Severe TC GITA

[Willoughby]

Phillip Duncan corrected him straight away on twitter, nice work.
https://twitter.com/Jamienzherald/statu ... 4827030528

Nadi have Gita at 930 hPa at the moment... beast.

TROPICAL DISTURBANCE ADVISORY NUMBER A16 ISSUED FROM RSMC NADI
Feb 120148 UTC.

SEVERE TROPICAL CYCLONE GITA CENTRE 930HPA WAS LOCATED NEAR 21.7S
172.6W AT 120000 UTC. POSITION GOOD BASED ON HR HIMAWARI-8
IR/EIR/VIS IMAGERY AND PERIPHERAL SURFACE REPORTS. GITA MOVING WEST
AT ABOUT 13 KNOTS. MAXIMUM 10-MINUTE AVERAGE WINDS NEAR THE CENTRE
ESTIMATED AT ABOUT 105 KNOTS.

EXPECT WINDS OVER 63 KNOTS WITHIN 50 NAUTICAL MILES OF CENTRE
EXPECT WINDS OVER 47 KNOTS WITHIN 80 NAUTICAL MILES IN NE QUADRANT
AND WITHIN 100 NAUTICAL MILES IN SE QUADRANT
AND WITHIN 120 NAUTICAL MILES IN SW QUADRANT
AND WITHIN 80 NAUTICAL MILES IN NW QUADRANT
EXPECT WINDS OVER 33 KNOTS WITHIN 180 NAUTICAL MILES IN NE QUADRANT
AND WITHIN 220 NAUTICAL MILES IN SE QUADRANT
AND WITHIN 240 NAUTICAL MILES IN SW QUADRANT
AND WITHIN 160 NAUTICAL MILES IN NW QUADRANT.

DEEP CONVECTION PERSISTANT AND ORGANISATION REMAINS GOOD. EYE
DISCERNIBLE ON IR. CYCLONIC CIRCULATION EXTENDS UP TO 300HPA WITH
OUTFLOW GOOD. SYSTEM LIES IN A LOW SHEARED ENVIRONMENT WITH GOOD
UPPER DIVERGENCE. SST AROUND 29 DEGREES. GITA CURRENTLY TRACKING WEST
ALONG THE PERIPHERY OF THE SUBTROPICAL RIDGE POSITIONED TO THE SOUTH.

DVORAK ANALYSIS BASED ON EYE PATTERN WITH DG EYE AND B SURROUND. THUS
DT=6.0, METAND PT AGREE. FT BASED ON DT THUS, YIELDING
T6.0/6.0/D1.0/24HRS


FORECASTS :
AT 12 HRS VALID AT 121200 UTC 21.5S 175.2W MOV W AT 12 KT WITH 110
KT CLOSE TO CENTRE
AT 24 HRS VALID AT 130000 UTC 21.1S 177.8W MOV W AT 12 KT WITH 115
KT CLOSE TO CENTRE

OUTLOOK :
AT 36 HRS VALID AT 131200 UTC 21.0S 180.0W MOV W AT 12 KT WITH 120
KT CLOSE TO CENTRE
AT 48 HRS VALID AT 140000 UTC 21.1S 178.2E MOV W AT 11 KT WITH 120
KT CLOSE TO CENTRE

THE NEXT TROPICAL DISTURBANCE ADVISORY ON SEVERE TROPICAL CYCLONE
GITA WILL BE ISSUED AROUND 120800UTC.

http://www.met.gov.fj/current_warnings_b.php

[ScottyD]

http://www.usno.navy.mil/NOOC/nmfc-ph/R ... sh0918.gif

Latest from JTWC

[Cyclone Tracy]

American intensification calculations now have GITA having sustained winds of 110 knots and gusts of 135 knots. Fiji met service should pull the trigger soon and call it a cat 5 I should imagine.

[Willoughby]

With any luck, the small core of very destructive winds stays to the south of the islands tonight...

[Cyclone Tracy]

She has dropped 24 hPa in 8 hours. Sustained wind increase of 32 knots in 8 hours making GITA officially a Rapid intensification Cyclone according to the United States National Hurricane Center definition. In fact she got there with 16 hours up her sleeve

[Willoughby]

Nadi maintains Cat 4 and 930mb centre at 06 UTC update:

HURRICANE WARNING 027 ISSUED FROM RSMC NADI Feb 120703 UTC.

TROPICAL CYCLONE GITA CENTRE 930HPA CATEGORY 4 WAS LOCATED NEAR 21.7 SOUTH 174.0
WEST AT 120600 UTC.
POSITION GOOD.
REPEAT POSITION 21.7S 174.0W AT 120600 UTC.
CYCLONE MOVING WEST AT 13 KNOTS.
EXPECT SUSTAINED WINDS OF 105 KNOTS CLOSE TO THE CENTRE INCREASING TO 110 KNOTS
BY 121800 UTC.

EXPECT WINDS OVER 63 KNOTS WITHIN 50 NAUTICAL MILES OF CENTRE
EXPECT WINDS OVER 47 KNOTS WITHIN 70 NAUTICAL MILES IN NE QUADRANT
AND WITHIN 90 NAUTICAL MILES IN SE QUADRANT
AND WITHIN 90 NAUTICAL MILES IN SW QUADRANT
AND WITHIN 70 NAUTICAL MILES IN NW QUADRANT
EXPECT WINDS OVER 33 KNOTS WITHIN 120 NAUTICAL MILES IN NE QUADRANT
AND WITHIN 210 NAUTICAL MILES IN SE QUADRANT
AND WITHIN 210 NAUTICAL MILES IN SW QUADRANT
AND WITHIN 120 NAUTICAL MILES IN NW QUADRANT

FORECAST POSITION NEAR 21.4S 176.4W AT 121800 UTC
AND NEAR 21.1S 178.6W AT 130600 UTC.

