Best Track Committee Re-Analysis Comments for 1932
[Replies to Comments in Boldface, Indented, and Bracketed – Chris Landsea – June 2011]
1932 Storm #1:
1. The committee has concerns about the origins of this system. The data on 5-6 May suggest the possibility of multiple centers in the Caribbean – one in the southwestern Caribbean and one farther to the northeast near 15N 75W. The latter is supported by a ship report of 1006 mb and northeast winds at 16N 76W at 2100 UTC 5 May. Please re-examine the genesis location of this system in light of that.
[Agreed that genesis location is near 14.7N 75W at 12 UTC on the 5th of May. Accordingly, position slightly changed on 6th.]
2. On 6 May, the ship with 1003 mb is almost four degrees from the center. Is the pressure correct? Is the center location correct? Please clarify this situation and adjust the proposed intensity if it appears that the 1003 mb report is incorrect.
[It appears that this ship’s pressure is unreliably low, in comparison with other ship observations nearby, though only this single ob from the ship is available for analysis. It is now mentioned in the metadata that this observation is likely unreliable.]
3. Are any significant observations from Santo Domingo available?
[No additional observations are available from Santo Domingo.]
4. The 35 kt ship report referenced in the 7 May metadata is also far (six degrees) from the center. Is it possible that this system had some subtropical characteristics?
[It is quite possible that the system had some subtropical characteristics, which is now mentioned in the metadata. The specific wind report may have also been at least partially forced by the synoptic-scale pressure gradient driven by the strong high pressure center near Bermuda.]
5. There is some confusion regarding the report from the ship Florida II on 10 May. The position given in the Monthly Weather Review and the metadata is near 27N 63W, which is far from the proposed track. However, this ship is given heavy weight in the intensity on that day, even though on the binder map there are speculations about whether it is a bad pressure or a bad location. Please clarify this. (Additional comments provided late: The 996 mb ship report at 0800 UTC 10 May is at least 300 n mi from the best track center position. This is considered as a “peripheral pressure” and was used to boost the winds from the original 40 kt to 55 kt. Even if this ship report were correct (which is dubious), it is too far away from the center to be used to estimate intensity. Suggest a gradual relaxation of the new best track wind speeds down to the original ones, say 50 kt at 0000 UTC 10 May, 45 kt at 0600 UTC 10 May, and 40 kt (the original speed) by 1200 UTC 10 May.)
[The time and position of this ship are incompatible with the numerous other observations available around 12Z on the 10th. Given the consistency of the ship’s winds and the pressures, it is assumed that these are correct and that the position of the ship is reported in error and that it was instead much closer to the tropical storm. This is now included in the metadata writeup.]
6. There is no map in the binder for 11 May. The committee would like to see this to confirm the details of the extratropical transition.
[This is now provided.]
1932 Storm #2:
1. The committee concurs with the proposed changes. One small question is whether a possible weak low west of Oklahoma City on the surface map for 15 August is the remains of the hurricane? Please look into this if the data allows.
[Agreed that the weak low southwest of Oklahoma City on the 15th is the remains of the hurricane and the HURDAT is extended to 18 UTC on this date.]
2. (Comments provided late: In the last paragraph of the metadata discussion, it is stated “Highest observed winds within two hours of synoptic time were ≥70 kt at 06Z…”. I believe that it was intended to state that winds of no more than 70 kt were observed, so replace “≥” with “≤”, or better yet to be even clearer, just state “Highest observed winds within two hours of synoptic time were no greater than 70 kt at 06Z…”.)
1932 Storm #3:
1. The HWM shows a southwest wind at San Juan, Puerto Rico on 24 August. In addition, the MWR rather specifically states that the center passed over the southwestern part of the island. These things suggest that the system had at least a strong vorticity maximum if not a closed circulation at that time. On the other hand, there is little evidence on the HWM of this being a depression on 25-26 August. Please try to locate other data from Puerto Rico to determine if the system was a tropical depression on 24 August, particularly one with a small core that might have slipped between the data points on the subsequent days.
[No other observations are currently available from Puerto Rico. It is noted that the Puerto Rico tropical storm and hurricane history (Perez 1971) did not list this system, despite the paper being a comprehensive documentation of even the weakest tropical cyclones to affect the island.]
