[Atlantic Oceanographic and Meteorological Laboratory]

HRD Home
About AOML
About HRD
Data Sets
 yellow triangle bulletMission Catalog
 yellow triangle bulletSfc. Wind Anal.
 yellow triangle bulletSyn. Surveillance
 yellow triangle bulletRe-Anal. Proj.
 yellow triangle bulletBasin-Wide Data
 yellow triangle bulletData Formats
Weather Info
What's New

National Hurricane Center Logo
National Hurricane Center

NOAA Aircraft Operations Center Logo
NOAA Aircraft Operations Center

Site Map

Staff Data Center Contact  Information

Research Divisions

Hurricane Research Division

Replies to Best Track Change Committee - March 2008

Replies by Landsea indented – March 2008

Minutes of the best-track change committee meeting, 20 November, 2007 
Members Jack Beven, Hugh Cobb, Richard Pasch, and chair (Colin McAdie) present.					
General comments: 

The committee met to discuss the responses from Landsea for the period 1915-1920, 
and as time allowed, 1924 and 1925.   Extensive but necessary discussion of the 
1916 Texas landfall precluded going beyond that year in the responses.   
See specific comments below. 
The committee previously requested an external review for U.S. landfalls 
storm #6 1915 (LA4 becoming LA3) and storm #4 (new #6) 1916 (ATX3 becoming ATX4) 
(i.e. changes up or down to cat 4-5 U.S. landfalls) from Brian Jarvinen.  
(minutes of 03 May, 2007).
This review was received and discussed.

The reply from Landsea first addressed general comments.    One issue not 
mentioned in the reply was the use of the phrase ‘a low of at most xxxx mb’  in the 
metadata.  The committee does not wish to create an unnecessary workload in revising 
all of the metadata, but suggests that going forward a phrase such as ‘central pressure 
near xxxx mb’ would be more clear to future users. 

	1. Unfortunately, such a phrase would not be accurate.  
	Depending on whom was doing the Historical Weather Map analysis, 
	the inner most closed isobar sometimes was meant as an approximation 
	of the central pressure and sometimes additional isolines were not 
	included for clarity of presentation.  Thus the phrase “a low of at 
	most xxxx mb” includes both of these possibilities.  

Concerning specification of the outermost closed isobar, the committee will seek to 
clarify what current operational practice is, and how this might be integrated into the 
quadrant system.   

Specific comments (as they relate to the reply): 

1915   #1.  Accepted.  Add ‘e’ to Jacksonville (first line).

	2.  Done.

1915  #2.   There are some remaining issues with the track.  Although it is stated in 
the reply that the track essentially goes over Dominica, in fact it goes over Guadaloupe. 
Reports from Dominica cited in the metadata indicate the peak of the event was ‘between 2 
and 5 o’clock on Wednesday morning.’  This argues for delaying the track by 6 hours, not 
12 hours.  As there are no observations available from Guadaloupe, should not Dominica be 
used to anchor the track? 
In the metadata for August 11, Santa Domingo is repeated.  Should this be ‘Santo Domingo, 
Dominican Republic?’ 
Also in the metadata for August 15,  should ‘Meridian’ be ‘Merida?’

	The track has now been adjusted to use Dominica observations to anchor the track.  
	The correct name of Merida is used. 

1915  #3.  OK 

1915 #4.   OK

1915 #6.  This change from category  4 at landfall to category 3 is accepted as final.  
External review by Brian Jarvinen concurs with this change.  
Addition of landfall effects for Mississippi (MS2) noted and accepted. 

1916 #0 through #3 OK

1916 #4 (new #6)  There are some remaining issues with this potential category 4 Texas  landfall.
The committee sought to clarify the related issues of storm size, track, intensity, and resulting 
storm surge.   Central to this discussion is the finding that Connor gives a storm surge value 
of 5.9 ft at Corpus Christi, while Ellis gives a value of 9.2 ft at Laguna Madre.   Laguna Madre 
extends for considerable distance along the coastline.  Previous runs of the storm surge model 
required a very large RMW to obtain 9.2 ft at Corpus Christi itself, which may not actually be 
required given this finding. 
As far as the RMW, it is relevant to note that none of the accounts in MWR describe a lull.  
This would support the assumption of a small RMW.  Also note that the system was described in 
MWR as ‘compact.’   
The pressure observations themselves also indicate a tight gradient, which would opt against a 
large RMW.  We also note that the landfall pressure of 932 mb is a reasonable assumption, but 
in fact may have been lower.  A lower bound of 925 mb would be appropriate for slosh model testing. 
Given the above, the committee will request addition storm surge runs using a wider set of assumptions.    
Please separate references to ‘Ellis and Connor’ in the metadata (last paragraph).

	As provided, the storm surge modeling runs have supported a Category 4, 
	which is what is reanalyzed here.  The references to Ellis and Connor have been 
	separated and clarified.

