GARY PADGETT'S MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY FEBRUARY, 2004 (For general comments about the nature of these summaries, as well as information on how to download the tabular cyclone track files, see the Author's Note at the end of this summary.) ************************************************************************* FEBRUARY HIGHLIGHTS --> First Northwest Pacific tropical storm of the year develops --> Severe tropical cyclone strikes northwestern Australia --> South Pacific cyclone damages Vanuatu ************************************************************************* ***** Feature of the Month for February ***** TROPICAL CYCLONE CLIMATOLOGICAL DATA for the AUSTRALIAN REGION A. Introduction --------------- This month's feature is the third of three highlighting tropical cyclone climatological data for the Southern Hemisphere. The source for the data was a set of tropical cyclone tracks sent to me by Mr. Charles Neumann. These had been prepared in association with a hurricane risk analysis (HURISK) study he was performing for the U. S. Navy. Earlier studies had been accomplished for the Atlantic and North Pacific basins. The tracks and intensities were based upon available data sets for the various Southern Hemisphere basins from the regional warning centers, and from 1980 onward, JTWC's Best Track files were utilized as an additional source of data. The data set begins with the 1960-61 Southern Hemisphere cyclone season and extends through 2001-2002, and I have included the entire period. While the annual number of intense tropical cyclones (MSW < 100 kts) increases somewhat around 1970, the numbers of tropical storms and hurricanes during the pre-1970 period are not significantly different than for years following the advent of meteorological satellites. No doubt in pre-satellite years many cyclones were not detected, especially in the vast island-free South Indian Ocean. But in some areas, such as northern Australia, where most storms form near land and affect the coastline, and also in the island-rich South Pacific, it is likely that most significant tropical cyclones were at least detected (even if not tracked accurately) before operational satellite coverage became complete in the late 1960s. B. Definition of Parameters --------------------------- The following definitions apply: NS - a tropical cyclone with a peak 1-min avg MSW >= 34 kts H - a tropical cyclone with a peak 1-min avg MSW >= 64 kts IH - a tropical cyclone with a peak 1-min avg MSW >= 96 kts NSD - four 6-hour periods in which a NS is operating HD - four 6-hour periods in which a H is operating IHD - four 6-hour periods in which an IH is operating NTC - (((Total NS/Avg NS) + (Total H/Avg H) + (Total IH/Avg H) + (Total NSD/Avg NSD) + (Total HD/Avg HD) + (Total IHD/Avg IHD))/6) x 100% I have included another seasonal measure of the overall tropical cyclone level of activity which I developed--the Tropical Cyclone Index (TCI). It is a summation of the MSW for each 6-hourly data point, divided by 100 (kts) with the resultant quotient then squared. Thus, it is identical to Dr. Bill Gray's Hurricane Destruction Potential (HDP) except that I begin the TCI with 34 kts, whereas the HDP calculation begins with 64 kts. It also very similar to the index which NOAA uses in their Atlantic seasonal forecasts--a summation of the square of the velocity--except that I've scaled the TCI to a baseline of 100 kts in order to avoid huge numbers. My reason for including the TCI is that it is independent of the period of data covered. The NTC is a good indicator of overall tropical cyclone activity, but it changes for all years whenever a new baseline period is utilized, whether this is done on a yearly basis or every 5 or 10 years. Thus, for example, 1950's NTC for the 1950-1990 period is not the same as it was for the 1950-2000 period, etc. The TCI correlates very closely with the NTC, however. I calculated correlation coefficients for the NTC vs TCI data sets for several basins, and the two indices always correlated to around 97-98%. Thus, the TCI is an absolute index independent of any average values of the various parameters, yet it correlates well with the NTC as computed by Dr. Gray's rule. C. Southern Hemisphere Basins ----------------------------- Dividing up the Southern Hemisphere tropical cyclogenetical regions is rather problematic. The Northern Hemisphere basins are rather neatly divided geographically by landmasses and regions of very infrequent tropical cyclone formation, but storms form in the Southern Hemisphere in a rather continuous band from the Mozambique Channel off the eastern coast of Africa eastward across the South Indian Ocean, through the seas and gulfs north of Australia, into the Coral Sea and across the South Pacific to the region of French Polynesia well east of the International Dateline. Several different schemes for dividing the Southern Hemisphere into useful basins for statistical purposes have been proposed, but none are completely satisfactory in all respects. For my purposes, I am going to present statistics for various longitudinal regions, some of which overlap. This monthly feature focuses on the Australian Region of warning responsibility between longitudes 90E and 160E. The November, 2003, summary covered the entire Southern Hemisphere and several sub-regions of the South Indian Ocean, while the December, 2003, summary featured the South Pacific Ocean. Due to time constraints, I did not calculate the full regime of parameters for the 2002-2003 season, but I did glean the numbers of NS, H and IH for the various areas, and these are summarized following each table. The four regions covered this month are: (1) Entire Australian Region from 90E to 160E (2) Northwest Australia/Southeast Indian Ocean (90E to 135E) (3) Northeast Australia/Coral Sea (135E to 160E) (4) Gulf of Carpentaria/Arafura and Timor Seas (105E to 142E) Region (1) encompasses the area for which Australia's three TCWCs (Brisbane, Darwin, Perth) have warning responsibility, plus includes the small area covered by the Port Moresby, Papua New Guinea, warning