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Comments of and replies to the
National Hurricane Center Best-Track Change Committee
June 2003

   Replies to the NHC best track change committee comments are given
   in offset brackets. <...> - C. W. Landsea

Minutes of the best-track change committee meeting, 29 April, 2003
Members Jack Beven, Jim Gross, Brian Jarvinen, Richard Pasch, Ed Rappaport, 
and chair (Colin McAdie) present.					

The committee met to consider the second-revision changes submitted by 
Chris Landsea et al. for the period 1851-1910.  This set of changes 
discussed below are the Landsea et al. response to the "consolidated 
minutes" of 01 May 2002.   

For convenience, the following is organized by page number (added during 
discussion) of the 29 page response section of this installment.   Items 
without page number are additional comments discussed at that juncture 
during the meeting.   

General comments:	
A significant issue discussed below is changing the track file with 
insufficient, or no, data.   The committee is unanimous in its opinion that 
changes should not be made without the support of observations.   As noted 
below, the committee is aware of the origin and shortcomings of this dataset, 
hence our support for the reanalysis.  However,  for any particular case 
(that is, one lacking evidence) it is not clear that the assignment of 85 kt 
is unreasonable.   The histogram simply reflects the number of cases, 
decreasing in time, for which we have some indication of a hurricane, but 
nothing else. 
The committee has sought to be consistent in its request for data supporting 
any change.  Therefore, if a change from an 85 kt maximum (based on the 
absence of data) has made and overlooked on our part,  please do not change 
the existing data set.  This applies to the post-1886 era.  A specific 
example, also mentioned below, is 1892 #3.   

   < It is agreed that changes should not be made to the pre-existing 
     HURDAT (1886 onward) based upon lack of observational data.  An
     example where such a strategy would be inadvisable would be storm #3
     of 1911.  (We've been working on the 1910s recently, so this system
     immediately came to mind.)  For this hurricane, we could find no direct 
     observations of hurricane intensity or even tropical storm intensity 
     from the Historical Weather Maps, COADS ship database, Monthly Weather 
     Review or other sources.  One might be tempted to alter the intensity 
     of this system downward significantly.  However, its hurricane status 
     is not in doubt because of its well-recorded impacts at landfall in
     Nicaragua.  Thus no changes should be made to its intensity as this
     particular system was archived with a reasonable lifecycle in HURDAT to 
     match impacting the Central American coast with a Category 2 (85 kt) 

     Other systems, unfortunately, have more ambiguity as to what their 
     intensity was for a large proportion of their lifetime.  For storms
     of the 19th Century and early 20th Century over the open ocean, one
     almost always does not have enough data to ascertain with certainty
     what the true intensity is.  It comes down to evaluating the 
     available observations versus the educated first-guesses that 
     Neumann and Hope came up with in their digitization of Cry's track
     plots.  (The previous reply provided details by Neumann about how
     they came up with the rough estimates of intensity for many of the
     systems for the late 1800s.  In that writeup, he describes how for
     the large majority of the systems that they simply quantified the
     peak intensity of systems as either 50 kt (tropical storm), 85 kt
     (minor hurricane) or 105 kt (major hurricane) and then developed
     reasonable lifecycles to match this somewhat arbitrary peak.) 
     However, as stated earlier, it is agreed that it would not be 
     advisable to make changes to the intensity of existing storms and
     hurricanes when there is insufficient data available.  Therefore, we
     have re-evaluated the systems mentioned in this set of minutes below 
     as well as all of the ones identified as problematic because of a 
     lack of data in the first round of comments from the committee in 
     2002.  These systems are the following:  1887 #16 becoming #18, 
     1889 #1, 1891 #2, 1891 #10, 1892 #2, 1892 #3, 1893 #5, 1895 #4, 
     1896 #6, 1898 #1, and 1899 #4.  For some of these tropical cyclones,
     observations were found to substantiate alterations made to the 
     intensity.  However, a few (i.e., 1892 #3, 1893 #5, and 1896 #6)
     were so lacking in data that no changes are now made to the intensity.
     In either case, all available observations of gale force or greater
     winds (or the equivalent in sea level pressure) are listed in full
     in the metadata file.

Specific comments: 
page 1.   It was noted in the consolidated minutes that the ATCF fix file 
uses a 4-digit year.  If this format were used by Landsea et al. it would 
allow TPC to import the file directly into the ATCF.   Is it possible for 
Landsea et al. to make this change? 

