dom

底層眼牆建立，JTWC初報上望70節

WTXS31 PGTW 210300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 29S (JOBO) WARNING NR 001//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/200821ZAPR2021//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. TROPICAL CYCLONE 29S (JOBO) WARNING NR 001   
   01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   210000Z --- NEAR 10.0S 48.8E
     MOVEMENT PAST SIX HOURS - 285 DEGREES AT 08 KTS
     POSITION ACCURATE TO WITHIN 030 NM
     POSITION BASED ON CENTER LOCATED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT
                            035 NM SOUTHEAST QUADRANT
                            035 NM SOUTHWEST QUADRANT
                            000 NM NORTHWEST QUADRANT
   REPEAT POSIT: 10.0S 48.8E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   211200Z --- 9.7S 47.3E
   MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 000 NM NORTHEAST QUADRANT
                            025 NM SOUTHEAST QUADRANT
                            025 NM SOUTHWEST QUADRANT
                            000 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 020 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            050 NM SOUTHWEST QUADRANT
                            020 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 275 DEG/ 08 KTS
    ---
   24 HRS, VALID AT:
   220000Z --- 9.5S 45.7E
   MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 000 NM NORTHEAST QUADRANT
                            020 NM SOUTHEAST QUADRANT
                            020 NM SOUTHWEST QUADRANT
                            000 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 000 NM NORTHEAST QUADRANT
                            025 NM SOUTHEAST QUADRANT
                            025 NM SOUTHWEST QUADRANT
                            000 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 020 NM NORTHEAST QUADRANT
                            050 NM SOUTHEAST QUADRANT
                            060 NM SOUTHWEST QUADRANT
                            020 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 280 DEG/ 05 KTS
    ---
   36 HRS, VALID AT:
   221200Z --- 9.3S 44.7E
   MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 000 NM NORTHEAST QUADRANT
                            020 NM SOUTHEAST QUADRANT
                            020 NM SOUTHWEST QUADRANT
                            000 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 000 NM NORTHEAST QUADRANT
                            025 NM SOUTHEAST QUADRANT
                            025 NM SOUTHWEST QUADRANT
                            000 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 020 NM NORTHEAST QUADRANT
                            060 NM SOUTHEAST QUADRANT
                            060 NM SOUTHWEST QUADRANT
                            020 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 285 DEG/ 04 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   230000Z --- 9.1S 43.9E
   MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 000 NM NORTHEAST QUADRANT
                            025 NM SOUTHEAST QUADRANT
                            025 NM SOUTHWEST QUADRANT
                            000 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 020 NM NORTHEAST QUADRANT
                            060 NM SOUTHEAST QUADRANT
                            060 NM SOUTHWEST QUADRANT
                            020 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 285 DEG/ 04 KTS
    ---
   72 HRS, VALID AT:
   240000Z --- 8.7S 42.3E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 020 NM NORTHEAST QUADRANT
                            060 NM SOUTHEAST QUADRANT
                            070 NM SOUTHWEST QUADRANT
                            030 NM NORTHWEST QUADRANT
   VECTOR TO 96 HR POSIT: 280 DEG/ 05 KTS
    ---
   LONG RANGE OUTLOOK:
    ---
   96 HRS, VALID AT:
   250000Z --- 8.4S 40.2E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 000 NM NORTHEAST QUADRANT
                            020 NM SOUTHEAST QUADRANT
                            020 NM SOUTHWEST QUADRANT
                            000 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 020 NM NORTHEAST QUADRANT
                            070 NM SOUTHEAST QUADRANT
                            070 NM SOUTHWEST QUADRANT
                            030 NM NORTHWEST QUADRANT
   VECTOR TO 120 HR POSIT: 270 DEG/ 06 KTS
    ---
   120 HRS, VALID AT:
   260000Z --- 8.5S 37.7E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
    ---
REMARKS:
210300Z POSITION NEAR 9.9S 48.4E.
21APR21. TROPICAL CYCLONE 29S (JOBO), LOCATED APPROXIMATELY 539
NM NORTH OF ANTANANARIVO, MADAGASCAR, HAS TRACKED WEST-NORTHWESTWARD
AT 08 KNOTS OVER THE PAST SIX HOURS. ENHANCED INFRARED SATELLITE
IMAGERY SHOWS A SMALL, RAPIDLY DEVELOPING CYCLONE, WITH A CURVED
BAND OF CONVECTION WITH CLOUD TOPS COLDER THAN -80C NEARLY
ENCIRCLING THE LOW-LEVEL CENTER. A 210052Z SSMIS 91GHZ MICROWAVE
IMAGE SHOWED A RING OF DEEP CONVECTION ABOUT 60 NM IN DIAMETER
WRAPPING AROUND 80% OF THE CIRCULATION, FORMING A WELL-DEFINED EYE-
LIKE FEATURE. THE INITIAL INTENSITY IS SET AT 45 KTS, PERHAPS
CONSERVATIVELY, BASED ON A 210230Z PGTW FIX OF 3.0. CONFIDENCE IN
THIS ESTIMATE IS LOW DUE TO THE RAPIDLY DEVELOPING NATURE OF THE
SYSTEM. THE LARGE-SCALE ENVIRONMENT HAS CONSISTED OF LIGHT-MODERATE
WESTERLY VERTICAL WIND SHEAR (VWS) OF 15-20 KTS FOR THE PAST 12
HOURS, BUT EXPANDING CIRRUS OUTFLOW IN THE WESTERN SEMICIRCLE
SUGGESTS THAT THIS SHEAR IS DECREASING. JOBO IS BEING STEERED WEST-
NORTHWESTWARD BY A BELT OF LOW-LEVEL EASTERLIES EQUATORWARD OF THE
SUBTROPICAL RIDGE. THIS MOTION WILL CARRY JOBO BENEATH AN UPPER-
LEVEL ANTICYCLONE SEEN IN WATER VAPOR SATELLITE IMAGERY OFFSHORE OF
TANZANIA DURING THE NEXT 12-18 HOURS, WHERE VWS IS EXPECTED TO
DECREASE TO 10-15 KTS. COMBINED WITH WARM SEA SURFACE TEMPERATURES
OF 29C, THIS ENVIRONMENT IS EXPECTED TO FAVOR RAPID INTENSIFICATION
IN THE NEAR TERM, TO AROUND 70 KTS AT 24 HOURS, SUPPORTED BY RECENT
HWRF MODEL FORECASTS THAT HAVE ACCURATELY DEPICTED THE COMPACT
NATURE OF THE VORTEX. IN 24-36 HOURS, AN UPPER-LEVEL TROUGH IN THE
SUBTROPICAL JET OVER MOZAMBIQUE WILL APPROACH JOBO FROM THE WEST,
INCREASING VWS BACK TO AROUND 20 KTS. THIS SHOULD ARREST THE
INTENSIFICATION TREND, AND THE SMALL CYCLONE, BEING PARTICULARLY
SUSCEPTIBLE TO MODERATE SHEAR, IS EXPECTED TO WEAKEN BETWEEN 36 AND
72 HOURS. SLOWING OF FORWARD MOTION IS ALSO EXPECTED AS LOW-LEVEL
EASTERLIES BECOME OFFSET BY THE UPPER-LEVEL WESTERLY FLOW. AFTER 72
HOURS, THE AFOREMENTIONED UPPER-LEVEL TROUGH MOVES AWAY TO THE
SOUTHEAST, POSSIBLY ALLOWING A PERIOD OF LIGHTER SHEAR ONCE AGAIN AS
JOBO APPROACHES THE TANZANIAN COASTLINE. THE FORECAST SHOWS THE
POSSIBILITY OF SOME REINTENSIFICATION BEFORE LANDFALL JUST AFTER 96
HOURS, FOLLOWED BY DISSIPATION INLAND. CONFIDENCE IN THE INTENSITY
FORECAST IS LOW, GIVEN THE SUSCEPTIBILITY OF COMPACT CYCLONES TO
QUICK UPS AND DOWNS IN INTENSITY. MAXIMUM SIGNIFICANT WAVE HEIGHT AT
210000Z IS 12 FEET. NEXT WARNINGS AT 211500Z AND 220300Z.
2. THIS CANCELS AND SUPERSEDES REF A (WTXS21 PGTW 200830).//
NNNN