centre. Since longitude 135E rather neatly bisects Australia and also lies just inland from the western shorline of the Gulf of Carpentaria, and given that the frequency of tropical cyclone activity is rather low in that region, the meridian serves as a convenient dividing line between cyclones affecting primarily northeastern Australia and those affecting northwestern Australia. Beginning with the 2000-2001 cyclone season, I have treated the areas east and west of 135E as separate sub-basins in the monthly summaries. Finally, I have included statistics for the zone between 142E and 105E, which covers the seas and gulfs along the northern Australian coastline (Gulf of Carpentaria, Arafura Sea and Timor Sea). D. Tables of Tropical Cyclone Data ---------------------------------- The tropical cyclone data in tabular format follows. The various intensity categories are based on a MSW averaged over 1-minute. This results in slightly higher numbers of cyclones than would be obtained utilizing a 10-minute averaging period, as all the Southern Hemisphere TCWCs do. The year listed in the leftmost column is the year in which the season ends; e.g., 1961 represents the 12-month period from 1 July 1960 through 30 June 1961. (1) ENTIRE AUSTRALIAN REGION (90E - 160E) Year NS H IH NSD HD IHD NTC TCI --------------------------------------------------------------- 1961 9 4 2 52.00 16.25 2.50 95 69 1962 6 0 0 34.50 .00 .00 20 25 1963 15 2 1 40.25 2.25 .25 53 36 1964 11 6 0 43.75 8.50 .00 59 45 1965 9 2 0 37.75 3.00 .00 35 29 1966 9 2 0 28.25 3.00 .00 32 24 1967 13 4 1 50.00 9.50 1.75 78 54 1968 8 2 0 27.75 3.00 .00 30 26 1969 10 0 0 16.50 .00 .00 19 11 1970 8 3 0 29.25 4.00 .00 35 28 1971 13 4 1 54.00 6.50 1.50 74 58 1972 15 10 3 68.00 20.75 2.75 143 95 1973 12 9 1 40.50 17.25 .25 90 62 1974 19 9 0 77.75 15.75 .00 101 83 1975 17 3 3 57.50 10.75 4.75 120 81 1976 16 8 2 67.75 23.00 4.25 142 105 1977 13 5 1 36.25 8.50 .75 69 42 1978 9 4 2 39.50 15.00 3.25 94 65 1979 13 4 1 54.00 12.25 2.00 85 66 1980 12 9 6 66.25 26.50 8.25 201 129 1981 14 7 6 58.25 25.25 8.00 191 111 1982 17 6 2 64.00 8.75 .50 94 67 1983 7 4 1 38.75 12.75 2.25 73 61 1984 18 11 2 56.75 14.25 1.75 123 89 1985 19 11 5 78.50 26.00 3.50 183 120 1986 16 9 3 52.50 18.25 2.25 129 76 1987 9 4 2 35.00 5.25 1.50 69 39 1988 5 4 0 19.50 2.50 .00 29 19 1989 13 6 4 44.75 16.75 6.75 147 85 1990 14 8 1 57.25 15.75 3.50 113 75 1991 11 5 2 50.25 13.25 3.75 104 73 1992 11 9 5 48.75 26.00 8.50 186 110 1993 9 3 2 41.25 9.50 2.25 78 51 1994 14 6 3 46.75 22.00 5.75 142 87 1995 6 5 4 25.25 11.00 3.50 100 47 1996 15 8 3 56.00 16.00 3.50 131 79 1997 17 7 3 73.50 19.50 4.25 146 107 1998 11 6 2 55.75 14.25 2.00 100 75 1999 20 8 5 56.25 19.75 9.25 194 107 2000 13 7 4 54.75 20.00 7.75 164 98 2001 8 3 1 24.00 6.50 1.00 51 31 2002 11 3 1 25.50 5.25 1.75 58 31 Avg. 12.3 5.5 2.0 47.3 12.7 2.8 2002-2003 Season - NS: 10 H: 3 IH: 2 (2) NORTHWEST AUSTRALIA/SOUTHEAST INDIAN OCEAN (90E - 135E) Year NS H IH NSD HD IHD NTC TCI --------------------------------------------------------------- 1961 5 4 2 38.25 16.25 2.50 123 60 1962 4 0 0 30.50 .00 .00 25 23 1963 8 1 1 28.25 1.50 .25 53 26 1964 5 3 0 19.25 4.50 .00 42 21 1965 7 2 0 22.25 3.00 .00 41 19 1966 8 2 0 24.75 3.00 .00 44 22 1967 5 2 0 17.50 3.75 .00 36 17 1968 5 2 0 20.25 3.00 .00 36 19 1969 6 0 0 10.00 .00 .00 18 6 1970 4 2 0 19.25 2.75 .00 33 19 1971 8 3 1 29.75 5.50 1.50 80 36 1972 5 3 1 21.75 6.50 .75 65 31 1973 9 7 1 32.00 15.75 .25 110 53 1974 11 7 0 54.25 10.50 .00 103 58 1975 14 3 3 51.00 10.75 4.75 165 75 1976 8 4 2 37.00 12.75 4.25 137 63 1977 6 4 0 23.75 6.25 .00 55 28 1978 5 4 2 29.75 15.00 3.25 122 58 1979 7 2 0 21.25 1.75 .00 38 19 1980 8 7 5 44.75 20.75 7.75 233 101 1981 12 7 6 49.25 25.25 8.00 266 103 1982 13 3 0 44.25 4.00 .00 72 41 1983 5 3 0 16.50 3.00 .00 38 18 1984 12 6 0 32.00 9.25 .00 86 42 1985 11 8 3 57.25 19.75 1.25 171 88 1986 11 6 3 40.00 13.75 2.25 150 59 1987 5 3 2 23.75 5.00 1.50 81 30 1988 3 2 0 7.25 1.75 .00 22 8 1989 9 4 2 32.50 10.75 2.75 120 54 1990 11 5 1 39.00 12.50 3.50 130 58 1991 8 3 1 30.50 6.75 1.75 85 42 1992 5 5 4 32.25 19.00 7.25 192 77 1993 4 0 0 14.25 .00 .00 16 10 1994 11 4 1 29.00 11.50 1.00 98 43 1995 3 3 3 14.00 7.50 2.50 96 30 1996 12 6 3 40.00 15.00 3.50 165 66 1997 11 4 2 45.75 11.50 2.50 131 62 1998 6 3 1 19.50 7.00 .75 67 30 1999 15 8 5 50.00 19.75 9.25 266 103 2000 11 7 4 47.25 20.00 7.75 228 93 2001 7 3 1 20.75 6.50 1.00 71 28 2002 7 2 1 20.00 4.25 1.75 68 27 Avg. 7.9 3.7 1.5 30.5 9.0 2.0 2002-2003 Season - NS: 6 H: 2 IH: 2 (3) NORTHEAST AUSTRALIA/CORAL SEA (135E - 160E) Year NS H IH NSD HD IHD NTC TCI --------------------------------------------------------------- 1961 4 0 0 13.75 .00 .00 26 9 1962 2 0 0 4.00 .00 .00 10 2 1963 8 1 0 12.00 .75 .00 50 9 1964 7 3 0 24.50 4.00 .00 93 24 1965 4 0 0 16.00 .00 .00 28 10 1966 2 0 0 3.50 .00 .00 10 3 1967 8 2 1 32.50 5.75 1.75 170 37 1968 3 0 0 7.50 .00 .00 17 7 1969 5 0 0 6.75 .00 .00 23 5 1970 4 1 0 10.00 1.25 .00 38 9 1971 7 1 0 24.25 1.00 .00 60 22 1972 10 7 2 46.25 14.25 2.00 311 64 1973 4 2 0 8.50 1.50 .00 47 9 1974 8 2 0 23.50 5.25 .00 92 25 1975 4 0 0 6.50 .00 .00 19 6 1976 8 4 0 30.75 10.25 .00 140 43 1977 7 1 1 12.50 2.25 .75 100 14 1978 4 0 0 9.75 .00 .00 22 6 1979 7 2 1 32.75 10.50 2.00 194 47 1980 5 2 1 21.50 5.75 .50 122 29 1981 3 0 0 9.00 .00 .00 18 8 1982 7 3 2 19.75 4.75 .50 161 26 1983 2 1 1 22.25 9.75 2.25 159 42 1984 7 5 2 24.75 5.00 1.75 214 47 1985 9 3 2 21.50 6.25 2.25 214 33 1986 5 3 0 12.50 4.50 .00 77 17 1987 5 1 0 11.25 .25 .00 38 8 1988 2 2 0 12.25 .75 .00 41 11 1989 4 2 2 12.25 6.00 4.00 216 31 1990 4 3 0 18.25 3.25 .00 74 17 1991 3 2 1 19.75 6.50 2.00 150 31 1992 6 4 1 16.50 7.00 1.25 162 33 1993 6 3 2 27.00 9.50 2.25 225 41 1994 3 2 2 17.75 10.50 4.75 255 44 1995 3 2 1 11.25 3.50 1.00 106 17 1996 5 2 0 16.25 1.00 .00 56 13 1997 7 3 1 27.75 8.00 1.75 182 44 1998 7 3 1 36.50 7.25 1.25 176 45 1999 5 0 0 6.25 .00 .00 22 4 2000 3 0 0 7.50 .00 .00 17 5 2001 3 0 0 3.50 .00 .00 13 3 2002 4 1 0 5.50 1.00 .00 32 4 Avg. 5.1 1.7 0.6 16.8 3.7 0.8 2002-2003 Season - NS: 5 H: 1 IH: 0 (4) SEAS AND GULFS OFF NORTHERN AUSTRALIA (105E - 142E) (Gulf of Carpentaria/Arafura