SPAC: DONNA - Post-Tropical

[Digital-TC-Chaser]

18P DONNA 170503 0600 12.7S 171.2E SHEM 55 991


TSR map




Cranking up and looking much tighter now.

[Digital-TC-Chaser]

TPS31 PGTW 030900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (DONNA) WARNING NR 002//
RMKS/ ---
REMARKS:
030900Z POSITION NEAR 12.7S 171.0E.
TROPICAL CYCLONE 18P (DONNA), LOCATED APPROXIMATELY 344 NM
NORTH-NORTHEAST OF PORT VILA, VANUATU, HAS TRACKED WESTWARD AT 05
KNOTS OVER THE PAST SIX HOURS. THE CURRENT POSITION IS BASED ON A
LOW-LEVEL CENTER FEATURE EVIDENT IN A 030412Z SSMIS IMAGE AND RECENT
SATELLITE POSITION FIXES FROM KNES AND PGTW. THE INTENSITY OF 55
KNOTS IS CONSISTENT WITH DVORAK SATELLITE INTENSITY ESTIMATES OF
T=3.5 FROM THE SAME REPORTING AGENCIES. TC 18P HAS TURNED WESTWARD
OVER THE PAST SIX HOURS UNDER THE INFLUENCE OF A DEVELOPING
SUBTROPICAL STEERING RIDGE TO THE SOUTH. THE SYSTEM HAS STEADILY
INTENSIFIED, AND BECOME INCREASINGLY ORGANIZED, UNDER THE FAVORABLE
INFLUENCES OF STRONG POLEWARD OUTFLOW ALOFT, LOW VERTICAL WIND SHEAR
(5-10 KNOTS) AND PASSAGE OVER VERY WARM WATER (29-30C). TC 18P IS
EXPECTED TO TRACK WESTWARD TO SOUTHWESTWARD OVER THE NEXT 48 HOURS
UNDER THE CONTINUED INFLUENCE OF THE SUBTROPICAL STEERING RIDGE.
STEADY INTENSIFICATION IS ANTICIPATED AS ENVIRONMENTAL CONDITIONS
REMAIN FAVORABLE, WITH SOME GUIDANCE SUGGESTING THAT A MORE RAPID
INTENSIFICATION RATE THAN INDICATED IN THE CURRENT FORECAST IS
POSSIBLE. BY TAU 48, A BREAK IS EXPECTED TO DEVELOP IN THE STEERING
RIDGE IN RESPONSE TO AN APPROACHING MID-LATITUDE TROUGH, ALLOWING TC
18P TO TURN SHARPLY POLEWARD AROUND THE STEERING RIDGE PERIPHERY.
ADDITIONAL INTENSIFICATION IS EXPECTED INTO THE EXTENDED PERIOD, AS
POLEWARD OUTFLOW IS ENHANCED AHEAD OF THE DEVELOPING MID-LATITUDE
TROUGH. BY TAU 120, INCREASING VERTICAL WIND SHEAR ASSOCIATED WITH
UPPER-LEVEL FLOW AHEAD OF THE TROUGH SHOULD INITIATE A WEAKENING
TREND. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT REGARDING THE
OVERALL FORECAST SCENARIO OF A WESTWARD TO SOUTHWESTWARD TRACK IN
THE NEAR-TERM, FOLLOWED BY A POLEWARD TRACK IN THE MEDIUM TO
EXTENDED RANGE. HOWEVER, THERE IS CONSIDERABLE DISAGREEMENT
REGARDING THE EXACT PATH THE SYSTEM WILL FOLLOW. THE CURRENT JTWC
OFFICIAL FORECAST IS SHIFTED SLIGHTLY WESTWARD FROM THE PREVIOUS
FORECAST AND LIES WITHIN THE MODEL FORECAST ENVELOPE NOT FAR FROM
THE MULTI-MODEL CONSENSUS, WHICH HAS CONSISTENTLY INDICATED A TRACK
RUNNING PARALLEL AND NEAR TO THE VANUATU ISLAND CHAIN. CONSIDERING
THE LARGE MODEL SPREAD, THERE IS LOW CONFIDENCE IN THE JTWC TRACK
FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 030600Z IS 18 FEET. NEXT
WARNINGS AT 032100Z AND 040900Z.//

[doomhaMwx]

Latest ASCAT data(Metop A and B), between 06z and 12z today(05/03), shows max winds of 40-45kts around the center of Tropical Storm Donna(18P), which is slightly lower than JTWC's estimate of 55kts @ 06z...


