SIO : SUBTROPICAL DEPRESSION JOEL (98S)

[HURAKAN]

ZCZC 047
WTIO30 FMEE 271224
RSMC / TROPICAL CYCLONE CENTRE / LA REUNION
TROPICAL CYCLONE TECHNICAL BULLETIN (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER : 6/16/20092010
1.A SUBTROPICAL DEPRESSION 16 (JOEL)
2.A POSITION 2010/05/27 AT 1200 UTC :
WITHIN 20 NM RADIUS OF POINT 26.1S / 45.2E
(TWENTY SIX DECIMAL ONE DEGREES SOUTH AND FORTY FIVE DECIMAL TWO
DEGREES
EAST)
MOVEMENT : EAST-SOUTH-EAST 4 KT
3.A DVORAK ANALYSIS : /
4.A CENTRAL PRESSURE : 1000 HPA
5.A MAX AVERAGE WIND SPEED (10 MN) : 50 KT
RADIUS OF MAXIMUM WINDS (RMW) : 20 KM
6.A EXTENSION OF WINDS BY QUADRANTS (KM):
30 KT NE: 080 SE: 090 SO: 090 NO: 080
50 KT NE: 020 SE: 020 SO: 020 NO: 020
7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1013 HPA / 500 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM
1.B FORECASTS:
12H: 2010/05/28 00 UTC: 26.5S/45.9E, MAX WIND=040KT, SUBTROPICAL.
24H: 2010/05/28 12 UTC: 27.2S/46.1E, MAX WIND=030KT, SUBTROPICAL.
36H: 2010/05/29 00 UTC: 29.4S/47.5E, MAX WIND=025KT, DISSIPATING.
48H: 2010/05/29 12 UTC: 31.4S/49.3E, MAX WIND=025KT, DISSIPATING.
2.B OTHER INFORMATIONS:
EYE IS STILL VISIBLE DESPITE THE WEST-NOTHWESTERLY VERTICAL WINDSHEAR
CONSTRAINT.
METEOSAT7 SATELLITE IMAGERY SHOWS NOW A WINDSHEAR CIRRUS ARCH.
PHASE DIAGRAM DON'T SUSGEST THAT THIS LOW HAS BECAME TROPICAL, DVORAK
ANALISYS IS THEREFORE NOT SUITABLE FOR INTENSITY ESTIMATION.
0640Z ASCAT SWATH ALLOWS CALIBRATING WINDS EXTENSION BUT NOT WINDS
NEAR
THE CENTER.
PRESSURE OF THE SYSTEM IS HIGH DUE TO THE SMALL SIZE OF THE SYSTEM
AND
HIGH ENVIRONMENTAL PRESSURES.
UNDERGOING AN INCREASING VERTICAL WINDSHEAR (ROTATING SOUTHWESTERLY)
,
THE SYSTEM IS EXPECTED TO WEAKEN QUITE RAPIDLY DUE TO ITS SMALL
SIZE.
IT IS FORECAST TO TRACK SLOWLY EAST-SOUTHEASTWARDS DURING THE NEXT 12
HOURS,UNDER THE STEERING INFLUENCE OF THE MID LEVEL RIDGE LOCATED
OVER
THE NORTHERN PART OF MADAGASCAR , THEN SOUTHEASTWARDS AS A RIDGE HAS
REBUILDED EASTH OF THE SYSTEM.=
NNNN

[HURAKAN]

Still looks very well-organized

[HURAKAN]

Still looking good

[KWT]

Yep the system has held very well, I'd love to see a long term loop of this system actually!

That being said waters temps really do drop off further south and I can't imagine the system surviving much longer.

[HURAKAN]

27/2030 UTC 26.4S 46.3E T3.5/3.5 JOEL -- Southwest Indian

55 knots

[HURAKAN]

