SWIO: EX ALENGA - Tropical Low

[Aussie_Thunder]

WTXS22 PGTW 032030
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
REF/A/MSG/NAVMARFCSTCEN PEARL HARBOR HI/030821DEC2011//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 10.4S 94.2E TO 13.6S 88.8E
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 IM-
AGERY AT 032030Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 11.2S 93.6E. THE SYSTEM IS MOVING SOUTHWESTWARD AT 10
KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 11.2S
93.1E IS NOW LOCATED NEAR 11.3S 93.4E, APPROXIMATELY 200 NM WEST OF
THE COCOS ISLANDS. RECENT ANIMATED INFRARED SATELLITE IMAGERY SHOWS
INCREASED CONVECTIVE CONSOLIDATION OVER AN INCREASINGLY MORE
ORGANIZED LOW LEVEL CIRCULATION CENTER. MICROWAVE IMAGERY (031216Z
SSMIS AND 031604 AMSU) SHOWS DEEPENING CONVECTION WRAPPING INTO THE
SYSTEM CENTER FROM THE SOUTHWEST. RECENT SCATTEROMETRY DATA
INDICATES 30 KNOT WINDS NEAR THE SYSTEM CENTER AND ANIMATED WATER
VAPOR IMAGERY SHOWS IMPROVED OUTFLOW IN ALL QUADRANTS. UPPER LEVEL
ANALYSIS INDICATES THAT THE LLCC IS LOCATED JUST NORTH OF THE
SUBTROPICAL RIDGE AXIS IN AN AREA OF MODERATE VERTICAL WIND SHEAR
(VWS). AS THE SYSTEM CONTINUES TO TRACK SOUTHWESTWARD, VWS SHOULD
RELAX AND ALLOW FOR FURTHER DEVELOPMENT. NUMERICAL MODELS CONTINUE
TO HINT AT TROPICAL CYCLONE (35 KNOTS) DEVELOPMENT WITHIN THE RANGE
OF 18 TO 48 HOURS. SEA SURFACE TEMPERATURES REMAIN FAVORABLE AT 26-
27 DEGREES CELSIUS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT
27 TO 32 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED NEAR 1000
MB. DUE TO INCREASED CONSOLIDATION OF THE LLCC, RECENT SCATTEROMETRY
DATA INDICATING 30 KNOT CENTRAL WINDS, AND AN IMPROVING UPPER LEVEL
ENVIRONMENT, 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
042030Z.
4. SEE REF A FOR DETAILS ON A TROPICAL CYCLONE FORMATION ALERT
LOCATED NEAR 11.9S 68.9E.//
NNNN



Personal Forecast Disclaimer:
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

Models have been indicating formation in this area since late October for a Tropical LOW/ Weak Tropical cyclone, conditions look marginal for the system to become anything too serious but conditions such as VWS have improved over the last 24 hours, an upper level trough is indicated to interact with the system in a few days time (Tue/Wed)which will obviously kill it off before it reaches the Australian coastline.

[Chacor]

Looks to be moving into the MF area.

IDW10800
Australian Government Bureau of Meteorology
Western Australia

Tropical Cyclone three-day outlook for the Western Region
Issued at 2:00pm WST on Sunday the 4th of December 2011
Valid until midnight WST Wednesday


Existing Cyclones in the Western region:
Nil.

Potential Cyclones:
At midday WST a low was located near 11.4S 91.3E. The low is moving towards the
southwest and is likely to cross 90E late Sunday or early Monday. The low may
develop into a cyclone during Monday or Tuesday west of 90E. The system may
re-enter the Western region during Wednesday.

Likelihood of this system being a tropical cyclone in the Western Region:
Monday :Low [out of area]
Tuesday :Low [out of area]
Wednesday :Moderate

There are no other significant lows in the region and none are expected to
develop over the next three days.


NOTES: Development Potential is an estimate of the chance of each system being a
tropical cyclone in the Region for each day.
Very Low: less than 5% Low: 5% - 20%,
Moderate: 20% - 50% High: Over 50%

The Western Region refers to the Indian Ocean between Longitudes 90-125E and
south of 10S.
Further information on Tropical Cyclones is available at:
http://www.bom.gov.au/cyclone/

[Grifforzer]

Tropical Depression
12.2S 88.0E
10 min winds: 30 knots
Gusts: 45 knots
Pressure: 996 hPa
Dvorak: T2.5
Additional Information: Increasing