^Metop A

^Metop B

[Digital-TC-Chaser]

Eye feature

[doomhaMwx]

Looking impressive on satellite imagery this Thursday morning... JTWC has upgraded it into a Category 1 Hurricane/Typhoon-strength system (Saffir-Simpson scale) a few hours ago...
The cyclone's center may have passed very close or over Tikopia island, which is a part of the Solomon islands...

(VIS imagery from Real-Earth SSEC)

[Yellow Evan]

SH, 18, 2017050400, , BEST, 0, 125S, 1686E, 75, 978, TY, 34, NEQ, 65, 75, 70, 65, 1008, 195, 15, 0, 0, P, 0, , 0, 0, DONNA, D,

JTWC has been very reasonable with this system. Likely a minimal hurricane with a somewhat well-established inner core.

[Digital-TC-Chaser]

Sure has decent outflows going.

[mrbagyo]

uh oh

[Digital-TC-Chaser]

eyewall appears roughly only 90% complete atm, The weak spot on the east side is likely due to some dry air being sucked in by the feeder band.




18P DONNA 170504 0600 12.4S 168.1E SHEM 80 977

[euro6208]

[Digital-TC-Chaser]

Tropical Cyclone Warning Number 10 for TORBA, PENAMA, SANMA and MALAMPA.

Tropical Cyclone Warning Number 10 issued by the Vanuatu Meteorology and
Geo-Hazards Department, Port Vila at 9:05pm VUT Thursday 4 May 2017 for
TORBA, PENAMA, SANMA and MALAMPA.

At 8:00pm local time today, Severe Tropical Cyclone Donna (Cat 3) was located at
12.3 degrees South 167.8 degrees East.The system is positioned at the
top right corner of square letter G, number 2 (G,2) of the Vanuatu tropical cyclone
tracking Map. This is about 170 KM northeast of Torres and
175 KM north of Vanua Lava. The system is moving in a west northwest direction
at 12 KM/HR in the past 3 hours.

The central pressure of the system is estimated at 966 hPa. Winds close to the
centre are estimated at 130 KM/HR , gusting to 190 KM/HR. Severe Tropical Cyclone
Donna is forecasted to be at 12.8 degrees South 166.9 degrees East within the next
06 to 12 hours.

Very destructive hurricane force winds of 130 KM/HR gusting to 190 KM/HR will affect
TORBA and PENAMA in the next 12 hours.

Destructive storm force winds of 95 KM/HR gusting to 135 KM/HR will affect
SANMA and MALAMPA in the next 12 to 24 hours.

Forecast Positions
Date and Time Position Intensity
+06 hours (2am, 5 May) 12.5S, 167.3E 80 KTS (150 KM/HR)
+12 hours (8am, 5 May) 12.8S, 166.9E 80 KTS (150 KM/HR)
+18 hours (2pm, 5 May) 13.1S, 166.5E 80 KTS (150 KM/HR)
+24 hours (8pm, 5 May) 13.4S, 166.2E 80 KTS (150 KM/HR)
+36 hours (8am, 6 May) 14.1S, 165.7E 80 KTS (150 KM/HR)
+48 hours (8pm, 6 May) 14.7S, 165.7E 80 KTS (150 KM/HR)

Very destructive winds and very rough to phenomenal seas with heavy swells will
affect TORBA, PENAMA, SANMA and MALAMPA. Heavy rainfall and flash flooding is
also expected over low lying areas and areas close to river banks. Coastal
flooding is also expected.

The Vanuatu National Disaster Management Office (NDMO) advises people, that
Red Alert is now current for TORBA province, Yellow Alert is now current for PENAMA
and Sanma provinces, while Blue alert is now current for MALAMPA provinces.
For actions on this alerts,call the office of the NDMO on 22699 or 33366.

The next warning on Severe Tropical Cyclone Donna will be issued at 12:00am. People
over TORBA, PENAMA, SANMA and MALAMPA and SHEFA and TAFEA should listen to all Radio
Outlets to get the latest information on this system.

This warning is also available on VMGD's website http://www.vmgd.gov.vu

http://www.vmgd.gov.vu/vmgd/index.php/f ... lone/track

[euro6208]

Up to 85 knots!

