SIO: GUAMBE - Post-Tropical

[Nancy Smar]

93S INVEST 210210 1200 22.5S 40.0E SHEM 15 1010

[Nancy Smar]

Le centre du minimum dépressionnaire qui évoluait sur terre Mozambicaine durant les deux derniers jours est ressortie en mer ce matin au niveau de la ville d’Inhassoro (Mozambique). Il est désormais classé au stade initial de Perturbation Tropicale. Les données satellites disponibles ainsi que les observations de Mozambique permet d’estimer le vent moyen autour de son centre à 46 Km/h. Son centre est localisé à environ 890 Km à l’Ouest de Morombe. Le flux de mousson reste actif sur la grande partie du Canal et s’étend jusqu’au littoral Ouest de Madagascar.

B. Perspective dans les cinq prochains jours
Les tendances des données analysées permettent d’anticiper une condition atmosphérique et océanique favorable (eau de mer assez chaude) au maintien et au développement du futur GUAMBE. A la lumière de l’évolution récente, il peut grimper au stade d’une Tempête Tropicale dans les prochaines 30 heures.

En termes de Trajectoire, un déplacement vers le Nord-Nord-Est est prévue jusqu’à demain suivi d’une boucle vers le Sud et laissant normalement Madagascar en dehors de danger potentiel.

[Nancy Smar]

WTIO30 FMEE 161253
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 2/11/20202021
1.A TROPICAL DISTURBANCE 11

2.A POSITION 2021/02/16 AT 1200 UTC:
WITHIN 20 NM RADIUS OF POINT 20.8 S / 36.0 E
(TWENTY DECIMAL EIGHT DEGREES SOUTH AND
THIRTY SIX DECIMAL ZERO DEGREES EAST)
MOVEMENT: NORTH-EAST 7 KT

3.A DVORAK ANALYSIS: 1.5/1.5/S 0.0/6 H

4.A CENTRAL PRESSURE: 995 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 25 KT
RADIUS OF MAXIMUM WINDS (RMW): NIL

6.A EXTENSION OF WIND BY QUADRANTS (KM):
NIL

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1003 HPA / 1100 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM

1.B FORECASTS (WINDS RADII IN KM):
12H: 2021/02/17 00 UTC: 20.0 S / 36.3 E, VENT MAX= 030 KT, TROPICAL
DEPRESSION
28 KT NE: 75 SE: 100 SW: 75 NW: 85

24H: 2021/02/17 12 UTC: 20.5 S / 37.1 E, VENT MAX= 035 KT, MODERATE
TROPICAL STORM
28 KT NE: 130 SE: 165 SW: 85 NW: 120
34 KT NE: 100 SE: 85 SW: 10 NW: 85

36H: 2021/02/18 00 UTC: 21.7 S / 37.4 E, VENT MAX= 035 KT, MODERATE
TROPICAL STORM
28 KT NE: 110 SE: 150 SW: 85 NW: 120
34 KT NE: 85 SE: 65 SW: 10 NW: 85

48H: 2021/02/18 12 UTC: 22.6 S / 37.2 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 220 SE: 250 SW: 95 NW: 130
34 KT NE: 140 SE: 150 SW: 30 NW: 110

60H: 2021/02/19 00 UTC: 23.3 S / 37.0 E, VENT MAX= 045 KT, MODERATE
TROPICAL STORM
28 KT NE: 215 SE: 100 SW: 75 NW: 65
34 KT NE: 150 SE: 30 SW: 20 NW: 55

72H: 2021/02/19 12 UTC: 23.9 S / 36.5 E, VENT MAX= 055 KT, SEVERE
TROPICAL STORM
28 KT NE: 150 SE: 270 SW: 315 NW: 85
34 KT NE: 100 SE: 110 SW: 165 NW: 45
48 KT NE: 35 SE: 55 SW: 55 NW: 35

2.B LONGER-RANGE OUTLOOK:
96H: 2021/02/20 12 UTC: 25.4 S / 35.9 E, VENT MAX= 070 KT, TROPICAL
CYCLONE
28 KT NE: 260 SE: 215 SW: 100 NW: 130
34 KT NE: 140 SE: 120 SW: 65 NW: 100
48 KT NE: 65 SE: 45 SW: 55 NW: 45
64 KT NE: 55 SE: 35 SW: 35 NW: 35

120H: 2021/02/21 12 UTC: 28.2 S / 37.5 E, VENT MAX= 080 KT, TROPICAL
CYCLONE
28 KT NE: 285 SE: 195 SW: 85 NW: 140
34 KT NE: 130 SE: 100 SW: 75 NW: 110
48 KT NE: 80 SE: 60 SW: 60 NW: 70
64 KT NE: 70 SE: 60 SW: 60 NW: 60

2.C ADDITIONAL INFORMATION:
T=CI=1.5

THIS AFTERNOON, CONVECTION HAS INTENSIFIED AROUND THE LOW PRESSURE
AREA, WITH THE LOW LEVEL CIRCULATION CENTER LOCATED TO THE SOUTH-EAST
OF THE MAXIMUM OF CONVECTION. WITHOUT ANY HELPFUL MICROWAVE IMAGERY,
IT IS DIFFICULT TO ASSESS HOW MUCH THE LOW LEVEL CIRCULATION HAS
TIGHTENED. THE SYSTEM'S INTENSITY IS KEPT AT 25KT, IN AGREEMENT WITH
THE LATEST ASCAT PASS. THE VERY LOW ENVIRONMENTAL PRESSURES MAKE THE
ESTIMATED CENTRAL PRESSURE MUCH LOWER THAN THE PRESSURE USUALLY
EXPECTED FOR A TROPICAL DISTURBANCE.