ALL VESSELS WITHIN 300 NAUTICAL MILES OF CENTRE ARE REQUESTED TO SEND REPORTS
EVERY THREE HOURS TO RSMC NADI. 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 025.

[Cyclone Tracy]

Amercian's ADT now have her 936 hPa , sustained 115 knots and 140 knot gusts, which is another upgrade on last forecast. Pin hole eye is 22.2 km radius

Interesting that the American commentary now having uncertainty on the sharpeness of the poleward left turn in 96 hours. After Hurricane Sandy and Irma, GFS obviously still makes them nervous

[Cyclone Tracy]

Tonga is now in the eye wall. The systems S wobble looks like the pin hole eye will just pass south of Nukulofa based on the last hour's sequence but that could change in the next hour.....

Edit: ADT reading 934 hPa, 117.4 knots sustained winds. Gusting to 145 knots.

[Cyclone Tracy]

ADT = 932 hPa, 119.8 knots sustained. She is now a U.S cat 4 and only 17 knots off U.S cat 5.

[Cyclone Tracy]

GITA is going big. ADT = 125 knots sustained, 150 knots gusts....she will flatten Tonga

[Cyclone Tracy]

Cloud tops in the eye wall on the 10.40pm sat pic now reaching -90c.

edit: Eye now positioned around 35 km south of Nuku'alofa

[Blowy]

Spent a lot of time in Tonga ... it would not take much to flatten 90% of their structures, will be living hell there right now, Has Nukualofa taken a direct hit or not yet? just hope casualties are minimal.

[Cyclone Tracy]

Spent a lot of time in Tonga ... it would not take much to flatten 90% of their structures, will be living hell there right now, Has Nukualofa taken a direct hit or not yet? just hope casualties are minimal.

The inner eye wall is now launching on Nuku'alofa from the south west. They will now be experiencing gusts over 130 knots, maybe more. Even Cat 5 resistant purpose built structures will be in stress. One small positive is that a shallow low tide is around 11.30pm.

[Willoughby]

Powerful winds here:
https://www.facebook.com/fotofilitufui. ... on_generic

[Cyclone Tracy]

Here was the snap shot of the eye south of the Tonga, Nukualofa at 11.10pm last night. Reports that the Met Service lost its roof at the airport with a 275 km/h (148 knots) gust.

[Orion]

Link to ODT article:

https://www.odt.co.nz/news/world/buildi ... shes-tonga

[Cyclone Tracy]

Tonga hard hit.... basically was within the eye wall for several hours in a cat 4 U.S scale cane.

Maintaining around 115 to 125 knots on satellite calculation methods, with 140 to 150 knots gusts. Eye, now closed, uniform CDO. Cat 4 U.S scale. Massive poleward and equatorward outflows allowing her to maintain intensity even in unfavourable wind shear. SST is 29c.

U.S Navy model has continued to have Gita take a sharp left poleward turn and overnight, several models adjusted as well. Plenty of uncertainty on the exact location of poleward turn across 100 models…. Not much point looking beyond 72 hours at the moment IMO.

[Willoughby]

with a 275 km/h (148 knots) gust.

Is there a source for this?

The eye wall and area of maximum winds looked to be too far south from the main island.

"Estimated radius of max. wind based on IR :<10 km"

The capital might have got 70 or 80 knots but they definitely missed the nasty stuff.

[jamie]

From memory the airport is on the SE side and the capital is on the northern side.

I would think the air port would have recorded higher winds than the capital.

[Cyclone Tracy]

with a 275 km/h (148 knots) gust.

Is there a source for this?

The eye wall and area of maximum winds looked to be too far south from the main island.

"Estimated radius of max. wind based on IR :<10 km"

The capital might have got 70 or 80 knots but they definitely missed the nasty stuff.

NZ Herald this morning. Airport is on the exposed far SE corner but I haven't seen an official reading for 275 km/h.

[Willoughby]

Yeah I can assure you there'd be more missing than the roof if it was a 275 km/h gust!

Seems like a classic regurgitation of hypothetical wind strengths based on the warning.

[jamie]

Yea the damage to me doesn’t look like eye wall cat 4/5. I would expect to see all vegetation stripped like we have seen with recent cat 5 storms. This makes me think they dodged a bullet by the narrowest of margins. Not to take away from the horror these people have already been through tho.

[Cyclone Tracy]

Couple of interesting informational tweets

https://twitter.com/StuOstro/status/963100252059422720

https://twitter.com/iCyclone/status/963008263510925312

[Cyclone Tracy]

Just having a quick check of ADT, she has taken her foot off the gas for the moment.

- Last night she dropped 36 hPa in 17 hours
- Currently around the low 940’s
- Currently sustained winds have dropped to 107 knots
- Currently centre cloud tops now near -70c
- Currently no eye

[Cyclone Tracy]

GITA is now an annular tropical cyclone. Transitioned from asymmetric to symmetric ‘annular’ during the last 12 hours and has maintained intensity ranging from 107 to 117 knots based on ADT method. Wind shear unfavourable but offset by strong outflows. Cat 4, cruising west at 9 knots, has slowed slightly.

- Core has warmed to 12c
- Central pressure 934 hPa
- Sustained winds 117.4 knots
- Clear eye

Interesting that in 72 hours, GFS 1302 12Z is taking her slightly more north towards New Caledonia which if correct, will mean more land interaction with the outer bands, which has potential to slow her slightly.