SIO: GAEL - Severe Tropical Storm - Discussion

[CrazyC83]

On its way to Very Intense Tropical Cyclone status?

[Crostorm]

[Crostorm]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 7.2.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 06 FEB 2009 Time : 233000 UTC
Lat : 19:32:08 S Lon : 51:47:10 E


CI# /Pressure/ Vmax
5.8 / 934.0mb/109.8kt


Final T# Adj T# Raw T#
(3hr avg)
5.8 6.3 6.6

Latitude bias adjustment to MSLP : +1.4mb

Estimated radius of max. wind based on IR : 28 km

Center Temp : +8.7C Cloud Region Temp : -73.3C

Scene Type : EYE

Positioning Method : RING/SPIRAL COMBINATION

Ocean Basin : INDIAN
Dvorak CI > MSLP Conversion Used : PACIFIC

Tno/CI Rules : Constraint Limits : 2.2T/6hr
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

****************************************************

[Crostorm]

415
WTIO30 FMEE 070023

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

0.A WARNING NUMBER : 21/8/20082009
1.A INTENSE TROPICAL CYCLONE 8 (GAEL)

2.A POSITION 2009/02/07 AT 0000 UTC :
19.5S / 51.8E
(NINETEEN DECIMAL FIVE DEGREES SOUTH AND FIFTY ONE DECIMAL EIGHT DEGREES
EAST)
MOVEMENT : SOUTH-WEST 3 KT

3.A DVORAK ANALYSIS : 5.5/5.5 /D 1.0/24 H
4.A CENTRAL PRESSURE : 941 HPA
5.A MAX AVERAGE WIND SPEED (10 MN) : 90 KT
RADIUS OF MAXIMUM WINDS (RMW) : 30 KM

6.A EXTENSION OF WINDS BY QUADRANTS (KM):
30 KT NE: 350 SE: 350 SO: 400 NO: 350
50 KT NE: 070 SE: 070 SO: 090 NO: 070

7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1007 HPA / 1000 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS:
12H: 2009/02/07 12 UTC: 21.0S/51.6E, MAX WIND=100KT , INTENSE TROP. CYCL.
..
24H: 2009/02/08 00 UTC: 22.2S/51.9E, MAX WIND=100KT , INTENSE TROP. CYCL.
..
36H: 2009/02/08 12 UTC: 23.9S/52.6E, MAX WIND=090KT , INTENSE TROP. CYCL.
..
48H: 2009/02/09 00 UTC: 26.1S/53.5E, MAX WIND=080KT , TROPICAL CYCLONE.
60H: 2009/02/09 12 UTC: 28.6S/55.3E, MAX WIND=070KT , BECOMING
EXTRATROPICAL.
72H: 2009/02/10 00 UTC: 30.5S/57.1E, MAX WIND=060KT , EXTRATROPICAL.

2.B OTHER INFORMATIONS:
T=CI=5.5

GAEL BENEFIT FROM A GOOD TRADE INFLOW THANKS TO THE SUBTROPICAL HIGH
PRESSURE IN ITS SOUTH-WEST. BUT THE MONSOON FLOW WAS CLEARELY CUT DURING
THE LAST HOURS : EROSION OF THE CDO IN THE NORTH-WESTERN QUADRANT (CF.
TRMM AT 17.41UTC AND AQUA AT 21.41UTC).

HOWEVER UPPER ENVIRONMENT IS BECOMING VERY FAVOURABLE WITH A GOOD
POLEWARD OUTFLOW WITHIN THE NEXT 12 HOURS WITH AN INTERACTION WITH THE
NORTHWESTERLY SUBTROPICAL JET LOCATED SOUTH OF MADAGASCAR. MAXIMAL
INTENSITY SHOULD BE REACH WITHIN THE NEXT HOURS BEFORE COOLER SST AND A
STRONGER NORTHWESTERLY V
ERTICAL WINDSHEAR STARTING SUNDAY NIGHT.

GAEL TRACKS UNDER THE STEERING FLOW OF AN UPPER LEVEL RIDGE PRESENT IN
THE SOUTHEAST OF THE SYSTEM. IT IS EXPECTED TO RECURVE ONCE MORE
PROGRESSIVELY TOWARDS THE SOUTH, THEN SOUTHSOUTHEASTWARDS SUNDAY.

[margiek]

JT increased to 120 kt current intensity at 07/0000Z.

* * * * * * * * * * * * *

Yesterday I saw this in the news and I wondered, "Who are these guys?" -- and believe me I don't mean it in the same sense that Redford and Newman did.

"Evergreen, CO, February 4, 2009 – The Swinden Group, through their Severe Weather Advisories, is advising interests and travelers to Madagascar to prepare for the arrival of Tropical Cyclone Gael which could have devastating effects to the island nation...Gael is expected to strike Madagascar in the vicinity of Toamasina (Tamatave), which is the nation’s chief port, on February 6th with winds in excess of 90 mph. Once overland, the cyclone is expected to weaken while tracking towards Antananarivo."