2. The evidence for making this a hurricane over south Florida is a little thin. It is unclear from the description in the Key West OMR whether the stated winds from Fowey Rocks are sustained winds or gusts, or whether they were measure or estimated. Is there any other supporting data (e. g. unofficial pressures in the landfall area) that would support the upgrade? (Comments provided late: In the revised best track the time of landfall in extreme south Florida, 01Z 30 August, is earlier than that suggested by the original HURDAT by couple of hours. However the reports of northeasterly wind directions at Miami at 02Z and at Fowey Rocks lighthouse at 0245Z suggest that the original track is more realistic. Moreover, the upgrade to a Category 1 hurricane landfall in extreme south Florida is dubious and seems to be based entirely on the unofficial 77 kt wind report from the elevated Fowey Rocks site. Otherwise, the wind reports and impacts in Florida are not consistent with hurricane status.)
[It is likely that these winds from Fowey Rocks – which was a manned lighthouse at the time – were visual estimates based upon the sea surface. There are no other observations from south Dade County currently available. The track while over Florida has now been changed to be the same as that originally in HURDAT as suggested.]
3. On a related note, what local accounts of this system are available in south Florida? While this is not a memorable storm for the area, there could be information in local newspapers that could help determine if it was a hurricane or not.
[On-line archives for the Miami Herald are only available back to 1982 and there are none for the Miami News or other southeast Florida papers. Obtaining access to local newspapers in person is beyond the scope of this project.]
4. Is Bayou Batre in the 1 September metadata and the metadata summary supposed to be Bayou le Batre?
[Yes, so changed.]
5. Is there any data available from Pascagoula, Mississippi that would help calibrate the impacts in Mississippi? Should this storm also have an impact code of MS1?
[There are no other observations or impacts from Mississippi that are currently available. Agreed that this system should have an impact code of “MS1” for Mississippi, given the intensity at landfall, location, and translational speed of the hurricane.]
6. The HWM on 2 September suggest that cooler air was moving southward west of the center of the cyclone. Please double check the time of extratropical transition to see if it occurred earlier.
[It is agreed to move the extratropical transition up another 12 hours to 12 UTC on the 2nd.]
1932 Storm #4:
1. The committee has concerns about starting the system as a tropical storm on 30 August, especially since there is no evidence it was a significant system in the Virgin Islands or the Leeward Islands. It is noted that the new initial position at 18Z on 30 August is almost to 20N, which would be partly consistent with the NW wind at San Juan at 12Z. However, the other observations are more consistent with a vorticity maximum near 18.5N over the Leeward and Virgin Islands at that time. Please re-examine the genesis of this system.
[Agreed to begin the system as a tropical depression on 30 August farther to the south. Apparently, though with the 45 kt ship report at 20 UTC on the 31st, the cyclone began intensifying soon after genesis.]
2. The committee also has concerns regarding the peak intensity, especially if the system was actually a category 5 hurricane at Great Abaco. The pressure of 931 mb by itself does not support calling this category 5. What details are available regarding the pressure that is described as “reported pressure below 27.50 inches”? Was it a central pressure? This event was so extreme that it may be worthwhile to contact the Bahamas Meteorological Service for additional information.
[The Bahamas Meteorological Service has been contacted, but they have been unable to determine thus far if the reading was taken in the eye or eyewall of the hurricane. However, it does appear that the reading was from a barometer whose scale bottomed out at 27.50". Thus this is why it is noted as "below 27.50 inches". Because of this, the reading is likely not a central pressure measurement and the writeup is adjusted accordingly. However, there does not appear to be evidence to adjust the 140 kt that currently is in HURDAT for late on the 5th and on the 6th.]
3. Extratropical transition is shown as occurring at 18Z 8 September at an intensity of 85 kt. However, the data on 9-10 September suggests that ET may actually have occurred later. Additionally, while the 961 mb pressure suggests an intense system, the wind-pressure relationship might not apply as well for ET. Note that none of the wind observations seem to support a system of that strength, with the most significant obs in the 60-70 kt range. Please re-examine the timing and intensity of the ET, as well as the intensity during the rest of 8 September.
[There was a typographical error in the metadata writeup indicating that extratropical transition was around 18 UTC on the 8th. However, no change to the original timing of extratropical transition of 18 UTC on the 9th was actually meant. Thus 18 UTC on the 9th is retained for ET. With regards to the 961 mb pressure and its implications for intensity, given that the cyclone was very large, the intensity is revised downward to be 100 kt at 12Z on the 8th (down from 105 kt originally) and 90 kt at 18Z (down from 100 kt originally).]
