1956 Atlantic Hurricane Database Reanalysis – Sandy Delgado and Chris Landsea Red indicates wind changes of 15 kt or greater Yellow indicates a deletion Green indicates a new entry Blue indicates lat/lon changes greater than 1º “Minor” intensity changes are less than 20 kt “Minor” position changes are less than 2 degrees Unnamed Tropical Storm 1 [June 12-15, 1956] – AL011956 39285 06/12/1956 M= 4 1 SNBR= 858 NOT NAMED XING=1 SSS=0 39290 06/12*220 915 25 0*225 913 30 0*231 912 30 1009*240 910 35 0* 39290 06/12*200 915 25 0*203 915 25 0*208 915 30 0*216 915 35 0* *** *** *** ** *** *** **** *** *** 39295 06/13*253 907 40 0*264 907 50 0*275 909 50 1004*290 908 45 0* 39295 06/13*230 915 40 0*251 913 45 0*275 909 50 1004*294 906 50 0* *** *** *** *** ** *** *** ** 39300 06/14*306 905 40 0*322 910 35 0*338 917 25 1006*347 928 25 0* 39300 06/14*310 906 35 1001*324 910 30 0*338 917 25 1006*345 928 25 0* *** *** ** **** *** ** *** 39305 06/15*349 933 25 0*352 938 20 0* 0 0 0 0* 0 0 0 0* 39310 TS U.S. Tropical Storm Landfall ------------------------------------- 06/13 17Z 29.1N 90.7W 50 kt LA Major changes to the track and minor changes to the intensity shown in McAdie et al. (2009). Evidence for these alterations comes from the NHC microfilm maps, the Historical Weather Maps series, the COADS ship database, Monthly Weather Review, the Local Climatological Data, Surface Weather Observations, Connor (1956), Navy reconnaissance book (ATSR), and Mexican synoptic maps. June 11: HWM, HURDAT and MWR does not analyze an organized system at 12Z. Microfilm shows a low pressure over eastern Mexico and a tropical wave/trough along 92W at 12Z. No gales or low pressures. June 12: HWM does not analyze an organized system over the Gulf of Mexico at 12Z. HURDAT lists this as a 30 knot tropical depression at 23.1N, 91.2W at 12Z. Microfilm analyzes a low pressure of at most 1011 mb centered near 20.2N, 92.5W at 12Z. MWR shows a low pressure of 1009 mb located near 20.3N, 91.8W at 12Z. No gales or low pressures. “This was the second tropical storm to occur in June in 10 years. On June 9, a fracture occurred in the polar trough lying just off the Atlantic coast, and the southern section began moving westward across Florida into the Gulf of Mexico while the northern portion continued eastward over the western Atlantic. The westward moving southern section apparently induced an easterly wave which moved across the extreme western Caribbean, western Cuba, southern Florida, and the Yucatan Peninsula, and on the 12th formed a depression in the Bay of Campeche under the mid-tropospheric trough.” (MWR) June 13: HWM shows a closed low pressure of at most 1010 mb centered near 28.3N, 91.5W at 12Z. HURDAT lists this as a 50 knot tropical storm at 27.5N, 90.9W at 12Z. Microfilm analyzes a closed low pressure of at most 1005 mb centered near 28.2N, 90.9W at 12Z. MWR shows a low pressure of 1004 mb located near 27.8N, 91.2W at 12Z. Ship highlights: 40 kt SE and 1013 mb near 24.0N, 87.4W at 06Z (micro). 35 kt SE and 1008 mb near 28.2N, 90.1W at 12Z (micro). 40 kt SSE and 1008 mb near 28.7N, 89.3W at 18Z (COADS). Land highlights: 40 kt SE and 1011 mb at SW Pass Lighthouse, LA at 12Z (micro). 48 kt E with 1011 mb at Grand Isle, LA at 1315Z (MWR/SWO). 41 kt SSE with 1008 mb at 15Z at Burrwood, LA (SWO). 1004 mb with 19 kt SSW winds at New Orleans-Airport Station at 2025Z (MWR/SWO). 1004 mb with 18 kt SSE winds at New Orleans-Naval Air Station at 2200Z (SWO). 40 kt at Golden Meadow, LA (no time given) (CONNOR). Aircraft highlights: 40 kt maximum wind and 1009 mb minimum pressure and “no circulation” (ATSR); 35 kt SE with 1012 mb at 19Z at 27.2N 88.8W (micro); 35 kt SSE with 1013 mb at 27.5N 87.3W at 1830Z (micro). “The disturbance moved northward, acquiring tropical storm intensity and the center crossed the Louisiana coast a short distance west of Grand Isle during the late afternoon of the 13th. According to the report from the hurricane forecast center at New Orleans, “The storm had both tropical and extratropical characteristics. Rainfall was tropical in nature but never formed in bands characteristics of tropical storm and there was never any definite center or eye. The temperature aloft over the surface Low remained as cold as or colder than the surrounding air.” The situation in the high troposphere was