18P DONNA 170504 1200 12.5S 167.6E SHEM 85 973

[doomhaMwx]

Appears to be located just to the west of Vanuatu's Torres islands now...
The cyclone has dumped very heavy rainfall in the northern Vanuatu islands, with two weather stations recording 24hr accumulations of 135mm and 174mm (from May 4 00z to May 5 00z)...

[Digital-TC-Chaser]

Tropical Cyclone Warning Number 17 for TORBA, SANMA and MALAMPA.

Tropical Cyclone Warning Number 17 issued by the Vanuatu Meteorology and
Geo-Hazards Department, Port Vila at 6:00pm VUT Friday 5 May 2017 for
TORBA, SANMA and MALAMPA.

At 5:00pm local time today, Severe Tropical Cyclone Donna (Cat 3) was
located at 12.8 degrees South 165.9 degrees East.The system is positioned
at the bottom right corner of square letter E, number 2 (E,2) of the Vanuatu
tropical cyclone tracking Map. This is about 90 KM northwest of Torres and
230 KM northwest of Gaua. The system is moving in a southwest direction
at 6 KM/HR in the past 3 hours.

The central pressure of the system is estimated at 954 hPa. Winds close
to the centre are estimated at 145 KM/HR , gusting to 205 KM/HR.
Severe Tropical Cyclone Donna is forecasted to be at 13.3 degrees South
165.3 degrees East within the next 06 to 12 hours.

Very destructive hurricane force winds of 145 KM/HR gusting to 205 KM/HR
will affect TORBA province tonight till early tomorrow morning.

Destructive storm force winds of 95 KM/HR gusting to 135 KM/HR will affect
SANMA in the next 12 to 24 hours.

Damaging gale force winds of 75KM/hr gusting to 105 KM/HR will affect MALAMPA
in the next 24 hours.

Forecast Positions
Date and Time Position Intensity
+06 hours (11pm, 5 May) 13.1S, 165.5E 80 KTS (150 KM/HR)
+12 hours (5am, 6 May) 13.3S, 165.3E 80 KTS (150 KM/HR)
+18 hours (11am, 6 May) 13.5S, 165.0E 80 KTS (150 KM/HR)
+24 hours (5pm, 6 May) 13.8S, 164.9E 80 KTS (150 KM/HR)
+36 hours (5am, 7 May) 14.4S, 164.9E 80 KTS (150 KM/HR)
+48 hours (5pm, 7 May) 15.2S, 164.9E 80 KTS (150 KM/HR)

Very destructive winds and very rough to phenomenal seas with heavy swells will
affect TORBA, SANMA and MALAMPA. Heavy rainfall and flash flooding is also
expected over TORBA, SANMA, PENAMA and MALAMPA especially over low lying
areas and areas close to river banks. Coastal flooding is also expected.

The Vanuatu National Disaster Management Office (NDMO) advises people, that
Red Alert is now current for TORBA province, Yellow Alert is now current for
SANMA and MALAMPA province. For actions on this alerts,call the office of the
NDMO on 22699 or 33366.

The next warning on Severe Tropical Cyclone Donna will be issued at 9:00pm.
People over TORBA, SANMA and MALAMPA and PENAMA and SHEFA should listen
to all Radio Outlets to get the latest information on this system.