4. (Comments received late:) The observations of tropical-storm-force winds from North Carolina northward through New Jersey, New York, and Nantucket while the center of the hurricane passed nearly 300 n mi offshore in the best track would indicate an extremely large storm, or perhaps the track should be closer to the coast. Could the track be shifted westward on 8 September and still be consistent with the available ship reports? Also, in the metadata daily discussion for Sept 8 the MWR Track of Centers of Cyclones showed a center near 35.5N, 70W not 25.5N, 70W.
[Agreed to adjust the track farther to the west on the 8th and 9th. Metadata corrected.]
1932 Storm #5 (new):
1. The committee concurs with the addition of this storm. (Additional late comment: Agree with the assessment that the data are consistent with the existence of a (previously undocumented) tropical storm.) Is there a chance that it had a subtropical structure during the early part of its life?
[Agreed that it is quite possible that it had a subtropical structure on the 4th and 5th of September. This is added into the metadata writeup.]
2. Can a map for 3 September be added to the binder?
[Yes, September 3rd is added into the binder and an additional daily summary included.]
1932 Storm #6:
1. Is there any data that would definitively rule out the cyclone being a tropical storm on 9-10 September?
[Data are sparse on the 9th and 10th of September for this system while in the southwestern Gulf of Mexico. At 12 UTC on the 9th, there is a ship about 75 nm from the estimated center with 20 kt SSE winds and 1008 mb pressure. This and other data are not inconsistent with a 35 kt tropical storm, thus no changes are made to the intensity on the 9th and 10th.]
2. On 11 September, there is a ship report of 1006 mb with winds NW 30 kt. While this is not direct evidence of the system being a tropical storm, it is significant enough that it should be mentioned in the metadata.
3. Is there any pressure data available on 15 September for the landfall in northwestern Florida? There is an Apalachicola OMR for August in the binder, but seemingly not one for September. How about other stations in the area?
[Lowest pressure recorded for the month of September in Apalachicola occurred on the 14th of September (local time – likely early 15th UTC) with 1002 mb. Highest winds observed in Apalachicola were 30 kt NE also likely early 15th UTC. (The OMRs are not available currently, but this summary information was obtained from the Florida Climatological Data report.) The only other stations with barometers and anemometers in the area were Jacksonville, Pensacola, Tampa, Savannah, Augusta, and Greenville. Of these, only Jacksonville had a low pressure and/or tropical storm force winds.]
4. There is a typo in the 16 September metadata – “26.5M”
5. (Comments provided late): In the last paragraph of the metadata, change “made landfall around 04Z on the 15th near 30.0N 83.9W in northwestern Florida” to “made landfall around 04Z on the 15th near 30.0N 83.9W in north Florida”. Taylor County is in the so-called Big Bend which is considered north Florida. Northwestern Florida implies the Florida Panhandle.
1932 Storm #7:
1. The committee concurs with the addition of this system once the caveats below are resolved.
2. The committee feels that the cyclone was likely subtropical on 16-17 September. Perhaps this is a good case to have a subtropical stage on the track map?
[It is strongly recommended to not indicate any subtropical storm in HURDAT until the advent of satellite imagery. Given that it is the distribution of deep convection that is part of what differentiates a tropical cyclone from a subtropical cyclone, attempting to specifically classify systems a subtropical cyclone before satellite imagery is problematic. 1968 marks the first year that a subtropical storm is currently in HURDAT. It is much preferred to continue the established practice of calling all pre-satellite systems that have some subtropical characteristics as a tropical cyclone, but to indicate in the writeup that “if satellite imagery were available, this system may have been considered a subtropical cyclone”.]
3. Please examine and make available the data for 15 September. This may help resolve the issues on the origin of the cyclone.
[The HWM is now provided and an additional entry for the 15th of September has been added into the daily summary. This does support the idea that the system formed from a decaying frontal boundary.]
4. Is the intensity jumping to 50 kt at 18Z 17 September correct? Right now, this makes for a choppy intensity curve.
[This was a typographic error and should have been 40 kt. Corrected.]
5. While not impossible, a system undergoing ET and continuing to move generally westward for several days is definitely unclimatological. Do the frontal boundaries observed on 20 September actually reach the center? How much of the observed temperature gradient may be due to the effects of the Gulf Stream rather than an atmospheric environment? (Comments received late: It is suggested that the metadata discussion also allow for the possibility that this system was a subtropical cyclone from the 20th through the 22nd given that the track was extremely atypical for a purely extratropical cyclone.)
