SPAC: IAN - Tropical Cyclone

[jaguarjace]

15.3S 175.7W

[hurricanes1234]

I wonder if this will end up like 97P, or form into something.

[jaguarjace]

WTPS21 PHNC 050230
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
130 NM EITHER SIDE OF A LINE FROM 17.8S 176.0W TO 22.4S 175.0W
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
050200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 18.4S
176.0W. THE SYSTEM IS MOVING SOUTHWARD AT 09 KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 17.6S
175.3W, IS NOW LOCATED NEAR 18.4S 176.0W, APPROXIMATELY 390 NM
SOUTHWEST OF PAGO PAGO, AMERICAN SAMOA. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY (MSI) DEPICTS A PERSISTENT AREA OF DEEP CONVECTION
OBSCURING A PARTIALLY-EXPOSED, LOW-LEVEL CIRCULATION CENTER (LLCC).
A 042135Z METOP-B 89 GHZ MICROWAVE IMAGE REVEALS A SLOWLY-
CONSOLIDATING SYSTEM WITH CURVED BANDING WRAPPING INTO THE LLCC. A
042040Z ASCAT IMAGE DEPICTS A WELL-DEFINED CIRCULATION WITH 25 TO 30
KNOT WINDS OVER THE NORTHERN SEMI-CIRCLE AND 15 TO 20 KNOT WINDS
OVER THE SOUTHERN SEMICIRCLE. UPPER-LEVEL ANALYSIS INDICATES A
MARGINALLY FAVORABLE ENVIRONMENT WITH LOW TO MODERATE (10 TO 15
KNOTS) VERTICAL WIND SHEAR AND FAIR OUTFLOW. 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 IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
060230Z.//
NNNN

[stormkite]

Tropical Disturbance Summary For area Equator to 25S, 160E to 120W
ISSUED FROM RSMC NADI Jan 05/0902 UTC 2014 UTC.

TROPICAL DEPRESSION TD07F CENTRE [1000HPA] ANALYSED NEAR 19.0S 176.1W
AT 050600 UTC. TD07F MOVING SOUTH AT 05 KNOTS. POSITION POOR BASED ON
MTSAT VIS/IR IMAGERY AND PERIPHERAL SURFACE OBSERVATIONS. SST AROUND
29 DEGREES CELCIUS.

ORGANISATION HAS SLIGHTLY IMPROVED IN LAST 24 HOURS. CONVECTION
REMAINS PERSISTANT PAST 24 HOURS NEAR LLCC. SYSTEM LIES UNDER AN
UPPER LEVEL RIDGE IN A LOW SHEARED ENVIRONMENT. CYCLONIC CIRCULATION
EXTENDS UPTO 500HPA.

GLOBAL MODELS HAVE PICKED UP THE SYSTEM AND MOVE IT SOUTHWARD WITH
SLIGHT INTENSIFICATION.

POTENTIAL FOR THIS SYSTEM TO DEVELOP INTO A TROPICAL CYCLONE IN THE
NEXT 24 TO 48 HOURS IS MODERATE.

NO OTHER SIGNIFICANT TROPICAL DISTURBANCE ANALYSED OR FORECAST IN THE
AREA.

[Grifforzer]

From the Gale Warning page on Fiji Meteorological Department..

Expect clockwise wind up to 35 knots within 60-90 NM away from the center in the sector from northwest through north to northeast

From the Tropical Disturbance Advisory page..

Statement #2 released at 18:00 PM UTC..

At 6:00 AM FST, Tropical Depression 07F (1000 hPa) located at 18.8S 175.8W has 10 minute sustained winds of 30 knots. Position poor based on hourly multispectral enhanced infrared imagery and peripheral surface reports. The depression is reported as moving slowly.

Overall organization has improved in the past 24 hours and convection remains persistent. System lies in a weak to moderate sheared environment under an upper ridge. Outflow good to the east but restricted elsewhere. The system is steered southeastward by a northwest-southwest oriented mid level ridge situated to the east of the system.

Dvorak analysis based on a 0.5 wrap yielding DT=2.5, PT=2.5, and MET=2.5. Final Dvorak intensity based on DT. Sea surface temperature is around 29C.