source: http://www.mtotec.com/

---------------------------------------

Joint Typhoon Warning Center cyclone warning

** WTXS31 PGTW 050300 ***
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 01S (ONE) WARNING NR 001//
RMKS/
1. TROPICAL CYCLONE 01S (ONE) 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:
050000Z --- NEAR 12.3S 87.9E
MOVEMENT PAST SIX HOURS - 285 DEGREES AT 11 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
110 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
105 NM NORTHWEST QUADRANT
REPEAT POSIT: 12.3S 87.9E
---
FORECASTS:
12 HRS, VALID AT:
051200Z --- 12.6S 86.8E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
110 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
105 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 225 DEG/ 03 KTS
---
24 HRS, VALID AT:
060000Z --- 13.0S 86.4E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
110 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
105 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 130 DEG/ 05 KTS
---
36 HRS, VALID AT:
061200Z --- 13.6S 87.1E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
115 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
115 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 120 DEG/ 08 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
070000Z --- 14.4S 88.5E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 125 NM NORTHEAST QUADRANT
120 NM SOUTHEAST QUADRANT
105 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 115 DEG/ 13 KTS
---
72 HRS, VALID AT:
080000Z --- 16.6S 93.3E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 125 NM NORTHEAST QUADRANT
120 NM SOUTHEAST QUADRANT
105 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 120 DEG/ 13 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
090000Z --- 19.1S 98.3E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
EXTRATROPICAL
---
REMARKS:
050300Z POSITION NEAR 12.4S 87.6E.
TROPICAL CYCLONE (TC) 01S, LOCATED APPROXIMATELY 525 NM WEST OF THE
COCOS ISLANDS, HAS TRACKED WEST-NORTHWESTWARD AT 11 KNOTS OVER THE
PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY SHOWS A RAPIDLY
CONSOLIDATING LOW LEVEL CIRCULATION CENTER (LLCC) WITH DEEP CENTRAL
CONVECTION. A 042325Z SSMIS 37 GHZ MICROWAVE PASS SHOWS A FORMATIVE
MICROWAVE EYE AND TIGHTLY CURVED BANDING WRAPPING INTO THE LLCC. THE
CURRENT INTENSITY IS BASED ON DVORAK ESTIMATES FROM PGTW AND KNES
RANGING FROM 35 TO 45 KNOTS. THE CURRENT POSITION IS BASED ON THE
AFOREMENTIONED MICROWAVE IMAGE AND THE 04/2332Z PGTW SATELLITE FIX
WITH GOOD CONFIDENCE. UPPER LEVEL ANALYSIS INDICATES THAT TC 01S IS
LOCATED UNDER THE RIDGE AXIS IN A REGION OF STRONG DIFFLUENT FLOW
ALOFT AND LOW VERTICAL WIND SHEAR. ANIMATED WATER VAPOR IMAGERY
SHOWS GOOD OUTFLOW IN THE WESTERN AND SOUTHERN SEMI-CIRCLES, BUT
OUTFLOW ALONG THE EASTERN PERIPHERY IS SOMEWHAT INHIBITED BY
EASTERLY FLOW ALOFT. THE SYSTEM IS CURRENTLY TRACKING ALONG THE
NORTHWESTERN PERIPHERY OF A FINGER OF THE SUBTROPICAL RIDGE
EXTENDING FROM SOUTH OF JAKARTA INDONESIA. TC 01 IS EXPECTED TO
CONTINUE TRACKING GENERALLY WESTWARD FOR THE NEXT 12 TO 24 HOURS
BEFORE AN APPROACHING MID-LATITUDE TROUGH WEAKENS THE RIDGE AND
ALLOWS THE SYSTEM TO RECURVE AHEAD OF THE TROUGH AND BEGIN EXTRA-
TROPICAL TRANSITION (ET). THE SYSTEM IS EXPECTED TO GRADUALLY
INTENSIFY AS THE UPPER LEVEL ENVIRONMENT AND SEA SURFACE
TEMPERATURES REMAIN FAVORABLE THROUGH THE FIRST 48 TO 72 HOURS OF
THE FORECAST. TC 01S IS FORECAST TO COMPLETE ET BY TAU 96.
NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THE TIMING OF
RECURVATURE AND OVERALL FORECAST TRACK, THEREFORE THIS FORECAST
REMAINS CLOSE TO MODEL CONSENSUS. THIS WARNING SUPERSEDES AND
CANCELS REF A, NAVMARFCSTCEN 042021Z DEC 11 TROPICAL CYCLONE
FORMATION ALERT (WTXS22 PGTW 042030) MAXIMUM SIGNIFICANT WAVE HEIGHT
AT 050000Z IS 12 FEET. NEXT WARNINGS AT 051500Z AND 060300Z.//

[Grifforzer]

Mauritius Meteorological Services
** WTMA20 FIMP 050600 ***
DATE: 05 DECEMBER 2011

Latest satellite imagery and analysis indicate that the tropical depression located at 05/0530z near 12.3S 87.9E has intensified into a moderate tropical storm. It has been named "Alenga"

Movement generally west at about 9 knots.

[francis327]

[P.K.]

First advisory on 01R.