   < Yes, however, the center fix file needs to have substantial revisions
     before it is complete.  This will be focussed upon after the primary
     changes to HURDAT, the metadata file, the reply to comments and the
     track maps are finished. >

page 4.   1855 #1 was discussed, and is now accepted as revised.

page 5.   There was further discussion about the applicability of the Fujita 
scale in assessing damage caused by tropical cyclones, especially in this 
era (1860's).   If Landsea could provide a copy of Boose to Jim Gross, it 
would be appreciated.  Jim will examine the methodology and summarize for the 

   < These papers will be provided.  Additionally, Boose maintains a web site
     that contains all of the wind-caused damage descriptions as well as
     his analyses at: .
     See the "Landscape and Regional Impacts of Hurricanes in New England"
     (HF011) and "Landscape and Regional Impacts of Hurricanes in Puerto 
     Rico" (HF012) sites in particular. >

page 6.   1870 #6  A question was raised about the availability of the data 
used by Perez.  Is Perez (2000) in final form?   (Note to committee: we do 
have a manuscript copy of Perez.  In the Perez summary for 1870 #6, for 
example, other sources are referenced - these contain the actual data, or 
accounting of events.  Landsea's response on the bottom of his page 7 
concerning 1882 #7 also addresses this issue)

page 8.  1885 # 2. This is a typo in the consolidated minutes, and should be 
1895 # 2.  Explanation for shifting this track into Mexico is accepted.   
Additional note:  committee needs to obtain a copy of Ellis. 

   < A copy of the report by Ellis will be provided. >

pages 8 - 11   There was further discussion about the "lack of evidence" 
issue, and the response of Landsea et al.  There has been a valuable 
addition of background material to the record, especially concerning the 
digitization of Cry.  The committee is aware of the highly stratified nature 
of the early data, the "ballpark" intensities, and the reasons for their 
being so.  The essential point remains, given all of this, that changes must 
be made based upon observations, or reinterpretation of observations,  using 
documented methodology.  (see, for example, 1887 #16 becoming #18, 1889 #1, 
1892 #2, #3)

   < Agreed.  As described above, all of these systems and several more are 
     now re-analyzed accordingly. >

page 11.   1886 #4  Accepted as revised.  

page 12.    1887 #3  Thank you for clarifying the source of observations as 
Partagas, unless otherwise noted.    The committee suggests that this 
convention be highlighted early in the document for the benefit of future 

   < This is now so stated in the introduction of the metadata file. >

page 14   1887 #16 becoming #18.    In this case, P+D did not introduce any 
changes from Neumann et al.  Landsea et al., however, have "reduced the winds 
for whole lifecycle of the storm since the best available observations 
indicate that the system peaked as a minimal hurricane (65 kt chosen as peak 
winds) rather than the standard category 2 (85 kt) intensity originally 
suggested in HURDAT."    
Based on the conventions mentioned above, we can assume these observations 
are in P+D.   It can thus be assumed that 65 kt was chosen as the peak 
intensity based on a ship observation, but this should be explicitly stated.  
The change must be tied to an observation.  It would not serve any purpose to 
duplicate at length P+D or any other source, and this is not requested, but a 
key observation upon which the peak is determined should be given.   It is 
noted that other storms with changes of comparable magnitude are accompanied 
by fairly significant data listings.    

   < Agreed that additional details and evidence needs to be provided to
     substantiate changes made.  This is now so done for this system and some
     alterations from original re-analysis have been made. >

1887  Additional systems  #4   Given a surface pressure of 29.68 inches 
(apparently a good observation) in [the data uncovered by Michael 
Chenoweth], this system was a tropical storm and should be included as a 
single point storm.     

   < Additional information provided by Michael Chenoweth indicates that
     these values are surface pressures, not sea level pressures.  The
     height of the observations was about 30 m.  Thus the true sea level
     pressure value was closer to 1008 mb, rather than 1005 mb.  It
     still appears that the evidence for this system is inconclusive for
     tropical storm intensity, though it certainly was of at least 
     a tropical depression. >

page 14  1888   #3  Based on discussion and comment from BRJ, increase peak 
winds to 110 kt.  This would also be more consistent with keeping system as a 
"high end Category 3" as stated.  