Dvorak Intensity: T2.5/2.5/D1.0/24 HRS

Most models agree on a southeastward movement then recurving westward with gradual intensification.

12 HRS: 19.1S 175.5W - 30 knots
24 HRS: 19.1S 175.7W - 35 knots
48 HRS: 18.6S 176.8W - 40 knots

[jaguarjace]

RSMC Nadi Tropical Cyclone Warning Centre

TROPICAL CYCLONE FORECAST TRACK MAP
Tropical Cyclone IAN
Issued at 2345 UTC Sunday 5 January 2014.



ORGANISATION HAS IMPROVED SIGNIFICANTLY PAST 24 HOURS. CONVECTION HAS
INCREASED WITH PRIMARY BANDS TRYING TO WRAP AROUND THE LLCC. SYSTEM
LIES IN A LOW SHEARED ENVIRONMENT UNDER AN UPPER RIDGE. OUTFLOW GOOD
THE THE EAST BUT RESTRICTED ELSEWHERE. IAN IS STEERED SOUTHEASTWARDS
ALONG THE WESTERN PERPHERY OF A SUBTROPICAL RIDGE SITUATED TO THE
EAST OF THE SYSTEM. DVORAK ANALYSIS BASED ON 0.65 WRAP YIELDING DT OF
3.0, MET AND PT AGREE. FT BASED ON DT THUS, T3.0/3.0/D1.0/24HRS. SST
AROUND 29 DEGREES CELCIUS.

MOST MODELS AGREE ON A SOUTHEASTWARD MOVEMENT THEN RECURVING
WESTWARDS WITH GRADUAL INTENSIFICATION.

http://www.met.gov.fj/aifs_prods/20032.txt

[stormkite]

TROPICAL CYCLONE ADVISORY NUMBER FOUR FOR TONGA ON TROPICAL CYCLONE IAN
ISSUED FROM THE FUA'AMOTU TROPICAL CYCLONE WARNING CENTRE AT 7:00PM MONDAY (6/01/2014).

TROPICAL CYCLONE ALERT

A GALE ALERT REMAINS IN FORCE FOR VAVA'U AND HA'APAI GROUPS.

A STRONG WIND WARNING REMAINS IN FORCE FOR HA'APAI AND VAVA'U.

A HEAVY RAIN ADVISORY REMAINS IN FORCE FOR ALL OF TONGA

TROPICAL CYCLONE IAN CAT 1 WAS LOCATED NEAR 18 DECIMAL 6 SOUTH 175 DECIMAL
7 WEST OR ABOUT 180KM WEST OF VAVA'U OR ABOUT 195KM NORTHWEST OF LIFUKA
AT 4PM THIS AFTERNOON.TROPICAL CYCLONE IAN HAS ESTIMATED WINDS
OF 40KT NEAR ITS CENTRE AND IS CURRENTLY SLOW MOVING.THE SYSTEM IS SLOWLY
INTENSIFYING.

ON THIS TRACK,THE CYCLONE CONTINUES TO INTENSIFY, IT MAY BRING
DAMAGING GALE FORCE WINDS OVER VAVA'U AND HA'APAI GROUPS IN THE NEXT 24
TO 48HRS.

FORECAST TO MIDNIGHT TOMORROW FOR TONGA

FOR VAVA'U AND HA'APAI GROUP:
MODERATE TO FRESH NORTH TO NORTHWEST WINDS BECOMING STRONG AND GUSTY.
RAIN DEVELOPING, BECOMING HEAVY AT TIMES.

FOR THE REST OF TONGA:
LIGHT TO MODERATE NORTHWEST WINDS ABOUT THE NIUAS. MOSTLY CLOUDY WITH
OCCASIONAL SHOWERS WITH SOME HEAVY FALLS EXPECTED. FOR TONGATAPU AND EUA,
LIGHT TO MODERATE EAST WINDS BECOMING MODERATE TO FRESH NORTH TO NORTH
EAST WINDS. MOSTLY CLOUDY WITH OCCASIONAL SHOWERS HEAVY AT TIMES.

OUTLOOK FOR WEDNESDAY
FOR VAVA'U AND HA'APAI GROUP:
FRESH TO STRONG NORTH TO NORTHWEST WINDS AND MAY INCREASE FURTHER TO
DAMAGING GALE FORCE. RAIN HEAVY AT TIMES WITH FLOODING INCLUDING SEAS
FLOODING POSSIBLE.