This warning is also available on VMGD's website http://www.vmgd.gov.vu

JTWC
50300Z POSITION NEAR 13.2S 166.0E.
TROPICAL CYCLONE 18P (DONNA), LOCATED APPROXIMATELY 302 NM NORTH-
NORTHWEST OF PORT VILA, VANUATU, HAS TRACKED WEST-SOUTHWESTWARD
AT 06 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY DEPICTS WEAKENING CONVECTION AND WARMING CLOUD
TOPS. THE INITIAL POSITION IS EXTRAPOLATED FROM A LOW REFLECTIVITY
FEATURE IN A 042215Z AMSU-B IMAGE WITH FAIR CONFIDENCE. THE INITIAL
INTENSITY IS BASED ON BOTH OBJECTIVE AND AGENCY CURRENT INTENSITY
DVORAK ESTIMATES RANGING FROM 4.5 TO 5.0 (77 TO 90 KNOTS).
ENVIRONMENTAL CONDITIONS HAVE DETERIORATED IN THE UPPER-LEVELS OVER
THE LAST SIX HOURS DUE TO A POINT SOURCE ANALYZED TO THE NORTHEAST
WHICH IS RESTRICTING OUTFLOW ON THE NORTH AND EASTERN QUADRANTS AND
CREATING A MODERATE SHEAR ENVIRONMENT. STRONG POLEWARD DIFFLUENCE
IS STILL EVIDENT IN SATELLITE IMAGERY TAPPING INTO THE MID-LATITUDE
JET. SSTS ARE ALSO VERY WARM IN THE REGION, NEAR 30 CELSIUS.
CURRENTLY TC DONNA IS TRACKING WEST-SOUTHWESTWARD GUIDED BY A
SUBTROPICAL RIDGE TO THE SOUTH. A BREAK IN THE STEERING RIDGE IS
EXPECTED IN THE NEXT 12 TO 24 HOURS SLOWING THE SYSTEM DOWN AS A
RIDGE TO THE SOUTHWEST COMPETES WITH THE DOMINANT SOUTHEAST RIDGE.
OVER THE NEXT 24 HOURS MODERATE SHEAR DUE TO NORTHEASTERLY FLOW
ALOFT IS EXPECTED TO PERSIST AND WILL MITIGATE DEVELOPMENT. BEYOND
TAU 24 A LONGWAVE TROUGH WILL MOVE INTO THE REGION ENHANCING
OUTFLOW, AND PRIME TC DONNA FOR ANOTHER PERIOD OF INTENSIFICATION.
PEAK INTENSITY IS EXPECTED TO REACH 110 BY TAU 48. THE APPROACHING
TROUGH WILL ALSO ERODE THE WESTERN RIDGE AND THE SYSTEM WILL TURN
AND BEGIN TO ACCELERATE TO THE SOUTHEAST AROUND TAU 48. HIGH WINDS
ALOFT ASSOCIATED WITH THE TROUGH WILL INTRODUCE SIGNIFICANT VERTICAL
WIND SHEAR AND BEGIN WEAKENING THE SYSTEM AFTER TAU 72. NUMERICAL
MODEL GUIDANCE IS COMING INTO BETTER AGREEMENT WITH THE TRACK
TRAJECTORY, HOWEVER THERE IS STILL A LARGE DEGREE OF UNCERTAINTY IN
THE EXACT POSITION AND TIMING TC DONNA WILL MAKE THE TURN TO THE
SOUTHEAST. OVERALL, THE AVAILABLE GUIDANCE HAS SHIFTED THE TRACK TO
THE WEST IN RECENT MODEL RUNS, AND THIS TREND IS BEGINNING TO
STABILIZE, THUS IMPROVING CONFIDENCE IN THE FORECAST TRACK. DUE TO
THE INHERENT UNCERTAINTY IN THE SOUTHWARD TURN, THERE IS OVERALL LOW
CONFIDENCE IN THE FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT
041800Z IS 28 FEET. NEXT WARNINGS AT 050300Z, 050900Z, 051500Z AND
052100Z.//
NNNN]

18P DONNA 170505 0600 13.6S 165.6E SHEM 90 969




EC00z still modeling 936mb core.

[doomhaMwx]

Latest model runs have the system reaching peak intensity and move southeastward farther west from Vanuatu, keeping the area of Hurricane/Typhoon-force winds well far from them... The cyclone could still bring Tropical Storm-force winds in most of the island chain though, while moving SE on the next few days...
This westward shift in the models also means that the New Caledonia islands could see some effects from the cyclone early/mid next week...

[Digital-TC-Chaser]

http://satview.bom.gov.au/

[Digital-TC-Chaser]

TROPICAL DISTURBANCE ADVISORY NUMBER A13 ISSUED FROM RSMC NADI
May 060212 UTC.

SEVERE TROPICAL CYCLONE DONNA CENTRE 963HPA WAS LOCATED NEAR 13.3S
163.7E AT 060000 UTC. POSITION POOR BASED ON HR HIMAWARI-8 EIR
IMAGERY AND PERIPHERAL SURFACE REPORTS. CYCLONE WEST SOUTHWEST AT
ABOUT 07 KTS. MAXIMUM 10-MINUTE AVERAGE WINDS NEAR THE CENTRE
ESTIMATED AT ABOUT 90 KNOTS.

