SIO: Emang - Tropical Depression

[supercane4867]

15kts 1010mb 4S 87.8E

[Grifforzer]

At the extreme East of the basin : morning ASCAT data suggest an 10-15 knots, elongated low level circulation, located near 4.5S 88.5E, within a convective active area. Mean sea level pressure is estimated at 1004 hPa. Current environmental conditions are marginal in the lower levels (indirect inflow equatorward, and weak trade inflow southward), and aloft (moderate northeasterly vertical wind shear). Available numerical weather prediction models forecast a southward movement and a slow deepening within the next three days, due to persistent marginal environmental conditions.

For the area at the extreme east of the basin, the potential for the development of a tropical depression is poor for the next 3 days.

[euro6208]

AN AREA OF CONVECTION HAS PERSISTED NEAR 5.7S 85.6E,
APPROXIMATELY 770 NM WEST-NORTHWEST OF THE COCOS ISLANDS. RECENT
ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS DEEP CONVECTION
PERSISTING ALONG THE NORTHERN AND EASTERN PERIPHERIES OF AN
ELONGATED LLCC. THIS DISTURBANCE LIES EQUATORWARD OF AN UPPER LEVEL
RIDGE AXIS, IN AN AREA OF MODERATE EASTERLY VERTICAL WIND SHEAR AND
FAVORABLE WESTWARD AND EQUATORWARD OUTFLOW ALOFT. VERTICAL WIND
SHEAR IS EXPECTED TO CONTINUE IMPACTING THIS DISTURBANCE FOR THE
NEXT DAY OR TWO, RESULTING IN SLOW CONSOLIDATION. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1005 MB. BECAUSE THE LLCC IS JUST
BEGINNING TO DEVELOP AND UPPER LEVEL CONDITIONS ARE LESS THAN
OPTIMAL, THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL
CYCLONE WITHIN THE NEXT 24 HOURS IS LOW.

[euro6208]

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 5.7S 85.6E
IS NOW LOCATED NEAR 7.5S 83.1E, APPROXIMATELY 640 NM EAST OF DIEGO
GARCIA. RECENT ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS
PERSISTENT DEEP CONVECTION ALONG THE SOUTHERN PERIPHERY OF A BROAD
LLCC. A 281409Z SSMIS 37GHZ IMAGE DEPICTS A BROAD LLCC WITH
CONVECTIVE BANDING WRAPPING FROM THE SOUTH QUADRANT INTO THE NORTH
QUADRANT OF THE LLCC. THIS DISTURBANCE LIES EQUATORWARD OF AN UPPER
LEVEL RIDGE AXIS, IN AN AREA OF MODERATE EASTERLY VERTICAL WIND
SHEAR AND FAVORABLE WESTWARD AND EQUATORWARD OUTFLOW ALOFT. VERTICAL
WIND SHEAR IS EXPECTED TO CONTINUE IMPACTING THIS DISTURBANCE FOR
THE NEXT DAY OR TWO, RESULTING IN SLOW CONSOLIDATION. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1005 MB. BECAUSE THE LLCC IS
JUST BEGINNING TO DEVELOP AND UPPER LEVEL CONDITIONS ARE LESS THAN
OPTIMAL, THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL
CYCLONE WITHIN THE NEXT 24 HOURS REMAINS LOW.

[euro6208]

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 8.8S 82.2E,
IS NOW LOCATED NEAR 9.4S 85.2E, APPROXIMATELY 760 NM EAST OF DIEGO
GARCIA. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS AN AREA OF
DEEP CONVECTION FLARING OVER THE WESTERN SEMI-CIRCLE OF AN ELONGATED
AND FULLY EXPOSED LLCC. A 300638Z OCEANSAT IMAGE SHOWS A DEFINED BUT
ELONGATED CIRCULATION EMBEDDED WITHIN THE MONSOON TROUGH. THIS
DISTURBANCE LIES EQUATORWARD OF THE UPPER-LEVEL SUBTROPICAL RIDGE
AXIS IN AN AREA OF MODERATE TO STRONG VERTICAL WIND SHEAR AND GOOD
DIFLUENCE ALOFT. DYNAMIC MODELS INDICATE SLOW CONSOLIDATION OVER THE
NEXT TWO DAYS AS VWS RELAXES. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1005 MB. DUE TO THE LACK OF CONSOLIDATION AND HIGH VWS,
THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS REMAINS LOW.