   < Agreed.  So changed. >

page 15  1889   #1  Another case similar to 1887 #16 becoming #18.   Is the 
reduced peak intensity based on one observation, or many?  Is the remainder 
of the track determined by this peak, or are there other observations at 
other times?  Are there observations on 5/18-19 to justify the reduction in 
winds?  There is strong consensus that this should be explicitly stated.  

   < Specific observations are now explicitly included into the metadata 
     writeup to support changes made to HURDAT.  For this case in 
     particular, the 1889 Monthly Weather Review was very helpful in 
     providing guidance as to the intensity for much of the lifetime of 
     the hurricane. >
page 15.  1889  #3   Although accepted as revised, the consensus is that the 
end of the track still seems odd, given the populated coastline.  There is 
no readily apparent physical explanation for the sudden demise, and thus 
this portion of the track may need further work in the future. 

   < Agreed. >

page 16.  1891  #7 #8 #9.   The committee appreciates the additional time and 
effort that has gone into this proposed reduction in systems from 3 to 1, and 
notes that COADS is a valuable additional source of data.   In this case, 
however, the committee finds that COADS is not compelling.   The committee 
considered keeping revised track #7 and also keeping #8 and #9, but revised 
#7 incorporates pieces of #8 and #9, thus this would not be a good solution.  
There are multiple scenarios that could explain the data.  Further, there are 
no observations in Florida that support any tropical cyclones, complicating 
the issue.   The committee continues to acknowledge uncertainty in the 
disposition of these systems, but for now retains Neumann et al.  (Additional 
notes:   There is no mention of Perez in the meta data.  Can he provide 
anything here?)   

   < It is certainly true that the situation remains ambiguous at many times
     for these three systems.  However, portions of the existing tracks 
     cannot be correct given the information uncovered from COADS, such as 
     storm 8 on the 6th and storm 9 on the 10th and 11th.)  However, it is 
     agreed that the most prudent course of action at this point is to 
     table any action on these three storms, until additional station data
     can be obtained.  Thus efforts will be taken to obtain observations
     from Cuba as well as to search the archives for U.S. stations at the
     National Climate Data Center.  This will be conducted over the next
     few months. > 

1891  additional system #1 (July)    MWR mentions 'gale' winds.  This system 
may warrant further research.  Is there any COADS?

   < Agreed that this system deserves further investigation.  COADS and
     other data will be analyzed over the next few months. >

1891  additional system #4 (Sept)   MWR gives TS force winds at coastal 
stations.  This system is also given a high probability by P+D, and bears 
further investigation. 

   < Agreed that this system deserves further investigation.  COADS and
     other data will be analyzed over the next few months. >

page 17  1892  #2  Extratropical transition accepted, however, reduction to 
65 kt does not appear to be supported.

   < All gale force and greater observations available for this system 
     are now listed in the metadata files.  These observations support 
     the system peaking near minimal hurricane status, rather than the 
     standard Category 2 (85 kt) originally found in HURDAT. >

page 17  1892  #3  There appears to be minimal evidence, at best, for 
changing anything here.   If an observation cannot be referenced, do not 

   < It is agreed that there should be no changes made to the original
     intensity estimates found in HURDAT for this system, due to lack
     of observations. >

Note caption error in 1892 plot for system  #5.

   < So corrected. >

page 18  1893  #6   Committee previously requested opinion of BRJ on this 
storm.  His opinion did appear in the previous minutes, however, he has 
continued to work on this storm and now has a substantial revision.  He has 
agreed to present this to the committee when complete. 

page 18  1893  #6   If manual changes to the plotting program are required, 
please ensure that the resulting plot depicts the points as given in the 

   < Agreed.  This has always been the policy.  The manual changes to the
     intensity indicated has been to correct the hourly interpolation 
     produced by our software for some of the cases near or after landfall. >

page 18  1893  #10  There appears to be a timing error in this track.   
JLB will provide revised points. 

   < J. Beven further clarified that this was a timing error in the central
     pressure listed at 12 UTC on the 2nd of October.  This value was
     measured at 1530 UTC on the 2nd.  Given that HURDAT includes central
     pressures within +/-2 hours of the synoptic time, this value is now
     removed from HURDAT.  However, it is still included in the metadata
     file as well as the U.S. landfalling hurricane table. >

1898 - note possible additional system.  Significant rainfall in Jamaica 
found in MWR. No wind data, but a pressure is given of 28.66.   (May 23-27). 

   < Agreed that this system deserves further investigation.  COADS and
     other data will be analyzed over the next few months. >

page 22 1899 #6, becoming #8 - wording  -  system formed to the south of 
Jamaica, not the west. 