Sea/Timor Sea) Year NS H IH NSD HD IHD NTC TCI --------------------------------------------------------------- 1961 6 4 2 39.00 16.25 2.50 156 61 1962 5 0 0 30.75 .00 .00 33 23 1963 6 1 1 26.75 1.50 .25 58 25 1964 5 3 0 27.25 5.00 .00 59 29 1965 9 2 0 29.25 3.00 .00 60 23 1966 5 1 0 17.00 2.75 .00 36 16 1967 5 2 0 17.50 3.75 .00 44 17 1968 5 0 0 15.25 .00 .00 23 10 1969 5 0 0 10.50 .00 .00 19 6 1970 4 2 0 18.75 2.75 .00 40 19 1971 7 4 1 32.50 6.50 1.50 106 41 1972 6 3 1 18.25 6.25 .75 80 27 1973 10 8 1 26.50 12.00 .25 131 42 1974 9 6 0 39.00 9.25 .00 104 43 1975 9 3 3 33.25 10.75 4.75 178 60 1976 7 3 2 32.00 11.00 4.25 154 56 1977 6 5 1 22.75 8.50 .75 99 33 1978 6 2 1 22.50 8.25 2.75 104 38 1979 6 2 0 17.75 2.00 .00 42 17 1980 8 5 3 30.75 10.50 4.00 176 59 1981 9 5 5 34.00 19.75 6.50 256 77 1982 12 3 1 38.50 4.50 .25 99 37 1983 4 2 0 11.25 2.25 .00 34 13 1984 9 6 1 25.00 9.25 1.50 123 41 1985 12 8 4 42.25 18.50 2.50 226 75 1986 9 4 2 28.75 10.50 2.00 137 44 1987 6 4 2 28.00 5.25 1.50 110 34 1988 0 0 0 .00 .00 .00 0 0 1989 5 4 2 20.75 10.75 2.75 130 44 1990 6 5 1 21.00 8.50 .50 95 29 1991 5 1 0 20.00 3.50 .00 40 24 1992 3 2 2 15.75 8.50 4.75 127 39 1993 4 0 0 14.50 .00 .00 20 10 1994 9 4 1 21.75 7.00 1.00 100 29 1995 4 3 3 16.25 7.50 2.50 121 32 1996 9 5 3 36.75 13.25 3.50 184 61 1997 6 2 0 29.25 3.50 .00 54 29 1998 7 3 1 21.50 6.50 .75 85 31 1999 9 5 4 28.25 11.75 6.75 222 65 2000 9 6 4 29.00 9.50 3.00 182 49 2001 7 2 1 19.25 3.00 1.00 72 21 2002 4 1 1 10.25 3.00 1.75 61 18 Avg. 6.6 3.1 1.3 24.3 6.8 1.5 2002-2003 Season - NS: 7 H: 2 IH: 1 E. Monthly Tropical Cyclone Information --------------------------------------- I did not have the time to attempt to ferret out monthly information regarding tropical cyclone genesis. Patrick Hoareau has already compiled much information on Southern Hemisphere tropical cyclones, including monthly tropical cyclone frequencies, and this can be accessed at the following link: I would encourage those interested in detailed statistics of Southern Hemisphere tropical cyclones to visit the above website. More infor- mation describing Patrick's work can be found in the monthly feature in the February, 2003, summary. ************************************************************************* ACTIVITY BY BASINS ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico Activity for February: No tropical cyclones ************************************************************************* NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180 Activity for February: No tropical cyclones ************************************************************************* NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180 Activity for February: 1 tropical storm ** ** - classified as a tropical storm only by JTWC Northwest Pacific Tropical Activity for February ------------------------------------------------ One tropical cyclone came to life in the Northwest Pacific basin during February, the month of the year with the lowest average number of tropical cyclone formations. JTWC was the only warning agency to classify TC-01W as a tropical storm--all the Asian TCWCs treated it as a tropical depression. (PAGASA assigned the name Ambo when the system briefly entered the eastern extremity of their AOR.) A special thanks to Kevin Boyle for writing the summary for Tropical Storm 01W/Ambo. TROPICAL STORM (TC-01W / AMBO) 11 - 16 February ------------------------------------ A. Storm Origins ---------------- At 2000 UTC on 9 February JTWC issued a STWO on an area of convection located near 5.0N/153.0E, or approximately 250 nm west-southwest of Pohnpei. This area eventually developed into Tropical Storm 01W and was a twin to a disturbance in the Southern Hemisphere which became Tropical Cyclone Fritz. Animated infrared satellite imagery indicated cycling deep convection over a weak LLCC situated within the monsoon trough. Upper-air analyses indicated that the suspect area was located in the southwestern quadrant of the subtropical ridge with good divergence and moderate wind shear conditions. The potential for development for the next 24 hours was assessed as poor, and then upgraded to fair at 11/1300 UTC. At this time animated infrared satellite imagery indicated that the deep convection had persisted and consolidated over the weak LLCC. A TCFA was issued at 11/1500 UTC and soon followed by the first warning on Tropical Depression 01W at 1800 UTC. B. Storm History ---------------- At the time of the first warning, Tropical Depression 01W was located approximately 150 nm south of Agana, Guam, and moving toward the north- west at 12 kts . Deep convection continued to develop over the system and animated satellite imagery showed low-level cloud lines wrapping in from the southeast. After further intensification (and a turn to the west-northwest) TC-01W was upgraded to a 35-kt tropical storm, but the system was still being harassed by wind shear. Multi-spectral satellite imagery revealed an exposed LLCC south of the deep convection which had weakened by 12/1200 UTC, and as a result TS-01W was downgraded back to tropical depression status. By 13/0000 UTC the appearance of TD-01W looked worse for wear with only weak convection situated over a broad LLCC. At 0000 UTC on 13 February the partially-exposed centre of TD-01W was moving west at 15 kts approximately 180 nm north-northwest of Yap. Most of the deepest convection was in the northern quadrants at this time. Things hadn't improved six hours later, but at 13/1200 UTC TD-01W was rewarded for its efforts and persistence. Deep convection began to increase once again and formed an impressive albeit sheared CDO as seen in 13/1800 UTC satellite images. TD-01W was re-upgraded to a tropical storm with the MSW increased to 40 kts. The system began to slow and meander toward the north-northwest under the steering influence of the low to mid-level ridge located to the northeast. (Note: Tropical Storm 01W was named Ambo by PAGASA, which issued only four warnings on this system from the 13th to the 14th.) At 0000 UTC on 14 February Tropical Storm 01W (Ambo) had slowed to 5 kts, still trekking