SPAC: DONNA - Post-Tropical

[Digital-TC-Chaser]

18P DONNA 170507 1200 15.5S 164.8E SHEM 85 959

[doomhaMwx]

JTWC Warning #16
Up to 95kts...

REMARKS:
071500Z POSITION NEAR 15.9S 164.8E.
TROPICAL CYCLONE (TC) 18P (DONNA), LOCATED APPROXIMATELY 241 NM WEST- NORTHWEST OF PORT VILA, VANUATU, HAS TRACKED SOUTHWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS STRENGTHENING, ASYMMETRIC EYEWALL CONVECTION SURROUNDING A 21-NM EYE. A 071052Z METOP-A 89 GHZ IMAGE SHOWS DEEP CONVECTION PRIMARILY OVER THE WESTERN SEMI-CIRCLE AND SHALLOW CONVECTION OVER THE EASTERN SEMI-CIRCLE. UPPER-LEVEL ANALYSIS INDICATES CYCLONIC FLOW OVER THE SYSTEM, WHICH IS LIKELY CONTRIBUTING TO THE PULSATING, ASYMMETRIC CORE CONVECTION, DIVERGING INTO A STRONG POLEWARD OUTFLOW CHANNEL TO THE SOUTHWEST. THE CURRENT INTENSITY IS ASSESSED AT 95 KNOTS BASED ON AN AVERAGE OF DVORAK ESTIMATES RANGING FROM T5.0 TO T5.5. 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 DOMINANT STR. TC DONNA SHOULD CONTINUE TO TRACK SOUTHWARD TO SOUTH-SOUTHEASTWARD THROUGH THE FORECAST PERIOD. DYNAMIC GUIDANCE REMAINS IN GOOD AGREEMENT LENDING HIGH CONFIDENCE TO THE JTWC FORECAST TRACK. TC 18P IS FORECAST TO INTENSIFY SLIGHTLY WITHIN THE NEXT 12 HOURS DUE TO WARM SST AND ROBUST POLEWARD OUTFLOW WITH SOME UNCERTAINTY DUE TO THE COMPLEX UPPER-LEVEL FLOW OVER THE CORE. AFTER TAU 12, GRADUAL WEAKENING SHOULD OCCUR AS THE SYSTEM TRACKS OVER MARGINAL SST. BY TAU 36, 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 071200Z IS 27 FEET. NEXT WARNINGS AT 072100Z, 080300Z, 080900Z AND 081500Z. //
NNNN

[Yellow Evan]

SH, 18, 201705071730, 10, DVTS, CI, , 1650S, 16490E, , 1, 115, 2, , , , , , , , , , , , , , , , , P, KNES, FS, IM, 1, 6060 /////, , , HMWRI8, LLCC, T, DT=6.0 BO EYE MET=6.0 PT=6.0 FTBO DT

Not bad.

[1900hurricane]

18P DONNA 170507 1800 16.5S 164.8E SHEM 120 939

I probably wouldn't have gone quite that high, but this (and anything over 95 kt) makes Donna the strongest SPac system observed in May.

Here's the 18Z BD snapshot.

[Digital-TC-Chaser]

Tropical Cyclone Warning Number 38 for SANMA, MALAMPA, PENAMA and SHEFA.

Tropical Cyclone Warning Number 38 issued by the Vanuatu Meteorology and
Geo-Hazards Department, Port Vila at 8:57am VUT Monday 8 May 2017 for
SANMA, MALAMPA, PENAMA and SHEFA.

At 8:00am local time today, Severe Tropical Cyclone Donna (Cat 4) was located
at 16.7 degrees South 164.6 degrees East.The system is positioned at the
center of square letter D, number 6 (D, 6) of the Vanuatu tropical cyclone
tracking Map. This is about 310 KM west of Malekula and 415 KM west northwest
of Efate. The system is moving in the south southwesterly direction at 17 KM/HR
in the past 3 hours.

The central pressure of the system is estimated at 927 hPa. Winds close to
the centre are estimated at 185 KM/HR , gusting to 265 KM/HR.
Severe Tropical Cyclone Donna is forecasted to be at 18.2 degrees South
165.0 degrees East within the next 06 to 12 hours.

