1152 MONTHLY WEATHER REVIEW VOLUME 126 Eastern North Paci®c Hurricane Season of 1995 EDWARD N. RAPPAPORT,LIXION A. AVILA,MILES B. LAWRENCE,MAX MAYFIELD, AND RICHARD J. PASCH National Hurricane Center, Tropical Prediction Center, NWS/NOAA, Miami, Florida (Manuscript received 3 September 1996, in ®nal form 28 January 1997) ABSTRACT The 1995 eastern North Paci®c hurricane season is reviewed. The activity comprised 11 tropical cyclones, consisting of seven hurricanes, three tropical storms, and one tropical depression. Hurricane Ismael caused a large loss of life in the southern Gulf of California. 1. Introduction gion. This pattern is also consistent with fewer than normal storms forming in the Paci®c and enhanced ac- The western hemisphere was a scene of stark contrasts tivity over the western Caribbean region (cf. Lawrence in tropical cyclone activity during 1995. More tropical et al. 1998). cyclones formed in the Atlantic hurricane basin than in In contrast to these atmospheric features, anomalies the eastern North Paci®c Ocean for the ®rst time in 26 of sea surface temperature (not shown) were small and years (cf. Lawrence et al. 1998). In fact, while the At- thought to be insigni®cant. In fact, when atmospheric lantic produced 19 tropical storms, its second largest conditions were conducive for development, the warm total during the past 125 years, the total of 10 tropical eastern Paci®c waters allowed three of the 10 tropical storms in the eastern North Paci®c Ocean ranks as the storms to strengthen to category 4 status on the Saf®r± second fewest in the 30-yr period of routine satellite Simpson hurricane scale (1-min wind speeds exceeding surveillance (1977 had 8 storms) and is 6 fewer than about 58 m s21). the average over that period. Of the 10 Paci®c storms, Most of the tropical cyclones followed the climato- 7 became hurricanes. There was also one tropical de- logically favored west-northwestward track from off- pression during May. It remained offshore. shore southwestern Mexico toward the relatively cool Several other measures were indicative of reduced waters west of the Baja California peninsula (Fig. 3). levels of activity in the eastern Paci®c. The ®rst storm However, three tropical cyclones adversely affected formed rather late, in mid-June. The last storm dissi- western Mexico. Flossie remained centered just offshore pated in late September making 1995 the ®rst year dur- but seven people lost their lives in coastal areas on its ing the satellite era without an October eastern Paci®c eastern fringe. Henriette caused damage where it crossed tropical cyclone. There were fewer than normal tropical southern Baja California but took no lives. A large loss cyclones in every month of the season. of life was reported in association with Ismael's north- Two persistent large-scale atmospheric anomalies ap- ward excursion through the southern Gulf of California. pear consistent with the decreased number of storms. Another unusual aspect of the 1995 season was the rel- Figure 1 shows anomalously strong easterly vertical atively short tracks of the cyclones that remained off- wind shear coinciding with the normal genesis area near shore. Only one system, Hurricane Barbara, crossed 128N, 1008W. This pattern was representative of both 1408W, entering the central Paci®c hurricane basin, and the average and many daily conditions and likely hin- it dissipated shortly thereafter. No other tropical cyclone dered tropical cyclone formation. A westerly wind reached 1308W and no other hurricane progressed to anomaly at low levels (Fig. 2) contributed to the shear 1208W. Table 1 provides additional information about pattern. It was associated with an eastward shift of the the tropical cyclones. zone of peak positive low-level convergence and vor- ticity from the climatological mean position over the eastern Paci®c toward the southwestern Caribbean re- 2. Tropical cyclone tracks The NOAA National Hurricane Center (NHC) trop- ical cyclone track database consists of a center position Corresponding author address: Dr. Edward N. Rappaport, Tropical and two measures of intensity (the maximum 1-min sus- Prediction Center, NOAA/NWS/NHC, 11691 SW 17th St., Miami, tained surface wind speed and the minimum sea level FL 33165-2149. pressure). The parameters are estimated at 6-h intervals. q 1998 American Meteorological Society Unauthenticated | Downloaded 09/23/21 01:35 PM UTC MAY 1998 RAPPAPORT ET AL. 1153 FIG. 1. Anomalies (m s21), from the 1975±95 mean, of the vertical shear of the horizontal wind (approximately 900 mb minus 200 mb) for (a) June and July and (b) August, September, and October 1995. They are based on a poststorm analysis of data con- Forecast unit), the NOAA Synoptic Analysis Branch ducted by the NHC.1 The primary