ZCZC 628
WTIO30 FMEE 280013
RSMC / TROPICAL CYCLONE CENTRE / LA REUNION
TROPICAL CYCLONE TECHNICAL BULLETIN (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER : 8/16/20092010
1.A SUBTROPICAL DEPRESSION 16 (JOEL)
2.A POSITION 2010/05/28 AT 0000 UTC :
WITHIN 30 NM RADIUS OF POINT 26.7S / 46.3E
(TWENTY SIX DECIMAL SEVEN DEGREES SOUTH AND FORTY SIX DECIMAL THREE
DEGREES EAST)
MOVEMENT : SOUTH-EAST 6 KT
3.A DVORAK ANALYSIS : /
4.A CENTRAL PRESSURE : 1002 HPA
5.A MAX AVERAGE WIND SPEED (10 MN) : 40 KT
RADIUS OF MAXIMUM WINDS (RMW) : 20 KM
6.A EXTENSION OF WINDS BY QUADRANTS (KM):
30 KT NE: 060 SE: 120 SO: 120 NO: 060
7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1013 HPA / 300 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM
1.B FORECASTS:
12H: 2010/05/28 12 UTC: 27.5S/46.9E, MAX WIND=035KT, SUBTROPICAL.
24H: 2010/05/29 00 UTC: 28.8S/47.5E, MAX WIND=025KT, DISSIPATING.
2.B OTHER INFORMATIONS:
EYE IS STILL VISIBLE DESPITE THE WESTERLY VERTICAL WINDSHEAR
CONSTRAINT.
ECMWF NWP MODEL ANALYSES STRONG WESTERLY WINDS IN THE UPPER LEVEL
ONLY
ABOVE THE LEVEL 250 HPA AND THE WINDSHEAR CONSTRAINT REMAINS
RELATIVELY
WEAK BELOW.
THIS ENVIRONMENT ALLOWS JOEL TO RESIST DESPITE AN OBVIOUS TILD
BETWEEN
UPPER AND LOW LEVELS.
ECMWF AND ALADIN NWP MODELS SUGGEST THAT STRONGEST WINDS SHOULD
PROGRESSIVELY EXTEND TOWARDS THE MID LEVEL ON AND AFTER 28/0600Z OR
28/1200Z AND SOULD THEREFORE INDUCE RAPID WEAKNING OF THE SYSTEM.
THIS FORECAST MAINTAINS THEREFORE INTENSITY STRONGEST WITHIN THE NEXT
12H
TO 18H THAN THE PREVIOUS ONE.
PHASE DIAGRAMS DON'T SUSGEST THAT THIS LOW HAS BECAME TROPICAL,
DVORAK
ANALISYS IS THEREFORE NOT SUITABLE FOR INTENSITY ESTIMATION.
27/1903Z ASCAT SWATH ALLOWS CALIBRATING WINDS EXTENSION BUT NOT WINDS
NEAR THE CENTER.
PRESSURE OF THE SYSTEM IS HIGH DUE TO THE SMALL SIZE OF THE SYSTEM
AND
HIGH ENVIRONMENTAL PRESSURES.
JOEL IS EXPECTED TO KEEP ON TRACKING SOUTHEASTWARDS THEN
SOUTH-SOUTHEASTWARDS TOWARDS A POLAR TROUGH FORECASTED TO SHIFT IN
ITS
SOUTH.
IT SHOULD DISSIPATE WITHIN IT ON AND AFTER TAU 24 TO TAU 36.=
NNNN

[HURAKAN]

28/0830 UTC 26.9S 46.8E T3.5/3.5 JOEL -- Southwest Indian

pretty impressive

[HURAKAN]

