Tropical Cyclone Sarai - Fiji

[Cyclone Tracy]

South Pacific convergence zone will become quite lively just after Christmas. Most models are showing a tropical depression developing around Boxing day north of Vanuatu. The main EC control run today (20/12 12Z) producing a RI severe tropical cyclone riding the subtropical ridge towards Fiji on the 29th.

TC EC 2012 12Z.jpg

[Cyclone Tracy]

Invest 99P now up and running

Invest 99P.jpg

[Cyclone Tracy]

Looking at the main models this evening EC and GFS take a cat 2 to 3 direct hit on Fiji this weekend. Interestingly, the UK for the last 2 runs continues to strengthen the subtropical ridge and positions the mid latitude trough more west. This steers the cyclone 700 to 800km further west than EC & GFS. Locals and holiday makers in Fiji this weekend will be barracking for the UK scenario to stick.

99P 3 models.jpg

[Chris W]

Metservice increasing the potential for development from low through high in the next couple of days.

[Cyclone Tracy]

Invest 99P / TD03F is now producing hot towers on either side of the depression's low level circulation centre, cloud tops near -100c at midday NZT. The likelihood of the TD now becoming a tropical cyclone is high, with environmental conditions to the south favourable in the next 72 hours. The tropical cyclone will be named TC Sarai by Fiji Met once the 34 knot, 10 min sustained wind level threshold is reached.

99P 2412.jpg

[Cyclone Tracy]

Soon to be TC Sarai is becoming organised. A hot tower exploding into the stratosphere at 6.30am NZT Christmas day.

99P 2512.jpg

[GraemeWi]

Will be watching this develop - quite a good webcam on Malolo Lailai at the southern end of the Mamanuka Island group looking to the North West http://www.plantationisland.com/webcam/

[Cyclone Tracy]

JTWC have now pulled the trigger and given the depression cyclone status. 35 knots sustained 1 min winds, Fiji met won't be too far away now from the official naming.

[Nev]

Thought TC Sarai, named by Fiji Met early this morning, could do with its own thread.

TC Sarai - Nadi Track-map - Dec 26, 1433z.png

TC Sarai - JTWC Track-map - Dec 26, 1500z.gif

TC Sarai - Hima rb - Dec 26, 1700z.jpg

[Cyclone Tracy]

Sarai starting to deepen just NW of the Nadi. Outflow is improving. EC has produced a north east track 48 hours from now with the exit door to the mid latitudes blocked by the subtropical ridge. This could be a prolonged wet and windy time for Fiji if EC verifies.

9.50am 271219.jpg

[GraemeWi]

PWS not too far from the webcam I linked earlier - https://www.wunderground.com/dashboard/pws/IWESTERN880

Gusting to 80 kph with steadily building wind

[Cyclone Tracy]

Nadi radar showing a ragged eye around 200 km WNW of Nadi at 3:40pm. Dvorak satellite estimating method showing the central pressure 983 hPa and around 50 knot winds.

Nadi radar 3.40pm local.jpg

[Cyclone Tracy]

Will be watching this develop - quite a good webcam on Malolo Lailai at the southern end of the Mamanuka Island group looking to the North West http://www.plantationisland.com/webcam/

Good cam to watch. Storm surge starting to appear after 7pm tonight.

[Nev]

TC Sarai has been upgraded to Cat 2 this evening…

TC Sarai - Nadi Track-map - Dec 27, 0819z.png

[Cyclone Tracy]

Overlaying IR / water vapour with the favourable wind shear environment, Sarai has a good chance to intensify more overnight with the sea surface between 28 to 29c beneath. Radar will need to be watched closely by locals tonight.

IR WV2712.jpg

[Cyclone Tracy]

Sarai has slowed in the last few hours with some outer ingestion of dry air as seen on the latest water vapour image. Currently a strong cat 2, 65 knots and 980 hPa. Plenty of uncertainty in the next 48 hours across the main models. EC's latest 18Z run continues to stall the system and send it north towards Suva as a cat 1 tomorrow night.

Sarai 2812 WV.jpg

[Cyclone Tracy]

Sarai has moved NE overnight, closer and SSE of Suva. 70 knot winds , around 970 hPa and very near Cat 3 status. An eye has appeared a few times overnight.

From this point, is where models differ due to the projected strength of the short wave trough..... UK and GFS are heading east, EC is heading north east. Tonga would be quite interested in the UK scenario which shows a near direct hit at cat 2 level around New Years eve.

[Cyclone Tracy]

well well, this is interesting..... lightning is now appearing around Sarai's ragged inner eyewall. A sign the system is trying to intensify. Normally only Cat 3 to 5 display this behaviour.

Sarai 2912 Sat lightning.jpg

[Awhituobs]

Slow moving hurricanes / TC,s seem to be a norm now around the globe ... lighter upper level steering or more blocking??

[TonyT]

Slow moving hurricanes / TC,s seem to be a norm now around the globe ... lighter upper level steering or more blocking??

Weaker zonal airflow and more meridional flow around solar minimum. Zonal flow will pick up again in the next few years as solar cycle 25 ramps up (looks like we have hit minimum late this year as new SC25 configuration sunspots are now starting to appear). Interesting that Accumulated Cyclone Energy in the Southern Hemisphere appears to be on a long term downward trend (not that ACE is the same thing as cyclones being slower moving as you noted, but still).

global_annual_ace.png

[Cyclone Tracy]

Increased wind shear starting to take a toll on Sarai this morning. An asymmetrical weakening cat 2. 60 Knots, around 982 hPa. Currently around 390km WNW of Tonga.

[Nev]

Increased wind shear starting to take a toll on Sarai this morning. An asymmetrical weakening cat 2. 60 Knots, around 982 hPa. Currently around 90km ENE of Tonga.

Hmm... JTWC currently put Sarai about 350km west of the Tonga group and due to impact the archipelago later tomorrow. But yes, looking a bit shabby this morning with a partially exposed LLCC and convection sheared to the east. Fiji Met has dropped mean-winds down to 50 knots, so on the low end of a Cat 2.

TC Sarai - Nadi Track-map - Dec 29, 1949z.png

TC Sarai - JTWC Track-map - Dec 29, 2100z.gif

TC Sarai - Hima rgtp - Dec 29, 2030z.gif

[Cyclone Tracy]

Hmm... JTWC currently put Sarai about 350km west of the Tonga group

I missed the 3 and got the direction the opposite. Not my best post now corrected.

[Nev]

TC Sarai was downgraded to Cat 1 around 2am this morning. Sarai has also tracked further south than previous forecasts and is now expected to cross Tonga's main island of Tongatapu tonight this afternoon (assuming she's still intact by then).

TC Sarai - JTWC Track-map - Dec 30, 1315z.png

TC Sarai - JTWC Track-map - Dec 30, 1500z.gif

TC Sarai - Hima rbtp - Dec 30, 1600z.gif

[Nev]

TC Sarai still just barely a Cat 1 as she passsed Tonga's main island of Tongatapu at around 1pm today, although JTWC had her about 50 km north of the capital, Nuku'alofa, while Fiji Met had her about 30 km to the south.

TC Sarai - JTWC Track-map - Dec 31, 0059z.png

TC Sarai - Hima rgb - Dec 31, 0000z.gif