FOR THE REST OF TONGA:
LIGHT TO MODERATE NORTHWEST WINDS ABOUT THE NIUAS. MOSTLY CLOUDY WITH
OCCASIONAL SHOWERS WITH SOME HEAVY FALLS EXPECTED. FOR TONGATAPU AND EUA,
MODERATE TO FRESH NORTH TO NORTHEAST WINDS GUSTY AT TIMES. MOSTLY CLOUDY
WITH RAIN HEAVY AT TIMES.

TEMPERATURE FORECAST FOR NUKU'ALOFA:
MAX: 30 DEGREES CELSIUS TOMORROW.
MIN: 24 DEGREES CELSIUS TONIGHT.

MARINE WEATHER BULLETIN:

FORECAST TO MIDNIGHT TOMORROW FOR TONGA

A GALE ALERT REMAINS IN FORCE FOR vAVA'U AND HAAPAI WATERS.

A STRONG WIND WARNING REMAINS IN FORCE VAVA'U AND HA'APAI WATERS.

FOR VAVA'U AND HA'APAI WATERS
NORTH TO NORTHWEST WINDS 20 TO 25 KNOTS WITH GUSTS 30-35KNOTS.SEAS
BECOMING VERY ROUGH WITH HEAVY NORTHWESTERLY SWELLS.
POOR VISIBILITY IN AREA OF HEAVY RAINS.

FOR THE REST OF TONGA WATERS
NORTHWEST WINDS ABOUT THE NIUAS 15-20KTS. MODERATE TO ROUGH SEAS.
ELSEWHERE EAST WINDS 15-20KTS TURNING NORTH TO NORTHEAST AND UP TO
25KTS AT TIMES.SEAS BECOMING ROUGH.

OUTLOOK FOR WEDNESDAY
FOR VAVA'U AND HA'APAI WATERS
NORTH TO NORTHWEST WINDS 20 TO 25 KNOTS WITH GUSTS 30-35KNOTS POSSIBLY
INCREASING TO 30-35KTS GUSTING TO 40 TO 45KTS.SEAS VERY ROUGH WITH
HEAVY NORTHWESTERLY SWELLS. POOR VISIBILITY IN AREA OF HEAVY RAINS.

FOR THE REST OF TONGA WATERS
NORTHWEST WINDS ABOUT THE NIUAS 15-20KTS. MODERATE TO ROUGH SEAS.
ELSEWHERE NORTH TO NORTHEAST 15-20KTS AND UP TO 25KTS AT TIMES. ROUGH
SEAS.

TIDE PREDICTIONS:
HIGH TIDE : 11:45PM
LOW TIDE : 06:02AM TOMORROW MORNING (07/01/20134)

THE MEAN SEA LEVEL PRESSURE RECORDED AT FUA'AMOTU AT 7:00PM THIS AFTERNOON
WAS 1004.5MB

THE NEXT SPECIAL WEATHER BULLETINE FOR TONGA ON TROPICAL CYCLONE IAN
WILL BE AT 10PM TODAY OR EARLIER IF WARANTED.

FD:NO/SV/CRS:

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Will get interesting if it follows this model.

[hurricanes1234]

Does not look good in my opinion. Banding is poor, convection not very organised, and has a bit of a sheared/starved appearance. JTWC has left it at 35 knots, as it has not really changed since then. It's SPAC after all.

The above is not professional information of any type, just my amateur opinion. Do not use it as such!

[stormkite]

Does not look good in my opinion. Banding is poor, convection not very organised, and has a bit of a sheared/starved appearance. JTWC has left it at 35 knots, as it has not really changed since then. It's SPAC after all.

The above is not professional information of any type, just my amateur opinion. Do not use it as such!

Off topic It's SPAC after all. ?

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Back to Topic

IMO Ian will intensify over the the next four days to be a 70-80 knot system.


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

[dexterlabio]

Well, the premise of the SHem cyclone season this year is way more interesting than EPAC and Atlantic hurricane season last year. IMO. It's just that Ian is in the wrong place for it to become a more potent cyclone.