DEEP CONVECTION REDUCED IN RADIAL EXTENT DUE TO DRY AIR ENTRAINMENT
FROM EAST. ORGANIZATION REMAINS GOOD. SYSTEM LIES JUST NORTH OF AN
UPPER RIDGE IN MODERATE SHEARED ENVIRONMENT WITH GOOD POLEWARD
OUTFLOW. SST AROUND 29 DEGREES CELCIUS. SYSTEM STEERED WEST SOUTHWEST
ALONG THE PERIPHERY OF A MID LEVEL SUBTROPICAL HIGH. DVORAK ANALYSIS
BASED ON EMBEDDED CENTER WITH LG SURROUND, YIELDS DT=4.5, MET AND PT
5.0. FT BASED ON MET. THUS YIELDING, T5.0/5.5/D0.5/24HRS.

FORECASTS :
AT 12 HRS VALID AT 061200 UTC 13.6S 163.5E MOV SSW AT 02 KT WITH 85
KT CLOSE TO CENTRE
AT 24 HRS VALID AT 070000 UTC 14.2S 163.5E MOV W AT 02 KT WITH 80 KT
CLOSE TO CENTRE

OUTLOOK :
AT 36 HRS VALID AT 071200 UTC 15.3S 163.6E MOV S AT 03 KT WITH 80 KT
CLOSE TO CENTRE
AT 48 HRS VALID AT 080000 UTC 16.4S 163.8E MOV S AT 04 KT WITH 75 KT
CLOSE TO CENTRE

Name: Severe Tropical Cyclone DONNA
Situation At: 0000 UTC Saturday 6 May 2017
Location: 13.3S, 163.7E
Recent Movement: W at 26 km/h

Fiji time is UTC +12 hours.
For example, 0000 UTC Saturday is 1200 Saturday Fiji time.
For example, 1800 UTC Saturday is 0600 Sunday Fiji time.

Category Cyclone 1 has mean winds 34-47 knots with a central pressure greater than 985 hPa
Category Cyclone 2 has mean winds 48-63 knots with a central pressure 985-970 hPa
Category Cyclone 3 has mean winds 64-85 knots with a central pressure 970-945 hPa
Category Cyclone 4 has mean winds 86-107 knots with a central pressure 945-910 hPa
Category Cyclone 5 has mean winds greater than 107 knots with a central pressure less than 910 hPa