dom

JTWC00Z升格29S

29S JOBO 210421 0000 10.0S 48.8E SHEM 40 1000

老農民版夜神月

JTWC雖18Z維持T2.0,30節
但目前DT,PT均已達2.5,可能將於明天白天升格

95S INVEST 210420 1800 10.3S 49.5E SHEM 30 1000

TPXS10 PGTW 201827

A. TROPICAL DISTURBANCE 95S (N OF MADAGASCAR)

B. 20/1800Z

C. 10.58S

D. 49.67E

E. FIVE/MET8

F. T2.0/2.0  STT: S0.0/03HRS

G. IR/EIR

H. REMARKS: 38A/PBO SBC/ANMTN. CNVCTN WRAPS .40 ON LOG10 SPIRAL
YIELDING A DT OF 2.5. MET YIELDS 2.0. PT YIELDS 2.5.  DBO MET.

I. ADDITIONAL POSITIONS:
   20/1534Z  10.40S  50.22E  SSMS


   YOUNG

老農民版夜神月

MFR首報上望熱帶氣旋，65KT

WTIO31 FMEE 201851
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN
INDIEN)

0.A NUMERO DU BULLETIN : 4/16/20202021
1.A TEMPETE TROPICALE MODEREE 16 (JOBO)

2.A POSITION A 1800 UTC LE 20/04/2021 :
DANS UN RAYON DE 30 MN AUTOUR DU POINT 10.3 S / 49.8 E
(DIX DEGRES TROIS SUD ET QUARANTE NEUF DEGRES HUIT EST)
DEPLACEMENT: OUEST 11 KT

3.A ANALYSE DE DVORAK: 2.5/2.5/D 1.0/24 H

4.A PRESSION AU CENTRE: 999 HPA
5.A VENT MAX (MOYEN/10 MN): 40 KT
RAYON DES VENTS MAXIMAUX (RVM): 24 KM

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
28 KT NE: 75 SE: 150 SO: 165 NO: 95
34 KT NE: 35 SE: 75 SO: 75 NO: 55

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: 1010 HPA / 200 KM
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: PROFONDE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 21/04/2021 06 UTC: 9.8 S / 48.1 E, VENT MAX= 050 KT, FORTE
TEMPETE TROPICALE
28 KT NE: 65 SE: 100 SO: 110 NO: 85
34 KT NE: 55 SE: 30 SO: 55 NO: 45
48 KT NE: 45 SE: 20 SO: 45 NO: 35

24H: 21/04/2021 18 UTC: 9.7 S / 46.8 E, VENT MAX= 065 KT, CYCLONE
TROPICAL
28 KT NE: 65 SE: 100 SO: 100 NO: 110
34 KT NE: 55 SE: 35 SO: 55 NO: 55
48 KT NE: 45 SE: 30 SO: 45 NO: 45
64 KT NE: 20 SE: 20 SO: 20 NO: 35

36H: 22/04/2021 06 UTC: 9.6 S / 45.6 E, VENT MAX= 065 KT, CYCLONE
TROPICAL
28 KT NE: 65 SE: 110 SO: 95 NO: 95
34 KT NE: 55 SE: 30 SO: 55 NO: 55
48 KT NE: 45 SE: 20 SO: 45 NO: 45
64 KT NE: 20 SE: 10 SO: 20 NO: 35

48H: 22/04/2021 18 UTC: 9.4 S / 44.5 E, VENT MAX= 050 KT, FORTE
TEMPETE TROPICALE
28 KT NE: 65 SE: 100 SO: 110 NO: 85
34 KT NE: 55 SE: 30 SO: 55 NO: 45
48 KT NE: 45 SE: 20 SO: 45 NO: 35

60H: 23/04/2021 06 UTC: 9.1 S / 43.7 E, VENT MAX= 040 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 45 SE: 85 SO: 85 NO: 85
34 KT NE: 35 SE: 10 SO: 20 NO: 35

72H: 23/04/2021 18 UTC: 9.0 S / 42.8 E, VENT MAX= 035 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 45 SE: 75 SO: 85 NO: 85
34 KT NE: 35 SE: 10 SO: 10 NO: 35