[stormkite]

Well, the premise of the SHem cyclone season this year is way more interesting than EPAC and Atlantic hurricane season last year. IMO. It's just that Ian is in the wrong place for it to become a more potent cyclone.

It's not uncommon for SPAC systems to spin up loop around the islands turn back head west and intensify then head poleward. See how this pans out over the next 4-5 days.


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 product

[euro6208]

REMARKS:
070900Z POSITION NEAR 17.7S 176.1W.
TROPICAL CYCLONE 07P (IAN), LOCATED APPROXIMATELY 314 NM EAST OF
SUVA, FIJI, HAS TRACKED NORTHWARD AT 05 KNOTS OVER THE PAST SIX
HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS THERE HAS BEEN
LITTLE CHANGE IN THE STRUCTURAL ORGANIZATION OF THE SYSTEM OVER THE
PAST 12 HOURS. DVORAK ESTIMATES FROM PGTW AND KNES EVEN INDICATE A
SLIGHT WEAKENING TREND OVER THE PAST SIX HOURS. A RECENT 062307Z
OSCAT PASS INDICATED THE LOW LEVEL CIRCULATION CENTER (LLCC) REMAINS
SYMMETRIC WITH THE STRONGEST WINDS LOCATED ALONG THE NORTHERN HALF
OF THE CIRCULATION, RANGING FROM 30 TO 35 KNOTS. UPPER LEVEL
ANALYSIS INDICATES THE FAVORABLE EQUATORWARD OUTFLOW PERSISTS WITH
LOW VERTICAL WIND SHEAR (VWS) IN THE VICINITY OF THE LLCC. THE
ERRATIC TRACK FOR TC 07P WILL CONTINUE IN THE WEAK STEERING
ENVIRONMENT AS THE SYSTEM IS LOCATED BETWEEN A NEAR-EQUATORIAL RIDGE
(NER) TO THE NORTH AND A SUB-TROPICAL RIDGE (STR) TO THE SOUTH.
MODEL GUIDANCE INDICATES A MID-LATITUDE TROUGH LOCATED OVER
SOUTHEASTERN AUSTRALIA WILL TRACK OVER NEW ZEALAND AND CAUSE THE STR
TO MOVE EASTWARD. THE COMBINATION OF THE NER AND STR AROUND TAU 72
WILL CREATE AN IMPROVED STEERING ENVIRONMENT, TAKING THE TRACK TO
THE SOUTHEAST THROUGH THE END OF THE FORECAST PERIOD. IMPROVEMENT IN
THE UPPER LEVEL ENVIRONMENT IN THE NEAR TERM WILL ALLOW FOR A SLIGHT
INTENSIFICATION THROUGH TAU 72, BUT AS THE TROUGH APPROACHES,
INCREASING VWS WILL CAUSE THE STRENGTHENING TO ABATE, EVENTUALLY
LEADING TO A WEAKENING TREND. MODEL TRACKERS REMAIN IN POOR
AGREEMENT DUE TO THE WEAK STEERING ENVIRONMENT, BUT COME INTO BETTER
ALIGNMENT IN THE EXTENDED TAUS. OVERALL, THERE IS LOW CONFIDENCE IN
THE FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 070600Z IS 10
FEET. NEXT WARNINGS AT 072100Z AND 080900Z.//
NNNN

[stormkite]

2014JAN07 115200 3.1 992.6 47.0

[hurricanes1234]

Up to 45 knots. Looks much better than yesterday!

07P IAN 140107 1800 17.0S 176.7W SHEM 45 989

[stormkite]

Tropical Disturbance Summary For area Equator to 25S, 160E to 120W
ISSUED FROM RSMC NADI Jan 07/0847 UTC 2014 UTC.

TROPICAL CYCLONE IAN 07F CENTRE 995HPA WAS LOCATED NEAR 18.4S 176.4W
AT 070600 UTC. POSITION POOR BASED ON MTSAT VIS/IR IMAGERY WITH
ANIMATION AND PERIPHERAL SURFACE REPORTS. CYCLONE MOVING WEST AT
ABOUT 3 KNOTS.

FOR FURTHER INFORMATION OF TROPICAL CYCLONE IAN, REFER TO THE LATEST
TROPICAL DISTURBANCE ADVISORY ISSUED BY RSMC NADI.








