south west indian_ocean cyclone season south west indian_ocean cyclone season quiet season fourth lowest number days tropical storm tropical cyclone activity storms formed far eastern portion basin storms crossing adjacent australian basin east result storms impacted madagascar landfall african continent season normal sea surface temperatures indian_ocean east madagascar february typically peak activity island recorded highest average monthly pressure generally unfavorable conditions tropical storms tracked france office tropical cyclones storm winds mph activity began late tropical storm forming january latest recorded time formed favorable areas tropical cyclogenesis season brought rainfall southwestern madagascar previously dry conditions tropical storms originated crossed adjacent australian basin storms monitored tropical storm tropical cyclone brought beneficial rainfall storm caused drowning deaths caused crop damage strongest storm peaked strong cyclone australian weakened crossing minute maximum sustained winds mph basin final storm unnamed crossing australian basin april minimal tropical storm quickly dissipating tropical disturbances depressions short lived formed september northeastern portion basin tropical depression february approached tropical storm status season summary france office island issued warnings tropical cyclones basin season agency estimated intensity dvorak technique warned tropical cyclones region coast africa south equator joint united_states navy united_states_air_force task force issued tropical cyclone warnings region wind estimates basins world sustained minutes estimates united_states based sustained minute minute winds times minute winds storms formed dissipated tropics exception severe tropical storm season atmospheric conditions shifted despite shift season similarly inactive predecessor general sea surface temperatures normal atmospheric pressures normal unfavorable tropical cyclogenesis month february average peak time activity general lack convection thunderstorms east madagascar average monthly pressure highest reliable records began low number storms occurred despite active cyclone year southern hemisphere summary season described lack activity rare remarkable possibly related walker circulation agency monitored tropical disturbances tropical depressions hours intensified tropical storms average attained tropical cyclone status half average days storm tropical cyclone activity average time fourth lowest reliable record keeping began advent satellite imagery seasons lower number storm days storms severe tropical storm subtropical depression exited area convection formed region january fluctuated intensity days passing cold increased convection january split low pressure area days later subtropical disturbance formed offshore classified extratropical origins lack centralized convection system remained nearly stationary convection extending east january reclassified system tropical depression thunderstorms increased near center increasing organization moderate decreasing wind shear time depression begun eastward movement soon turned south weakness high pressure areas late january depression intensified convection organized central dense overcast day began tracking system tropical cyclone marked unusually late start named storm time latest record anticipated strengthening attained tropical storm status time upgrade passed west sustained winds reached mph gusts strong mph building ridge southeast madagascar turned storm southwest increase wind shear diminished convection discontinued advisories january thunderstorms redeveloped following unexpected decrease wind shear turned southeast ahead approaching trough developed ragged eye feature january day estimated peak minute winds mph estimated minute winds mph equivalent minimal hurricane agency reissued advisory storm peak accelerated southeast gradually lost tropical characteristics extratropical january absorbed approaching cold following rainfall earlier subtropical depression dropped rainfall southwestern madagascar rainfall caused flooding affected thousands people rainfall beneficial previously dry conditions prevented crops planted passage storm caused temperatures decrease madagascar moderate tropical storm january tropical disturbance formed australian region kilometres south indonesian island java moving west southwestward system intensified tropical storm january attained tropical cyclone status days later passing south subsequently increase wind shear induced steady weakening causing circulation briefly exposed convection january maintained area convection nearby circulation exited south west indian_ocean january minimal tropical storm time renamed storm storm turned west west northwest building ridge south increasing wind shear weakened tropical depression status january tropical disturbance day convection intermittent circulation dissipated february moderate tropical storm soon exited australian region tropical disturbance formed north january initially weak gradually organized disturbance tracked quickly west westward powerful ridge south remaining tandem tropical storm east january system crossed south west indian_ocean fast forward motion caused effects wind shear diminish increase circulation strength depression intensified tropical storm january time storm attained peak intensity mph immediately convection began weakening lukewarm water temperatures weakened tropical depression status february continuing rapidly west circulation exposed convection february increased wind shear time passed north island shortly weakened tropical disturbance day circulation passed north mauritius presenting structure strongest winds south dissipated february southeast coast madagascar produced wind gusts mph rainfall total rainfall proving beneficial previously dry conditions despite tropical disturbance produced wind gusts kilometres hour mph mauritius mph mountainous peaks rainfall rates islands varied greatly peak total mauritius compared peak heights island hour rainfall total wet weather persisted dissipated resulting day totals drought conditions mauritius intense tropical cyclone extended period activity indian_ocean convergence zone rebuilt end february spawned area convection march extreme eastern portion basin day circulation noted satellite imagery northeast convection indicated tropical disturbance developed influence monsoon trough steered disturbance southeast australian basin moderate wind shear prevented quick development building ridge south turned system southwest bringing south west indian march tropical depression decreasing wind shear depression slowly intensified convection increased tropical storm march eye developed day signaling intensified tropical cyclone reaching minute winds mph march intense tropical cyclone sustained minute winds mph time estimated peak minute winds mph continuing quickly west southwest moved area cooler waters began weakening march system passed northwest minimal tropical cyclone day intensified slightly winds mph near intensity eyewall