Somerset Squall

Another tropical depression has formed, in the east of the basin, north-northeast of Pohnpei. 25W has winds of 25kts. Strengthening is forecast as the system heads west-northwestwards along the south side of a ridge to the north. In a few days time, as 25W passes north of Guam, sea surface temperatures will be lower and shear is expected to rise, which will likely stop or slow any further intensification.

A new tropical storm has formed a few hundred miles west-northwest of Guam. Named Koppu, the storm has winds of 35kts. Moderate shear is plaguing Koppu, which should make intensification over the next couple of days quite slow. Beyond, shear will drop off, and on approach to the Philippines, Koppu will traverse waters of 30°C. Rapid intensification is expected in this time frame, with a peak of 125kts forecast by JTWC before Koppu slams into Luzon. There is some model disagreement, with some models favouring a northward turn before reaching Luzon. So a landfall is not set in stone by any stretch. Luzon need to be prepared for a potential landfall however.

Nora has moved into the Central Pacific overnight. The storm has slowly strengthened and now has winds of 50kts. Nora is a small tropical storm and moderate shear has prevented quick intensification. Nora is forecast to strengthen a little more, and is now expected to peak at 60kts, just below hurricane intensity. After the peak, shear will rise causing weakening to begin.

The eighteenth tropcial depression of the Eastern Pacific season formed yesterday and has now strengthened to Tropical Storm Nora in the far west of the basin, not far east of the eastern boundary of the Central Pacific. Indeed, it appears Nora will be another system to cross into the Central Pacific over the coming days. Nora is moving slowly westwards, but should soon turn west-northwest, then north then northeast over the next 5 days. The reason for this is a breakdown of the ridging to the north currently in control of Nora due to a trough moving eastwards north of Hawaii. This should induce a recurve well southeast of Hawaii. Nora is forecast to strengthen over the next few days as shear is low to moderate, and sea temperatures are warm. By day 4 and 5, shear will be increasing as the trough picks up Nora, and waters will cool along track, beginning a weakening trend. Before that, NHC expect a peak of 80kts (cat 1 hurricane).

Oho didn't make it into the Central Pacific and became extratropical before making the cross.

Choi-Wan peaked at 70kts and has now become extratropical whilst racing northward east of Japan.

Oho peaked at 95kts, just shy of Major Hurricane status. The hurricane is now rapidly losing organisation due to very high shear and passage over much colder waters. Oho should continue to gain lattitude very quickly and will likely soon become extratropical whilst moving into the waters west of Canada. A bizarre track for a Central Pacific storm. There is a chance that Oho will remain tropical long enough to cross 140°, moving into the Eastern Pacific basin. IF it does, then Oho may well be the first Central Pacific named system to cross into the Eastern Pacific.

Indeed Vorticity, winds are now at 90kts, which is cat 2 on the SS scale. Interesting how quiet the Eastern Pacific has been recently, with all the activity focussed on the Central Pacific. Oho has certainly been impressive, could it get even stronger I wonder? Time is running out.

Choi-wan became a typhoon late yesterday and has since strengthened to 70kts. The typhoon could strengthen a little more over the next 12hrs before shear increases and waters cool along track, initiating extratropical transition. Chan-hom is likely to become quite an intense extratropical cyclone over the North Pacific.

Oho is moving northeastwards at a faster pace. Shear has reduced over the system, which has allowed a central dense overcast and the beginnings of an eye to take shape. Oho has therefore been upgraded to a hurricane with winds of 65kts. A little further intensification is expected in the next 24hrs, before shear rises and waters cool along track.

Choi-wan's structure has vastly improved this morning with convection now persisting over the LLCC, with the circulation of Choi-wan also having become much better defined aswell (ie much less broad). Winds are up to 60kts. Choi-wan is heading generally westwards but should soon turn to the north as it reaches the western extent of the steering ridge to the north. Further intensification is likely, with JTWC forecasting a cat 2 peak with 85kt winds before weakening over cooler water and higher shear.

Oho has moved very little in the last 36hrs, and has been meandering on the spot pretty much. An acceleration to the northeast is expected soon as a digging trough to the northwest eventually gets close enough to Oho to increase the steering currents. The track still takes Oho well to the southeast of Hawaii, so impact shouldn't be severe unless there are changes. Moderate shear has plagued Oho over the last couple days, which was unforseen. Therefore, only slight intensification has occured, with winds of 45kts. Shear is expected to temporarily ease later roday and through the first half of tomorrow, allowing some further intensification. Oho however, is no longer forecast to become a hurricane, and instead is forecast to peak at 55kts. Thereafter, in about 36hrs time, the trough responsible for taking Oho northeastwards will become close enough to not only do that, but to increase she shear over Oho again, causing weakening.

08C degenerated into a remnant low yesterday afternoon as strong shear prevented convection from persisting over the LLCC. Since degeneration, some convection has fired to the north of the LLCC, but centre itself has remained completely exposed. Strong shear is expected to continue over the next day or two, but could ease after that time. So there is a small chance of regeneration if there is anything left of the low at this point.