2.B TENDANCE ULTERIEURE:
96H: 24/04/2021 18 UTC: 8.6 S / 41.1 E, VENT MAX= 025 KT, DEPRESSION
SE COMBLANT

120H: 25/04/2021 18 UTC: 7.9 S / 39.4 E, VENT MAX= 020 KT, DEPRESSION
SUR TERRE

2.C COMMENTAIRES:
T=CI=2.5+

AU COURS DES 6 DERNIERES HEURES, LA CONVECTION S'EST NETTEMENT
INTENSIFIEE, AVEC DE PUISSANTS BURSTS CONVECTIFS A L'APLOMB DU CENTRE
DE SURFACE (CDO AVEC SOMMETS NUAGEUX < -80C). LES RECENTES PASSES
MICRO-ONDES (SSMIS 1532Z) MONTRENT UN GAIN EN ORGANISATION DU
SYSTEME. AVEC DES VENTS MESURES A 30/35 KT DES CE MATIN ET EN TENANT
COMPTE DE L'INTENSIFICATION EN COURS DU SYSTEME, LES VENTS SONT
ESTIMES A 40 KT A 1800Z. LE STADE DE TEMPETE TROPICALE MODEREE EST
DONC CONFIRME, AVEC UN SYSTEME BAPTISE "JOBO" DEPUIS 1500Z.

LA TRAJECTOIRE VERS L'OUEST A OUEST-NORD-OUEST SE CONFIRME, AVEC UN
ASSEZ BON ACCORD ENTRE MODELES POUR LES 48 PROCHAINES HEURES. LE
SYSTEME SE DEPLACE SUR LA FACE NORD DE LA DORSALE SUBTROPICALE DE
BASSE TROPOSPHERE ET DEVRAIT PASSER A PROXIMITE DU SUD DES ILES
EXTERIEURES DES SEYCHELLES EN JOURNEE DE MERCREDI ET NUIT SUIVANTE
TOUT EN RALENTISSANT PROGRESSIVEMENT. A PARTIR DE JEUDI,
L'INCERTITUDE SUR LA TRAJECTOIRE AUGMENTE AVEC DES FLUX DIRECTEURS
DEVENANT PLUS FAIBLES ET LA TRAJECTOIRE DEPENDANT AUSSI DE
L'INTENSITE QUE LE SYSTEME AURA A CE MOMENT-LA. LA PRESENTE PREVISION
SE BASE SUR UN SCENARIO MEDIAN MAIS RESTERA A CONFIRMER.

LES CONDITIONS ENVIRONNEMENTALES RESTENT RELATIVEMENT FAVORABLES AU
DEVELOPPEMENT A COURTE ECHEANCE JUSQU'A LA NUIT DE MERCREDI A JEUDI :
EN BASSES COUCHES, LA POUSSEE D'ALIZE RENFORCEE PAR L'ACCELERATION
LIEE AU CONTOURNEMENT NORD DE MADAGASCAR AUGMENTE LA CONVERGENCE COTE
POLAIRE. PENDANT CE TEMPS LA CONVERGENCE COTE EQUATORIAL RESTE
TOUTEFOIS FAIBLE A TRES FAIBLE, CE QUI APPORTE DE L'INCERTITUDE SUR
LA CONSOLIDATION PLUS OU MOINS EFFICACE DU COEUR DEPRESSIONNAIRE. EN
ALTITUDE, LE CISAILLEMENT PROFOND DE SUD-OUEST EST EN BAISSE ET NE
SEMBLE PAS TROP AFFECTER LE DEVELOPPEMENT DU SYSTEME A COURT TERME,
DANS UN ENVIRONNEMENT RESTANT SUFFISAMMENT HUMIDE ET SOUS UNE
DIVERGENCE DE HAUTE TROPOSPHERE ASSEZ BONNE. MERCREDI SOIR, UNE
AUGMENTATION DE LA DIVERGENCE EN MARGE D'UN TALWEG SUBTROPICAL
CIRCULANT PLUS AU SUD POURRAIT PERMETTRE AU SYSTEME D'ATTEINDRE LE
STADE DE CYCLONE TROPICAL. MAIS ENSUITE, A PARTIR DE JEUDI, UN
CISAILLEMENT DE NORD-OUEST DEVRAIT SE METTRE EN PLACE EN MARGE D'UN
TALWEG PASSANT SUR LE SUD DE MADAGASCAR, ET DEVRAIT DESTRUCTURER LE
COEUR CONVECTIF EN Y ADVECTANT DE L'AIR SEC. CELA DEVRAIT CONDUIRE A
L'AFFAIBLISSEMENT DU SYSTEME EN DEUXIEME PARTIE DE SEMAINE.
LA PETITE TAILLE DU COEUR DEPRESSIONNAIRE LE RENDANT TRES REACTIF A
SON ENVIRONNEMENT INDUIT UNE INCERTITUDE PLUS FORTE QUE LA MOYENNE
SUR LA PRESENTE PREVISION D'INTENSITE.