WTIO30 FMEE 050659
RSMC / TROPICAL CYCLONE CENTRE / LA REUNION
TROPICAL CYCLONE TECHNICAL BULLETIN (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER : 1/1/20112012
1.A MODERATE TROPICAL STORM 1 (ALENGA)
2.A POSITION 2011/12/06 AT 0600 UTC :
WITHIN 20 NM OF POINT 12.3S / 87.9E
(TWELVE DECIMAL THREE DEGREES SOUTH AND EIGHTY SEVEN DECIMAL NINE
DEGREES EAST)
MOVEMENT : WEST-SOUTH-WEST 5 KT
3.A DVORAK ANALYSIS : 3.0/3.0/D 1.0/18 H
4.A CENTRAL PRESSURE : 995 HPA
5.A MAX AVERAGE WIND SPEED (10 MN) : 40 KT
RADIUS OF MAXIMUM WINDS (RMW) : 50 KM
6.A EXTENSION OF WINDS BY QUADRANTS (KM) :
28 KT NE: 75 SE: 85 SO: 85 NO: 75
34 KT NE: 110 SE: 170 SO: 170 NO: 150
7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM) : 1007 HPA / 570 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : MODERATE
1.B FORECASTS :
12H: 2011/12/05 18 UTC: 12.6S/87.3E, MAX WIND=50KT, SEVERE TROP.
STORM
24H: 2011/12/06 06 UTC: 13.0S/87.5E, MAX WIND=60KT, SEVERE TROP.
STORM
36H: 2011/12/06 18 UTC: 13.6S/88.7E, MAX WIND=70KT, TROPICAL CYCLONE
48H: 2011/12/07 06 UTC: 14.5S/90.7E, MAX WIND=80KT, TROPICAL CYCLONE
60H: 2011/12/07 18 UTC: 15.9S/93.4E, MAX WIND=80KT, TROPICAL CYCLONE
72H: 2011/12/08 06 UTC: 17.0S/95.5E, MAX WIND=70KT, TROPICAL CYCLONE
2.B LONGER-RANGE OUTLOOK :
96H: 2011/12/09 06 UTC: 18.9S/99.7E, MAX WIND=40KT, MODERATE TROP.
STORM
120H: 2011/12/10 06 UTC: 20.1S/101.3E, MAX WIND=30KT, TROPICAL
DEPRESSION
2.C ADDITIONAL INFORMATION :
T=3.0 CI=3.0
THE SYSTEM HAS RAPIDLY INTENSIFIED DURING THE LAST 12 HOURS, WITH
VIGOROUS CONVECTION STARTED IN THE WESTERN SEMI-CIRCLE AND WRAPPED
AROUND THE CENTER.
SSMIS AND WINDSAT PASS OF THIS MORNING DEPICT A WELL DEFINED LOW
LEVEN CENTER WITH
EVIDENCE OF A LOW LEVEL EYE FEATURE. CONSEQUENTLY, THE SYSTEM HAS
BEEN NAMED ALENGA
BY THE MAURITIUS METEOROLOGICAL AGENCY.
CURRENT MOTION IS A SLOWING WESTWARDS TRACK OVER THE NORTHWESTERN
EDGE OF THE STR.
AS A HIGH TO MID LEVEL MID-LAT TROUGH IS APPROACHING TO THE SOUTH AND
AN EQUATORIAL RIDGE
SHOULD BUILD TO THE NORTHEAST OF THE SYSTEM, ALENGA IS FORECAST TO
MOVE LITTLE WITHIN
THE NEXT 24 HOURS BEFORE ACCELERATESTOWARDS THE SOUTHESAT. ALL NWP
MODELS AGREE WITH THIS
ALTHOUGH THERE IS SOME SUBSTANTIAL SPREAD IN THE SPEED FORECAST.
CURRENT FORECAST IS BASED
ON A CONSENSUSOF ALL AVAILABLE NWP MODELS. ON THIS FORECAST, THE
SYSTEM SHOULD PASS EAST OF
90E TUESDAY NIGHT OR WENESDAY MORNING.
THERE IS STILL A LITTLE BIT OF EASTNORTHEASTERLY SHEAR THIS MORNING,
BUT IT IS FORECAST TO ABATE SOON.
GIVEN THE FAVOURABLE SST, STEADY INTENSIFICATION AT LEAST AT THE
CLIMATOLOGICAL RATE IS FORECAST
AND ALENGA COULD BECOME A TROPICAL CYCLONE WITHIN THE NEXT 48 HOURS.
THURSDAY, AN INCREASE OF VWS AND COOLER SST SHOULD PRODUCE
SIGNIFICANT WEAKENING OF THE SYSTEM.=

[Aussie_Thunder]

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org For Official Information please refer to the NHC and NWS products.


Not yet "Officially" named Alenga, still designated TC 01S(one), but forecasts by JTWC and La Reunion RMSC indicate naming rights will fall to La Reunion occuring in 24 hours or so...

Track map from La Reunion


original link:http://www.meteo.fr/temps/domtom/La_Reunion/meteoreunion2/

[Chacor]

Er, given it's west of 90E, Australia have no naming rights over this. This is "officially" Alenga.

