SPO: JONI - Tropical Cyclone (20P)

[wyq614]

AN AREA OF CONVECTION HAS PERSISTED NEAR 18.7S 156.4W,
APPROXIMATELY 415 NM WEST OF TAHITI. RECENT ANIMATED MULTISPECTRAL
IMAGERY SHOWS A WELL-DEFINED LOW LEVEL CIRCULATION CENTER (LLCC)
WITH FORMATIVE CONVECTIVE BANDING WRAPPING INTO THE CENTER. THIS
LLCC IS CONFIRMED BY A 091715Z QUIKSCAT PASS SHOWING WINDS OF 25 TO
30 KNOTS NEAR THE CENTER. AN ANTI-CYLCONE ALOFT, AND WEAK UPPER-
LEVEL TROUGHING TO THE SOUTHEAST OF THE DISTURBANCE, ARE PROVIDING
AMPLE OUTFLOW FOR DEVELOPMENT. THE SYSTEM LIES IN A REGION OF WEAK
TO MODERATE VERTICAL WIND SHEAR, WARM SST (>26C) AND SIGNIFICANT
OCEAN HEAT CONTENT. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT
25 TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR
1001 MB. DUE TO THE FAVORABLE SURFACE CONDITON AS WELL AS GOOD
CONDITIONS ALOFT, THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT
TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS GOOD. SEE REF B (WTPS21
PGTW 100200) FOR FURTHER DETAILS.
(2) NO OTHER SUSPECT AREAS.
3. JUSTIFICATION FOR REISSUE: ADDED AREA IN PARA 2.B.(1) AS A GOOD.
FORECAST TEAM: BRAVO//

[Chacor]

[HurricaneBill]

Interesting. TCs near Tahiti usually happen during El Ninos. Although they can happen during La Ninas too.

[HURAKAN]

[HURAKAN]

[wyq614]

TROPICAL DEPRESSION 11F [1005HPA] CENTRE WAS LOCATED NEAR 20.3S
157.8E AT 102100 UTC, MOVING SOUTHWEST SLOWLY. POSITION FAIR BASED ON
GOES IR/VIS IMAGERY WITH ANIMATION, LATEST QUIKSCAT AND MICROWAVE
PASS. EXPECT CLOCKWISE WINDS 30 TO 40 KNOTS WITHIN 60 TO 150 NAUTICAL
MILES OF CENTRE IN THE SECTOR FROM NORTH THROUGH EAST TO SOUTHEAST.

11F LIES EMBEDDED IN AN ACTIVE SURFACE TROUGH. LLCC IS WEAKLY DEFINED
AT THIS STAGE WITH SURFACE PRESSURES OVER THE SOUTHERN COOKS ABOVE
1005 HPA. HOWEVER, THE MID-UPPER CYCLONIC CIRCULATION IS WELL
DEVELOPED WITH ENHANCED OUTFLOW TO THE NORTH AND EAST OF THE SYSTEM.
THE SYSTEM LIES UNDER A LOW SHEAR ENVIRONMENT AND CIMSS INDICATES 11F
IS MOVING INTO AREA OF DECREASING SHEAR. DVORAK ANALYSIS YIELDS 0.35
WRAP ON A POORLY DEFINED SPIRAL. DT=MET=2.0 AND PT=1.5. FT BASED ON
PT, LEADING TO T1.5/1.5/D0.5/24HRS. A DEVELOPING RIDGE OF HIGH
PRESSURE TO THE SOUTHEAST OF 11F IS ENHANCING THE PRESSURE GRADIENT
BETWEEN 11F AND ITSELF. MEANWHILE, AN UPPER TROUGH IS APPROACHING THE
SYSTEM FROM THE WEST. SST AROUND 28C. 11F IS BEING STEERED SOUTHWEST
BY A MID LEVEL RIDGE TO THE EAST AND EXPECTED TO CURVE SOUTHWARDS.
GLOBAL MODELS AGREE ON A SOUTHERLY TRACK WITH LITTLE INTENSIFICATION.
FURTHERMORE, CYCLONE PHASE EVOLUTION SUGGESTS THAT 11F IS NOT
ENTIRELY TROPICAL.