Minutes of the best-track change committee meeting, 30 November, 2007 
Members Jack Beven, Eric Blake, Richard Pasch, and chair (Colin McAdie) present.					
General comments: 

The committee met to resume discussion of the responses from Landsea for the period 1915-1920.  
The meeting started with discussion of 1916 (new  #7).   
The idea of a future project that would characterize systems as subtropical regardless of date 
was discussed.   There appear to be some cases where this determination could be made, but 
certainly not across the board.  The issue was not resolved. 
Specific comments (as they relate to the reply): 

1916  #5 (new #7).  OK.

1916  #6 (new #8).  OK.
1916  #7 (new #9).   Please clarify between adding positions at the beginning of the track and deleting 
at the end.   The original committee minutes concerned the possibility of adding two initial positions, 
but the response seems to address the dissipating positions.

	The first reply to the Committee was worded incorrectly.  It is agreed that the data cannot 
	adding additional initial positions on the 4th.

1916  #9 becoming #8 (new #10).   OK

1916 #10 becoming #9 (new #11).  OK   (Note error in original minutes – 995 mb should be 975 mb.)

1916 #11 (new #12) Removal proposed, now reinstated. 

1916 #12 becoming #10 (new #13)  OK

1916 #13 becoming #11 (new #14)  OK

1916 #14 becoming #12 (new #15)  Wording note on metadata, last paragraph.  Does the phrase
 “the storm had a central pressure of at least  982 mb”  mean that the pressure was near 982 mb 
and possibly lower?  Otherwise OK.

	The phrase was supposed to imply a pressure of 982 mb or higher.  This is now rewritten for clarity.

1916  additional systems,  OK.

1917 #1  OK.    (new)

1917 #2  OK.
1917 #3  OK.

1917 #4  OK.   Has the additional response from Perez actually been added to the metadata?  It does not 
seem to be there, at least in the version we have.

	Yes, the information from Perez about the calculation of the central pressure at landfall in Cuba is 
	included in the metadata writeup on the 25th.

1917 additional systems.   OK.

1918 #1  OK.

1918 #2  OK.

1918 #3  OK.

1918 #4  Please note the “CHECK!”  comment in the metadata on Sept. 6.  

	This has been corrected (needed the position from the Historical Weather Maps).

1918 #5  In the metadata, there is a blank instead of a zero for the original HURDAT position 
for 18Z 09/03.
An error in the original minutes is noted for this system.  The comments in question were 
on the 2nd, not the 3rd.  Minutes corrected. 

	This has been corrected.

1918 #6  This system is not plotted on the new chart.  Is this comment reversed? That is, 
didn’t the system turn westward, not northward?

	The chart is corrected to include this tropical cyclone.  The comment was accidentally 
	reversed.  The system did indeed turn westward.

(There does not appear to be any response on the additional systems for 1918.)

	For additional systems #1 and #2, no further comments are needed.  For additional 
	system #3, we always conduct an independent analysis of the observations and do not 
	rely upon the HWM for determination of closed systems and/or structural status.  For 
	additional system #4, it is unknown as to what “verifying velocity” refers to, as 1 hourly, 
	5 min, and 1 min winds were monitored systematically back in the early 20th century.

1919 #1.  OK.

1919 #2.  In the metadata for the 10th, it is stated that the Fred W. Weller reported 27.36  
inches in the vicinity of the Dry Tortugas on the 9th.   This appears to conflict with the lowest 
land-based observations reported for the 10th. 
The discussion concerning the potential downgrade to category 3 at landfall is ongoing. Note that 
the 950 mb ship report from the S.S. Kellogg is not plotted as a central pressure in Connor.  The 
question arose as to what it would take to create 16’ of storm surge at Corpus Christi.  (In answer 
to this question, the Javinen et al. reference was identified and distributed after the meeting.)  
A number of questions still surround this landfall.

	Indeed there is some somewhat contradictory information with the 
	dates/locations/pressures that have been recorded.

Minutes of the best-track change committee meeting, 29 January, 2008 
Members Lixion Avila, Jack Beven, Eric Blake, Hugh Cobb, Richard Pasch, and chair (Colin McAdie) present.					
General comments: 

The committee met to resume discussion of the responses from Landsea for the period 1915-1920.  The meeting 
became devoted to a discussion of 1919  #2, a landfalling major hurricane along the south Texas coast 
causing catastrophic damage to the Corpus Christi area, and causing many deaths.  
It was noted that the previous changes to landfalling category 4 hurricanes (1915, 1916) had now been 
resolved with a note from Brian Jarvinen as external reviewer agreeing to the changes for 1916. 

Specific comments (as they relate to the reply): 

1919  #2.  Although some uncertainty is the norm in historical cases, the committee wishes to stress 
that in this case the uncertainties are greater than normal.   What is well documented  is the catastrophic 
storm surge than devastated the area in the vicinity of Corpus Christi, including Port Aransas.  
The official death toll was 287.  