WTIO30 FMEE 051242
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER: 2/1/20112012
1.A SEVERE TROPICAL STORM 1 (ALENGA)
2.A POSITION 2011/12/05 AT 1200 UTC:
WITHIN 20 NM RADIUS OF POINT 12.2 S / 87.4 E
(TWELVE DECIMAL TWO DEGREES SOUTH AND EIGHTY SEVEN DECIMAL FOUR DEGREES EAST)
MOVEMENT : WEST 3 KT
3.A DVORAK ANALYSIS: 3.5/3.5/D 0.5/6 H
4.A CENTRAL PRESSURE: 989 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 50 KT RADIUS OF MAXIMUM WINDS (RMW) :28 KM
6.A EXTENSION OF WIND BY QUADRANTS (KM): 28 KT NE: 110 SE: 170 SW: 170 NW: 150
34 KT NE: 80 SE: 110 SW: 110 NW: 80
48 KT NE: 30 SE: 30 SW: 30 NW: 30
7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1007 HPA / 1100 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP
1.B FORECASTS:
12H: 2011/12/06 00 UTC: 12.7 S / 87.0 E, MAX WIND=060 KT, SEVERE TROPICAL STORM 24H: 2011/12/06 12 UTC: 13.2 S / 87.7 E, MAX WIND=070 KT, TROPICAL CYCLONE
36H: 2011/12/07 00 UTC: 14.1 S / 89.3 E, MAX WIND=070 KT, TROPICAL CYCLONE
48H: 2011/12/07 12 UTC: 15.4 S / 91.8 E, MAX WIND=060 KT, SEVERE TROPICAL STORM 60H: 2011/12/08 00 UTC: 17.0 S / 94.7 E, MAX WIND=050 KT, SEVERE TROPICAL STORM 72H: 2011/12/08 12 UTC: 18.2 S / 97.0 E, MAX WIND=040 KT, EXTRATROPICAL SYSTEM
2.B LONGER-RANGE OUTLOOK :
96H: 2011/12/09 12 UTC: 19.7 S / 100.1 E, MAX WIND=030 KT, EXTRATROPICAL SYSTEM 120H: 2011/12/10 12 UTC: 20.9 S / 100.8 E, MAX WIND=030 KT, EXTRATROPICAL SYSTEM
2.C ADDITIONAL INFORMATIONS: T=CI=3.5
ALENGA KEEPS ON INTENSIFYING. SSMI MICROWAVE IMAGERY OF 1034Z SHOW A MID-LEVEL EYE FEATURE AND SUGGEST A SIGNIFICANT REDUCTION OF THE RMW. WITH THIS CLEAR SIGNS OF INTENSIFICATION, ALENGA IS NOW UPGRADED AS A SEVERE TROPICAL STORM.
CURRENT MOTION IS STILL A SLOWING WESTWARDS TRACK OVER THE NORTHWESTERN EDGE OF SUBTROPICAL RIDGE. AS A HIGH TO MID LEVEL TROUGH IS APPROACHING TO THE SOUTH BETWEEN 80E AND 90E (CF WATER VAPOR IMAGERY) AND AN EQUATORIAL RIDGE SHOULD BUILD TO THE NORTHEAST OF THE SYSTEM, ALENGA IS FORECAST TO MOVE LITTLE WITHIN THE NEXT 24 HOURS BEFORE ACCELERATES TOWARDS THE SOUTHEAST.ALL NWP MODELS AGREE WITH THIS ALTHOUGH THERE IS SOME SUBSTANTIAL SPREAD IN THE SPEED FORECAST. CURRENT FORECAST IS BASED ON A CONSENSUS OF ALL AVAILABLE NWP MODELS. ON THIS FORECAST, THE SYSTEM SHOULD PASS EAST OF 90E TUESDAY NIGHT OR WEDNESDAY MORNING.
THE SHEAR CONTINUE TO WEAKEN. GIVEN THE FAVOURABLE SST, STEADY INTENSIFICATION AT LEAST AT A CLIMATOLOGICAL RATE IS FORECAST AND ALENGA COULD BECOME A TROPICAL CYCLONE TOMORROW. THURSDAY, AN INCREASE OF VWS AND COOLER SST SHOULD PRODUCE SIGNIFICANT WEAKENING OF THE SYSTEM. EXTRATROPICAL TRANSITION IS NOW EXPECTED AT THIS TIME.

[P.K.]

WTIO30 FMEE 051822
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER: 3/1/20112012
1.A SEVERE TROPICAL STORM 1 (ALENGA)
2.A POSITION 2011/12/05 AT 1800 UTC:
WITHIN 20 NM RADIUS OF POINT 13.1 S / 86.9 E
(THIRTEEN DECIMAL ONE DEGREES SOUTH AND EIGHTY SIX DECIMAL
NINE DEGREES EAST)
MOVEMENT : SOUTH-WEST 6 KT
3.A DVORAK ANALYSIS: 4.0/4.0/D 1.0/12 H
4.A CENTRAL PRESSURE: 982 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 55 KT
RADIUS OF MAXIMUM WINDS (RMW) :33 KM
6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 130 SE: 150 SW: 70 NW: 90
34 KT NE: 60 SE: 70 SW: 50 NW: 60
48 KT NE: 40 SE: 40 SW: 40 NW: 40
7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1006 HPA / 1000 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : UNKNOWN
1.B FORECASTS:
12H: 2011/12/06 06 UTC: 14.0 S / 86.8 E, MAX WIND=065 KT, TROPICAL
CYCLONE
24H: 2011/12/06 18 UTC: 14.6 S / 88.3 E, MAX WIND=070 KT, TROPICAL
CYCLONE
36H: 2011/12/07 06 UTC: 15.3 S / 90.3 E, MAX WIND=065 KT, TROPICAL
CYCLONE
48H: 2011/12/07 18 UTC: 16.8 S / 93.0 E, MAX WIND=060 KT, SEVERE
TROPICAL STORM
60H: 2011/12/08 06 UTC: 18.2 S / 95.5 E, MAX WIND=050 KT, SEVERE
TROPICAL STORM
72H: 2011/12/08 18 UTC: 19.2 S / 97.7 E, MAX WIND=040 KT,
EXTRATROPICAL SYSTEM
2.B LONGER-RANGE OUTLOOK :
96H: 2011/12/09 18 UTC: 20.5 S / 100.2 E, MAX WIND=030 KT,
EXTRATROPICAL SYSTEM
120H: 2011/12/10 18 UTC: 21.8 S / 100.3 E, MAX WIND=030 KT,
EXTRATROPICAL SYSTEM
2.C ADDITIONAL INFORMATIONS:
T=CI=4.0-
SINCE 1530Z, ALENGA SHOWS AN IRREGULAR EYE BUT DEEP CONVECTIVE
ACTIVITY REMAINS ASYMMETRIC WITH THE MORE ACTIVE ONE MAINLY LOCATED
IN THE NORTHERN SEMI-CIRCLE.
1522Z ASCAT SWATH SEEMS TO BE BAD RESOLVED.
CURRENT MOTION IS NOW A SOUTH-WESTWARDS TRACK OVER THE NORTHWESTERN
EDGE OF SUBTROPICAL RIDGE. AS A HIGH TO MID LEVEL TROUGH IS
APPROACHING TO THE SOUTH BETWEEN 80E AND 90E (CF WATER VAPOR IMAGERY)
AND AN EQUATORIAL RIDGE SHOULD BUILD TO THE NORTHEAST OF THE SYSTEM,
ALENGA IS FORECAST TO MOVE LITTLE WITHIN THE NEXT 24 HOURS BEFORE
ACCELERATES TOWARDS THE SOUTHEAST.ALL NWP MODELS AGREE WITH THIS
ALTHOUGH THERE IS SOME SUBSTANTIAL SPREAD IN THE SPEED FORECAST.
CURRENT FORECAST IS BASED ON A CONSENSUS OF ALL AVAILABLE NWP MODELS.
ON THIS FORECAST, THE SYSTEM SHOULD PASS EAST OF 90E TUESDAY NIGHT OR
WEDNESDAY MORNING.
THE SHEAR CONTINUE TO WEAKEN. GIVEN THE FAVOURABLE SST, STEADY
INTENSIFICATION AT LEAST AT A CLIMATOLOGICAL RATE IS FORECAST AND
ALENGA COULD BECOME A TROPICAL CYCLONE TOMORROW. THURSDAY, AN
INCREASE OF VWS AND COOLER SST SHOULD PRODUCE SIGNIFICANT WEAKENING
OF THE SYSTEM. EXTRATROPICAL TRANSITION IS NOW EXPECTED AT THIS TIME.=