[It is agreed that the system instead continued as a tropical cyclone until the 22nd, instead of becoming extratropical. It is noted in the metadata write that: “By the 20th, the cyclone’s wind field becomes asymmetrically tilted NW-SE and frontal boundaries appeared to have been developing in the system, though some of the baroclinicity may have been due to proximity to the Gulf Stream. However, during the 21st and 22nd a more symmetric structure and minimal baroclinicity were observed in the system as it continued moving westward at high latitudes.” With respect to the possibility that it was a subtropical cyclone on some of the dates: “It is possible that this system today – with the availability of satellite imagery – may have been considered a subtropical storm from the 16th and 17th and also from the 20th to the 22nd of September, instead of a tropical storm on those dates.”]
1932 Storm #8:
1. The data on 18 September appear to be problematic in supporting the tropical storm intensity in the original HURDAT. Is the data that day dense enough to justify a downgrade? Whatever the final decision on this is, please mention the uncertainty in the metadata. (Comments received late: The initial point in the original HURDAT shows a 35-kt tropical storm in the Bay of Campeche, and this is unchanged in the revised track. Could the genesis of this system, as a tropical depression, be indicated 6 or 12 hours earlier without violating the existing data?)
[Available ship and coastal observations – as is typical for the southwestern Gulf of Mexico during this era – are quite sparse on the 18th of September and it is ambiguous if the system began as a 35 kt tropical storm or weaker at 06 UTC. Given the prominent ship observations taken the next day indicating a high end tropical storm, no changes are made to the timing of when tropical storm intensity is reached. It is agreed to depict the genesis 6 hours earlier as a 30 kt tropical depression.]
2. The landfall position in Louisiana is shifted 60-90 n mi to the east. First, this is not a “minor” change (first paragraph of metadata summary). Second, this brings the track near New Orleans, which did not report gales as the storm went by. Third, southeastern Louisiana below New Orleans is not “unpopulated”. There would have been plenty of people there to notice the passage of the storm. Does the data justify this track change? What are the winds in the Morgan City OMR as the center goes by – northerly or southerly? (Hopefully there is a Morgan City OMR – we had one for the 1931 storm.) How about inland stations such as Vicksburg or Jackson? What local accounts are available? Please re-examine the landfall portion of the track and add more details to the metadata.
[“Minor” track changes are defined as those less than 120 nm (Landsea et al. 2008, 2011). It is agreed that the available data do not justify a 60-90 nm track change at landfall, though some adjustment toward the east before that time was needed because of the prominent ship observation late on the 19th. Standard practice in the past was to obtain OMRs for U.S. landfalling hurricanes, so these were not gotten previously. Unfortunately, the NCDC on-line site (EDADS) is down and may not be available again anytime soon. The revised track around landfall is now quite close to the original HURDAT in the absence of significant new observations to use in the reanalysis.]
3. Is there a possibility that the system dissipated prior to 12Z 21 September? Is it possible it underwent ET before dissipating?
[Dissipation after 18Z on the 21st is unchanged, as observations still (weakly) show a closed circulation in HWM at 12Z on that date. Despite the HWM indicating frontal boundaries extending through the system on the 20th, inspection of the observations instead shows the frontal boundary substantially northwest of the cyclone at that time. It is analyzed that the cyclone became extratropical around 00Z on the 22nd when the front reached the cyclone’s center. Previously there was no extratropical stage shown for this system.]
1932 Storm #9:
1. The committee has a concern about the proposed genesis time and location for this system on 25 September, given what appears to be anticyclonic flow over much of the Lesser Antilles area that day. This is admittedly very problematic, since the system was apparently a midget major hurricane the next day (see point 2). Is there any evidence of even a tropical wave east of the Antilles on 25 September or before that could be used to help refine the genesis timing and location?
[Unfortunately, as is typical there is essentially no observations east of the Lesser Antilles on the 25th or earlier that can assist in the positioning of the tropical wave that led to the genesis of this hurricane. Given the tiny size of the system on the 26th, it is quite possible that the estimated position on the 25th is reasonable.]
2. The intensity of this system on 26 September needs to be re-analyzed. In the binder, there is a letter with observations from the island of Saba, which include an uncertain minimum pressure of 710 mm of mercury (947 mb) and a bit more certain reading of 718 mm (957 mb) near 0830 local time. This is the likely source of the 948 mb central pressure and major hurricane status originally assigned for that day. While it is unknown if these observations have been corrected, the data shows that the pressure fell 44 mb in 90 minutes prior to the 957 mb reading, showing that the small inner core was already established at that time. The letter suggests that these were not central pressures, as there is no mention of a lull and the winds shifted from northwest to west to south. The letter also mentions an original publication for this data that should be tracked down if possible.
