the East Asian Subtropical Jet Stream (EASJ) an upper-level river of wind that originates in East Asia and moves west to east across the globe, carries with it an atmospheric phenomenon called a Rossby wave.
Rossby waves occur naturally within the Earth's oceans and atmosphere, forming because of the planet's rotation. The researchers say Rossby waves hitch a ride on the EASJ to the North Atlantic when tropical cyclones in the Atlantic are most likely to form. The waves affect wind shear, a key element in the formation of tropical storms.
"When the EASJ is stronger, it can enhance this pattern, which leads to stronger teleconnections and stronger wind shear in the North Atlantic," explains says Wei Zhang, a climate scientist at IIHR-Hydroscience & Engineering at Iowa. "That can suppress Atlantic tropical cyclone formation."

https://phys.org/news/2020-08-link-atlantic-hurricanes-weather-east.html

[Windspeed]

[Windspeed]

[the ghost of leroy]

30 minutes ago, Windspeed said:

 

That would be a nice board meltdown if it were to happen again. 

[CheeselandSkies]

18 hours ago, the ghost of leroy said:

That would be a nice board meltdown if it were to happen again. 

Some of the GFS tracks in recent days haven't been too far off from that.