[francis327]

WTXS31 PGTW 060900
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 01S (ALENGA) WARNING NR 004//
RMKS/
1. TROPICAL CYCLONE 01S (ALENGA) WARNING NR 004
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
060600Z --- NEAR 12.7S 87.3E
MOVEMENT PAST SIX HOURS - 205 DEGREES AT 02 KTS
POSITION ACCURATE TO WITHIN 060 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 - 090 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
REPEAT POSIT: 12.7S 87.3E
---
FORECASTS:
12 HRS, VALID AT:
061800Z --- 13.2S 88.1E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 115 DEG/ 09 KTS
---
24 HRS, VALID AT:
070600Z --- 14.0S 89.7E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
110 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 120 DEG/ 14 KTS
---
36 HRS, VALID AT:
071800Z --- 15.3S 92.2E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
125 NM SOUTHEAST QUADRANT
125 NM SOUTHWEST QUADRANT
140 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 115 DEG/ 15 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
080600Z --- 16.6S 95.0E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 130 NM NORTHEAST QUADRANT
120 NM SOUTHEAST QUADRANT
120 NM SOUTHWEST QUADRANT
130 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 125 DEG/ 12 KTS
---
72 HRS, VALID AT:
090600Z --- 19.2S 99.3E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 145 DEG/ 05 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
100600Z --- 20.9S 100.7E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 120 HR POSIT: 175 DEG/ 03 KTS
---
120 HRS, VALID AT:
110600Z --- 21.9S 100.8E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
060900Z POSITION NEAR 12.8S 87.5E.
TROPICAL CYCLONE (TC) 01S (ALENGA), LOCATED APPROXIMATELY 560 NM WEST
OF THE COCOS ISLANDS, HAS TRACKED SOUTH-SOUTHWESTWARD AT 02 KNOTS
OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY DEPICTS
A MARKED DECREASE IN CONVECTIVE ORGANIZATION OVER THE PAST 12 HOURS
WITH WEAKENING CONVECTIVE BANDING. A 060730Z AMSU IMAGE SHOWS
FRAGMENTED DEEP CONVECTIVE BANDING. THE CURRENT INTENSITY IS
ASSESSED AT 45 KNOTS BASED ON DVORAK INTENSITY ESTIMATES OF 45 KNOTS
FROM ALL AGENCIES. THERE IS FAIR CONFIDENCE IN THE CURRENT POSITION
BASED ON A 060409Z METOP-A IMAGE AS WELL AS THE AFOREMENTIONED
060730Z AMSU IMAGE. TC 01S IS TRACKING SLOWLY ALONG THE WESTERN
PERIPHERY OF A WEAK NEAR-EQUATORIAL RIDGE BUT IS FORECAST TO TURN
EAST-SOUTHEASTWARD TO SOUTHEASTWARD AND ACCELERATE AHEAD OF A DEEP
SHORTWAVE TROUGH. MODEL GUIDANCE SUPPORTS THIS TRACK AND IS TIGHTLY
CLUSTERED THROUGH TAU 72. AFTER TAU 72, TC 01S IS EXPECTED TO SLOW,
WEAKEN AND THEN TURN SOUTHWESTWARD UNDER THE STEERING INFLUENCE OF
THE LOW-LEVEL SUBTROPICAL RIDGE. MODEL GUIDANCE SUPPORTS THIS
SCENARIO WITH THE EXCEPTION OF GFDN. TC 01S IS EXPECTED TO INTENSIFY
UNDER A FAVORABLE ENVIRONMENT THROUGH TAU 36 BUT SHOULD BEGIN TO
WEAKEN BY TAU 48 AS IT BEGINS EXTRA-TROPICAL TRANSITION (ETT) AND
INTERACTS WITH THE UPPER-LEVEL TROUGH. THE SYSTEM IS NOT EXPECTED TO
COMPLETE ETT DUE TO AN INCREASINGLY HOSTILE ENVIRONMENT AND IS NOW
FORECAST TO DISSIPATE BY TAU 120. MAXIMUM SIGNIFICANT WAVE HEIGHT AT
060600Z IS 20 FEET. NEXT WARNINGS AT 062100Z AND 070900Z.//
NNNN

[RobWESTPACWX]

[youtube]http://www.youtube.com/watch?v=pyNLv5bVyLw&feature=player_embedded[/youtube]

Video I just made for this storm, gives you a closer look at it.