ZCZC 607
WTIO30 FMEE 281229
RSMC / TROPICAL CYCLONE CENTRE / LA REUNION
TROPICAL CYCLONE TECHNICAL BULLETIN (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER : 10/16/20092010
1.A SUBTROPICAL DEPRESSION 16 (JOEL)
2.A POSITION 2010/05/28 AT 1200 UTC :
WITHIN 20 NM RADIUS OF POINT 26.8S / 46.9E
(TWENTY SIX DECIMAL EIGHT DEGREES SOUTH AND FORTY SIX DECIMAL NINE
DEGREES EAST)
MOVEMENT : QUASI-STATIONARY
3.A DVORAK ANALYSIS : /
4.A CENTRAL PRESSURE : 1000 HPA
5.A MAX AVERAGE WIND SPEED (10 MN) : 45 KT
RADIUS OF MAXIMUM WINDS (RMW) : 15 KM
6.A EXTENSION OF WINDS BY QUADRANTS (KM):
30 KT NE: 110 SE: 165 SO: 070 NO: 085
7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1012 HPA / 300 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM
1.B FORECASTS:
12H: 2010/05/29 00 UTC: 28.5S/46.9E, MAX WIND=030KT, SUBTROPICAL.
24H: 2010/05/29 12 UTC: 31.8S/47.8E, MAX WIND=025KT, DISSIPATING.
36H: 2010/05/30 00 UTC: 38.6S/52.4E, MAX WIND=025KT, DISSIPATING.
2.B OTHER INFORMATIONS:
JOEL BECOMES A VERY SMALL SYSTEM (AVERAGE EXTENSION OF NEAR GALE
FORCE
WIND AT ABOUT 1 DEGREE), A NICE EXAMPLE OF A SUBTROPICAL MIDGET.
LATEST AVAILABLE ELEMENTS TO ANALYSE JOEL INTENSITY GIVE WINDS AT
35-40
KT AND 50 KT FROM RESPECTIVELY PGTW (HEBERT POTEAT TECHNIQUE USED FOR
SUBTROPICAL SYSTEM) AND SAB (DVORAK TECHNIQUE). PARTIAL ASCAT SWATH
FROM
0619Z SUGGEST BELIEVABLE 40-45 KT WINDS.
TRMM PASS AT 0935Z STILL SHOWS A WELL DEFINED CENTRAL CORE ALTHOUGHT
THE
EYE PATTERN SEEMS TO DETERIORATE SOMEWHAT.
ON THE BASIS OF PREVIOUSLY EXPOSED ELEMENTS PLUS THE FACT THAT
OVERALL
PATTERN OVER LATEST VISIBLE IMAGERY IS BETTER THAN 24 HOURS AGO,
SYSTEM
IS UPGRADED TO 45 KT FOR THIS PACKAGE.
WATER VAPOR IMAGERY STILL SHOW THAT JOEL IS LOCATED WITHIN AN UPPER
LEVEL
TROUGH ASSOCIATED WITH A LOWER TROPOPAUSE THAN USUAL (NEAR 250-300
HPA)
ECMWF WINDS FIELDS SHOW THAT WINDS AT THIS LEVEL STILL ALLOW WEAK TO
MODERATE WIND SHEAR FOR THE SYSTEM. AS THE UPPER LEVEL TROUGH WILL
PROGRESSIVELY MOVE EASTWARDS AND JOEL MOVES ALONG A SOUTHWARDS TRACK
ON
THE WESTERN EDGE OF THE SUBTROPICAL RIDGE, SOUTHWESTERLY SHEAR SHOULD
STRENGHEN AND WEAKEN T
HE SYSTEM.
AT TAU 36 HRS, JOEL SHOULD DISSIPATE WITHIN A MID LAT TROUGH.=
NNNN

[HURAKAN]

keeps fighting

[HURAKAN]

ZCZC 351
WTIO30 FMEE 281822
RSMC / TROPICAL CYCLONE CENTRE / LA REUNION
TROPICAL CYCLONE TECHNICAL BULLETIN (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER : 11/16/20092010
1.A SUBTROPICAL DEPRESSION 16 (JOEL)
2.A POSITION 2010/05/28 AT 1800 UTC :
WITHIN 20 NM RADIUS OF POINT 27.0S / 46.8E
(TWENTY SEVEN DECIMAL ZERO DEGREES SOUTH AND FORTY SIX DECIMAL EIGHT
DEGREES EAST)
MOVEMENT : SOUTH 3 KT
3.A DVORAK ANALYSIS : /
4.A CENTRAL PRESSURE : 1003 HPA
5.A MAX AVERAGE WIND SPEED (10 MN) : 40 KT
RADIUS OF MAXIMUM WINDS (RMW) : 23 KM
6.A EXTENSION OF WINDS BY QUADRANTS (KM):
30 KT NE: 110 SE: 110 SO: 055 NO: 055
7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1013 HPA / 400 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM
1.B FORECASTS:
12H: 2010/05/29 06 UTC: 30.0S/46.9E, MAX WIND=030KT, SUBTROPICAL.
24H: 2010/05/29 18 UTC: 35.9S/49.6E, MAX WIND=025KT, DISSIPATING.
2.B OTHER INFORMATIONS:
WHEELS TURN ON TO THE OTHER SIDE FOR JOEL ... AS EXPECTED, THE UPPER
LEVEL TROUGH MOVE EASTWARDS AND SHEAR IS NOW BULDIND BACK OVER THE
SMALL
CIRCULATION OF THE SYSTEM. LATEST SATELLITE AND MW IMAGERY SHOW A
CLEAR
SHEAR PATTERN WITH AN LLCC PARTLY EXPOSED ON THE WESTSOUTHWESTERN
EDGE OF
MAIN CONVECT
ION (CF. 1618Z SSMIS)
ON THE BASIS OF CLEAR CUT WEAKENING SIGNALS THAT HAS APPEARED JUST
AFTER
12Z, INTENSITY IS LOWERED TO 40 KT ALTHOUGHT IT SEEMS A LITTLE BIT
GENEROUS (35-40 KT MAX WINDS LOCATED WITHIN THE EASTERN SEMI-CIRCLE)
JOEL CONTINU TO MOVE LITTLE BUT LATEST FIX SUGGEST THAT A SOUTHWARDS
DRIFT MAY HAVE BEGUN. IT SHOULD GRADUALLY ACCELERATED AS SYSTEM
SHOULD BE
ABSORBED BY A MID-LAT TROUGH WITHIN THE NEXT 24 HOURS.=
NNNN