[The information from the letter from Saba to the U.S. Weather Bureau is now included into the reanalysis. The 948 mb central pressure originally in HURDAT – while uncertain given that the hurricane’s center did not go directly over the island – is reasonable and is retained, but moved to the 12 UTC slot. Closest approach to Saba is around 13 UTC on the 26th and the track is adjusted slightly to the west-southwest of that in the first reanalysis draft. A 948 mb central pressure suggests 113 kt from the Brown et al. south of 25N pressure-wind relationship. Given the very small size (44 mb pressure drop in 90 minutes before the recorded 957 mb), the intensity is boosted to 120 kt at 12 UTC on the 26th, up from 105 kt originally. The “Amigoe de Curacao” newspaper only has on-line archives back to 2000, but it is suspected that the Koninklijk Nederlands Meteorologisch Instituut provided all of the available observations to the U.S. Weather Bureau with this letter.]
3. If the system was rapidly intensifying at landfall in Puerto Rico, then the proposed 943 mb landfall pressure at 03Z on 27 September might not be representative of the pressure at the best track time three hours earlier. It is recommended that the 00Z pressure be removed. (Note: This issue may need to be re-visited in light of point 2.) (Comments received late: Agree wholeheartedly with bumping the maximum intensity upward. This hurricane clearly had an extremely small core as its center passed between the islands of St. Thomas and St. Croix, which are 40 n mi apart, and neither island appears to have experienced hurricane-force winds. This would imply a radius of hurricane force winds of less than 20 n mi and a radius of maximum winds (RMW) of perhaps less than 10 n mi. For the estimated central pressure of 943 mb (and it could have been lower given the 938 mb ship report), such a small RMW probably would yield an even greater maximum intensity than the revised 120 kt, probably 125 or 130 kt. Suggest revising the maximum intensity upward even a little higher. A good analogy to this storm might be Hurricane Charley of 2004, whose RMW was on the order of 10 n mi. Charley’s maximum winds at landfall in southwestern Florida was estimated from aircraft data to be 130 kt and its lowest central pressure was 941 mb.)
[If it is accepted that 948 mb may be a central pressure around 12Z on the 26th, then the rapid intensification likely ended late on that date, so retaining the 943 mb central pressure in the 00Z 27th slot as well as at landfall in Puerto Rico three hours later is reasonable. Agreed that the intensity should be boosted up to 125 kt.]
4. What is the basis for increasing the landfall intensity in the Dominican Republic from 70 to 105 kt? This is significantly above the one observed wind of 78 kt. Is this based on Decay Ships model data from the Puerto Rico landfall?
[Runs of the Kaplan-DeMaria inland wind decay model suggest 100 kt at 06Z on the 27th and 89 kt at oceanfall at 10Z on the 27th. Thus the intensity at 06Z is analyzed to be 100 kt and for 12Z until landfall in Dominican Republic are analyzed to be 90 kt.]
5. For the landfall in Belize, would 35 kt be more appropriate than 40 kt given the estimates of 37 kt from the wind-pressure relationship? Is there enough information to determine of the 1005 mb pressure in Belize City was the lowest observed pressure, or was inside the radius of maximum wind?
[Belize City had simultaneous 15 kt N winds and 1005 mb pressure. This would suggest about 1003 mb central pressure, as it is possible that the measurement was inside the RMW. If so, this central pressure would suggest 41 kt from the Brown et al. south of 25N pressure-wind relationship. Thus the original 40 kt appears to be reasonable to be retained in HURDAT.]
6. “…it is quite likely that it formed earlier with a weaker wind speed.” Since there is no evidence to support this, it is suggested that this either be removed, or change “quite likely” to “possible”.
[Changed to “possible” as recommended.]
7. What is the basis of the northwestward jump of the final best track point to the coast of the Bay of Campeche? Is it possible that the system dissipated before this occurred, or possibly moved into the Pacific? (Comments received late: Do the data really justify terminating this system 1 day earlier than in the original HURDAT? If this is agreed to, then the track map and caption for Storm Number 9 need to be adjusted to remove Oct 3. Also, what is the basis for the southward dip in the track shown on Oct 2?]