[Chacor]

WTIO30 FMEE 061245

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

0.A WARNING NUMBER: 7/1/20112012
1.A MODERATE TROPICAL STORM 1 (ALENGA)

2.A POSITION 2011/12/06 AT 1200 UTC:
WITHIN 21 NM RADIUS OF POINT 13.5 S / 87.5 E
(THIRTEEN DECIMAL FIVE DEGREES SOUTH AND EIGHTY SEVEN DECIMAL FIVE DEGREES EAST)
MOVEMENT : SOUTH 3 KT

3.A DVORAK ANALYSIS: 3.0/3.0/W 0.5/12 H
4.A CENTRAL PRESSURE: 990 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 40 KT
RADIUS OF MAXIMUM WINDS (RMW) :33 KM

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 110 SE: 90 SW: 90 NW: 110
34 KT NE: 70 SE: 60 SW: 60 NW: 70



7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1006 HPA / 1300 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : UNKNOWN

1.B FORECASTS:
12H: 2011/12/07 00 UTC: 14.2 S / 88.7 E, MAX WIND=035 KT, MODERATE TROPICAL STORM
24H: 2011/12/07 12 UTC: 15.2 S / 90.8 E, MAX WIND=035 KT, MODERATE TROPICAL STORM
36H: 2011/12/08 00 UTC: 16.3 S / 93.5 E, MAX WIND=030 KT, TROPICAL DEPRESSION
48H: 2011/12/08 12 UTC: 17.7 S / 96.4 E, MAX WIND=030 KT, TROPICAL DEPRESSION
60H: 2011/12/09 00 UTC: 19.2 S / 99.0 E, MAX WIND=030 KT, EXTRATROPICAL SYSTEM
72H: 2011/12/09 12 UTC: 20.1 S / 100.9 E, MAX WIND=030 KT, EXTRATROPICAL SYSTEM

2.B LONGER-RANGE OUTLOOK :
96H: 2011/12/10 12 UTC: 22.0 S / 102.5 E, MAX WIND=025 KT, EXTRATROPICAL SYSTEM
120H: 2011/12/11 12 UTC: 23.2 S / 101.4 E, MAX WIND=025 KT, EXTRATROPICAL SYSTEM

2.C ADDITIONAL INFORMATIONS:
T=CI=3.0

LAST AVALAIBLE ANIMATED SATELLITE PICTURES DEPICT NEW BLOW UP OF CONVECTION CLOSE TO THE CENTER WITHIN THE LAST 6 HOURS.

IN RELATIONSHIP WITH A MID-LEVEL TROUGH TRANSITING IN ITS SOUTH
ALENGA IS FORECAST TO PROGRESSIVELY ACCELERATE TOWARDS THE SOUTHEAST.

ON AND AFTER THURSDAY, SYSTEM SHOULD UNDERGO A MODERATE WEST-NORTHWESTERLY VERTICAL WINDSHEAR, INTENSITY IS EXPECTED TO DECREASE FASTER, AND SYSTEM SHOULD BEGIN ITS EXTRATROPICAL TRANSITION.

ON THIS FORECAST, THE SYSTEM SHOULD PASS EAST OF 90E WEDNESDAY MORNING.

[Chacor]

IDW10800
Australian Government Bureau of Meteorology
Western Australia

Tropical Cyclone three-day outlook for the Western Region
Issued at 2:00pm WST on Tuesday the 6th of December 2011
Valid until midnight WST Friday


Existing Cyclones in the Western region:
Nil.

Potential Cyclones:
At 8am WST Tuesday, Tropical Cyclone Alenga was located near 12.8S 86.9E, moving
southwest at 9 kilometers per hour. The cyclone is likely to move towards the
southeast and enter the Western region on Wednesday before weakening during
Thursday or Friday.

Likelihood of this system being a tropical cyclone in the Western Region:
Wednesday :High
Thursday :High
Friday :Low

There are no other significant lows in the region and none are expected to
develop over the next three days.


NOTES: Development Potential is an estimate of the chance of each system being a
tropical cyclone in the Region for each day.
Very Low: less than 5% Low: 5% - 20%,
Moderate: 20% - 50% High: Over 50%

The Western Region refers to the Indian Ocean between Longitudes 90-125E and
south of 10S.
Further information on Tropical Cyclones is available at:
http://www.bom.gov.au/cyclone/

[CrazyC83]

This is equivalent to June in the Atlantic, so typical for the start of the season?

[Chacor]

More of July, the season started last month.