Destructive storm force winds of 110 KM/HR gusting to 160 KM/HR will affect
SANMA and MALAMPA today, extending to SHEFA tonight.

Damaging gale force winds of 75KM/HR gusting to 105 KM/HR will continue to
affect TORBA and PENAMA province. Winds over TORBA will weaken as the system
moves further south.

Forecast Positions
Date and Time Position Intensity
+06 hours (2pm, 8 May) 17.5S, 164.8E 100 KTS (185 KM/HR)
+12 hours (8pm, 8 May) 18.2S, 165.0E 100 KTS (185 KM/HR)
+18 hours (2am, 9 May) 18.9S, 165.3E 100 KTS (185 KM/HR)
+24 hours (8am, 9 May) 19.6S, 165.7E 100 KTS (185 KM/HR)
+36 hours (8pm, 9 May) 21.0S, 166.3E 100 KTS (185 KM/HR)
+48 hours (8am, 10 May) 22.6S, 167.1E 90 KTS (165 KM/HR)

Destructive winds will affect, SANMA, MALAMPA, and SHEFA province. Very
rough to phenomenal seas with heavy swells will affect these province. Heavy
rainfall and flash flooding is also expected especially over low lying areas
and areas close to river banks. Possible land slide and coastal flooding is
also expected.

The Vanuatu National Disaster Management Office (NDMO) advises people, that Red
Alert is active for SANMA and MALAMPA, while Yellow alert for PENAMA and SHEFA
province and Blue Alert is current for TAFEA province. NDMO has given all clear
for TORBA 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 12:00pm.
People over SANMA, MALAMPA, PENAMA and SHEFA and SHEFA and TAFEA should listen
to all Radio Outlets to get the latest information on this system.

http://tropic.ssec.wisc.edu/real-time/a ... Table.html

[1900hurricane]

Donna is looking pretty good at the moment, that's for sure.

[Digital-TC-Chaser]

If the outflow tucks in some more DONNA will have a annular appearance.

[1900hurricane]

[Yellow Evan]

Seems to be around 120 or 125 knots. Could approach Cat 5 status (SSHWS) if the eye warms further.

[doomhaMwx]

As of 00z May 08, 2017:
Category 4 (JTWC ; Saffir-Simpson scale)
Category 5 (RSMC Nadi ; Australian scale)

=======================================
HURRICANE WARNING 038 ISSUED FROM RSMC NADI May 080118 UTC.

SEVERE TROPICAL CYCLONE DONNA CENTRE 937HPA CATEGORY 5 WAS LOCATED NEAR 17.0 SOUTH 164.8 EAST AT 080000 UTC.
POSITION GOOD.
REPEAT POSITION 17.0S 164.8E at 080000 UTC.
CYCLONE MOVING SOUTH-SOUTHEAST AT 08 KNOTS.
EXPECT SUSTAINED WINDS OF 110 KNOTS CLOSE TO THE CENTRE.
http://www.met.gov.fj/aifs_prods/20008.txt
=======================================


http://i.imgur.com/T5EtjlB.jpg

[Digital-TC-Chaser]

TROPICAL DISTURBANCE ADVISORY NUMBER A21 ISSUED FROM RSMC NADI
May 080209 UTC.

SEVERE TROPICAL CYCLONE DONNA CENTRE 937HPA WAS LOCATED NEAR 17.0S
164.8E AT 080000 UTC. POSITION GOOD BASED ON HR HIMAWARI-8 VIS/EIR
IMAGERY AND PERIPHERAL SURFACE REPORTS. CYCLONE MOVING
SOUTH-SOUTHEAST AT ABOUT 8 KTS. MAXIMUM 10-MINUTE AVERAGE WINDS NEAR
THE CENTRE ESTIMATED AT ABOUT 110 KNOTS.