THE SYSTEM MOVES NORTHEASTWARD IN THE MOZAMBIQUE CHANNEL AT THE
BEGINNING OF ITS LIFE CYCLE, UNDER THE COMBINED INFLUENCE OF A
LOW-LEVEL SOUTHWARD SURGE ON THE EDGE OF THE SOUTH AFRICAN SURFACE
HIGH AND THE WESTERLY FLOW ESTABLISHED AT ABOUT 700HPA ON THE EDGE OF
THE NEAR-EQUATORIAL RIDGE. THE PRESENCE OF A SECONDARY MINIMUM TO THE
SOUTHEAST OF THE SYSTEM COULD TEMPORARILY INFLUENCE ITS TRACK UNTIL
THURSDAY. FROM THURSDAY, A SUBTROPICAL RIDGE REBUILDS TOWARDS
MADAGASCAR, STEERING THE TRACK MORE SOUTHWARD ON ITS WESTERN SIDE.
WITH THE PERSISTENCE OF A RIDGE OVER SOUTHERN AFRICA, THE SYSTEM MAY
EXPERIENCE CONTRADICTORY INFLUENCES IN TERMS OF STEERING FLOW, WHICH
COULD RESULT IN A RATHER SLOW MOVEMENT. FROM FRIDAY, THE RIDGE ALONG
THE INDIAN OCEAN AND MADAGASCAR COAST STRENGTHENS SOUTHEAST OF THE
SYSTEM, WHICH COULD GIVE A SOUTHWEST COMPONENT TO THE TRACK. AROUND
THIS MEDIAN SCENARIO, GUIDANCE REMAINS VERY SCATTERED. THE
UNCERTAINTY ABOUT THIS FORECAST IS THUS QUITE IMPORTANT. IN
PARTICULAR, LANDFALL ON THE MOZAMBICAN COAST CANNOT BE RULED OUT IN
THE NEXT FEW DAYS.

THE SYSTEM IS CURRENTLY IN LOW SHEAR ENVIRONMENT UNDER THE UPPER
TROPOSPHERE RIDGE. IT IS SURROUNDED BY MOIST AIR AT ALL LEVELS
ALTHOUGH SOME DRY AIR ADVECTION MAY OCCUR ON THE WESTERN SIDE OF
SYSTEM IN THE NEXT 48 HOURS. LOW-LEVEL CONVERGENCE IS GOOD ON ITS
POLAR SIDE DUE TO THE SOUTHERLY WIND SURGE THIS TUESDAY, BUT IS STILL
POOR ON THE NORTHEAST SIDE OF THE SYSTEM, IN THE MOZAMBIQUE CHANNEL,
WHICH WILL KEEP THE CIRCULATION ELONGATED UNTIL WEDNESDAY. FROM
THURSDAY ONWARDS, GUIDANCE SUGGEST A BETTER LOW LEVEL CONVERGENCE IN
AN ENVIRONMENT THAT IS STILL FAVORABLE, WHICH SHOULD HELP ORGANIZE A
MORE COMPACT CORE. FROM THEN ON, STEADIER INTENSIFICATION BECOMES
POSSIBLE. HOWEVER, FROM FRIDAY EVENING SOME EASTERLY SHEAR ASSOCIATED
WITH MID-TROPOSPHERIC DRY AIR ADVECTION COULD LIMIT INTENSIFICATION,
AS DEPICTED BY THE LAST GFS RUN. BUT THIS SCENARIO ISN'T WIDESPREAD
IN THE AVAILABLE GUIDANCE.=

[Nancy Smar]

WTXS21 PGTW 160300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 93S)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 21.9S 34.1E TO 20.8S 37.6E
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 20 TO 25 KNOTS. METSAT
IMAGERY AT 160000Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 21.6S 35.1E. THE SYSTEM IS MOVING EAST-NORTHEASTWARD AT 11
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 93S) PREVIOUSLY LOCATED
NEAR 22.3S 33.8E IS NOW LOCATED NEAR 21.6S 35.1E, APPROXIMATELY 136
NM NORTH OF MAXIXE, MOZAMBIQUE. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY, SUPPORTED BY A 152224Z AMSR2 GW1 89GHZ PARTIAL MICROWAVE
IMAGE, DEPICTS PERSISTENT DEEP CONVECTION OVERHEAD THE LOW LEVEL
CIRCULATION CENTER (LLCC) GRADUALLY MOVING NORTHEASTWARD OUT TO SEA
WITH A LARGE AREA OF UNSTRUCTURED, FLARING DEEP CONVECTION OFFSET TO
THE NORTHWEST. 93S IS CURRENTLY IN A MARGINAL ENVIRONMENT WITH LOW
(10 TO 15 KNOTS) VERTICAL WIND SHEAR AND NEAR RADIAL UPPER LEVEL
OUTFLOW BEING OFFSET BY CONTINUED LAND INTERACTION; HOWEVER, ONCE
THE SYSTEM MOVES OVER OPEN WATER, IT WILL HAVE ACCESS TO WARM (29 TO
30 CELSIUS) SEA SURFACE TEMPERATURES. GLOBAL MODELS ARE IN GOOD
AGREEMENT THAT 93S WILL TRACK GENERALLY NORTHEASTWARD AS IT MOVES
OVER WATER AND BEGINS TO INTENSIFY, BEFORE IT MAKES A SOUTHWARD
TURN. 93S IS EXPECTED TO REACH WARNING THRESHOLD WITHIN 36 HOURS.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 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 HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
170300Z.//
NNNN

[aspen]

Guambe is forming a pinhole eye, but already an outer eyewall is developing. Let’s see how long the pinhole lasts before it transitions to a large-eye system like the HWRF has continuously forecast.

[Homie J]

Eye looks pretty good now

[cycloneye]

 https://twitter.com/jnmet/status/1363129081399816195