[Macrocane]

WTXS31 PGTW 070900
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 01S (ALENGA) WARNING NR 006//
RMKS/
1. TROPICAL CYCLONE 01S (ALENGA) WARNING NR 006
02 ACTIVE TROPICAL CYCLONES IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
070600Z --- NEAR 14.5S 90.2E
MOVEMENT PAST SIX HOURS - 115 DEGREES AT 15 KTS
POSITION ACCURATE TO WITHIN 040 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
095 NM NORTHWEST QUADRANT
REPEAT POSIT: 14.5S 90.2E
---
FORECASTS:
12 HRS, VALID AT:
071800Z --- 15.5S 92.6E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
095 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 120 DEG/ 14 KTS
---
24 HRS, VALID AT:
080600Z --- 16.8S 95.1E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 065 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 120 DEG/ 13 KTS
---
36 HRS, VALID AT:
081800Z --- 18.0S 97.4E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 065 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 130 DEG/ 10 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
090600Z --- 19.2S 99.0E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 065 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 140 DEG/ 04 KTS
---
72 HRS, VALID AT:
100600Z --- 20.6S 100.2E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
095 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 165 DEG/ 03 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
110600Z --- 21.7S 100.5E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 120 HR POSIT: 180 DEG/ 01 KTS
---
120 HRS, VALID AT:
120600Z --- 22.2S 100.5E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
070900Z POSITION NEAR 14.8S 90.8E.
TROPICAL CYCLONE (TC) 01S (ALENGA), LOCATED APPROXIMATELY 415 NM
WEST-SOUTHWEST OF THE COCOS ISLANDS, HAS TRACKED EAST-SOUTHEASTWARD
AT 15 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY (MSI) SHOWS IMPROVED DEEP CONVECTIVE BANDING
WRAPPING INTO A WELL-DEFINED LOW LEVEL CIRCULATION CENTER (LLCC). A
070214Z SSMIS MICROWAVE IMAGE ALSO DEPICTS A TIGHTLY CURVED DEEP
CONVECTIVE BAND WRAPPING AROUND THE NORTHERN PERIPHERY OF THE LLCC.
THE INITIAL POSITION IS BASED WITH FAIR CONFIDENCE ON THE MSI. THE
INITIAL INTENSITY IS BASED ON THE PGTW AND KNES DVORAK ESTIMATES OF
55 KNOTS. OUTFLOW TO THE SOUTHEAST HAS IMPROVED INTO AN UPPER LEVEL
LOW, HOWEVER OUTFLOW TO THE SOUTHWEST IS INHIBITED BY AN UPPER LEVEL
TROUGH. EQUATORWARD OUTFLOW REMAINS FAVORABLE. TC 01S IS CURRENTLY
TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A MID-LEVEL SUBTROPICAL
STEERING RIDGE AND IS EXPECTED TO CONTINUE TRACKING GENERALLY EAST-
SOUTHEASTWARD THROUGHOUT THE FORECAST PERIOD. TC 01S IS FORECAST TO
CONTINUE TO INTENSIFY DUE TO FAVORABLE OUTFLOW ALOFT AND WARM SEA
SURFACE TEMPERATURES. BY TAU 72, THE SYSTEM WILL BEGIN TO RAPIDLY
WEAKEN AS VERTICAL WIND SHEAR ASSOCIATED WITH THE MID-LATITUDE
WESTERLIES INCREASES. TC 01S IS EXPECTED TO DISSIPATE AS A
SIGNIFICANT TROPICAL CYCLONE BY TAU 120, BEFORE COMPLETING EXTRA-
TROPICAL TRANSITION. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT.
THEREFORE, THIS FORECAST IS IN GOOD AGREEMENT WITH MODEL CONSENSUS.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 070600Z IS 20 FEET. NEXT WARNINGS
AT 072100Z AND 080900Z. REFER TO TROPICAL CYCLONE 02S (TWO) WARNINGS
(WTXS32 PGTW) FOR TWELVE-HOURLY UPDATES.//
NNNN

[Macrocane]