[This was my error with the track chart. As was discussed in the metadata, the system is judged to have dissipated 24 hours earlier than originally, with the dissipation point near the Guatemala/southeastern Mexico border. Observations from Mexico show no evidence of the original track with a second landfall in east central Mexico.]
1932 Storm #10:
1. The committee concurs with the addition of this system once the caveats below are resolved. (Comments received late: Surface temperature data seem to confirm that this system was non-frontal, so I cannot argue against its inclusion as a new tropical storm.)
2. There is a concern about the 70 degree temperatures near the center on 28 September, suggesting that the system might have been subtropical for this part of its life. Please examine this possibility.
[Agreed that the cyclone may have been subtropical on the 28th if satellite imagery were available, but then likely transitioned likely to fully tropical system on the 29th and 30th.]
3. It might be worthwhile to include a map for 27 September in the binder to illustrate how the previous history of the system is uncertain.
[Agreed. September 27th added to binder.]
1932 Storm #11:
1. What is the basis for discarding the 45 kt/999 mb observation on 7 October? What other data is close enough to this observation to conclusively prove it to be incorrect? (Comment received late: Wouldn’t it be reasonable to start the system as a 30-kt depression 6 to 12 hours earlier than the current HURDAT starting point over the northwestern Caribbean? Since the system was moving very slowly, this would only entail a little bit of backward extrapolation.)
[The observation appears to be inconsistent with the other measurements that show an elongated west-east trough, all of which show winds 10-15 kt and pressures 1008-1010 mb. Additionally, the ship only reported once in the several days of this system’s lifetime, which is suspicious (most ships report once daily or four times a day) and also does not allow for inspection of a time series for the ship. This does not conclusively prove it to be incorrect, but it is likely to be incorrect. Agreed to have genesis begin at 00Z on the 7th of October in the western Caribbean, twelve hours earlier than shown in HURDAT originally. ]
2. Please better document the low pressure bias of the ship US097284 on 9 September and show how the figure of the 10 mb bias was arrived at. The committee feels that this documentation is important, since if this data is taken at face value it would strongly suggest the system was a hurricane. In addition, the raw data says this ship reported 983 mb where the text says 982 mb. Please clarify this.
[There are two main pieces of evidence that the ship had a low bias in its pressure measurements. First, the highest wind reported from the ship from its hourly observations was 45 kt, despite several pressure readings below 995 mb, the lowest of which (at the time of the 45 kt measurement) was 987 mb. Moreover, comparison of these observations with nearby ships – especially ship “Car.” in the HWM that had nearly the same wind speed and same direction at a location about 20 nm apart - suggests that these pressures were likely low biased by about 8 mb. The raw data provided had both a 982 mb pressure at 20 UTC and a 983 mb pressure at 21 UTC from ship US097284.]
3. The committee has some issues the evolution of this system after landfall in Belize. One possibility that the cyclone dissipated over Central America, and that the system that tracked across the Gulf of Mexico was a separate and baroclinic low. Another is that the cyclone continued as currently depicted, but with extratropical transition delayed until 16 October, possibly after landfall. A third is that the low trying to develop in the Pacific on 12 October became the primary focus of development and absorbed the original Caribbean cyclone. Please re-examine this part of the proposed life cycle in as much detail as the data will allow.
[It is agreed that the evolution of the system is quite ambiguous, especially from the 11th to the 14th, because of the sparse nature of observations over Central America and the Gulf of Mexico. These various additional scenarios are plausible and are also mentioned in the writeup of the system. It is, however, relatively clear that a cyclone (whether or not if it is the same continuous system) was extratropical by late on the 15th. Extratropical transition is now suggested to have occurred around 18Z on the 15th, 12 hours after than indicated in the first reanalysis draft.]
4. It is noted that in the metadata summary states “available data do suggest that the tropical cyclone had entered the Gulf of Mexico”. Could you please provide more details on just which observations show this, as it is not obvious from the HWM or the data in the binder.
[The statement is revised to state: “By the 13th, unfortunately, the Mexican observations were quite incomplete, though available data are not incompatible with the tropical cyclone entering the Gulf of Mexico, as suggested originally by HURDAT.”
5. Give the low environmental pressures around the cyclone on 14 October, would a 40 kt intensity be preferable to 45 kt?
1932 Storm# 12:
1. What is the basis for the track change on 8-9 October? Please document this in the metadata even if the ship reports are not significant in terms of winds or pressures. (Comments received late: While I agree that the surface data do not support a closed circulation as far back as 12Z 7 October, this storm could be initiated as a 30-kt depression near 23-24N 57W at 00Z 8 October.