[supercane4867]

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 9.4S 85.2E
IS NOW LOCATED NEAR 9.3S 85.8E, APPROXIMATELY 790 NM EAST OF DIEGO
GARCIA. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS AN EXPOSED
LOW-LEVEL CIRCULATION CENTER (LLCC) WITH FLARING DEEP CONVECTION
OVER THE WEST QUADRANT. A 301534Z METOP-A IMAGE INDICATES AN
IMPROVING, DEFINED LLCC WITH CONVECTIVE BANDING WRAPPING INTO THE
BROAD CENTER. A 301534Z ASCAT IMAGE DEPICTS AN ELONGATED CIRCULATION
WITH 20 TO 25 KNOT WINDS. OVER THE PAST 24 HOURS, THE UPPER-LEVEL
ENVIRONMENT HAS IMPROVED SLIGHTLY WITH A WEAK ANTICYCLONE POSITIONED
NEAR THE LLCC AND IMPROVED POLEWARD OUTFLOW INTO A DEEP SHORTWAVE
TROUGH TO THE SOUTH. HOWEVER, VERTICAL WIND SHEAR HAS REMAINED
MODERATE TO STRONG (20 TO 30 KNOTS). 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 UPGRADED TO
MEDIUM.

[Grifforzer]

At the extreme east of the basin: satellite imagery show a well defined low level circulation center at present time, near 9.3S 85.5E tracking eastwards at about 7 knots. According to numerical weather prediction fields, conditions could become more conducive for development over the area between Tuesday and Wednesday: improving low level convergence associated with a trade winds surge from the southwest associated with low shear.

For the area at the extreme east of the basin, the potential for development of a tropical depression is poor tomorrow and become fair on Tuesday and beyond.

information from 30Dec 2012 Réunion's ITCZ bulletin.

[euro6208]

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 10.4S 85.5E
IS NOW LOCATED NEAR 10.3S 85.0E, APPROXIMATELY 760 NM EAST-SOUTHEAST
OF DIEGO GARCIA. ANIMATED INFRARED SATELLITE IMAGERY DEPICTS
CONVECTION BUILDING OVER AN ELONGATED LOW LEVEL CIRCULATION CENTER
(LLCC). A RECENT 311605Z ASCAT PASS INDICATES THE LLCC REMAINS
ELONGATED, WITH CENTRAL WINDS BETWEEN 20 TO 25 KNOTS. UPPER LEVEL
ANALYSIS INDICATES THE LLCC IS LOCATED JUST EQUATORWARD OF A
SUBTROPICAL RIDGE (STR) AXIS, WHICH IS PROVIDING GOOD EQUATORWARD
OUTFLOW. ADDITIONALLY, THE LLCC HAS AN IMPROVING POLEWARD CHANNEL
AND IS IN A LOW TO MODERATE VERTICAL WIND SHEAR (VWS) ENVIRONMENT
(10 TO 20 KNOTS). MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT
20 TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR
1004 MB. BASED ON THE ELONGATION OF THE LLCC AND MODERATE VWS, THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS REMAINS MEDIUM.

[supercane4867]

WTXS21 PGTW 012330
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
170 NM EITHER SIDE OF A LINE FROM 7.9S 85.7E TO 11.6S 79.6E 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 27 TO 32 KNOTS. METSAT IMAGERY AT 012030Z
INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 8.9S 84.5E. THE
SYSTEM IS MOVING WEST-NORTHWESTWARD AT 08 KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 9.2S
84.5E, IS NOW LOCATED NEAR 8.9S 84.5E, APPROXIMATELY 720 NM EAST OF
DIEGO GARCIA. ANIMATED INFRARED SATELLITE IMAGERY SHOWS THE LOW
LEVEL CIRCULATION CENTER (LLCC) HAS CONTINUED TO CONSOLIDATE OVER
THE PAST FEW HOURS AND IS BEGINNING TO MOVE UNDER THE PERSISTENT
DEEP CONVECTION. UPPER LEVEL ANALYSIS INDICATES THE LLCC REMAINS
LOCATED EQUATORWARD OF A SUBTROPICAL RIDGE AXIS, WHICH IS CREATING
MODERATE LEVELS OF VERTICAL WIND SHEAR (VWS) (10 TO 20 KNOTS).
STRONGER LEVELS OF VWS TO THE NORTH OF THE LLCC ARE HELPING TO
ENHANCE THE EQUATORWARD OUTFLOW CHANNEL. SEA SURFACE TEMPERATURES
(SSTS) IN THE VICINITY OF THE LLCC ARE FAVORABLE FOR FURTHER
DEVELOPMENT (28 TO 30 DEGREES CELSIUS). MINIMUM SEA LEVEL PRESSURE
IS ESTIMATED TO BE NEAR 1000 MB. BASED ON THE IMPROVING LLCC
STRUCTURE AND FAVORABLE SSTS, 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
022330Z.//

[Hurricane_Luis]

Invest 97S

[supercane4867]

TCFA cancelled

[euro6208]