ZCZC 487
WTIO30 FMEE 070023
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER: 8/1/20112012
1.A MODERATE TROPICAL STORM 1 (ALENGA)
2.A POSITION 2011/12/07 AT 0000 UTC:
WITHIN 30 NM RADIUS OF POINT 14.5 S / 89.2 E
(FOURTEEN DECIMAL FIVE DEGREES SOUTH AND EIGHTY NINE DECIMAL TWO DEGREES EAST)
MOVEMENT : SOUTH-EAST 8 KT
3.A DVORAK ANALYSIS: 3.0/3.0/S 0.0/6 H
4.A CENTRAL PRESSURE: 995 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 40 KT
RADIUS OF MAXIMUM WINDS (RMW) :52 KM
6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 110 SE: 90 SW: 90 NW: 110
34 KT NE: 70 SE: 60 SW: 60 NW: 70
7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1006 HPA / 1200 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : MEDIUM
1.B FORECASTS:
12H: 2011/12/07 12 UTC: 15.3 S / 91.0 E, MAX WIND=045 KT, MODERATE TROPICAL STORM
24H: 2011/12/08 00 UTC: 16.2 S / 93.8 E, MAX WIND=045 KT, MODERATE TROPICAL STORM
36H: 2011/12/08 12 UTC: 17.7 S / 96.9 E, MAX WIND=040 KT, MODERATE TROPICAL STORM
48H: 2011/12/09 00 UTC: 19.2 S / 99.1 E, MAX WIND=030 KT, TROPICAL DEPRESSION
60H: 2011/12/09 12 UTC: 20.3 S / 100.2 E, MAX WIND=030 KT, EXTRATROPICAL SYSTEM
72H: 2011/12/10 00 UTC: 20.7 S / 99.9 E, MAX WIND=030 KT, EXTRATROPICAL SYSTEM
2.B LONGER-RANGE OUTLOOK :
96H: 2011/12/11 00 UTC: 21.2 S / 98.1 E, MAX WIND=025 KT, EXTRATROPICAL SYSTEM
2.C ADDITIONAL INFORMATIONS:
T=CI=3.0
ON IR IMAGERY, ALENGA SHOW A VERY COLD "CDO LIKE" FEATURE (ALTHOUGH THIS IS USED FOR VISIBLE IMAGE
RY) THAT HAS GAIN IN SIZE DURING THE NIGHT (UP TI 160 NM IN DIAMETER). 2008Z TRMM MW IMAGERY WAS U
SEFUL TO LOCATE THE CENTER AND TO SHOW THAT THE SYSTEM SEEMS TO STILL SUFFER FROM A LACK OF INNER
CORE ORAGANISATION, MAINLY IN THE LOW LEVEL AND IN THE EASTERN SEMI-CIRCLE. CONSEQUENTLY AND ALTHO
UGH THE OVERALL PATTERN IS SIMILAR OR SLIGHTLY BETTER THAN 24 HOURS AGO, THE SYSTEM IS MAINTAIN AT
THE SAME INTENSITY THAN PREVIOUSLY.
ALENGA SEEMS NOW TO SPEED UP TOWARDS THE EAST-SOUTH-EAST AS IT IS CATCHING WITHIN THE WESTNORTHWES
TERLY STEERING FLOW THAT EXISTS AHEAD OF A MID-LEVEL TROUGH TRANSITING IN ITS SOUTH.NO MAJOR CHANG
E FROM THE 12Z NWP CYCLE FOR THE TRACK FORECAST. ALL GUIDANCE CONTINUE TO BE TIGHTLY PACKED UNTIL
DAY 3.
THE SYSTEM HAS STILL A SMALL OPORTUNITY FOR SOME STRENGHENING OVER WARM SST AND AN IMPROVING UPPER
LEVEL DIVERGENCE MAINLY IN THE SOUTHERN SEMI-CIRCLE. ON AND AFTER THURSDAY, SYSTEM SHOULD UNDERGO
A MODERATE WEST-NORTHWESTERLY VERTICAL WINDSHEAR AN MOVE OVER COOLER WATER. INTENSITY IS EXPECTED
TO DECREASE FASTER, AND SYSTEM SHOULD BEGIN ITS EXTRATROPICAL TRANSITION.
THIS IS THE LAST ADVISORY ISSUED BY RSMC LA REUNION FOR THIS SYSTEM. NEXT ADVISORY ISSUED BY PERTH
TCWC.
NNNN

[Macrocane]

IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 0710 UTC 07/12/2011
Name: Tropical Cyclone Alenga
Identifier: 01U
Data At: 0600 UTC
Latitude: 14.3S
Longitude: 89.9E
Location Accuracy: within 20 nm [35 km]
Movement Towards: east southeast [121 deg]
Speed of Movement: 7 knots [13 km/h]
Maximum 10-Minute Wind: 55 knots [100 km/h]
Maximum 3-Second Wind Gust: 75 knots [140 km/h]
Central Pressure: 986 hPa
Radius of 34-knot winds NE quadrant: 90 nm [165 km]
Radius of 34-knot winds SE quadrant: 90 nm [165 km]
Radius of 34-knot winds SW quadrant: 90 nm [165 km]
Radius of 34-knot winds NW quadrant: 90 nm [165 km]
Radius of 48-knot winds NE quadrant: 25 nm [45 km]
Radius of 48-knot winds SE quadrant: 25 nm [45 km]
Radius of 48-knot winds SW quadrant: 25 nm [45 km]
Radius of 48-knot winds NW quadrant: 25 nm [45 km]
Radius of 64-knot winds:
Radius of Maximum Winds: 25 nm [45 km]
Dvorak Intensity Code: T4.0/4.0/D1.0/24HRS STT:D0.5/6HRS
Pressure of outermost isobar: 1006 hPa
Radius of outermost closed isobar: 350 nm [650 km]
Storm Depth: Deep
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+12: 07/1800: 14.9S 91.6E: 050 [095]: 060 [110]: 983
+24: 08/0600: 16.0S 94.1E: 080 [150]: 065 [120]: 981
+36: 08/1800: 17.3S 96.7E: 110 [210]: 050 [095]: 991
+48: 09/0600: 18.5S 98.7E: 145 [270]: 040 [075]: 996
+60: 09/1800: 19.4S 100.2E: 190 [355]: 030 [055]: 1001
+72: 10/0600: 20.1S 101.0E: 240 [445]: 030 [055]: 1001
REMARKS:
Tropical Cyclone Alenga has been located by visible and microwave imagery near
90E.
Intensity of 55 knots based on CI of 4.0 from a wrap of 1.1. The system is
currently in low shear ahead of a trough that will increase shear during
Thursday and Friday. Sea surface temperatures are currently favourable but
become less so as the system approaches 18S. The intensity is expected to be
maintained or slowly increase during the next 12 to 24 hours before the system
weakens, expected to fall below TC intensity as the system gets to 100E later on
Friday.
The motion of the system is expected to continue to be east to southeast over
the next few days under the influence of NW steering due to the mid latitude
trough.

Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 07/1300 UTC by Perth TCWC.

[Chacor]

Fairly significant difference between Réunion and Perth! From a MTS to an STS-equivalent just by crossing 90°E? I don't think so!

[Chacor]

Holy crap, Alenga's got an eye!