[The initial position is repositioned toward the northwest based upon a ship observation near the cyclone, with a major change introduced at 06Z (which is the only major track change for this system). Minor track alterations are introduced for the remainder of the cyclone’s lifetime. This ship is now included in the daily summary. Agreed to adjust the genesis to 00Z on the 8th.]
2. In the 10 October daily metadata, the Bermuda winds are 25 kt, while in the metadata summary the Bermuda winds for this date are shown as 20 kt. Please clarify this.
[20 kt is accurate. Corrected in the daily summary.]
1932 Storm #13:
1. The committee concurs with the addition of this system once the caveats below are resolved.
2. The committee would like to see data from 21 October to help determine whether the cyclone dissipated or merged with a front. The abrupt ending as a 35 kt system on 20 October is a little disconcerting.
[HWM and COADS indicates a trough of low pressure in the vicinity of 27N, 42W to 29N, 32W. The system is dissipated after 00Z on the 21st though observations are sparse on this date, so it is possible that the system continued slightly longer than indicated.]
3. (Comments received late: Agree with inclusion of this system as a new (strong) tropical storm. However, why does the MWR account for 17 October state that it “…moved slowly northeastward past the Azores during the four days that followed,…” but the proposed track never reaches the Azores?)
[Apparently, the MWR account is incorrect. This discrepancy is now mentioned in the summary paragraph.]
1932 Storm #14:
1. The committee concurs with the reduction in the intensity as the cyclone is passing through the Lesser Antilles. Is it possible that the system was even weaker at that time and was a depression instead of a storm?
[Agreed that the system likely was a tropical depression while crossing the Lesser Antilles. Winds reduced accordingly from the 30th until early on the 1st.]
2. The lowest observed pressure in the Lesser Antilles was 1008 mb at Port Castries, St. Lucia, and the maximum 24 hour pressure falls in the area were south of Guadeloupe, which is where the current track and the Monthly Weather Review suggest the center was. Based on this, could this and the adjacent portions of the track be adjusted southward?
[Agreed, track adjusted southward.]
3. There is a question about the 1002 mb observation near 14.5N 71.5W on 1 November. Is it in the right place, given that it is so far from the track?
[Given that the ship reported 1002-1003 mb for four observations during the 1st at a location about 300 nm west of the cyclone, either the position of the ship is erroneous or the pressure values are biased low. It is concluded that the latter is the case and these values are now downplayed in the metadata writeup.]
4. Does the data allow for the kink in the track on 2 November to be smoothed out?
[Agreed, kink is smoothed.]
5. Is there any basis, other than the Monthly Weather Review account, for making the system a hurricane on 2-3 November? The proposed intensities seem to be well above that supported by the data. Can the metadata include more information on where the observations were in relation to the center and how conclusive the observations are about the intensity? (Comments received late: There does not appear to be any inner-core observations to support the reductions in intensity on 1-2 November.)
[The comments provided by the committee are contradictory. Given that there are no inner core measurements from the 1st until the 5th, the intensity is begun at 00Z on the 1st as a 40 kt tropical storm (based upon evidence that the system was still a tropical depression around 12Z on the 31st crossing the Lesser Antilles) and then ramping up 5 kt per each six hours until the original intensity in HURDAT is matched at 00Z on the 3rd at 80 kt. This delays the onset of hurricane intensity by 18 hours, from 12Z on the 1st to 06Z on the 2nd.]
6. 6 November metadata: “70 kt NW with pressure of 915 mb”. Is 70 kt the way it was described in Tannehill? Does the same thing apply for a similar description in the 7 November metadata?
[The winds in the Tannehill are described either as “force 12” or “hurricane force”. Force 12 in the Beaufort Scale begins at 64 kt and is open ended. Typically, these are listed as being 70 kt. For clarity, these observations are appended with “(force 12)” to distinguish from an anemometer measurement of exactly 70 kt.]
7. The committee concurs with the upgrade to category 5 status.
8. In the 9 November metadata, there is a reference to a 940 mb pressure at Nuevitas from Perez, and a pressure of 977 mb at Nuevitas from the Monthly Weather Review. This is a bit confusing and needs clarification. Which of these values is the actual minimum pressure? (Comments received late: In the second paragraph of the metadata discussion where it is stated “Given the rather large size (climatology for this latitude and central pressure would be 12 nm)”, I presume this is in reference to the eye size. If so, please state. The major upward adjustments in intensity for 5-9 November seem reasonable based on the reports from the vessel Phemius and the observations from Cuba.)
