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

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

Colin J Mcadie wrote on July 2nd:

Committee members:
We have had a couple of weeks to look over Chris's response to our comments 
of 29 April 2003 (these are our 'second round' comments on 1851-1910).   
Principal issues were changes made based on lack of data, and the 
consolidation of 1891 #7 #8 #9, which we rejected.  I believe that Chris 
has complied with the lack of data issue, all of our other concerns, and has 
left the three systems as they appear in Neumann et al.  Given this, I would
like to give Chris our approval and to incorporate the revisions
into our best-track file.  Please let me know by the end of the day tomorrow
(Thursday [July 3rd]) if you agree.



Colin J. Mcadie wrote on July 7th:

Almost a green light - on our final review, Jack provided a couple of 
comments for your clarification.

Jack Beven's comments:
I did find a few points that need clarifying...

1879, storm #2: Chris assigns this storm a 100 kt intensity based on
a 971 mb central pressure and a 16 n mi RMW.  This is quite an increase
over the 85 kt from Chris' own subtropical wind pressure relationship, and
major hurricanes with central pressures of 971 mb in North Carolina (or
elsewhere for that matter) are not exactly common. I recommend taking
another look at the RMW to see if it justifies that much of an increase in

   < This is a fascinating case.  While the 100 kt estimate for maximum
     1 min surface winds to impact North Carolina appears at first glance
     to be too high to be supported by a 971 mb central pressure, a review
     of the available evidence does support a major hurricane at landfall.
     As stated in the metadata, 971 mb suggests winds of 85 kt from the
     subtropical wind-pressure relationship.  Ho (1989) suggested a rather
     small RMW of 16 nmi based upon the peak observed winds in Cape Lookout
     and the eye passing just over/slightly west of Moorehead City.  This
     estimate appears reasonable, but certainly could be plus/minus 5 nmi.
     However, the measured winds in Cape Lookout themselves are probably
     the best evidence for maintaining major hurricane status.  The winds
     there measured by the Signal Corp officer reached 120 kt maximum wind
     (typically measured as a 5 min wind in that era) when the anemometer
     blew away.  The observer estimated that the winds increased and 
     reached about 145 kt at their peak.  It turns out that the 
     measurement of 120 kt is the highest ever observed by the old 4 cup
     Robinson anemometer in a hurricane during the 19th Century (Kadel
     1926).  These older anemometers had a rather nasty high bias, however,
     and the 120 kt value likely represented a true value of 91 kt 
     (Fergusson and Covert 1924).  Converting this 5 min wind to today's
     1 min standard (Powell et al. 1996) gives 97 kt.  If one were to 
     trust the observer's estimate of a highest wind of 145 kt, this would
     also convert to about 115 kt peak 1 min wind.  However, winds 
     estimated visually are notoriously unreliable so little stock is
     placed in this value (which would even place this hurricane into the
     Category 4 status), except to say that the winds peaked higher than
     the 97 kt when the anemometer was destroyed.  Another consideration
     for boosting the winds above the wind-pressure relationship is the
     forward speed of the hurricane.  The hurricane was in the process of
     accelerating northward as it recurved and had a translational 
     velocity of about 25 kt, which is above the climatological value of
     about 18 kt for that location (Neumann 1993).  A faster than usual
     system would have enhanced winds on the right semi-circle of the storm.
     Finally, corroborating evidence to retain this as a major hurricane at 
     landfall is found in the descriptions in Partagas and Diaz (1995b), 
     Barnes (1998b), and Ho (1989) of a quite destructive hurricane from 
     both wind and surge.  Dunn and Miller (1960) also termed it an 
     "extreme" hurricane.  The bottom line is that the available evidence 
     is that it was a small, swiftly moving hurricane with maximum 1 min 
     winds at landfall in North Carolina of about 100 kt.  (These points
     are added into the metadata file as well.) >

1879, Storm #3: Two questions concerning the 988 mb reading
in Shreveport, Louisiana:

1) Is this a sea-level pressure or a station pressure?

2) Even if this is a sea-level pressure, Shreveport is 200 n mi
inland and I'm not sure any tropical cyclone wind-pressure relationship
holds that far away from the coast. Is there any wind data to support
a 60 kt intensity? If not, I would suggest the 60 kt winds at 12Z
on 23 August be reduced to a more reasonable value.

     < Pressures in the 1879 Monthly Weather Review were reported as
     anomalies from station averages, rather than standardizing to sea
     level.  Their anomaly was a negative 0.73" on the morning of August 
     23rd, which translates to about a sea level pressure of 988 mb.  It 
     is agreed, however, that a maximum 1 min surface wind of 60 kt is too 
     high for an inland system, given a Gulf of Mexico wind-pressure
     relationship suggesting 65 kt.  Winds are reduced to 50 kt (increments 
     of 10 kt are utilized from 1851 through 1885) to correspond to this 
     pressure observation. > 

1898, Storms #7 and #8: While the series of events that Chris
has gone with matches what was originally stated in the Monthly
Weather Review, the meteorology of this situation troubles me.
Storm #8 is moving northeastward on the northwest side of storm
#7 - a developing major hurricane - and by 28 September the
two systems are only 400-500 n mi apart. Would a northeastward
motion for storm #8 be reasonable under those conditions? Chris
needs to give this situation a closer look.

   < Agreed that these storms need further analysis.  We will 
     investigate these two storms with the assistance of the COADS
     database, since the Historical Weather Map series did not begin
     until 1899.  This will be accomplished in the next round of
     revisions. >

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