WTXS21 PGTW 032200
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT CANCELLATION//
REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/022321Z JAN 13//
AMPN/REF IS TROPICAL CYCLONE FORMATION ALERT (WTXS21 PGTW 022330)//
RMKS/
1. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 9.3S
84.9E IS NOW LOCATED NEAR 9.6S 81.0E, APPROXIMATELY 525 NM EAST-
SOUTHEAST OF DIEGO GARCIA. ANIMATED INFRARED SATELLITE IMAGERY
DEPICTS A SHARP DECREASE IN DEEP CONVECTION OVER THE PAST SIX HOURS.
A 031552Z METOP-A IMAGE INDICATES AN ELONGATED LOW-LEVEL CIRCULATION
CENTER (LLCC) WITH WEAK, SHALLOW CONVECTIVE BANDING. A 031552Z ASCAT
IMAGE SHOWS AN ELONGATED CIRCULATION WITH 20 TO 25 KNOT WINDS OVER
THE SOUTHERN SEMI-CIRCLE AND ONLY 15 TO 20 KNOT WINDS OVER THE
NORTHERN SEMI-CIRCLE. THE LLCC HAS TRACKED SLOWLY WESTWARD UNDER THE
STEERING INFLUENCE OF THE LOW-LEVEL SUBTROPICAL RIDGE TO THE SOUTH
AND REMAINS UNDER STRONG (40 KNOTS) VERTICAL WIND SHEAR.
ADDITIONALLY, DYNAMIC MODEL GUIDANCE HAS BACKED OFF ON DEVELOPMENT
WITHIN THE NEXT 36 HOURS. BASED ON THIS EVIDENCE, THE SYSTEM WILL BE
MONITORED CLOSELY FOR POTENTIAL DEVELOPMENT. 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 DOWNGRADED TO MEDIUM. THIS CANCELS REF A.//
NNNN

[euro6208]

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 10.5S
80.9E, IS NOW LOCATED NEAR 11.3S 80.5E, APPROXIMATELY 535 NM EAST-
SOUTHEAST OF DIEGO GARCIA. ANIMATED MSI SHOWS A WEAKLY ORGANIZED
LLCC, WITH A LACK OF CENTRAL CONVECTION. CONVECTION HAS BEEN
FLARING OVER THE PAST 12 TO 24 HOURS ALONG THE OUTER PERIPHERY OF
THE LLCC. THE LLCC HAS BEEN MOVING ERRATICALLY, WITH THE MOST
RECENT MOTION TO THE SOUTHEAST, AND REMAINS UNDER MODERATE (20
KNOTS) VWS. ADDITIONALLY, DYNAMIC MODEL GUIDANCE SHOWS THE LLCC
SLOWLY DEVELOPING BUT HAS BACKED OFF ON DEVELOPMENT WITHIN THE NEXT
24 TO 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 REMAINS MEDIUM.

[cycloneye]

Thanks supercane for letting us know. This thread is back and the other one will be deleited.

[supercane4867]

97S is probably the longest-lived invest on record, it has been around for 13 days

[euro6208]

97S is probably the longest-lived invest on record, it has been around for 13 days

i've seen longer...

[supercane4867]

18z GFS 384HR



LOL

[Hurricane_Luis]

Invest 97S



Looks like a Tropical Cyclone already!

[Grifforzer]

AWIO20 FMEE 111144
TROPICAL CYCLONE CENTER / RSMC LA REUNION / METEO-FRANCE
BULLETIN FOR CYCLONIC ACTIVITY AND SIGNIFICANT TROPICAL WEATHER IN
THE SOUTHWEST INDIAN OCEAN
DATE: 2013/01/11 AT 1200 UTC

Area of disturbed weather East of the basin :

Taking benefit of the strengthening transequatorial low level monsoon inflow and of a good
polewards upper level outflow, the low has organized since Thursday late. As northeasterly vertical windshear decreased aloft, convective activity has developed near the low circulation centre. It remains however fluctuating and keeps on undergoing a north-easterly wind shear constraint, low level vortex is therefore partially exposed in the north of the deep
convective activity that extends up to 300 Nm from the centre in the southern semi-circle.

At 0900Z, the LLCC is located near 12.9S/80.5E slowly drifting northwestwards over the past 6 hours. Oscat 0633Z swath reveals a 15/20 kt well defined clockwise circulation locally reaching 25/30 kt in the southern semi-circle due to the gradient effect with the subtropical high pressures. MSLP is estimated at 1004 hPa thanks to buoy 53006.

On and after Sunday, upper level environmental conditions are expected to improve. The wind shear becomes weak , with good divergence aloft in relationship with the strong aforementioned polewards outflow channel and with an additional but relatively weak outflow channel building equatorward.