IMPACTS POSSIBLES ATTENDUS SUR LES ILES EXTERIEURES DES SEYCHELLES
(ASTOVE, COSMOLEDO, ALDABRA) :
-PLUIES TRES INTENSES POUVANT EXCEDER LES 150 A 200 MM EN 24H.
-VENTS FORTS (DEPENDANT DE LA TRAJECTOIRE EXACTE DU PHENOMENE): DES
CONDITIONS CYCLONIQUES (RAFALES SUPERIEURES A 150 KM/H) NE SONT PAS A
EXCLURE
-MER DANGEREUSE: VAGUES DEPASSANT LOCALEMENT LES 5 METRES.=

老農民版夜神月

MFR率先升格中度熱帶風暴並命名Jobo

WTIO22 FMEE 201813
SECURITE
GALE WARNING FOR METAREA VII AND METAREA VIII (S)
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 20/04/2021
AT 1800 UTC.
WARNING NUMBER: 004/16 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

GALE WARNING
BEGINNING OF VALIDITY: TUESDAY 20/04/2021 AT 1800 UTC.

PHENOMENON: MODERATE TROPICAL STORM 16 (JOBO) 999 HPA
POSITION: WITHIN 30 NM RADIUS OF POINT 10.3 S / 49.8 E
(TEN    DECIMAL THREE   DEGREES SOUTH AND
FORTY NINE    DECIMAL EIGHT   DEGREES EAST) AT 1800 UTC
MOVEMENT: WEST 11 KT

THREAT AREAS:
SQUALLY WEATHER WITHIN A 100 NM RADIUS FROM THE CENTER, EXTENDING UP
TO 200 NM IN THE SOUTHERN SEMI-CIRCLE.


GALE FORCE WINDS 35/40 KT AND VERY ROUGH TO HIGH SEAS WITHIN A 20 NM
RADIUS FROM THE CENTRE, EXTENDING UP TO 30 NM IN THE NORTH-WESTERN
QUADRANT AND UP TO 40 NM IN THE SOUTHERN SEMI-CIRCLE.
NEAR GALE FORCE WINDS 30 KT AND ROUGH TO VERY ROUGH SEAS WITHIN A 40
NM RADIUS FROM THE CENTRE, EXTENDING UP TO 50 NM IN THE NORTH-WESTERN
QUADRANT, UP TO 80 NM IN THE SOUTH-EASTERN QUADRANT AND UP TO 90 NM
IN THE SOUTH-WESTERN QUADRANT.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2021/04/21 AT 06 UTC:
9.8 S / 48.1 E, MAX WIND = 50 KT, SEVERE TROPICAL STORM
28 KT NE: 35 NM SE: 55 NM SW: 60 NM NW: 45 NM
34 KT NE: 30 NM SE: 15 NM SW: 30 NM NW: 25 NM
48 KT NE: 25 NM SE: 10 NM SW: 25 NM NW: 20 NM

24H, VALID 2021/04/21 AT 18 UTC:
9.7 S / 46.8 E, MAX WIND = 65 KT, TROPICAL CYCLONE
28 KT NE: 35 NM SE: 55 NM SW: 55 NM NW: 60 NM
34 KT NE: 30 NM SE: 20 NM SW: 30 NM NW: 30 NM
48 KT NE: 25 NM SE: 15 NM SW: 25 NM NW: 25 NM
64 KT NE: 10 NM SE: 10 NM SW: 10 NM NW: 20 NM