toward the north-northwest approximately 380 nm north-northwest of Yap. The system managed to strengthen a little more and the MSW reached a peak intensity of 45 kts at 14/0600 UTC. This was maintained for another six hours before TS-01W was abruptly down- graded to a tropical depression at 14/1800 UTC. At this time upper- level shearing had exposed the LLCC again with the nearest deep convection located over 65 nm away. Pressures had been building across the northern Philippines and this synoptic feature prevented the weak tropical cyclone from making any further progress toward the north. Instead, a very slow east-northeastward crawl had begun and this had turned east-southeastward by 15/0000 UTC. Satellite images at 0000 UTC 15 February continued to show deep convection well-removed from the LLCC which, at this time, was located some 325 nm north-northwest of Yap. The intensity of TD-01W was hovering at 30 kts. Water vapour imagery at 0600 UTC showed a ball of deep convection developing over the LLCC, but this soon waned. Movement was slow throughout the day and toward the east or east-southeast, then south-southwestward at 15/1800 UTC as the ridge began to pull the system in toward the central Philippines. By 16/0000 UTC TD-01W had finished its clockwise loop cycle and was accelerating south-southwestward at around 13 kts with the limited areas of deep convection mainly to the northwest of the exposed centre. JTWC issued the final advisory at 06/0600 UTC on the understanding that the system would continue to track through a poor sustenance environment, and by 1800 UTC satellite images showed hardly any trace of the tropical cyclone. (Editor's Note: JTWC was the only warning agency to upgrade TD-01W/Ambo to tropical storm status.) C. Ambo's Afterlife? -------------------- JTWC continued to monitor the remnants of TS-01W through STWOs, and at 2330 UTC on 17 February considered the development potential to be fair based on the increase of deep convection near the remnant LLCC, which had drifted southwestward to a position approximately 395 nm east of Mindanao, Philippines. This was downgraded to poor after the centre once again became fully-exposed to the east of the cycling deep convection. According to JMA's bulletins issued on the 17th the weak LOW was at a virtual standstill and remained stationary until late on the 18th when it began to drift slowly west. Further bursts of deep convection occurred as the system continued its way west at a quicker pace through the 19th, but at 20/0600 UTC JTWC ceased mentioning the remnants of TC-01W in their STWOs as the appearance and organization of the system deteriorated again. What little convection remained in association with the wreckage of TD-01W continued to drift west towards the Philippines, but generally it came and went for several days. In fact, satellite images showed the disturbance re-organizing on the 23rd (although it was still being sheared) by which time it was moving northwestward and paralleling the east coast of the Philippines. On the 24th the system became exposed again. However, following another redevelopment phase early on the 25th, several bursts of deep convection appeared forming a cold CDO. Embedded within the overcast was a "pinhole" eye feature which appeared in satellite images for two hours. Shortly afterwards, cloud top temperatures warmed and the disturbance was completely stripped of convection by upper-level shearing. Accelerating towards the northeast the disturbance completely dissipated and had been absorbed into a frontal system by 0000 UTC on 27 February. (In an e-mail, Roger Edson noted that he'd carefully looked at satellite imagery of the pinhole eye feature referenced above, but could not discern any rotation. Without rotation of the cloud system, of course, the feature would not have been a true eye.) This disturbance may be at least partially related to the remnants of TC-01W/Ambo, and satellite animations covering the period after Ambo's dissipation certainly suggest that it was the rejuvenation of Ambo. (Huang Chunliang pointed out that only CWB was following the system as a LOW during the time that the "eye" was seen and that CPHC was the only agency to classify the disturbance as a weak depression and to mention the fact that it had intensified during the previous 12 hours. (JMA at the time was following another LOW centre further to the south.) D. Damage and Casualties ------------------------ There were no reports of damages or loss of life in association with Tropical Storm 01W/Ambo. (Report written by Kevin Boyle) ************************************************************************* NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea Activity for February: No tropical cyclones ************************************************************************* SOUTHWEST INDIAN OCEAN (SWI) - South Indian Ocean West of Longitude 90E Activity for February: None Southwest Indian Ocean Tropical Activity for February ----------------------------------------------------- As the month of February opened, Severe Tropical Storm Elita was gathering strength over the Mozambique Channel prior to its third crossing of the island of Madagascar while intense Tropical Cyclone Frank was slowly chugging southward over the central South Indian Ocean. The complete reports on these two storms can be found in the January tropical cyclone summary. After Elita and Frank had run their courses, the remainder of the month of February lay unusually quiet across the South- west Indian Ocean with no tropical disturbances entering warning status from either MFR or JTWC. ************************************************************************* NORTHWEST AUSTRALIA/SOUTHEAST INDIAN OCEAN (AUW) - From 90E to 135E Activity for February: 1 tropical LOW 1 severe tropical cyclone (hurricane) Northwest Australia/Southeast Indian Ocean Tropical Activity for February ------------------------------------------ Two tropical weather systems traversed the waters of the Timor Sea off Western Australia during February. An overland system began to show signs of intensification near the Kimberley