An unfortunate name for the company, given their level of forecast skill. I haven't been following the models but my understanding was that the concensus has consistently shown recurvature and that the outlier, NOGAPS, was recurving quicker than the others (at one time showing recurvature between Reunion and Mauritius).

They put out another press release today, which showed they must finally have got around to reading the forecasts by Reunion and JTWC from the last three days or so, but look at the conclusion:

"“The good news is that Gael is expected to make a left turn and not have a direct hit upon Madagascar. However the ‘X’ factor is when it will begin to make that turn...It is still too early to rule out if Tropical Cyclone Gael will be a glancing blow, direct hit, or a near miss all together for eastern Madagascar."



http://www.openpr.com/news/67167/The-Sw ... ascar.html

http://pr-usa.net/index.php?option=com_ ... &Itemid=31

[HURAKAN]

Monster Storm.

[CrazyC83]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 7.2.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 07 FEB 2009 Time : 013000 UTC
Lat : 19:35:44 S Lon : 51:40:04 E


CI# /Pressure/ Vmax
6.3 / 920.6mb/122.2kt


Final T# Adj T# Raw T#
(3hr avg)
6.3 6.4 6.6

Latitude bias adjustment to MSLP : +1.4mb

Estimated radius of max. wind based on IR : 26 km

Center Temp : +7.8C Cloud Region Temp : -72.9C

Scene Type : EYE

Positioning Method : RING/SPIRAL COMBINATION

Ocean Basin : INDIAN
Dvorak CI > MSLP Conversion Used : PACIFIC

Tno/CI Rules : Constraint Limits : 2.7T/12hr
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

[RattleMan]

Going for the gold?

WTXS31 PGTW 070300
1. TROPICAL CYCLONE 13S (GAEL) WARNING NR 010
02 ACTIVE TROPICAL CYCLONES IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
070000Z --- NEAR 19.5S 51.6E
MOVEMENT PAST SIX HOURS - 240 DEGREES AT 09 KTS
POSITION ACCURATE TO WITHIN 040 NM
POSITION BASED ON EYE FIXED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 120 KT, GUSTS 145 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 095 NM NORTHEAST QUADRANT
105 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 170 NM NORTHEAST QUADRANT
170 NM SOUTHEAST QUADRANT
140 NM SOUTHWEST QUADRANT
130 NM NORTHWEST QUADRANT
REPEAT POSIT: 19.5S 51.6E
---
FORECASTS:
12 HRS, VALID AT:
071200Z --- 20.6S 51.3E
MAX SUSTAINED WINDS - 125 KT, GUSTS 150 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 045 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
110 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 170 DEG/ 07 KTS
---
24 HRS, VALID AT:
080000Z --- 22.0S 51.6E
MAX SUSTAINED WINDS - 130 KT, GUSTS 160 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 050 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 065 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 105 NM NORTHEAST QUADRANT
115 NM SOUTHEAST QUADRANT
115 NM SOUTHWEST QUADRANT
105 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 150 DEG/ 07 KTS
---
36 HRS, VALID AT:
081200Z --- 23.3S 52.4E
MAX SUSTAINED WINDS - 135 KT, GUSTS 165 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 050 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 070 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 115 NM NORTHEAST QUADRANT
120 NM SOUTHEAST QUADRANT
120 NM SOUTHWEST QUADRANT
105 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 155 DEG/ 10 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
090000Z --- 25.1S 53.4E
MAX SUSTAINED WINDS - 140 KT, GUSTS 170 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 050 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 075 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
125 NM SOUTHEAST QUADRANT
125 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
---
REMARKS:
070300Z POSITION NEAR 19.8S 51.5E.
TROPICAL CYCLONE (TC) 13S (GAEL), LOCATED APPROXIMATELY 255 NM
WEST-NORTHWEST OF LA REUNION, HAS TRACKED WEST-SOUTHWESTWARD AT
09 KNOTS OVER THE PAST 06 HOURS. ANIMATED INFRARED SATELLITE
IMAGERY AND 6-HOUR DVORAK INTENSITY TREND INDICATE THAT THE
CYCLONE HAS INTENSIFIED TO NEAR 120 KNOTS. A RAGGED 25 NM EYE
IS ALSO VISIBLE IN INFRARED IMAGERY. THE SYSTEM IS PROJECTED
TO TRACK POLEWARD TOWARDS A WEAKNESS IN THE SUBTROPICAL STEERING
RIDGE WHILE INTENSIFYING. DUAL OUTFLOW CHANNELS WILL FACILITATE
THIS INTENSIFICATION. THE SYSTEM WILL REACH ITS MAXIMUM INTENSITY
NEAR TAU 24 AND WILL SLOWLY WEAKEN THEREAFTER. MAXIMUM SIGNIFICANT
WAVE HEIGHT AT 070000Z IS 25 FEET.NEXT WARNINGS AT 071500Z AND
080300Z. REFER TO TROPICAL CYCLONE 14S (FREDDY) WARNINGS (WTXS31
PGTW)
FOR TWELVE-HOURLY UPDATES.
//

[CrazyC83]

WHOA!!! What was the last Category 5 storm in the Southwest Indian Ocean?