[The 977 mb observed in Nuevitas mentioned in Monthly Weather Review was what was reported from Cuba to Miami before the communication lines were lost – see fortuitous newspaper article from the Nassau Guardian. 940 mb was the observed minimum pressure at the station provided by Perez et al. Yes, the size in this regards refers to the RMW.
In a related note, Perez prefers a 137 kt (Category 5) impact for Cuba because of the central pressure, storm surge, and impact. However, given the very large RMW and low environmental pressures, it is preferred to analyze the intensity below the pressure-wind relationships and keep 130 kt. It would appear that Hurricane Katrina’s impact in the U.S. Gulf Coast would be a reasonable analogue to the Huracan de Santa Cruz del Sur. Perez’ recent letter is provided below:
I could see and review the draft reanalysis of the 1932 hurricane season.
The main attention to
the storm Nr. 14, the Santa Cruz del Sur hurricane, especially to :
“... The Perez et al. analysis obtained central pressure estimates at
landfall in Cuba of 918 mb and 919 mb from the Schloemer equation from the
track and these two pressure readings, respectively. The 918 mb central
pressure, revised track, and a radius of maximum wind of 30-35 nm provided a
close match from a storm surge model to the observed 6.8 m storm surge in
southern Cuba. This pressure suggested maximum winds of 140 kt from the
Brown et al. south of 25N pressure-wind relationship (and 134 kt from the
weakening subset). Given the rather large size (climatology for this
latitude and central pressure would be 12 nm - Vickery et al.), low
environmental pressures (1008 mb outer closed isobar) and near average - 13
kt - translational velocity, an intensity of 130 kt is analyzed for the
landfall in Cuba. This is Category 4 on the Saffir-Simpson Hurricane Wind
Scale and is just slightly less than the 137 kt estimated by Perez et al....”
I understand your thinking, but taking in account what storm search
occurred and damages I prefer the 137 kt to the 9th at 12z,
135kt to the hurdat. Of course, a category 5 hurricane landfalling on Cuban
Ramon Perez – 31 May, 2011”
9. How far are Cayman Brac, Camaguey, and Nuevitas from the proposed track?
[None of the observations have a time, so these distances are closest approach: Cayman Brac is ~10 nm from the track at 06Z November 9th, Camaguey is ~20 nm at 17Z, and Nuevitas is ~30 nm at 19Z.]
10. What is the basis of raising the intensity to 85 kt on 12 November? While this does not appear unreasonable given that Bermuda was on the weak side of the storm at a large distance, it requires a better explanation in the metadata summary.
[While on the weak side of the cyclone, Bermuda recorded peak winds of 76 kt (“forenoon”) and minimum pressure of 972 mb at 12Z, while a ship just south of Bermuda observed 978 mb with simultaneous 45 kt W winds at 12Z. 972 mb suggests winds of at least 82 kt from the north of 25N pressure-wind relationship. Intensity of 85 kt is analyzed for 12Z (up from 75 kt originally) on the 12th, based upon the pressure-wind relationship.]
11. The metadata summary states, “No inner core observations were available on the 3rd and the 4th and no intensity changes are introduced until late on the 14th.” Did you mean on the 4th of November?
12. In the metadata summary, replace “Neuvitas” with “Nuevitas”.
[Note that additional observations obtained in the Nassau Guardian from the Bahamian Weather Service has provided some confirmation of the major hurricane impact in that country as well as more specifics on the landfall location and timing.]
1932 Storm #15:
1. The committee concurs with the proposed changes. (Comments received late: Ship reports of 60-kt winds are listed at 06Z, 12Z, and 18Z 6 November and 00Z, 06Z, and 12Z 7 November – all located at 29.5N 50.5W. Is this a stationary platform or are these reports erroneous?)
[These reports came from COADS and apparently are from two separate ships - #6042156 on the 6th and #6042222 on the 7th. It is noted that the former ship did report from a different position at 00Z on the 6th (28.5N 50.5W). The data obtained are consistent with nearby ship observations and appear to be reliable.]
1932 Additional Notes:
1. The committee notes during the May system Mobile and Pensacola reported 35 kt southeasterly winds on 19-20 May. Please re-check the data on these days to ensure the system lacked tropical characteristics during that period.
[The cyclone was re-examined and it was determined that it remained extratropical throughout its lifetime.]