coast around 8 February. The LOW moved westward and was over the Timor Sea by the next day. Although forecast to develop into a tropical cyclone for several days, the LOW remained fairly weak and eventually made landfall along the Pilbara coastline east of Port Hedland around 0000 UTC on the 12th. Late in the month another tropical LOW began strengthening off the Kimberley coast. This one was destined to develop into Severe Tropical Cyclone Monty, which reached intense tropical cyclone status with peak winds estimated at 95 kts on the 29th (110 kts 1-min avg MSW per JTWC). The storm turned southward toward the coast and made landfall on 1 March near Mardie as a severe Category 3 cyclone on the Australian Cyclone Severity Scale with peak gusts estimated near 110 kts at landfall. The report below on Monty was written by Simon Clarke--a special thanks to Simon for his assistance. SEVERE TROPICAL CYCLONE MONTY (TC-14S) 26 February - 2 March ------------------------------------------------- A. Storm Origins ---------------- Monty was the fourth tropical cyclone of the 2003/2004 season to be named by the Perth Tropical Cyclone Warning Centre. It was first detected on 26 February 2004 over land in the western Kimberley region approximately 140 kilometres east of Broome as a westward-moving tropical disturbance. Moving at 6 knots, the developing circulation moved seawards to the south of Broome later in the day. In the ensuing 24-hour period, deep convection associated with the LLCC increased under conditions of low to moderate upper-level wind shear and enhanced upper-level outflow in all quadrants. The developing storm was upgraded to tropical cyclone status at 1800 UTC on 27 February near 19.2S/119.7 E, or about 90 nautical miles northeast of Port Hedland, and named Monty. B. Storm History ---------------- Following naming, Monty travelled in a general westerly direction approximately 50-75 nautical miles offshore along the Western Australian coastline for the following 48 hours, initially moving toward the west-northwest, and then west-southwest, along the periphery of a mid-level steering ridge located to the south. During this period and under favourable poleward and equatorial outflow, Monty steadily intensified, and by 29/1000 UTC had reached Category 4 status on the Australian scale with a central pressure of 935 hPa and maximum winds of 95 knots (10-min avg) near the centre. JTWC's corresponding 1-min avg MSW estimate was 110 knots--in very good agreement with Perth. The severe cyclone was located near 19.8S/ 115.6E at the time, or 90 nautical miles northwest of Karratha and 115 nautical miles north-northeast of Onslow. Monty remained close to this intensity for a further 12 hours as the cyclone moved to near 20.2S/115.2E at 2200 UTC on 29 February. At this time, an approaching short-wave trough weakened the mid-level steering ridge. Monty commenced its poleward turn towards the Australian coastline around the western periphery of a mid-level subtropical ridge now located to the southeast of the system. Settling into a southerly, and ultimately a southeasterly trajectory, Monty some lost strength, but remained an intense Category 3 cyclone passing to the near north of Barrow Island before crossing the coastline near Mardie during the late evening hours of 1 March 2004 (local time). At the time of landfall, Monty had estimated 10-min avg winds of 80 knots and a central pressure of 955 hPa. After crossing the coast, the cyclonic circulation decayed considerably as Monty travelled inland to the southeast. Approximately 24 hours after landfall, and after travelling some 300 kilometres inland, Monty was downgraded from tropical cyclone status near 24.2S/118.0E. The remnant depression continued to track toward the southeast prior to dissipation over land in the central part of Western Australia. C. Warnings ----------- Monty remained within the Perth Tropical Cyclone Warning Centre's AOR for its entire life. During this period, the Centre issued Tropical Cyclone advices on 68 occasions, beginning at 0100 UTC on 27 February and with the final one issued at 1900 UTC on 2 March. D. Meteorological Observations ------------------------------ The Perth Bureau of Meteorology has issued a report on Monty that can be found at: This report provides an excellent snapshot of interesting observations relating to the cyclone, including wind gusts, lowest reported pressure readings, a pictorial representation of Monty's track, radar images, rainfall accumulations and pictures of flooding produced by the cyclone. Some of the more notable observations include: (1) Highest Wind Gusts ---------------------- 113 kts North Rankin Platform 0600 UTC 29 Feb 95 kts Varanus Island 0717 UTC 01 Mar 91 kts Barrow Island 0940 UTC 01 Mar 83 kts Mardie Station 1110 UTC 01 Mar (2) Lowest Pressures -------------------- 960.6 hPa Varanus Island 0600 UTC 01 Mar 963.7 hPa Barrow Island 0730 UTC 01 Mar 964.1 hPa Mardie Station 1620 UTC 01 Mar (3) Accumulated Rainfall ------------------------ 393 mm Mardie Station (under reported--rain gauge overflowed) 382 mm Yalleen 323 mm Roebourne E. Damage and Casualties ------------------------ There were no casualties reported as a direct consequence of Monty. In fact, little serious damage was recorded. Prior to landfall, the cyclone forced 'resources giant' Rio Tinto to shut one-third of its mines and one of its ports in the region. The company's Dampier port, which normally operates 24 hours a day and moves an estimated 203,000 tons of iron ore daily, was closed during the event. For large parts of Western Australia's pastoral country, Monty produced the best rains in four years, if not a decade, particularly in the central and western parts of the Pilbara and Gascoyne. The Fortescue River rose to its highest level since 1975. There were media reports of people being caught by rising waters. At Yaraloola station, south of Karratha, two residents and their dogs were plucked off their roof by a helicopter with flood waters reaching halfway up the walls. The flooding from Monty's rains cut major highways, including North West Coastal