Australian Fiji intensity scale





JTWC best track ..18P DONNA 170506 0000 13.1S 163.9E SHEM 85 971

WTPS31 PGTW 060300
REMARKS:
060300Z POSITION NEAR 13.1S 163.8E. TROPICAL CYCLONE 18P (DONNA),
LOCATED APPROXIMATELY 375 NM NORTHWEST OF PORT VILA, VANUATU, HAS
TRACKED NORTHWESTWARD AT 06 KNOTS OVER THE PAST SIX HOURS. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY (MSI) REVEALS A SIGNIFICANTLY
WEAKENED CONVECTIVE SIGNATURE, WITH THE PREVIOUSLY ESTABLISHED
CENTRAL COLD COVER (CCC) HAVING COMPLETELY DISSIPATED, WITH ONLY
PATCHY MODERATE CONVECTION. AS OF THE LATE 0000Z HOUR, SIGNS OF
REDEVELOPMENT OF DEEP CONVECTION HAVE APPEARED, BUT IT IS TOO EARLY
TO DETERMINE IF THIS WILL STICK. THE INITIAL POSITION IS PLACED WITH
MODERATE CONFIDENCE BASED ON ANALYSIS OF THE AVAILABLE HIGH
RESOLUTION VISIBLE IMAGERY AND A 2156Z AMSU 89 GHZ MICROWAVE IMAGE
AND COINCIDENT ASCAT-B PASS, WITH A WELL DEFINED LOW LEVEL
CIRCULATION CENTER (LLCC), STILL SHIELDED FROM VIEW BY UPPER-LEVEL
CLOUD COVER. THE INITIAL INTENSITY OF 85 KNOTS IS BASED ON
ASSESSMENT OF REPORTING AGENCY AND AUTOMATED DVORAK CURRENT
INTENSITY ESTIMATES BETWEEN 4.5 AND 5.0 AND SUPPORTED BY THE OVERALL
WEAKENED APPEARANCE OF THE SYSTEM. BASED ON ANALYSIS OF THE UPPER-
LEVEL DATA, THE RECENT WEAKENING PHASE WILL BE SHORT LIVED, AND WAS
DRIVEN BY AN INCREASED NORTHEASTERLY UPPER-LEVEL FLOW OVER TOP OF
THE SYSTEM. RECENT ANALYSIS INDICATES A SHIFT FROM THIS
NORTHEASTERLY FLOW PATTERN TO DEVELOPMENT OF AN UPPER-LEVEL POINT
SOURCE IN THE NEAR TERM. THE OVERALL ENVIRONMENT REMAINS SUPPORTIVE
OF INTENSIFICATION WITH WARM SSTS NEAR 29 CELSIUS, A STRONG POLEWARD
OUTFLOW CHANNEL AND LOW TO MODERATE VERTICAL WIND SHEAR (VWS) VALUES
BETWEEN 15-20 KNOTS. OVER THE PAST SIX HOURS, TC DONNA HAS CONTINUED
TO TRACK WEST-NORTHWESTWARD UNDER THE INFLUENCE OF AN ELONGATED
SUBTROPICAL RIDGE (STR) AXIS ALONG TONGA TO NEW CALEDONIA TO
NORTHEAST AUSTRALIA AXIS, WHICH CONTINUES TO INHIBIT SOUTHWARD
MOVEMENT AT THIS TIME. THIS RIDGE IS EXPECTED TO BREAK DOWN AND
REORIENT TO A MORE NORTH-SOUTH AXIS BY TAU 24, ALLOWING TC DONNA TO
TURN POLEWARD AND ACCELERATE THROUGH THE REMAINDER OF THE FORECAST.
AS THE AFOREMENTIONED POINT SOURCE DEVELOPS OVER TOP OF THE SYSTEM,
ENVIRONMENTAL CONDITIONS WILL BE RIPE FOR FURTHER INTENSIFICATION
THROUGH TAU 48, PEAKING AT 110 KNOTS BEFORE BEGINNING A WEAKENING
TREND AFTER TAU 72 AS VWS INCREASES AND SSTS DECREASE. TC DONNA WILL
BEGIN TO UNDERGO EXTRATROPICAL TRANSITION BY TAU 96 THROUGH THE
REMAINDER OF THE FORECAST. NUMERICAL MODEL GUIDANCE IS IN GOOD
AGREEMENT WITH EGRR REMAINING AS THE SOLE EASTWARD OUTLIER, LEADING
TO TO HIGH CONFIDENCE IN THE JTWC TRACK FORECAST. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 050600Z IS 30 FEET. MAXIMUM SIGNIFICANT
WAVE HEIGHT AT 060000Z IS 30 FEET. NEXT WARNINGS AT 060900Z,
061500Z, 062100Z AND 070300Z.//

SSHS scale C2
TSR

[euro6208]

[euro6208]