sources for the anal- (SAB), and the Air Force Global Weather Central ysis are the National Oceanic and Atmospheric Admin- (AFGWC). These centers provided to the NHC real- istration (NOAA) Tropical Analysis and Forecast time estimates of position and intensity by applying the Branch (TAFB; formerly Tropical Satellite Analysis and Dvorak (1984) tropical cyclone analysis technique to imagery from the Geostationary Operational Environ- mental Satellites (GOES-7 and GOES-8) and polar- orbiting satellites. Observations from ships and land sta- 1 Track and ``®x'' data are contained in the Annual Hurricane Dis- tions supplemented these data. Figure 3 shows the 1995 kette Data Tabulation, available from the National Climatic Data Cen- ter, Federal Building, Asheville, NC 28801. Additional observations tropical storm and hurricane tracks and indicates where are contained in NHC Preliminary Reports found on the NHC Internet these systems were located at tropical depression, trop- Web site at http://www.nhc.noaa.gov. ical storm, and hurricane intensity. FIG. 2. Average low-level (approximately 900 mb) wind anomalies for (a) June and July and (b) August, September, and October 1995. Anomalies are 1995 minus 1975±95 averages in meters per second. ATOLL refers to analysis of the tropical oceanic lower layer. Unauthenticated | Downloaded 09/23/21 01:35 PM UTC 1154 MONTHLY WEATHER REVIEW VOLUME 126 . 3. Tropical storm and hurricane tracks for 1995. IG F Unauthenticated | Downloaded 09/23/21 01:35 PM UTC MAY 1998 RAPPAPORT ET AL. 1155 TABLE 1. Eastern North Paci®c hurricane season statistics for when it was forecast that the cyclone was going to move 1995. northwestward away from the mainland. The NHC has Maximum Minimum not received reports of casualties or damage related to 1-min sea level Adolph. wind pressure 21 Based upon Dvorak (1984) technique satellite inten- Number Name Class* Dates** (m s ) (mb) sity estimates, Adolph is estimated to have reached max- 1 Adolph H 15±21 Jun 59 948 imum 1-min winds of 59 m s21 and a minimum pressure 2 Barbara H 7±18 Jul 62 940 3 Cosme H 17±22 Jul 33 985 of 948 mb at 0600 UTC 18 June. The 3-h averages of 4 Dalila T 24 Jul±2 Aug 28 994 objective intensity estimates peaked near this time when 5 Erick T 1±8 Aug 28 994 satellite imagery indicated a small and distinct eye em- 6 Flossie H 7±14 Aug 36 978 bedded within very cold cloud tops. 7 Gil T 20±27 Aug 28 993 Adolph began weakening when the upper-level en- 8 Henriette H 1±8 Sep 44 970 9 Ismael H 12±15 Sep 36 983 vironment became less favorable and when the cyclone 10 Juliette H 16±26 Sept 67 930 moved over cooler water. On 19 June, the track of Adolph gradually turned toward the west. The cyclone * T: tropical storm, wind speed 17±32 m s21. H: hurricane, wind weakened to a tropical storm by 1200 UTC on this date speed 33 m s21 or higher. ** Dates begin at 0000 UTC and include tropical depression stage. and to a tropical depression by 1200 UTC on the fol- lowing day. Adolph dissipated on 21 June when the cyclone was centered about 550 km south-southwest of 3. NHC forecast accuracy the southernmost tip of Baja California. At this time The NHC began operational forecasting of eastern Adolph was characterized by a swirl of low clouds, no 21 North Paci®c tropical cyclones in 1988. Every6hthe deep convection, and maximum winds near 10 m s . NHC issues its ``of®cial'' tropical cyclone track and in- tensity forecasts for periods extending to 72 h. The fore- b. Hurricane Barbara, 7±18 July casts are evaluated using the track and intensity (5-kt resolution) dataset derived from NHC's poststorm anal- Hurricane Barbara's formation appears to have been ysis of all available information. Tables 2 and 3 show related to a weak tropical wave that crossed Dakar, Sen- the 1995 average of®cial track and intensity errors. They egal, as a large swirl of low clouds on 24 June. Based are comparable to the 1988±94 average errors. heavily on extrapolation, the wave moved westward over the Atlantic and then over South America with 4. Tropical storm and hurricane summaries little representation on satellite images or in rawinsonde data. The wave reached the eastern Paci®c on 5 July. a. Hurricane Adolph, 15±21 June There, convection developed and gradually became or- Hurricane Adolph formed from a tropical disturbance ganized. Satellite intensity estimates indicate that the that gradually became better organized off the southwest westward-moving system became a tropical depression coast of Mexico. The disturbance was possibly asso- at 1800 UTC 7 July about 925 km south of Manzanillo, ciated with a westward moving tropical wave, but a lack Mexico. The depression intensi®ed and became Tropical of suf®cient upper-air data and cloudiness makes it dif- Storm Barbara 12 h later.