Highway, for two weeks. Emergency services had to fly fresh water and supplies into inland towns such as Pannawonica, where all telephone landlines were down after the storm. Further information, including satellite imagery, track details and photographs of the event can be found at the following web-links: (Report written by Simon Clarke) ************************************************************************* NORTHEAST AUSTRALIA/CORAL SEA (AUE) - From 135E to 160E Activity for February: 1 tropical cyclone Northeast Australia/Coral Sea Tropical Activity for February ------------------------------ One named tropical cyclone developed between longitudes 135E and 160E during the month of February. Tropical Cyclone Fritz developed east of the Cape York Peninsula on the afternoon of 10 February and moved inland near Bathhurst Bay during the morning of the 11th with peak gusts estimated at 55 kts. The cyclone weakened over land but later re-intensified into a cyclone over the Gulf of Carpentaria on the morning of 12 February, making a second landfall during the night of 12-13 February along the southern Gulf coastline. As the month of February closed, another tropical LOW was slowly gaining strength in the Gulf of Carpentaria. On 1 March this system developed into Tropical Cyclone Evan shortly before making landfall in the Northern Territory. Evan will be covered in next month's summary. A special thanks to Simon Clarke for writing the following report on Tropical Cyclone Fritz. TROPICAL CYCLONE FRITZ (TC-12P) 8 - 12 February ------------------------------------------ A. Storm Origins ---------------- The first week of February, 2004, saw an active monsoon trough become established through the northern Coral and Solomon Seas. Initially, a slow-moving tropical LOW developed in the central Solomon Sea at approximately 9.0S/154.0E on 8 February 2004. This location is about 350 nautical miles west of Honiara. Gale warnings were issued for this LOW as it deepened to 1003 hPa. However, strong upper-level northeasterly winds weakened this initial development within 24 hours as a new LOW developed to its southwest in the northern Coral Sea. This new LOW became Queensland's first named storm of the 2003/2004 season. The new tropical LOW developed rapidly, and at 10/0600 UTC a gale warning was issued for the northern Coral Sea adjacent to the LOW which at the time was located near 13.7S/147.3E, or about 165 nautical miles northeast of Cooktown. At 10/0900 UTC the tropical LOW was upgraded to tropical cyclone status and named Fritz. B. Storm History ---------------- At the time of naming, Tropical Cyclone Fritz was centred near 14.0S/146.6E (or about 125 nautical miles east of Cape Melville and 120 nautical miles northeast of Cooktown) with a central pressure of 998 hPa, moving to the west at 11 knots. Fritz maintained a fast-paced track (between 11 and 16 knots), generally toward the west, and crossed the far northern Queensland coastline at 10/1540 UTC, just to the south of Cape Melville (14.5S/ 144.7E). At the time of landfall, Fritz sported a 995 hPa central pressure with peak 10-min avg winds estimated at 40 knots. It was clear that Fritz would cross the Cape York Peninsula rapidly with the opportunity for redevelopment in the southwestern Gulf of Carpentaria. The Bureau of Meteorology, Brisbane, had anticipated this event and was already issuing cyclone advisories for the south- western Gulf communities. As predicted, Fritz quickly lost tropical cyclone characteristics as it crossed the Cape York Peninsula, but quickly regained them as it entered the Gulf of Carpentaria just after 1400 UTC on 11 February. A microwave TRMM image at 1419 UTC depicted a clear centre near 16.4S/141.1E, just off the coastline. By 11/1545 UTC Fritz had been renamed and had commenced re-intensification under favourable conditions of warm sea surface temperatures, minimal wind shear and good upper-level outflow. Fritz moved generally toward the west-southwest at 11 knots. As Fritz approached Mornington Island, it nudged onto a westerly path and deepened to 985 hPa (peak intensity) with winds gusting to 75 knots, implying peak 10-min avg winds of around 50 knots. At the time radar imagery clearly showed evidence of an eye, which passed over the island between 12/0200 UTC and 12/0600 UTC. Fritz slowed as it approached the Australian mainland near 16.8S/138.8E at 12/1200 UTC and reverted to a west-southwesterly path. Fritz rapidly degenerated after crossing the coast. Following degeneration, ex-Tropical Cyclone Fritz maintained a clear satellite signature as it travelled across inland Northern Territory and Western Australia before interacting with a cold front south of Perth, where a deep LOW resulted (eventually reaching the southern tip of New Zealand as a 963 hPa LOW some days later). C. Damage/Casualties/Observations --------------------------------- Fritz crossed the coastline in relatively remote parts of Australia. Jeff Callaghan from the Bureau of Meteorology Brisbane provides the following (slightly edited) insight: "Fallen trees caused water and power outages at the remote communities of Wujal Wujal, Bloomfield and Ayton north of Cairns. Landslides closed the Gillies Highway near Cairns, and a landslide caused major damage to properties at Yorkeys Knob (northern beach suburb of Cairns). Cape Flattery AWS (14.96S/145.3E) registered 10-minute mean winds SE/31 knots around 1122 UTC, 10 February 2004, when Fritz was 80 km north of the AWS. "Rainfalls in the 24 hours to 9 AM 11 February (2300 UTC 10 February 2004) include: 204 mm Weipa (Cape York Peninsula) 173 mm Saddle Mountain (near Cairns) 163 mm Cairns Airport Alert "Heavy rains continued in the Cairns Townsville Mackay Region with 24-hour totals to 9 AM 12 February 2004: 309 mm Upper Murray 292 mm Paluma 193 mm South Johnstone 184 mm Innisfail "There was flash flooding in the Innisfail/South Johnstone region with falls of 74 mm in one hour. "At Mornington Island trees were uprooted but there was no structural damage. The island has withstood direct hits from severe Tropical Cyclones Warren and Abigail over the last