Meteorological data in the area of landfall is scarce.  In an earlier study, Jarvinen et al. used iterative 
runs of the storm surge model to show that a central pressure of 950 mb and a RMW of 40 statute miles did 
recreate the observed storm surge values rather closely, including 16 ft in Neuces Bay.  This study puts 
the center between Brownsville and Corpus Christi, with the RMW directly over the Corpus Christi area.  
A number of runs made as the system traversed the Gulf prior to landfall seem to support the contention 
that the system was weakening as it made landfall.   The only ship report available is from the Kellogg, 
which reported 950 mb well offshore, with an uncertain position of 27N, 95W.  Given the approximate position, 
it is not known where the ship was in relation to the center.  Given this, it is possible that the minimum 
central pressure was 10-15 mb lower at this time.   It is also noted that Connor takes the track just south 
of this approximate position.  

There was much discussion centering on whether to retain the category 4 designation or to accept the proposed 
change to category 3.   Given the uncertainty, and the catastrophic damage, a case could be made to retain the 
existing category 4.  However, the ensuing dilemma would be to ‘create’ a wind that would support this.   
Although not certain, it was suggested that the category 4 designation might have been based on the storm surge 
alone.  Current practice is to determine category based on wind alone.  

Landsea et al., using the new Brown et al pressure wind relationship with 950 mb, arrive at a corresponding 
wind of 100 kt.  Pending any further studies or data that would suggest otherwise, it was decided to provisionally 
accept this change.  Although possibly somewhat conservative, this will replace the 75 kt currently appearing 
in HURDAT, which may have been the result of an interpolation. 
It was noted during the discussion that a 170 mph gust was reported in Corpus Christi.  Further investigation by 
Jack Beven has shown that the anemometer was atop a six-story building in downtown Corpus Christi, in an environment 
of significant obstacle flow.   Under these circumstances, the gust cannot be taken as representative of the 1-min 
sustained wind near the surface. 

Because this is a change from category 4 to category 3 for a U.S. landfall,  the committee will ask Brian Jarvinen 
to review his previous work provide an outside opinion.   The committee will also inquire about the use of Hurricane 
Allen (1980) as an analog for this system.   Allen had a central pressure of 945 mb at the time of landfall. 

Final note: 
Some confusion with the numbering of remaining systems in 1919 has been resolved.  In the minutes of 1 June 2006, 
our comments under  ‘Additional systems’ contained the following: 

“5) The committee cannot discount the Tannehill interpretation,  and feels that this system may have been a hurricane 
ahead of the front.  Please note discussion in 1919 MWR pp. 660-661.  The 28.85 ship report cannot be assumed to be 
central, given a small system.”

Landsea et al. investigated, and this system has now become ‘new #3’ (a hurricane) for 1919.   The discussion in the 
Landsea reply appears under ‘1919 Additional system 5, now is new storm #3.’  This is the system heading northeast off 
the mid-Atlantic coast.
This has caused the ‘original’ new #3 to become new #4.  This is the tropical storm making landfall in Georgia.  Thus, 
the numbering in the reply is correct.  1919 now has a total of 5 systems, versus the old 3.       

Minutes of the best-track change committee meeting, 06 February, 2008
Members Lixion Avila, Jack Beven, Eric Blake, Hugh Cobb, Richard Pasch, and chair (Colin McAdie) present.					
General comments: 

The committee met to conclude discussion of the responses from Landsea for the period 1915-1920, 
and to discuss 1924 and 1925.

In the course of revising the Atlantic track book, a discrepancy was discovered between HURDAT 
and the existing track book map for 1938.   The track map for that year shows 1938 #4 making landfall 
as a hurricane (NY3, CT3, RI3, MA3) and then becoming extratropical.  HURDAT has the hurricane 
becoming extratropical at 18Z on the 21st, prior to landfall.  The committee agreed, pending 
any further reanalysis, to make HURDAT consistent with the track map by changing the 18Z position 
to tropical. 

	This change to the 1938 hurricane has been implemented as decided.  Note that a 
	detailed reanalysis for this hurricane (along with nine other major U.S. hurricanes for 
	the 20th Century) has been submitted for reanalysis evaluation.

Specific comments (as they relate to the reply): 

1919  new #3  Is there any possible source for Cry’s original notes that would indicate why this 
system was not originally included? 

	Cry’s book did not state why this system was excluded.  It is of note that the 1919 MWR, Mitchell’s 
	(1924) climatology, and Tannehill’s (1938) yearly summaries all did include this cyclone as a hurricane.

1919 #5  note spelling error “sparesness of data”

	Spelling error is corrected.

1920 #2  Accepted as revised.  

1920 Additional.  Note spelling error  “disturbanceds”

	Spelling error is corrected.

This concludes the discussion of the Landsea et al. reply for the 1915-1920 period. 

Return to Overview

[Horizontal Rule]

[OAR/DOC/NOAA Logos] Atlantic Oceanographic and Meteorological Laboratory Logo [United States Department of Commerce] [Atlantic Oceanographic and Meteorological Laboratory] Atlantic Oceanographic and Meteorological Laboratory Logo [National Oceanic and Atmospheric Administration] [Office of Oceanic and Atmospheric Research] Department of Commerce Logo National Oceanic and Atmospheric Administration Logo Ocean and Atmospheric Research Logo

  Disclaimer | Privacy