OTHER INFORMATION:
NIL.=

dom

JTWC0830Z發佈TCFA

WTXS21 PGTW 200830
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 95S)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
105NM EITHER SIDE OF A LINE FROM 10.9S 52.8E TO 9.6S 47.0E
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 28 TO 33 KNOTS. METSAT
IMAGERY AT 200600Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 10.8S 52.4E. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 14
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 95S) PREVIOUSLY LOCATED
NEAR 11.1S 53.8E IS NOW LOCATED NEAR 10.8S 52.4E, APPROXIMATELY 634
NM NORTH-NORTHWEST OF MAURITIUS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY AND A 200256Z SSMIS 91GHZ MICROWAVE IMAGE REVEAL FORMATIVE
BANDING WITH CYCLING CONVECTION TO THE NORTHEAST AND SOUTH OF THE
LOW LEVEL CIRCULATION CENTER (LLCC). A 200623Z ASCAT-B BULLSEYE PASS
SHOWS A WELL DEFINED LLCC AND AN ASYMMETRIC WIND FIELD, WITH 25-30KT
WINDS AND A RELATIVELY SMALLER AREA OF 30-35KT WINDS IN THE SOUTHERN
SEMICIRCLE. THE AFOREMENTIONED DATA LEND HIGH CONFIDENCE TO THE
ANALYSIS POSITION. INVEST 95S IS IN AN ENVIRONMENT CONDUCIVE FOR
INTENSIFICATION, WITH MODERATE EQUATORWARD AND EASTWARD OUTFLOW
ALOFT, LOW TO MODERATE (15-20KTS) VERTICAL WIND SHEAR, AND WARM (29-
30C) SEA SURFACE TEMPERATURES. GLOBAL MODELS ARE IN GENERAL
AGREEMENT THAT INVEST 95S WILL TRACK WESTWARD AS IT INTENSIFIES AND
PASSES NORTH OF MADAGASCAR OVER THE NEXT 24 HOURS. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 28 TO 33 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 998 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
210830Z.//
NNNN

dom

MFR09Z升格熱帶低壓

WTIO30 FMEE 200640
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 2/16/20202021
1.A TROPICAL DEPRESSION 16

2.A POSITION 2021/04/20 AT 0600 UTC:
WITHIN 20 NM RADIUS OF POINT 11.0 S / 52.4 E
(ELEVEN    DECIMAL ZERO   DEGREES SOUTH AND
FIFTY TWO    DECIMAL FOUR   DEGREES EAST)
MOVEMENT: WEST 12 KT

3.A DVORAK ANALYSIS: 2.5/2.5/D 1.0/24 H

4.A CENTRAL PRESSURE: 1003 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 30 KT
RADIUS OF MAXIMUM WINDS (RMW): 37 KM

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 0 SE: 95 SW: 0 NW: 0

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1010 HPA / 200 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM

1.B FORECASTS (WINDS RADII IN KM):
12H: 2021/04/20 18 UTC: 10.6 S / 50.1 E, VENT MAX= 035 KT, MODERATE
TROPICAL STORM
28 KT NE: 0 SE: 370 SW: 315 NW: 0
34 KT NE: 0 SE: 220 SW: 185 NW: 0

24H: 2021/04/21 06 UTC: 9.9 S / 48.4 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 75 SE: 370 SW: 315 NW: 185
34 KT NE: 0 SE: 220 SW: 185 NW: 0

36H: 2021/04/21 18 UTC: 9.8 S / 47.1 E, VENT MAX= 045 KT, MODERATE
TROPICAL STORM
28 KT NE: 75 SE: 370 SW: 315 NW: 185
34 KT NE: 75 SE: 220 SW: 185 NW: 75

48H: 2021/04/22 06 UTC: 9.7 S / 45.9 E, VENT MAX= 050 KT, SEVERE
TROPICAL STORM
28 KT NE: 75 SE: 370 SW: 315 NW: 185
34 KT NE: 110 SE: 220 SW: 185 NW: 110
48 KT NE: 20 SE: 35 SW: 35 NW: 20