crossed mauritius passing island eye increased diameter deteriorating march passed southeast severe tropical storm day storm slowed forward motion rapidly weakened increasing wind shear tropical depression march circulation turned northeast later west trade winds looped east coast madagascar eventually dissipating march affected weakening storm limited wind gusts mph rainfall moving mauritius days cyclone produced peak wave height island airport recorded peak gust mph strong cause crop damage people rainfall peaked failed break island worst drought wind gusts peaked mph rose produced wave heights saint rainfall highest southern portion island mainly process lift hour period precipitation recorded highest total island center storm slow movement produced scattered rainfall days people drowned rainfall proved beneficial dry conditions gusty winds damaged sugar cane banana crops overall damage minor intense tropical cyclone march area convection formed monsoon trough australian basin gradually organizing tropical storm moving west southwestward given march storm attained tropical cyclone status continued strengthen warm waters peak march developed defined eye circular central dense overcast estimated peak minute winds mph estimated maximum minute winds mph equivalent category saffir simpson hurricane wind scale subsequently encountered combination wind shear cooler dry air caused weakening april cyclone crossed south west indian_ocean minute winds mph time renamed continuing west southwest entering basin gradually weakened eye gradually dissipated soon encountered cooler waters southern indian affected previous storms april weakened tropical cyclone status hours peak intensity time circulation exposed deepest convection track shifted west april weakened tropical depression status days later system turned south moving circular track island remaining far away cause effects april circulation turned east dissipating days later south moderate tropical storm april area convection persisted near border south west indian australian regions system moved eastward australian basin tropical disturbance april turning southeast system gradually organized convection persisted april disturbance intensified tropical storm named shortly ridge south turned storm southwest estimated peak winds mph began quickly weakening increasing wind shear april storm crossed south west indian basin maintaining minute winds mph classified system tropical storm storm remained unnamed referred tropical storm system weakened tropical depression status hours entering basin dissipating april storms time cyclone season began august cyclone season southern hemisphere began july agency tracked short lived tropical storm end july classifying tropical cyclone named tropical depression estimating peak minute winds system season proper originated area convection early september northeast portion basin september initiated advisories tropical disturbance east system tracked westward issued september failing intensify winds mph disturbance dissipated september later month formed similar region monsoon trough initiating advisories september day began issuing advisories day upgraded system tropical storm status strong wind shear prevented intensification quickly discontinued advisories continued tracking upgrading system tropical storm status october shear increased storm weakened dissipating october november rapidly weakening moved australian basin dissipated immediately entering south west indian_ocean november december short lived tropical disturbance classified subsequently drifting australian region possibly related previous system moved australian basin basin december quickly dissipating storms january area convection persisted associated circulation located land system drifted east southeast warmer waters gradually organizing january classified system tropical disturbance near coastline disturbance accelerated southeast passing southwest madagascar structure convection eastern periphery strong wind shear heavy rainfall occurred southwest madagascar coast peaking hour period wind gusts reached mph disturbance maximum sustained minute winds mph disturbance transitioned subtropical depression january soon extratropical accelerating southeastward extended period quiet conditions basin area low pressure persisted eastern coast convection fluctuated daily persistent february day thunderstorms organized circulation formed southeast tropical disturbance forming system moved southward developing central dense overcast northeasterly outflow based organization disturbance intensified tropical depression february gale force winds southwest periphery circulation located northern edge convection depression neared tropical storm intensity increase wind shear nearby trough prevented intensification estimated peak minute winds mph making system tropical storm assessment building ridge south turned depression northeast bringing system near station island recorded sustained winds mph gusts mph hours closest approach observations suggested depression tropical storm soon associated convection dissipated circulation turned westward crossing path depression dissipated february close developed similar previous depression tropical disturbance developed initially subtropical nature february cold exited african coast spawning area convection weak low pressure area developed february proceeded southeastward unfavorable wind shear system failed organize initially produced strong wind gusts february convection removed circulation looped southwestern madagascar turn west march named disturbance renamed day circulation executed small loop dissipating march eastern long lived system developed february australian region south february moved westward march initiated advisories system tropical cyclone briefly estimating peak minute winds mph day soon system weakened tropical depression crossing south west indian_ocean late march time designated continuing westward northern edge strong ridge disturbance failed intensify easterly wind shear ceased issuing advisories noted distinct circulation persisted reaching location north mauritius march day turned east sporadic area convection influenced larger days later system organized tropical disturbance system failed dissipated march tropical disturbance named formed march eastern portion basin initially failed develop increase convection system intensified tropical depression march moving generally west northwestward day system began drifting southwest weak steering currents march initiated advisories system tropical cyclone briefly upgrading tropical storm status day march depression began weakening dissipating days later storm names tropical disturbance named reaches moderate tropical storm strength tropical disturbance reaches moderate tropical storm status west sub regional madagascar assigns appropriate storm tropical disturbance reaches moderate tropical storm status sub regional mauritius assigns appropriate storm new annual list year list provided country
1998–99 South-West Indian Ocean cyclone season