APCEDI Alert SP/SI Cyclone Yani (02P/04F)#2-2007: Cyclone Yani forms South of Makira in Solomon Islands

The RSMC-Nadi Tropical Cyclone Centre and the Joint Typhoon Warning Centre continue to issue guidance on Cyclone Yani that formed today from Tropical Depression 02P (04F), which has been slowly strengthening and meandering south of Makira.

Cyclone Yani is currently centred 150 km southeast of Makira or 200 km east of Bellona. It is at Tropical Storm strength on the Saffir Simpson Scale. It is moving very slowly southeast at 2-4 kts with a forecast shift in direction to the south and southwest, but continued slow meandering is likely in the next 12-24 hours along with slow strengthening.

On its current slow southeasterly track, no land areas are immediately threatened, and the storm is still small. However, all interests in Makira, Guadalcanal, Rennell and Bellona should pay close attention to this storm and be ready to make any preparations should conditions warrant and authorities advise. Seas in the area are becoming rough and local boating interests should stay advised. All interests in Northern Vanuatu should also monitor this storm.

Early season storms are notoriously unpredictable, and current model guidance for Yani has been all over the place, providing little useful forward prognosis.

From the RSMC-Nadi Tropical Cyclone Centre

Tropical Disturbance Advisory Number A2 issued from RSMC NADI
Nov 22/0214 UTC 2006 UTC.

Tropical Cyclone YANI 04F [995hPa] centre was located near 12.3S 162.5E at 220000 UTC moving southeast about 04 knots. Position fair based on HRES MTSAT VIS and EIR imageries with animation. Maximum 10-minute average winds estimated at 35 knots within 120 miles of centre in the southern semicircle and within 60 miles of centre in the northern semicircle increasing to 45 knots in the next 12 to 24 hours.

Organisation steadily increasing with primary band wrapping tightly around llcc. Convection increased spatially and tops have begun cooling again after a brief warming. Outflow good to south but restricted elsewhere. Dvorak based on curved band wrap of 0.6 on log10 spiral thus T3.0/3.0/D2.0/24hrs. Cyclone is located just south of a 250-hPa rige axis in a region of 5-10kt shear. SST around 28-29C. Global models struggling with Yani. Obtaining a sensible consensus impossible. System expected to move southeast further before turning southwest under a north to northeast steering regime in the next 24 hours.

FORECAST:
12hrs valid 221200UTC near 13.2S 162.8E mov SSE at 04kt with 40kt close to centre.
24hrs valid 230000UTC near 14.5S 162.5E mov SSW at 04kt with 45kt close to centre.

OUTLOOK:
36hrs valid 231200UTC near 14.3S 161.8E mov SW at 05kt with 50kt close to centre.
48hrs valid 240000UTC near 14.8S 161.0E mov SW at 05kt with 55kt close to centre.

The next Tropical Disturbance Advisory on TC YANI will be issued around 220800 UTC.
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APCEDI will continue to issue further bulletins on Cyclone Yani as the need arises.

Kevin Vang
APCEDI Coordinator

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