also markedly different from that usually observed during hurricane formation.” “The highest wind reported ashore was 55 mph from the east at Grand Isle, at 0715 CST on the 13th. A boat 5 miles south of Pilottown, La, reported gusts to 60 mph from the south-southeast. The lowest observed pressure was 29.66 inches at Moissant Airport, New Orleans, and at McComb, Miss. The highest measured tide was 4.7 feet above mean sea level at Biloxi, Miss… Tides generally ranged from 1 to 4 feet above normal along the Louisiana and Mississippi coasts. The Freeport Sulphur Co. suffered some damage to their sulphur mines near the coast south of Houma, La, where the tide was 4.5 feet above mean sea level. Minor damage to the beaches, small boats, and piers occurred along the Mississippi coast in places where tides were said to have reached as much as 5 feet above mean sea level. The total damage from this storm is estimated at $50,000.” (MWR) June 14: HWM shows a closed low pressure of at most 1010 mb centered near 34.0N, 92.5W at 12Z. HURDAT lists this as a 25 knot tropical depression at 33.8N, 91.7W at 12Z. Microfilm analyzes a closed low pressure of at most 1008 mb centered near 34.0N, 92.0W at 12Z. MWR shows a low pressure of 1006 mb located near 33.5N, 91.5W at 12Z. Land highlights: 1004 mb with 15 kt NE at McComb, MS at 0128Z (SWO/CONNOR). 5 kt N and 1005 mb at Liberty, MS at 0Z (micro). “At 250 mb, at 0300 GMT on the 12th, an intense cyclonic circulation was centered southwest of Fort Worth and at 0300 GMT on the 14th this center had moved almost over the tropical storm in Louisiana.” (MWR) June 15: HWM shows a low pressure system over SW Wyoming with a cold front to the south and a warm front to the east stretching over the north of the US. The tropical cyclone appears to have dissipated. HURDAT lists this as a 20 kt tropical depression at 35.2N, 93.8W at 06Z (last position). Microfilm does not analyze an organized system at 12Z. No gales or low pressures. This system developed in the Bay of Campeche during the second week of June as a tropical wave moved into the region. Genesis of this tropical storm is kept at 00Z on the 12th of June, but ship and land stations data on this day indicate that the center was located about 120 nm south than originally shown in HURDAT, a major change. Only minor changes to the track were subsequently introduced on the 13th, and 14th, with no alterations on the 15th. The cyclone is initialized as a 25 kt tropical depression, as originally shown in HURDAT. The depression moved northward, initially slow but gaining forward speed later in the day. A central pressure of 1009 mb was in original HURDAT at 12Z and appears to be an estimate, not an actual measurement. A ship reported 20 kt E and 1009 mb, therefore, the 1009 mb at 12Z has been removed. Intensification to a tropical storm occurred at 18Z on the 12th in agreement with the original HURDAT. The first gales were observed early on the 13th as various ships reported 35-40 kt about 150-300 nm away from the center. At this time the system was moving at about 22 kt to the north with an elongated N-S structure and most of the rainbands and winds concentrated on the eastern quadrant. The structure, as mentioned by the Monthly Weather Review summary, exhibited subtropical characteristics and it is possible that during this time this system was a subtropical cyclone. Note, however, that formally designating systems as “subtropical” is not feasible until the advent of satellite imagery to assess the convective distribution. Nonetheless, intensification continued and by 12Z on the 13th it had reached a peak intensity of 50 kt as originally shown in HURDAT. A central pressure of 1004 mb was on the original HURDAT at 12Z on the 13th and appears to be an estimate, but it looks to be reasonable and is retained. At this time, the cyclone became more symmetric and the circulation became more concentrated although the winds remained stronger on the eastern quadrant. Another reason for the winds to be stronger on the eastern semi-circle was the presence of an intense high pressure system over the Ohio Valley causing a strong pressure gradient on that side of the storm. Landfall occurred around 17Z on the 13th on southeast Louisiana near 29.1N, 90.7W with maximum winds of 50 kt, no changes from original HURDAT.