   < Changed wording as suggested. >

page 22 1900 #1  It is noted that some additional information may be 
gleaned from a publication of Isaac Cline's brother.   (JLB for details)

page 23  1901 #3  This is a typo in the consolidated minutes.  It pertains 
to 1903 # 3.   Although accepted as revised, the issue was that any 
statistical mean, or fit of data, obviously results from a population of 
points.   Thus, some outliers may be acceptable (and realistic) if the 
data seems to indicate that such is the case.   Also, the committee wishes 
to warn against a false sense of precision in using Ho's RMW estimates.    

   < Agreed. >

page 24  1903 #2   Discussed and accepted.  

page 24  1903 #3   Previous minutes had requested the opinion of BRJ, and 
this is still pending.  Decision pending on this system.  Committee notes 
that center should be over Nassau at 00 UTC, so work is required on the 

   < Agreed that the center needs to be moved to be close to Nassau at 
     00 UTC on the 10th.  However, the observations of east winds shifting
     to increased south winds at the time of lowest pressure suggests that
     the center went just to the west of Nassau, not over.  Track changed
     accordingly. >

page 24  1903 #8  Discussed and accepted. 

1903  Additional system #1   Block Island and Nantucket observations 
suggest tropical storm force winds, although the structure of the system 
is not clear.  Needs further research. 

   < Agreed that this system deserves further investigation.  COADS and
     other data will be analyzed over the next few months. >

1903  Additional system for 10-11 Sept.  A possible depression in the 
Gulf of Mexico.  Isaac Cline states that warnings were issued.  System not 
noted in P+D.   Needs further research. 

   < Agreed that this system deserves further investigation.  COADS and
     other data will be analyzed over the next few months. >

page 26.  1906 #5 becoming #6.  Provisionally accepted, although it may 
need more work. 

page 26  1906  #7  becoming #8    By analogy with H. Andrew, why would we 
reject the unofficial surface pressures given in the Miami Daily 
Metropolis?  This is how observations were solicited after Andrew, and 
the unofficial Fairbank's observation was considered a key piece of 
information.  What is the difference here?  Also, the Ho RMW values are 
estimates, and are not always correct.  Note that Barnes suggests a small 
core (~10 n mi may be a better estimate.)  

   < Agreed that these unofficial pressures should be utilized and are
     now incorporated, along with a revised estimate of RMW from Barnes'
     description, into the revised HURDAT.  Note that the changes now
     bring the hurricane up to a Category 3 (105 kt) at landfall in south
     Florida, which does agree with Partagas' assessment as well. >

1907 additional system #1   This system bears re-evaluation in light of 
Ana (2003).  There is no doubt of 35 kt winds, but the structure is not 

   < Agreed that this system deserves further investigation.  COADS and
     other data will be analyzed over the next few months. >

1908 additional system #2   It is noted that Isaac Cline felt that 
warnings in the Gulf were justified for this system.   

   < Agreed that this system deserves further investigation.  COADS and
     coastal station data will be analyzed over the next few months. >

page 27  1908 #6 becoming #7.   After much further discussion, the 
consensus is that it remains extremely unlikely that this system could 
have re-strengthened to Category 2 prior to landfall in eastern Cuba.  If 
anything, weakening would be expected, rather than strengthening, so this 
is not accepted as a plausible solution.   

   < Agreed.  The system is reduced back to a Category 1 hurricane at
     landfall in Cuba. >

page 28  1909 #5 becoming #6 The committee cannot accept this landfall 
intensity in Cuba, given topographic interference.   A rule-of-thumb 
would be to weaken the system two categories, rather than strengthening.

   < Agreed.  The system is reduced back to a Category 1 hurricane at
     landfall in Cuba. >

page 28  1909 #7 becoming #8.  Please check the plot of this system.

   < Plot of this hurricane has been checked and small changes have 
     been made to its track near landfall in the United States. >

page 28  1909 #9 becoming #10.  The crucial question here is whether the 
middle Keys were in some portion of the eye.   Given the close call, the 
decision is to leave this hurricane as a Category 3.  Implied precision in 
reducing to a Category 2 is not warranted.  Also note while some changes 
in intensity are small,  there are some very large reductions in intensity 
(30 kt) in the early part of the track. The text does not make this 

   < Agreed and so revised on both points. >

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