SIO: CALVINIA - Moderate Tropical Storm

[Nancy Smar]

95S INVEST 191212 0000 4.0S 77.5E SHEM 15 1010

96S.INVEST.15kts.1007mb.6S.76E.

[Nancy Smar]

SH, 95, 2019121206, , BEST, 0, 47S, 769E, 15, 1009, DB, 0, , 0, 0, 0, 0, 0, 0, 0, 0, 0, , 0, , 0, 0, INVEST, ,
SH, 95, 2019121212, , BEST, 0, 60S, 760E, 15, 1006, DB, 0, , 0, 0, 0, 0, 1007, 85, 0, 0, 0, , 0, , 0, 0, INVEST, ,

SH, 96, 2019121206, , BEST, 0, 47S, 769E, 15, 1009, DB, 0, , 0, 0, 0, 0, 0, 0, 0, 0, 0, , 0, , 0, 0, INVEST, ,
SH, 96, 2019121212, , BEST, 0, 60S, 760E, 15, 1006, DB, 0, , 0, 0, 0, 0, 1007, 85, 0, 0, 0, , 0, , 0, 0, INVEST, ,

[TorSkk]

TROPICAL WEATHER DISCUSSION:

A large clockwise circulation is located within the near equatorial area East of 65E. This large-scale
structure corresponds to the signature of an active Mixed Rossby-Gravity wave. It should be noted
also that a Kelvin wave is also forecast to pass over the basin over the next few days.
This morning ASCAT swath only shows a very wide clockwise circulation, with no well defined
center North of the Chagos archipelago. The western semi-circle is occupied by mid-level dry air
but convection is very active elsewhere. Over the next days, under the influence of the equatorial
wave activity, environmental conditions should gradually become more conducive for cyclogenesis,
with especially a good low-level convergence. However, from Monday, a light North to
Northwesterly upper shear constraint associated with mid-tropospheric dry air could slow down, or
even impede, the cyclogenesis process.
Cyclogenesis remains suggested by the available guidance, however not by all models and all runs.
The ensemble prediction still suggest a rather low cyclogenesis risk for the next 5 days.

Over the next 5 days, the risk of formation of a moderate tropical storm over the center of the
basin becomes low on Tuesday.

[1900hurricane]

What is up with the JTWC invest double tags lately? This is the second time they've done this within the last week or so. Based on NRL, it looks like they finally settled on 96S.

[wxman57]

Appears to be at least a TD (good ScatSat and ASCAT hits today confirm well-defined LLC). Convection has increased since the scatterometer hits. Max winds may be 35 kts now. La Reunion says it's an "almost closed low" (I'd beg to differ) with no chance of development.

[wxman57]

ASCAT confirmed that this system is now a TS, but Meteo France continues to ignore it. Not even an updated outlook since Monday morning. Maybe no one is working there during the holidays?

[aspen]

ASCAT confirmed that this system is now a TS, but Meteo France continues to ignore it. Not even an updated outlook since Monday morning. Maybe no one is working there during the holidays?

I don’t think anyone in the eastern hemisphere has been working these last two months

[1900hurricane]

It's still out there. I don't think I've ever seen JTWC so determined to not classify a system.

[Hayabusa]

WTXS23 PGTW 290300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 96S) REISSUED//
REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/281451ZDEC19//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
085 NM EITHER SIDE OF A LINE FROM 13.1S 60.0E TO 16.6S 60.1E
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 25 TO 30 KNOTS. METSAT
IMAGERY AT 290000Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 17.2S 60.7E. THE SYSTEM IS MOVING SOUTHWARD AT 13 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 96S) PREVIOUSLY LOCATED
NEAR 15.3S 60.5E IS NOW LOCATED NEAR 17.2S 60.7E, APPROXIMATELY 268
NM NORTHEAST OF MAURITIUS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY AND A 290040Z SSMIS 91GHZ MICROWAVE IMAGE DEPICT A
CONSOLIDATING LOW LEVEL CIRCULATION WITH DEEP, FLARING CONVECTION
WRAPPING INTO THE CIRCULATION. 96S IS CURRENTLY IN A FAVORABLE
ENVIRONMENT WITH EXCELLENT POLEWARD OUTFLOW, LOW (<15 KNOT) VERTICAL
WIND SHEAR, AND WARM (29 TO 30 CELSIUS) SEA SURFACE TEMPERATURES.
GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 96S WILL TRACK SOUTHWARD
WHILE CONTINUING TO INTENSIFY. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1000 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS HIGH.
THIS SUPERSEDES REF A (WTXS21 PGTW 281500).
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
300300Z.
//
NNNN

[wxman57]

The original 96S moved across northern Madagascar and into northern Mozambique two ago. You can still see its circulation on the sat pic below. This system is energy of another system that was east of 96S. Anyway, Meteo France upgraded it to a depression now.

[Nancy Smar]

FKIO20 FMEE 291213

TC ADVISORY

DTG: 20191229/1213Z

TCAC: REUNION

TC: CALVINIA

ADVISORY NR: 2019/01

OBS PSN: 29/1200Z S1924 E06014

CB: WI 600NM OF TC CENTRE TOP FL500

MOV: SSW 10KT

C: 993HPA

MAX WIND: 35KT

FCST PSN +6 HR: 29/1800Z S2001 E05943

FCST MAX WIND +6 HR: 38KT

FCST PSN +12 HR: 30/0000Z S2033 E05915

FCST MAX WIND +12 HR: 40KT

FCST PSN +18 HR: 30/0600Z S2055 E05852

FCST MAX WIND +18 HR: 40KT

FCST PSN +24 HR: 30/1200Z S2109 E05842

FCST MAX WIND +24 HR: 40KT

RMK: NIL

NXT MSG: 20191229/1800Z=