07/0230 UTC 19.6S 51.7E T5.5/5.5 GAEL -- Southwest Indian - due to the variance, I think the intensity is a blend of all the data, my guess is 110 kt right now.

[HurricaneBill]

The last Category 5 cyclone in the Southwest Indian Ocean was Cyclone Bento in November 2004.

[HURAKAN]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 7.2.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 07 FEB 2009 Time : 043000 UTC
Lat : 19:43:38 S Lon : 51:47:21 E

CI# /Pressure/ Vmax
6.4 / 918.0mb/124.6kt

Final T# Adj T# Raw T#
(3hr avg)
6.3 6.2 6.2

Latitude bias adjustment to MSLP : +1.4mb

Estimated radius of max. wind based on IR : 19 km

Center Temp : -28.1C Cloud Region Temp : -74.3C

Scene Type : EYE

Positioning Method : RING/SPIRAL COMBINATION

Ocean Basin : INDIAN
Dvorak CI > MSLP Conversion Used : PACIFIC

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : ON
Rapid Dissipation Flag : OFF

****************************************************

[Chacor]

95 kt 938 hPa at 03z from MF.

[CrazyC83]

Eyewall not fully closed though on that picture - ERC underway?

[Ed Mahmoud]

Eyewall not fully closed though on that picture - ERC underway?

Dry air from Madagascar maybe?

[Ad Novoxium]

If I remember correctly, the current record for most intense Southwest Indian Ocean cyclone is 2004's Cyclone Gafilo: 895 mbar. However, it only had 1-min sustained winds of 160 mph, rather low.

[Crostorm]

898
WTIO30 FMEE 070623

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

0.A WARNING NUMBER : 22/8/20082009
1.A INTENSE TROPICAL CYCLONE 8 (GAEL)

2.A POSITION 2009/02/07 AT 0600 UTC :
20.0S / 51.7E
(TWENTY DECIMAL ZERO DEGREES SOUTH AND FIFTY ONE DECIMAL SEVEN DEGREES
EAST)
MOVEMENT : SOUTH 5 KT

3.A DVORAK ANALYSIS : 5.5/5.5 /D 0.5/24 H
4.A CENTRAL PRESSURE : 934 HPA
5.A MAX AVERAGE WIND SPEED (10 MN) : 95 KT
RADIUS OF MAXIMUM WINDS (RMW) : 40 KM

6.A EXTENSION OF WINDS BY QUADRANTS (KM):
30 KT NE: 350 SE: 350 SO: 400 NO: 350
50 KT NE: 070 SE: 070 SO: 090 NO: 070

7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1007 HPA / 1400 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS:
12H: 2009/02/07 18 UTC: 21.2S/52.1E, MAX WIND=100KT, INTENSE TROP. CYCL..
24H: 2009/02/08 06 UTC: 22.5S/52.5E, MAX WIND=100KT, INTENSE TROP. CYCL..
36H: 2009/02/08 18 UTC: 24.4S/53.3E, MAX WIND=090KT, INTENSE TROP. CYCL..
48H: 2009/02/09 06 UTC: 26.8S/54.5E, MAX WIND=080KT, TROPICAL CYCLONE.
60H: 2009/02/09 18 UTC: 28.8S/56.2E, MAX WIND=070KT, BECOMING
EXTRATROPICAL.
72H: 2009/02/10 06 UTC: 30.5S/57.6E, MAX WIND=060KT, EXTRATROPICAL.