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

http://www.met.gov.fj/index.php?id=54&a ... =20032.txt

[HURAKAN]

[HURAKAN]

WTPS21 PGTW 100200
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE FORMATION ALERT REISSUED//
REF/A/MSG/NAVMARFCSTCEN PEARL HARBOR HI/100153ZMAR2009//
NARR/REF A IS A TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 19.8S 158.2W TO 25.6S 157.9W
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 IM-
AGERY AT 110130Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 20.8S 158.1W. THE SYSTEM IS MOVING SOUTHWARD AT 05 KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 18.7S
156.4W, IS NOW LOCATED NEAR 20.8S 158.1W, APPROXIMATELY 100 NM WEST
OF RAROTONGA. RECENT ANIMATED MULTISPECTRAL IMAGERY SHOWS FORMATIVE
CONVECTIVE BANDING BEGINNING TO WRAP INTO A LOOSELY-DEFINED LOW
LEVEL CIRCULATION CENTER (LLCC). THIS LLCC IS CONFIRMED BY A 101652Z
QUIKSCAT PASS SHOWING WINDS OF 25 TO 30 KNOTS NEAR THE CENTER WITH
EVEN STRONGER FLOW LOCATED 60 TO 80 NM NORTH OF THE SYSTEM CENTER.
AN ANTI-CYCLONE ALOFT IS PROVIDING AMPLE RADIAL OUTFLOW FOR
DEVELOPMENT, AND THE SYSTEM LIES IN A REGION OF WEAK VERTICAL WIND
SHEAR, WARM SST (>26C) AND SIGNIFICANT OCEAN HEAT CONTENT. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1002 MB. THE DISTURBANCE IS
TRACKING SOUTH ALONG THE NORTHWESTERN PERIPHERY OF A LOW- TO MID
LEVEL RIDGE LOCATED EAST-SOUTHEAST OF THE SYSTEM. ALTHOUGH
ORGANIZATION HAS IMPROVED OVER THE PAST 24 HOURS, THIS DISTURBANCE
REMAINS FAIRLY WEAK AND STILL LACKS SIGNIFICANT SURFACE DEVELOPMENT
NEAR THE LLCC TO WARRANT UPGRADE TO TROPICAL CYCLONE STATUS AT THIS
TIME. DUE TO THE IMPROVING SURFACE CONDITIONS AS WELL AS FAVORABLE
CONDITIONS ALOFT HOWEVER, THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS GOOD.
THIS SUPERSEDES REF A.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
120200Z.

[Chacor]

Now TC 20P.

[HURAKAN]