decade and buildings are constructed to withstand severe tropical cyclones. The lowest barometer reading at Mornington Island was 993.3 hPa at 0330 UTC, 12 February, when the winds around this time were ESE/21 knots, gusting to 39 knots. Buildings and trees heavily surround the anemometer on the island, and it is customary for forecasters at the Townsville Meteorological Office to relate the 10-minute mean wind to the maximum gust. Sweers Island (17.2S/139.6E) estimated 10-minute mean winds of 45 knots in a special report at 2330 UTC, 11 February 2004, when a rainband south of the centre passed over the Island." There were no casualties as a consequence of Tropical Cyclone Fritz. D. Comparisons (BoM & JTWC) --------------------------- Compared to the Bureau of Meterology (BoM), the Joint Typhoon Warning Centre (JTWC) was slow to pick up Fritz. This could perhaps be attributed to the time lapsing between warnings and the rapid development of Fritz following initial identification. Similar occurrences have also been observed in previous seasons in the Coral Sea: Tropical Cyclones Rona, Tessi, Vaughan, Steve and Abigail (and later Evan in the Gulf of Carpentaria), were small, minor to moderately intense tropical cyclones that were significantly under-estimated in their intensity. (Report written by Simon Clarke with significant contributions by Jeff Callaghan) ************************************************************************* SOUTH PACIFIC (SPA) - South Pacific Ocean East of Longitude 160E Activity for February: 1 intense tropical cyclone South Pacific Tropical Activity for February -------------------------------------------- Following the very intense and devastating Tropical Cyclone Heta in early January, the South Pacific east of 160E lay rather quiet for almost two months with no tropical cyclones or depressions tracked. During the third week of February a system began developing to the northwest of Fiji which would become intense Tropical Cyclone Ivy. After moving westward, Ivy turned to the south on a course which would take it over some of the islands of the Republic of Vanuatu, including the capital city of Port Vila, near the time of its peak intensity of 90 kts (110 kts 1-min avg MSW per JTWC). Ivy then accelerated to the southeast and narrowly missed New Zealand's North Island shortly after it had made the transition into a still-potent extratropical cyclone. The following report on Ivy was written by Simon Clarke--a special thanks to Simon for his assistance. TROPICAL CYCLONE IVY (TD-05F / TC-13P) 21 - 29 February 2004 ----------------------------------------- A. Storm Origins ---------------- Ivy was the second tropical cyclone to form in RSMC Nadi's area of responsibility during the 2003/2004 South Pacific tropical cyclone season. A tropical disturbance was first identified about midway between Nadi, Fiji, and Port Vila, Vanuatu, along an active monsoon trough on 21 February 2004. The next day, the disturbance formed into a depression, with the LLCC clearly exposed and displaced just southeast of the deepest convection. Around this time, the depression began to move slowly west- northwestward while still significantly influenced by shear and diurnal variations. On the 23rd convection about the LLCC gradually increased with improved organization. Outflow was good to the north and developing in all other quadrants. By 23/0000 UTC the LLCC had slipped under the cooling deep convection. Situated under an upper- level outflow region with minimal shear, TD-05F was then named Tropical Cyclone Ivy at 23/0300 UTC as primary convective bands increasingly wrapped tightly around the central features. At the time of naming, Ivy was located approximately 275 nautical miles northeast of Port Vila, Vanuatu, and moving slowly northwestward. B. Storm History ---------------- Initially the system had intensified sporadically, but after being named intensification was steady with Ivy attaining storm intensity 15 hours later while located some 250 nautical miles north-northeast of Port Vila and still maintaining a northwesterly motion. By 24/0000 UTC, the cyclone had shifted onto a southwesterly track, retreating around a mid-level ridge on a path towards the central part of Vanuatu. Hurricane intensity was reached at approximately 24/1200 UTC with the storm located 210 nautical miles due north of Port Vila as it continued trekking toward the southwest. Occasional warm air entrainment, together with the disruption from frictional interference from the rugged terrain of the Vanuatu island group, inhibited further intensification. Ivy peaked at approximately 26/0000 UTC at 90 knots maximum (10-minute average) winds. At its peak Ivy possessed an estimated central pressure of 935 hPa and was located about 30 nautical miles northwest of Port Vila under a strengthening northwesterly steering field. The cyclone began to gather speed and passed very close to Port Vila around 26/0600 UTC. Ivy accelerated towards the south-southeast, keeping just west of the southern islands of Vanuatu whilst weakening under increasingly aggressive vertical wind shear. (Note: JTWC's peak estimated 1-min avg MSW of 110 knots agrees very well with Nadi's peak 10-min avg MSW of 90 knots.) The TCWC at Wellington assumed primary responsibility for further warnings on Ivy after 27/1800 UTC. Ivy had become extratropical by 28/1200 UTC but remained rather potent as it passed close to the east of East Cape, New Zealand, on 29 February as a vigorous extra- tropical cyclone. Following its brush with New Zealand, ex-Tropical Cyclone Ivy continued racing southeastward and had reached the 50th parallel by 0000 UTC on 1 March. C. Warnings ----------- The following warning summary was provided by Alipate Waqaicelua, Chief Forecaster at the Nadi TCWC (slightly edited): "Twenty-five International Marine Warnings were issued on Tropical Cyclone Ivy by RSMC Nadi. These warnings consisted of three Gale Warnings, one Storm Warning and 21 Hurricane Warnings, all issued at six-hourly intervals. In addition, twenty-two Tropical Disturbance Advisories were issued. Specifically for Vanuatu, twenty