2.B OTHER INFORMATIONS:
T=CI=5.5+
GAEL TAKES BENEFIT OF A GOOD TRADE LOW LEVEL INFLOW THANKS TO THE
SUBTROPICAL HIGH PRESSURES IN ITS SOUTH-WEST.
EQUATORWARD MONSOON FLOW IS LIMITED WESTWARD CUTTED BY MALAGASY AND
MICROWAVE IMAGERY (AMSU 0044Z AND 0135Z, SSMIS 0157Z) REVEALS A ERODED
EYEWALL IN THE WESTERN PART.
HOWEVER UPPER ENVIRONMENT IS BECOMING VERY FAVOURABLE WITH A GOOD
POLEWARD OUTFLOW WITHIN THE NEXT 12 HOURS WITH AN INTERACTION WITH THE
NORTHWESTERLY SUBTROPICAL JET LOCATED SOUTH OF MADAGASCAR.
PEAK OF INTENSITY SHOULD BE REACH WITHIN THE NEXT HOURS BEFORE COOLER SST
AND A STRONGER NORTHWESTERLY VERTICAL WINDS STARTING SUNDAY NIGHT.
IT DRIFTS ON A GLOBALLY SOUTHWARDS TRACK WITH SLOW MOTION.
IT IS EXPECTED TO SPEED UP SOUTH-SOUTHEASTWARDS IN A LESS AND LESS
FAVOURABLE ENVIRONMENT AND TO WEAK BEFORE BEGINNING ITS EXTRATROPICAL
TRANSITION.
NOTE : ACTUAL MOVE 180/08KT (5KT MENTIONNED IN THE BEGINNING OF THIS
ADVISORY IS AN AVERAGE FOR THE LAST 6 HOURS)


.

[Chacor]

Down to 90 kt 940 hPa at 09z.

[Chacor]

WTIO30 FMEE 071214

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

0.A WARNING NUMBER : 23/8/20082009
1.A INTENSE TROPICAL CYCLONE 8 (GAEL)

2.A POSITION 2009/02/07 AT 1200 UTC :
WITHIN 20 NM RADIUS OF POINT 20.6S / 51.8E
(TWENTY DECIMAL SIX DEGREES SOUTH AND FIFTY ONE DECIMAL EIGHT DEGREES
EAST)
MOVEMENT : SOUTH-SOUTH-EAST 7 KT

3.A DVORAK ANALYSIS : 5.0/5.5 /W 0.5/12 H
4.A CENTRAL PRESSURE : 940 HPA
5.A MAX AVERAGE WIND SPEED (10 MN) : 90 KT
RADIUS OF MAXIMUM WINDS (RMW) : 40 KM

6.A EXTENSION OF WINDS BY QUADRANTS (KM):
30 KT NE: 350 SE: 500 SO: 500 NO: 350
50 KT NE: 100 SE: 100 SO: 150 NO: 100

7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1007 HPA / 1200 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS:
12H: 2009/02/08 00 UTC: 21.8S/52.0E, MAX WIND=080KT, TROPICAL CYCLONE.
24H: 2009/02/08 12 UTC: 23.5S/52.6E, MAX WIND=070KT, TROPICAL CYCLONE.
36H: 2009/02/09 00 UTC: 25.8S/53.6E, MAX WIND=060KT, SEVERE TROP. STORM.
48H: 2009/02/09 12 UTC: 27.8S/55.1E, MAX WIND=060KT, BECOMING
EXTRATROPICAL.
60H: 2009/02/10 00 UTC: 29.9S/56.8E, MAX WIND=050KT, EXTRATROPICAL.
72H: 2009/02/10 12 UTC: 31.4S/57.6E, MAX WIND=050KT, EXTRATROPICAL.

2.B OTHER INFORMATIONS:
T=5.0 ET CI=5.5
GAEL THAS REACHED ITS PEAK OF INTENSITY AND BEGINS WEAKENING.
ENHANCED INFRARED PATTERN SHOWS A COLDER EYE AND MICROWAVE IMAGERY (AMSU
0622Z AND SSMIS 0157Z) REVEALS AN ERODED EYEWALL IN THE WESTERN PART.
IT GENERATES A SWELL FROM 3M TO 5M AVERAGE HIGH ON THE EASTERN MALAGASY
COASLINE AND THE ISLANDS OF LA REUNION AND MAURITIUS.
IT IS EXPECTED TO SPEED UP SOUTH-SOUTHEASTWARDS IN A LESS AND LESS
FAVOURABLE ENVIRONMENT AND TO WEAK BEFORE BEGINNING ITS EXTRATROPICAL
TRANSITION.
NOTE : ACTUAL MOVE 180/08KT (5KT MENTIONNED IN THE BEGINNING OF THIS
ADVISORY IS AN AVERAGE FOR THE LAST 6 HOURS)

[HURAKAN]

Down to 110 knots.

[cycloneye]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 7.2.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 07 FEB 2009 Time : 140000 UTC
Lat : 20:38:46 S Lon : 51:48:47 E


CI# /Pressure/ Vmax
6.0 / 928.1mb/115.0kt


Final T# Adj T# Raw T#
(3hr avg)
5.4 5.6 5.6

Latitude bias adjustment to MSLP : +1.1mb

Estimated radius of max. wind based on IR :N/A km

Center Temp : -40.3C Cloud Region Temp : -69.1C

Scene Type : EYE

Positioning Method : SPIRAL ANALYSIS

Ocean Basin : INDIAN
Dvorak CI > MSLP Conversion Used : PACIFIC

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : ON
Rapid Dissipation Flag : FLAG