60H: 2021/04/22 18 UTC: 9.6 S / 45.1 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 75 SE: 370 SW: 315 NW: 185
34 KT NE: 75 SE: 220 SW: 185 NW: 75

72H: 2021/04/23 06 UTC: 9.5 S / 44.7 E, VENT MAX= 035 KT, MODERATE
TROPICAL STORM
28 KT NE: 0 SE: 370 SW: 315 NW: 0
34 KT NE: 0 SE: 220 SW: 185 NW: 0

2.B LONGER-RANGE OUTLOOK:
96H: 2021/04/24 06 UTC: 9.7 S / 43.3 E, VENT MAX= 025 KT, FILLING UP

120H: 2021/04/25 06 UTC: 8.9 S / 40.1 E, VENT MAX= 020 KT, FILLING UP

2.C ADDITIONAL INFORMATION:
T=CI=2.5

THE CIRCULATION THAT HAS BEEN MONITORED SINCE LAST WEEK VIA THE
RSMC'S ITCZ BULLETINS, WHILE CIRCULATING NEAR THE CHAGOS, HAS
EXPERIENCED A TEDIOUS DEVELOPMENT DURING ITS WESTWARD TRACK, IN A TOO
DRY ENVIRONMENT LINKED TO THE DRY PHASE OF THE MJO AND WITH A LACK OF
EQUATORWARD CONVERGENCE. HOWEVER, SINCE YESTERDAY SUNDAY AND MONDAY,
AND ESPECIALLY THE LAST NIGHT, IT SHOWS SIGNS OF BETTER ORGANIZATION,
AS IT TRACKS TOWARDS THE NORTH OF MADAGASCAR THIS THUESDAY.
THE DEEP CONVECTION OF MODERATE INTENSITY IS STILL QUITE FLUCTUATING,
AND MAINLY PRESENT IN THE NORTH-WEST SEMICIRCLE.
THE LAST ASCAT SWATHS OF THE LAST NIGHT INDICATE WINDS OF 30 KT, VERY
LOCALLY 35KT, IN THE SOUTHEASTERN SEMICIRCLE OF THE SYSTEM, UP FROM
THE PREVIOUS DAYS, BUT WITH A STRUCTURE THAT REMAINS ASYMMETRIC
(SIGNIFICANTLY WEAKER WINDS IN THE NORTHWESTERN SEMICIRCLE). THE
SSMIS MICROWAVE PASS OF 0103Z SHOWS THE BEGINNING OF AN ORGANIZATION
OF THE SYSTEM, WITH THE BEGINNINGS OF A CURVED BAND IN THE NORTHERN
SEMICIRCLE OF THE CIRCULATION.

THERE IS A GOOD AGREEMENT BETWEEN MODELS ABOUT THE SYSTEM'S TRACK
UNTIL WEDNESDAY, WITH A WESTWARD MOVEMENT ON THE NORTHERN SIDE OF THE
LOW TROPOSPHERIC SUBTROPICAL RIDGE, TRACKING IMMEDIATELY SOUTH OF THE
FARQUHAR ATOLL AND OFF NORTHERN MADAGASCAR. FROM WEDNESDAY AND
THURSDAY, WHEN THE SYSTEM WILL REACH THE NORTH OF THE MOZAMBIQUE
CHANNEL AND OFF THE COMOROS, THE STEERING FLOWS BECOME WEAKER AND THE
TRAJECTORY IS MORE UNCERTAIN , MARKING A SLOWDOWN, EVEN A LOOP ON
SOME MODELS IN THE NORTH OF THE COMOROS. IN CONSEQUENCES, THE MORE OR
LESS IMPORTANT INFLUENCE ON THE NORTH OF THE COMOROS ARCHIPELAGO
REMAINS TO BE SPECIFIED.