Special Advisories were released by RSMC Nadi." The Wellington office also issued further warnings until Ivy had lost its tropical cyclone characteristics soon after moving into their area of responsibility. Regular marine warnings were issued for the resulting extratropical storm until it had moved south of latitude 50S. D. Meteorological Observations ------------------------------ A 70-knot surface wind was reported on Aneityum Island (Vanuatu) at 26/1800 UTC. This was the highest surface wind known to have been reported at the time of writing this article. The lowest barometric pressure known to have been recorded was 961.8 hPa at Bauerfield (Vila) at 26/0600 UTC when the cyclone's eye passed directly over the airfield (or close by). However, satellite imagery indicated (through Dvorak analysis) that the minimum pressure could have been as low as 940 hPa when the eye was over the open sea. The highest recorded 24-hour rainfall reported from stations in the path of Ivy was 254.4 mm at Bauerfield on 26 February. E. Damage and Casualties ------------------------ Ivy was an intense tropical cyclone with maximum 10-minute average winds of about 90 knots. Much of Vanuatu received moderate to severe damage directly from the cyclone. The hardest hit areas were the central islands where moderate to severe damage was experienced. There was one fatality. Areas worst affected were the islands of Paama, Epi, Ambrym, the eastern coast of Malekula and the northern tips of Ambae (Aoba) and Maewo. More than 2,000 people had to be evacuated from their homes in the Port Vila area as the eye of Ivy passed directly over or close to the capital. Many of the 24,000 residents of Vanuatu's central islands lost their homes. Most, if not all, of the mango and banana industries were severely damaged, and around 75% of the coconut and cocoa crops were affected. A New Zealand Air Force Orion reported moderate to severe damage to villages in a 40-kilometre circle centred on the southwest of Ambrym Island. Houses lost roofs, and trees and vegetation were flattened. Imagery of Tropical Cyclone Ivy can be found at: More specific damage reporting can be found at Relief Web as follows: No reports of damage have been received, at the time of writing this report, from New Caledonia or the outlying islands in the southeastern Solomon Islands. (Report written by Simon Clarke with significant contributions by Alipate Waqaicelua) ************************************************************************* EXTRA FEATURE In order to shorten the amount of typing in preparing the narrative material, I have been in the habit of freely using abbreviations and acronyms. I have tried to define most of these with the first usage in a given summary, but I may have missed one now and then. Most of these are probably understood by a majority of readers but perhaps a few aren't clear to some. To remedy this I developed a Glossary of Abbreviations and Acronyms which I first included in the July, 1998 summary. I don't normally include the Glossary in most months in order to help keep them from being too long. If anyone would like to receive a copy of the Glossary, please e-mail me and I'll be happy to send them a copy. ************************************************************************* AUTHOR'S NOTE: This summary should be considered a very preliminary overview of the tropical cyclones that occur in each month. The cyclone tracks (provided separately) will generally be based upon operational warnings issued by the various tropical cyclone warning centers. The information contained therein may differ somewhat from the tracking and intensity information obtained from a "best-track" file which is based on a detailed post-seasonal analysis of all available data. Information on where to find official "best-track" files from the various warning centers will be passed along from time to time. The track files are not being sent via e-mail. They can be retrieved from the archive sites listed below. (Note: I do have a limited e-mail distribution list for the track files. If anyone wishes to receive these via e-mail, please send me a message.) Both the summaries and the track files are standard text files created in DOS editor. Download to disk and use a viewer such as Notepad or DOS editor to view the files. The first summary in this series covered the month of October, 1997. Back issues can be obtained from the following websites (courtesy of Michael Bath, Michael V. Padua, Michael Pitt, and Chris Landsea): Another website where much information about tropical cyclones may be found is the website for the UK Meteorological Office. Their site contains a lot of statistical information about tropical cyclones globally on a monthly basis. The URL is: TROPICAL CYCLONE REPORTS AVAILABLE JTWC now has available on its website the complete Annual Tropical Cyclone Report (ATCR) for 2002 (2001-2002 season for the Southern Hemisphere). ATCRs for earlier years are available also. The report for the 2002-2003 Southern Hemisphere season has also recently been added. The URL is: Also, TPC/NHC has available on its webpage nice "technicolor" tracking charts for the 2003 Atlantic and Eastern North Pacific tropical cyclones; also, storm reports for all the 2003 Atlantic and Eastern North Pacific cyclones are now available, as well as track charts and reports on storms from earlier years. The URL is: A special thanks to Michael Bath of McLeans Ridges, New South Wales, Australia, for assisting me with proofreading the summaries. PREPARED BY Gary Padgett E-mail: garyp@alaweb.com Phone: 334-222-5327 Kevin Boyle (Eastern Atlantic, Western Northwest Pacific, South China Sea) E-mail: newchapelobservatory@btinternet.com Huang Chunliang (Assistance with Western Northwest Pacific, South China Sea) E-mail: huangchunliang@hotmail.com Simon Clarke (Northeast Australia/Coral Sea, South Pacific) E-mail: saclarke@iprimus.com.au ************************************************************************* ************************************************************************* Published: 05.28.04 / Typhoon2000.ph, Typhoon2000.com