DEEP CONVECTION REMAINS PERSISTANT WITH CLOUD TOP COOLING.
ORGANIZATION REMAINS GOOD WITH EYE CLEARLY DEFINED. SYSTEM LIES
UNDER AN UPPER RIDGE IN LOW SHEARED ENVIRONMENT WITH GOOD POLEWARD
OUTFLOW. SST AROUND 27 DEGREES CELCIUS. SYSTEM STEERED
SOUTH-SOUTHEAST ALONG THE PERIPHERY OF A MID LEVEL SUBTROPICAL HIGH.
DVORAK ANALYSIS BASED ON DG EYE WITH W SURROUND/RING YIELDS DT=6.5,
MET AND PT AGREE. FT BASED ON DT. THUS YIELDING, T6.5/6.5/D1.5/24HRS.

FORECASTS :
AT 12 HRS VALID AT 081200 UTC 18.6S 165.4E MOV SSE AT 08 KT WITH 110
KT CLOSE TO CENTRE
AT 24 HRS VALID AT 090000 UTC 20.0S 166.0E MOV SSE AT 08 KT WITH 110
KT CLOSE TO CENTRE

OUTLOOK :
AT 36 HRS VALID AT 091200 UTC 21.4S 166.7E MOV SSE AT 08 KT WITH 95
KT CLOSE TO CENTRE
AT 48 HRS VALID AT 100000 UTC 23.0S 167.7E MOV SSE AT 08 KT WITH 80
KT CLOSE TO CENTRE

THE NEXT TROPICAL DISTURBANCE ADVISORY ON TROPICAL CYCLONE DONNA WILL
BE ISSUED AROUND 080800 UTC.

[Yellow Evan]

Seems to be around 125, in agreement with a DT of T6.5 from JTWC.

[euro6208]

WTPS31 PGTW 080900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TROPICAL CYCLONE 18P (DONNA) WARNING NR 019
01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
080600Z --- NEAR 17.5S 165.1E
MOVEMENT PAST SIX HOURS - 155 DEGREES AT 07 KTS
POSITION ACCURATE TO WITHIN 020 NM
POSITION BASED ON EYE FIXED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 115 KT, GUSTS 140 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 055 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
180 NM SOUTHEAST QUADRANT
160 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
REPEAT POSIT: 17.5S 165.1E
---
FORECASTS:
12 HRS, VALID AT:
081800Z --- 18.8S 165.8E
MAX SUSTAINED WINDS - 110 KT, GUSTS 135 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
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
195 NM SOUTHEAST QUADRANT
160 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 155 DEG/ 08 KTS
---
24 HRS, VALID AT:
090600Z --- 20.3S 166.6E
MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
015 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 065 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 160 NM NORTHEAST QUADRANT
180 NM SOUTHEAST QUADRANT
125 NM SOUTHWEST QUADRANT
095 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 145 DEG/ 09 KTS
---
36 HRS, VALID AT:
091800Z --- 21.8S 167.7E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 160 NM NORTHEAST QUADRANT
170 NM SOUTHEAST QUADRANT
105 NM SOUTHWEST QUADRANT
080 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 140 DEG/ 12 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
100600Z --- 23.7S 169.3E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
010 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
010 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 145 NM NORTHEAST QUADRANT
160 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 140 DEG/ 15 KTS
---
72 HRS, VALID AT:
110600Z --- 28.2S 174.0E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
EXTRATROPICAL
RADIUS OF 034 KT WINDS - 165 NM NORTHEAST QUADRANT
175 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
---
REMARKS:
080900Z POSITION NEAR 17.8S 165.3E.
TROPICAL CYCLONE (TC) 18P (DONNA), LOCATED APPROXIMATELY 183 NM WEST
OF PORT VILA, VANUATU, HAS TRACKED SOUTH-SOUTHEASTWARD AT 07 KNOTS
OVER THE PAST SIX HOURS. AFTER A PERIOD OF RAPID INTENSIFICATION, TC
18P APPEARS TO BE WEAKENING SLIGHTLY WITH THE EYE BECOMING CLOUD-
FILLED AND CORE CONVECTION INCREASINGLY ASYMMETRIC. A 080446Z SSMIS
91 GHZ IMAGE INDICATES EROSION OF EYEWALL CONVECTION OVER THE WEST
QUADRANT WITH THE BULK OF DEEP CONVECTION NOW OVER THE SOUTHERN SEMI-
CIRCLE. TC 18P PEAKED EARLIER NEAR 120 KNOTS BUT IS NOW ASSESSED AT
115 KNOTS BASED ON THE LOWER END OF DVORAK ESTIMATES RANGING FROM
115 TO 127 KNOTS (T6.0 TO 6.5), CONSISTENT WITH THE CONVECTIVE
STRUCTURE. TC 18P IS FORECAST TO TRACK SOUTH-SOUTHEASTWARD THROUGH
THE FORECAST PERIOD ALONG THE WESTERN PERIPHERY OF A NORTH-SOUTH
ORIENTED SUBTROPICAL RIDGE. DYNAMIC GUIDANCE REMAINS IN GOOD
AGREEMENT LENDING HIGH CONFIDENCE TO THE FORECAST TRACK. TC DONNA IS
EXPECTED TO WEAKEN GRADUALLY AS IT TRACKS EAST OF NEW CALEDONIA DUE
TO COOLER SST AND LAND INTERACTION. AFTER TAU 24, THE SYSTEM WILL
BEGIN EXTRA-TROPICAL TRANSITION (ETT) AS IT INTERACTS WITH A MAJOR
SHORTWAVE TROUGH AND BAROCLINIC ZONE. RAPID WEAKENING IS EXPECTED
AFTER TAU 36 DUE TO STRONG VERTICAL WIND SHEAR AND COLD SST. TC 18P
SHOULD COMPLETE ETT BY TAU 60. MAXIMUM SIGNIFICANT WAVE HEIGHT AT
080600Z IS 27 FEET. NEXT WARNINGS AT 081500Z, 082100Z, 090300Z AND
090900Z.//
NNNN