WTPS32 PGTW 110900
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ: TROPICAL CYCLONE 20P (TWENTY) WARNING NR 001
REF/A/NAVMARFCSTCEN/110152Z MAR 09//
AMPN/TROPICAL CYCLONE FORMATION ALERT//
1. TROPICAL CYCLONE 20P (TWENTY) WARNING NR 001
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
110600Z --- NEAR 21.2S 158.1W
MOVEMENT PAST SIX HOURS - 190 DEGREES AT 06 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
REPEAT POSIT: 21.2S 158.1W
---
FORECASTS:
12 HRS, VALID AT:
111800Z --- 23.0S 158.6W
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 180 DEG/ 09 KTS
---
24 HRS, VALID AT:
120600Z --- 24.7S 158.6W
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 36 HR POSIT: 175 DEG/ 09 KTS
---
36 HRS, VALID AT:
121800Z --- 26.5S 158.5W
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 48 HR POSIT: 170 DEG/ 09 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
130600Z --- 28.3S 158.2W
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
110900Z POSITION NEAR 21.6S 158.2W.
TROPICAL CYCLONE (TC) 20P, LOCATED APPROXIMATELY 95 NM EAST OF RARO-
TONGA, COOK ISLANDS, HAS TRACKED SOUTHWARD AT 06 KNOTS OVER THE PAST
06 HOURS. ANIMATED INFRARED SATELLITE IMAGERY AND AN 110513Z SSMI
IMAGE INDICATE A CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC)
WITH IMPROVED CONVECTIVE BANDING WRAPPING INTO THE SOUTHEAST QUADRANT
OF THE SYSTEM. THE SSMI 37 GHZ IMAGE SUPPORTS A DEVELOPING LLCC
WITH A MORE DEFINED CENTER. RECENT SCATTEROMETER, IN GENERAL, SHOWED
25-30 KNOT UNFLAGGED WINDS. HOWEVER, DVORAK ESTIMATES HAVE INCREASED
TO 30-35 KNOTS BASED ON THE IMPROVED STRUCTURE NEAR THE CENTER. THE
LLCC IS SITUATED UNDER AN UPPER-LEVEL ANTICYCLONE WITH GOOD POLEWARD
OUTFLOW ENHANCED BY A DEEP SHORTWAVE TROUGH WEST OF THE SYSTEM (ALONG
165W) AND AN ANTICYCLONE NEAR 28S 147W. THE SYSTEM IS TRACKING ALONG
THE WESTERN PERIPHERY OF A POLEWARD ORIENTED LOW-LEVEL SUBTROPICAL
RIDGE AND IS FORECAST TO CONTINUE TRACKING SOUTHWARD THROUGH THE
FORECAST PERIOD. THE AVAILABLE MODEL GUIDANCE IS IN VERY GOOD AGREE-
MENT WITH THE OFFICIAL FORECAST. TC 20P IS EXPECTED TO INTENSIFY
SLIGHTLY OVER THE NEXT 12 HOURS BUT SHOULD WEAKEN QUICKLY AS THE
AFOREMENTIONED UPPER-LEVEL TROUGH SHIFTS EAST AND DISRUPTS OUTFLOW.
ADDITIONALLY, COOLER SST WILL WEAKEN THE SYSTEM BELOW 35 KNOTS
AFTER TAU 36 LEADING TO DISSIPATION OVER WATER. THIS WARNING
SUPERSEDES AND CANCELS REF A, NAVMARFCSTCEN 110152Z MAR 09 TROPICAL
CYCLONE FORMATION ALERT (WTPS22 PGTW 110200). MAXIMUM SIGNIFICANT
WAVE HEIGHT AT 110600Z IS 8 FEET. NEXT WARNINGS AT 112100Z AND
120900Z. REFER TO TROPICAL CYCLONE 18P (HAMISH) WARNINGS (WTPS31
PGTW) FOR TWELVE-HOURLY UPDATES.

[HURAKAN]

[HURAKAN]

Gale Warning 004 ISSUED FROM RSMC NADI Mar 11/1228 UTC 2009 UTC.

Tropical Cyclone JONI 11F centre [995hPa] CATEGORY 1 was located near
21 decimal 6 South 158 decimal 6 West at 111200 UTC.
Position Poor.
Repeat position 21.6S 158.6W at 111200 UTC.
Cyclone moving southwest at about 05 knots and expected to curve
south in the next 12 to 18 hours.
Expect sustained winds of 35 knots close to the centre, increasing to
40 knots in the next 6 to 12 hours.
Expect winds over 33 knots within 150 nautical miles of centre in the
eastern semicircle.

Forecast position near 22.7S 158.8W at 120000 UTC.
and near 24.9S 158.4W at 121200 UTC.

All vessels within 300 nautical miles of centre are requested to
send
reports every three hours. VOS reporting ships use normal channels.
Other vessels fax plus 679 6720190 or email naditcc at met dot gov
dot fj.

This warning cancels and replaces warning 003.

