Somerset Squall

A new tropical cyclone has formed just south-southwest of Diego Garcia. Deep convection is persisting over the core of the 35kt system, and convective banding is becoming better defined. Shearis low and waters warm, however, the air is a little dry, and this could begin to interfere with development in the next few days. Still, 05S should strengthen modestly over the next few days, before the southerly track takes 05S over colder waters and much higher shear. 05S should remain east of La Reunion.

Cloudy and windy with showers. Temperature: 12.5°C Humidity: 77% Pressure: 1013mb Wind: 20mph, gusting 35mph, from the west-southwest

Tuni has not strengthened beyond 40kts. Shear has continued to plague the cyclone, shearing convection away from the LLCC. Extratropical transition will begin very soon as the system continues to slip southeast.

It's certainly been a truly amazing year in the Pacific. The most remarkable thing to me has been the record breaking Central Pacific activity.

A tropical cyclone named Tuni has formed in the South Pacific, a couple hundred miles west of Pago Pago, American Samoa. JTWC estimate winds to be at 40kts. Tuni has good banding features and slightly displaced central convection due to moderate northwesterly shear. This shear should prevent Tuni from becoming too intense as it tracks towards the southeast, but will not be enough to stop some strengthening. JTWC indicate a peak of 55kts, likely to occur within the next 24-36hrs, because after, shear will rise to destructive levels, and sea temperatures will decline along track, initiating extratropical transition.

Sandra is being destroyed by shear. Winds are down to 55kts, and are falling rapidly. Sandra's convection resides well northeast of the exposed LLCC. Sandra is likely to weaken to a tropical depression soon, and will likely degenerate into a remnant low before hitting the coast.

Sandra has become a category 4 hurricane with winds of 125kts, unprecedented for so late in the season. The hurricane has probably done strengthening as shear values are much higher along Sandra's northward track.

Sandra has become the 9th major hurricane of the Eastern Pacific season. This is another record for the basin. Winds are at 100kts. Further intensification is likely over the next 12 hours, followed by weakening as shear rises on the northeasterly track.

Increasingly well defined eye:

Sandra has become a category 2 hurricane, with winds of 85kts. Sandra is now the strongest hurricane on record for so late in the season. And it's strengthening isn't done yet. Further rapid intensification is likely.

Latest NHC advisory ups the winds to 75kts. Sandra is quite a small hurricane, meaning rapid intensification is more likely.

Sandra has become a hurricane overnight, with winds now at 65kts. The central dense overcast has become solid and there have been glimpses of an eye overnight. Conditions favour potentially rapid intensification, and NHC now forecast Sandra to peak at 100kts, a cat 3 major hurricane. They even say this estimate could be conservative.

22E has become Tropical Storm Sandra, with winds of 40kts. Sandra's inner core has tightened, and a small central dense overcast has formed, along with a well defined primary banding feature to the north. Model intensity forecasts have backed off the kind of strengthening they were forecasting earlier. This is surprising, given that shear is low, waters anomalously warm, and humidity high. NHC are forecasting a peak of 80kts due to the model intensity guidance, but the environmental factors seem to suggest that Sandra could become stronger than this.

In-fa peaked at 115kts. The typhoon is now recurving and weakening under increased shear. As In-fa continues northeast southeast of Japan, it should begin to lose tropical characteristics as it moves over decreasing sea temperatures.

A very late season tropical depression has formed to the south of the Gulf Of Tehuantepec. Winds are at 30kts. 22E has a small, well defined LLC, tucked beneath a cluster of deep convection. Shear is low and waters are anomalously warm, near 30°C. These factors suggest strengthening will occur. Just how much is open to question, but models are quite keen on making 22E a hurricane, with some models forecasting 22E to be near major hurricane strength at peak. A westward track is expected over the day or so, followed by a recurve northeastwards towards Baja California. The recurve will be induced by an approaching trough, which should serve to weaken the system in the longer range, before any landfall.

Rick has degenerated into a convectionless remnant low. Regeneration is not expected.

Temperature got down to -2.9°C overnight. Remaining cold and misty at the moment. Current Obvs: Temp: -2.0°C Humidity: 95% Pressure: 1026mb Wind: 2mph, variable

Annabelle has had an intermittent eye feature overnight, which has recently become cloud filled again. Winds are up to 60kts according to JTWC. Time is running out for Annabelle to strengthen, as shear is beginning to increase and the southward track begins to take Annabelle over cooler water.

03S has slowly strengthened, and now has winds of 50kts according to JTWC. The storm has been named Annabelle by MeteoFrance. The storm is crawling towards the south currently, but should accelerate to the southeast soon as ridging to the northeaat begins to dominate. JTWC expect a peak of 60kts before Annabelle becomes overwhelmed by shear and moves over cooler waters.

In-fa has continued to strengthen, with winds now at 115kts, a category 4 on the SS scale. Some further intensification is expected, and a peak of 125kts is forecast. Quite lucky that this typhoon didn't take the more northern route through Guam as originally expected.

Rick has not strengthened, and has instead been attacked by shear again. The LLCC is partially exposed from the declining deep convection. Little change in strength is forecast over the next day or so as Rick moves northwest. Thereafter, even stronger shear awaits, bringing about this weak storm's demise in a few days time.

The first tropcial cyclone of the South Indian Ocean cyclone season 2015-16 has formed about 175 miles south-southwest of Diego Garcia. The system has winds of 35kts according to JTWC, and is characterised by a well defined circulation and good convective banding. Strengthening is expected over the next few days, as outflow remains very good and waters warm in this time. Thereafter, as 03S slips southeast, it'll move over cooler waters and increased shear, inducing weakening.

After a day of arrested development, In-fa is now intensifying quicker as it gets ready to pass to the south of Guam. Winds are up to 90kts, a cat 2 on the SS scale. The typhoon has developed a small, well defined eye. Further intensification appears likely.

21E has gradually strengthened and is now Tropical Storm Rick, with winds of 35kts. Convection has become deeper over the LLCC, an indication that shear is relaxing. Some further intensification is expected over the next day or so, before shear rises dramatically. According to NHC, only 3 storms have formed later than Rick in reliable recorded history.

A late season tropical depression has formed, well south-southeast of the southern tip of Baja California. 21E has winds of 30kts, and consists of a partially exposed LLCC to the southeast of a mass of convection. Moderate shear is currently affecting 21E, resulting in this structure. Shear is expected to lessen over the next few days, and as 21E moves over warm water, it should strengthen. The only limiting factor in the 24-72hr time period is low humidity in the region. With the low shear and warm water, NHC are forecasting a 60kt peak for 21E, so it has a good shot at potentially becoming a hurricane. In 72hrs time, shear will rise dramatically, killing the system.