Choi-wan is very slowly intensifying, with winds now at 50kts according to JTWC. The storm remains very broad, with the majority of the convection to the southwest and northeast of the LLCC, and not over the LLCC itself. Whilst Choi-wan has this structure, it will find it difficult to strengthen. JTWC still expect Choi-wan to become a typhoon in about 24hrs before it recurves northeast into stronger shear and cooler waters.

It would feel pretty pleasant and, dare I say it, warm if that came off

"Reports have come out about multiple fatalities (albeit unconfirmed) taking place in the Bahamas, with Long Island being particularly devastated. Fatalities from hurricanes in the Bahamas are very uncommon, a testament to the level of devastation from Joaquin. Long Island remains flooded with reports of animal bodies floating in the stagnant water. It's not a pretty picture at all, to say the least. Communities remain isolated and in desperate need of assistance. Goes without saying that Joaquin could be one of the Bahamas' worst natural disasters in quite some time." Quote from the Atlantic hurricane Facebook group.

And indeed Mujigae did get stronger, a lot stronger!!! Winds are up to 115kts, which is a category 4 on the SS scale. Mujigae has just made landfall near Zhanjiang, China. Now Mujigae is inland, it should weaken nearly as rapidly as it strengthened. This is a slightly old image which shows Mujigae's eye nicely, along with the circular central dense overcast. This typhoon rapidly became a monster, I do hope the people it is affecting were not caught too offguard just expecting a minimal typhoon to make landfall. Mujigae definitely isn't that. This rapid intensification just prior to landfall in southern China reminds me of Typhoon Vicente in 2012, which similarly caught forecasters off guard by becoming a cat 4 just before landfall when it was only forecast to be a cat 1.

Wow, I am impressed! I did not expect Joaquin to be a 135kt cat 4 this afternoon. That was an impressive burst of intensification as it moves to the northeast away from the Bahamas. A bizarre track, and a very interesting hurricane to follow.

Mujigae has continued to strengthen, and is now a typhoon with winds of 65kts. The storm has a circular central dense overcast, and a small eye is becoming apparent. Some further intensification is possible before landfall in the next 12hrs. JTWC are forecasting a peak of 70kts, but I think Mujigae could get a little stronger than that based on the fact the typhoon is already developing a well defined eye.

Yet another tropical depression in this crazy Central Pacific season has formed well to the west-southwest of Hawaii. 08C has winds of 30kts. The depression consists of a closed low level circulation just about tucked in on the south side of a large mass of convection. Moderate southerly shear is displacing most of the convection to the north. Shear is not expected to significantly ease over the next few days, and models are not keen on strengthening 08C, or dissipating it either. Therefore, the CPHC forecast keeps 08C a tropical depression for the next 5 days as it moves westwards and eventually into the Western Pacific (yes, another basin crosser if 08C survives long enough!).

07C has become Tropical Storm Oho, with winds of 35kts. Quite often, we will only use 1 name in a year, sometimes we will go a couple years without a named storm in the Central Pacific. Oho is the 8th named storm of the Central Pacific 2015 season. Amazing!

The record breakingly active Central Pacific season continues with the formation of Tropical Depression 07C, 400 miles south of the Big Island of Hawaii. Convection is persistant over the LLCC, with banding features becoming more prominent. If this organisational trend continues, 07C will soon be a tropical storm. Strengthening is forecast as shear is low and waters very warm along track. 07C is expected to become a hurricane in 2-3 days time. 07C is currently heading northeastwards slowly as a trough to the north has a weak steering influence on 07C. This trough will be replaced by a ridge in a couple days time, allowing 07C to turn northwestwards. This ridge is only expected to temporarily influence 07C, and a turn back to the northeast is then expected on 4-5 days time, to the southeast of Hawaii. This is a fairly unusual track, and changes will more than likely occur as the steering environment is complex.

The 23rd tropical cyclone of the Western Pacific season has formed in the far east of the basin, just south of Wake Island. Choi-wan has winds of 35kts. Choi-wan is a large, sprawling storm with a large expanse of storm force winds. The storm is currently heading westwards along the south side of a ridge to the north. Choi-wan will continue westwards then turn to the northwest then north as it reaches the western extent of the ridge. Shear is low, and waters warm, which suggests Choi-wan will continue to intensify at at least a steady pace over the next few days. JTWC expect a peak of 85kts before weakening eventually begins on day 5 due to increasing shear and cooler waters in the higher latitudes.

22W became a 35kt tropical storm named Mujigae before landfalling on the east coast of Luzon. The storm then weakened to a tropical depression over land before emerging over water in the South China Sea. Mujigae has since strengthened quickly, and now has winds of 55kts. The storm has a well established central dense overcast, good banding, and the beginnings of an eye. Mujigae will soon become a typhoon before making a second landfall, this time in southern China, north of Hainan Island.

Dujuan has moved inland over China and dissipated. 3 deaths have been reported but damage to Taiwan was extensive.