[HURAKAN]

Latest & last!

[HURAKAN]

ZCZC 305
WTIO30 FMEE 290053
RSMC / TROPICAL CYCLONE CENTRE / LA REUNION
TROPICAL CYCLONE TECHNICAL BULLETIN (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER : 12/16/20092010
1.A SUBTROPICAL DEPRESSION 16 (JOEL)
2.A POSITION 2010/05/29 AT 0000 UTC :
WITHIN 20 NM RADIUS OF POINT 28.0S / 46.6E
(TWENTY EIGHT DECIMAL ZERO DEGREES SOUTH AND FORTY SIX DECIMAL SIX
DEGREES EAST)
MOVEMENT : SOUTH 8 KT
3.A DVORAK ANALYSIS : /
4.A CENTRAL PRESSURE : 1008 HPA
5.A MAX AVERAGE WIND SPEED (10 MN) : 30 KT
RADIUS OF MAXIMUM WINDS (RMW) : NIL
6.A EXTENSION OF WINDS BY QUADRANTS (KM):
30 KT NE: 055 SE: 055 SO: NO:
7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1013 HPA / 350 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM
1.B FORECASTS:
12H: 2010/05/29 12 UTC: 30.7S/48.1E, MAX WIND=025KT, DISSIPATED.
2.B OTHER INFORMATIONS:
WHEELS TURN ON TO THE OTHER SIDE FOR JOEL ... AS EXPECTED, THE UPPER
LEVEL TROUGH MOVE EASTWARDS AND SHEAR IS NOW BULDIND BACK OVER THE
SMALL
CIRCULATION OF THE SYSTEM. LATEST IR SATELLITE SHOW A FULLY EXPOSED
VORTEX SINCE 20Z.
ON THE BASIS OF ITS SMALL SIZE, INTENSITY IS STRONGLY LOWERED TO 30
KT
(RESIDUAL WITHIN THE EASTERN SEMI-CIRCLE)
JOEL HAS ACCELERATED SOUTHWARDS AND SHOULD CONTINU ON THIS TREND
TOWARDS
A MID-LAT TROUGH THAT WILL ABSORB IT LATER TODAY ....
LAST ADVISORY UNLESS REINTENSIFICATION=
NNNN

[KWT]

Got to admit Joel lasted quite some time, reminded me a little of the way Epsilon kept on going despite being forecasted to weaken every time.

These little cool SST (relative of course!) systems seem to have a habit of holding on longer then expected don't they!

[DanieleItalyRm]

It sure is tiny. Honestly it looks ALOT like some of the systems we've had in the Mediterranean and NE Atlantic. What are the water temperatures like down on the southwest coast of Madagascar?

I absolutely agree. It a tropical cyclone, no subtropical. It looks ALOT like some of the systems we've had in the Mediterranean and NE Atlantic.
It become in tropical cyclone from tropical transition and result is tiny (many Mediterranean tropical cyclones or tropical cyclones Karl'80, Vince'05, Grace'09 ecc).
The process known as "tropical transition" involves the usually slow development of an extratropically cold core vortex into a tropical cyclone.

example: two Mediterranean TC and two NE Atlantic TC