[Chacor]

FLASH
Special Weather Bulletin Number FIVE for Southern Cooks ON TROPICAL
CYCLONE JONI
ISSUED FROM RSMC NADI Mar 11/1242 UTC 2009 UTC.


Tropical Cyclone Warning

A GALE WARNING REMAINS IN FORCE FOR RAROTONGA, MANUAE, MAUKE, MANGAIA
AND NEARBY SMALLER ISLANDS.

A STRONG WIND WARNING REMAINS IN FORCE FOR AITUTAKI.

TROPICAL CYCLONE JONI 11F [995HPA] CENTRE WAS ANALYSED NEAR 21
DECIMAL 6 SOUTH 158 DECIMAL 6 WEST AT 111200UTC OR ABOUT 41 NAUTICAL
MILES WESTNORTHWEST OF MANGAIA AND 72 NAUTICAL MILES EASTSOUTHEAST OF
RAROTONGA. JONI IS CURRENTLY MOVING SOUTHWEST AT 05 KNOTS AND IS
EXPECTED TO CURVE SOUTHWARDS IN THE NEXT 12 TO 18 HOURS. MAXIMUM 10
MINUTE AVERAGE WINDS CLOSE TO THE CENTRE ESTIMATED AT 35 KNOTS. ON
ITS CURRENT TRACK, JONI WILL BRING DAMAGING GALE FORCE WINDS OVER
RAROTONGA, MANUAE, MAUKE, MANGAIA AND NEARBY SMALLER ISLANDS FOR THE
NEXT 12 TO 24 HOURS.

FOR RAROTONGA: SOUTH TO SOUTHWEST WINDS 20 TO 25 KNOTS GUSTING 40
KNOTS, POSSIBLY INCREASING TO 25 TO 35 KNOTS IN THE NEXT 12 HOURS.
WINDS EASING AND TENDING WEST TO NORTHWEST LATER TODAY. PERIODS OF
RAIN, HEAVY AT TIMES WITH SQUALLY THUNDERSTORMS. FLOODING OF LOW
LYING COASTAL AREAS. VERY ROUGH SEAS. MODERATE NORTHERLY SWELL
DEVELOPING.

FOR MANUAE, MAUKE, MANGAIA AND NEARBY SMALLER ISLANDS: DAMAGING GALE
FORCE WINDS 30 TO 35 KNOTS WITH GUSTS UP TO 45 KNOTS. WINDS GRADUALLY
EASING FROM LATER TODAY. PERIODS OF RAIN, HEAVY AT TIMES WITH SQUALLY
THUNDERSTORMS. FLOODING OF LOW LYING COASTAL AREAS. VERY ROUGH SEAS.
MODERATE NORTHERLY SWELL DEVELOPING.

FOR AITUTAKI: WEST TO NORTHWEST WINDS 20 TO 30 KNOTS GUSTING 40
KNOTS. WINDS EASING LATER TODAY. PERIODS OF RAIN, HEAVY AT TIMES WITH
SQUALLY THUNDERSTORMS. FLOODING OF LOW LYING COASTAL AREAS. VERY
ROUGH SEAS. MODERATE NORTHERLY SWELL DEVELOPING.

FOR PALMERSTON: MODERATE SOUTHWESTERLY WINDS, TURNING WEST TO
NORTHWEST TODAY. BRIEF SHOWERS. MODERATE SEAS.

PLEASE ACKNOWLEDGE RECEIPT OF THIS BULLETIN.

THE NEXT SPECIAL WEATHER BULLETIN FOR THE SOUTHERN COOK ISLANDS WILL
BE ISSUED AROUND 111600Z OR EARLIER.

[Chacor]

TROPICAL DISTURBANCE ADVISORY NUMBER A4 ISSUED FROM RSMC NADI
Mar 11/1417 UTC 2009 UTC.