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 product

[stormkite]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.5
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 08 JAN 2014 Time : 003200 UTC
Lat : 16:45:53 S Lon : 176:40:35 W


CI# /Pressure/ Vmax
3.5 / 987.9mb/ 55.0kt



Deep convention is now evident in the sat-pic and the system's banding appear's to be tightening up.


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

[hurricanes1234]

Up to 50 knots.

07P IAN 140108 0000 16.4S 176.7W SHEM 50 985

[stormkite]

[euro6208]

Up to 50 knots.

07P IAN 140108 0000 16.4S 176.7W SHEM 50 985

07P IAN 140108 1200 16.5S 177.0W SHEM 55 982

Ian still surprising us now up to 55 knots 1 min and forecast to strengthen to a category 2 cyclone!

REMARKS:
080900Z POSITION NEAR 16.7S 176.9W.
TROPICAL CYCLONE 07P (IAN), LOCATED APPROXIMATELY 275 NM EAST-
NORTHEAST OF SUVA, FIJI, HAS TRACKED NORTHWARD AT 02 KNOTS OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS THE
LOW LEVEL CIRCULATION CENTER (LLCC) REMAINS WELL ORGANIZED WITH
TIGHTLY CURVED BANDING CONVECTION WRAPPING INTO THE CENTER. DVORAK
ESTIMATES FROM PGTW, KNES, AND NFFN HAVE BEEN STEADY OVER THE PAST
SIX HOURS, BUT DUE TO THE SLIGHT INCREASE IN CENTRAL CONVECTION THE
INTENSITY HAS BEEN INCREASED TO 55 KNOTS. A RECENT 2358Z GCOM 36H
MICROWAVE IMAGE SHOWS A DEVELOPING EYE FEATURE, SUPPORTING THE
INCREASE IN INTENSITY. UPPER LEVEL ANALYSIS INDICATES THAT FAVORABLE
EQUATORWARD OUTFLOW PERSISTS WITH LOW VERTICAL WIND SHEAR (VWS) IN
THE VICINITY OF THE LLCC. ADDITIONALLY, ANIMATED WATER VAPOR IMAGERY
IS BEGINNING TO DEPICT THE DEVELOPMENT OF A POLEWARD OUTFLOW
CHANNEL. THE ERRATIC TRACK FOR TC 07P WILL CONTINUE DUE TO THE WEAK
STEERING ENVIRONMENT AS THE SYSTEM IS LOCATED BETWEEN A NEAR-
EQUATORIAL RIDGE (NER) TO THE NORTH AND A SUB-TROPICAL RIDGE (STR)
TO THE SOUTH. DYNAMIC MODEL GUIDANCE INDICATES A MID-LATITUDE TROUGH
LOCATED OVER SOUTHEASTERN AUSTRALIA WILL TRACK OVER NEW ZEALAND AND
CAUSE THE STR TO MOVE EASTWARD NEAR TAU 24. THE REORIENTATION OF THE
NER AND STR WILL RESULT IN AN IMPROVED STEERING ENVIRONMENT, TAKING
THE TRACK TO THE SOUTHEAST THROUGH THE END OF THE FORECAST PERIOD.
IMPROVEMENTS IN THE UPPER LEVEL ENVIRONMENT IN THE NEAR TERM WILL
ALLOW FOR INTENSIFICATION THROUGH TAU 72, BUT AS THE TROUGH
APPROACHES, INCREASING VWS WILL CAUSE A WEAKENING TREND TO BEGIN,
AND THE EVENTUAL START OF AN EXTRA-TROPICAL TRANSITION. MODEL
GUIDANCE HAS IMPROVED IN THE PAST 12 HOURS, BUT DUE TO THE CURRENTLY
WEAK STEERING ENVIRONMENT AND THE TIMING OF THE TURN TO THE
SOUTHEAST, THE CONFIDENCE IN THE FORECAST TRACK REMAINS LOW.MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 080600Z IS 14 FEET. NEXT WARNINGS AT
082100Z AND 090900Z.//
NNNN

[hurricanes1234]

Up to 60 knots and nearing cyclone strength (SSHS).

07P IAN 140108 1800 16.7S 176.8W SHEM 60 978