WTPS31 PGTW 070900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (DONNA) WARNING NR 015//
RMKS/
1. TROPICAL CYCLONE 18P (DONNA) WARNING NR 015
01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
070600Z --- NEAR 14.6S 164.6E
MOVEMENT PAST SIX HOURS - 150 DEGREES AT 08 KTS
POSITION ACCURATE TO WITHIN 015 NM
POSITION BASED ON EYE FIXED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 160 NM NORTHEAST QUADRANT
155 NM SOUTHEAST QUADRANT
160 NM SOUTHWEST QUADRANT
125 NM NORTHWEST QUADRANT
REPEAT POSIT: 14.6S 164.6E
---
FORECASTS:
12 HRS, VALID AT:
071800Z --- 16.3S 164.9E
MAX SUSTAINED WINDS - 095 KT, GUSTS 115 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 095 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 190 NM NORTHEAST QUADRANT
200 NM SOUTHEAST QUADRANT
175 NM SOUTHWEST QUADRANT
125 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 165 DEG/ 08 KTS
---
24 HRS, VALID AT:
080600Z --- 17.8S 165.3E
MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 055 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 095 NM NORTHEAST QUADRANT
110 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 190 NM NORTHEAST QUADRANT
215 NM SOUTHEAST QUADRANT
170 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 160 DEG/ 09 KTS
---
36 HRS, VALID AT:
081800Z --- 19.4S 166.0E
MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 045 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 085 NM NORTHEAST QUADRANT
095 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 165 NM NORTHEAST QUADRANT
210 NM SOUTHEAST QUADRANT
150 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 145 DEG/ 10 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
090600Z --- 21.1S 167.2E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 064 KT WINDS - 035 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 065 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 160 NM NORTHEAST QUADRANT
180 NM SOUTHEAST QUADRANT
130 NM SOUTHWEST QUADRANT
095 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 140 DEG/ 12 KTS
---
72 HRS, VALID AT:
100600Z --- 24.7S 170.4E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
EXTRATROPICAL
RADIUS OF 034 KT WINDS - 135 NM NORTHEAST QUADRANT
180 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
---
REMARKS:
070900Z POSITION NEAR 15.0S 164.7E.
TROPICAL CYCLONE (TC) 18P (DONNA), LOCATED APPROXIMATELY 283 NM
NORTHWEST OF PORT VILA, VANUATU, HAS TRACKED SOUTH-SOUTHEASTWARD
AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY DEPICTS IMPROVED CONVECTIVE ORGANIZATION WITH A 17-
NM EYE EVIDENT, HOWEVER, DEEP CONVECTION CONTINUES TO CYCLE RAPIDLY.
A 070500Z SSMIS 91 GHZ IMAGE SHOWS ASYMMETRIC CORE CONVECTION WITH A
DEEP CONVECTIVE BAND OVER THE WESTERN SEMI-CIRCLE AND SHALLOW
BANDING OVER THE EASTERN SEMI-CIRCLE OF THE EYEWALL. UPPER-LEVEL
ANALYSIS INDICATES CYCLONIC FLOW OVER THE CORE, WHICH IS LIKELY
CONTRIBUTING TO THE FLAT TREND AND PULSATING CONVECTION, DIVERGING
INTO A STRONG POLEWARD OUTFLOW CHANNEL TO THE SOUTHWEST. THE CURRENT
INTENSITY REMAINS ASSESSED AT 85 KNOTS BASED ON AN AVERAGE OF
4.5/5.0 DVORAK ESTIMATES FROM PGTW, KNES AND PHFO. CURRENT MODEL
ANALYSES INDICATE THAT THE WESTERN SUBTROPICAL RIDGE (STR) HAS
ERODED DUE TO AN APPROACHING MAJOR SHORTWAVE TROUGH, THEREFORE, THE
EASTERN STR IS NOW THE DOMINANT STEERING RIDGE. CONSEQUENTLY, TC 18P
HAS ACCELERATED SOUTHWARD AS IT TRACKS ALONG THE WESTERN PERIPHERY
OF THE STR. TC DONNA SHOULD CONTINUE TO TRACK SOUTHWARD TO SOUTH-
SOUTHEASTWARD THROUGH THE FORECAST PERIOD. DYNAMIC GUIDANCE REMAINS
IN TIGHT AGREEMENT LENDING HIGH CONFIDENCE TO THE JTWC FORECAST
TRACK. TC 18P IS FORECAST TO INTENSIFY SLIGHTLY WITHIN THE NEXT 24
HOURS DUE TO WARM SST AND ROBUST POLEWARD OUTFLOW WITH SOME
UNCERTAINTY DUE TO THE COMPLEX UPPER-LEVEL FLOW OVER THE CORE. AFTER
TAU 24, GRADUAL WEAKENING SHOULD OCCUR AS THE SYSTEM TRACKS OVER
MARGINAL SST. BY TAU 48, TC 18P WILL BEGIN EXTRA-TROPICAL TRANSITION
AND RAPIDLY WEAKEN AS IT INTERACTS WITH THE MIDLATITUDE WESTERLIES
AND THE WEAK BAROCLINIC ZONE. THE SYSTEM IS EXPECTED TO COMPLETE
EXTRA-TROPICAL TRANSITION AS IT BECOMES EMBEDDED WITHIN THE
MIDLATITUDE WESTERLIES. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 070600Z
IS 24 FEET. NEXT WARNINGS AT 071500Z, 072100Z, 080300Z AND 080900Z.//
NNNN

[euro6208]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.2.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 07 MAY 2017 Time : 091000 UTC
Lat : 15:04:24 S Lon : 164:39:10 E


CI# /Pressure/ Vmax
5.4 / 958.3mb/ 99.6kt


Final T# Adj T# Raw T#
5.4 5.6 5.6

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

Center Temp : +4.4C Cloud Region Temp : -63.1C

Scene Type : EYE

Positioning Method : RING/SPIRAL COMBINATION

Ocean Basin : WEST PACIFIC
Dvorak CI > MSLP Conversion Used : CKZ Method

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

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 150km
- Environmental MSLP : 1010mb

Satellite Name : HIM-8
Satellite Viewing Angle : 32.4 degrees

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