TROPICAL CYCLONE JONI 11F [995HPA] CENTRE WAS LOCATED NEAR 21.6S
158.6W AT 111200 UTC MOVING SOUTHWEST 05 KNOTS. POSITION POOR BASED
ON MTSAT/IR IMAGERY WITH ANIMATION, LATEST PERIPHERAL SURFACE
OBSERVATIONS, RECENT QUIKSCAT AND MICROWAVE PASSES. EXPECT SUSTAINED
WINDS OF 35 KNOTS CLOSE TO THE CENTRE, INCREASING TO 40 KNOTS IN THE
NEXT 6 TO 12 HOURS. EXPECT WINDS OVER 33 KNOTS WITHIN 150 NAUTICAL
MILES OF CENTRE IN THE EASTERN SEMICIRCLE.

CIMSS INDICATES THE SYSTEM WILL REMAIN IN A WEAKLY SHEARED
ENVIRONMENT AND WITH WARM SSTs [AROUND 28C] ALONG THE FORECAST TRACK
FOR THE NEXT 24 HOURS, DEVELOPMENT IS EXPECTED TO CONTINUE. DVORAK
ANALYSIS BASED ON A 0.8 WRAP ON LOG10 SPIRAL, RESULTING IN DT=3.5
MET=PT=3.0. FT BASED ON MET, YIELDING T3.0/3.0/D1.5/24HRS. AN
INTENSIFYING RIDGE OF HIGH PRESSURE TO THE SOUTHEAST OF JONI IS
ENHANCING THE PRESSURE GRADIENT TO THE EAST OF THE LLCC. AN UPPER
TROUGH IS APPROACHING THE SYSTEM FROM THE SOUTHWEST. JONI IS BEING
STEERED SOUTHWEST BY A MID LEVEL RIDGE TO THE EAST AND IS EXPECTED TO
CURVE SOUTHWARDS IN THE NEXT 12 TO 18 HOURS. GLOBAL MODELS AGREE ON A
SOUTHERLY TRACK WITH GRADUAL WEAKENING. BEYOND 24 HOURS, COOLER SSTs
AND INCREASING SHEAR WILL WEAKEN JONI.

FORECASTS:
12HRS VALID AT 120000 UTC NEAR 22.7S 158.8W MOV S 06KT WITH 40KT
CLOSE TO THE CENTRE.
24HRS VALID AT 121200 UTC NEAR 24.9S 158.4W MOV S 11KT WITH 35KT
CLOSE TO THE CENTRE.

OUTLOOK:
36HRS VALID AT 130000 UTC NEAR 27.2S 158.0W MOV S 11KT WITH 35KT
CLOSE TO THE CENTRE.
48HRS VALID AT 131200 UTC NEAR 30.8S 157.6W MOV S 18KT WITH 35KT
CLOSE TO THE CENTRE.

THE NEXT TROPICAL DISTURBANCE ADVISORY ON JONI WILL BE ISSUED AROUND
112030UTC OR EARLIER.

[HURAKAN]

[KWT]

Its got a decent circulation looking at thatIR imagery but convection seems to be in the plusing stage.

[Pedro Fernández]

Looking at the multisensor image, JONI seems to be developing an eye-feature, above all looking at the microwave image...

[HURAKAN]

Joni may be stronger than estimated.

[HURAKAN]

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

----- Current Analysis -----
Date : 11 MAR 2009 Time : 162200 UTC
Lat : 22:43:25 S Lon : 158:30:58 W


CI# /Pressure/ Vmax
3.4 / 995.3mb/ 53.0kt


Final T# Adj T# Raw T#
(3hr avg)
3.4 3.4 4.0

Latitude bias adjustment to MSLP : +0.1mb

Center Temp : -53.4C Cloud Region Temp : -57.3C

Scene Type : CURVED BAND with 0.96 ARC in LT GRAY

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : EAST PACIFIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : 0.7T/6hr
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

[HURAKAN]

The Microwave from a few hours ago may be impressive but this system convection-wise, is unimpressive.