ECMWF and ALADIN NWP models forecast a significant intensification next weak on a
northwestwards track at short range on the steering influence of the low level subtropical ridge existing southward then at medium range on a southwestwards track under the steering influence of a mid-level low in the south and a mid-level ridge building in the east.

At every forecast lead time , synoptic environment shows several possible steering influences (mid level northwesterlies equatorward, a building mid-level ridge in the east, a cut-off in the south and a subtropical ridge in the southwest). Northwestwards then southwestwards expected motion should therefore be slow.

For the next 36 hours, potential for development of a tropical depression remains poor but is
upgraded to moderate to fair beyond.

[Meow]

Finally became Tropical Disturbance 6. Look at its weird past track.



WTIO30 FMEE 121250
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER: 1/6/20122013
1.A TROPICAL DISTURBANCE 6
2.A POSITION 2013/01/12 AT 1200 UTC:
WITHIN 20 NM RADIUS OF POINT 11.8 S / 80.7 E
(ELEVEN DECIMAL EIGHT DEGREES SOUTH AND EIGHTY DECIMAL SEVEN DEGREES EAST)
MOVEMENT : NORTH 2 KT
3.A DVORAK ANALYSIS: 2.0/2.0/D 0.5/18 H
4.A CENTRAL PRESSURE: 1001 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 25 KT
RADIUS OF MAXIMUM WINDS (RMW) :37 KM
6.A EXTENSION OF WIND BY QUADRANTS (KM):
7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1008 HPA / 400 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : MEDIUM
1.B FORECASTS:
12H: 2013/01/13 00 UTC: 11.6 S / 79.8 E, MAX WIND=030 KT, TROPICAL DEPRESSION
24H: 2013/01/13 12 UTC: 11.8 S / 79.3 E, MAX WIND=030 KT, TROPICAL DEPRESSION
36H: 2013/01/14 00 UTC: 12.2 S / 78.8 E, MAX WIND=035 KT, MODERATE TROPICAL STORM
48H: 2013/01/14 12 UTC: 12.9 S / 78.4 E, MAX WIND=045 KT, MODERATE TROPICAL STORM
60H: 2013/01/15 00 UTC: 13.3 S / 78.1 E, MAX WIND=055 KT, SEVERE TROPICAL STORM
72H: 2013/01/15 12 UTC: 13.6 S / 78.0 E, MAX WIND=060 KT, SEVERE TROPICAL STORM
2.B LONGER-RANGE OUTLOOK :
96H: 2013/01/16 12 UTC: 14.0 S / 77.9 E, MAX WIND=070 KT, TROPICAL CYCLONE
120H: 2013/01/17 12 UTC: 14.0 S / 77.1 E, MAX WIND=085 KT, TROPICAL CYCLONE
2.C ADDITIONAL INFORMATIONS:
T=2.0-, CI=2.0-.
AS THE EASTERLY VERTICAL WIND SHEAR DECREASED ALOFT, SYSTEM HAS ORGANIZED DURING LAST BNIGHT. CONV
ECTION HAS CONSOLIDATED OVER THE CENTER SINCE THE END OF THE NIGHT. LOW LEVEL CIRCULATION HAS IMPR
OVED ACCORDING TO THE LAST TRMM AT 2316Z, LAST ASCAT DATA SHOWS A MORE SYMETRICAL STRUCTURE OF THE
WINDS.
THE SLIGHT EASTERLY PERSISTENET CONSTRAINTE IS EXPECTED TO WEAKEN CLEARLY ON SUNDAY, THEN UPPER LE
VEL ENVIRONMENT BECOME MORE FAVOURABLE TO INTENSIFICATION, MAINLY ON MONDAY WITH THE BUILDING OF A
SECOND OUTFLOW CHANNEL, BUT THE SLOW SPEED OF DEPLACEMENT SHOULD LIMITED THE INTENSIFICATION POTE
NTIAL.
THE SYSTEM IS FORECASTED TO TRACKER UNDER THE EFFECT OF COMBINED AND
ANTAGONIST STEERING FLOWS, FIRST WESTWARDS ON THE NORTHERN EDGE OF THE LOW LEVEL SUBTROPICAL RIDGE
, BUT COMBINED WITH THE STEERING INFLUENCE OF THE EQUATORIAL RIDGE.THEN TOWARDS SOUTHWEST ON MOND
AY UNDER THE STEERIN EFFLUENCE OF A MID-LEVEL LOW IN THE SOUTH AND A BUILDING MID-LEVEL RIGDE IN T
HE EAST.ON WENESDAY, THE SYSTEME TRACKS WESTWARDS AS THE RIDGE IS LOCATED SOUTH, BUT ALWAYS WITH S
LOW SPEED DUE TO THE PERISTENTE EQUATORIAL MID-LEVEL RIDGE.