[1900hurricane]

Donna is now clearly showing the effects of mid-latitude shear, but not before becoming the strongest SHem May tropical cyclone in reliable history.



 https://twitter.com/philklotzbach/status/861327131590119425




*Edit to add mistakenly omitted SHem.

[doomhaMwx]

Now over waters near New Caledonia's Loyalty islands...
Radar imagery near 3pm local time(4am UTC) today(May 09) showed that the cyclone's eye/center has passed to the north of Ouvea island...

[doomhaMwx]

Donna's a goner.

[doomhaMwx]

JTWC final warning...



SUBJ: TROPICAL CYCLONE 18P (DONNA) WARNING NR 025
WTPS31 PGTW 100900

1. TROPICAL CYCLONE 18P (DONNA) WARNING NR 025
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
100600Z --- NEAR 22.9S 168.0E
MOVEMENT PAST SIX HOURS - 175 DEGREES AT 15 KTS
POSITION ACCURATE TO WITHIN 020 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
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT
145 NM SOUTHEAST QUADRANT
120 NM SOUTHWEST QUADRANT
095 NM NORTHWEST QUADRANT
REPEAT POSIT: 22.9S 168.0E
---
FORECASTS:
12 HRS, VALID AT:
101800Z --- 25.6S 168.7E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---

REMARKS:
100900Z POSITION NEAR 23.6S 168.2E.
TROPICAL CYCLONE 18P (DONNA), LOCATED APPROXIMATELY 116 NM EAST-
SOUTHEAST OF NOUMEA, NEW CALEDONIA, HAS TRACKED SOUTHWARD AT 15
KNOTS OVER THE PAST SIX HOURS.
THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON
WRNCEN PEARL HARBOR HI. THE SYSTEM WILL BE CLOSELY MONITORED FOR
SIGNS OF REGENERATION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 100600Z
IS 12 FEET.
REFER TO TROPICAL CYCLONE 19P (ELLA) WARNINGS (WTPS32 PGTW)
FOR SIX-HOURLY UPDATES.//
NNNN

[doomhaMwx]

Cyclone Donna seen from the Int'l Space Station(ISS)... This video was captured on May 7th/8th and released on May 9th...
http://www.friendsofnasa.org/2017/05/tr ... c.html?m=1

 https://twitter.com/Space_Station/status/862054716972335104