ENVIRONMENTAL CONDITIONS ARE RELATIVELY FAVORABLE TO SHORT TERM
DEVELOPMENT : IN THE LOW LAYERS, A TRADEWINDS SURGE IS ONGOING,
REINFORCED TOMORROW BY THE ACCELERATION RELATED TO THE BYPASS OF THE
NORTHERN TIP OF MADAGASCAR, WHICH SHOULD INCREASE THE POLEWARD LOW
LEVEL CONVERGENCE. HOWEVER, DURING THIS TIME, THE EQUATORWARD
CONVERGENCE REMAINS WEAK TO VERY WEAK, WHICH BRINGS UNCERTAINTY ON
THE MORE OR LESS EFFICIENT CONSOLIDATION OF THE LOW'S INNER CORE.
ALOFT, DEEP SHEAR IS WEAK AND SHOULD REMAIN SO FOR THE NEXT FEW DAYS
(AROUND 10 KT OR LESS), AND NO INTRUSION OF DRY AIR IN THE
MID-TROPOSPHERE SHOULD INTERFERE WITH CONVECTION NEAR THE CORE OF THE
SYSTEM UNTIL WEDNESDAY. UPPER-TROPOSPHERIC DIVERGENCE IS QUITE GOOD
WITH A TEMPORARY LIGHT EQUATORWARD OUTFLOW CHANNEL IN THE SHORT RUN
ON THUESDAY, THEN, FROM MID-WEEK, AN INCREASE OF UPPER DIVERGENCE ON
THE EDGE OF A SUBTROPICAL TROUGH CIRCULATING FURTHER SOUTH. ON THE
OTHER HAND, THE OCEANIC POTENTIAL IS PRESENT WITH SST AROUND 28-29C
AND A GRADUAL INCREASE OF THE DEPTH OF THE ISO-26C, BECOMING HIGHER
IN THE NORTH OF THE MOZAMBIQUE CHANNEL. THUS, CONDITIONS SEEM TO BE
GATHERED FOR MODERATE INTENSIFICATION UNTIL WEDNESDAY, PROBABLY UNTIL
THE STAGE OF A MODERATE TROPICAL STORM OR EVEN SEVERE TROPICAL STORM.
FROM THURSDAY, THE INCREASE OF THE NORTH TO NORTH-WESTERLY SHEAR
ALONG A TROUGH PASSING OVER THE SOUTH OF MADAGASCAR SHOULD TILT THE
CONVECTIVE CORE AND WEAKEN IT BY ADVECTING DRY AIR. THIS SHOULD LEAD
TO THE WEAKENING OF THE SYSTEM IN THE SECOND PART OF THE WEEK.
THE SMALL SIZE OF THE LOW'S CORE, MAKING IT VERY REACTIVE TO ITS
ENVIRONMENT, INDUCES A HIGHER THAN AVERAGE UNCERTAINTY ON THE PRESENT
INTENSITY FORECAST.

dom

JTWC將評級提升至Medium

(1) THE AREA OF CONVECTION (INVEST 95S) PREVIOUSLY LOCATED
NEAR 11.4S 55.7E IS NOW LOCATED NEAR 11.1S 53.9E, APPROXIMATELY 580
NM NORTH-NORTHWEST OF MAURITIUS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY AND A 192137Z AMSR2 89GHZ MICROWAVE IMAGE DEPICT A
CONSOLIDATING LOW LEVEL CIRCULATION CENTER WITH FRAGMENTED FORMATIVE
BANDING AND FLARING CONVECTION. A 191831Z ASCAT-C PARTIAL PASS SHOWS
A DEFINED CIRCULATION WITH 25-30KT WINDS MOSTLY IN THE SOUTHERN
SEMICIRCLE AND LESSER WINDS ELSEWHERE. ENVIRONMENTAL ANALYSIS
INDICATES A FAVORABLE ENVIRONMENT FOR DEVELOPMENT CHARACTERIZED BY
LOW TO MODERATE (15-20KTS) VERTICAL WIND SHEAR, MODERATE OUTFLOW
ALOFT, AND WARM (29-30C) SEA SURFACE TEMPERATURES. GLOBAL MODELS ARE
IN GENERAL AGREEMENT THAT INVEST 95S WILL TRACK WESTWARD WITH SOME
INTENSIFICATION NEAR NORTHERN MADAGASCAR IN 1-2 DAYS. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1004 MB. THE POTENTIAL FOR
THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS UPGRADED TO MEDIUM.